The manufacture of urethane foams, for example, involves supplying two or more reactive components in accurately metered proportions to a mixing device from whence the mixed components are deposited in a suitable mold wherein the mixture reacts to produce the polyurethane foam. These components are relatively viscous and usually contain solid fillers and solid impurities and are desirably maintained in constant circulation through a closed loop leading from and returning to the component supply tank.WATER POWER CONTROL VALVE A suitable supply conduit connected to the loop feeds the component to the mixing device at a predetermined pressure. The fluid pressure is generated by a suitable pump located in the loop between the supply tank and the supply conduit and is controlled by a control valve located in the loop between the supply conduit and the supply tank.

In the manufacture of polyurethane foams, the ability to control the loop pressures is an important requirement since the maintenance of a set pressure consistently in the loop is necessary for metering component outputs correctly.

A primary function of the control or throttle valve in any processing loop as above described is to create a restriction which in turn controls the back pressure existing between the pump and the valve. Reducing Valves Given the same flow rate, the component or material velocity through the valve must vary as the passage diameter or dimension therethrough changes. Sensitivity, fouling and consistency of pressure are dependent on the smoothness of the material velocity transition through the valve. Abrupt restrictions, characteristic of throttling valves in general, promote turbulent flow and uneven pressure conditions.

It is the principal object of this invention to provide a control or throttling valve which is simple in construction and permits smooth linear or laminar passage of material therethrough whereby uneven pressures due to abrupt restrictions and turbulent material flow are avoided.

A further object of the invention is to provide a control or throttling valve through which smooth linear or laminar flow is accomplished, which is essentially non-fouling, which minimizes pressure losses caused by valve and valve orifice configurations and which is essentially free of deterioration in efficiency and effectiveness due to corrosion caused by corrosive component ingredients such as toluene diisocyanate in urethane precursor components.

Another object of this invention is to provide a throttling valve construction having the above advantages which may be made by a relatively simple modification of a standard ball valve.

These and other objects are accomplished by the provision of a precision fluid control ball valve including a ball having an opening therethrough with an inlet end and an outlet end which is rotatably disposed in a housing having an inlet port and an outlet port. The inlet end of the ball opening is circular and is movable with respect to the circular housing outlet port so that the outlet opening of the valve may be infinitely varied between a fully open and a fully closed position. Instrument Manifolds The outlet end of the ball opening is sufficiently larger so that the inlet to the ball opening is fully open for all settings of the valve between the fully open and fully closed positions and the ball opening progressively increases in dimensions preferably in funnel-like fashion from the outlet end to the inlet end so that the fluid flows substantially linearly through the valve for all settings of the valve between its fully open and fully closed positions and whereby a laminar flow profile through the valve is established.

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2012-01-04

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