The control outlet can be located adjacent either the supply inlet or the supply outlet. The control outlet can include a control passage having an inner opening communicating with an outer opening near the exterior of the demand valve body. The outer opening of the control passage can be adapted for securing the demand valve to a control line. The inner opening of the control passage can open into the supply line passage within the demand valve body. The inner opening can include a control valve seat. The control valve seat can be located in a plane transverse to the direction of supply line flow through the supply line passage.

The valve mechanism can include a demand valve shaft. The demand valve shaft can extend along the supply line passage and the control valve member can be located at one end of the shaft. MULTI-FUNCTIONAL WATER PUMP CONTROL VALVEThe valve mechanism can also include a control valve member biasing means. The control valve member biasing means can operate on the valve mechanism so that the control outlet is normally closed. The valve mechanism can include a supply line valve member movable in response to flow of fluid between the supply inlet and the supply outlet.Bellow Seal Valve The supply line valve member can be located on the demand valve shaft in the supply line passage downstream of the control valve member to intercept fluid flow through the supply line passage. The supply line valve member can be biased toward a supply line valve seat. Advantageously the supply line valve member is an annular pressure plate extending transversely of the valve shaft. In one form the pressure plate can be seated when the control valve member is seated. In another form the pressure plate can be spaced from the supply line valve seat when the control valve member is seated. Instrument Manifolds The supply line valve seat can be of slightly greater diameter than the pressure plate to permit a predetermined minimum flow of fluid through the supply line passage between the pressure plate and the supply line valve seat. Alternatively, the pressure plate can seat to form a fluid tight seal. In this embodiment the pressure plate can include a plurality of apertures or holes to allow a predetermined minimum flow of fluid through the supply line passage. The aperture or hole size can be made adjustable by using a needle valve or camming closure to vary the aperture size. A supply line valve member biasing means can bias the supply line valve member toward the supply line valve seat. The control valve member and the supply line valve member can be biased by the same biasing means or can be biased independently. A biasing adjustment means can be used to vary the amount of bias on the supply line valve member and/or control line valve member.

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2012-01-05

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