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Shanghai Jianping Dynamic Balancing Machine Manufacturing Co., Ltd.

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Exhibition

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Pump Impellers need Balance

Claims:

1. An impeller for a rotary pump of the type having an impeller with flexible blades, said impeller being removably located in a pump housing having a removable end cover for access to said impeller, said impeller including a drive boss having a screw threaded aperture at one end thereof said impeller, in use, being removable from a pump drive shaft by rotation in said aperture of a screw threaded shaft compressively engageable with a free end of said drive shaft.                    

                 

2. An impeller as claimed in claim 1 wherein said screw threaded shaft includes a drive member for effecting rotation of said shaft.                    

                   

3. An impeller as claimed in claim 2 wherein said drive member comprises a shaped head at a free end of said shaft, said shaped head being engageable in use by a driving tool.                    

                   

4. An impeller as claimed in claim 3 wherein said drive member comprises a bolt head.                    

                   

5. An impeller as claimed in claim 1 including a plurality of flexible blades extending outwardly from the hub, said blades being removably secured in said hub.                    

                   

6. An impeller as claimed in claim 6 wherein the blades can be inserted in or removed from the hub by moving the blades in an axial direction relative to the hub.                    

                   

7. An impeller as claimed in claim 7 wherein the hub has a plurality of equally spaced profiled slots into which corresponding end portions of the blades can be inserted.                    

                   

8. An impeller as claimed in claim 8 wherein each blade is substantially symmetrical such that either of opposed end portions of the blade can be inserted into a respective profiled slot in said hub.                    

                   

9. An impeller as claimed in claim 5 wherein the blades and hub are made from different materials.                    

                   

10. An impeller as claimed in claim 1 wherein a seal is located against at least one end of the hub to establish, in use, substantially water tight zones between respective blades.                    

                   

11. An impeller as claimed in claim 11 wherein said seal is heat resistant.                    

                   

12. An impeller as claimed in claim 12 wherein the seal includes a central aperture.                    

                   

13. An impeller as claimed in claim 13 wherein the seal is an “O” ring.                    

                   

14. An impeller as claimed in claim 1 wherein a drive shaft is attached to the impeller by a lost motion device that allows at least limited relative rotation between the drive shaft and the impeller.                    

                   

15. An impeller as claimed in claim 15 wherein the lost motion device includes at least one impeller key mounted to the impeller and at least one drive shaft key mounted to the drive shaft such that upon rotation of the drive shaft the keys engage to rotate the impeller.                    

                   

16. An impeller as claimed in claim 17 wherein the lost motion device comprises a hollow tube mountable to the impeller, said hollow tube having equally spaced impeller keys formed on an inner circumference thereof and a collar mountable on the drive shaft and having equally spaced drive shaft keys formed on an outer circumference of the collar.                    

                   

17. A method of removal of an impeller from a rotary pump of the type having an impeller with flexible blades, said impeller being removably located in a pump housing having a removable end cover for access to said impeller, said method including the step of inserting, into a screw threaded aperture in one end of a drive boss of said impeller, a screw threaded shaft and rotating said shaft into engagement with a free end of an impeller drive shaft to urge said impeller outwardly of said pump housing.                    


Description:



BACKGROUND OF THE INVENTION

[0001] This invention relates to improvements to rotary pumps and more specifically to pumps that incorporate rotating flexible impellers for their pumping action.

[0002] Most rotary pumps have a housing that allows access to an impeller via an end cover. The impeller is driven by a drive shaft that causes water to be drawn through an inlet at low pressure and expelled through an outlet at higher pressure.

[0003] There are a number of refinements that can be added to this basic design that will assist monitoring of pump performance and condition whilst increasing pump reliability and simplifying the servicing or repair of the pump when required.

[0004] In certain applications, such as marine engine cooling pumps, it is difficult to identify if the pump is the cause of engine overheating without partial dismantling of the pump to visually inspect the flexible impeller for damage.

