Modulating expansion valve

Details Modulating expansion valve Modulating expansion valve

1999-01-08

2001-06-12

Walton, George L. (Department: 3753)

Valves and valve actuation

Fluid actuated or retarded

Pilot or servo type motor

C251S030050, C251S063000, C251S063500, C251S121000, C251S205000

Reexamination Certificate

active

06244561

ABSTRACT:

The invention relates generally to expansion valve utilized in refrigeration systems and, more particularly, to an expansion valve for a refrigeration system controlled by a pair of electrically operated solenoid valves.
BACKGROUND OF THE INVENTION
Refrigeration systems consist of a refrigerant utilized in a cycle including a compressor, a condenser, an expansion valve and evaporator. While an expansion valve may potentially be as simple as an orifice, modern day refrigeration systems usually monitor the entire refrigeration cycle to optimize efficiency. Optimizing the efficiency in the condenser and in the evaporator entails providing an expansion valve having not only open and closed positions, but also a variety of partially open positions and a means for providing the correct optimum flow of refrigerant through the expansion valve. Presently known control apparatus used to operate a modulating expansion valve includes the use of an electric motor having an annular stator positioned on top of the valve and an armature positioned inside the hollow interior of the stator having a shaft in the center thereof which turns through a worm gear to raise and lower a regulating piston through the valve port. This type of motorized operator requires the use of shaft seals between the motor and the piston and thus provides an additional leak path to the atmosphere from the refrigeration system.
A need has arisen for an improved expansion valve for use in a refrigeration system that avoids the complexities of a motor operated expansion valve while providing simplicity of operation and a semi-hermetic seal between the valve and the atmosphere.
SUMMARY OF THE INVENTION
The invention resides in a modulating valve for use in controlling flow in a fluid system. The valve comprises a housing including a high pressure fluid inlet, a low pressure fluid outlet and a movable valve body positioned between the inlet and outlet. The valve body is adapted to move to open and close the valve and is biased in one of the open or closed positions. The invention further includes means having a first electrically operated pilot valve therein for providing controlled flow of fluid from the high pressure inlet of the housing to a portion of the valve body (above the piston) tending to move that valve body in a direction opposite its biased position. The invention further resides in means including a second electrically operated pilot valve for providing a control flow of fluid from the valve body (above the piston) to the low pressure outlet of the housing. This allows the valve body to move in a direction toward its biased position.


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patent: 0020611 (1968-09-01), None

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