Wuxi Huatong Pneumatic Manufacture
Pneumatics/Solenoid Valve/Cylinder
Pneumatic Directional Control ValveOperation & Maintenance Guidelines1. Before use, inspect components for shipping damage, then install.2. When using solenoid valves, verify supply voltage meets specifications. During machine commissioning, manually test the valve first using a manual override, then proceed to electrical testing.3. Protect valves from dust ingress. Install silencers or exhaust throttle valves on exhaust ports. Ensure proper lubrication.4. When using metal tubing, thoroughly clean internal surfaces to remove metal chips, dust, and oil residue.
Solenoid Valve Installation Notes1. Ensure the flow arrow on the valve body matches the medium direction. Do not install in areas exposed to direct water dripping or splashing. Mount the valve vertically with the coil facing upward.2. The valve must operate reliably within a power supply fluctuation range of -10% to +15% of rated voltage.3. After installation, ensure no reverse pressure differential exists. Cycle the valve electrically several times to reach operating temperature before full commissioning.4. Thoroughly flush pipelines before installation. The medium must be clean—install a filter upstream of the valve.5. Install a bypass line to maintain system operation during valve maintenance or failure.
Working Principle: A solenoid valve contains a sealed chamber with multiple ports connected to different fluid lines. A movable plunger sits between two electromagnetic coils. When one coil is energized, it attracts the plunger, opening or closing specific ports. The inlet is normally open, allowing fluid (oil, air, etc.) to flow into selected discharge lines. Fluid pressure then drives a piston in a cylinder, which moves a rod to actuate mechanical devices. Thus, controlling the solenoid current controls mechanical motion.ClassificationBy medium/application: hydraulic, pneumatic, steam, gas, oil, fire-protection, refrigeration, corrosion-resistant, high-temp, high-pressure, zero-differential, cryogenic, vacuum, etc.By internal structure: pilot-operated, direct-acting, compound, self-latching, pulse, bistable, bidirectional, etc.By body material: cast iron, brass, cast steel, full stainless steel (304/316), non-metallic (ABS, PTFE).By pressure rating: vacuum (-0.1~0 MPa), low (0~0.8 MP...
In pneumatic (or hydraulic) circuits:A 2/3-way solenoid valve has: 1 inlet (from air supply), 1 outlet (to actuator), and 1 exhaust port (typically fitted with a silencer; optional if noise is acceptable).A 2/5-way solenoid valve has: 1 inlet, 1 forward outlet + 1 reverse outlet (to drive double-acting cylinder), and 1 forward exhaust + 1 reverse exhaust (with silencers).For small automation equipment, 8–12 mm industrial air tubing is typical. We recommend using our company’s reliable brand of solenoid valves.In electrical terms:2/3-way valves are usually single-coil; 2/5-way valves are typically double-coil. Common coil voltages: DC24V, AC220V.2/3-way valves come in NC (closed when de-energized) and NO (open when de-energized) types.• NC 2/3-way: Energize → open; de-energize → close (“momentary”).• NO 2/3-way: Energize → close; de-energize → open (“momentary”).2/5-Way Double-Solenoid Operation:Energize “forward” coil → forward port opens and latches (remains open after ...
I. Reliability1. Choose between normally closed (NC) and normally open (NO). NC (open when powered) is standard. Use NO (closed when powered) only when the valve must remain open for long durations with very brief closures.2. Life cycle testing is typically a type test. Note: China lacks a dedicated professional standard for solenoid valves—select manufacturers carefully.3. For high-frequency, fast-response applications, choose direct-acting valves. For large ports, select “fast-response” series.II. Safety1. Standard solenoid valves are not waterproof. Specify waterproof models if needed (customizable).2. The valve’s rated pressure must exceed the system’s maximum operating pressure to ensure longevity and safety.3. For corrosive fluids, select full stainless steel construction.III. EconomyMany valves are interchangeable. Among options meeting reliability, safety, and suitability criteria, choose the most cost-effective solution.
