Claims:1. A peristaltic device (100), comprising:
a channel (102);
a flexible membrane (104) disposed along an inner surface of the channel (102) and adapted to hold a substance to be transported via the channel (102);
a helical member (106) comprising one or more ridges and adapted to rotate about a selected axis (120) of the channel (102), wherein a distance between adjacent ridges of the helical member (106) is selected such that the helical member (106) constricts the flexible membrane (102) at one or more points to lock the substance in one or more pockets within the flexible membrane (104), and displaces the locked substance in the linear direction along the channel (102) upon rotation of the helical member (106).
2. The peristaltic device (100) as claimed in claim 1, further comprising:
a first gear (108) operatively coupled to the helical member (106);
a second gear (110) disposed in an engaged position with the first gear (108);
a motor (112) operatively coupled to the second gear (112) and configured to rotate the second gear (110) at a selected rate of rotations per minute, wherein a rotation of the second gear (112) rotates the first gear (110), which causes a corresponding rotation of the helical member (106) about the selected axis (120) of the channel (102) to displace a constant amount of the substance (114) during every full rotation of the helical member (106).
3. The peristaltic device (100) as claimed in claim 1, wherein the channel (102) comprises of an inlet port (116) adapted to allow entry of the substance into the channel (102) and an outlet port (118) adapted to propel the substance out of the channel (102) via the flexible membrane (104).
4. The peristaltic device (100) as claimed in claim 1, wherein the flexible membrane (104) is fastened to the channel (102) so as to form one or more columns that hold the substance without allowing the substance to move between the columns.
5. The peristaltic device (100) as claimed in claim 1, wherein the flexible membrane (104) comprises one or more conduits having one or more cross-sectional areas to transport varying amounts of the substance through the channel (102).
6. The peristaltic device (100) as claimed in claim 1, wherein the helical member (106) is a helical screw such that the distance between adjacent ridges of the helical member (106) is constant.
7. The peristaltic device (100) as claimed in claim 1, wherein the channel (102) is composed of a rigid material, the flexible membrane (104) is composed of an elastic material, and wherein the helical member (106) is composed of a selected material.
8. The peristaltic device (100) as claimed in claim 7, wherein the rigid material comprises one or more of a metal, a polymer, a polypropylene and a polyvinyl material, the elastic material comprises one or more of an elastomer, a silicone, and a polyisoprene material, and wherein the selected material comprises one or more of a polyamide, nylon, and steel.
9. The peristaltic device (100) as claimed in claim 1, wherein the peristaltic device (100) comprises one or more of a medical infusion pump, a heart-lung device, an acid dispenser, a biotechnology device, an ultrafiltration device, and an industrial pump.
10. The peristaltic device (100) as claimed in claim 1, wherein the substance comprises one or more of a solid granular material, a fluid, a corrosive chemical, an abrasive, a slurry comprising one or more solids, a viscous fluid, and a gaseous substance. , Description:
BACKGROUND

[0001] Embodiments of the present specification relate generally to a peristaltic device, and more particularly, to a linear peristaltic device with a helical pump assembly.
[0002] A peristaltic device works on the principle of positive displacement of fluids. Typically, a peristaltic device consists of a series of rollers arranged in a circular fashion, or cams arranged in a linear manner that rotate to induce a peristaltic effect over a tube, thus causing a positive displacement. A peristaltic device, therefore, finds use in a positive displacement pump that is used to propel a variety of fluids. Positive displacement pumps make fluids move by trapping a specific volume of the fluid and displacing the trapped fluid into a discharge system. Such positive displacement pumps, also known as peristaltic pumps, can produce a constant flow at a particular speed irrespective of the discharge pressure.
[0003] Generally, peristaltic pumps can be categorized into two types, a rotary pump and a linear pump. A rotary peristaltic pump consists of a circular pump housing that contains a tube filled with fluid. In a typical rotary peristaltic pump, a resilient tube is disposed along a circular path with rollers mounted around the circumference of a circular rotor. These rollers move along the tube to occlude the tube and propel the liquid further into the tube. These pumps are relatively less efficient and constant usage causes tension and shear on the tube leading to erosion of the tube wall. The tube eventually flattens and carries less liquid.
