Patent GB-791170-A (GB)
Title: Improvements in or relating to devices for supplying predetermined quantities of a liquid
IPC: G01F11/04
Filed: 1955-08-25
Abstract: 791,170. Delivering measured quantities of liquid. BRAUER, F. Aug. 24, 1956 [Aug. 25, 1955], No. 24465/55. Class 106(5) A device for supplying predetermined quantities of liquid comprises a cylinder 1, Figs. 1 and 2, a piston 17 freely movable in the cylinder on a guide rod 12 which is itself movable longitudinally of the cylinder, abutments 13, 14 on the guide rod on opposite ends of the piston, inlets 4, 5 for liquid under pressure to opposite ends of the cylinder, valve-controlled outlet and overflow openings 23, 24, 25, 26 at each side of the piston, and control means 15, 16 at or near each end of the guide rod for actuating corresponding tripping mechanism 31, 32 for operating the valves controlling the openings 23, 24, 25, 26. In operation, the passage of liquid into the cylinder through the inlet 4 causes the piston to move over the guide rod and so discharge the liquid in front of the piston through the outlet 25. the guide rod is carried along with the piston when the latter strikes the abutment .14 until the control means 16 actuates the tripping mechanism 32 to close the outlet 25 and open the overflow opening 26 whereby the continued discharge from the cylinder passes to the overflow until the piston and guide rod come to rest at the end of the piston stroke; the cycle is continued by admitting liquid to the inlet 5 to cause reverse movement of the piston. A mechanical interconnection is provided between the two tripping mechanisms 31, 32, a valve 8 for directing liquid to either of the inlets 4, 5 and the valves 23, 24, 25, 26. Two treadles are provided for setting the valve 8 in either of its two positions and for pre-setting the tripping mechanisms and valves 23, 24, 25, 26 so that only the appropriate one of these is open at one time. In order to vary the quantity of liquid to be discharged, each of the control means 15, 16 consists of four abutments set at different radial and longitudinal positions on the guide rail 12 which can be rotated by a handwheel 35 at one or both ends to position a selected abutment in the path of the corresponding tripping mechanism. One of the two tripping mechanisms 31, 32 is shown in Fig. 9 and is arranged so that, when one of the treadles is operated to actuate the valve 8, a connecting rod 51 acts through crank mechanism 52, 54, slide rod 56 and swing arm 66 to move a lever 72 forming part of the outlet valve 25 into the open position. At the same time, a slide arm acts upon a swing arm 67 to cause the overflow valve 26 to move to its closed position, and the other tripping mechanism is actuated to close both the valves 23, 24. When, subsequently, the guide rod 12 is moved axially by the piston contacting the abutment 14, the actuators 34 are engaged by one of the control abutments 16 so as to depress trip arms 61, 62 and thereby release the swing arms 66, 67 which are then swung by springs 73, 77 to close the outlet valve 25 and open the overflow valve 26. Modifications consist in the use of a manuallyoperable lever or a single treadle, instead of two treadles, for controlling the valve 8, more or less than four abutments in each group of control elements 16, 17, the mounting of the abutments for longitudinal adjustment on the guide rod, the disposition of the guide rod outside the cylinder axis. and the use of more than one guide rod of which only one need be longitudinally movable. If desired, a servosystem controlled by push-buttons may be provided for operating the valve 8 and pre-setting the tripping mechanisms.