Spring valve implemented flow control valves

An improved low flow impedance three-way flow control valve of the type having a housing;

• an axially oriented inlet port located in a first end of the housing;
• first and second annularly oriented output passages disposed within the housing and fluidly isolated one from another by a central housing bulkhead, the first annularly oriented output passage being located proximate to a first end of the housing and the second annularly oriented output passage being located proximate to the second end of the housing;
• and an axially moving valve spool, the valve spool being positioned by a valve stem and including an axially oriented flow channel, wherein the improvement comprises:
• a rolling diaphragm located proximate to the central housing bulkhead for fluidly isolating the output passages one from another and constraining the valve spool for axial movement within the housing;
• first spring valve means captured between the valve spool and a shoulder located within the first end of the housing for selectively metering a flow of fluid from the inlet port to the first output passage via a round edged helical orifice formed between the open coils of the first spring valve as a function of the instant axial position of the valve spool and the differential pressure therebetween;
• and
• second spring valve means captured between the valve spool and the second end of the housing for selectively metering a flow of fluid from the inlet port to the second output passage via the flow channel and a round edged helical orifice formed between the open coils of the second spring valve as a function of the instant axial position of the valve spool and the differential pressure therebetween.

A method of controlling low impedance flow control valves, wherein the method comprises the steps of:

• providing at least one interruptible fluid flow path to a like numbered output port or ports from an input port;
• providing means for substantially interrupting fluid flow through a single such fluid flow path or alternately through multiple such fluid flow paths;
• and
• continually cycling the means for substantially interrupting fluid flow in a low frequency pulse width modulated fashion.

An improved low flow impedance three-way flow control valve assembly, comprising:

• first and second coupled and oppositely directed two-way valves;
• respective first and second generally annularly oriented output passages for receiving selectively apportioned fluid flow from the first and second two-way valves;
• means for mechanically coupling and physically positioning the first and second two-way valves;
• and
• means for mechanically driving the means for mechanically coupling and physically positioning.