Gas valve and method of control

• US 8,746,275 B2
• Filed: 07/12/2011
• Issued: 06/10/2014
• Est. Priority Date: 07/14/2008
• Status: Active Grant

• Current Assignee: Copeland Comfort Control LP (Emerson Electric Company)
• Original Assignee: Emerson Electric Company
• Inventors: Santinanavat, Mike C., Panimadai Ramaswamy, Shweta Annapurani, Broker, John F., Stark, Mark H.
• Primary Examiner(s): Fristoe, Jr., John K
• Assistant Examiner(s): JELLETT, MATTHEW WILLIAM
• Application Number:
  US13/181,205
• Publication Number:
  US 20110266473A1
• Time in Patent Office: 1,064 Days
• Field of Search: 137/487.5, 251/30.01, 251/129.08, 126/39.BA
• US Class Current: 137/487.5
• CPC Class Codes: F16K 31/165 the fluid acting on a diaphragm
• CPC Class Codes: F23N 1/002 using electronic means F23N1/04 - F23N1/10 take precedence
• CPC Class Codes: F23N 2235/14 electromagnetically operated
• CPC Class Codes: F23N 2235/16 variable flow or proportional valves
• CPC Class Codes: F23N 2235/24 Valve details
• CPC Class Codes: G05D 7/0617 specially adapted for fluid materials
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

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.

Claims

1. A gas valve unit comprising:

a solenoid coil that generates a magnetic field in response to an input signal to the solenoid coil;

a valve member that is movable in response to the magnetic field for controllably displacing a valve element relative to a valve opening to adjust a gas flow rate therethrough, where the input signal to the solenoid coil controls the extent of movement of the valve member relative to the valve opening;

a sensor that provides an output indicative of a gas pressure at an outlet of the gas valve unit;

a setting device that provides an input for selection of at least one opening flow rate profile that is a function describing desired outlet pressure over a time sequence associated with a valve opening phase for establishing combustion, the opening flow rate profile configured for use in controlling the level of gas flow for initially establishing combustion in a heating apparatus; and

a valve controller in communication with the sensor and the setting device, the valve controller being configured to control the input signal to the solenoid coil to control movement of the valve element for controlling the gas flow rate through the outlet, the valve controller being configured to control the input signal to the solenoid coil based in part on the sensor output, to control the valve element and thereby control the gas flow rate at the outlet to provide outlet pressure over time in accordance with the opening flow rate profile selected by the setting device.

2. The gas valve unit of claim 1, wherein the valve controller is configured to vary the input signal to the solenoid coil after initiation of gas flow through the gas valve unit to provide the desired outlet pressure that varies over time corresponding to the opening flow rate profile selected by the setting device.

3. The gas valve unit of claim 1, wherein the valve controller is configured to compensate for variation in pressure at an inlet of the gas valve unit to achieve the outlet pressure over time in accordance with the opening flow profile selected by the setting device.

4. The gas valve unit of claim 1, wherein the at least one opening flow rate profile selectable via the setting device includes at least one of a step-opening profile, a slow-opening profile, and a fast-opening profile.

5. The gas valve unit of claim 1, wherein the valve controller is selectively configurable such that each time the gas valve unit is opened the valve controller controls the input signal to the solenoid coil for moving the valve member to provide an initial low pressure gas flow rate, and within a short time period thereafter controls the input signal to the solenoid coil for moving the valve member to provide a higher pressure increased gas flow rate, to thereby provide a step-opening characteristic.

6. The gas valve unit of claim 1, wherein the valve controller is selectively configured such that each time the gas valve unit is opened the valve controller controls the input signal to the solenoid coil for gradually moving the valve member from a minimum gas flow rate position to a full-capacity gas flow rate over a minimum time period of at least three seconds, to thereby provide a slow-opening characteristic.

7. The gas valve unit of claim 1, wherein the valve controller is selectively configured such that each time the gas valve unit is opened the valve controller controls the input signal to the solenoid coil for moving the valve member to provide a full-capacity gas flow rate in less than a three second time interval, to thereby provide a fast-opening characteristic.

8. The gas valve unit of claim 1, further comprising a look-up table associated with the valve controller that includes a set of opening flow rate profile configurations and corresponding set of values associated with each opening flow rate profile, which provide for establishing a desired outlet pressure as a function of time, wherein the valve controller is configured to select a set of values from the look up table that corresponds to a select opening flow rate profile.

9. The gas valve unit of claim 8, wherein the setting device enables selection from the set of opening flow rate configurations in the look-up table and corresponding set of values associated with each opening flow rate profile, wherein the valve controller is configured to select a set of values from the look up table that corresponds to the selection provided by the setting device.

10. The gas valve unit of claim 1, wherein the setting device comprises one of a linear dip switch or a rotary dip switch.

11. The gas valve unit of claim 1, further comprising a memory for storing data related to opening flow rates established in one or more prior valve openings, wherein the valve controller is configured to implement a learning routine that selects an optimum opening flow rate from the one or more opening flow rates, the selecting based in part on comparing rates of change of output of the sensor with rates of change of the desired outlet pressure, which data is utilized by the valve controller in subsequent control of the input signal to the solenoid coil to achieve the optimum opening flow rate profile.

12. The gas valve unit of claim 1, further comprising a pressure sensor diaphragm for providing a control signal for controlling operation of the solenoid coil to adjust the gas flow rate through the gas valve unit, without a direct mechanical linkage between a regulator diaphragm and the valve member.