PREVENTION OF JAMMING IN REGENERATIVE PUMPS DUE TO CORROSION

FIELD OF THE INVENTION

The present invention relates to regenerative self-priming pumps free of jamming due to galvanic corrosion or metallic bonding. More particularly, the present invention is directed to regenerative self priming and non self priming pumps adapted to operate with high efficiency and reliability free of any jamming between impeller and casing/volute disposed at close proximity and with very low clearance, resulting in enhancement of operating life span substantially. More importantly, the invention providing for a pump having aluminum alloy die cast casing/volute wherein the bracket or adapter with hydraulic passages comprising inserts made of engineering plastic of high wear resistance and chemical non reactivity to the fluid/water being handled and supports the casing and shaft favor eliminating corrosion or jamming related functional disorder even if the pump is kept idle for considerable time. The plastic inserts also provide means for easy maintainability by replacing the same instead of expensive and time consuming repair involving changing the entire casing/volute with adapter. Advantageously also, use of such plastic inserts in combination with aluminum alloy die cast static parts of pump particularly of volute, bracket or adapter is provided with precise tolerances in dimensions of radial and axial clearances between the impeller and the casing and bracket/adapter and also ensuring desired depth of channel on the lateral side of impeller, impeller width and impeller diameter etc, so as to favour high head vs discharge characteristics for longer operation life of the regenerative self priming/non self priming pumps for handling clean liquid/water. The present invention thus directed to substituting conventional cast iron static parts with combination of aluminum alloy die castings with plastic inserts favoring on one hand cost effectiveness, faster production and improved maintainability and on the other hand reduces the requirement of machining of cast parts, ensure desired functional and dimensional values with accuracy/precision, improved inherent wear resistance and good material stability for the plastic components and consequent improved reliability of performance and operating life. More advantageously, use of high strength aluminium alloy enables minimizing the wall thicknesses and thus reducing weight. Also the shape of component is suitably altered so that die casting is made with no external cores. Such hydraulic insert is functional part of the pump that carries the side channels of peripheral pump and is integrated with seal cavity and also holds mechanical seal used for sealing liquid. The regenerative self priming/non self priming pumps according to the present invention thus having prospects of wide industrial application for household water pumping application as well as for Industrial usage like air-conditioning refrigeration and heating applications primarily where steep Head-Discharge characteristics are required.

BACKGROUND ART
It is well known in the art of household water lifting pumps, regenerative pumps comprise an impeller and a volute having bracket or adapter mounted on casing with inbuilt hydraulic passage. As the impeller is rotated at desired RPM by a motor of appropriate rating coupled by means of shaft coupling to provide centrifugal motion to the liquid/water while the volute guides the flowing liquid from impeller to the delivery. During the non-operating period the difference in electro negativity with water as an electrolyte, the impeller and volute which are made of metals gets bonded by metallic bond through electron transfer, commonly called chemical corrosion. Due to this corrosion the rotating part (impeller) gets jammed with volute as the radial and axial clearance is usually of very small magnitude in the order of 0.12 to 0.18 mm on each side, thus creating lot of problems that affects hydraulic, thermal, chemical, mechanical properties/performance of such pumps. A substantial number of regenerative/centrifugal self Priming pumps are manufactured in India with power rating in the range of 0.11 to 1.1 Kw, comprising Cast Iron Parts which are prone to corrosion and erosion. Conventionally, attempts have been made to avoid the jamming in regenerative pumps by using different non-corrosive materials in pump parts like impeller, adapter and volute such as brass or stainless steel or even by using non-corrosive paints and electroplating to prevent corrosion. But these methods of prevention of corrosion on one hand involve complex processes and associated costs and on the other hand consume more time for production.

It is well known in the existing art that the self priming regenerative pumps also known as Turbine Pumps, Peripheral pumps, friction pumps, turbulence pumps consists of a radial bladed impeller of short length running in between a small chamber mounted on a counterpart called Bracket or Adaptor. The impeller comprises radial blades usually about 30 to 60 in numbers where the number of blades depends upon the diameter of Impeller. A typical impeller having two basic types of configurations known in the art -one having blades on both the sides and another having blades on only one side of the impeller/rotor disc. The chamber, in which the impeller rotates during pumping operation being driven by a motor of suitable power rating, is called a Casing having volute for exit passage. The casing conventionally has internal hydraulic passages with suction and delivery port attached or cast integral with it.

