BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a reverse osmosis membrane element replacing device and a reverse osmosis membrane filtration apparatus including the reverse osmosis membrane element replacing device. The present invention particularly relates to a reverse osmosis membrane element replacing device and a reverse osmosis membrane filtration apparatus that can efficiently replace reverse osmosis membrane elements even if multiple pressure vessels housed in a pressure vessel.

2. Description of the Related Art

Japanese Patent Application Laid-open No. H6-114239 discloses a method of replacing a reverse osmosis membrane element in a seawater desalination system. In this method, among reverse osmosis membrane elements arranged in a pressure vessel (vessel), a used reverse osmosis membrane element is removed from an opening on one side (a supply water side or a permeated water side) of the vessel, and a new reverse osmosis membrane element is inserted and housed into the vessel from an opening on the other side.

However, the reverse osmosis membrane element replacing method disclosed in Japanese Patent Application Laid-open No. H6-114239 is to set the maintenance period short (yearly, in the embodiment) and to replace only the reverse osmosis membrane elements located at extreme side. This method requires maintenance to be performed frequently, and therefore, has poor operation efficiency. Another problem is that workers are simultaneously required to work at the two openings of the vessel, i.e., on the supply water side and a filtered water side. This leads to poor operation efficiency.

If all the reverse osmosis membrane elements housed inside the vessels are to be replaced to improve the operation efficiency of the seawater desalination system, the following problems are encountered. In recent years, in the seawater desalination systems, with an object of producing large quantities of treated water, larger diameter reverse osmosis membrane elements are used, and, in addition, longer vessels are used to accommodate more reverse osmosis membrane elements in the vessel. However, in this structure, a sliding resistance (frictional resistance) generated when inserting a reverse osmosis membrane element into the vessel increases, making manual insertion and removal operations of the reverse osmosis membrane element difficult.

With a view to lessening the workload of the workers, a technique for realizing automation of reverse osmosis membrane element replacement operation is disclosed in International Publication No. 2011/007326. In this technique, vessels are arranged vertically in a seawater desalination system, and reverse osmosis membrane elements are inserted into the vessels by a hoisting method or a pushing method. As a result, the operations of hoisting, turning, and pushing the reverse osmosis membrane elements do not need to be performed manually, and hence the workload of the workers is reduced.

However, because the vessels are vertically arranged in the technique disclosed in International Publication No. 2011/007326, a load for hoisting or pushing the reverse osmosis elements increases as the number of reverse osmosis elements to be housed inside a vessel increases. Because this load is equal to gravitational acceleration added to the weight of a reverse osmosis membrane element, the load is evidently larger than the sliding resistance (frictional resistance) generated when pushing a horizontally arranged reverse osmosis membrane element into the vessel.

Moreover, there are concerns regarding the safety during the job of inserting reverse osmosis membrane elements, which are heavy bodies, into the vertically arranged vessels; because, the reverse osmosis membrane element may fall when it is being inserted in the vessel.

In this regard, a technique aimed to reduce the sliding resistance generated when inserting a reverse osmosis membrane element has been disclosed in International Publication No. 2009/104750. Specifically, an inner peripheral surface of the vessel is subjected to a frictional resistance reduction process to reduce the frictional resistance generated between the reverse osmosis membrane element and the inner peripheral surface of the vessel. Although the concrete means to impart the frictional resistance reduction process is not particularly limited, ridges and grooves, a material or members having highly slippery surface or quality, or a rotary body arranged on the inner peripheral surface of the vessel can serve as the means. By reducing the sliding resistance of the reverse osmosis membrane element by using such means, the replacement operation of the reverse osmosis membrane element can be performed easily, and the operability can be improved.

However, in the seawater desalination system that includes the reverse osmosis membrane element, the pressure vessels into which reverse osmosis membrane elements are housed are arranged horizontally in the form of a module such that the openings of the vessels through which the reverse osmosis membrane elements are inserted fall in one plane. However, because the openings are arranged in an array in both horizontal and vertical directions of the plane, the replacement operation requires an operation to be performed at elevated places. Conventionally in this case, an armlift that holds the reverse osmosis membrane element to be replaced is placed on a forklift, etc., and the reverse osmosis membrane element is hoisted up to the height of the opening, where the worker guides the reverse osmosis membrane element into the opening. Thus, the operation efficiency can be improved only up to a limited level and there are safety issues in the operation because of the workers having to work at elevated places.

SUMMARY OF THE INVENTION

In view of the above discussion, it is an object of the present invention to provide a reverse osmosis membrane element replacing device and a reverse osmosis membrane filtration apparatus including the reverse osmosis membrane element replacing device that can efficiently replace reverse osmosis membrane elements even if multiple pressure vessels are housed in the pressure vessel while upholding safety during the operation.

To achieve the above object, according to an aspect of the present invention, a reverse osmosis membrane element replacing device that replaces a reverse osmosis membrane element from a reverse osmosis membrane module that includes a plurality of pressure vessels arranged in a stack, and into which the reverse osmosis membrane element, which is formed by a rolled up reverse osmosis membrane, is fitted, with openings of the pressure vessels, through which the reverse osmosis membrane element is inserted, facing in the same direction and arranged in the same plane, includes a placement base that can be positioned facing any one of the opening and carries the reverse osmosis membrane element with an end thereof oriented in a pushing direction of the reverse osmosis membrane element from the opening toward the pressure vessel; a first moving unit that moves the placement base in a first direction that is perpendicular to the pushing direction; a second moving unit that moves the placement base in the pushing direction and a second direction that is perpendicular to the first direction; a driving unit that pushes the reverse osmosis membrane element riding on the placement base into the pressure vessel by moving a rod facing the opening to the pressure vessel side and removes the reverse osmosis membrane element accommodated inside the pressure vessel by moving the rod that is abutting the reverse osmosis membrane element inside the pressure vessel via a coupling unit in a direction away from the pressure vessel; and a control unit that controls movement amounts of the first moving unit and the second moving unit so as to cause the reverse osmosis membrane element riding on the placement base to face any of the openings and drives the driving unit.

According to another aspect of the present invention, in a reverse osmosis membrane filtration apparatus, the above reverse osmosis membrane element replacing device is arranged at a position facing the openings of the reverse osmosis membrane module.

The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a set of drawings showing a front view of a reverse osmosis membrane element replacing device according to an embodiment of the present invention and a front view of a reverse osmosis membrane module that is to be applied to the reverse osmosis membrane element replacing device;

FIG. 2 is a perspective view of FIG. 1 (with a placement base omitted);

FIG. 3 is a perspective view of the reverse osmosis membrane element according to the present embodiment;

FIG. 4 is a side view of the placement base according to the present embodiment;

FIG. 5 is a plan view of the placement base according to the present embodiment;

FIG. 6 is a schematic diagram of a driving unit according to a first concrete example of the present invention;

FIG. 7 is a schematic diagram of a driving unit according to a second concrete example of the present invention;

FIG. 8 is a perspective view for explaining an operation (before pushing in) of the reverse osmosis membrane element replacing device according to the present embodiment;

FIG. 9 is a perspective view for explaining an operation (after pushing in) of the reverse osmosis membrane element replacing device according to the present embodiment;

FIGS. 10A and 10B are a set of schematic diagrams of a driving unit according to a third concrete example of the present invention where FIG 10A is a schematic diagram of the driving unit in a retracted state and FIG 10B is a schematic diagram of the driving unit in an extended state;

FIG. 11 is a perspective view for explaining an operation (during retraction) of the driving unit according to the third concrete example;

FIG. 12 is a perspective view for explaining an operation (during a first step of extension) of the driving unit according to the third concrete example;

FIG. 13 is a perspective view for explaining an operation (during a second step of extension) of the driving unit according to the third concrete example;

FIG. 14 is a set of drawings for explaining a removal process of the RO membrane element using a coupling unit according to the first concrete example;

FIG. 15 a drawing showing a case in which the RO membrane element is removed using a coupling unit according to the second concrete example;

FIG. 16 is a cross-sectional view taken along a line A-A of FIG. 15;

FIG. 17 is a cross-sectional view taken along a line B-B of FIG. 15;

FIG. 18 is a view along an arrow C of FIG. 15, and shows a state when the coupling unit has gone past projecting members;

FIG. 19 is a view along the arrow C of FIG. 15, and shows an arrangement during removal of the RO membrane element by turning the coupling unit after the coupling unit has gone past the projecting members;

FIG. 20 is a schematic diagram of a loading unit according to the first concrete example;

FIG. 21 is a schematic diagram of a loading unit according to the second concrete example; and

FIG. 22 is a schematic diagram of a loading unit according to the third concrete example.

