Actuator controls 5.1 Force/ torque sensing 5.2 Position-sensing 5.3 Direction control 5.4 External and remote control requirements 5.4.1 Local controls ... Fortunately, the valve actuator industry is able to automate the full spectrum of valves available with a comparatively smaller number of actuator variants.

6.3 Maximum allowable stem torque (MAST) 7 Actuator data. 7.1 Output torque. 7.2 Maximum rated pressure. 8 Mounting components. 8.1 General. 8.2 Intermediate support. 8.3 Coupling. ... is to provide increased reliability and safety in automated on-off valve operation by defining and standardizing valve torque nomenclature used in actuator ...

If the valve has a higher actuator sizing torque in mid-travel versus at the seat end, then a larger than expected scotch-yoke actuator may be needed. ... If the valve is obstructed from closing, the actuator may have sufficient torque to exceed the maximum acceptable stem torque (MAST) specified by the valve manufacturer. When critical …

of 5.5, 7, and 9 bar as well as the MAST. The MAST and integrity between the valve and the actuator did not pose problems in two cases; the use of at least one of the abovementioned solutions is proposed to ensure integrity between the valve and the actuator in terms of the MAST and actuator torque in the other three cases. Graphical …

As a general rule of thumb, MAST should be. 1.2 times the actuator torque for valves used in general services. 1.5 times the actuator torque for heavy process duties like blowdown; 2 times the …

Maximum Allowable Stem Torque (Mast) The maximum allowable stem torque/trust (MAST) is defined as the maximum torque/trust that can be applied to the valve train without risk of damage, as defined by the valve manufacturer [6, 7, 9, 10].The drive train is defined as all the valve components between the valve operator (manual …

Maximum shaft torque or Maximum Allowable Stem Torque (MAST) is the most force that can be applied to a stem valve before deformation occurs. ... Minimum air – Lowest torque valve of the actuator produced by the air supply. Depending on actuator type, this may be the same value as end of air. Other times it may be the mid-stroke position.

MAST represents the maximum torque that a valve shaft can withstand during operation without risking mechanical failure. Imagine a quarter-turn valve, for …

Valve torque chart ... Gear or actuator mounting plate Stem thrust washer Stem O-rings Seat injection fitting Check valve Seat backup ring Wrench head mounting plate ASME Classes 150–2500 and 5,000-psi valves, 2 to 16 in [50 to 400 mm] 5 Materials list

so ball valve will often have a MAST (max allowabe stem torque) and also BTO (Break to Open) torque required to intiate opening, RTO (Run to Open) the torque required to complete the majotity of the 90° operation and the ETO (End to Open) Torque required to fully open. ... SDV and ESDV valves with a factor of safety of 1.5 for …

Definition of MAST: Maximum Allowable Stem Torque (MAST) is the maximum torque or thrust that can be applied to a valve without risking damage, as specified by the valve manufacturer or supplier. It encompasses all parts of the valve drive between the operator and the closure member, excluding the valve operator itself (e.g., …

1.1 Background. Industrial valves play an important role in fluid control in the piping systems in various industries, such as the oil and gas industry [1, 2].Valves are operated manually by a human operator or automatically by an actuator [].An actuator is a machine or component installed on top of an industrial valve for automatically moving …

For example, in the oil and gas industry, three different application categories for safety margin are commonly designed for the on/off actuator valves: 1. General Duty like Process On/Off valves – the valve will have an actuator with a torque output of at least 1.3 times the operational torque requirement of the valve (+ 130% or x …

The torque of different types of valves is different. There are three types of friction to be considered when calculating the torque of ball valve: ball and seat friction torque; Friction torque of packing on the stem; The friction torque of the bearing on the stem, how to calculate the torque of the ball valve? The total stem torque of the ...