The impeller is housed rotatably in a chamber called a casing. The casing conventionally has internal hydraulic passages with suction and delivery port attached or cast integral to it. The chamber usually has a small valve attached to its suction port which helps in retention of fluid when the pump is stopped. The retained fluid acts as sealant in passages which helps in self-priming action of the pump. The casing is conventionally made up of cast iron or brass or steel depending upon specific application and cost implications. For non self priming peripheral regenerative pumps this non return valve is not mounted on the suction port of casing and also the casing does not have retention chamber.

The bracket or adapter has cast hydraulic passages and supports the casing and shaft. The impeller is mounted on the shaft and draws its power from the shaft. Like the casing, the bracket also plays an important role in hydraulic generation. The area and depth of channel cast or moulded on it plays important role in generation of head and discharge.

The head and discharge output of the pump depends upon the radial and axial clearances between the impeller and the casing & bracket. Besides this it also depends upon the depth of channel on the lateral side of impeller, impeller width and impeller diameter. The radial and axial clearances are very low and are to a tune of extent 0.12-0.18 mm per side. The higher the clearance the lower is the head and discharge.

Because of very low clearance these pumps can only handle clean clear water and cannot be used for liquids having suspended abrasive materials. These pumps when made out of cast iron casing and adapter become jam when kept idle for more than a week. The jamming is because of corrosion of surfaces of casing and adapter which are in close contact of impeller. The coat of iron film formed on the same due to galvanic corrosion wears of when impeller is running and due to this the clearances increases over time with the pump running. The increase in clearance results in drop of head and discharge of the pump and also reduces overall efficiency of the pump.

Regenerative Self Priming Pumps are used primarily for household water pumping application extensively. They can also be used for Industrial usage like air-conditioning and refrigeration or for heating applications. However, these pumps are particularly used with advantage where steep Head Discharge characteristics are required. Regenerative self priming pumps have many advantages like simple construction and energy efficient operation and more advantageously they can be used for liquids having low vapour pressure as they can handle both vapour and liquid without loss of prime.

It is thus experienced in the art that a technical solution was necessary to be attended to for handling clean water using regenerative self priming centrifugal pumps by ensuring on one hand desired dimensional accuracy and precision of clearances required to be maintained between the impeller and the casing and/or hydraulic passages or adapter/bracket and on the other hand favor elimination of corrosion and jamming of casing/adapter with impeller. When the pump is non-operating, the impeller and volute which are made of metals gets bonded by metallic bond through electron transfer commonly called corrosion due to the difference in electro negativity with water as an electrolyte. The rotating parts (impeller) of the centrifugal pumps get jammed with volute resulting in lot of problem that affects hydraulic, thermal, chemical, mechanical properties of the pump.

The present invention attempts to find a solution to this problem of corrosion and jamming in regenerative self priming water lifting pumps by using non corrosive materials for inserts selectively used in combination with preferred die cast non ferrous metal components for casing or adapter and hydraulic passages to meet the above requirements while maintaining desired head-discharge characteristics to favor a variety of applications.

US 5,435,464 is a patent entitled " System for the prevention of the jamming of pumps" states about a system wherein pumps used with containers having disposable liner contained therein, a pump and a housing attached to the lower end of the pump. The housing has at least one downwardly extending leg which serves to hold down the disposable liner thereby preventing the pump from being clogged or damaged by pieces of the flexible liner. The housing also has at least one passage there through to allow the flow of the medium being pumped upwardly through the central cavity of the housing. However, such a system is adapted for pumping grease un like the present invention that deals with pumping system for water or like fluid free of any suspended particles or any sludge and do not state about anticorrosive characteristics of parts.

US 6,612,821 is a prior patent that states about a pump, in particular gear pump including ceramic gears and seal, said pump having a housing with an inlet and an outlet. The gears are ceramic rotor gears which are journaled within the housing. A drive shaft drives the first gear in order to move it relative to the second gear, so as to pump a fluid from the inlet to the outlet of the housing said housing comprise an opening for the passage of the drive shaft and a seal surrounding the opening. The seal includes a first seal part rotating with the first gear, and a second seal part forming part of the housing. The first and second seal parts have facing sealing surfaces made of ceramic material and are loaded towards each other by a biasing member parallel to the drive shaft so as to obtain mechanical sealing between the gear and the housing obviating the need of sealing between the shaft and the housing.

