APPARATUS FOR UNCOUPLING THE THREADED CONNECTION OF A PUMP IMPELLER

Abstract: An apparatus for uncoupling a threaded joint between a pump or turbine shaft and an impeller (42), using the power of a hydraulic cylinder (16) is disclosed. The apparatus has a housing (10) with a V-shaped upper surface (12) for supporting the end of the pump (40) adjacent the impeller (42), a vertical support (2) for supporting the opposite end of the pump (40) which is adjustable in height and distance from the housing (10), and a hydraulic cylinder (16) which is pivotally mounted (18) on the side of the housing (10) remote from the support (2). The rod (26) of the hydraulic cylinder (16) has attached to it a chain (28) and hook for attachement to the impeller blade (42).

Description: The invention relates to the general field of power apparatus for uncoupling threaded joints in articles of heavy equipment. More particularly, the invention relates to a hydraulically-powered apparatus for uncoupling the threaded connection of large pump impellers. Certain items of rotating heavy equipment have threaded connections which tend to tighten as the equipment is operated. For example, the threaded joints in earth drilling equipment become tight during operation and consequently are difficult to disassemble. Similarly, the impellers in large turbine pumps are connected to the lower end of the drive shaft by a threaded coupling which tightens as the pump is operated. Consequently it is difficult to remove the impeller in order to replace it or repair it. Various power-operated apparatus have been developed to assist in breaking or uncoupling the threaded connections in such heavy equipment. Typically such apparatus are complicated and expensive to operate. For example, US-A- 3,256,757 inventor Kochaver discloses a power wrench for breaking the threaded joints in earth drilling equipment. This device utilizes two pipe wrenches, one anchored to the frame and a second one powered by a hydraulic cylinder. Activation of the cylinder causes one of the wrenches to rotate a portion of the drill pipe in correlation to the anchored portion. Similarly, US-A- 4,092,881 issued June 6, 1978, inventor Jurgens et al., discloses a power apparatus for breaking the threaded connections between drill strings. This device utilizes a stationary chuck and a rotable chuck, with the structure of the chucks being quite involved. The particular structure for the rotatable chuck is specifically designed for tubular bodies. US-A- 4,295,257 issued October 20, 1981 to Strohs discloses a work stand for supporting and aligning the various components of a vertical turbine pump during assembly or disassembly. The apparatus provides for the power operation of a chain wrench at any location along the work stand, using a hydraulic cylinder to power the chain wrench while a clamp assembly, using a clamping chain and a chain tightener secures the other part of the pump against the rotation. None of these power apparatus is particularly suited for unthreading the impellers of pumps. In particular, none of these apparatus is adapted to break the threaded connection of impellers of various sizes and right or left-threaded connection. According to the invention an apparatus for uncoupling a threaded joint between a member and a shaft, comprising a housing having an upper surface for supporting the joint, a longitudinal beam secured to the housing, a vertically upstanding support mounted on the beam in alignment with the housing for supporting the shaft, a hydraulic cylinder pivotally mounted on the side of the housing remote from the support, flexible means associated with the rod of the cylinder for engaging the member, means for securing the shaft and motor means for activating the hydraulic cylinder to tighten the flexible means to apply torque to the member to uncouple the joint, characterised in that for use in uncoupling an impeller from a pump or turbine shaft, the means for securing the shaft is mounted on the vertical support and the flexible means which is secured to the rod of the cylinder, carries hooking means spaced from the rod and constructed directly to engage a blade of the impeller whereby the torque to uncouple the joint is applied by means of the hooking means acting at a spaced location from the axis of the threaded joint. One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of the apparatus, without an impeller in place; Figure 2 is a right hand end view of the apparatus shown in Figure 1; Figure 3 is a left hand view of the vice and trolley assembly shown in Figure 1; Figure 4 is a side view of the vice and trolley assembly shown in Figure 3; Figure 5 is a perspective view of the hook used in the invention; and Figure 6 is a perspective view of the apparatus shown in Figure 1 with an impeller in place. Referring to Figure 1, the apparatus includes a trolley beam 1, constructed for example of one hundred millimetre steel channel. Mounted in the trolley beam is a vice and trolley assembly 2, consisting of a trolley assembly 3, carriage assembly 5, and vice assembly 7. The vice and trolley assembly is able to be rolled to any position on the trolley beam by virtue of carriage wheels 6 shown in Figure 4. Trolley stop 11 prevents the carriage from rolling out of the trolley beam and also functions as legs for the trolley beam. Fixed to the end of the trolley beam opposite from the trolley stop is a work stand or table 9, consisting of a housing 10 and a cradle 12. Housing 10 enclose an electric motor for powering a hydraulic pump, and a reservoir of hydraulic fluid. The pump activates the hydraulic cylinders to be described hereafter, using controls 14, all in a known fashion. Referring to Figure 2, hydraulic cylinder 16 is the main cylinder and is used for breaking the threaded coupling. It is pivotally attached to the housing 10 at 18 by means of a pin through the clevis of the cylinder running through an ear attached to the housing and secured by a cotter pin. Stops 20 and 22 limit the extent to which the cylinder is able to pivot. A slot 24 in the housing allows the hydraulic connection to the cylinder 16 to enter the housing at any angle of the cylinder. The cylinder has the usual rod 26 attached to the end of the piston in the cylinder. To the end of the rod is attached a chain 28. Referring to Figures 3 and 4 the vice and trolley assembly consists of the trolley assembly 3 mounted on carriage 5 having four carriage wheels 6. The vice assembly 7 is vertically slideable within the trolley assembly 3 so that the height of the vice may be adjusted. The height may be power-adjusted using a hydraulic cylinder pivotally secured to the base of the trolley assembly with its piston rod attached to the vice assembly. The height of the vice assembly may then be automatically be controlled by controls 14. The trolley assembly has an eye 30 to which is secured chain 32. On the opposite side of the trolley assembly is fixed a hook 34 for receiving the chain. The vice assembly consists of a V-shaped vice plate 35 shaped to receive the shaft of the impeller, a V-shaped plate 36 having teeth for gripping the shaft of the pump, and a V-shaped plate 38. An angle 33 of approximately 10° is formed between the upper edge of the shaft 31 which supports the vice assembly and the horizontal. The entire vice assembly, consisting of the vice plate 35, teeth 36 and pivot plate 38 is mounted on a horizontal pivot pin at right angles to the lengthwise direction of the trolley beam which allows the vice assembly to pivot back an angle 10° from the horizontal. This allows the vice assembly to obtain a strong grip on the coupling or shaft despite the fact that the pump rotating assembly may not be perfectly level. Also, it has been found to be preferable to have the pump rotating assembly lower at the end remote from the impeller when breaking the thread in order to diminish the impeller angle on the pulling hook. The hook 29 used in the apparatus to hook the impeller blade is shown in Figure 5. In order to protect the blade, a resilient wooden or rubber slotted insert 37 may be used to place over the impeller blade. In operation, the pump assembly 40 is placed with the impeller blade 42 projecting over the end of cradle 12 as shown in Figure 6 and the other end of the pump shaft resting on vice assembly 7. The trolley assembly is positioned at the appropriate distance from the work stand or table 9 by rolling it along the trolley beam. The hydraulic cylinder in the vice and trolley assembly is activated to raise or lower the vice assembly until the pump shaft is approximately level. Hold-down chain 32 is then led over the shaft or coupling and hooked onto hook 34. The hydraulic cylinder is then activated to raise the vice assembly and tighten the shaft or coupling against the teeth 36 of the vice assembly. Main cylinder 16 is pivoted to one side or the other of its range of travel depending on whether the impeller is a right or left-hand thread. The chain is then led over the impeller blade and hook 29 hooked over one of the blades. The cylinder is then activated to tighten the chain and uncouple the threaded coupling. It will be seen that the invention is particularly adapted for unthreading the threaded connection of an impeller of varying size and shape. The movement of the carriage assembly along the trolley beam and the raising or lowering of the vice assembly shaft allows for adjustment to the various pump assembly sizes. Further, the pivoting capacity of the main cylinder 16 allows it not only to adjust to impellers of various diameters, but also to impellers having right or left-handed threads.

