Claims:I Claim,

1. An agitator drive assembly for driving an agitator (mixing member) (4) for agitating fluid within a reactor vessel (8) comprising a drive unit (2) being secured and supported by a tripodal lantern housing (3) on the reactor (8);

wherein said lantern housing (3) comprises at least three posts (3d) vertically mounted on the top of the reactor (8) to form an elongated conical and tripodal housing (3) and being supported on a supporting plate (3e), a gear box mounting base plate (3a) being mounted on the top of said housing (3), a bearing housing base plate (3b) being located at the intermediate portion of the said housing (3) and a cylindrical drive stool base plate (3c) being located at the bottom of said housing (3) and having an opening that receives in nozzle of the reactor; said drive stool base plate (3c) is bolted with the supporting plate (3e) through a bolt assembly (3f);

wherein said drive unit (2) comprises an electric motor (9), a gear box (10) operatively connected with the motor (9) and being releasably located on the gear box mounting base plate (3a) through a bolt assembly (10a), a drive shaft (11) being operatively extended downward from said gear box (10), a agitator shaft (12) having an inboard end being axially extended into the reactor (8) through a nozzle (8a), said mixing member (4) is operatively connected to the inboard end of the agitator shaft (12) for agitating fluid within the reactor (8) in response to rotation of the agitator shaft (12), a bearing housing (6) includes plurality of self aligned ball bearings for reducing deflection and vibration of the agitator shaft (12) during operation, said bearing housing (6) is releasably supported by the bearing housing base plate (3b), a split muff (clamp) coupling (7) for selectively and releasably interconnecting the agitator shaft (12) in driven relationship with the drive shaft (11), a dynamic mechanical seal assembly (5) that is supported by an adaptor plate (13) being releasably fitted on the drive stool base plate (3c) through fastening bolts (5a), said mechanical seal assembly (5) axially fixed relative to the agitator shaft (12) to prevent the fluid contained in the reactor (8) from leaking along the agitator shaft (12) and bearings and a thermosiphon cooling means (14) being secured with one of the post (3d) through a spigot (16) for circulating cooling oil to the mechanical seal assembly (5);

wherein said split coupling (7) is configured to have an access for enabling inspection of bearings in bearing housing (6) and the mechanical seal (5) without replacing gear (10) and agitators (4) and a hanger bolt (12a) that holds the agitator shaft (12) in place while dismantling the agitator drive assembly for enabling the maintenance of bearings secured in the bearing housing (6) and the mechanical seal assembly (5);

wherein said mechanical seal assembly (5) and the bearing housing (6) are removed and replaced by sliding it upwardly along the agitator shaft (12).

2. The agitator drive assembly as claimed in claim 1, wherein said adaptor plate (13) is a glass lined steel.

3. The agitator drive assembly as claimed in claim 1, wherein the agitator shaft (12) is axially hanged from its top by a dummy bolt (17) for removal of the mechanical seal assembly (5) and the bearing housing (6).

4. The agitator drive assembly as claimed in claim 3, wherein said dummy bolt (17) is suspended by the crane or other hanging means.

5. The agitator drive assembly as claimed in claim 1, wherein said mixing member (4) includes simple impellers, marine propeller, straight blade turbine, narrow blade turbine, pitch blade turbine, narrow blade impeller, wide blade impeller, axial flow turbine, concave blade disc turbine, toothed disc, turbo propeller, flat blade turbine, backward turned turbine, paddle, anchor, anchor/paddle.

Dated this on January 13, 2016.
, Description:FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

1. TITLE OF THE INVENTION: AGITATOR DRIVE ASSEMBLY
2. APPLICANT:
(a) NAME : Amin Sudarshan Purshottamdas
(b) NATIONALITY : Indian
(c) ADDRESS : S.No. 881, 882/1+2, 882/3+1, 882/3+2, 883, 885,
Near New Water Reactor of G.I.D.C. Phase-IV
At. Karamsad, Ta. & Di. Anand -388325

3. PREAMBLE TO THE DESCRIPTION
þ COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

Field of Invention:

The present invention relates to an agitator for use in stirring, agitating, mixing, and so forth materials such as reactants and reaction products within a large vats or reactors and more particularly it relates to an agitator drive assembly that provides inline configuration for ease of assembling and disassembling of components that drive an agitator (mixing member) and for being applicable to the glass lined reactors and other vessels.

