Expansion Valve Actuator

Valves are used in numerous applications to control the flow of heating or cooling fluids in an HVAC system. An expansion valve is a flow-restricting device in refrigeration systems that causes pressure drop of the working fluid. When controlled properly, an expansion valve keeps the evaporator active throughout its operation to optimize efficiency. Electric expansion valves use can stack motors with gearing mechanisms to convert rotational motion into linear actuation which, in turn, controls the valve piston. These valves can be subject to higher ambient operating temperatures while in operation.

A leading HVAC company approached Portescap to develop a new valve design to improve reliability and precision. Portescap’s prototype team developed several design options in collaboration with the customer in order to identify the best motor and gearing combination that met the desired valve performance requirements, including matching the insulation class and temperature requirement. A solution combining a 42mm can stack stepper motor with an appropriate gearing system provided the required 70N force needed to move the expansion valve piston. This resulted in a cost-effective and compact design that successfully met the customer’s requirements.

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