Claims: An apparatus for uncoupling a threaded joint between a member and a shaft, comprising a housing (10) having an upper surface (12) for supporting the joint, a longitudinal beam (1) secured to the housing (10), a vertically upstanding support (2) mounted on the beam (1) in alignment with the housing (10) for supporting the shaft, a hydraulic cylinder (16) pivotally mounted on the side of the housing (10) remote from the support (2), flexible means (28) associated with the rod (26) of the cylinder (16) for engaging the member, means (30, 32, 34, 36) for securing the shaft, and motor means for activating the hydraulic cylinder (16) to tighten the flexible means (28) to apply torque to the member to uncouple the joint, characterised in that for use in uncoupling an impeller (42) from a pump or turbine shaft, the means (30, 32, 34, 36) for securing the shaft is mounted on the vertical support (2) and the flexible means (28) which is secured to the rod (26) of the cylinder, carries hooking means (29) spaced from the rod (26) and constructed directly to engage a blade of the impeller (42) whereby the torque to uncouple the joint is applied by means of the hooking means (29) acting at a spaced location from the axis of the threaded joint. The apparatus of claim 1, characterised in that the support (2) is movable along the longitudinal beam (1). The apparatus of claim 1 or 2, characterised in that the height of the support (2) is adjustable. The apparatus of claim 1, 2 or 3, characterised in that the housing (10) further comprises stop means (20, 22) to limit the degree of pivoting of the hydraulic cylinder (16). The apparatus of any preceding claim, characterised in that the hydraulic cylinder (16) is mounted at the base of the housing (10) with the axis of rotation of the pivotal movement lying along the longitudinal centreline of the longitudinal beam (1). The apparatus of claim 3 or claim 4 or 5 as appendant to claim 3, characterised in that the height of the support (2) is adjustable by means of a hydraulic cylinder. The apparatus of any of claims 1-6, characterised in that the means (30, 32, 34, 36) for securing the shaft comprises flexible means having a first end secured to the support (2) and a second end adapted to be removably secured to the support (2).

Inventors: CHAREST, JOSEPH ROLAND JEAN-PAUL LAURENT
Applicants: ZEE IMPELLER BREAKER INC.
Application year: 1987
Main classification: B23P19
IPC codes: B25B13, B23P19, B25H1, B25B21