STEPPER MOTOR VALVE AND METHOD OF CONTROL

• US 20100009303A1
• Filed: 07/14/2008
• Published: 01/14/2010
• 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., Jensen, Ryan D., Atri, Jagdish C., Butler, William P.
• Granted Patent: US 8,381,760 B2
• Time in Patent Office: Days
• US Class Current: 431/12
• CPC Class Codes: F16K 31/128 servo actuated
• CPC Class Codes: F16K 31/402 acting on a diaphragm
• CPC Class Codes: F16K 31/42 by means of electrically-actuated members in the supply or discharge conduits of the fluid motor F16K31/40 takes precedence
• CPC Class Codes: F23N 1/002 using electronic means F23N1/04 - F23N1/10 take precedence
• CPC Class Codes: G05D 16/202 actuated by an electric motor
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/7764 Choked or throttled pressure type

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 stepper-motor regulated gas valve control, comprising:

a main diaphragm chamber,

a main diaphragm in the main diaphragm chamber that controllably displaces a valve relative to a valve opening in response to changes in pressure in the main diaphragm chamber, to thereby permit adjustment of the flow of fuel through the valve opening;

a servo-regulator diaphragm configured to regulate fluid flow to the main diaphragm chamber, to control the rate of fuel flow through the valve opening;

a stepper motor configured to move in a stepwise manner to displace the servo-regulator diaphragm for regulating fluid flow to the diaphragm chamber, to thereby regulate the rate of fuel flow through the valve opening; and

a control circuit configured to receive an input control signal from which a reference value of between 0 and 5 volts is obtained, said control circuit being configured to determine a select motor step value that corresponds to the obtained reference value, and to move the stepper-motor to the selected motor step value for displacing the servo-regulator diaphragm, to thereby regulate the rate of fuel flow through the valve opening.

2. The stepper-motor regulated gas valve control of claim 1, wherein the input control signal is a milli-volt signal in the range of from 0 to 180 milli-volt, and the control circuit is configured to convert the received signal from a value of between 0 and 180 millivolts to a corresponding reference value of between 0 and 5 volts.

3. The stepper-motor regulated gas valve control of claim 1, further comprising a look-up table associated with the control circuit, which includes a set of motor step values that correspond to a number of reference values that are in the range of between 0 and 5 volts, wherein the control circuit is configured to determine a motor step amount by selecting a motor step value from the look up table that corresponds to the reference value obtained from the input control signal.

4. The stepper-motor regulated gas valve control of claim 1, wherein the set of motor step values correspond to a plurality of positions of the stepper motor for adjusting the regulator, said plurality of positions ranging from a closed no-flow position to a full capacity position.

5. The stepper-motor regulated gas valve control of claim 1, wherein said control circuit is disposed on the stepper-motor regulated gas valve.

6. The stepper-motor regulated gas valve control of claim 1, further comprising a burner that is supplied with fuel by the stepper-motor regulated gas valve control, and a system controller that employs the control circuit for controlling the operation of the stepper-motor regulated gas valve control.

7. The stepper-motor regulated gas valve control of claim 6, wherein the system controller is selectively configurable to control the movement of the stepper motor to provide an opening characteristic that is a function of the valve'"'"'s outlet pressure over time.

8. The stepper-motor regulated gas valve control of claim 7, wherein the system controller is selectively configured such that each time the stepper-motor regulated gas valve is opened the system controller incrementally moves the stepper-motor to provide an initial low pressure supply of fuel and within a short interval thereafter move the stepper motor to provide an increased higher pressure supply of fuel, to thereby provide a step-opening characteristic.

9. The stepper-motor regulated gas valve control of claim 7, wherein the system controller is selectively configured such that each time the stepper-motor regulated gas valve is opened the system controller gradually moves the stepper-motor from a closed no-flow position to a full-capacity supply of fuel flow over a minimum time interval of at least three seconds, to thereby provide a slow-opening characteristic.

10. The stepper-motor regulated gas valve control of claim 7, wherein the system controller is selectively configured such that each time the stepper-motor regulated gas valve is opened the system controller moves the stepper-motor from a closed no-flow position to a full-capacity supply of fuel flow in less than a three second time interval, to thereby provide a fast-opening characteristic.

11. The stepper-motor regulated gas valve control of claim 7, where the system controller is selectively configurable by a dip switch having a setting for a step-opening characteristic, a slow-opening characteristic, and a fast-opening characteristic.

