Wiring Method of Explosion-Proof Solenoid Valve

Explosion-proof solenoid valves are essential components in industries where hazardous environments exist, such as chemical plants, oil refineries, and mining operations. These valves are designed to operate safely and efficiently, preventing electrical sparks or heat from igniting explosive gases or dust. In this article, we will explore the wiring methods for two common types of explosion-proof solenoid valves, as well as important installation instructions for high-temperature solenoid valves to ensure optimal performance and safety.

1. Lead-Type Explosion-Proof Solenoid Valve Wiring Method

A lead-type explosion-proof solenoid valve has a power line drawn from inside the explosion-proof coil housing. The length of the lead is generally around 1.5 meters, though some models allow for longer outgoing lines.

Wiring details:

• The lead consists of three-core wires:
  • Yellow: Ground wire
  • Red and Green/Black/Blue: Power cables (the power supply is not polarity-sensitive, so it can be connected in any direction).

2. Connector-Type Explosion-Proof Solenoid Valve Wiring Method

For an ASCO explosion-proof solenoid valve with a connector type, there are three ports inside the explosion-proof coil housing:

• Two power cables
• One ground wire

Wiring method:

• Field wiring can directly enter the explosion-proof coil housing through the standard connectors.

How the Valve Works:

• When energized: The electromagnet pulls the connecting rod, causing it to rotate with the rotating shaft. This action opens the pilot valve, which then opens the main valve.
• When powered off: The armature weight and return spring cause the pilot valve to reset, closing the pilot hole. The pressure difference causes the main valve to close.

Normally Closed Operation:

• When the coil is energized, the pilot spool is sucked in, the pilot hole opens, relieving pressure on the valve, and the piston is pushed by the medium pressure in the lower chamber, opening the valve.
• When the coil is powered off, the spring resets the pilot spool, the pilot hole closes, and the valve is closed due to the pressure in the upper chamber and the return spring.

Normally Open Operation:

• When the coil is energized, the pilot hole closes, and the upper chamber is pressurized by the piston and spring force, keeping the valve closed.
• When the coil is powered off, the spring resets the pilot spool, the pilot hole opens, releasing pressure in the upper chamber and allowing the medium pressure in the lower chamber to push the piston, opening the valve.

Instructions for High-Temperature Solenoid Valve Installation

1. Before Installation:
   • Read the manual and check the solenoid valve’s type and specifications.
   • Flush the pipeline.
2. Valve Installation Direction:
   • The direction of medium flow should match the arrow on the valve body.
   • The solenoid portion should be positioned straight up.
3. Avoid Low Recess Installations:
   • Do not install the valve in the low recess of the pipeline, as steam condensate and impurities can obstruct valve action.
4. Explosion Risk Warning:
   • This valve cannot be used in explosive environments.
5. Space for Maintenance:
   • Ensure sufficient space around the valve for heat dissipation, daily maintenance, and regular servicing.