US 4,465,445 is a prior art patent that disclosed 'A rotary pivoted vane pump' wherein a pivoted vane rotary pump especially for pumping food-stuff and abrasive material comprised a split housing in which a hub is rotatable, with an annular channel formed between the outer periphery of the hub and the inner periphery of the housing. Pivoted vanes on the hub are rotatable about radial axes. The housing is lined with elastomeric plastic material which is vulcanized to metal housing parts of pumps for handling foodstuff or corrosive media, or is vulcanized to metal carrier plates removably secured to housing parts of pumps for handling abrasive media. The pump can be easily disassembled for cleaning and for servicing, including replacement of the plastic lining of pumps for abrasive media. In one embodiment, a plastic axial guide member secured to the hub engages annular shoulders on pivot shafts of the vanes to prevent axial movement while permitting pivoting of the vanes.

Although the invention makes use of plastic/elastomeric materials for coating/lining of pump components but is for the purpose of enabling handling of abrasive media but not for handling of water pumps to avoid jamming as of the present invention due to galvanic corrosion or metallic bonding or wear of metal parts to maintain desired head-discharge characteristics.

US 6,293,773 is a patent that disclosed a corrosion-resistant sleeve for magnetic rotors of pumps, in particular for plastic-encapsulated magnetic rotors in centrifugal pumps, which effectively protects the rotors of laboratory centrifugal pumps from corrosion and premature wear. The invention do not however direct to providing any insert for hydraulic passage or adapter ensuring wear resistance and elimination of jamming due to corrosion of adjacent portion of impeller and casing/volute, as of the present invention.

US 4,810,918 states about a corrosion resistant ferrule secured to the end of a full carbon steel rotor shaft in order to reduce wear and corrosion of the sealing elements of the pump assembly, while enhancing the overall strength of the drive shaft. A threaded member is received in the end of the rotor shaft and ferrule in order to secure the pump impeller to the drive shaft. The corrosion resistant ferrule reduces manufacturing costs while allowing integral rotor shaft construction. The ferrule may be manufactured of stainless steel, plastic, or brass. This invention thus does not deal with wear resistance or galvanic corrosion resistance and metallic bonding of the static part like the casing/volute of the pump during idling nor it emphasize maintaining desired precise/accurate gap between the rotor and the casing to avoid wear/corrosion free of jamming for desired performance reliability in terms of head-discharge characteristics.

There has therefore been a persistent need in the art to developing a low cost alternative to conventional cast iron parts for volute or adapter for regenerative pumps adapted to faster production, low wear, longer operating life, ease of maintenance and ensuring desired steep Head-Discharge characteristics and high efficiency of such pumps while used as water lifting or like application, free of any jamming of rotor/impeller with the volute/casing due to galvanic corrosion or metallic bonding by selectively using inserts preferably made of engineering plastics in combination with aluminium alloy based metal die cast parts; favoring low cost, less weight and desired functional and dimensional requirements for ensuring reliable performance. The invention would also be capable of achieving mounting, production and usage methodology of Plastic inserts in regenerative self priming pumps and peripheral non self priming pumps in a simple, cost effective, reliable and efficient manner.

OBJECTS OF THE INVENTION

It is thus the basic object of the present invention to provide regenerative self priming pumps or a peripheral non self priming pumps adapted to avoid/eliminate corrosion and jamming of the impeller or volute/casing provided with substituting materials with inserts selectively disposed in the casing/adapter by way of hydraulic passage in a cost effective, reliable, durable manner ensuring faster production, longer operating life and desired head-discharge characteristics of the pump.

A further object of the present invention is thus directed to developing regenerative self priming pumps wherein the non rotating parts are selectively made of die casting with the bracket or adapter having releasable insert for hydraulic passage and support for mounting rotor/impeller shaft for superior wear resistance quality eliminating corrosion and jamming with reduced wear of parts and resulting longer operating life.