[0004] Linear peristaltic pumps transport fluid through a tube using traveling contraction waves. A typical linear peristaltic pump consists of a series of sequential motor-driven cams that cause a peristaltic pumping action to transport fluid through the tube. Certain linear peristaltic pumps include devices, which compress the tube between a flat structure and a series of rollers that is mounted on a belt. These rollers are successively driven along the flat structure. Another variation of a linear peristaltic pump uses the circular roller motion in a linear pump assembly. In this variation, shaft mounted rollers interact with a tube that is fixed to a pivotal pump arm, which moves under the influence of the rollers. While linear peristaltic devices are efficient, they require a driving shaft and a number of cams along the driving shaft in order to cause pumping of the liquid. This makes them complex and cumbersome to handle.
[0005] For instance, patent application WO 2011071960 A2 discloses a helical peristaltic pump that consists of an inner shaft with several longitudinal channels about its the outer surface. Each channel has a flexible bladder with a magnetic outer surface and a cylindrical armature having a helical magnetic band. The armature spins around the inner shaft and causes the bladder to undulate. As the magnetic band approaches the bladder, magnetic attraction raises the flexible bladder and forms a cavity underneath the bladder. The cavity then travels in a peristaltic manner down the length of the shaft as the armature spins.
[0006] Such peristaltic pumps, however, are prone to shearing of the armature tube due to constant movement. The constant roller impact not only reduces the life span of the tubing, but also requires substantial actuating power. Moreover, an assembly of such devices include a number of cams, rollers and gears, which make them complex to manufacture and use. Therefore, it is desirable to develop a peristaltic device that will have fewer valves and rotating parts, that is simple to use and is durable, and provides a completely controllable pumping action of variable volume, speed, and pressure.

SUMMARY

[0007] According to one objective of the present disclosure, a peristaltic device is presented. The device includes a channel, and a flexible membrane disposed along an inner surface of the channel and adapted to hold a substance to be transported via the channel. The device further includes a helical member comprising one or more ridges and adapted to rotate about a selected axis of the channel. A distance between adjacent ridges of the helical member is selected such that the helical member constricts the flexible membrane at one or more points to lock the substance in one or more pockets within the flexible membrane, and displaces the locked substance in the linear direction along the channel upon rotation of the helical member.
[0008] According to one aspect, the device further includes a first gear operatively coupled to the helical member and a second gear disposed in an engaged position with the first gear. The device also includes a motor operatively coupled to the second gear and configured to rotate the second gear, wherein a rotation of the second gear rotates the first gear, which causes a corresponding rotation of the helical member about the selected axis of the channel.
[0009] According to an aspect, the channel comprises of an inlet port adapted to allow entry of the substance into the channel and an outlet port adapted to propel the substance out of the channel via the flexible membrane.
[0010] According to another aspect, the flexible membrane is fastened to the channel so as to form one or more columns that hold the substance without allowing the substance to move between the columns. The flexible membrane comprises one or more conduits having one or more cross-sectional areas to transport varying amounts of the substance through the channel.
[0011] According to another aspect, the helical member is a helical screw.
[0012] According to yet another aspect, the channel is composed of a rigid material, the flexible membrane is composed of an elastic material, and the helical member is composed of nylon, polyamide, steel, or any other material suited to be used with the flexible membrane (104). The rigid material comprises one or more of a metal, a polymer, a polypropylene and a polyvinyl material, the elastic material comprises one or more of an elastomer, a silicone, and a polyisoprene material.
[0013] According to an aspect, wherein the peristaltic device comprises one or more of a medical infusion pump, a heart-lung device, an acid dispenser, a biotechnology device, an ultrafiltration device, and an industrial pump.
[0014] According to another aspect, the substance comprises one or more of a solid granular material, a fluid, a corrosive chemical, an abrasive, a slurry comprising one or more solids, a viscous fluid, and a gaseous substance.