It is maximum allowable torque a stem of a quarter turn valve can be subjected to without mechanical failure. Engineering unit Nm OR lb-in During valve operation, torque delivered by actuator (Pneumatic or electric) at any stage, should not exceed MAST value. If it happens stem may be …

The rule of thumb is typically to choose an actuator rated for the valve's break torque plus 25%. If the actuator exceeds this amount, then it may cause damage to valve components. One big risk is if an actuator exceeds the maximum allowable stem torque (MAST) rating, which can cause the stem to break or deform.

MAST is defined as the Maximum Allowable Stem Torque that a valve stem can undergo without mechanical failure occurring. Description: As many ball valves contain different variations – 90°, 180°, and 360° rotation – MAST is considered when obstruction within a ball valve, i.e. ball, stem, etc., takes place.

• Use the valve torque graphs and verify that the MAST does not exceed the valve's maximum torque at the application maximum differential pressure. Important notes: • For valves complying with API6D and SIL certified packages, the valve maximum torque must not exceed 50% of the MAST figures shown in Table B.

the valve torque and the actuator-produced torque at 7 barg air pressure. Table 1 provides all the relevant valve and actuator torque data, where the torque data have been given considering a full pressure class differential pressure across the valve equal to 50 barg. The valve is in the 22Cr duplex body and internals, including the stem. The ...

This exclusion is the primary reason why MAST values are exceeded. Excessive torque at the stem when sizing actuators will create a need to consider changing stem material. Specifying a higher yield …

Five actuated fail-safe closed ball valves were analyzed in terms of valve and actuator torques at five points and with air pressures of 5.5, 7, and 9 bar as well as the MAST. ... one of the abovementioned solutions is proposed to ensure integrity between the valve and the actuator in terms of the MAST and actuator torque in the other three …

In the Sizing calculations, for some valves the Actuator MAST is exceeding the Valve MAST, which I believe is not desirable. I cannot change my DP on line & cannot reduce my safety factor (2). What is the solution now? ... Having now understood MAST (Maximum allowable stem shear torque), it would seem a bad idea to have the …

MAST is maximum allowable stem torque. It has nothing to do with the valve oeprating torque. It is the maximum torque that can be applied to the stem …

BTO = Break to open (air stroke) BTC = Break to close (spring stroke) MAST = Max stem torque RTO = Running to open (air stroke) ETO = End to open (air stroke) RTC = Running to close (spring stroke) ... 600CL 1 9900 KPA 1A 673.00 VALVE/ ACTUATOR TORQUE SIZING ANALYSIS CHART FOR TRUNNION BALL VALVES PISTON STYLE SCOTCH …

• Use the valve torque graphs and verify that the MAST does not exceed the valve's maximum torque at the application maximum differential pressure. Important notes: • For valves complying with API6D and SIL certified packages, the valve maximum torque must not exceed 50% of the MAST figures shown in Table B.

Keywords Maximum allowable stem torque (MAST) · Valve design · Actuation · Stem material · Stem diameter · Oil and gas · Offshore 1 Introduction to MAST Maximum allowable stem torque/thrust (MAST) is defined as the maximum torque/thrust that can be applied to a valve train without risk of damage, as defined by the valve manufacturer ...

General Duty like Process On/Off valves – the valve will have an actuator with a torque output of at least 1.3 times the operational torque requirement of the valve (+ 130% or x 1.3 safety)

Definition of MAST: Maximum Allowable Stem Torque (MAST) is the maximum torque or thrust that can be applied to a valve without risking damage, as specified by the valve manufacturer or …

Maximum allowable stem torque (MAST), which is the torque required to permanently deform or break the valve stem. ... Minimum air: It is the lowest torque valve of the actuator produced by the air supply. Depending on actuator type, this may be the same value as end of air. Other times it may be the mid-stroke position.

The quantity of torque an actuator can generate is a critical element in determining an actuator's 'rating specifications.' Varying types of actuators can be used to accomplish different functions depending on their torque ratings. ... Therefore, the manual actuator's maximum torque surpassing the valves MAST is not a significant ...