A further object of the present invention is thus directed to developing regenerative self priming pumps wherein the non rotating parts are obtained maintaining desired accuracy and precision of dimension of casing and preferred close spacing between impeller and volute for desired pump performance, requiring no or minimum machining of parts.

A still further object of the present invention to provide for plastic insert based parts of the bracket/adapter which would be cost effective wherein due to non metallic properties of the plastic insert and complete non reactivity to water, totally eliminates the chances of metallic bonding or galvanic corrosion and resultant jamming of adjacent portions of pump during idling for some days.

It is another object of the present invention to replace metal parts of bracket/adapter means in pumps subject to corrosion/deterioration with plastic parts and further the ease of replacement of such inserts as and when necessary without the need for replacing the whole metallic component to which it is attached and thus saving operating costs of spares/maintenance.

A still further object of the present invention is directed to developing regenerative self priming pumps wherein the plastic insert used is reinforced, heat stabilized and lubricated polyamide, favoring injection molding of such inserts for cost effective manufacture.

A still further object of the present invention is directed to developing regenerative self priming pumps wherein the plastic inserts are well suited for low wear and low friction applications.
A still further object of the present invention is directed to developing regenerative self priming pumps wherein the method of fixing the plastic insert with metal parts is simple yet secured to ensure reliable pump performance as well as ease of detachability.

A still further object of the present invention is directed to developing regenerative self priming pumps wherein said pump is used for liquids having low vapour pressure as they can handle both vapour and liquid without loss of prime.

A still further object of the present invention is directed to developing regenerative self priming pumps wherein by providing cast volute or other static part in combination with replaceable/removable plastic insert for shaft mounting or hydraulic passage provided on the casing or the bracket/adapter ensuring ease of production and manufacturing, reduced process time, low cost of parts/pump, consistent performance, low noise during operation due to low vibration and maintaining required clearance avoiding pump Jamming.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a bracket /adapter adapted for providing hydraulic passages and supporting the casing and shaft in pumps with impeller comprising:

a bracket base portion and a secured non-corrosive and wear resistant hydraulic insert comprising of a seal cavity and required hydraulic passage.

In the above bracket /adapter the hydraulic insert once assembled functions as an integral part of the adapter and can be separated out depending upon wear or tear of the hydraulic insert.

In accordance with a preferred aspect the bracket /adapter comprises aluminium bracket base portion and said hydraulic insert are manufactured from non-corrosive and wear resistant polymeric material preferably selected from Nylon 66, typical amides and any other engineering plastic having wear resistant property.

Importantly, in the bracket /adapter of the invention the seal cavity and the hydraulic passages are separately provided in said hydraulic Insert and are separately mounted on a Spigot.

Also, the adapter face is adapted for said replaceable securing of the hydraulic insert with respect thereto and preferably is strengthened by providing ribs.

According to a further aspect the shape and size of adapter face facing the replaceable insert is selectively provided including of triangular, rectangular or circular with Lugs / with out lugs depending upon the end application/purpose.

In accordance with further aspect of the invention, in the bracket /adapter of the invention a passage is provided between the bearing mounting face and hydraulic insert mounting face such that in case of leakage of seal the water does not enter in the bearing and subsequently in the motor body and preferably with two holes on face facing the insert wherein one hole accommodates a pin or a projection on the hydraulic insert cavity and another a screw which is screwed to hydraulic insert for replaceable securing of the insert with respect to the adapter body, a tapped holes adapted to hold the casing butted against the matching face of the adapter with a seal ring or a paper gasket or a plastic film involving anaerobic compound, projected lug means with tapped holes enabling the adapter to be mounted on the motor frame or bracket.

The channel of hydraulic passage is moulded and is separated with splitter means, the shapes of the splitter being selectively provided, the depth and width of channel being selectively provided.

The above disclosed bracket /adapter of the invention is advantageously adapted as bracket/adapter means for anyone of regenerative self priming, peripheral non self priming pumps as well as submersible pumps.

Advantageously also, both the components bracket base portion and a secured non-corrosive and wear resistant hydraulic insert are obtained of injection moulding/die casting machines.

In accordance with yet another aspect of the invention there is provided a pump assembly comprising of a bracket /adapter as discussed hereinbefore operatively connected to support a casing and shaft.

