34 results about "Partial stroke testing" patented technology

A partial stroke testing system for online testing of emergency shut-off valve, said system is designed for implementation on an emergency shut-off valve with a main solenoid with manual reset, main solenoid valve, quick exhaust valve and a pneumatic actuator connected to a source of pressurized air supply for opening and closing the said emergency shut-off valve and the said shut-off valve normally movable between a fully open and fully closed position. The system also include control means programmed into the plant emergency shutdown system controller for initiating electrical signal for initiating a test and for enhancing the bleed rate from the said pneumatic actuator in the event of a emergency trip signal. Test means for testing the said emergency shut-off valve without fully closing the emergency shut-off valve in response to signal from the said control means is included in the system. The said test means, controlled by the said control means, include a second solenoid and a second solenoid valve for bleeding off pressurized air to thereby move the said emergency shut-off valve from full opened position to partially closed position. Means for limiting the movement of said emergency shut-off valve to a partially closed position because of the bleeding of pressurized air is included in the system. The system also includes an isolation valve for isolating the said test means for maintenance purpose.

The invention discloses a valve stroke testing system which is characterized in that the system comprises a tested valve, a valve rod stroke control mechanism, an air intake and exhaust control device and a detecting unit; the tested valve comprises a pneumatic actuating mechanism and a sensor unit, wherein the pneumatic actuating mechanism controls the air intake or air exhaust through a two-position three-way electromagnetic valve; the sensor unit is used for obtaining the related information of a valve rod; the valve rod stroke control mechanism is provided with a limit sleeve; the valve rod is provided with a limit stop which is used for limiting a part of stroke of the valve rod; the air intake and exhaust control device is communicated with a circumscribed instrument air tank through an air intake electromagnetic valve according to one way of a buffer tank; the other way of the air intake electromagnetic valve is communicated with an air exhaust electromagnetic valve; one way of the air intake electromagnetic valve is communicated with the two-position three-way electromagnetic valve through a manual valve; and the detecting unit is used for collecting detecting signals and providing control signals of the two-position three-way electromagnetic valve, the air exhaust electromagnetic valve and the air intake electromagnetic valve. the valve stroke testing system provided by the invention can be used for online or off-line test of the valve stroke, can be used for full stroke or partial stroke test for the valve, and can be applied to pneumatic-type interlocked valves without mounting intelligent positioning devices in all industries.

A system for on-line testing of an emergency shut-off valve includes a first emergency shut-off valve and a control for initiating a test on the first emergency shut-off valve. The system also includes a fluid actuator for opening and closing the first emergency shut-off valve. A subsystem is also provided for testing the first emergency shut-off valve without fully closing the shut-off valve in response to a signal from the control. In this system, a second solenoid valve bleeds off pressurized fluid to move the emergency shut-off valve from a fully opened to a partially closed position functions as a second emergency shut-off valve. A second emergency shut-off valve is also provided in series with the first emergency shut-off valve and a bypass around the second emergency shut-off valve allows the second emergency shut-off valve to be tested by being fully closed without shutting down the process. The use of the two emergency shut-off valves in series wherein either valve can shut down the process raises the safety integrity level to level 3.

An actuating device for an on/off valve having a pneumatic drive that is connected to a compressed air supply by a solenoid valve, wherein when driven with a control voltage, the solenoid valve ventilates the pneumatic drive with the compressed air and, when the control voltage is not present, vents the pneumatic drive. The pneumatic drive moves the on/off valve into an operating position during ventilation and moves it into a safety position during venting. To permit the performance of partial-stroke tests in the simplest way possible, a device for performing the partial-stroke test includes a controllable switch which is closed in a quiescent state, and in this case supplies the control voltage to the solenoid valve. The controllable switch is opened by a control signal that is generated to perform the partial-stroke test. The control signal is supplied to the controllable switch by a position switch that is closed in the operating position of the on/off valve and is opened when the on/off valve reaches a predefined position in the direction of the safety position.

A modular actuator assembly which can be used for partial stroke testing of a valve, the assembly having a force module and a tandem piston module. The force module has a primary piston and piston rod interconnected to a shaft which is movably mounted therein. The tandem piston module is connected to the force module and has a tandem piston and piston rod. An indicator plate is connected to the piston rod and is selectively positionable on the tandem piston rod. The tandem piston rod extends into the force module and acts as a pneumatically engaged hard stop for preventing spurious travel of the primary piston and hence spurious valve travel.

The disclosure relates to a method for testing the functionality of armatures, e.g., of safety armatures, in process control systems which are assigned a test device for implementing partial stroke testing and which are connected to a control device, which brings about actuation, in accordance with regulations, of the safety armature in an emergency. Prior to the start of the implementation of the partial stroke testing, a request signal is transmitted from the test device to the control device which is answered by the control device with an enable signal, the enable signal being issued as a function of the current process sequence at the armature.

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.

Many operators choose not to utilise partial-stroke testing arrangements even when the equipment required for it to be performed is available, due to a perceived risk of over-travel and/or spurious trip. To alleviate this, we describe a safety valve system comprising a valve operable to move between an operating state and a safe state, a valve actuator operatively connected to the valve to control its state, and including a bias toward the safe state, a pair of drive members powered by a pressure media, each acting against the bias to urge the valve toward the operating state, a first control valve arranged to selectively convey pressure media to both drive members and to withdraw supply on receipt of a safety trigger, and a second control valve arranged to selectively convey pressure media to one drive member only of the pair and to withdraw supply on receipt of a test signal. In this way, a partial stroke test is possible via the second control valve, but the other drive member of the pair will remain active thus acting as a buffer that prevents excessive movement of the valve.