Normally-closed (NC) multi-media solenoid valves use an NC pilot solenoid. Normally-open (NO) versions, used where rapid closing is critical, employ an NO pilot solenoid.NC Design – Working Principle & Features:When de-energized, the plunger closes the pilot drain port under spring force. Inlet pressure (P) flows through a small orifice into the diaphragm chamber, creating higher pressure above the diaphragm. Combined with spring force, this pushes the diaphragm down to seal the main valve seat.When energized, the pilot opens, venting the diaphragm chamber. Since the pilot vent orifice is larger than the inlet orifice, chamber pressure drops rapidly. When upward force from P exceeds downward force, the diaphragm lifts, opening the main valve.NO Design – Working Principle:When de-energized, the plunger opens the pilot port and closes the vent (R). The diaphragm chamber vents, allowing inlet pressure to lift the diaphragm and open the main valve.
Select the solenoid valve switching mode based on the required control function for a double-acting cylinder:1. 2-Position, Single-CoilReturns to original (spring-return) position when de-energized.2. 2-Position, Double-CoilSpool shifts to the side with power applied; retains position when unpowered (“memory” function).3. 3-Position, Closed Center (Double-Coil)When unpowered, spool centers and blocks all ports. Powering either coil shifts spool to that side.4. 3-Position, Exhaust Center (Double-Coil)When unpowered, spool centers: supply blocked, cylinder ports vented to atmosphere. Powering either coil shifts spool accordingly.5. 3-Position, Pressure Center (Double-Coil)When unpowered, spool centers: supply connected to both cylinder ports (holds load). Powering either coil shifts spool to that side.
Normally Closed (NC) 2/3-Way Solenoid Valve: When the coil is energized, the air circuit opens. Once de-energized, the circuit closes immediately—this is “momentary” or “jog” operation.Normally Open (NO) 2/3-Way Single-Solenoid Valve: When the coil is energized, the air circuit closes. Once de-energized, the circuit reopens—also “momentary” operation.Double-Solenoid 2/5-Way Valve: Energizing the “forward” coil opens the forward air path (air exits the forward port). Even after de-energizing this coil, the valve remains in this position—latching until the “reverse” coil is energized.Similarly, energizing the “reverse” coil opens the reverse path and latches it until the “forward” coil is re-energized. This behavior is known as “self-locking” or “memory” function.Due to this latching characteristic, when designing electromechanical control circuits or PLC programs, the solenoid coil only needs to be pulsed for 1–2 seconds. This minimizes coil heating and significant...
Troubleshooting a 2/3-Way Solenoid Valve FailureI. Valve Does Not Operate When Energized• Check power wiring → reseat connectors• Verify supply voltage within ±10% tolerance → adjust• Coil desoldered → resolder• Coil shorted → replace coil• Incorrect pressure differential → adjust ΔP or replace valve• Fluid temperature too high → install high-temp valve• Contaminants jamming spool/plunger → clean; replace seals if damaged; install filter• Excessive viscosity, cycling frequency, or end-of-life → replace valveII. Valve Fails to Close• Damaged seals on spool/plunger → replace• High fluid temperature/viscosity → select appropriate valve• Contaminants in valve → clean• Spring fatigue or deformation → replace spring• Blocked balance/throttle orifice → clean• Excessive cycling or end-of-life → upgrade modelIII. Other Issues• Internal leakage → inspect seals and spring assembly• External leakage → tighten fittings or replace seals• Audible noise when energize...
Choose valve type based on actuator and application: use 4/2 or 5/2 valves for double-acting cylinders, 3/2 valves for single-acting cylinders, and 2/2 or 3/2 valves for general fluid switching.Pneumatics uses compressed air to transmit energy and signals. Air compressors store energy to drive actuators (e.g., cylinders). While cylinders can reach speeds up to 1 m/s, the optimal operating range is 50–500 mm/s—maximizing economy and minimizing wear and energy use.Recommended solenoid valve port sizes vs. cylinder bore:• φ32–50 mm → 6 mm port• φ40–80 mm → 8 mm port• φ63–125 mm → 10 mm port• φ100–200 mm → 15 mm port• φ160–250 mm → 20 mm port• φ250–400 mm → 25 mm port
