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The JASC Three-Way Purge Valve was originally created for a large industrial gas turbine
manufacturer who was experiencing multiple check valve issues on their dual fuel turbine
engines.
In the mid-1990s, after the successful development of the JASC Three-Way Clevis Servo Valve,
we were approached by a gas turbine manufacturer
who asked us if we could do something similar for them
on a dual fuel gas turbine.
We said we certainly thought so.
They gave us the specification.
We replied to the specification and they liked the design.
So we launched off on the design. And it combined the features of the
purge air check valve and the features of the liquid fuel check valve into one package
with a much more stable design. However, in the meantime
There were some issues that were severe in the field that didn't allow
the engines to be run by the users for any long period of time, so this gas turbine manufacturer
also approached JASC a second time
asking if we had some solution for the check valve instability problems.
We came up with the design that they are using today in the field and it consists of what we call
an inverted spool, which incorporated a Helmholtz resonator and a way of sensing the pressure that made the device very stable.
Design work then resumed in earnest on the Three-Way Purge Valve. JASC competed against
three other companies and after all the qualification testing was completed JASC's Three-Way Purge
Valve was the only valve to successfully pass all the requirements. JASC was awarded the
contract and serial production of the Three-Way Purge Valve began.
JASC's Three-Way Purge Valve is a spool valve. While spool valves have been used in
other applications, JASC innovated a solution that utilizes the spool configuration to flow
air and fuel in a single package, an industry first.
This design was also chosen because it opens up a large flow passage resulting in low pressure
drops for high efficiency and the ability to pass large particulate contamination. The
spool is contoured for smooth air and fuel flow around the spool itself.
The valve's default position is to flow purge air. Liquid fuel pressurization will
shuttle the spool from purge air mode to fuel mode. A piston activated by pilot air can
also control the spool's movement when switching to liquid fuel.
JASC designed seals specifically for this application—one in which the valve may have
to sit dormant for up to a year without leakage and then switch immediately to flow liquid
fuel. A special polymer was developed that would be contamination tolerant and maintain
its sealing capability. The seal is completely disengaged as the spool moves away from the
seal and is protected from the flow path, whether the valve is flowing air or fuel.
JASC's Three-Way Purge Valves are designed to have a long operating life and can be refurbished,
resulting in a lower total cost of ownership.
As an original equipment manufacturer, JASC has built and shipped over 4,000 Three-Way
Purge Valves.
JASC rigorously tests every Three-Way Purge Valve individually to ensure each one conforms
to the unique performance specifications defined by the customer.
The JASC Three-Way Purge Valve is contamination tolerant, vibration resistant, and provides
ANSI Class 6 zero-leak seals.
There are a number of turbine engine configurations, some utilizing up to 28 JASC Three-Way Purge
Valves per engine.
JASC Three-Way Purge Valves are manufactured for a variety of flow rates and crack pressures
and for heavy fuel usage.
Development of the JASC Three-Way Purge Valve has resulted in a series of other design configurations
including the Combining Valve which includes purge air, fuel distribution and fuel delivery
functions into a single water cooled package and the Water Cooled Three-Way Purge Valve.
The JASC Water Cooled Three-Way Purge Valve was developed in response to liquid fuel coking
that will occur when valves are on an engine and exposed to heat for an extended period
of time while the turbine is operating on gas fuel.
Internally, the JASC Water Cooled Three-Way Purge Valve is identical in design to the
standard JASC Three-Way Purge Valve.
The JASC Water Cooled Three-Way Purge Valve incorporates an outer water jacket and water
cooled *** that keeps the valve cool enough to eliminate coking.
For more than two decades, the JASC family of industrial valves has continued to provide
affordable, dependable and innovative solutions for a wide variety of customers and applications.
JASC's mission is to become the preeminent supplier of valves and controls worldwide.