An emergency shut-off valve and means for initiating a test on said emergency shut-off valve includes a source of pressurized gas, a main solenoid responsive to a signal from said means for initiating a test and a source of pressurized gas are included. Further, means including a main solenoid responsive to a signal from said means for initiating a test and a main solenoid valve and a quick exhaust valve connected to the source of pressurized gas. Further, a pneumatic actuator for opening and closing the shut-off valve and test means for testing the emergency shut-off valve without fully closing the emergency shut-off valve in response to a signal from the means for initiating a test. The test means includes a second solenoid.

A safety instrument system comprises a positioner for controlling the degree of opening of an emergency cutoff valve that is provided in a pipe in a plant, and a higher-level system for controlling the PSTs (partial stroke tests) of the emergency cutoff valve. The positioner has: a portion for executing a PST on the emergency cutoff valve in response to an initiating instruction from the higher-level system or to an initiating instruction from an operating panel on the plant floor wherein the positioner is provided; a timer for measuring elapsed time from the completion of a PST on the emergency cutoff valve; and a portion for evaluating whether or not a PST is permitted, by comparing elapsed time from the previous PST, to a PST minimum interval that is set in advance.

A manual and pneumatic integrated valve comprises a pressing plate, a first sealing gasket, a valve body, a limiting base, a first polyurethane seal ring, an O-ring, a shaft sleeve, a first valve element, a pressing cap, a second sealing gasket, a second polyurethane seal ring, a first upper cover, a button support, a key valve button, a second upper cover and a second valve element. The limitingbase and the first polyurethane seal ring are arranged on the valve body. The O-ring is arranged on the shaft sleeve and used for sealing between the shaft sleeve and the valve body. The valve elementis arranged in the shaft sleeve. A slide valve sealing mode is adopted between the valve element and the shaft sleeve. The pressing cap is arranged at the upper portion of the valve element. The second polyurethane seal ring is arranged in the first upper cover. The button support is arranged on the first upper cover. The second sealing gasket and the first upper cover are assembled together andarranged in the valve body. The key valve button is arranged on the second upper cover. The second upper cover is arranged on the valve body. The manual and pneumatic integrated valve has functions ofa key valve, also has functions of a two-position three-way double-air-control valve and can make a PST partial stroke test loop simpler and more reliable.

The invention discloses an online detection method for external characteristics of an in-service pneumatic stop valve based on pulse excitation, and belongs to the field of functional safety detection and evaluation. According to the invention, an external characteristic detection method based on pulse excitation is used for carrying out external characteristic online detection on the in-service pneumatic stop valve, a control system sends current pulse excitation to an electromagnetic valve of the pneumatic stop valve so as to enable the electromagnetic valve to be repeatedly powered on and powered off, a valve rod of an executing mechanism is driven to repeatedly rotate by a small amplitude, the rotation angle of the valve is regulated and controlled by adjusting the duration time of the low-level pulse width within the allowable range of equipment, the output characteristic of the maximum angular displacement is detected, and online detection of the external characteristics of the in-service pneumatic stop valve is achieved. The problem of external characteristic online detection of the in-service pneumatic stop valve without a partial stroke test function is solved, the situation that normal production is affected by too large rotation amplitude of the valve rod in the detection process is avoided, and a basis is provided for evaluating the functional safety integrity of the pneumatic stop valve of a safety instrument system in a safety life cycle.

A method for verifying the operation of a safety valve(310) having a valve member and a positioner(340) for controlling the position of the valve member is proposed. The safety valve (310) is part of a plant on which a process with a process medium runs. The plant has a sensor (350)for monitoring the state of the plant, the procdess and the process medium. A sensor(350)'s measured value is used to determine a point in time during ongoing plant operation at which the operability of the valve (310) can be verified in the context of a partial stroke test. The test can also be monitored with the sensor(350) and the stroke range traversed therein can be dynamically adapted to the state. The test can thus be performed safely during operation and with an optimized stroke range. The method enables more frequent testing of and more reliable statements about the operability of the safety valve(310).

The invention provides a partial stroke testing method for a gas safety diffuse water seal valve for a coke oven gas collector. The partial stroke testing method comprises the following steps: arranging a plurality of pressure sensors in the coke oven gas collector and calculating maximal pressure P' according to a plurality of pressure measuring points P_1, P_2 until P_N; calculating the minimumwater seal liquid level height H0 at the position of no gas leakage according to maximum pressure P'; calculating a maximum rotation angle alpha in the stroke test according to the minimum water sealliquid level height H0, the actual length L of a valve plate, a dip angle beta of a baffle and normal water seal height Hmax. According to the partial stroke testing method disclosed by the invention,stroke test of the diffuse water seal valve can be performed at fixed period, and the phenomena of corrosion or blockage caused by long-time inaction of the valve can be prevented; when the pressureof the gas collector pressure is overhigh, the diffuse valve can be opened in time; in the stroke testing process of the valve, the opening degree of the valve is increased as much as possible while no gas breaks through a water seal cover and the testing adequacy is ensured.