DETAILED DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of the present invention are explained in detail below with reference to the
accompanying drawings. However, constituent elements, categories, combinations, shapes, and their relative positions, etc., mentioned in these embodiments are merely simple explanatory examples, and the scope of the present invention is not limited to these, unless specifically stated otherwise. Furthermore, an X-axis (horizontal direction), a Y-axis (horizontal direction), and a Z-axis (up-and-down direction) shown in the drawings are orthogonal to each other.

FIG. 1 is a set of drawings showing a front view of a reverse osmosis membrane element replacing device according to an embodiment of the present invention and a front view of a reverse osmosis membrane module 100 that is to be applied to the reverse osmosis membrane element replacing device.

FIG. 2 is a perspective view of the structure shown in FIG. 1 (with a placement base omitted). The reverse osmosis membrane module 100 according to this embodiment is, for example, a module for extracting fresh water from seawater. A reverse osmosis membrane filtration apparatus includes the reverse osmosis membrane module 100 and a reverse osmosis membrane element replacing device 10 according to this embodiment.

The reverse osmosis membrane module 100 includes a plurality of cylindrical pressure vessels 102 arranged in a stack and bound together. The longitudinal directions of the pressure vessels 102 (vessels) are aligned in the horizontal direction (in the Y-axis direction). Multiple reverse osmosis membrane elements (hereinafter, "RO (Reverse Osmosis) membrane element") are housed in each of the pressure vessels 102.

Furthermore, in the reverse osmosis membrane module 100, openings 104 of the pressure vessels 102 from where the RO membrane elements 108 are inserted and/or removed (FIG. 3) are located in one plane (a plane on -Y-axis side of the reverse osmosis membrane module 100). That is, as shown in FIGS. 1 and 2, the pressure vessels 102 are supported by a frame 106 and are arranged in an array in the horizontal direction (X-axis direction) and the up-and-down direction (Z-axis direction), with the openings 104 forming an array surface (XZ plane).

FIG. 3 is a perspective view of the reverse osmosis .membrane element. As shown in FIG. 3, the RO membrane element 108 used in the present embodiment includes a central pipe 110, bag-shaped reverse osmosis membranes 112, and mesh spacers 114 that enable raw water (salty water) to pass through. The reverse osmosis membranes 112 and the mesh spacers 114 are rolled around an outer periphery of the central pipe 110 to form a multilayered structure. A flow channel member 116 that enables the permeated water to pass through is arranged as a spacer inside the bag-shaped reverse osmosis membrane 112. In the RO membrane element 108 with the above structure, raw water (salty water) flows into the mesh spacers 114 arranged between the reverse osmosis membranes 112 from the opening 104 located at one end (supply water side) (-Y-axis side). When a pressure greater than or equal to an osmotic pressure is applied on the raw water that flows into the mesh spacer 114, the water in the raw water permeates the reverse osmosis membrane 112 and flows into the flow channel member 116 arranged inside the bag-shaped reverse osmosis membrane 112. The water (filtered water) flows into the central pipe 110 from the flow channel member 116 and the filtered water is discharged from a hole (that communicates with the central pipe 110) provided at the center of the other end (+Y-axis side) (filtered water side) of the RO membrane element 108. Unfiltered concentrated water remaining in the mesh spacer 114 is discharged from the mesh spacer 114 from the other end.

Multiple RO membrane elements 108 are housed inside the pressure vessel 102. A pressure is applied on the RO membrane elements 108 by the raw water inside the pressure vessel 102 due to which the raw water is separated into the filtered water and the concentrated water in the reverse osmosis membrane 112. The central pipes 110 of two adjacent RO membrane elements 108 are communicably coupled by hollow joints 118 arranged at the tip ends of the central pipes 110. That is, the central pipes 110 of the adjacent RO membrane elements 108 are serially communicably coupled while being housed inside the pressure vessel 102 (see FIG. 15). Consequently, the filtered water obtained by filtration by the RO membrane element 108 is discharged out from the pressure vessel 102 from the integrally connected central pipes 110. The concentrated water discharged from a previous stage RO membrane element 108 is delivered to the next stage RO membrane element 108 where it is separated into filtered water and concentrated water. The concentrated water thus discharged from the last stage RO membrane element 108 is discharged out from the pressure vessel 102.

As shown in FIGS. 1 and 2, the reverse osmosis membrane element replacing device 10 according to the present embodiment mainly includes a stacker crane 12, a placement base 38 (not shown in FIG. 2), and a control unit 36. An outer shape of the stacker crane 12 is formed by a rectangular frame member 14 (first moving unit) that is movable in the horizontal direction in an upright posture in the vertical direction (Z-axis direction), and a load-bearing platform 22 (second moving unit) that has the placement base 38 arranged thereon and is attached to the frame member 14. The load-bearing platform 22 is movable in the up-and-down direction together with the placement base 38. The frame member 14 is arranged facing the openings 104 of the pressure vessels 102 of the reverse osmosis membrane module 100 (array surface: XZ plane). Moreover, a rail 16 on which the frame member 14 moves is arranged on a floor surface where the frame member 14 is arranged, with the longitudinal direction of the rail 16 aligned to the direction parallel to (first direction: X direction) the direction in which the pressure vessels 102 are horizontally arranged. Rotation of wheels 18 arranged on a lower end of the frame member 14 on the rail 16 enables movement of the frame member 14 from one end to the other end in the horizontal direction (X direction) of the array surface (XZ plane).

Consequently, even when the frame member 14 moves from one of the opening 104 to another opening 104 on the rail 16, the distance between the frame member 14 and the opening 104 facing the frame member 14 (array surface) remains constant. The rail 16 extends further beyond the position facing the end in the horizontal direction (X-axis direction) of the array surface (XZ plane) of the reverse osmosis membrane module 100 enabling movement of the frame member 14 up to a position facing a preparation area 122 (FIG. 2). That is, in the preparation area 122, the frame member 14 no more faces the array surface (XZ plane). When the frame member 14 is facing the preparation area 122, a new RO membrane element 108 can be easily loaded on the placement base 38, or a used RO membrane element 108 can be easily unloaded from the placement base 38.

Coaxial gear wheels (not shown) are engaged with the wheels 18, and the dynamic force of a running motor 20 that drives these gear wheels (not shown) enables the wheels 18 to rotate on the rail 16. A rotation direction and a rotation amount of the running motor 20 are controlled by the control unit 36. The frame member 14 can be moved to a desired position by rotating the wheels 18 in a desired direction for a desired rotation amount.