[0005] In numerous marine engine installations access to the pump is extremely difficult because of restricted access in the engine compartment and the physical location of the cooling pump on the engine.

[0006] In some cases it becomes necessary to remove adjacent parts of the engine such as alternators and drive belts, heat exchangers etc, to gain access to the cooling pump which can be quite hazardous in rough seas with an overheated engine.

[0007] Even without restricted access to a cooling pump, it is often difficult to remove an impeller for inspection and/or replacement due to frictional engagement between the impeller blades and the inner wall of the pump housing. This removal problem is exacerbated in large high capacity pumps where the impeller blades are relatively thick and apply a high restoring force against the pump housing.

[0008] Still further, if there is a degree of corrosion between the pump drive shaft and the drive boss of he impeller, a substantially greater axial force is required to remove an impeller.

[0009] Many attempts have been made over a period of time to shortcomings of “JABSCO” (TM) type liquid pumps or otherwise to provide improvements therein depending upon the end use application.

[0010] For example, British patent specification 870662 addresses the difficulty of impeller removal arising from frictional engagement between a drive shaft nd a drive boss by creating a thee point connection therebetween which permits about 3°- 5° of lost motion whilst being capable of transferring full drive torque.

[0011] Australian patent specification 244389 deals with impeller wear by providing replaceable impeller blades in a manner similar to that described in U.S. Pat. No. 2,976,811.

[0012] U.S. Pat. Nos. 3,592,572 and 2,678,003 respectively describe a pump for paste materials having a solid geared planetary rotor and a ball piston pump having a spherical rotor.

[0013] U.S. Pat. No. 3,054,355 describes a replaceable impeller having integral hinges formed in the impeller blades to assist flexure.

[0014] U.S. Pat. No. 4,538,962 describes mounting and removal of a cast metal centrifugal air blower wheel on a drive shaft by means of a tapered bushing or sleeve located between the shaft and the wheel hub.

[0015] U.S. Pat. No. 4,538,962 is concerned with the mounting and removal of a propellor on a drive shaft by a special nut adapted to secure propellor boss.

[0016] It is an object of this invention to overcome at least some of the above disadvantages or provide the consumer with a useful or commercial choice.

SUMMARY OF THE INVENTION

[0017] In one form the invention resides in an impeller for a rotary pump of the type having an impeller with flexible blades, said impeller being removably located in a pump housing having a removable end cover for access to said impeller, said impeller including a drive boss having a screw threaded aperture at one end thereof said impeller, in use, being removable from a pump drive shaft by rotation in said aperture of a screw threaded shaft compressively engageable with a free end of said drive shaft.

[0018] The pump may include a transparent safety cover and a transparent heat resistant insert spaced by a spacing means.

[0019] The transparent heat resistant insert may be made from any suitable material and may be of any suitable shape or size. Preferably, the transparent heat resistant insert is made from borosilicate glass.

[0020] The transparent safety cover may be made from any suitable material and may be of any suitable shape or size. Preferably the transparent safety cover is made from an acrylic plastics such as perspex or a polycarbonate plastics such as lexan.

[0021] The spacing means may be made of any suitable form. For example the spacing means may be a mounting ring. The spacing means may hold the transparent insert at a fixed distance from the transparent safety cover. Alternatively, the spacing means has a positioning means that allows the transparent heat resistant insert to position itself against the impeller. The positioning means may be a substantially flexible “O” ring. The “O” ring may be hollow.

[0022] The pump end cover may be attached to the housing by mounting means. The mounting means may include a mounting fastener that is able to extend through the pump end cover, and a retaining sleeve to prevent unwanted removal of the mounting screw from the pump end cover.

[0023] The mounting fastener may be a standard fastener such as an alien bolt or Phillips head screw.

[0024] The retaining sleeve may be formed from any suitable tubular flexible material. Preferably the retaining sleeve is made of natural or synthetic rubber.

[0025] The impeller may include a hub that is able to be attached to a drive shaft, and a plurality of flexible blades extending outwardly from the hub, wherein the blades are removable from the hub.

