GB326817A - Improvements in or relating to apparatus for delivering measured quantities of liquids - Google Patents

Abstract

326,817. S.I.A.M., Ltd., and Lewis, F. W. Dec. 18, 1928. Single-acting piston pumps; measuring devices; drip, preventing; valves and valve seats, arrangement of; priming.- In a means for delivering measured quantities of a liquid, the pump is attached to a hollow standard 1 fitted above a storage tank. The pump comprises a main piston 15, attached to a piston rod 14, upon which is machined a rack 16 engaging a pinion 17, the latter actuated by an external handle. The suction pipe 3 is fitted with a non- return valve (not shown) and delivery takes place through an aperture 31 which is fitted with a valve 34 to prevent drips. On delivery the pressure on the piston 33 raises the valve 34 which is normally kept closed by the spring 35. The pump is calibrated to deliver a desired quantity, the stroke being limited by an adjustable stop 37 that is sealed after calibration. Within an extended sleeve 21 on the main piston 15 is an auxiliary piston 22 which aids to keep the pump primed. During the first part of the suction stroke the auxiliary piston 22 travels within the sleeve 21 and draws air and liquid through the spring loaded non-return valve 25. At the commencement of the delivery stroke movement of the auxiliary piston within the sleeve causes the air and liquid in the sleeve to pass through the ports 26 and non-return valves 27 to the back of the main piston and eventually return to the storage tank through the pipe 12.