The load-bearing platform 22 is arranged sandwiching the frame member 14 in the thickness direction. That is, rotating contact rollers 24 arranged on the load-bearing platform 22 abut the frame member 14 from outer side thereby sandwiching the frame member 14 in the thickness direction (Y-axis direction). Moreover, the load-bearing platform 22 is suspended with a chain 26. The chain 26 is driven to move in the up-and-down direction (second direction: Z direction) by a lifting and lowering motor 28. A rotation
direction and a rotation amount of the lifting and lowering motor 28 are controlled by the control unit 36. The load-bearing platform 22 can be moved to any height by controlling an advancement direction and an advancement amount of the chain 2 6 according to a rotation direction and a rotation amount of the lifting and lowering motor 28.

As shown in FIG. 2, an insulation trolley 30 that supplies electric power to the stacker crane 12 is arranged on the floor surface, parallel to the rail 16. The electric power is continuously supplied to the stacker crane 12 and the control unit 36 (placement base 38) from the insulation trolley 30. Furthermore, a guide rail 32 is arranged horizontally and parallel to the rail 16, at a position from where a top edge of the frame member 14 passes, and rotating contact rollers 34 arranged at the top edge of the frame member 14 abut the guide rail 32. Accordingly, the frame member 14 is prevented from falling.
The control unit 36 controls a rotation direction and a rotation amount of the running motor 20, the lifting and lowering motor 28, and a driving motor 70 that drives driving units 58 and 72 that shall be described later. Furthermore, the control unit 36 moves the placement base 38 to a position facing any one of the openings 104 of the pressure vessels 102 arranged in an array, and inserts (pushes) the RO membrane element 108 riding on the placement base 38 into the pressure vessel 102, or removes the used RO membrane element 108 from the pressure vessel 102. In the present embodiment, the control unit 36 is arranged at the bottom of the stacker crane 12, but it can also be arranged separated from the stacker crane 12.

The control unit 36 retains positions where the opening 104 of each pressure vessel 102 constituting the reverse osmosis membrane module 100 and the placement base 38 face each other, and rotation amount information (information pertaining to a rotation angle based on a given rotational position, including an orbit component) obtained by converting into data by constant angle resolution of the rotation amounts of the running motor 20 and the lifting and lowering motor 28 when the placement base 38 is arranged in the preparation area 122. The control unit 36 continuously acquires the rotation amount information obtained by converting into data the current rotation amounts of the running motor 20 and the lifting and lowering motor 28. Furthermore, the control unit 36 appropriately selects the rotation amount information in accordance with the information pertaining to the position where the opening 104 of each pressure vessel 102 and the placement base 38 face each other and the position information of the preparation area 122.

When position information of a new destination opening 104 is entered using key operations, etc., the control unit 36 can calculate the difference between the rotation amount information corresponding to the current position information and the rotation amount information corresponding to the new destination position information, output an output signal corresponding to the rotation direction and the rotation amount corresponding to this difference to the running motor 20 and the lifting and lowering motor 28, respectively, to move the placement base 38 to a position facing the new destination opening 104.
The stacker crane 12, the guide rail 32, and the placement base 38 are designed to maintain a rigidity against a weight of the RO membrane element 108 and a reactive force generated by a frictional resistance between the RO membrane element 108 and the pressure vessel 102, when the placement base 38 inserts the RO membrane element 108 into the pressure vessel 102 or removes the used RO membrane element 108 from the pressure vessel 102 as explained later, enabling the insertion and removal of the RO membrane element 108 to be performed reliably.

FIG. 4 is a side view of the placement base according to the present embodiment. FIG. 5 is a plan view of the placement base according to the present embodiment. The placement base 38 is arranged on and fixed to the load-bearing platform 22 and serves as a base for placing the RO membrane element 108. The placement base 38 includes a brace-shaped first member 40 arranged on the load-bearing platform 22 in a standing manner, a second member 4 6 with a longitudinal direction thereof along the horizontal direction (X-axis direction), attached to the first member 40, and that can slide in the up-and-down direction (Z-axis direction) relative to the first member 40, and a third member 50 attached to the second member 4 6, and that can slide horizontally (X-axis direction) relative to the second member 46.
The first member 4 0 and the second member 4 6 are coupled via a lifting and lowering unit (third moving unit). The lifting and lowering unit is a linear guide that slides the second member 46 relative to the first member 40 in the up-and-down direction. The lifting and lowering unit includes a ball screw 42 attached to the first member 40 with a longitudinal direction thereof along the up-and-down direction, and that rotates about the rotation axis of the longitudinal direction; a motor 44 that causes the ball screw 42 to rotate; and a slider (not shown: integrated with the second member 46) attached to the second member 4 6 and threaded to the ball screw 42. Consequently, depending on a rotation direction and a rotation amount of the ball screw 42, the second member 4 6 can slide in the up-and-down direction relative to the first member 40. The second member 4 6 and the third member 50 are coupled via a horizontal moving unit (third moving unit). The horizontal moving unit is a linear guide that slides the third member 50 relative to the second member 46 horizontally. The horizontal moving unit includes a ball screw 48 attached to the second member 46 with a longitudinal direction thereof along the horizontal direction (X-axis direction) and that rotates about the rotation axis of the longitudinal direction, a motor (not shown) that causes the ball screw 48 to rotate, and a slider (not shown: integrated with the third member 50) attached to the third member 50 and threaded to the ball screw 48. Consequently, depending on a rotation direction and a rotation amount of the ball screw 48, the third member 50 can slide horizontally relative to the second member 46.

The third member 50 includes support units 52 that horizontally support the RO membrane element 108; the driving units 58 and 72 (see FIGS. 6 and 7) that push the RO membrane element 108 riding on the support units 52 into the pressure vessel 102, or remove the used RO membrane element 108 from the pressure vessel 102; and a relative position adjusting unit (not shown) that adjusts a misalignment in the relative positions of the opening 104 and the placement base 38 (the RO membrane element 108 riding on the support units 52) (a misalignment in the relative positions in the X-axis direction and the Z-axis direction), using a target (not shown) arranged at the opening 104 of the pressure vessel 102.
The relative position adjusting unit (not shown) is driven by the control unit 36 after the control unit 36 moves the placement base 38 to the position facing the opening 104 of the pressure vessel 102. The relative position adjusting unit can be arranged in, for example, the third member 50, and can have a structure that includes a camera (not shown) that has an optical axis facing in the direction from which the RO membrane element 108 is inserted into the pressure vessel 102 and that captures an image data of a subject as seen in that direction; and a relative position adjusting member (not shown) that recognizes, based on the image data, a target (not shown) that is arranged at a predetermined position at the opening 104 of the pressure vessel 102, and controls the rotation amounts of the motor 44 of the lifting and lowering unit and the motor (not shown) of the horizontal moving unit so that the target (not shown) is aligned with a predetermined position within the image.

Alternatively, the relative position adjusting unit can have a structure that includes a transmitting unit (not shown) that is arranged in the third member 50 and that emits a laser beam towards the target (not shown) arranged at a predetermined position of the opening 104 of the pressure vessel 102, a receiving unit (not shown) that receives the laser beam reflected from the target (not shown) attached to the third member 50, and the relative position adjusting member (not shown) that controls the rotation amounts of the motor 44 of the lifting and lowering unit and the motor (not shown) of the horizontal moving unit and causes the receiving unit (not shown) to receive the laser beam emitted by the transmitting unit (not shown).

In the former structure, adjustment needs to be made in advance so that the central axis of the pressure vessel 102 and the central axis of the RO membrane element 108 are aligned when the target (not shown) is aligned with the predetermined position (for example, the center) within the image. In the latter structure, adjustment needs to be made in advance so that the central axis of the pressure vessel 102 and the central axis of the RO membrane element 108 are aligned when the target (not shown) is, for example, a mirror having a high laser beam reflectivity and the receiving unit (not shown) receives a reflected light of the laser beam (or when the reflected light attains maximum intensity).

