DEVICE AND METHOD FOR QUANTIFYING A LEAKAGE FLOW ON AN ACTUATOR

• US 20140047902A1
• Filed: 08/15/2013
• Published: 02/20/2014
• Est. Priority Date: 08/16/2012
• Status: Active Grant

• Current Assignee: Samson AG
• Original Assignee: Samson AG
• Inventors: Kiesbauer, Joerg
• Granted Patent: US 9,528,901 B2
• Time in Patent Office: Days
• US Class Current: 73/40.5A
• 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 leakage flow on a process control valve that restricts a process stream, comprising the steps of:

using an intact 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 the respective reference flow value, allocating a reference mechanical vibration acquired in an environment of the reference control valve to the respective reference flow value;

determining an instantaneous mechanical vibration on the process control valve when it is closed;

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

equating the leakage flow to be quantified with the reference flow value allocated to the identified reference mechanical vibration.

2. 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 instantaneous mechanical vibration.

3. The method according to claim 1 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.

4. The method according to claim 2 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.

5. 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.

6. 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.

7. 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.

8. 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.

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

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

a data memory that stores several reference flow values determined using an intact reference control valve by moving the reference control valve into several reference opening positions and measuring the respective reference flow value for each reference opening position, and a reference mechanical vibration measured for each of the reference opening positions in an environment of the reference control valve being allocated to the respective reference flow value;

a mechanical vibration sensor for measuring instantaneous mechanical vibration on the closed process control valve; and

data processing electronics which, based upon an identity comparison or approximation comparison, identifies the reference mechanical vibration coming closest to the instantaneous mechanical vibration and equates the leakage flow to be quantified with the reference flow value allocated to the identified reference mechanical vibration.

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