Adjustable deadband control system

Patent metadata

Field	Value
Publication number	US-10678274-B2
Application number	US-201715673053-A
Country	US
Kind code	B2
Filing date	Aug 9, 2017
Priority date	Jun 3, 2015
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

Control systems include various combinations of pressure regulators, pilots, and pressure stabilizers to provide systems with adjustable deadbands for over pressure protection, adjustable deadbands for under pressure protection, adjustable deadbands for both over pressure and under pressure protection, pressure assisted closure for over pressure protection, pressure assisted closure for under pressure protection, pressure assisted closure for both over pressure and under pressure protection, or spring assisted closure for over pressure and under pressure protection.

First claim

What is claimed is:

1. A control system, comprising:
a 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, the diaphragm assembly dividing the cavity into a first chamber and a second chamber, wherein the first chamber of the actuator assembly is in direct fluid communication with the fluid outlet;
a first pilot in direct fluid communication with the first and second chambers of the actuator assembly and the fluid outlet;
a second pilot in direct fluid communication with the first pilot and the fluid outlet; and
a pressure stabilizer in direct fluid communication with the fluid inlet, the fluid outlet, and the second pilot.

2. The control system of claim 1 , wherein:
the first pilot is in an open position and the second pilot is in a closed position with a pressure of a process fluid at the fluid outlet below a first setpoint of the first pilot and below a second setpoint of the second pilot;
the first pilot is in the open position and the second pilot is in an open position with the pressure of the process fluid at the outlet above the second setpoint and below the first setpoint; and
the first pilot is in a closed position and the second pilot is in the open position with the pressure of the process fluid at the fluid outlet above the first setpoint and above the second setpoint.

3. The control system of claim 1 , wherein:
the first pilot comprises a cavity, a first diaphragm assembly disposed within the cavity, and a second diaphragm assembly disposed within the cavity, the first and second diaphragm assemblies dividing the cavity into a first chamber, a second chamber, and a third chamber;
the actuator assembly is in direct fluid communication with the second chamber of the first pilot;
the second pilot is in direct fluid communication with the second chamber of the first pilot with a plug of the first pilot spaced apart from a seat of the first pilot; and
the third chamber of the first pilot is in direct fluid communication with the fluid outlet.

4. The control system of claim 1 , wherein:
the second pilot comprises a cavity, a first diaphragm assembly disposed within the cavity, and a second diaphragm assembly disposed within the cavity, the first and second diaphragm assemblies dividing the cavity into a first chamber, a second chamber, and a third chamber;
the first pilot is in direct fluid communication with the second chamber of the second pilot;
the pressure stabilizer is in direct fluid communication with the second chamber of the second pilot with a plug of the second pilot spaced apart from a seat of the second pilot; and
the third chamber of the second pilot is in direct fluid communication with the fluid outlet.

5. The control system of claim 1 , wherein:
the pressure stabilizer comprises a cavity and a diaphragm assembly disposed within the cavity, the diaphragm assembly dividing the cavity into a first chamber and a second chamber;
the second pilot is in direct fluid communication with the second chamber of the pressure stabilizer;
the first chamber of the pressure stabilizer is in direct fluid communication with the fluid outlet; and
the second chamber of the pressure stabilizer is in direct fluid communication with the fluid inlet when a plug of the pressure stabilizer is spaced apart from a seat of the pressure stabilizer.

6. A control system, comprising:
a pressure regulator, comprising:
a valve plug that is movable between an open position that permits fluid flow through the pressure regulator and a closed position that prevents fluid flow through the pressure regulator; and
an actuator assembly that is responsive to a supply pressure and a downstream pressure to modulate the valve plug between the open position and the closed position, the actuator assembly comprising a cavity and a diaphragm assembly disposed in the cavity, the diaphragm assembly dividing the cavity into a first chamber and a second chamber, wherein the first chamber is in fluid communication with a fluid outlet of the pressure regulator;

an under-pressure pilot device; and
an over-pressure pilot device in direct fluid communication with the first and second chambers of the actuator assembly and the fluid outlet of the pressure regulator,
wherein the under-pressure pilot device and the over-pressure pilot device are connected in series and configured to route the supply pressure to the actuator assembly when the downstream pressure is within a pressure range and to isolate the supply pressure from the actuator assembly when the downstream pressure is not within the pressure range.

7. The control system of claim 6 , wherein the under-pressure pilot device is in fluid communication with the over-pressure pilot device and the fluid outlet of the pressure regulator.

8. The control system of claim 6 , comprising a pressure stabilizer in fluid communication with the under-pressure pilot device and with a fluid inlet and the fluid outlet of the pressure regulator.

9. The control system of claim 6 , wherein the over-pressure pilot device is set at a first setpoint and the under-pressure pilot device is set at a second setpoint, lower than the first setpoint.

10. The control system of claim 9 , wherein:
the over-pressure pilot device is in an open position and the under-pressure pilot device is in a closed position with the downstream pressure below the first setpoint and below the second setpoint;
the over-pressure pilot device is in the open position and the under-pressure pilot device is in an open position with the downstream pressure above the second setpoint and below the first setpoint; and
the over-pressure pilot device is in a closed position and the under-pressure pilot device is in the open position with the downstream pressure above the first setpoint and above the second setpoint.

11. A control system, comprising:
a first pilot having a first inlet and a first outlet, wherein the first pilot is configured to couple the first inlet to the first outlet when a control pressure is below a first setpoint;
a second pilot having a second inlet and a second outlet, wherein the second pilot is configured to couple the second inlet to the second outlet when the control pressure is above a second setpoint; and
a pressure regulator, comprising:
a valve plug that is movable between an open position that permits fluid flow through the pressure regulator and a closed position that prevents fluid flow through the pressure regulator; and
an actuator assembly that is configured to modulate the valve plug between the open and closed positions to maintain the control pressure at a pressure setpoint, the actuator assembly comprising a cavity and a diaphragm assembly disposed in the cavity, the diaphragm assembly dividing the cavity into a first chamber and a second chamber, wherein the first chamber is in fluid communication with a fluid outlet of the pressure regulator;
wherein the first pilot is in direct fluid communication with the first and second chambers of the actuator assembly and the fluid outlet of the pressure regulator, and wherein the first pilot and the second pilot are connected in series to route a supply pressure to the actuator assembly when the control pressure is between the first setpoint and the second setpoint and to isolate the supply pressure from the actuator assembly when the control pressure is not between the first setpoint and the second setpoint.

12. The control system of claim 11 , wherein the first pilot is configured to prevent fluid flow from the first inlet to the first outlet when the control p

Assignees

• Emerson Process Man Regulator Technologies Inc

Inventors

• Masias Justin Lane
• Scheffler Douglas James
• Nguyen Tung K
• Bagby James Curtis

Classifications

• F16K17/02

  opening on surplus pressure on one side; closing on insufficient pressure on one side (check valves F16K15/00) · CPC title

• F16K17/10

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

• G05D16/16

  derived from the controlled fluid · CPC title

• F16K31/126

  the fluid acting on a diaphragm, bellows, or the like (F16K31/145, F16K31/165, F16K31/365, F16K31/385 take precedence) · CPC title

• G05D16/163 Primary

  using membranes within the main valve · CPC title