Thus, the misalignment in the relative positions of the placement base 38 after it is moved by the frame member 14 (first moving unit) and the load-bearing platform 22 (second moving unit) and the opening 104 are adjusted using the relative position adjusting unit (not shown) that performs adjustment using the target (not shown) arranged at the opening 104 (the target can be arranged at a place other than the opening 104). Consequently, the reverse osmosis membrane element can be reliably inserted into the opening 104, and as explained later, the RO membrane element 108 that is accommodated inside the pressure vessel 102 can be reliably removed. The relative position adjusting unit (not shown) performs fine adjustments of the placement base 38 in the X-axis direction and the Z-axis direction if there is a minor misalignment of positions; however, the control unit 36 can directly perform the control that is performed by the above-mentioned relative position adjusting member (not shown).

The support unit 52 includes rotating contact rollers 52a that are in rotating contact with a side surface of the RO membrane element 108. The support units 52 are arranged in such a way that positions of the rotating contact rollers 52a in rotation contact with the RO membrane element 108 follow the side surface of the RO membrane element 108. The support units 52 are arranged side-by-side in such a way that the RO membrane element 108 is supported by the rotating contact rollers 52a at two points (see FIG. 1) when viewed from an end face of the RO membrane element 108 (the support unit 52 can be arranged so that the rotating contact rollers 52a support the RO membrane element 108 at three points), and are arranged in the insertion direction (Y-axis direction) of the RO membrane element 108 into the pressure vessel 102. The rotation axes of the rotating contact rollers 52a are oriented in a direction perpendicular to a pushing direction (+Y-axis direction) of the RO membrane element 108 or a removing direction (-Y-axis direction) of the RO membrane element 108. The rotating contact rollers 52a rotate due to a frictional force between the rotating contact rollers 52a and the RO membrane element 108 when the RO membrane element 108 moves on the placement base 38 because of being pushed in by a rod 56. Consequently, the frictional resistance that occurs when the RO membrane element 108 is pushed in (drawn out) by the rod 56 is reduced. Instead of the rotating contact rollers 52a, a material that has a small frictional resistance with the RO membrane element 108 can be arranged.

FIG. 6 is a schematic diagram of a driving unit according to a first concrete example of the present invention. The driving unit 58 according to the first concrete example drives the rod 56 by chain driving. The third member 50 has an inner space 50a for arranging the driving unit 58, and a slit 50b (see FIG. 5) with a longitudinal direction thereof along the Y-axis and that opens into the inner space 50a at a position between the support units 52 that are on the +Z-axis side on a surface of the third member 50. The driving unit 58 according to the first concrete example basically includes a chain 64 that is stretched across a driving gear wheel 60 and a driven gear wheel 62, and a slider 66 that is anchored to the chain 64. The slider 66 passes through the slit 50b and is exposed to the outside. The rod 56 with a longitudinal direction thereof aligned to the insertion direction (+Y-axis direction) of the RO membrane element 108 is attached to the exposed part of the slider 66. The driving motor 70 (not shown in FIG. 6) of the driving unit 58 drives the driving gear wheel 60. The length between the driving gear wheel 60 and the driven gear wheel 62 (an advancement amount of the rod 56) is set at designing by taking into account a length of the pressure vessel 102 in the longitudinal direction and a length of the RO membrane element 108. With the above structure, the slider 66 and the rod 56 become slidable in the Y-axis direction by the rotation of the driving gear wheel 60 that is driven by the driving motor 70 (not shown in FIG. 6).

A slide guide 68 can be provided at the bottom of the slider 66 to improve the stability of the slider 66. When inserting (pushing in) the RO membrane element 108 into the pressure vessel 102 using the rod 56, an abutment plate 56a that is larger than an inner diameter of the central pipe 110 but smaller than the end of the RO membrane element 108 is arranged at the tip of the rod 56 on the +Y-axis side.
FIG. 7 is a schematic diagram of a driving unit according to a second concrete example of the present invention. The driving unit 72 according to the second concrete example drives the rod 56 by a linear guide, similar to the above-mentioned lifting and lowering unit and the horizontal moving unit. The driving unit 72 includes a ball screw 74 arranged in the inner space 50a of the third member 50 with a longitudinal direction thereof in the Y-axis direction and that rotates about the rotation axis of the longitudinal direction, the driving motor 70 that drives the ball screw 74, and a slider 76 that is threaded to the ball screw 74 and arranged on an extension line in the insertion direction of the RO membrane element 108 and that passes through the slit 50b and is exposed to the outside.. The rod 56 is attached to the exposed part of the slider 76 protruding from the slit 50b. An advancement amount of the driving unit 72 (a length of the ball screw 74) is set at designing by taking into account the length of the pressure vessel 102 in the longitudinal direction and the length of the RO membrane element 108.

The control unit 36 retains rotation amount information obtained by converting into data the rotation amount of the driving motor 70 when the rod 56 advances to the +Y-axis side to the fullest extent and the rotation amount of the driving motor 70 when the rod 56 advances to the -Y-axis side to the fullest extent required for driving the driving units 58 and 72 according to the first and second concrete examples, respectively. Furthermore, the control unit 36 constantly acquires the rotation amount information obtained by converting to data the current rotation amount of the driving motor 70. Moreover, the control unit 36 extracts the respective rotation amount information corresponding to position information
corresponding to when the rod 56 advances to the -Y-axis side to the fullest extent and position information corresponding to when the rod 56 advances to the +Y-axis side to the fullest extent.
When the position information corresponding to when the rod 56 advances to the +Y-axis side to the fullest extent or the position information corresponding to when the rod 56 advances to the -Y-axis side to the fullest extent is input by key operations, etc., the control unit 36 calculates a difference between the rotation amount information corresponding to the input position information and the current rotation amount information of the driving motor 70, and outputs to the driving motor 70 corresponding output signals for the rotation direction and the rotation amount according to the difference, causing the rod 56 to move to a predetermined position. That is, the control unit 36 pushes the RO membrane element 108 riding on the placement base 38 into the pressure vessel 102, or as explained later, draws out the RO membrane element 108 from the pressure vessel 102.

FIG. 8 is a drawing for explaining an operation (before pushing in) of the reverse osmosis membrane element replacing device according to the present embodiment. FIG. 9 is a drawing for explaining an operation (after pushing in) of the reverse osmosis membrane element replacing device according to the present embodiment. The operations of the reverse osmosis membrane element replacing device 10 according to the present embodiment are explained below. First, the operation of insertion (pushing in) of the RO membrane element 108 into the pressure vessel 102 is explained below.

At the startup of the reverse osmosis membrane element replacing device 10, the stacker crane 12 is positioned facing the preparation area 122 and the placement base 38 is at the lowermost position. Furthermore, the driving motor 70 of the driving units 58 and 72 arranged on the placement base 38 has the rotation amount corresponding to when the rod 56 is slid to the -Y-axis side to the fullest extent.
In the preparation area 122, a worker first loads the RO membrane element 108 on the placement base 38 (support unit 52) using a lift, etc. (see FIG. 1). At this point, the abutment plate 56a arranged at the tip of the rod 56 on the +Y-axis side is facing or abutting the end of the RO membrane element 108 on the -Y-axis side.

The worker performs key operations, etc., to input in the control unit 36, information pertaining to the position of the opening 104 of the pressure vessel 102 into which the RO membrane element 108 is to be inserted. The control unit 36 outputs the output signal to the running motor 20 and the lifting and lowering motor 28 such that the placement base 38 is positioned facing the target opening 104. After the placement base 38 is moved to the position facing the target opening 104, the control unit 36 drives the relative position adjusting unit (not shown) to perform minute adjustments of the placement base 38 in the X-axis direction and the Z-axis direction so that the central axis of the RO membrane element 108 and the central axis of the pressure vessel 102 are aligned (FIG. 8) .

