GB839714A - Improvements in or relating to apparatus for delivering preset quantities of fluid - Google Patents

Abstract

839,714. Delivering measured quantities of liquid. PILLIN Ltd., J. B., and BROOKMAN, J. J. Aug. 14, 1958 [Nov. 4, 1957], No. 34382/57. Class 106(5) Free-piston apparatus for delivering fluid in predetermined quantities comprises supply and delivery passages placed alternately in communication with opposite sides of the piston by a manually - operated slide valve, the quantity of fluid delivered being varied by altering the piston stroke by means of an adjustable stop. The piston comprises a centre-plate 20 between cup - washers 19, 21 and a clamping plate 22 screwed on to a bush 17, the lower face of the bush contacting the end of an externallyscrewed member 24 whereby the stroke of the piston may be adjusted to vary the quantity of fluid delivered. After adjustment, the member 24 may be secured by a lock-nut 9 screwed against the outer face of the lower cylinder head 12. The cylinder 10 is held between the upper- and lower heads 11, 12 by bolts 13, a tube 35 being inserted between the heads to provide communication between passages formed in the heads. A piston guide-rod 15 is screwed into the upper cylinder head 11 and extends through packings 23 in the bush 17 and in the interior of the threaded member 24, which may be provided with a leakage draining passage. A valve block 38, secured to the upper cylinder head 11, has three right-angled passages 39, 40, 41, Fig. 4, formed therein and leading from a side face of the block to ports 45, 46, 47 in the bottom face, communicating respectively with the space above the piston, via passages formed in the cylinder head, the outlet port 31, and the space below the piston. A slide valve 49 mounted on the end of an arm 50 of a bell-crank lever pivoted at 51 puts the outlet port 43 on the block 38 alternately into communication with the spaces above and below the piston as the crank is manually operated by a lever 72 and rod 59 to move the valve between stops 53, 54, pressure within the valve cover 77 causing the fluid to flow alternatively via ports 45, 47 and passages 39, 41 in the valve block to opposite sides of the piston. A spring-loaded ball 63 engages detents on the rod 59 to ensure full-stroke movement of the valve 49.