# US 10,480,681 B2 · Partial stroke tests for shutdown valves > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,681 B2 - Document ID: US10480681B2 - Status: Granted - Kind: B2 - Application number: 15/387,272 - Filed: 2016-12-21 - Published: 2017-06-29 - Granted: 2019-11-19 - Earliest claimed: 2015-12-23 - Assignees: Fisher Controls International LLC - Applicants: Fisher Controls International LLC - Inventors: Kenneth W. Junk - Web page: https://patentgrep.com/patent/US10480681B2 ## CPC - F16K 37/0083: {by measuring valve parameters} - F15B 15/066: {the motor being of the scotch yoke type} - F15B 19/005: {Fault detection or monitoring} - F15B 20/00: Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems - F15B 21/087: {Control strategy, e.g. with block diagram} - F16K 31/1221: {one side of the piston being spring-loaded} - F16K 31/1635: {for rotating valves} - F15B 2211/6313: the pressure being a load pressure - F15B 2211/6336: representing a state of the output member, e.g. position, speed or acceleration - F15B 2211/6656: Closed loop control, i.e. control using feedback - F15B 2211/7052: Single-acting output members - F15B 2211/755: Control of acceleration or deceleration of the output member - F15B 2211/8752: Emergency operation mode, e.g. fail-safe operation mode - F15B 2211/8755: Emergency shut-down - F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)} - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval. ## Claims ### Claim 1 A method for executing partial-stroke tests of valves, the method comprising: generating a setpoint signal to stroke a valve during a partial-stroke test, including: determining a first target for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test, wherein the first target corresponds to a larger extent of valve travel than the travel displacement threshold, ramping the setpoint signal from an initial value to the first target, during a first time interval, subsequently to the first time interval, maintaining the setpoint signal at the first target during a second time interval, determining a second target for the setpoint signal based at least on the initial value, and during a third time interval subsequent to the second interval, ramping the setpoint signal from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval; applying the setpoint signal to the valve; and determining whether the valve passes the partial-stroke test using a response to the setpoint signal. ### Claim 2 (depends on 1) The method of claim 1, wherein generating the setpoint signal includes maintaining the setpoint signal at the first target during the second time interval for a predetermined fixed amount of time. ### Claim 3 (depends on 1) The method of claim 1, wherein determining whether the valve passes the partial-stroke test includes: receiving an indication of current valve position during execution of the partial-stroke test, and comparing the current valve position to an acceptance criterion, wherein the acceptance criterion corresponds to the desired extent of travel of the valve. ### Claim 4 (depends on 3) The method of claim 3, wherein generating the setpoint signal further includes: transitioning from the second interval to the third time interval in response to determining that the current valve position reached the travel displacement threshold. ### Claim 5 (depends on 4) The method of claim 4, wherein transitioning from the second interval to the third time interval includes modifying the setpoint by a predetermined factor prior to ramping the setpoint signal during the third interval. ### Claim 6 (depends on 5) The method of claim 5, wherein modifying the setpoint by the predetermined factor includes: adding the predetermined factor to a current value of the setpoint signal if the current valve position lags behind the setpoint signal, or adding the predetermined factor to a current value of the of current valve position if the current valve position leads the setpoint signal. ### Claim 7 (depends on 3) The method of claim 3, further comprising: comparing the current valve position to an abort criterion that corresponds to a maximum allowable extent of travel of the valve; and in response to determining that the current valve position exceeds the abort criterion, aborting the partial-stroke test. ### Claim 8 (depends on 1) The method of claim 1, wherein determining the first target for the setpoint signal includes applying a predetermined factor to the travel displacement threshold. ### Claim 9 (depends on 1) The method of claim 1, wherein: the initial value and the first target differ by a first amount, the first target and the second target differ by a second amount, and the method includes determining the second target for the setpoint signal so that the second amount is larger than the first amount, to thereby overdrive the setpoint signal during the third interval. ### Claim 10 (depends on 1) The method of claim 1, wherein generating the setpoint signal to stroke a valve during a partial-stroke test further includes cutting off the setpoint signal after the setpoint signal reaches the second target. ### Claim 11 (depends on 1) The method of claim 1, further comprising receiving, via an operator interface, a selection of the desired extent of travel of the valve during the partial-stroke test. ### Claim 12 (depends on 1) The method of claim 1, further comprising: receiving, via an operator interface, an indication of a rate of change for the setpoint signal; wherein ramping the setpoint signal includes ramping the setpoint signal at the indicated rate. ### Claim 13 (depends on 1) The method of claim 1, further comprising: receiving, via an operator interface, an indication of a first rate of change for the setpoint signal and a second rate of change for the setpoint signal different from the first indicated rate, wherein: ramping the setpoint signal during the first time interval includes ramping the setpoint signal at the first indicated rate, and ramping the setpoint signal during the third time interval includes ramping the setpoint signal at the second indicated rate.