The worker then inputs in the control unit 36 by key operations, etc., the position information corresponding to when the rod 56 advances to the +Y-axis side to the fullest extent. Thereupon, the control unit 36 outputs the output signal to the driving motor 70 of the driving units 58 and 72, and drives the driving motor 70 to move the rod 56 to the +Y-axis side. Consequently, the rod 56 moves to the +Y-axis side (pressure vessel 102 side) and pushes the RO membrane element 108 to the pressure vessel 102 side. When the rod 56 reaches the position of maximum advancement to the +Y-axis side, the driving action of the driving motor 70 is stopped (see FIG. 9).

The worker then inputs in the control unit 36 the position information corresponding to when the rod 56 advances to the -Y-axis side to the fullest extent. In response, the control unit 36 outputs the output signal to the driving motor 70 to cause the rod 56 to be moved to the -Y-axis side. Thereupon, the worker inputs in the control unit 36 the position information pertaining to the position at which the placement base 38 faces the preparation area 122. In response, the control unit 36 outputs the output signal to the running motor 20 and the lifting and lowering motor 28 to move the stacker crane 12 (the frame member 14 and the load-bearing platform 22) to the position at which it faces the preparation area 122.
Because multiple RO membrane elements 108 are housed in one pressure vessel 102, the above process is repeated to insert subsequent RO membrane elements 108 into the pressure vessel 102. One joint 118 (see FIG. 15) is fitted beforehand at each of the two ends of the central pipe 110 in the longitudinal direction thereof on the +Y-axis side of a new RO membrane element 108 that is to be inserted. When inserting a new RO membrane element 108 into the pressure vessel 102 in which an RO membrane element 108 was previously inserted, the joint 118 fits into the end of the central pipe 110 on the -Y-axis side of the RO membrane element 108 that was previously inserted (see FIG. 15), and the rod 56 pushes into the pressure vessel 102 both the RO membrane element 108 that was previously inserted and the new RO membrane element 108 that is currently being inserted. This operation is repeated until the pressure vessel 102 is packed with the RO membrane elements 108. Once a predetermined number of the RO membrane elements 108 are housed inside one pressure vessel 102, the operation is repeated for another pressure vessel 102.

Thus, in the reverse osmosis membrane element replacing device 10 according to the present embodiment, the stacker crane 12 reliably moves the RO membrane element 108 to the position facing the opening 104 of any pressure vessel 102 in the reverse osmosis membrane module 100 in which the pressure vessels 102 are arranged in an array in the X-axis direction and the Z-axis direction, without having to rely on manual labor. Furthermore, the relative position adjusting unit (not shown) of the reverse osmosis membrane element replacing device 10 corrects, without relying on manual labor, any misalignment in the positions of the placement base 38 and the opening 104 so that the central axis of the RO membrane element 108 and the central axis of the pressure vessel 102 are aligned, enabling, without relying on manual labor, the RO membrane element 108 to be inserted into (pushed into) the pressure vessel 102 by the driving in the +Y-axis direction of the rod 56 arranged on the placement base 38. Consequently, the RO membrane element 108 can be inserted into the reverse osmosis membrane module 100 swiftly and safely.

FIGS. 10A and 10B are a set of schematic diagrams of a driving unit according to a third concrete example of the present invention. FIG. 10A is a schematic diagram of the driving unit when retracted and FIG. 10B is a schematic diagram of the driving unit when extended. FIG. 11 is a drawing for explaining an operation (during retraction) of the driving unit according to the third concrete example. FIG. 12 is a drawing for explaining an operation (during a first step of extension) of the driving unit according to the third concrete example. FIG. 13 is a drawing for explaining an operation (during a second step of extension) of the driving unit according to the third concrete example.

In the driving units 58 and 72 according to the first and second concrete examples, because the number of the RO membrane elements 108 being pushed in by the rod 56 increases every time the operation of insertion of the RO membrane element 108 into the pressure vessel 102 is repeated, the frictional resistance between the RO membrane element 108 and the pressure vessel 102 increases, increasing the load on the driving units 58 and 72. To solve this issue, in the present concrete example, to enable the RO membrane element 108 loaded on the placement base 38 to be pushed deep into the pressure vessel 102 from the very start, a multi-stage hydraulic cylinder 78 is employed in which telescopic cylinder rods are used.

The multi-stage hydraulic cylinder 78 according to the present embodiment basically has a structure that includes a cylinder 80 that has an oil chamber (not shown) internally, a first rod 82 that extends from the cylinder 80 to the +Y-axis side due to inflow of hydraulic oil into the oil chamber, and a second rod 84 that extends from the first rod 82 further to the +Y-axis side due to further inflow of the hydraulic oil. The multi-stage hydraulic cylinder 78 is connected to a spare tank (not shown) containing the hydraulic oil through a pump (not shown). The pump (not shown) is capable of performing forward rotation and reverse rotation to supply the hydraulic oil from the spare tank (not shown) to the multi-stage hydraulic cylinder 78 at a constant pressure and to remove the hydraulic oil inside the multi-stage hydraulic cylinder 78 by suction at a constant suction power (pressure) and supplies into a preparation tank. Accordingly, the multi-stage hydraulic cylinder 78 can extend in the +Y-axis direction at a constant force due to the forward rotation, or retract in the -Y-axis direction at a constant force due to the reverse rotation of the pump (not shown). The pump (not shown) is driven by a driving signal output by the control unit 36.

As shown in FIGS. 11 to 13, the multi-stage hydraulic cylinder 78 is arranged on the -Y-axis side of the support unit 52 of the third member 50 of the placement base 38. The tip of the second rod 84 abuts the end of the RO membrane element 108 on the -Y-axis side (see FIG. 11). When the hydraulic oil is fed by the pump (not shown) into the cylinder 80, the first rod 82 and the second rod 84 extend from the cylinder 80 in the +Y-axis direction (see FIG. 12), and after the first rod 82 has extended from the cylinder 80 to the fullest extent, the second rod 84 extends from the first rod 82 in the +Y-axis direction (see FIG. 13). With the extension of both the first rod 82 and the second rod 84, the RO membrane element 108 is inserted into the pressure vessel 102.

A winding mechanism (not shown) of a wire (not shown) and an encoder (not shown) that converts an advancement amount of the wire (not shown) into data are fitted on the cylinder 80 of the multi-stage hydraulic cylinder 78 (can be the third member 50 instead of the cylinder 80). A tip end of the wire (not shown) is fitted on a tip end of the second rod 84. The encoder (not shown) outputs information pertaining to the advancement amount of the wire (not shown) to the control unit 36. Consequently, the control unit 36 retains information pertaining to the advancement amount of the wire (not shown) when the multi-stage hydraulic cylinder 78 is retracted to the fullest extent and when the multi-stage hydraulic cylinder 78
is extended to the fullest extent, as well as information pertaining to the current advancement amount.

Accordingly, the control unit 36 can control the multi-stage hydraulic cylinder 78, which is the driving unit according to the third concrete example, similar to the driving units 58 and 72 according to the first and second concrete examples.

With the above structure, the RO membrane element 108 can be pushed deeper inside the pressure vessel 102 as compared to when pushed by the driving units 58 and 72 according to the first and second concrete examples. Consequently, a situation where the RO membrane element 108 that is pushed in later pushes against the RO membrane element 108 that is pushed in before can be mitigated. Consequently, even if there is an increase in the number of the RO membrane elements 108 to be loaded, an increase in the frictional resistance during pushing corresponding to the number of the RO membrane elements 108 to be loaded can be suppressed. Furthermore, when the rod 56 is in a contracted state, the first rod 82 and the second rod 84 are housed inside the cylinder 80, resulting in a reduction in a length of the multi-stage hydraulic cylinder 78 in the longitudinal direction (Y-axis direction). Consequently, an area occupied by the reverse osmosis membrane element replacing device 10 can be reduced. Furthermore, because the actual advancement amount of the second rod 84 can be detected by the encoder (not shown), the insertion and the later-explained removal of the RO membrane element 108 can be performed reliably.

