Key Differences Between Solenoid Valves
Here’s Ekgas a clear and helpful explanation of Solenoid Valve Differences — focusing on the most common ways solenoid valves differ: by operation method, function, power type, structure, and application.
🔍 Key Differences Between Solenoid Valves
1️⃣ Operating Principle
| Type | How it Works | Features | Applications |
|---|---|---|---|
| Direct-Acting | Coil directly lifts the valve plunger to open/close flow | Works at zero pressure, fast response | Small systems, low flow, vacuum |
| Pilot-Operated | Uses system pressure and pilot hole for operation | Requires minimum pressure, larger flow | HVAC, water systems, industrial pipelines |
| Semi-Direct | Combination of both types | Can work at low pressure, more flow | Versatile, better performance |
2️⃣ Function (Flow Control)
| Function | Description | Usage |
|---|---|---|
| 2-Way | Open or close fluid flow | On/off control (air, water, gas) |
| 3-Way | Switch between two outlets or exhaust | Pneumatic actuator control |
| 4-Way | Controls double-acting cylinders | Automation and pneumatic system direction |
3️⃣ Power Supply Differences
| Power Type | Features | Pros | Cons |
|---|---|---|---|
| DC (12V/24V) | Stable, lower heat | Safe, battery-friendly | Slower response |
| AC (110V/220V) | Strong magnetic force | Faster action | Generates heat & noise |
4️⃣ Normally Open (NO) vs Normally Closed (NC)
| Type | Status Without Power | Common Use |
|---|---|---|
| Normally Closed (NC) | Valve closed | Most common, safe shutdown |
| Normally Open (NO) | Valve open | Cooling, venting, continuous flow |
5️⃣ Body Material
| Material | Features | Application |
|---|---|---|
| Brass | Affordable, good durability | Air, water, oil |
| Stainless Steel (SS304/316) | Corrosion resistant | Food, gas, chemical |
| Plastic (PVC/PTFE) | Chemical resistance | Corrosive fluids, low pressure |
| Cast Iron | Strong but heavy | High-flow industrial |
6️⃣ Sealing Material (Media Compatibility)
| Seal Type | Features | Suitable Media |
|---|---|---|
| NBR | Oil resistant | Air, oil, gas |
| EPDM | Heat/water resistant | Hot water, steam |
| Viton | Chemical & heat resistant | Acid, chemical gas |
| PTFE | High chemical resistance | Aggressive chemical fluids |
7️⃣ Application Differences
| Industry | Typical Solenoid Valve |
|---|---|
| Water Treatment | Pilot-operated, stainless steel |
| Pneumatics | 3-way or 5-way, direct-acting |
| Gas Systems | Explosion-proof solenoid valve |
| Medical | Small DC low-power valve |
| HVAC | Normally closed water control valve |
📝 Summary Table
| Category | Main Options |
|---|---|
| Operation | Direct, Semi-Direct, Pilot |
| Function | 2-way, 3-way, 4-way |
| Power Type | AC, DC |
| Default State | Normally Open, Normally Closed |
| Body | Brass, SS, Plastic |
| Seal | NBR, EPDM, Viton, PTFE |
| Application | Water, Gas, Chemical, Pneumatic |
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