How To Solve The Problem of Leakage of Solenoid Valve After Closing?

1. Seal Wear or Damage

O-rings, diaphragms, or seat seals degrade over time due to friction, chemical corrosion, or high-temperature exposure. Hard particles in the fluid scratch or embed in the seal, creating micro-gaps.

Solution:

Replace Seals with Compatible Materials, use FKM (Viton) for oil/gas applications; EPDM for water/steam; PTFE for chemical resistance.If a valve in a fuel system with NBR seal leakage should switch to FKM to withstand gasoline corrosion.

2. Implement Regular Maintenance:

Schedule seal replacement based on duty cycle (e.g., every 10,000 cycles for high-use valves). Add a pre-filter upstream to trap particles.

3. Valve Core Misalignment or Deformation

Mechanical stress from improper installation warps the valve body.

High fluid pressure or rapid actuation causes the plunger to bend, preventing full seating.

Solution:

Verify Installation and Alignment, ensure the valve is mounted perpendicular to the pipeline, avoiding lateral forces.Use a torque wrench to fasten connections within manufacturer specs.

Upgrade to Reinforced Designs, Choose valves with stainless steel plungers (e.g., 316 SS) instead of brass for high-pressure applications (>10 bar). or chose spring-loaded plungers with guide sleeves to maintain centering.

4. Contamination or Debris Accumulation

Particles in the fluid lodge between the seal and seat, creating leakage paths. Corrosion byproducts rust from iron pipes accumulate in the valve chamber.

Solution:

Clean the Valve Internals.

Disassemble the valve (if serviceable) and rinse components with isopropyl alcohol.

Use ultrasonic cleaning for stubborn deposits

5. Inadequate Closing Force

Low voltage supply reduces solenoid magnetic force (e.g., a 24V valve operated at 20V). Weakened return spring (due to fatigue or high temperature) fails to push the plunger against the seat.

Solution:

Stabilize Power Supply, Use a voltage regulator (±5% tolerance) and check wiring for voltage drops (e.g., <0.5V in 24V circuits). Replace or Adjust Springs, select springs with higher force constants.

6. Material Compatibility Issues

Fluid chemicals degrade seals or valve bodies (e.g., acetone dissolving NBR O-rings). Thermal expansion mismatches between materials (e.g., plastic body vs. metal seat in high-temperature fluids).

Solution:

Select Corrosion-Resistant Materials:

Fluid Type Recommended Materials

Acid/alkali PTFE (body), PFA (seal)

Steam     316 SS (body), FKM (seal)

Oxygen     Stainless steel (passivated), Vespel

By addressing these factors systematically, internal leakage can be minimized, ensuring valve reliability and system efficiency.