NESL’s Valtest technology enables you to test if each valve is functioning properly, without shutting down your plant. With our unique electronic system you get a record of the valve’s performance under pressure and a certification as to whether it is working as intended. Our process is approved by various authorities including Central Boiler Board. The test is quick, is done in situ, and does not require a drop in pressure or an expensive shutdown.
Hydraulic power pack is used with laptop recorder linked through 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. Valtest system tests the valve without interrupting plant production.
Hot Testing: Valtest online testing system
The Valtest 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 Valtest system provides a certified print out of valve lift pressure and line pressure at the valve.
- Steam Service Valves : Valtest 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 : Valtest 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 : Valtest without Line Pressure
The Valtest system can also be used for cold testing of safety and relief valves i.e. when there is no line pressure.
- 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 Valtest at the beginning of the shutdown to identify those which require overhaul.
- Valtest 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.
Valtest has been acknowledged as an energy saving device by a host of major plants owners who also value plant safety on top most priority. So far more than 40,000 Safety Valves have been tested and calibrated by online Valtest method in India and abroad by NESL.