According to a preferred aspect the pump assembly comprises a small impeller whose diameter at periphery very from 35 mm to 150 mm and width vary from 4 mm to 25 mm depending upon the hydraulic performance required, the impeller vanes having thickness 'T 'varying from 0.5 mm to 2.5 mm depending upon process of machining and material properties with the length of vanes ranging from 4 mm to 20 mm and depends upon the diameter of impeller.

Also, the materials of impeller is selected from Cast Brass, bronze stainless steel or forged steel In accordance with yet further aspect of the invention, in the pump assembly the casing comprises a small chamber adapted to store liquid, said casing having a suction port and a delivery port and both these ports being split with a splitter ,said splitter in casing adapted to divide the suction port and delivery port and adapted to keep low clearance to a tune of 0.15 to 0.25 mm both in radial and axial direction of the impeller, the suction port being operatively connected to inlet by a channel ,a non return valve at the inlet of said channel to ensure the retention of fluid in the chamber, the delivery port being connected to delivery or outlet by a channel with or without additional rib adapted to aids in retention of fluid at the same time acts as a bifurcater to separate liquid and air, said casing having a channel separated by splitter means between suction and delivery port with the width and depth of channel depending upon Head and discharge characteristics of the pump, the said depth of channel further adapted to vary across periphery of impeller and more towards suction port and decrease towards delivery port.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1: is the schematic illustration of the impeller used in a conventional regenerative pump.

Figure 2: is the schematic illustration of the Casing used in a regenerative pump along with sectional view to highlight the hydraulic flow passages inside casing. Figure 3: is the schematic illustration of the CI adapter or bracket used in conventional self priming regenerative pump.

Figure 4: is the schematic illustration of the aluminium alloy die cast adapter/bracket according to the present invention reducing largely the requirement of finish machining.

Figure 5: is the schematic illustration of the hydraulic insert made of engineering plastic that is separately inserted forming part of the adapter/bracket according to the present invention.

Figure 6: is the schematic illustration of the assembled adapter/bracket with the hydraulic insert mounted on said adapter forming a detachable integral part of it according to the present invention.

Figure 7: is the schematic illustration of the shapes of alternative embodiments of splitters used in composite adapter with insert.

Figure 8: is the schematic illustration of the variations in channel depth and channel width to suit/depending on the head discharge characteristic of the regenerative pump to be achieved.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention is directed to developing a Self priming Regenerative Pumps comprising of a radial bladed impeller of short length running in between a small chamber mounted on a counterpart called Bracket or Adaptor, wherein said regenerative pump system incorporate plastic inserts in place of in combination with static metal parts as a cost effective measure directed to totally avoiding the chances of metallic bonding by way of non metallic properties of the plastic inserts in combination with non ferrous metal preferably high strength aluminium alloy die cast parts. The present invention is directed to replace static metal parts with plastic parts. Importantly also, the regenerative self priming or non self priming pumps adapted for both single sided or double sided vanes for the impeller, wherein the casing or adapter is configured to accommodate the plastic inserts/ hydraulic inserts to define flow passages for the fluid inside the pump casing/volute such that said inserts are used as reinforced, heat stabilized and lubricated polyamide making it suitable for injection molding. The plastic insert used in the pumps according to the invention is well suited for low wear and low friction applications, providing means for a suitable method of fixing the plastic insert with metal parts.

The manufacture of such regenerative pumps/components thereof are thus economic and productive so that the products are less costly yet reliable and long lasting and the operation and maintenance of such pumps used for handling clean water is operator/user friendly. The regenerative pumps using such hydraulic inserts for casing/adapter thus solves the problems relating to corrosion and jamming experienced in the prior art, particularly when the pump remains inoperative for some days/weeks, while ensuring the functional and dimensional requirements for desired high head-discharge characteristics of such pumps.

