Posted on: 3 September 2015
Solenoid valves are among the most common valves used in modern industrial processes, so chances are high that if you work with fluid control on the job, you will encounter a solenoid valve. If you encounter a solenoid valve that leaks, you should know that repair is not a difficult job. Many leaks are caused by a foreign object obstruction, so opening the valve and performing a thorough cleaning is the first step to resolving a problem. Below are the tools you will need as well as how to perform the cleaning:
Tools and materials needed
Hex key set
Clean shop towel
Plastic bristled brush
Step-by-step cleaning procedure
1. Shutdown upstream flow and lock-out valves and controls - No matter where the solenoid valve is located in your particular system, the upstream flow of fluid should be shut off before attempting any work on the valve. Be sure to follow appropriate lock-out and tag-out procedures to prevent an accidental discharge into your workspace or potential contamination of a product.
In addition, since solenoid valves are powered by electrical current, you should ensure that all valve controls are deactivated or disconnected to prevent electrical shock. Never attempt to work on an energized solenoid valve.
2. Locate and remove the solenoid electrical supply - Solenoid valves are connected to a power source via a plug, and this plug can often be removed by simply pulling it away from the solenoid coil. Other solenoid valves may require a screw or other fastener be removed first, so be sure to locate and remove these before applying force to the plug.
3. Remove the solenoid coil - The solenoid coil contains the magnetic coil that moves the valve plunger up during operation. Remove the coil by unscrewing it from the valve cover, and keep your free hand near the coil in case the plunger or plunger spring are released under tension. Carefully slide the plunger and spring out of the coil, and set these items aside in a safe location.
4. Remove the diaphragm - Beneath the spring and plunger lies the diaphragm. This membrane seals the valve orifices that permit fluid to flow when the valve is activated. Lift the diaphragm out of the top of the valve body to avoid tearing it.
5. Remove the valve cover - The valve cover will be fastened by hex screws or bolts, so remove these next. Be careful when lifting the cover so that you don't damage the gasket that seals the cover to the body of the valve.
6. Inspect the components - After removing the solenoid valve parts, it is important to spend a few moments inspecting the parts for signs of wear and tear. Here are a few particular points to check:
Plunger spring - Evaluate the spring for signs of metal fatigue, such as cracking or inability to deform properly or rebound after tension is released.
Diaphragm - The diaphragm should be pliable and flexible. Cracking or drying are signs that replacement is necessary, as are pinholes or other damage.
Valve orifices - All valve orifices should be free of any deposits or debris, and they should not show signs of enlargement due to erosion. A flashlight will enable you to see through the openings much easier.
7. Clean the components - Once you have inspected all the parts and are satisfied they are still viable, then you need to clean the components with mineral spirits. Place all parts in a shallow container containing mineral spirits and allow them to soak for ten minutes. Use a plastic bristle brush to scrub them thoroughly. For orifices, slide the end of a pick into them to remove debris or deposits. Never use a drill bit or other cutting tools to clean an orifice as it may impair the function of the valve.
Once the metallic parts are cleaned, set them on a clean cloth and allow them to dry. The diaphragm should be rinsed in hot water to remove traces of mineral spirits and prevent damage to the material.
8. Reassemble the valve - In reverse order from above, reassemble the valve. Reconnect electrical power and check for functioning before resuming its use with fluids.Share