FIG. 14 is a set of drawings showing a removal process of the RO membrane element using a coupling unit according to the first concrete example. Not only can the reverse osmosis membrane element replacing device 10 according to the present embodiment insert the RO membrane element 108 into the pressure vessel 102 but also remove the used RO membrane element 108 from the pressure vessel 102 using the driving units according to the first to third concrete examples. In this case, a coupling unit 86 is arranged at a tip end of the rod 56 (the coupling unit can be arranged at a tip end of the second rod 84, similar to the rod 56). The coupling unit 86 includes an internally hollow elastic member and an injection pipe 88 that communicates with the hollow portion of coupling unit 86. The coupling unit 86 expands when pneumatic pressure or hydraulic pressure is applied within the hollow portion of the coupling unit 86 via the injection pipe 88, and an outer wall of the coupling unit 86 press-fits against an inner wall of the central pipe 110. Consequently, the rod 56 couples with the central pipe 110 owing to a crimp force (frictional force) of the coupling unit 86 against the central pipe 110.

The coupling unit 8 6 is designed in such a way that, prior to the application of the pneumatic pressure or the hydraulic pressure, an outer diameter thereof is smaller than an inner diameter of the central pipe 110 to enable the coupling unit 86 to pass through the central pipe 110, but when the pneumatic pressure or the hydraulic pressure is applied when not inserted into the central pipe 110, the outer diameter thereof becomes greater than the inner diameter of the central pipe 110, enabling the coupling device to press-fit against the inner wall of the central pipe 110. The injection pipe 88 is connected to a compressor (not shown) that supplies air or fluid at a constant pressure. The control unit 36 exerts control to drive or stop the compressor (not shown).

The removal process of the RO membrane element 108 from the pressure vessel 102 using the above-explained coupling unit 86 is explained below. As shown in the upper drawing of FIG. 14, the control unit 36 causes the rod 56 to advance in the +Y-axis direction to insert the coupling unit 86 prior to the application of
the pneumatic pressure or the hydraulic pressure into the central pipe 110. Thereafter, as shown in the middle drawing of FIG. 14, the control unit 36 drives the compressor (not shown) to supply air or fluid, such as oil, into the hollow portion of the coupling unit 86 at a constant pressure, causing the coupling unit 86 to expand. Consequently, an outer wall of the coupling unit 86 press-fits against the inner wall of the central pipe 110, and the rod 56 and the central pipe 110 are coupled owing to the crimp force (frictional force). Thereafter, as shown in the bottom drawing of FIG. 14, the control unit 36 exerts control to pull the rod 56 in the -Y-axis direction with the coupling unit 86 press-fitted against the central pipe 110.

Consequently, owing to the frictional force between the coupling unit 86 and the central pipe 110, the RO
membrane element 108 is pulled in the -Y-axis direction along with the coupling unit 86, and is pulled out of the pressure vessel 102, and placed on the support unit 52 of the placement base 38 (see FIG. 4).
Upon stoppage of the driving of the compressor (not shown) by the control unit 36, application of the pneumatic pressure or the hydraulic pressure on the coupling unit 86 is terminated resulting in the termination of press-fitting of the coupling unit 86 against the central pipe 110. Furthermore, the rod 56 can be pulled out from the RO membrane element 108 riding on the placement base 38 by further moving the rod 56 in the -Y-axis direction. However, in view of safety at the time of movement of the placement base 38 by the stacker crane 12, it is preferable that the rod 56 be pulled out from the RO membrane element 108 after the placement base 38 is moved to the preparation area 122 by the control unit 36.
FIG. 15 is a schematic diagram showing a case in which the RO membrane element is removed using a coupling unit according to the second concrete example. FIG. 16 is a cross-sectional view taken along a line A-A of FIG. 15. FIG. 17 is a cross-sectional view taken along a line B-B of FIG. 15. FIG. 18 is a view along an arrow C of FIG. 15 and shows a state when the coupling unit has gone past projecting members. FIG. 19 is a view along the arrow C of FIG. 15 and shows an arrangement during removal of the RO membrane element by turning the coupling unit after the coupling unit has gone past the projecting members.

As shown in FIG. 15, the RO membrane elements 108 are coupled within the pressure vessel 102 (not shown in FIG. 15) via the joint 118. The joint 118 is a hollow member capable of fitting into the central pipes and connects two adjoining central pipes. In the present embodiment, the RO membrane element 108 is removed along with the joint 118 using a coupling unit 90 that is attached to a tip end (abutment plate 56a) of the rod 56 and projecting members 120 provided in the joint 118.

As shown in FIG. 15, the coupling unit 90 is a cylindrical member designed in such a way that an outer diameter thereof is smaller than an inner diameter of the joint 118, and is attached to the tip end of the rod 56 so as to be coaxial with the rod 56. Four grooves 92 with a longitudinal direction thereof along the Y-axis are formed on an outer surface of the coupling unit 90, making the coupling unit 90 four-fold symmetrical about the central axis. As shown in FIG. 16, between two adjoining grooves 92 of the coupling unit 90, a tongue 94 that engages with (abuts) the projecting member 120 is formed.

Meanwhile, as shown in FIG. 17, the joint 118 has the projecting members 120 that project inward from an inner wall thereof. The projecting member 120 has a longitudinal direction along the Y-axis similar to the groove 92, and is designed to be narrower than a width of the groove 92 and have a height that is shorter than a depth of the groove 92; the projecting members 120 are arranged forming a four-fold symmetry about a central axis of the joint 118. In the present embodiment, the rod 56 has an outer diameter that is smaller than the inner diameter of the central pipe 110, and is designed so as not to come out of the groove 92 as viewed from the direction (Y-axis direction) in FIG. 16. The rod 56 can rotate about the central axis along the longitudinal direction. The control of the rotation of the rod 56 is performed by the control unit 36. Consequently, as shown in FIG. 18, if a rotation angle of the rod 56 is adjusted so that the projecting members 120 and the grooves 92 face each other, the coupling unit 90 can get past the projecting members 120 without any interference between the projecting members 120 and the coupling unit 90. Furthermore, as shown in FIG. 19, if the rotation angle of the rod 56 is adjusted so that the projecting members 120 and the tongues 94 face each other, the tongues 94 and the projecting members 120 engage with (abut) each other.

The removal process of the RO membrane element 108 using the coupling unit 90 and the projecting member 120 is as follows. The control unit 36 causes the rod 56 with the coupling unit 90 attached at the tip end thereof to move in the +Y-axis direction and the coupling unit 90 and the rod 56 to be inserted into the central pipe 110. At this time, the rotation angle of the rod 56 is adjusted by the control unit 36 so that the arrangement of the coupling unit 90 and the projecting members 120 is as shown in FIG. 18. Thereafter, the rod 56 is further advanced inward into the central pipe 110 until the coupling unit 90 has gone past the projecting members 120 of the joint 118 completely. Thereafter, the control unit 36 rotates the rod 56 so that the arrangement of the coupling unit 90 and the projecting members 120 becomes as shown in FIG. 19, and exerts control so as to cause the rod 56 to move in the -Y-axis direction.

Consequently, the tongues 94 of the coupling unit 90 engage with (abut) the projecting members 120, and the coupling unit 90 can pull the projecting members 120 in the -Y-axis direction. Consequently, the RO membrane element 108 that is closer to the -Y-axis side than the coupling unit 90 is pulled in the -Y-axis direction along with the joint 118, removed from the pressure vessel 102, and placed on the support unit 52 of the placement base 38. When the frictional force between the RO membrane element 108 that is closer to the +Y-axis side than the coupling unit 90 and the joint 118 is smaller than the frictional force between the RO membrane element 108 and the pressure vessel 102, the attachment between the RO membrane element 108 and the joint 118 is terminated, and the RO membrane element stays in the pressure vessel 102.

