Device and method for quantifying a leakage flow on an actuator

• US 9,528,901 B2
• Filed: 08/15/2013
• Issued: 12/27/2016
• Est. Priority Date: 08/16/2012
• Status: Active Grant

• Current Assignee: Samson AG
• Original Assignee: Samson AG
• Inventors: Kiesbauer, Joerg
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Kidanu, Gedeon M
• Application Number:
  US13/967,663
• Publication Number:
  US 20140047902A1
• Time in Patent Office: 1,230 Days
• Field of Search: 73/40, 73/47, 731/68, 735/92, 736/59, 340/605, 340/621, 137/551, 702/51
• US Class Current: 1/1
• CPC Class Codes: F16K 37/0075 For recording or indicating the functioning of a valve in combination with test equipment
• CPC Class Codes: G01M 3/02 by using fluid or vacuum
• CPC Class Codes: G01M 3/24 using infrasonic, sonic, or ultrasonic vibrations
• CPC Class Codes: G01M 3/2876 for valves G01M3/30 takes precedence

Abstract

In a method or device for quantifying a leakage flow on a process control valve, an intact reference control valve is used to determine several reference flow values in advance by placing the reference control valve in several reference opening positions and measuring the respective reference flow value for each of the reference opening positions. When determining the respective reference flow value, a reference mechanical vibration acquired in an environment of the reference control valve is allocated to the respective reference flow value. An instantaneous mechanical vibration is determined on the process control valve when it is closed. The reference mechanical vibration coming closest to the determined instantaneous mechanical vibration is identified by an identity or approximation comparison. The leakage flow is equated with the reference flow value allocated to the identified reference mechanical vibration.

Claims

1. A method for quantifying a wear-induced leakage flow on a closed process control valve that restricts a process stream, comprising the steps of:

using said process control valve when it is intact and does not yet have a wear-induced leakage as a reference control valve or another process control valve of a same design as said process control valve which does not have wear-induced leakage as said reference control valve to determine several reference flow values in advance by placing the reference control valve in several reference opening positions, and measuring the respective reference flow value for each of the reference opening positions;

when determining each of the respective reference flow values, allocating a respective reference mechanical vibration acquired in an environment of the reference control valve to each of the respective reference flow values;

determining an instantaneous mechanical vibration caused by said wear-induced leakage flow on said closed process control;

determining an instantaneous stream force prevailing on said process control valve;

identifying one of the respective reference mechanical vibrations coming closest to the determined instantaneous mechanical vibration by way of an identity comparison or approximation comparison;

defining said identity comparison or approximation based on the determined instantaneous stream force; and

equating the wear-induced leakage flow to be quantified with the respective reference flow value allocated to the one identified reference mechanical vibration.

2. The method according to claim 1 in which the reference opening positions are selected such that their passage cross sections correspond to typical leakage passage cross sections based on wear history data of control valves corresponding to a design of the process control valve.

3. The method according to claim 1 in which a sound level/opening position characteristic is generated for the intact reference control valve, so as to allocate each determined instantaneous mechanical vibration by way of the characteristic to the reference opening position, said reference opening position being output as a leakage opening of the process control valve.

4. The method according to claim 1 in which the instantaneous mechanical vibration is monitored, and a warning signal is output when a permissible reference mechanical vibration value prescribed in advance has been exceeded.

5. The method according to claim 1 in which a progression of the instantaneous mechanical vibration is acquired while opening the process control valve and compared to a reference progression of the reference mechanical vibration while opening the intact reference control valve.

6. The method of claim 1 in which the process fluid stream has a substantially constant stream pressure.

7. The method according to claim 1 in which a reference process fluid stream pressure prevailing on the reference control valve is acquired in advance, and a reference flow value is determined from it, and wherein the reference process fluid stream pressure is also compared with an instantaneous process fluid stream pressure determined on the process control valve so as to identify the closest respective reference mechanical vibration.

8. The method according to claim 7 in which the instantaneous stream pressure prevailing on the process control valve is determined via a pneumatic driving pressure to be applied for keeping the process control valve in its closed position.

9. The method according to claim 7 in which the instantaneous stream pressure prevailing directly on the process valve or an instantaneous flow just before the process control valve closes is determined and stored, and the reference mechanical vibration to be allocated for the leakage flow to be quantified is detected taking into account the instantaneous stream pressure prior to the closing process.

10. A device for quantifying an instantaneous leakage flow on a closed process control valve that restricts a process fluid stream, comprising:

a data memory that stores;

several reference flow values determined by using said process control valve when it is intact and does not yet have a wear-induced leakage as a reference control valve or another process control valve of a same design as said process control valve which does not have wear-induced leakage as said reference control valve to determine said several reference flow values in advance by placing the reference control valve in several reference opening positions, and measuring the respective reference flow value for each of the reference opening positions; and

several sets of sound-level/opening-position value pairs generated based on respectively process fluid stream forces prevailing on the process control valve;

a pressure sensor configured to determine a pneumatic driving pressure of a pneumatic actuating drive of the process control valve, and determine an instantaneous process fluid stream force prevailing on the process control valve based on the determined pneumatic driving pressure, or a stream force sensor configured to measure said instantaneous process fluid stream force prevailing on the process control valve;

a mechanical vibration sensor and a data processing electronics used, when determining each of the respective reference flow values, to allocate a respective reference mechanical vibration acquired by said vibration sensor in an environment of the reference control valve to each of the respective reference flow values;

also with said mechanical vibration sensor or another mechanical vibration sensor determining an instantaneous mechanical vibration caused by said wear-induced leakage flow on said closed process control valve; and

said data processing electronics being configured to;

identify one of the respective reference mechanical vibrations coming closest to the determined instantaneous mechanical vibration by way of an identity comparison or approximation comparison in one of said several sets of sound-level/opening-position value pairs based on the instantaneous process fluid stream force prevailing on the process control valve; and

equate the wear-induced leakage flow to be quantified with the respective reference flow value allocated to the one identified reference mechanical vibration.

11. The device of claim 10 wherein the process fluid stream has a substantially constant stream pressure.

12. The device of claim 10, wherein application of the pneumatic driving pressure places and keeps the process control valve in its closed position.