Powell Fabrication & Manufacturing, Inc.

Shutdown System for Tank Cars & Bullet Tanks


Versión en Español

How does the UniPro™ System Accommodate Tank Car Valves with Different Torque Requirements?

 

Answer: There are 2 options.

UniPro LTThe first involves the UniPro™ LT low torque actuator. This valve actuator develops only enough torque to seat and seal tank car valves with soft Teflon seats. The UniPro™ LT operates on the same air/nitrogen supply system and at the same pressure as the UniPro™ Standard. It is designed to close valves manufactured by Beltech, Descote, Midland, Eagle and Rego. The UniPro™ LT will close these valves in several seconds with sufficient torque to seat and seal them but not so much torque that they cannot be reopened by hand. An added feature of the UniPro™ LT is that it is light weight. At only 14 lbs, it weighs just half as much as the UniPro™ Standard. The UniPro™ LT can be mounted in seconds without tools and can be removed from the valve handle for hand valve operation without having to readjust it when replaced on the valve handle. The UniPro™ LT should only be used when the valves to be serviced require no more than hand torque to operate them.

The second solution utilizes the UniPro™ Standard actuator, its High Torque Valve Adapter and its Torque Limiting Valve Adapter.

UniPro Valves

This combination can be used to close either high or low torque valves. When tank cars have high torque ACF valves, the UniPro™ Standard (with its High Torque Valve Adapter) supplies up to 120 lb-ft of torque to close these metal seated valves. However, when tank cars arrive with the soft seated valves described above, the High Torque Valve Adapter can be quickly replaced by the Torque Limiting Valve Adapter by pulling one hitch pin and making the swap.

Like the UniPro™ LT, the Torque Limiting Valve Adapter allows the UniPro™ Standard to deliver only enough torque to the valve handle to seat and seal it without damaging the soft seat material.

Though heavier than the UniPro™ LT (UniPro Standard weighs 28 lbs), the UniPro™ Standard is a must when both high and low torque valves must be serviced.

Customers sometimes ask if they can lower the operating pressure used with the UniPro™ Standard actuator and the High Torque Valve Adapter in order to reduce its torque output to a level that will not harm the soft valve seats on the low torque valves. The answer to this question is no! All UniPro™ valve actuators utilize air motors. Every air motor is rated at a specific air pressure. The UniPro™ actuators all have air motors rated at 90 PSIG.

Another trait of all air motors is their threshold pressure. This is the pressure below which the air motor could fail to start turning when pressurized. Our tests have indicated that to achieve the low torque required with the High Torque Valve Adapter on the UniPro™ Standard actuator (to prevent damage to the Teflon valve seats in the low torque valves named above), the pressure must be turned down to a level below the threshold pressure of the air motor in the UniPro™ Standard. Most of the time, the motor did turn when activated at this low pressure during our tests, but occasionally it did not! For this reason, we recommend the use of the Torque Limiting Valve Adapter used at 90 PSIG with the UniPro™ Standard actuator for low torque, soft seat valves, or the UniPro™ LT can be used at 90 PSIG. Neither combination will harm the soft seats, and both will start to turn when activated.

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