control valve overhaul
Control valves are an important part of the processing industries and their flow control is key to ensure plant reliability and profitability. With our knowledge and experience we offer a complete overhaul service on and offsite depending on your needs.
When undertaking the overhaul of your control valve it will be initially tested to highlight any previous issues before been stripped and assessed. The parts are cleaned and measured as part of our inspection and details logged in a report. An update of your service will be given at this point if it is deemed necessary from our inspections.
Lapping and machine repairs will be carried out either through recommendations or a general service ensuring the components are fit for use.
Onto rebuild, final test and completion it will be processed through tests before being repainted back to an OEM standard paint colour. Your Valve inspection report will be completed, provided and stored on our database to assist in future recommendations to servicing.
Final Calibration and stroke checks are carried out on your valves to ensure your valve works efficiently.
Frequently Asked Questions
A control valve is used to regulate the flow of fluids, such as gas, oil, water, and steam. The valve stem moves, altering the size of the passage and this increases, decreases or holds the flow steady. The control valve opening is altered whenever the process parameter being controlled does not equal the value it is meant to be (the set point).
Flow Characteristic describes the relationship between the valve coefficient (CV) and the valve stroke. As a valve opens, the flow characteristic allows a certain amount of flow through the valve at a particular percentage of the stroke.
General onsite checks to the function of a control valve are as follows.
1- Check whether the valve is properly assembled and connected to both the actuator and positioner linkage.
2- Instrument mains air is checked ensuring adequate supply for the valve operation.
3- All pipework and fittings are inspected during operation to ensure leakage is not present.
4- 4 M/A current signal is applied, and the valve stem should still read 0% travel.
5- When 20 M/A is applied the valve stem should have travelled 100%.
MORE SERVICES
We undertake the full overhaul inspection and testing of all Pressure Safety Relief Valves.
We service Manual, Automated and Check valves to achieve all isolation requirements.
Provided by Outage Project Support, Conditional Walkdowns, Asset Tagging & Valve Spares.