The objects and advantages of the regenerative centrifugal pumps according to the present invention described with greater details with reference to accompanying non limiting illustrative figures and embodiments as follows:

Reference is first invited to the accompanying Figure 1 that illustrates the impeller of a conventional regenerative pump. It is apparent that a small impeller whose diameter 'D' at periphery usually vary from 35 mm to 150 mm and width 'B' may vary from 4 mm to 25 mm depending upon the hydraulic performance required by end user. The impeller vanes can be cast machined or forged and have thickness 'T' may vary from 0.5 mm to 2.5 mm depending upon process of machining and material properties. The length of vanes T normally ranges from 4 mm to 20 mm and depends upon the diameter of impeller though there are no definitive formulas or relations established to this effect. The materials of impeller usually are Cast Brass / bronze stainless steel or forged steel. This Impeller is mounted on the shaft by either using a key and keyway 'K' for torque transmission to impeller or by using thread like typically using nut and bolts or providing female threads formed in the hub of Impeller and male threads on the shaft for the purpose of mounting the impeller on shaft. This impeller can also have a bore dimension of 'D' shape like type-2 as shown in the accompanying Figure 2.

Reference is next invited to the accompanying Figure 2 that illustrates the casing of the regenerative pump having a small chamber 'A' which is used to store liquid. The shape of and the size of chamber may vary depending upon aesthetic and quantity of liquid to be retained. This liquid helps in providing sealing film and also helps to act as a buffer to the sealing film so that this film is retained at all times under operation. The casing has a suction port and a delivery port and both these ports are split with a splitter shown as 'B'. The Splitter can be of various type of shape as shown in the accompanying Figure 7. The splitter in casing as already explained divides the suction port and delivery port and keeps low clearance to the tune of 0.15 to 0.25 mm both in radial and axial direction of the impeller. Thus at this splitter a small hydro dynamic film is formed which helps in forming a sealing film between these two ports. The suction port is connected to Inlet 'c' by a cast channel or can also be connected by a fabricated channel. The Inlet has provision to mount a flange or has threads which help in plumbing the pump to the suction or inlet pipe. At the inlet of this port a non return valve is usually fitted to ensure the retention of fluid in the chamber. The delivery port is connected to delivery or outlet 'D' by a cast channel. The channel may have an additional rib 'E' which aids in retention of fluid at the same time acts as a separator to separate liquid and air. The casing has a cast channel 'F'. The channel is separated by splitter 'B' between suction and delivery port. The channel has width 'G' and depth 'H'. The width and depth of channel varies depending upon Head and discharge characteristics of the pump. The depth of channel may also vary across periphery of impeller and may be more towards suction port and decrease towards delivery port. The channel may be cast or can be machined on the casings.

Reference is next invited to the accompanying Figure 3 that schematically shows a conventional adapter/bracket used in regenerative Pumps. This adapter is common configuration for both non Self Priming and self priming pumps. The adapter is conventionally made of Cast Iron or cast Steel. The face 'A' is normally butted with the face of the casing. The face of the casing and adapter are given the same shape and size and may be triangular shaped or square shaped or circular with or without projection of lug mounting. A typical near triangular shape according to an embodiment of the regenerative pump according to the present invention is shown in the accompanying Figure 3 and marked as 'S'.

The adapter or bracket has provision to fit a ball or sleeve bearing in case this is used on Monoset Pump where the motor and pump is having a common shaft and in case of coupled pumps where a pump and motor exist as separate units, this adapter is mounted on a separate bearing stand or can be integrated as separate part of the pump unit.

The adapter performs two functions- the first one is it has to convert kinetic energy imparted by the Impeller to the fluid into Hydraulic Energy and effectively seal the fluid from leaking to the surrounding. The Hydraulic Energy is imparted by the channel 'B' cast on the face of the channel. The channel takes in fluid from Suction port and delivers to delivery port by increasing the hydraulic energy of the fluid. The suction port and delivery port are separates by splitter 'C. The face 'D' comes and remains in close proximity of Impeller when complete pump is assembled. The clearance between this face 'D' and face of impeller is kept very low within a range of 0.1 to 0.2 mm.

The adapter has a second function of sealing by seal chamber 'E' integrally cast within it which houses a mechanical or a 'Lip seal' or a Dynamic rubber sealing ring.

