Gas Valve and Method of Control

摘要

A stepper-motor gas valve control is disclosed that includes a main diaphragm in a chamber that controllably displaces a valve relative to an opening in response to changes in pressure, to adjust fuel flow through the valve. A servo-regulator diaphragm is provided to regulate flow to the main diaphragm, to thereby control the rate of fuel flow. A stepper motor is configured to move in a stepwise manner to displace the servo-regulator diaphragm, to control fluid flow to the main diaphragm. A controller mounted on the stepper-motor regulated gas valve control receives and converts an input control signal from a heating system to a reference value between 0 and 5 volts, and selects a corresponding motor step value. The control responsively moves the stepper-motor in a step wise manner to displace the servo-regulator diaphragm and thereby regulates the rate of fuel flow through the valve.

主权项

1. A gas valve unit for controlling the rate of gas flow in a gas-fired appliance, comprising:
a main diaphragm chamber; a main diaphragm in the main diaphragm chamber that controllably displaces a valve element relative to a valve opening to adjust a gas flow rate in response to changes in pressure in the main diaphragm chamber; a servo-regulator diaphragm configured to regulate fluid flow to the main diaphragm chamber; a stepper motor configured to move in a stepwise manner to bias the servo-regulator diaphragm for regulating fluid flow to the main diaphragm chamber to cause the displacement of the main diaphragm and the valve element to control the gas flow rate through the gas valve unit; a sensor that provides an output indicative of a pressure at an outlet of the gas valve unit; and a valve controller for controlling the stepper motor to cause the valve element to be displaced relative to the valve opening for controlling the gas flow rate to the outlet, the valve controller being selectively configurable to control the stepper motor movement to provide a select opening flow rate profile that is a function of outlet pressure over time, wherein the valve controller is configured to control an input signal to the stepper motor based in part on the output from the sensor that is indicative of the pressure at the outlet.