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.
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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.
2018-2-16 · the maximum rated torque output of the actuator. The possibility exists, that should the valve become immobilized during rotation, the actuator could exceed the maximum allowable valve input torque rating. If this possibility is a concern, your appliion needs further review. Once the maximum torque requirements, its
Above Actuator is Complete with Bracket (ISO Mounting) and high tensile Adaptor All Torque Values are theoretical, however where required we will torque test prior to despatch. The real valve torque value can be higher depending upon the following listed factors as these factors can drastically increase (or decrease) the torque.
2018-11-25 · This is the amount of torque required to seat a valve into its closed position. Maximum Allowable Stem Torque (MAST) The torque required to permanently deform or break the valve stem. Safety Factor. A given multiple of the valve’s operating torques to ensure proper operation of the actuator.
2018-11-14 · A valve actuator is the mechanism for opening and closing a valve.Manually operated valves require someone in attendance to adjust them using a direct or geared mechanism attached to the valve stem. Power-operated actuators, using gas pressure, hydraulic pressure or electricity, allow a valve to be adjusted remotely, or allow rapid operation of large valves.
The result is a dimensionally large scotch-yoke actuator, producing extremely high break torques resulting in the maximum torque output from the actuator reaching or even exceeding the valve MAST
2014-4-4 · the valve/actuator manufacturer (service factor) and actuator-valve torque safety margin. Many valve manufacturers utilize their own safety cont ingency in addition to the user’s specifiion.
ETC – closing torque: the torque required to reseat a closing valve. 85% of stated BTO torque* RTC – running torque: the torque needed to keep the ball moving through it’s travel. 50% of stated BTO torque* MAST – Maximum stem torque *Average guide based on
Move the valve closure meer (disc, ball, or plug) to the desired position. Not only must the actuator provide enough torque or thrust to move the closure meer under the most severe conditions, it must also be fitted with the appropriate controls to direct it. Hold the valve
2013-8-7 · when selecting an electric actuator for a ball valve. Actuator stall torque is the amount of torque produced by the actuator just prior to the point where the motor stalls. Select the actuator whose startup torque output exceeds the breakaway torque requirements of the valve. Electric actuator torque outputs are shown on page 12.
2018-6-4 · The torque figures provided represent the required torque to open and re-seat the valve. The figures provided are based upon water and other lubriing fluids, and include a factor of safety. For gases, non-lubriing media and dry powders increase the torque figures by 1.3 Eurotorc offer a valve with either a 3 Bar or 6 Bar reduced diameter
2018-11-26 · In this situation, a pneumatic actuated butterfly valve had a MAST (Maximum Allowable Stem Torque) problem. In fact, MAST should be higher than the actuator torque. However, in this case, an 8" Class 150 (Pressure Nominal 20Barg) Carbon steel body valve was receiving a maximum torque value of 1193 ft/lb (1618 N.m) from the actuator.
2012-5-22 · 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 without permanently deforming it. In a perfect world, the maximum actuator output torque would be less than the MAST so that the actuator can never twist the stem and prevent proper seating of the
2015-5-14 · ETO – open breakout torque: the torque required to move the valve from the fully open position. 70% of stated torque* ETC – closing torque: the torque required to reseat a closing valve. 85% of stated torque* RTC – running torque: the torque needed to keep the ball moving through it’s travel. 50% of stated torque* MAST – Maximum stem
2018-1-25 · This is valve manufactures responsibility to calculate and provide valve MAST during engineering stage and ensure torque delivered by actuator is always less than the valve MAST. During offer stage valve MAST furnished in performance table shall be considered as basic value.
2016-2-16 · Valve Dimensions and Operators 10 Material Example 12 Metal Seated 3-Piece Body Trunnion Mounted Ball Valves T60M Series（1） 13 Component Drawing 14 Design Features 15 Construction and Material 16 Valve Dimensions and Operations 18 Pressure-Temperature Ratings 20 Engineering Data 21 Dimensions of Actuator Mounting Pads 22
2015-6-22 · an actuator for a valve, the MAST and maximum torque/thrust are compared to ensure compatibility of design and that it is imperative that information described below is exchanged, to ensure that the necessary entities provide and receive the required information for the supply of an actuator, mounting kit or actuated valve assely.
The actuator output torques have to be greater than the valve torques through all the travel and in both directions open and close. And, as described in my first blog, the actuator maximum torque should not exceed the valve maximum allowable stem torque (MAST). When sizing an actuator, always request the torque values and the recommended safety