[0015] An objective of the present disclosure is to provide a peristaltic device design that allows transfer of the substance without allowing the substance to come in contact with other moving components of the peristaltic device, thereby preventing exposure of the peristaltic device to harmful chemicals and other corrosive substances or contaminating the substance itself. Another objective is to provide a cost effective and simple peristaltic device using the helical screw mechanism. Yet another objective of the present disclosure is to provide a durable peristaltic device durable comprising only a few moving components, thus resulting in lesser wear and tear. A further objective of the present disclosure is to provide a peristaltic device that may also be used to measure the substances to be transferred with accuracy and precision.
[0016] Additional features and advantages will be readily apparent from the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

[0017] These and other features, aspects, and advantages of the claimed subject matter will become better understood when the following detailed description is read with reference to the accompanying drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements in the drawings.
[0018] FIG. 1 illustrates a front perspective view of a peristaltic device, according to an embodiment of the present disclosure.
[0019] FIG. 2 illustrates a cross-sectional view of the peristaltic device depicted in FIG. 1, according to an embodiment of the present disclosure.
[0020] FIG. 3 depicts an exploded view of components of the peristaltic device depicted in FIG. 1, according to an embodiment of the present disclosure.
[0021] FIG. 4 depicts a front perspective view of a tube and a flexible membrane of the peristaltic device depicted in FIG. 1, according to an embodiment of the present disclosure.
[0022] FIG. 5 illustrates a magnified view of an unfolded flexible membrane with a substance trapped in the flexible membrane of the peristaltic device depicted in FIG. 1, according to an embodiment of the present disclosure.
[0023] FIG. 6 depicts a top view of the flexible membrane with the substance trapped in the flexible membrane depicted in FIG. 5, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0024] The following description presents illustrative embodiments directed to a linear peristaltic device with a helical screw mechanism. The peristaltic device comprises of a helical member that rotates when power is supplied to the helical member, disposed within a tube, by means of a motor. When the helical member rotates, a plurality of ridges of the helical member constricts a flexible membrane that is placed within the tube. When the flexible membrane is constricted, a substance trapped inside the flexible membrane forms a plurality of pockets that run along the length of the tube. The constant rotational movement of the helical member propels the pockets to travel forward, thereby pushing the substance out of the tube.
[0025] It may be noted that the pitch of the helical member may be selected depending on the viscosity of the substance, volume of the substance to be transferred, and other related parameters. The peristaltic device, as described herein, is simple to assemble and provides a cost effective substitute to the existing peristaltic devices and pumps. In an exemplary embodiment, the peristaltic device may be used to pump medicinal drugs or industrial substances such as corrosive chemicals and abrasives. Further, as no rotating tubes or belts are used in the construction of the peristaltic device, the peristaltic device experiences lesser shearing and is durable and long lasting. Also, the peristaltic device provides accurate measure of the substances to be transferred.
[0026] FIG. 1 illustrates a front perspective view of a peristaltic device (100). The peristaltic device (100) comprises of a tube (102) that forms the outer body of the peristaltic device (100). The tube (102), for example, may be composed of a rigid material such as a polypropylene, polyvinyl or any other suitable materials and compositions. In one embodiment, the inner wall of the tube (102) is layered with a flexible membrane (104) that is composed of an elastic material, for instance, elastomer, silicone, polyisoprene, or other suitable materials.
[0027] In an alternative embodiment, one or more flexible tubes or pipes may be mounted inside the tube (102) to serve as the flexible membrane (104). Particularly, in certain embodiments, multiple tubes of varying cross sectional areas may be mounted inside the tube (102) to deliver varying volumes of fluids through the same peristaltic device (100). Accordingly, the peristaltic device (100) may be used for dispensing medicinal drugs where varying dosages of the drug may need to be delivered based on a prevailing state of a patient.
[0028] According to aspects of the present disclosure, delivery of the fluid may be achieved by actuation of a helical member (106) disposed within the tube (102). The helical member (106), for example, may include a screw. A first gear (108) is mounted at one end of the tube (102), where the first gear (108) rotates, and in turn, actuates the helical member (106) to rotate around a selected axis, for example the central axis (120) of the tube (102). The peristaltic device (100) further includes a second gear (110) is engaged with the first gear (108) such that rotation of the second gear (110) causes a corresponding rotation of the first gear (108). In one embodiment, the peristaltic device (100) includes a motor (112) configured to supply power to the second gear (110) to enable the rotational movement of the second gear (110).