Background of Invention:

The agitator mixers are generally used for mixing solid & liquid materials with fluids in the pharma/chemical/food-processing industry. These devices are constructed with the object of achieving the greatest possible mixing efficiency with the lowest possible power consumption.

At present, the demand for reactors with agitators is estimated at 40,000 per annum and the industry is growing at higher needs of the agitators. At present, most of these reactors are manufactured using helical agitator gear boxes by replacing worm reduction gear boxes. A few reactor manufacturers use planetary agitator instead of helical gear due to larger reduction ratio requirements and compact size. However, all the conventional agitators used for manufacturing reactors have different design specifications which impact the drive system performance. Also, the dimensions of same rating gear boxes differ in mounting dimensions from manufacturer to manufacturer causing difficulties to Original Equipment Manufacturer (OEM) for switching over from one make of gear box to another make of gear box.

Conventional agitators have also come across with the common problem of oil leakage and have common difficulties to get the required run-out and squareness at the seal area. It is also important to note that it’s difficult for conventional devices to get the same run-out and squareness at seal area once opened for maintenance.

One of such agitating apparatus has been disclosed in U.S. patent no. 3796108 that discloses the apparatus for driving agitators. Said system discloses a right angle speed reducer incorporates speed change gears for varying the output shaft speed, spiral bevel gearing, all tapered roller bearings, splash lubrication of all high speed bearings, and a dry well output for the lower output shaft bearing.

However, such conventional agitators are assembled on fabricated unmachined housing and the alignment of shaft in such kind of agitators is achieved by using dowels and seam packing. This kind of assembly may disturb the alignment due to vibrations.

Further, due to complexity in structure of conventional agitators, for maintenance or replacement of any component thereof, other parts needs to be tempered that leads to time consuming task for assembling and disassembling the components. For example, to inspect and repair the mechanical seal necessitates the upward withdrawal and/ or removal of the upper drive portion of the agitator from the lower driven portion of the shaft.

Hence, it is desperately needed to invent an agitator drive assembly that overcomes the shortcomings of conventional agitators.

Object of Invention:

The main object of present invention is to provide an agitator drive assembly for agitating and mixing liquid in the reactor is to have inline configuration to realize low cost, light weight, compact configuration and rugged construction.

Another object of present invention is to provide an agitator drive assembly that eliminates the use of fabricated unmachined housing for holding components and also eliminates the use of dowel or any other seam packing for achieving the alignment of shaft.
Further object of present invention is to provide an agitator drive assembly that provides greatest ease of maintenance or replacement of the shaft seal and bearings without the necessity of emptying the mixing reactor.
Yet another object of present invention is to provide an agitator drive assembly that is configured to perform ease of assembling and disassembling the components that operates the agitator.

Yet another object of present invention is to provide an agitator drive assembly that is configured to reduce the operating temperature at the mechanical seal faces, extending the life of the seal.

Summary of Invention:

The present invention relates to an agitator drive assembly that comprises a drive unit for operating the agitator (mixing member) to agitate the liquid within the reactor. Said drive unit is supported and secured by a tripodal lantern housing being mounted on and projected upwardly from the outer body of said reactor. Said drive unit comprises a motor driven gear reduction box, a split coupling, a drive shaft, an agitator shaft, a bearing housing and a mechanical seal assembly. Said lantern housing comprises a gear box mounting base plate on its top side for holding a motor driven reduction gear box, a bearing housing base plate for supporting a bearing housing and a drive stool base plate at its bottom having an opening for receiving the agitator shaft. The dynamic mechanical seal assembly is releasably disposed through the glass lined adaptor plate bolted with the drive stool base plate. A drive shaft is extended from reduction gear box and is detachably connected with the agitator shaft through the split coupling having hanger bolt for holding the agitator shaft and having an access to enable inspection of bearings and seal without replacing gear and agitators. Said agitator shaft has an inboard end at which the mixing member is connected for agitating and mixing liquid in the reactor. The entire agitator drive assembly according to present invention is built in a way that all parts are easily assembled and disassembled without dismantling the agitator shaft and mixing member from the reactor.

