GB1368689A - Pressure-regulated diaphragm pumps - Google Patents

Abstract

1368689 Diaphragm pumps O TUCHENHAGEN 21 Jan 1972 [21 Jan 1971] 3040/72 Heading F1A In an hydraulically operated diaphragm pump for pumping a liquid which contains suspended solids (e.g. dirty water) from A to C through non-return valves 7, 9 and a tank 11 containing compressed air above the water level 13 means are provided for varying the quantity of hydraulic fluid (clean water) on the primary side 3 of the pump, so as to reduce down to zero the pump delivery rate and delivery pressure when the pressure in tank 11 exceeds a predetermined limit. On each movement to the left of piston 5 clean water is drawn from container 34 through lines 18a, 18, 21 and 28 past the open valves 14, 19 and 22 into the primary side 3 of the pump chamber, the spring-loaded valve 22 having been opened by the movement of diaphragm 1 to position 1a. On each movement to the right of piston 5 the diaphragm moves to position 1b to pump dirty water, whilst clean water is expelled from primary side 3 through line 29 and non- return valve 30 back to container 34. When the pressure in tank 11 is too high, member 15 (a diaphragm or piston) first throttles then closes valve 14 to reduce the clean water intake to primary side 3. Since a constant volume is expelled past valve 30 on each move to the right of piston 5, the diaphragm therefore loses its stroke and the pump its delivery capacity. A safety valve 35, for relieving the primary side of the pump in the event of a blockage in the secondary side or failure of the valve 30, is provided. A plurality of pumps as described above may be combined by arranging for them to share at least one common element such as a tank or reciprocating piston, but in all cases each primary side is provided with an individual safety valve 35.