What Is A Solenoid Valve? Introduction To Solenoid Valve Types

Solenoid valves are electromagnetically‑controlled industrial devices widely used in industrial control systems to regulate medium flow direction, flow rate, flow velocity and other process parameters. Controlled by electromagnetic effect, they often work with relays for signal‑based control. Combined with different control circuits, solenoid valves achieve accurate and flexible process control. There is a wide variety of solenoid valves serving different positions in control systems, including check valves, safety valves, directional control valves and flow control valves.

1. Solenoid Valve Classification By Working Principle

Based on operating principles, solenoid valves fall into three major groups: direct‑acting, step‑by‑step direct‑acting, and pilot‑operated.

• 1. Direct‑acting Solenoid Valve

  Principle: When energized, electromagnetic force lifts the closing member off the valve seat to open the valve. When power is cut off, electromagnetic force disappears and spring force presses the closing member against the seat to close the valve.

  Features: Works reliably under vacuum, negative‑pressure and zero‑differential‑pressure conditions; nominal port size generally no larger than 25 mm.

• 2. Step‑by‑Step Direct‑acting Solenoid Valve

  Principle: Combines direct‑acting and pilot‑operated structures. Under zero inlet‑outlet differential pressure, electromagnetic force lifts the pilot small valve and main‑valve closing member sequentially to open the valve. With startup differential pressure across ports, energization opens the pilot small valve; pressure rises in main‑valve lower chamber and drops in upper chamber, and medium pressure pushes the main valve open. When de‑energized, spring or medium pressure pushes closing member down to shut off flow.

  Features: Reliable operation under zero‑differential‑pressure, vacuum and high‑pressure conditions; relatively high power consumption and must be installed horizontally.

• 3. Pilot‑operated Solenoid Valve

  Principle: Upon energization, electromagnetic force opens the pilot orifice. Pressure in upper chamber drops rapidly, creating pressure difference across the closing member (lower pressure on top, higher pressure below). Medium pressure pushes the closing member upward to open the valve. When de‑energized, spring force closes the pilot orifice. Inlet medium pressure flows into upper chamber through bypass orifice, reversing the pressure difference, and medium pressure pushes the closing member downward to close the valve.

2. About Us

Shenzhen Juchang Precision Co., Ltd. is located in Pingshan District, Shenzhen. It is a high‑tech enterprise focusing on R&D, manufacturing and precision machining of high‑end precision ceramic pumps, ceramic plunger pumps, ceramic filling pumps, ceramic injection pumps, as well as alumina and zirconia precision ceramic parts. Equipped with full‑set core manufacturing equipment for isostatic pressing, high‑temperature sintering, 5‑axis CNC machining and mirror polishing, we solve challenging fluid‑transport tasks featuring strong corrosion, heavy abrasion, high cleanliness and ultra‑high precision. Our products serve high‑end industrial sectors including lithium‑ion new‑energy, pharmaceutical & medical, semiconductor, fine chemicals and environmental water‑treatment. We supply both standard products and customized one‑stop fluid‑control solutions.

Product Advantages

• Ultra‑high dimensional accuracy: Machining tolerance up to ±0.001 mm, ceramic mirror‑polishing Ra ≤0.025 μm. Stable fitting clearance supports long‑term zero‑leakage performance;

• Excellent corrosion resistance without ion leaching: High‑purity zirconia / alumina ceramics deliver superior chemical inertness against strong acids and alkalis, with zero‑metal‑ion release to satisfy high‑cleanliness requirements for pharmaceutical and lithium‑battery applications;

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• Rigorous quality‑control system: Complete precision‑testing instruments are deployed. Every production batch undergoes performance inspection to guarantee consistent product quality.

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