GB1028003A - Improvements in or relating to reciprocating pumps - Google Patents

Abstract

1,028,003. Reciprocating pumps. C. A. SWARTZ. April 19, 1963 [April 25, 1962], No. 15437/63. Heading F1A. In a reciprocating pump, Fig. 1, which may be used for pumping radio-active liquids, the liquid being pumped is isolated from a reciprocating actuating plunger 24 and packing 28 in a housing 10 by a surge column 22 of working liquid, which may be oil or water, and a bellows 14 which may be of metal and which has an end sealing cap 20. The other end of the bellows has a plate 16 provided with three ports through which the working liquid is reciprocated by the plunger 24 to and from the interior of the bellows 14 to thereby cause the latter to reciprocate within a block 8 and pump liquid from an inlet 1 having a valve 4, to an outlet 2 having a valve 6. A lens joint 12, or a raised face, tongue and groove, ring, or male and female joint, is provided between the housing 10 and block 8. In order to maintain a predetermined maximum pressure differential across the bellows 14, the pressures of the working liquid and the pumped liquid are communicated through conduits 48 and 44 to a balancing device 42 containing a diaphragm 50 biased by a spring 57 to close a valve 56. The valve 56 opens when the pressure of the working liquid is high to drain off some of the working liquid which may then be passed to a reservoir 54. The latter is pressurized preferably to approximately the suction pressure of the pumped liquid, and an associated valve 52 allows replenishment of the working liquid if its pressure is low. A pressure relief valve 46 is provided for the pumped liquid. The stroke of the bellows 14 may be varied by adjustment of a sleeve 36 screwed into the end plate 16 against one end of which the cap 20 may abut, and by adjustment of a nut 38 screwed on one end of a rod 34 which slides freely in a bore through the sleeve 36. In an alternative embodiment, Fig. 4 (not shown), an intermediate spool piece is provided between the housing and block with lens joints at each of its ends and having a bore the diameter of which is preferably equal to the diameter of the bores in the associated housing and the block. Furthermore, the bellows has three centralizing shoes spaced around the periphery of its end sealing cap and is positioned at one of the ends of the spool piece either to protrude into the block, as in Fig. 1, or into the spool piece itself, in which case the conduit communicating the pumped liquid pressure to the pressure balancing device may be connected to the spool piece. Cooling or heating means in the form of a coil wound around the spool piece may be provided and such means may be applied to any part of the pump. In a second alternative embodiment, Fig. 6, either the end of bellows 82 nearest the block 78 or the opposite end is mounted on a composite plunger 74 having a shoulder 88 which maintains the pressure of the working liquid within the bellows 82 in accordance with the pressure of the liquid being pumped. The pump may have any number of cylinders with the blocks cast or forged individually or in one piece and with integral or separate suction and discharge manifolds.