STP21 Direct-Acting Solenoid Valve
Model：STP21-15
Category：STP Pilot Piston Series
The STP21 direct-acting solenoid valve adopts a direct-acting structure where the solenoid coil directly drives the valve core to open and close, operating without relying on medium pressure differential, achieving zero pressure differential start. Port sizes 1/8, 1/4, 3/8 inch, bore DN4-DN10, pressure 0-10bar, suitable for fluid control under small bore, low pressure differential or zero pressure differential conditions.
Technical Parameters
| Bore | DN4-DN10 (1/8, 1/4, 3/8 inch) |
| Working Pressure | 0-10bar (zero pressure differential start) |
| Working Temperature | -5C to 80C |
| Valve Body Material | Brass / Stainless Steel |
| Voltage | AC220V / DC24V |
| Seal Material | NBR / EPDM / PTFE |
| Action Mode | Normally Closed / Normally Open (optional) |
| Connection | Internal Thread |
Product Features
- Zero pressure differential start: operates without medium pressure differential, suitable for vacuum and low pressure conditions
- Direct-acting structure: extremely fast response, reliable operation
- Small bore design: suitable for precision flow control
- Simple structure, easy maintenance
- Normally closed / normally open types available
- Material options: brass or stainless steel
Selection & Installation Guide
- For zero or low pressure differential conditions, direct-acting type is preferred
- Select port size based on flow requirements (1/8, 1/4, 3/8 inch)
- For large bore and high flow conditions, pilot-operated type is recommended
- Install with valve body arrow aligned with fluid flow direction
- Install coil vertically upward to avoid liquid accumulation
- When medium contains impurities, install a filter before the valve
- Keep voltage fluctuation within +/-10%