Model ZW
Round Star ZW series brass solenoid valve, 2/2-way and semi-direct acting so it opens at zero differential pressure. Published G3/8" to G2", 0-10 bar, for water, air, media and light oil to 20 cSt.
Prices on request. Contact us for availability and quotations.
The ZW series is a two-way solenoid valve of semi-direct acting construction. A larger coil lifts the pilot seat and the main diaphragm together, so unlike a purely pilot-operated valve it opens with no differential pressure across it - the reason this pattern is specified on gravity-fed tanks, low head irrigation and pump suction lines where a servo-assisted valve would stay shut.
The body is brass HPb59-1A, with SS304 offered as an alternative, and the standard seal is NBR. Working pressure is 0-10 bar on 220 V AC and 0-6 bar on 24 V DC in the normally closed build, and 0-6 bar in the normally open build; the ceiling is set by the coil pull, not the body, which is why it changes with supply. Fluid temperature is -10 to +80 °C with NBR, and the coil is insulation class H with IP65 protection.
Sizes run G3/8" (ZW-10N) to G2" (ZW-50N) with orifices of 15 to 50 mm and Cv from 3.5 to 48. Both G parallel and NPT threads are catalogued, and seals can be specified NBR, EPDM, FPM (Viton) or VMQ. Low-temperature, encapsulated explosion-proof and IP68 waterproof coils are listed as options.
When ordering, state size, NC or NO, thread form, seal material and coil voltage, and say whether the valve has to open against zero differential - that is the property this series is bought for. Confirm the maximum pressure against the coil supply you intend to use rather than against the series headline figure.
| Type | 2/2-way, semi-direct acting (opens at zero differential pressure), NC or NO |
|---|---|
| Body Material | Brass HPb59-1A; stainless steel SS304 also offered |
| Seal Material | NBR (-10 to +80 °C) standard; EPDM, FPM (Viton) and VMQ optional |
| Size Range | G3/8" to G2" (ZW-10N to ZW-50N); orifice 15, 20, 25, 32, 40 and 50 mm |
| Working Pressure | Varies with coil supply and function, not with size: NC 0-10 bar on AC 220 V and 0-6 bar on DC 24 V; NO 0-6 bar on AC or DC |
| Flow Coefficient (Cv) | 3.5 at G3/8"-G1/2", 7.6 at G3/4", 12 at G1", 24 at G1.1/4", 29 at G1.1/2", 48 at G2" |
| Medium | Water, liquid, media and light oil of viscosity up to 20 cSt |
| Fluid Temperature | -10 to +80 °C with NBR seals |
| Ambient Temperature | -20 to +65 °C |
| Connection | G (parallel) or NPT female thread |
| Coil | AC 220 V, AC 110 V, DC 24 V or DC 12 V. On AC 220 V: 20 VA at DN10-20, 40 VA at DN25, 30 VA at DN32-50. Insulation class H, IP65 plastic coil with terminal box |
| Optional Coils | ES low-temperature; Ex encapsulated explosion-proof (IP65); FS waterproof (IP68) |