Reference is next invited to the accompanying Figure 4 that schematically shows the adapter which constitute the subject of this invention. Unlike a conventional adapter this adapter is made of Aluminium alloy. The seal cavity and the hydraulic passages are separated from this adapter and are now called Hydraulic Insert (shown in Figure 5 later) and are separately mounted on the Spigot 'A'. The shape of the adapter is altered to make it adaptable for Aluminium alloy Die-casting to ensure close dimensional tolerances, and thus reducing the need for finish machining. Providing ribs 'C which are integrally cast on in Die Casting process strengthens the Adapter Face 'B'. The shape and size of Adapter face 'B' may change to triangular rectangular or circular with or with out lugs depending upon design. A passage 'D' is created between the bearing mounting face 'E' and hydraulic insert mounting face 'B' so that in case of leakage of seal the water does not enter in the bearing and subsequently in the motor body. Two holes marked as 'F' are provided on face 'B'. One hole accommodates a pin or a projection on the Hydraulic Insert cavity and another a screw which is screwed to Hydraulic Insert (as shown in Figure 5 later). The tapped holes 'G' hold the casing butted against the face 'B' with a seal ring like a 'O' ring or a paper gasket or a plastic film created by using Anaerobic Compound. The projected Lugs 'H' with tapped holes enable the adapter to be mounted on the motor frame or bracket. The shape, size and number of lugs can change depending upon the strength requirement and mounting geometry or method of construction like Monoset pumps (where motor and pumps share a common shaft) or a coupled pump where motor and pumps shaft are different and are coupled with a coupling.

Reference is now invited to the accompanying Figure 5 that schematically illustrates the details of a Hydraulic Insert which constitute part of the regenerative pumps according to the present invention. The Hydraulic passage namely channel 'B' is separated from the adapter as of the conventional configuration shown in Figure 3 along with seal cavity, and is separately mounted on the adapter as in Figure 4. The mounting is done on Face 'B' and is spigoted against Face 'B' of the adapter of Figure 4. The channel of hydraulic passage is moulded and is separated with Splitter 'A'. The shapes of the Splitter may vary and some typical variation in shapes is shown in accompanying Figure 7. The depth and width of channel may vary or may remain constant and its typical configurations are shown in accompanying Figure 8. The adapter here is now moulded with Plastic materials like Nylon 66 or typical Amides or any other Engineering Plastic which gives best Wear resistance Property and is inert to the fluid being handled by the regenerative pump.

Accompanying Figure 6 shows an embodiment of the assembly of adapter with hydraulic insert as of the present invention, both in isometric view and orthographic view and illustrates how this invented Hydraulic insert is mounted on the adapter with a dowel pin 'A' moulded pin on the Hydraulic Insert and how a screw 'B' is applied at the back of Insert to hold the two distinct parts -the metal and the plastic parts together. By adapting this procedure the Hydraulic Insert becomes an integral part of the adapter and can be separated out for replacement depending upon wear or tear of the Hydraulic Insert, instead of changing the entire component including the metal part in a simple, fast and cost effective manner facilitating maintenance, reducing down time and ensuring longer operating life with satisfactorily high operating efficiency.

It is thus possible by way of the present invention to developing a regenerative pump of self priming as well as non self priming type, adapted to avoid possibilities of jamming of the impeller and casing/adapter due to galvanic corrosion of metal parts or inter metallic bonding, during the non operating period by selectively providing plastic inserts in combination with aluminium die cast static parts like the casing or adapter/bracket, such that the functional and dimensional requirements in respect of precision and accuracy is are favourably maintained. Importantly, such regenerative pumps with hydraulic inserats to ensure flow passages within the casing ensure reliable performance with reliability and longer operating life while handling clean water ensuring desired head-discharge characteristic. Advantageously also, the inserts made of engineering plastic used in combination with static metal parts can be replaced with little effort and time when worn out without needing to replace the entire casing or adapter, thus making such pump systems economic, productive, simple to maintain and user friendly. The use of high strength aluminium alloy die cast components such as the casing or adapter further providing means for precise dimensional tolerances, reducing wall thicknesses of castings and thus reducing the weight of the same and the inherent wear resistive property of the engineering plastic used as hydraulic inserts integral to the adapter ensuring longer operating life without replacement. The hydraulic insert is configured to be separated from adapter/bracket for reshaping and integrating the same with the seal cavity. The self priming regenerative pumps with plastic hydraulic inserts as of present invention is thus capable of wide application and use for household and industrial purposes, used for pumping water or for other liquids having low vapour pressure and said pump capable of handling both vapour and liquid without loss of prime, such as for refrigeration and air-conditioning and heating applications.