[0026] The blades may be inserted or removed from the hub by moving the blades in an axial direction relative to the hub.

[0027] The hub may have a plurality of equally spaced profiled slots into which corresponding end portions of the blades can be inserted.

[0028] Each blade may be substantially symmetrical such that either end portions of the blade can be inserted into a profiled slot.

[0029] The blades and hub may be made from different materials having different wear properties so that both the hub and the blades operate more effectively.

[0030] A seal may be located on at least one end of the hub to establish substantially water tight zones between respective blades. Preferably, the seal is an “O” ring.

[0031] The impeller may also include a threaded hole that is in communication with a drive boss such that a threaded shank can be rotated within the threaded hole to remove the drive boss from the drive shaft.

[0032] The shank may be of any suitable form. Preferably, the threaded shank forms part of a bolt. Hence a required amount of torque can be applied to the bolt through the use of a spanner or the like.

[0033] The drive shaft may be attached to the impeller by a lost motion device that allows at least limited relative rotation between the drive shaft and the impeller.

[0034] The lost motion device may be of any suitable form. Typically, the lost motion device includes at least one impeller key mounted to the impeller and at least one drive shaft key mounted to the drive shaft such that upon rotation of the drive shaft the keys contact each other to rotate the impeller.

[0035] Preferably the lost motion device comprises a hollow ring mountable to the impeller having three equally spaced impeller keys formed on an inner circumference of the ring, and a collar mountable to the drive shaft having three equally spaced drive shaft keys formed on an outer circumference of the collar.

[0036] A pressure sensing nipple may used to determine the pressure within the pump and also fasten a cam of the pump. After much trial and experimentation it has been found that placement of the nipple through the cam will give a value of pressure proportional to the outlet pressure of the pump.

[0037] A temperature warning device may be attached to the transparent heat resistant insert to monitor the temperature of the pump.

[0038] The temperature warning device may be attached adjacent the centre of the transparent heat resistant insert as heat generated by friction of the impeller rubbing against the pump will at be at its most intense at the centre of the transparent insert.

[0039] In another form, the invention may include a pump end cover including:

[0040] a transparent safety cover able to be attached to a pump housing;

[0041] a transparent heat resistant insert able to contact the impeller; and

[0042] a spacing means to space the transparent heat resistant insert from the transparent safety cover.

[0043] The pump end cover may have the same features as described previously.

[0044] In another form the invention may include an the impeller including:

[0045] a hub able to be attached to a drive shaft and a plurality of flexible blades extending outwardly from the hub;

[0046] wherein the blades are removable from the hub.

[0047] The impeller may have the same features as described previously.

[0048] In another form the invention may include a removable blade for a flexible impeller including an end portion that is able to be inserted within a profiled slot of a hub of the impeller.

[0049] The blade may have the same features as described previously.

[0050] In another form, the invention may include an impeller including a threaded aperture that is in communication with a drive boss of an impeller such that a threaded shank can be rotated within the threaded hole to move the shank inwardly to remove an impeller drive boss from a drive shaft.

[0051] The impeller may have the same features as described previously.

[0052] In another form, the invention may include a lost motion device for connecting a drive shaft to an impeller, the lost motion device allowing reverse rotation of the drive shaft of less than 360 degrees without rotation of the impeller.

[0053] The lost motion device may have the same features as described previously.

[0054] In another form the invention may include a pressure sensing nipple that is used to determine the pressure within the pump and also to fasten a cam of the pump.

[0055] The pressure sensing nipple may have the same features as described previously.

[0056] In another form the invention may include a temperature warning device for a pump, the temperature warning device attached to an end cover to monitor the temperature of the pump.

[0057] The end cover may be constructed from any suitable materials such as metal. Preferably the end cover is constructed similar to that described previously.

[0058] The temperature warning device may be attached adjacent the centre of the end cover.

[0059] The temperature warning device may be attached to the transparent heat resistant insert.

FIG. 1FIG. 1