Modulating refrigerant flow through a motorized expansion valve

摘要

A motorized refrigerant valve has a spool axially moveable in a valving bore in a valve body for controlling flow from a high pressure inlet for expansion and discharge at substantially reduced pressure to an outlet in the valve body. A ball screw is provided on the remote end of the spool and the ball screw is driven by a rotating shaft of a stepper motor attached to the valve body to provide fine resolution for linear movement of the spool in the valving passage. A separate isolated passage through the valve body is connected to receive evaporator discharge flow and has a thermistor sensing temperature therein and provides a temperature signal to an electronic controller for providing a driver signal to the stepper motor. The stepper motor and ball screw drive to the spool provide the desired modulation of refrigerant flow in response to the signal from the controller.