WE CLAIM:

1. A bracket /adapter adapted for providing hydraulic passages and supporting the casing and shaft in pumps with impeller comprising:

a bracket base portion and a secured non-corrosive and wear resistant hydraulic insert comprising of a seal cavity and required hydraulic passage.

2. A bracket /adapter as claimed in claim 1 wherein the hydraulic insert once assembled functions as an integral part of the adapter and can be separated out depending upon wear or tear of the Hydraulic Insert.

3. A bracket /adapter as claimed in anyone of claims 1 or 2 comprising aluminium bracket base portion and said hydraulic insert comprises of non-corrosive and wear resistant polymeric material preferably selected from Nylon 66, typical amides and any other engineering plastic having wear resistant property.

4. A bracket /adapter as claimed in anyone of claims 1 to 3 wherein the seal cavity and the hydraulic passages are separately provided in said hydraulic Insert and are separately mounted on a Spigot,

5. A bracket /adapter as claimed in anyone of claims 1 to 4 wherein the adapter face is adapted for said replaceable securing of the hydraulic insert with respect thereto and preferably is strengthened by providing ribs.

6. A bracket /adapter as claimed in anyone of claims 1 to 5 wherein the shape and size of adapter face facing the replaceable insert is selectively provided including of triangular, rectangular or circular with Lugs / with out lugs depending upon the end application/purpose.

7. A bracket /adapter as claimed in anyone of claims 1 to 6 wherein a passage is provided between the bearing mounting face and hydraulic insert mounting face such that in case of leakage of seal the water does not enter in the bearing and subsequently in the motor body and preferably with two holes on face facing the insert wherein one hole accommodates a pin or a projection on the hydraulic insert cavity and another a screw which is screwed to hydraulic insert for replaceable securing of the insert with respect to the adapter body, a tapped holes adapted to hold the casing butted against the matching face of the adapter with a seal ring or a paper gasket or a plastic film involving anaerobic compound, projected Lugs means with tapped holes enabling the adapter to be mounted on the motor frame or bracket.

8. A bracket /adapter as claimed in anyone of claims 1 to 7 wherein the channel of hydraulic passage is moulded and is separated with Splitter means, the shapes of the splitter being selectively provided and the depth and width of channel being selectively provided.

9. A bracket /adapter as claimed in anyone of claims 1 to 8 adapted as bracket/adapter means for anyone of regenerative self priming, peripheral non self priming pumps as well as submersible pumps.

10. A bracket /adapter as claimed in anyone of claims 1 to 9 wherein both the components bracket base portion and a secured non-corrosive and wear resistant hydraulic insert are obtained of injection moulding/die casting machines.

11. A pump assembly comprising of a bracket /adapter as claimed in anyone of claims 1 to 10 operatively connected to support a casing and shaft.

12. A pump assembly as claimed in claim 11 comprising a small impeller whose diameter at periphery very from 35 mm to 150 mm and width vary from 4 mm to 25 mm depending upon the hydraulic performance required, the impeller vanes having thickness 'T 'varying from 0.5 mm to 2.5 mm depending upon process of machining and material properties with the length of vanes ranging from 4 mm to 20 mm and depends upon the diameter of impeller.

13. A pump assembly as claimed in anyone of claims 11 or 12 wherein the materials of impeller is selected from cast brass , bronze stainless steel or forged steel

14. A pump assembly as claimed in anyone of claims 11 to 13 wherein the casing comprises a small chamber adapted to store liquid, said casing having a suction port and a delivery port and both these ports being split with a splitter ,said splitter in casing adapted to divide the suction port and delivery port and adapted to keep low clearance to a tune of 0.15 to 0.25 mm both in radial and axial direction of the impeller, the suction port being operatively connected to inlet by a channel ,a non return valve at the inlet of said channel to ensure the retention of fluid in the chamber, the delivery port being connected to delivery or outlet by a channel with or without additional rib adapted to aids in retention of fluid at the same time acts as a bifurcater to separate liquid and air, said casing having a channel separated by splitter means between suction and delivery port with the width and depth of channel depending upon Head and discharge characteristics of the pump, the said depth of channel further adapted to vary across periphery of impeller and more towards suction port and decrease towards delivery port,

15. A bracket /adapter adapted for providing hydraulic passages and supporting the casing and shaft in pumps with impeller and a pump assembly involving the same.