Why do I need a silver shading ring in a solenoid valve?
A silver shading ring (also known as a shading coil) in a solenoid valve is crucial when controlling reverse osmosis (RO), demineralized, or pure water for several important reasons:
View and buy valves for RO water here.
1. Prevents Chatter and Ensures Smooth Operation
Solenoid valves operate by using an electromagnet (coil) to pull a plunger, opening or closing the valve. However, alternating current (AC) power can cause issues due to the way it cycles between zero and peak voltage.
Without a shading ring, the electromagnetic force drops to zero at every AC cycle (50 or 60 times per second), which can cause the plunger to vibrate (chatter) or produce a buzzing sound.
A silver shading ring acts as an auxiliary conductor, creating a small secondary magnetic field that keeps the plunger held in place even when the main AC field is at zero. This eliminates chatter, ensuring the valve operates smoothly and quietly.
2. Corrosion Resistance in Pure Water Applications
Pure, demineralized, or RO water is highly corrosive to many metals due to its lack of dissolved ions, which makes it aggressive in leaching elements from exposed metal surfaces.
Traditional shading rings are often made from copper or brass, which can corrode quickly in pure water environments.
Silver is highly resistant to corrosion and oxidation, making it the ideal material for a shading ring in applications involving ultrapure water.
An additional option is to use a solenoid tube without shading ring, but these can only function with a DC (Direct Current) coil.
3. Prevents Material Leaching and Contamination
When controlling pure water, it's critical to avoid contamination that can alter water quality, especially in:
Pharmaceuticals
Semiconductor manufacturing
Laboratories
Medical applications
Copper-based shading rings can leach ions into the water, compromising purity.
Silver is chemically stable and does not leach harmful substances, maintaining water purity.
4. Increases Valve Lifespan and Reliability
The harsh nature of pure water can cause rapid degradation of standard solenoid valve components.
A silver shading ring provides long-term durability, reducing maintenance costs and extending valve life.
5. Reduces Risk of Sticking and Seizing
In pure water applications, solenoid valve components can be affected by:
Scale formation
Deposition of trace materials
Surface oxidation on metals
A silver shading ring helps prevent sticking and seizing by reducing oxidation and ensuring consistent magnetic performance over time.
Conclusion
Using a silver shading ring in solenoid valves for reverse osmosis, demineralized, or pure water systems is essential because it:
Prevents valve chatter by maintaining a stable magnetic field.
Resists corrosion from aggressive pure water.
Maintains water purity by avoiding contamination.
Extends valve lifespan by improving durability.
Reduces sticking and seizing, ensuring reliable operation.
This makes silver the best choice for shading rings in high-purity water control systems, guaranteeing both performance and longevity.