This is part of a series of articles addressing questions we get from our customers about valves and valve products. Read the previous articles here:
- How often should you repair or replace pressure relief valves?
- Answers to three common questions about pressure relief valves
In this article, we turn our attention from pressure relief valves to line valves, specifically, to gate and non-return valves.
Gate valves and non-return valves (aka check valves) are widely used in a variety of applications. Gate valves are the most common types of valves found in industrial applications, especially along pipelines. They provide on/off flow control and are often used to isolate parts of a system. Non-return valves prevent backflow by allowing flow in only one direction. They are frequently found in chemical, power, and nuclear applications.
Since gate valves and non-return valves perform critical tasks, it’s essential that they work right every time. You can avoid problems with your gate valves and check valves — and the consequences of those problems — by following a preventative maintenance program. But if you find yourself in a situation where your valves won’t shut off completely, here are four options for repair.
1. Send the valve to an authorized repair shop
If the valve can be removed easily, you can send it to an authorized repair shop where technicians will repair and test the valve to the manufacturer’s specifications and your application requirements.
2. Repair the valve in the field
If the valve can’t be removed easily, for example, if it’s welded in place, you can have it repaired in the field. This is much less expensive than cutting the valve out of the line for repairs and then having to weld it back in. For flanged gate valves, you usually have the option to repair either in the shop or in the field.
3. Machine the wedge back to original factory conditions
If the valve has a wedge, that wedge might not be positioned at the correct angle, causing it not to seal fully on the sealing surface. A technician can re-machine the angles of the wedge back to the original factory conditions so that it will fit properly.
4. Check the actuator
It’s possible that the problem lies not with the valve, but with the actuator. For example, the limit switch that opens and closes the valve might not stop at the right mark. If this is the case, you’ll need a technician who specializes in actuator repair.
Our technicians are factory-trained and certified to repair all types of valves and actuators, both in the shop and in the field. Contact us for more information about our line valve repair services.