Valve fail
Image Source: Dombor Valve
When a signal loss occurs, the valve opens. A fail open valve would prevent upstream pressure from building up in a back pressure application, like holding pressure on a separator. When the signal fails, the valve closes. A fail-closed valve would safeguard downstream equipment from excessive force in a pressure-reducing application like air compressor suction control.
Fail close or fail open: how to determine
Fail-close valves block the fluid flow, while fail-open valves allow. A stem indicator is the valve failure position.
- Valve fails to close if the indication arrow is “closed” without pressure.
- Valve fails open if the indicator arrow is “open” without force.
The breather plugs show control valve status.
- Valve actuator bottom breather plug fails.
- Valve actuator’s top breather plugs break.
What is the control valve failure open?
If a signal or power is lost, a valve opens. Air pressure closes these valves. The valve opens automatically when air pressure drops. Firefighting systems use this valve. After the fire cuts electricity, the valve opens, and water flows, usually allowing the fire extinguisher system to work.
Fail open valve symbol
Image Source: Assured Automation
When signal loss occurs, the valve opens.
Fail open valve example
Image Source: SIO
In situations, fail open valves can stop fluid or gas flow. A fail-open valve can stop toxic chemicals or gas from escaping a pipeline breach.
Fail close valve symbol
Image Source: Assured Automation
When failure conditions are discovered, a device or system is set to shut down and stop operating.
Fail close valve example
Image Source: SIO
Failing closed refers to a setting that causes a device or system to physically or electronically shut down and stop functioning when failure conditions are discovered.
Industrial valve repair
Industrial valves are mechanical tools to control system liquid or gas flow by opening, closing, or partially obstructing channels. The process flow is made safe and reliable by valves. The flow of different resources, such as oil, gas, water, or pulp, is often controlled by large plants or factories with numerous pipelines. The industry depends on valves at this point.
Gate valve repairs: how to fix a gate that doesn’t close
Sediment inside gate valves prevents it from shutting. Sediment lodges between the lowering gate and the valve body. Ball valves don’t have this issue since they act differently than gates that lift and drop inside the valve body.
- If silt or mineral deposits prevent a gate from closing, try rinsing the valve.
- Open a sink faucet to turn on the water supply.
- Open and close the valve gently. Release the packing nut above the valve body and around the valve stem to liberate the valve handle.
- Remember to tighten it after that. Loosening it one turn should work.
- When the gate is dropped, water will wash away some silt. As long as excessive force is not used, this is entirely safe.
- Regularly opening and closing a gate valve prolongs its life.
- It exercises the valve. Experienced building managers integrate this into routine maintenance. Exercise water valves to prevent silt buildup.
Replace a gate valve with a ball valve
A ball valve can replace a gate valve. To remove pieces, use a torch.
- Turn off and drain the water. Open the valve.
- Heat the valve-pipe junction.
- Try moving the valve with large channel locks. If so, remove it.
- Cutting the pipe and pulling off the valve may be easier than heating a neighboring elbow and moving it laterally.
- To solder the new valve, clean, flux, and heat the joints.
- Like the valve, you can solder a repair connection over a pipe cutter.
- Apply heat with the valve open.
Multi-port valves are used to redirect media or provide several media sources. Ball valves are faster for on/off control than gate valves since they require a 90° turn to control the ball position.
How to fix a leaking ball valve?
To troubleshoot a leaky ball valve in your piping system, determine the leakage’s cause. Here’s how to repair a ball valv:
- Stop, fluid flow.
- Remove, stem handle.
- Unscrew, packing nut.
- Check the packaging and internal components. Check for damage. Diagnose the valve and choose a solution:
- Replace worn packing materials.
- Replace it.