The Trevitest System

Principle

Hydraulic power pack is used with pen-recorder linked with electronic transducer that applies force to the valve spindle, to overcome spring tension. The set pressure is regulated by combining recorded data, knowledge of valve seat area and line pressure of the valve. Trevitest system tests the valve without interrupting plant production.

Hot Testing: Trevitest on line testing system

The Trevitest system has been designed to test safety and relief valves on line under normal operating conditions. This is called hot testing. Service experience shows that the test results are within plus or minus one percent of the set pressure when the equipment is operated by trained technicians. The Trevitest system provides a certified print out of valve lift pressure and line pressure at the valve.

Major Application

Steam Service Valves: Trevitest is capable of testing safety valves at normal operating pressure. It also tests on line safety valves which cannot be tested by increasing system pressure - for example, reheater valves and primary side reactor valves.

Clean Service Process Valves: Trevitest can be used to diagnose safety and relief valves which require maintenance while the plant is running normally - prior to the scheduled shut down. Valves which were found to require overhaul can be tested after they have been returned to the line in order to verify the bench test set pressure.

Cold Testing: Trevitest without Line Pressure

The Trevitest system can also be used for cold testing of safety and relief valves; that is, when there is no line pressure. Before such testing takes place, a calculation is made knowing the value of spindle geometry and material to ensure that the test can be carried out safely. From the information recorded during the cold test, the set pressure can be determined.

Major Application

• Safety and relief valves on new plant can be pre-commissioned without removing the valves from the line.

• Valves which cannot be tested on line can be tested by Trevitest at the beginning of the shut down to identify those which require overhaul.

• Trevitest can also be used to test valves in the workshop following the conventional bench test to give a "finger print" of the valve. After the valves are returned to their position at site a further test can be carried out and the graph compared with the "finger print" to verify there has been no change in the setting.

Trevitest has been approved as an energy saving device by a host of other departments and institutions concerned with Plant Safety along with important bodies like:

• Central Boiler Board of India
• A.O.T.C.
• HSE, Llyods (U. K.)
• T. U. V. (W. Germany)
• ANCC (Italy)