GB843935A - An improved valve for controlling the flow of fluid - Google Patents

Abstract

843,935. Fluid-pressure servomotor control systems; valves. HANSEN, A. F. June 29, 1956 [July 6, 1955; Feb. 10, 1956], No. 20229/56. Class 135. A valve comprises a casing, a diaphragm extending across the casing and serving to divide it into two compartments, one of the two compartments being provided with an inlet opening and with an outlet opening, means enabling variations of pressure to be produced in the other one of the two compartments, the diaphragm being so positioned in relation to one of the openings that in the normal position of the diaphragm a part of the diaphragm lying inwardly of its marginal edge engages directly with the rim of the opening and thus acts to keep the opening normally closed and a plate of stiff material applied, to the said part of the diaphragm, the plate being of such size that it extends radially beyond the rim of the opening with which the said part of the diaphragm engages, while leaving the diaphragm with a surrounding marginal part giving the diaphragm freedom to flex, the plate being secured to the diaphragm in such manner as to keep this part substantially flat over an area which also extends radially beyond the rim of the opening. In Fig. 1 the casing 2 is secured to the interior face of one of the side walls of a cistern and has an inlet 7 and an outlet 8 closed by the diaphragm 3 to which is secured the stiffening plate 9. The diaphragm is also provided with a small hole 10 providing communication between the upper and lower compartments of the casing. A hole 12 is formed in the top of the casing 2 and can be closed or opened by a valve member 13 attached by an arm 14 to a float 16. Water entering the casing through the inlet 7 causes the diaphragm 3 to flex upwards permitting a flow through the outlet pipe 8 to fill the cistern. When the water in the cistern reaches a predetermined level the float 16 closes the hole 12 and pressure on each side of the diaphragm equalizes through the small hole 10 whereupon the diaphragm returns to its unflexed position and shuts off the supply through the outlet pipe 8. In a similar arrangement in Fig. 7 the rising level of liquid in the cistern is felt in the tube 50 with a resultant increase in pressure in the compartment 44 above the diaphragm 42. The pressure will rise until it reaches a value sufficient to depress the diaphragm 42 and close the outlet 48, whereupon the diaphragm 3 will be caused to return to its unflexed condition and shut off the outlet pipe 8. In Fig. 3 the pressure acting on the top surface of the diaphragm 3 is controlled by an auxiliary valve 24, which when pressed relieves the pressure above the diaphragm allowing it to flex upwards and open the outlet pipe 20 to water entering at 21 from the cistern 18. On releasing the press button to close the valve 24 pressure will equalize across the diaphragm through the hole 10 and the diaphragm will return to its normal position to close the outlet pipe 20. In Fig. 9 the invention is shown applied to a check valve for use when pumping liquids. On creating a suction in pipe 82 the pressure in compartment 78 is reduced by fluid flowing through the small hole 80 whereupon the diaphragm flexes downwards to allow fluid to flow from the inlet 83. As soon as pumping ceases the pressure across the diaphragm will equalize causing the diaphragm to return to its unflexed condition and shut off the pipe 82. Fig. 11 shows the invention applied as a vacuum valve in cases where a partial vacuum has to be periodically created in an outlet pipe such as in milking-machines. In this embodiment the creation of a suction in pipe 90 unseats an auxiliary valve 94 to cause a reduction in pressure above the diaphragm 86. The diaphragm then flexes upwards to allow air entering the lower compartment at 99 to pass through the outlet pipe 90. As soon as this occurs the vacuum is destroyed in pipe 90 and the auxiliary valve 24 re-seats itself. Pressure then equalizes across the diaphragm through the hole 92 and the diaphragm moves downwards to cut off the outlet pipe 90. The cycle then recommences.