[0029] In an exemplary embodiment, a substance (114) enters the tube (102) via an inlet port (116). The substance (114) may be a solid substance such as a powder or grains, a liquid substance such as a medicinal fluid to be injected intravenously, a high solid slurry of a substance used in an industry, an abrasive, a viscous fluid, a gaseous substance, or other substances that may be transported via the peristaltic device (100). An outlet port (118) is situated at the opposite end of the tube (102) from the inlet port (116) to allow the substance (114) to be pumped out of the tube (102).
[0030] In one embodiment, the flexible membrane (104) is disposed as an inner lining along the inner circumference of the tube (102). Further, the flexible membrane (104) is fastened to the tube (102) along the length of the tube (102) at equally spaced distance, in such a manner that the flexible membrane (104) is divided into multiple columns that carry the substance (114) from the inlet port (116) to the outlet port (118). Further, the flexible membrane (104) is fastened to the tube (102) such that the substance (114) is not allowed to move from one column to the other column. According to aspects of the present disclosure, a pitch of the helical member (106) is selected such that a crest of the helical member (106) pinches the flexible membrane (102) locking the substance (114) in pockets within the different columns until the helical member (106) is rotated. Upon rotation of the helical member (106), the substance (114) moves through the tube (102) only in a linear direction. Certain exemplary components of the peristaltic device (100) and corresponding functions that allow for movement of the substance (114) from the inlet port (116) to the outlet port (118) of the tube (102) are described in greater detail with reference to FIG. 2.
[0031] FIG. 2 illustrates a front cross-sectional view (200) of the peristaltic device (100) of FIG. 1. Particularly, FIG. 1 depicts certain exemplary components of the peristaltic device (100). In one embodiment, the substance (114) enters the tube (102) via the inlet port (116). The substance (114) is trapped within the flexible membrane (104) upon entry into the tube (102). The motor (112) supplies power to the second gear (110), which results in rotation of the second gear (110). The rotational movement of the second gear (110) causes the first gear (108) that is disposed in an engaged position with the second gear (110) to rotate. The rotation of the first gear (108) causes the rotational movement of the helical member (106).
[0032] Further, in one embodiment, the helical member (106) consists of a plurality of ridges (202) that move along with the helical member (106).The distance between two adjacent ridges (202) of the helical member (106) is referred to herein as a pitch of the helical member (106). When the helical member (106) rotates along the central axis (120), the plurality of ridges (202) constricts the flexible membrane (104), trapping the substance (114), thus forming a plurality of pockets (204) along the length of the tube (102). With the rotation of the helical member (106), the substance (114) trapped in the plurality of pockets (204) is displaced along the length of the tube (114) in the direction of the helical member (106). Hence, the trapped substance (114) is propelled in the direction of the rotation of the helical member (106) and is pushed out of the tube (102) though the outlet port (118).
[0033] FIG. 3 depicts an exploded view (300) of certain exemplary components of the peristaltic device (100) depicted in FIGs. 1-2. As previously noted, the tube (102) forms the main outer body of the peristaltic device (100). In an exemplary embodiment, the tube (102) is substantially cylindrical in nature. However, in alternative embodiments, the tube (102) having one or more other shapes such as square, star, or pentagonal shape may be used provided the ridges of the helical member (106) constrict the flexible membrane (104) to generate one or more pockets that trap the substance (114). The tube (102) includes inlet port (116) and the outlet port (118) at opposite ends and the helical member (106), for instance, a helical screw composed of a nylon, polyamide or steel material. The helical member (106) includes the plurality of ridges (202) and the distance between the two adjacent ridges (204) may be selected based on the type and volume of substance to be pumped through the peristaltic device (100). The helical member (106) is disposed within the tube (102) about the central axis (120). In contrast to a complicated series of rollers or cams used in conventional peristaltic devices, use of the simple helical member (106) with a wider pitch that pinches and locks the substance (114) within the flexible membrane (104) allows for simpler and more cost-effective construction of the peristaltic device (100) due to fewer components. Additionally, as the pitch is constant between the ridges, the fluid trapped between the pitch remains constant and every single rotation of the helical member (106) releases the same volume of the substance (114) locked in between one pitch of the helical member (106). Thus, a volume or amount of substance (114) being transported can be controlled by controlling the rotations per minute of the motor (112).