In the present embodiment also, after the RO membrane element 108 is removed from the pressure vessel 102 and placed on the placement base 38, the rod 56 and the coupling unit 90 can be removed from the RO membrane element 108 by rotating the rod 56 so that the arrangement of the coupling unit 90 and the projecting members 120 becomes as shown in FIG. 18 and further moving the rod 56 in the -Y-axis direction. However, taking safety into account, it is preferable that the rod 56 and the coupling unit 90 be removed after the placement base 38 is moved to the preparation area 122. Although four grooves 92 and four projecting members 120 are arranged in the coupling unit 90, any number of grooves 92 and projecting members 120 greater than or equal to one can be arranged. Although a four-fold symmetry is shown here, the arrangement of the grooves 92 and the projecting members 120 can show any rotational symmetry or no rotational symmetry at all.

The removal process of the RO membrane element 108 by the reverse osmosis membrane element replacing device 10 according to the present embodiment using the coupling unit 86 according to the first concrete example or the coupling unit 90 according to the second concrete example is explained below. At the startup of the reverse osmosis membrane element replacing device 10, similar to the above-explained step of insertion of the RO membrane element 108, the coupling unit 8 6 or the coupling unit 90 is attached to the rod 56 placed on the placement base 38. Thereafter, similar to the above-explained insertion process of the RO membrane element 108, the placement base 38 is placed at a position facing the removal target opening 104 of the pressure vessel 102. The RO membrane element 108 is thereafter removed from the pressure vessel 102 using the coupling unit 86 or the coupling unit 90, the placement base 38 is moved to the preparation area 122, and the used RO membrane element 108 riding on the placement base 38 is removed by the worker by using a lift, etc. Because multiple RO membrane elements 108 are accommodated inside the pressure vessels 102 as explained above, the above process is repeated until all the RO membrane elements 108 are removed.

Thus, the reverse osmosis membrane element replacing device 10 according to the present embodiment
is capable of removing the RO membrane element 108 from the reverse osmosis membrane module 100 swiftly and safely, similar to the insertion process of the RO membrane element 108. Therefore, by performing the above-explained insertion process of the RO membrane element 108 after the above-explained removal process of the RO membrane element 108, the used RO membrane element 108 inside the pressure vessel 102 can be replaced with a new RO membrane element 108.

FIG. 20 is a drawing of a loading unit according to the first concrete example. FIG. 21 is a drawing of a loading unit according to the second concrete example. FIG. 22 is a drawing of a loading unit according to the third concrete example. As shown in FIG. 20, the loading unit according to the first concrete example includes a conveyor belt 96. The conveyor belt 96 is arranged in the region where the support unit 52 of the third member 50 is arranged and has a horizontal transport direction. A plurality of the RO membrane elements 108 can be arranged on the conveyor belt 96. The RO membrane element 108 that is facing the multi¬stage hydraulic cylinder 78 serving as the driving unit from the +Y-axis direction is inserted into the pressure vessel 102 by being pushed in the +Y-axis direction by the extension of the multi-stage hydraulic cylinder 78 in the +Y-axis direction. Thereafter, the multi-stage hydraulic cylinder 78 is retracted, the conveyor belt 96 is driven and a new RO membrane element 108 is transported to face the multi-stage hydraulic cylinder 78 from the +Y-axis direction. By repeating the above pushing-in process and transporting process, the RO membrane elements 108 can be successively inserted into the pressure vessel 102.

As shown in FIG. 21, the loading unit according to the second concrete example includes multi-stage cartridges 98. The multi-stage cartridges 98 are vertically arranged in the region where the support unit 52 of the third member 50 is arranged and is movable in the up-and-down direction. The cartridges 98 are open on the surfaces facing the Y-axis; the surface of the cartridges 98 facing the +Y-axis faces the pressure vessel 102, and the surface of the cartridges 98 facing the -Y-axis faces the multi-stage hydraulic cylinder 78. Each cartridge 98 has the RO membrane element 108 arranged therein. With this structure, the RO membrane element 108 arranged in the cartridge 98 at the bottommost stage is brought to face the multi-stage hydraulic cylinder 78, and pushed into the pressure vessel 102 by the multi-stage hydraulic cylinder 78. Thereafter, the multi-stage hydraulic cylinder 78 is retracted, the cartridge 98 is lowered by one stage to bring the RO membrane element 108 arranged in the next cartridge 98 to face the multi¬stage hydraulic cylinder 78, and the pushing-in process and a one-stage lowering process of the cartridge 98 are repeated.

A loading unit according to the third concrete example shown in FIG. 22 is similar to the loading unit according to the second concrete example except that a movement direction of the cartridges 98 is in the opposite direction. In the reverse osmosis membrane element replacing device 10 according to the present ' mbodiment, the RO membrane elements 108 can be successively inserted into the pressure vessel 102 by the loading units according to the first to third concrete examples, and a process speed can be improved. Furthermore, not only can the multi-stage hydraulic cylinder 78 according to the third concrete example be used as the driving unit but also the driving unit 58 according to the first concrete example and the driving unit 72 according to the second concrete example can be used as the driving unit.

According to an aspect of the present invention, a reverse osmosis membrane element replacing device that replaces a reverse osmosis membrane element from a reverse osmosis membrane module that includes a plurality of pressure vessels arranged in a stack, and into which the reverse osmosis membrane element, which is formed by a rolled up reverse osmosis membrane, is fitted, with openings of the pressure vessels, through which the reverse osmosis membrane element is inserted, facing in the same direction and arranged in the same plane, includes a placement base that can be positioned facing any one of the opening and carries the reverse osmosis membrane element with an end thereof oriented in a pushing direction of the reverse osmosis membrane element from the opening toward the pressure vessel; a first moving unit that moves the placement base in a first direction that is perpendicular to the pushing direction; a second moving unit that moves the placement base in the pushing direction and a second direction that is perpendicular to the first direction; a driving unit that pushes the reverse osmosis membrane element riding on the placement base into the pressure vessel by moving a rod facing the opening to the pressure vessel side and removes the reverse osmosis membrane element accommodated inside the pressure vessel by moving the rod that is abutting the reverse osmosis membrane element inside the pressure vessel via a coupling unit in a direction away from the pressure vessel; and a control unit that controls movement amounts of the first moving unit and the second moving unit so as to cause the reverse osmosis membrane element riding on the placement base to face any of the openings and drives the driving unit.

With the above structure, the reverse osmosis membrane element can be replaced swiftly and safely in the reverse osmosis membrane module.

The placement base includes a third moving unit that is capable of adjusting a position of the reverse osmosis membrane element placed on the placement base in the first direction and the second direction, and a relative position adjusting unit that adjusts relative positions of the placement base and the opening using a target arranged in the opening.
With the above structure, a misalignment in the relative positions of the placement base after it is moved using the first moving unit and the second moving unit, and the opening can be adjusted using a relative position adjusting unit that adjusts the positions using the target arranged at the opening. Consequently, the reverse osmosis membrane element can be reliably inserted in the opening and the reverse osmosis membrane element fitted in the pressure vessel can be reliably removed.

The reverse osmosis membrane element includes a central pipe that has the reverse osmosis membrane wrapped around a periphery thereof and that discharges filtered water filtered by the reverse osmosis membrane, the rod is insertable into the central pipe, the coupling unit includes a hollow elastic member that is arranged at a tip end of the rod, is insertable into the central pipe, and enables coupling of the central pipe and the rod by press-fitting with the central pipe owing to expansion caused by pneumatic pressure or hydraulic pressure, and the control unit enables removal of the reverse osmosis membrane element from the pressure vessel by exerting control so as to pull the rod from the pressure vessel after enablement of control over pulling the rod from the pressure vessel via the driving unit and coupling the central pipe and the rod through the coupling unit.