Brief Description of Drawings:

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.

Figure 1 shows a perspective view of agitator drive assembly according to present invention.

Figure 2 shows a cross sectional view of lantern housing having straightly elongated posts according to present invention.

Figure 3 shows a plan view of lantern housing shown in Fig. 2.

Fig. 3a shows a cross sectional view of post being employed in the housing lantern shown in Fig. 3.
Figure 4 shows another embodiment of lantern housing according to present invention.

Fig. 4a show a cross sectional view of a post being employed in the lantern housing shown in Fig. 4.

Figure 5 shows a cross sectional view of agitator drive assembly according to present invention operatively associated with a chemical reactor vessel.

Figure 6 shows a cross sectional view of agitator drive assembly after removal of gear box and drive shaft according to present invention.

Figure 7 shows a sequence of removal of a bearing housing and a mechanical seal from the agitator drive assembly according to present invention.

Detailed Description of Invention:

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompany drawings. The invention is capable of other embodiment, as depicted in different figures as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

It is to be noted that in given exemplary embodiment, an agitator drive assembly is mounted vertically at the top of the reactor. This is the normal practice for mounting an agitator in small and medium size reactors. However, it is also configured to mount horizontally from side of a reactor, called side entering agitator, for very large diameter storage reactors.

The agitator drive assembly (1) shown in Fig. 1 to Fig. 7 according to present invention is particularly adapted to mix contents of a glass lined chemical reactor (8) contained with material to be mixed and stirred having a closed top provided with a nozzle (8a) terminating in a circular flange for the reception of a vertical agitator shaft (12) extending through the nozzle (8a) downwardly into the reactor (8) and provided therein with one or more impellers or agitators (4) for mixing the reactor contents, as well understood in the art. Aggressive material to be stirred is introduced into the reactor (8) having its inside walls coated or made with material which is resistant to the aggressive corrosive characteristics of the material.

Fig. 1 to Fig. 7 depicts an agitator drive assembly (1) for driving an agitator according to present invention in its normal operating condition. The agitator drive assembly (1) mainly comprises a drive unit (2) that is secured and supported by a tripodal lantern housing (3) on the reactor (8) for driving the agitator (mixing member) (4) as shown in Fig. 5.

Fig. 2 and Fig. 3 show a first embodiment of the configuration and construction of the tripodal lantern housing (3). As shown in Fig. 2 and Fig. 3, said lantern housing (3) comprises three straight posts (3d) (shown in Fig. 3a) being radially extended at the angle with respect to the top surface of the reactor (8), only some of which are shown in Fig. 2, to form a conical and tripodal lantern housing (3) that is projected upwardly from the top wall of the reactor (8). Said posts (3d) are supported on the supporting plate (3e) (shown in Fig. 5). Said lantern housing (3) preferably made from material like graded cast iron, carbon steel plate and stainless steel plate for providing optimal impact strength thereto. It further comprises a circular gear box mounting base plate (3a) on its top portion. At intermediate space of the housing (3), a bearing housing base plate (3b) is mounted. At the bottom of the housing (3), a circular drive stool base plate (3c) is mounted which is welded to the outer top of the reactor (8) and bolted with the plate (3e) through a bolt assembly (3f) (shown in Fig. 5). Said gear box mounting base plate (3a), the bearing housing base plate (3b) and the drive stool base plate (3c) are concentric and the diameter is gradually increased from the gear box mounting base plate (3a) to the drive stool base plate (3c). The base plate (3c) is substantially of ring-shaped, and provided with an opening (not shown) in the center thereof having a size substantially similar to the nozzle (8a) of the reactor (8) for receiving the agitator shaft (12).
In another embodiment of the construction of said tripodal lantern housing (3) that provides better structural rigidity, each post (3d) is a one piece component with no joints comprises a first portion and a second portion (3d’) curved at an angle a relative to one another to form an apex (3d”) as shown in Fig. 4a. The lower ends of each said post (3d) are anchored on the plate (3e). In this embodiment, the posts (3d) are extended vertically to form a conical and tripodal lantern housing (3) wherein the gear box mounting base plate (3a) is supported on the apex (3d”) of each post (3d) as shown in Fig. 4. While this embodiment utilizes an angle a of approximately 120 degrees, angle ranging between approximately 90 to 120 degrees may also be used. Other configuration of said housing (3) according to present embodiment remains same as discussed in the first embodiment.

