Adjustable deadband control system

Patent metadata

Field	Value
Publication number	US-11733722-B2
Application number	US-202117481828-A
Country	US
Kind code	B2
Filing date	Sep 22, 2021
Priority date	Jun 3, 2015
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A control system having a first pressure regulator, a downstream fluid control device, first pilot, and second pilot. The first pressure regulator has a fluid inlet, fluid outlet, and actuator assembly with a cavity divided into a first chamber and a second chamber. The downstream fluid control device has a second fluid inlet and a second fluid outlet. The first pilot has a first setpoint and the second pilot has a second setpoint, less than the first setpoint. The first and second pilots fluidly couple the second chamber to the second fluid outlet in a first mode of operation, isolate the second chamber from the second fluid outlet in a second mode of operation, and fluidly couple the second chamber to the fluid inlet in a third mode of operation.

First claim

What is claimed is:

1. A control system, comprising:
a first pressure regulator comprising a fluid inlet, a fluid outlet, and an actuator assembly, the actuator assembly comprising a cavity and a diaphragm assembly disposed within the cavity and dividing the cavity into a first chamber and a second chamber;
a downstream fluid control device comprising a second fluid inlet in fluid communication with the fluid outlet of the first pressure regulator and a second fluid outlet in fluid communication with the first chamber of the first pressure regulator;
a first pilot in direct fluid communication with the second chamber of the actuator assembly and the fluid inlet, the first pilot having a first setpoint;
a second pilot in direct fluid communication with the second chamber of the actuator assembly, the fluid inlet, and the second fluid outlet, the second pilot having a second setpoint, less than the first setpoint;
wherein the first pilot and the second pilot are configured to:
fluidly couple the second chamber to the second fluid outlet with the control system in a first mode of operation;
isolate the second chamber from the second fluid outlet and the fluid inlet with the control system in a second mode of operation; and
fluidly couple the second chamber to the fluid inlet with the control system in a third mode of operation.

2. The control system of claim 1 , wherein:
the first pilot is configured to be in a closed position and the second pilot is configured to be in an open position with the control system in the first mode of operation;
the first pilot is configured to be in the closed position and the second pilot is configured to be in a closed position with the control system in the second mode of operation; and
the first pilot is configured to be in an open position and the second pilot is configured to be in the closed position with the control system in the third mode of operation.

3. The control system of claim 1 , wherein:
the control system is configured to operate in the first mode of operation with a fluid pressure at the fluid inlet below the first setpoint and below the second setpoint;
the control system is configured to operate in the second mode of operation with the fluid pressure at the fluid inlet above the second setpoint and below the first setpoint; and
the control system is configured to operate in the third mode of operation with the fluid pressure at the fluid inlet above the first setpoint and above the second setpoint.

4. The control system of claim 1 , wherein the first pressure regulator is configured to be closed when a fluid pressure at the fluid inlet transitions from a value below the second setpoint to a value between the first setpoint and the second setpoint and configured to be open when the fluid pressure at the fluid inlet transitions from a value above the first setpoint to a value between the first setpoint and the second setpoint.

5. The control system of claim 4 , where the first pressure regulator is configured to be open when there is a fluid pressure at the second fluid outlet with the fluid pressure at the fluid inlet greater than the first setpoint.

6. The control system of claim 1 , wherein:
the first pressure regulator is configured to be in a closed position with a fluid pressure at the fluid inlet below the second setpoint; and
the first pressure regulator is configured to be in an open position with the fluid pressure at the fluid inlet above the first setpoint.

7. The control system of claim 1 , wherein the first pressure regulator is a back-pressure regulator.

8. The control system of claim 7 , wherein the first pressure regulator comprises a spring disposed in the first chamber to urge the first pressure regulator towards a closed position.

9. The control system of claim 1 , wherein the first pilot comprises a first port in fluid communication with the fluid inlet of the first pressure regulator, a second port in fluid communication with the second pilot and the second chamber of the first pressure regulator, and a third port in fluid communication with the fluid inlet of the first pressure regulator and with a diaphragm assembly of the first pilot.

10. The control system of claim 9 , wherein the first pilot comprises a spring to urge the first pilot toward a closed position.

11. The control system of claim 9 , wherein the second pilot comprises a first port in fluid communication with the second port of the first pilot and the second chamber of the first pressure regulator, a second port in fluid communication with the second fluid outlet of the downstream fluid control device, and a third port in fluid communication with the fluid inlet of the first pressure regulator and with a diaphragm assembly of the second pilot.

12. The control system of claim 11 , wherein the second pilot comprises a spring to urge the second pilot toward an open position.

13. The control system of claim 1 , wherein the downstream fluid control device is a second pressure regulator that is configured to control a fluid pressure downstream of the second pressure regulator, the second pressure regulator comprising a second actuator assembly, the second actuator assembly comprising a second cavity and a second diaphragm assembly disposed within the second cavity and dividing the second cavity into a first chamber and a second chamber.

14. The control system of claim 13 , wherein the second pressure regulator is a pressure-reducing regulator.

15. The control system of claim 14 , wherein the second pressure regulator comprises a spring disposed in the first chamber of the second pressure regulator to urge the second pressure regulator towards a closed position.

16. The control system of claim 13 , comprising a third pilot having a first port in fluid communication with the second fluid outlet of the second pressure regulator and the second chamber of the cavity of the first pressure regulator, a second port in fluid communication with the second chamber of the second pressure regulator, and a third port in fluid communication with a pressure stabilizer, and a fourth port in fluid communication with the second fluid outlet of the second pressure regulator, the first chamber of the second pressure regulator, and a diaphragm assembly of the third pilot.

17. The control system of claim 16 , wherein the third pilot comprises a spring to urge the third pilot toward an open position.

18. The control system of claim 16 , wherein the pressure stabilizer comprises a first port in fluid communication with the second fluid outlet of the second pressure regulator, a second port in fluid communication with the second fluid inlet of the second pressure regulator, and a third port in fluid communication with the third port of the third pilot.

Assignees

• Emerson Process Man Regulator Technologies Inc

Inventors

• Masias Justin L

Classifications

• G05D16/163 Primary

  using membranes within the main valve · CPC title

• F16K17/10

  with auxiliary valve for fluid operation of the main valve · CPC title

• G05D16/024

  Controlling the inlet pressure, e.g. back-pressure regulator · CPC title

• G05D16/16

  derived from the controlled fluid · CPC title

• F16K1/523

  for limiting the maximum flow rate, using a stop · CPC title