Abstract: Improved flow control valves are disclosed which are exceedingly accurate in maintaining a constant predetermined flow rate regardless of inlet and outlet pressures. The valves are preferably designed to enable them to be fabricated almost entirely from suitable polymeric composition materials. One embodiment disclosed is extremely well suited for ultra-pure applications which require extreme care to avoid any possible contamination of the liquid flowing therethrough. Another embodiment is disclosed which is designed to achieve substantially zero leakage flow thereby rendering it particularly well suited for use in applications requiring exceedingly precise flow control and in particular relatively low flow rate applications wherein leakage flow is of greater significance.

Abstract: An adjustable ratio mixing valve is disclosed which incorporates an automatic pressure compensating arrangement whereby the fluid pressure immediately upstream of each of the metering orifices is maintained in substantial equilibrium. This arrangement then enables the respective fluids to be intermixed in any desired volumetric ratio by merely suitably adjusting the open flow area of the metering orifices. In one embodiment the metering orifices are each externally adjustable to enable relatively easy changes in the mixing ratio to be made and may also be interconnected whereby flow volume may be changed while maintaining the desired present mixing ratio. In another embodiment, rapidly acting on/off valving is provided integral with the valve so as to render it uniquely suited for cyclic fluid flow.

Abstract: Improved flow control valves are disclosed which are exceedingly accurate in maintaining a constant predetermined flow rate regardless of inlet and outlet pressures. The valves are preferably designed to enable them to be fabricated almost entirely from suitable polymeric composition materials. One embodiment disclosed is extremely well suited for ultra-pure applications which require extreme care to avoid any possible contamination of the liquid flowing therethrough. Another embodiment is disclosed which is designed to achieve substantially zero leakage flow thereby rendering it particularly well suited for use in applications requiring exceedingly precise flow control and in particular relatively low flow rate applicatins wherein leakage flow is of greater significance.