Fig. 5 illustrates the agitator drive assembly (1) according to present invention being mounted on the reactor (8) in its operating condition. According to Fig. 5, the drive unit (2) comprises an electric drive motor (9), a reduction gear box (10) bolted on the gear box mounting base frame (3a) through a bolt assembly (10a) and operatively connected inline with the motor (9), a drive shaft (11) being downwardly extended from the gear box (10), an agitator shaft (12) having an inboard end located within the reactor (8), said mixing member (4) is operatively connected to the inboard end of said agitator shaft (12) for agitating the fluid within the reactor (8) in response to the rotation of the agitator shaft (12), a bearing housing (6) being mounted on the bearing housing base plate (3b) and a split muff (clamp) coupling (7). However, it has to be understood that in said embodiment of present invention, preferably a split muff or clamp coupling (7) is used but it may be any prior art coupling including, but not limited to, a sleeve coupling and a flange coupling. Further, it should also be noted that said mixing member (4) includes simple impellers, marine propeller, straight blade turbine, narrow blade turbine, pitch blade turbine, narrow blade impeller, wide blade impeller, axial flow turbine, concave blade disc turbine, toothed disc, turbo propeller, flat blade turbine, backward turned turbine, paddle, anchor, anchor/paddle.

Said bearing housing (6) consists of plurality of self aligned rollers or ball bearings (not shown) which are secured inside the bearing housing (6). Said bearings arrangement rotatably supports the agitator shaft (12) for reducing deflection and vibration of the shaft (12) during operation. Said bearing housing (6) is suitable for wide range of bearing for different shaft diameter also consists of a bearing size adjustment sleeve (not shown) and a sleeve locking screw (not shown) to ensure the required diameter for different size of bearing. The bearing housing (6) secures grease lubricant for bearing to remain in the bearing housing (6) and to avoid any outside particle enters in the bearing housing (6).

There are two basic types of reduction gears available for the present application. The first type, illustrated in the Figures, has a drive shaft extending from the gearbox such that a flange of split muff coupling may be used. The second type has just a shaft sleeve extending from the gearbox, whereby the coupling of the propeller drive shaft takes place by just pushing the propeller shaft into the shaft sleeve and locking it therein for preventing axial movement of the propeller drive shaft.

The drive shaft (11) is rotatably operated by said motor (9) and the reduction gear box (10). The gear box (10) consists of a multiple gear reduction stage (not shown) in connection with said drive shaft (11) for adjustment of the required rpm and torque of a rotatable drive shaft (11). The drive shaft (11) extended from the reduction gear box (10) is detachably and operatively connected with the agitator shaft (12) through said split muff coupling (7) for precise alignment of said shafts. Here, the lower end portion of drive shaft (11) and upper end portion of agitator shaft (12) are connected by two half cylinders that are held together by fastening bolts (7a). Further, said coupling (7) comprises an access (not shown) for enabling inspection of bearings in bearing housing (6) and the mechanical seal (5) without replacing gear and agitators and a hanger bolt (12a) that holds the agitator shaft (12) in its place while assembling and disassembling the drive shaft (11) and other components of drive assembly (1) for maintenance of the bearing housing (6) and the mechanical seal (5). This mechanism of split muff coupling (7) radially and axially secures the drive shaft (11) and the agitator shaft (12). It is to be noted that other kinds of rigid coupling like flange coupling or a sleeve coupling are employed for aligning the drive shaft and agitator shaft. It will be seen that when gear reduction box (10) is driven by said motor (9), the drive shaft (11) is drive, which through coupling (7), drives the agitator shaft (12).