[0034] Further, FIG. 4 illustrates a front perspective view (400) of the tube (102) and the flexible membrane (104) of the peristaltic device (100) where the helical member (114) is not shown in the view (400). In the present embodiment, the tube (102) of the peristaltic device (100) is depicted with the flexible membrane (104) disposed therein. The substance (114) to be transferred from one end to the other end of the tube (102) is trapped within the flexible membrane (104). The substance (114) enters the tube (102) through the inlet port (116) and is expelled from the tube (102) via the outlet port (118).
[0035] FIG. 5 illustrates a magnified view (500) of the unfolded flexible membrane (104) of the peristaltic device (100) depicted in FIGs. 1-4 with the substance (114) trapped in the flexible membrane (104). FIG. 5 depicts the magnified view (500) of the flexible membrane (104) when it is removed from the tube (102) and is unfolded. In the unfolded state, the flexible membrane (104) exhibits multiple columns (502) formed by fastening the flexible membrane (104) along the length of the tube (102), for example, at equally spaced distance. The flexible membrane (102) is fastened in a manner that the substance (104) is not allowed to move from one column to another. The columns restricts the substance (114) being transported from spiraling down in a direction that is opposite to the desired direction of movement, that is, the direction in which the substance is being pumped towards the outlet port (118). When the helical member (114) rotates and constricts the flexible membrane (104) at crest points of the plurality of ridges (202), the plurality of pockets (204) are formed. The plurality of pockets (204) includes the trapped substance (114) that moves in a linear direction through the length of the tube (102) upon rotation of the helical member (106).
[0036] FIG. 6 illustrates a top view (504) of the flexible membrane (104) with the substance (114) trapped therein. In the present embodiment, the multiple columns (502) formed by fastening of the flexible membrane (104) to the tube (102) at equally spaced distance are depicted when viewed from the top. The multiple columns (502) are formed along the circumference of the tube (102). The multiple columns (502) trap and transfer the substance (114) from one end of the tube (102) to the other end.
[0037] Embodiments described herein present an embodiment of the peristaltic device (100) for transferring a substance through the tube (102) using a simple helical screw mechanism. The peristaltic device (100) may be used as a medical infusion device. When used as a medical infusion device, the peristaltic device (100) may include single or multiple tubes with varied cross-sectional diameters to vary the drug dosage. Therefore, single peristaltic device (100) may be used to dispense various drug dosages.
[0038] In yet another embodiment, the peristaltic device (100) may be used to transfer industrial substances, for instance corrosive chemicals, abrasives, slurries of solids, highly viscous fluids, and other such substances. The peristaltic device (100) transfers the substance (114) without allowing the substance (114) to come in contact with other moving components of the peristaltic device (100), thereby preventing exposure of the peristaltic device (100) to harmful chemicals and other corrosive substances. Further, use of the helical screw mechanism enables the peristaltic device (100) to be cost effective and of simpler construction. As the number of moving components is few, wear and tear of the peristaltic device (100) is minimal, thus making the peristaltic device (100) durable and long lasting. Furthermore, as the size of the pitch remains constant, the peristaltic device (100) may also aid in measuring and dispensing the substances in every rotation with accuracy and precision. The present peristaltic device (100) also allows efficient control over the amount of the substance to be dispensed simply by means of selection of a suitable pitch size and rotations per minute.
[0039] Although specific features of various embodiments of the present systems and methods may be shown in and/or described with respect to some drawings and not in others, this is only for convenience. It is to be understood that the described features, structures, and/or characteristics may be combined and/or used interchangeably in any suitable manner in the various embodiments.
[0040] While only certain features of the present systems and methods have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the claimed invention.