Patent GB-512897-A (GB)
Title: Improvements in or relating to liquid feeding apparatus
IPC: C02F1/68
Filed: 1938-03-16
Abstract: 512,897. Diaphragm pumps: liquid-pressure engines. WALLACE & TIERNAN CO., Inc. March 16, 1938, No. 8144. Convention date, May 5, 1937. [Class 102(i)] [Also in Group XXIX] An apparatus for feeding liquid to a body of liquid under pressure, e.g. chlorinating solution into a water main, comprises a diaphragm, pump with a chamber at the back of the diaphragm to which liquid from the body of liquid, or a separate source, is supplied for exerting force on the diaphragm during the delivery stroke whereby little or no externally supplied power need be applied to the diaphragm and the life of the diaphragm is conserved. In the 'form shown in Fig. 1, water flows constantly from the main through a differential valve and a port 56 into a chamber 54 thence through a port 76 and a tube 72 to waste until a slidable shaft 86, operated through a bell-crank 94, 98 and a connecting-rod 108 from an eccentric 110 driven by an electric motor, closes a slidablymounted valve 88 so that the chamber 54 is rapidly filled and then displaces the housing 84, the tube 72 and the centre of a flexible diaphragm 20 thereby expelling a charge of treating liquid from the chamber 23 into the main. On the return stroke of the bell-crank, the valve 88 opens, thereby allowing water to flow idly through the chamber 54, and, the housing 84 is retracted so that the diaphragm draws a fresh charge of treating liquid into the chamber 23. The quantity of liquid delivered may be varied by adjusting the rod 108 along the slotted arm 98, provided with a calibrated scale 118. The diaphragm 20 is clamped between a flange 42 on the cup 40 and a block 22 by means of a clamping head 46 and a circular aligning member 48, studs 44 on the cup passing freely through the corners of the block 22 and head 46. The nuts 50 are moderately tightened and the member 48 is then clamped against the block by a screw 52 having a reduced end 53 engaging loosely in a hole in the member 48. In the modification shown in Fig. 3, a slidable frame 184, adapted to be moved relatively to the tube 72 to close the end thereof by means of a valve disc 188 and then move the tube to operate the diaphragm 20, is connected to a diaphragm 196 and carries a pivoted lever 222, controlled by a cam 214, rotated by a water meter in the main, and controlling a valve 208 in the outlet of the diaphragm chamber 202, to which water from the main is supplied through a pipe 212. With the valve 208 closed, the diaphragm 196 is operated to effect the pumping stroke until the lever 222 drops to a low point of the cam thereby allowing the valve 208 to open and the return stroke to be effected by a spring 187. The diaphragm 196 is displaced in exact proportion to the speed of the cam. The lever 222 comprises two separately pivoted parts 226, 228 normally held in contact by a spring 232. Relation movement of the parts prevents damage to the cam or water meter as by a stoppage of the water flow to the chamber 202 and allows escape through the valve 208 of water in excess of that required for displacing the diaphragm 196. A slidable stop 234 is adjustable by means of a screw spindle 240 for varying the length of stroke, a pointer 248 and a dial 250 being provided. In the modification shown in Fig. 5, the outlet 308 of the chamber 302 of the driving diaphragm 196 is controlled by a valve disc 310 on a pivoted lever 312 adapted to abut a spring- pressed diaphragm 316 closing a chamber 318, to which water is supplied from the main through a reducing valve and which has an outlet 322 provided with a slidable valve 324 controlled by a rod 328,336 extending through a spring-pressed washer 340 in a cavity 346 in a support 344 carried by the frame 184. At the end of a return stroke, the valve 324 is closed and the diaphragm 316 is operated to rock the lever 312 and close the valve 310 with a snap action, the rod 328 pressing the washer 340 back against the spring 348. The frame 184 is then driven by the diaphragm 196 until the washer 340 re-engages the bottom of the cavity 346 thereby releasing the rod 328 and allowing the valve 324 to open, the diaphragm 316 to snap back and the lever 312 to rock and open the valve 310 so that the return stroke is effected by the spring 87. The pump delivery may be varied by adjusting the differential valve in the supply pipe to the chamber 302, or may be varied automatically in accordance with the flow in the main by creating a minor flow from the latter to the chamber 302 as by means of a venturi tube. Fig. 9 shows a valve control by which the water supply to the chamber 54 may be cut off during the return stroke of the pump. The inlet and outlet valves 510,512 are carried by a rod 508 pivoted to a lever 504 connected by a member 506 to a reciprocating element so that the valve 512 is closed at the beginning of a pumping stroke and the valve 510 at the beginning of a return stroke.