12. A stepper-motor regulated gas valve control adaptable for a number of different fuel-fired furnace designs, the stepper-motor regulated gas valve control comprising:

a main diaphragm chamber,

a main diaphragm in the main diaphragm chamber that controllably displaces a valve relative to a valve opening in response to changes in pressure in the main diaphragm chamber, to thereby permit adjustment of the flow of fuel through the valve opening;

a servo-regulator diaphragm configured to regulate fluid flow to the main diaphragm chamber to thereby control the rate of fuel flow through the valve;

a stepper motor configured to move in a stepwise manner to displace the servo-regulator diaphragm for regulating fluid flow to the diaphragm chamber, to thereby regulate the rate of fuel flow through the valve opening; and

a controller mounted on the stepper-motor regulated gas valve control that receives an input control signal ranging from 0 to 180 millivolts, and to convert a signal value of between 0 and 180 millivolts to a proportionally corresponding reference value of between 0 and 5 volts, said controller including a look-up table with a set of motor step values that correspond to a number of reference values between 0 and 5 volts, wherein the control circuit is configured to select a motor step value from the look up table that corresponds to the reference value obtained from the input control signal, and to move the stepper-motor in a step wise manner to the selected motor step value, to displace the servo-regulator diaphragm and thereby regulate the rate of fuel flow through the valve opening.

13. The stepper-motor regulated gas valve control of claim 12, wherein the set of motor step values correspond to a plurality of positions of the stepper motor for adjusting the regulator, said plurality of positions ranging from a closed no-flow position to a full capacity position.

14. The stepper-motor regulated gas valve control of claim 12, wherein said control circuit is disposed on the stepper-motor regulated gas valve.

15. The stepper motor regulated gas valve control of claim 12 further comprising a burner that is supplied with fuel by the stepper-motor regulated gas valve control, and a system controller that communicates with the controller for controlling the operation of the stepper-motor regulated gas valve control.

16. The stepper-motor regulated gas valve control of claim 15, where the system controller is selectively configurable by a dip switch having a setting for communicating to the controller to provide one of a step-opening characteristic, a slow-opening characteristic, and a fast-opening characteristic.

17. A fuel-fired heating system comprising a controller for controlling the rate of fuel flow to a burner, the fuel-fired system comprising:

a burner for receiving the supply of fuel flow for combustion in a fuel-fired heating apparatus;

a stepper motor regulated gas valve control for supplying fuel flow to the burner;

the stepper-motor regulated gas valve control including;

a main diaphragm chamber,

a main diaphragm in the main diaphragm chamber that controllably displaces a valve relative to a valve opening in response to changes in pressure in the main diaphragm chamber, to thereby permit adjustment of the flow of fuel through the valve opening;

a servo-regulator diaphragm configured to regulate fluid flow to the main diaphragm chamber to thereby control the rate of fuel flow through the valve opening;

a stepper motor configured to move in a stepwise manner to displace the servo-regulator diaphragm for regulating fluid flow to the diaphragm chamber, to thereby regulate the rate of fuel flow through the valve opening; and

a system controller for controlling the operation of the stepper-motor regulated gas valve control to controllably initiate and discontinue the flow of fuel to the burner, the system controller being selectively configurable to control the movement of the stepper motor to provide an opening characteristic that is a function of the valve'"'"'s outlet pressure over time.

18. The stepper-motor regulated gas valve control of claim 17, wherein the system controller is selectively configured such that each time the stepper-motor regulated gas valve is opened the system controller incrementally moves the stepper-motor to provide an initial low pressure supply of fuel and within a short interval thereafter move the stepper motor to provide an increased higher pressure supply of fuel, to thereby provide a step-opening characteristic.

19. The stepper-motor regulated gas valve control of claim 17, wherein the system controller is selectively configured such that each time the stepper-motor regulated gas valve is opened the system controller gradually moves the stepper-motor from a closed no-flow position to a full-capacity supply of fuel flow over a minimum time interval of at least three seconds, to thereby provide a slow-opening characteristic.

20. The stepper-motor regulated gas valve control of claim 17, wherein the system controller is selectively configured such that each time the stepper-motor regulated gas valve is opened the system controller moves the stepper-motor from a closed no-flow position to a full-capacity supply of fuel flow in less than a three second time interval, to thereby provide a fast-opening characteristic.