Said agitator shaft (12) is extended into the reactor (8) through a mechanical seal assembly (5) that is arranged for preventing leakage of the fluid contained in the mixing reactor (8) during agitation. An annular adaptor plate (13) is supported on the drive stool base plate (3c) that is made from glass lined steel. A plurality of fastening bolts (5a) pull the adaptor plate (13) down towards the nozzle (8a), compressing the drive stool base plate (3c). A mechanical seal assembly (5) is supported and secured on said adaptor plate (13) in accordance with this invention for maintenance of any desired pressure within the reactor (8). The drive stool base plate (3c) has an opening for the agitator shaft (12) where the mechanical seal assembly (5) surrounds the shaft (12). The mechanical seal assembly (5) has a rotatable part locked on the agitator shaft (12) by means of, for instance, screws and a stationary part fastened with said base plate (3c) to form a dynamic seal. The mechanical seal assembly (5) provided by the present invention is a package rotary seal cartridge assembly which is removable as a unit by sliding it along the shaft (12) in the manner as discussed below. This arrangement also ensures that the fluid to be mixed will not be contaminated by lubricants such as grease and/or oils leaking from the bearings.

Further, Said lantern housing (3) provides bracket (15) on any of its post (3d) for holding a thermosiphon cooling system (14) through a spigot (16). During the operation of said mechanical seal (5), the rotatable part and stationary parts remains in contact with each other for tight seal. The frictional contact between these parts generates heat. Hence, it is desirable to transfer the heat away from the seal faces. Said thermosiphon cooling system (14) circulates continuous flow of oil in the mechanical seal assembly (5) thereby cooling is provided to the mechanical seal assembly (5). Said thermosiphon cooling system (14) directly affects the performance of a mechanical seal and extends its mean time between failures (MTBF).

Dismantling and reassembly of the apparatus itself is carried out as follows: The agitator is stopped and the gear box (10) is separated by releasing the bolt assembly (10a) from the gear box mounting base plate (3a). After that, said split coupling (7) allows the separation of the drive shaft (11) and the agitator shaft (12) that enables ease of maintenance of bearings being secured in bearing housing (6) and said mechanical seal assembly (5) without extracting the agitator shaft (12) from the reactor (8).

Further, as shown in Fig. 6 and Fig. 7, the agitator drive assembly (1) comprises a dummy bolt (17) detachably connected to the top of the agitator shaft (12) after removal of the gear box (10), the drive shaft (11) and the hanger bolt (12a). Said dummy bolt (17) is vertically suspended by a hook means (18) for axial suspension of agitator shaft (12) as shown in Fig. 6. Said arrangement allows the removal and replacement of the bearing housing (6) and the mechanical seal (5) along with the adaptor plate (13) successively by pulling upwardly sliding along the length of said shaft (12). Subsequently, the agitator shaft (12) is fixed by the clamping means (19) that holds the agitator shaft (12) in axial position after disconnecting the dummy bolt (17) from the agitator shaft (12). It is to be noted that the hook means (18) is operated by crane or other suitable hanging means. Hence, from the foregoing description, it will be noted that the entire agitator seal assembly is readily removable and replaceable as a unit.

The invention has been explained in relation to specific embodiment. It is inferred that the foregoing description is only illustrative of the present invention and it is not intended that the invention be limited or restrictive thereto. Many other specific embodiments of the present invention will be apparent to one skilled in the art from the foregoing disclosure. All substitution, alterations and modification of the present invention which come within the scope of the following claims are to which the present invention is readily susceptible without departing from the spirit of the invention. The scope of the invention should therefore be determined not with reference to the above description but should be determined with reference to appended claims along with full scope of equivalents to which such claims are entitled.