With the above structure, the reverse osmosis membrane element housed in the pressure vessel can be removed with a simple structure.

A plurality of the reverse osmosis membrane elements can be accommodated into the pressure vessel, and the reverse osmosis membrane elements are arranged inside the pressure vessel in a series, the reverse osmosis membrane element includes a central pipe that has the reverse osmosis membrane wrapped around a periphery thereof and that discharges filtered water filtered by the reverse osmosis membrane, adjacent reverse osmosis membrane elements inside the pressure vessel are coupled by joining the central pipes of the reverse osmosis membrane elements with a hollow joint that fits into the central pipes of the reverse osmosis membrane elements, a projecting member that projects from an inner wall of the joint is arranged on the inner wall, the rod is insertable into the central pipe, the coupling unit is arranged at a tip end of the rod and has a shape that enables engagement with the projecting member, and the control unit enables removal of the reverse osmosis membrane element along with the joint from the pressure vessel by exerting control so as to pull the rod from the pressure vessel after enablement of control over pulling of the rod from the pressure vessel via the driving unit and engagement of the coupling unit with a projecting member.

With the above structure, the reverse osmosis membrane element housed in the pressure vessel can be removed with a simple structure.

The driving unit includes a telescopic mechanism with the rod serving as a tip end thereof and that is a multi-stage hydraulic cylinder capable of extending and retracting in an insertion direction of the reverse osmosis membrane element.

With the above structure, the driving unit can push the reverse osmosis membrane element deep into the interior of the pressure vessel and when the rod retracts, the driving unit is drawn in. Consequently, an area occupied by the reverse osmosis membrane element replacing device can be reduced.

An encoder that calculates an advancement amount of the rod is arranged in the driving unit.
With the above structure, because the actual advancement amount of the rod can be detected, the insertion and removal of the reverse osmosis membrane element can be reliably performed.

A loading unit with a plurality of the reverse osmosis membrane elements loaded thereon is arranged on the placement base, and the loading unit is capable of loading a new reverse osmosis membrane element on the placement base after the driving unit inserts the reverse osmosis membrane element riding on the placement base into the pressure vessel.

With the above structure, operation efficiency can be improved because the reverse osmosis membrane elements can be successively inserted into the pressure vessels.

In a reverse osmosis membrane filtration apparatus, the above reverse osmosis membrane element replacing device is arranged at a position facing the openings of the reverse osmosis membrane module.

With the above structure, in the reverse osmosis membrane filtration apparatus, the reverse osmosis membrane element fitted into the pressure vessel can be swiftly and safely replaced.

According to a reverse osmosis membrane element replacing device and a reverse osmosis membrane filtration apparatus having the above features, the thus far extremely laborious work of replacing a reverse osmosis membrane element in a pressure vessel can be automated, enabling swift and safe accomplishment of work. Furthermore, the reverse osmosis membrane element can be automatically inserted into the pressure vessel or a used reverse osmosis membrane element housed in the pressure vessel can be removed even if the pressure vessel is located at a height.

Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.

We Claim:

1. A reverse osmosis membrane element replacing device that replaces a reverse osmosis membrane element from a reverse osmosis membrane module that includes a plurality of pressure vessels arranged in a stack, and into which the reverse osmosis membrane element, which is formed by a rolled up reverse osmosis membrane, is fitted, with openings of the pressure vessels, through which the reverse osmosis membrane element is inserted, facing in the same direction and arranged in the same plane, the reverse osmosis membrane element replacing device comprising:

a placement base that can be positioned facing any one of the opening and carries the reverse osmosis membrane element with an end thereof oriented in a pushing direction of the reverse osmosis membrane element from the opening toward the pressure vessel;

a first moving unit that moves the placement base in a first direction that is perpendicular to the pushing direction;

a second moving unit that moves the placement base in the pushing direction and a second direction that is perpendicular to the first direction;

a driving unit that pushes the reverse osmosis membrane element riding on the placement base into the pressure vessel by moving a rod facing the opening to the pressure vessel side and removes the reverse osmosis membrane element accommodated inside the pressure vessel by moving the rod that is abutting the reverse osmosis membrane element inside the pressure vessel via a coupling unit in a direction away from the pressure vessel; and

a control unit that controls movement amounts of the first moving unit and the second moving unit so as to cause the reverse osmosis membrane element riding on the placement base to face any of the openings and drives the driving unit.

2. The reverse osmosis membrane element replacing device according to Claim 1, wherein the placement base includes

a third moving unit that is capable of adjusting a position of the reverse osmosis membrane element placed on the placement base in the first direction and the second direction, and

a relative position adjusting unit that adjusts relative positions of the placement base and the opening using a target arranged in the opening.

3. The reverse osmosis membrane element replacing device according to Claim 1 or 2, wherein the reverse osmosis membrane element includes a central pipe that has the reverse osmosis membrane wrapped around a periphery thereof and that discharges filtered water filtered by the reverse osmosis membrane, the rod is insertable into the central pipe, the coupling unit includes a hollow elastic member that is arranged at a tip end of the rod, is insertable into the central pipe, and enables coupling of the central pipe and the rod by press-fitting with the central pipe owing to expansion caused by pneumatic pressure or hydraulic pressure, and

the control unit enables removal of the reverse osmosis membrane element from the pressure vessel by exerting control so as to pull the rod from the pressure vessel after enablement of control over pulling the rod from the pressure vessel via the driving unit and coupling the central pipe and the rod through the coupling unit.

4. The reverse osmosis membrane element replacing device according to Claim 1 or 2, wherein

a plurality of the reverse osmosis membrane elements can be accommodated into the pressure vessel, and the reverse osmosis membrane elements are arranged inside the pressure vessel in a series,

the reverse osmosis membrane element includes a central pipe that has the reverse osmosis membrane wrapped around a periphery thereof and that discharges filtered water filtered by the reverse osmosis membrane,

adjacent reverse osmosis membrane elements inside the pressure vessel are coupled by joining the central pipes of the reverse osmosis membrane elements with a hollow joint that fits into the central pipes of the reverse osmosis membrane elements,

a projecting member that projects from an inner wall of the joint is arranged on the inner wall,
the rod is insertable into the central pipe,

the coupling unit is arranged at a tip end of the rod and has a shape that enables engagement with the projecting member, and

the control unit enables removal of the reverse osmosis membrane element along with the joint from the pressure vessel by exerting control so as to pull the rod from the pressure vessel after enablement of control over pulling of the rod from the pressure vessel via the driving unit and engagement of the coupling unit with a projecting member.

5. The reverse osmosis membrane element replacing device according to any one of Claims 1 to 4, wherein the driving unit includes a telescopic mechanism with the rod serving as a tip end thereof and that is a multi-stage hydraulic cylinder capable of extending and retracting in an insertion direction of the reverse osmosis membrane element.

6. The reverse osmosis membrane element replacing device according to Claim 5, wherein an encoder that calculates an advancement amount of the rod is arranged in the driving unit.

7. The reverse osmosis membrane element replacing device according to any one of Claims 1 to 6, wherein a loading unit with a plurality of the reverse osmosis membrane elements loaded thereon is arranged on the placement base, and the loading unit is capable of loading a new reverse osmosis membrane element on the placement base after the driving unit inserts the reverse osmosis membrane element riding on the placement base into the pressure vessel.

8. A reverse osmosis membrane filtration apparatus includes the reverse osmosis membrane element replacing device according to any one of Claims 1 to 7 arranged at a position facing the openings of the reverse osmosis membrane module.