Abstract: An assembly for drivably connecting a shaft to a bore includes a member having a bore, wherein a keyway is included in the bore having a semi-circular cross section. A shaft is provided which is configured to have a non-interference fit in the bore, and a surface of the shaft is formed with a keyway having a rectangular cross-section. A unitary component is provided, and is adapted to connect the shaft to the bore of the member and to allow driving forces to be transmitted between the shaft and the bore. The unitary component includes engagement means formed on an inner surface thereof which enables the component to be coupled to the keyway in the shaft. The unitary component also includes an integral key having a semi-circular outer surface corresponding to and adapted to engage the semi-circular keyway formed in the bore.

Abstract: A shaft 44, 144, 145 is conventionally driveably connected to a bore 46, 146 by a steel key of rectangular cross-section. Where the shaft is of smaller diameter than the bore, a slotted nylon sleeve is fitted between them and a tall steel key extends through the slot. Failure of both standard and tall keys can occur for various reasons. A unitary component 50, 162, 163 of suitable plastics material or non-ferrous metal is therefore proposed. This component essentially includes an integral key 56, 174 of curved cross-section adapted to engage in a mating keyway 176 formed in the bore. Where the shaft 44 and bore 46 are nominally of the same diameter, the component 50 consists also of an integral key 52 of rectangular cross-section adapted to engage in the conventional keyway 48 in the shaft.

Abstract: A high pressure multi-stage centrifugal pump with an axially split casing (10) and a number of impellers (14) carried by a drive shaft (12) has inter-stage bushings (24) and rings (22) for sealing each side of each impeller. Each bushing (24) or ring (22) is conventionally prevented from rotating by a radial pin protruding from the lower half of the casing (10) into an axial slot in the periphery of the bushing or ring. The pin is necessarily small and is liable to shear, difficult to engage in the slot and, in cases where the bushing (24) or ring (22) is diametrically split, does not allow rotation of the lower half for its removal without lifting the shaft (12). To avoid all these disadvantages, without introducing any risk of leakage, a tangential pin (32) is fitted in a blind hole (34) in the casing (10) so that its exposed end (37) is flush with the joint face (28) of the casing and abuts against a shoulder ( 44) formed by a recess (38) in the periphery of the bushing (24) or ring (22).

Abstract: An arrangement for applying a back pressure to a shaft seal of a mechanism such as a pump comprises a piston slidable in a cylinder one end of which communicates with the fluid being pumped and the other end of which contains oil communicating with a sealed chamber on that side of the seal remote from the fluid. Hitherto, the piston has created a preponderance of the back pressure over the pressure of the fluid by virtue of its weight. This preponderance has been very small, and the rolling diaphragm seal needed on the piston has been easily ruptured if the oil has been lost, thereby allowing possibly hazardous fluids to escape. A greater preponderance of the back pressure, allowing the use of a stronger type of piston seal, is provided by urging the piston towards the other end of the cylinder by a spring as well as by the pressure of the fluid.