Description
DN20 Coaxial Solenoid Valve 0-20 Bar – RSG 26920
The RSG 26920 is a compact DN20 direct acting coaxial solenoid valve designed for reliable control of liquids, oils and compatible industrial process fluids from 0 to 20 Bar. Its pressure-balanced coaxial construction eliminates the need for a minimum differential pressure, providing dependable switching even from zero pressure.
Unlike conventional pilot-operated diaphragm valves, the RSG 269 Series uses a coaxial plunger arrangement with the actuator positioned around the flow path. This robust design provides rapid switching, low mechanical wear and reliable operation with demanding process media.
The DN20 version offers a Kv flow coefficient of 7.0 m³/h with 1/2", 3/4" or 1" BSP connections. The manufacturer specifies 0–20 Bar in the normal P→A direction and back-pressure sealing up to 12 Bar in the reverse A→P direction.
Valve Function & Operation
The RSG 26920 is a 2/2 way direct acting coaxial valve available in either normally closed or normally open configurations.
269A20 – Normally Closed
The valve remains closed without electrical power and opens when the solenoid is energised.
269B20 – Normally Open
The valve remains open without electrical power and closes when energised.
Because the valve is direct acting, operation does not depend upon inlet pressure or a pressure differential across the valve. This allows reliable switching from 0 Bar, making the 26920 particularly useful where conventional pressure-assisted solenoid valves cannot operate reliably.
DN20 Ports & Connections
The standard DN20 RSG 26920 is available with:
✓ G1/2 BSP
✓ G3/4 BSP
✓ G1 BSP
✓ G1¼ BSP Option
This allows the same DN20 valve mechanism to be selected with the connection size most appropriate for the installation.
Pressure & Performance
Operating Pressure: 0 to 20 Bar
Forward Flow P→A: Maximum 20 Bar
Reverse Flow A→P: Maximum 12 Bar
Nominal Diameter: DN20
Kv Flow Coefficient: 7.0 m³/h
The coaxial design therefore provides full operation from zero pressure while also allowing reverse pressure applications within the manufacturer's specified 12 Bar limit.
Flow Capacity
The DN20 valve has a manufacturer-specified Kv of 7.0 m³/h.
The other 269 Series models provide:
DN10 – Kv 2.5 m³/h
DN15 – Kv 5.2 m³/h
DN25 – Kv 12.3 m³/h
Coaxial Valve Design
The RSG 269 Series uses a characteristic coaxial construction, with the solenoid surrounding the central plunger and fluid path.
The principal internal components comprise the adapter fittings, valve seat, plunger, solenoid, spring and twin PTFE rod seals. This arrangement allows the actuator force to act directly along the same axis as the fluid flow.
This design is particularly useful for:
✓ Zero-pressure applications
✓ High switching reliability
✓ Compact machinery installations
✓ Difficult industrial fluids
✓ Bidirectional pressure duties
✓ Frequent switching applications
✓ Thick glutinous fluids up to 1000cst
Construction & Materials
Body / Adapter Material: Brass
Static Seal: FKM
Dynamic Seals: PTFE
Valve Seat Seal: FKM
The combination of brass, FKM and PTFE provides good compatibility with a broad range of industrial liquids and oils, subject to chemical compatibility with all wetted materials.
Media Compatibility
Typical compatible applications include:
✓ Water
✓ Hydraulic oils
✓ Lubricating oils
✓ Process liquids
✓ Cooling fluids
✓ Compatible chemicals
✓ Industrial liquids
For aggressive chemicals or unusual process fluids, compatibility should be confirmed against the brass, FKM and PTFE wetted materials before ordering.
Temperature
Media Temperature: -10°C to +100°C
Ambient Temperature: -10°C to +50°C
Coil & Electrical Specification
Electrical Duty: 100% ED
Protection: IP65 with plug fitted
Connection: DIN EN 175301-803 Form A
Voltage Tolerance: ±10%
Mounting Position: Any Position
The ability to install the valve in any mounting position provides considerably more flexibility than conventional solenoid valves that normally require the operator to be mounted vertically.
Voltage Options
Standard manufacturer voltage options are:
✓ 24VDC
✓ 230VAC 50Hz
✓ Other voltages available on request
For AC operation, the DIN connector incorporates a rectifier for operation of the solenoid.
The DN20 power consumption is:
24VDC – 34 Watts
230VAC 50Hz – 42 Watts
Energy Saving Connector Option
The 24VDC version can be specified with an optional DIN Form A power-reduction connector.
This initially supplies the power required for reliable valve actuation and then reduces the electrical holding power after switching.
Potential benefits include:
✓ Reduced Holding Power
✓ Lower Coil Temperature
✓ Reduced Energy Consumption
✓ Lower Enclosure Temperature
✓ Extended Solenoid Service Life
✓ Ideal For Continuous Duty
Optional Accessories
The RSG 269 Series can also be configured with:
✓ Mounting Bracket
✓ LED DIN Connector
✓ Power Reduction Connector
✓ Special Thread Connection
✓ M12x1 Electrical Connector
The DN20 mounting bracket is available as mechanical option 15, while special connections are mechanical option 07.
Typical Applications
✓ Hydraulic Systems
✓ Lubrication Systems
✓ Process Engineering
✓ Industrial Automation
✓ Cooling Systems
✓ Water Treatment Equipment
✓ Chemical Processing Equipment
✓ Machine Tool Systems
✓ OEM Machinery
✓ Test & Measurement Equipment
✓ Zero Pressure Applications
✓ Reverse Pressure Applications
Why Choose a Coaxial Valve?
A conventional pilot-operated solenoid valve requires sufficient pressure differential to lift its diaphragm or piston. This can make it unsuitable for low-pressure systems, closed-loop circuits and applications where pressure can equalise across the valve.
The RSG 26920 is direct acting from 0 Bar, so switching does not depend upon pressure differential.
Its coaxial construction also provides a compact and mechanically robust solution for industrial applications requiring reliable switching, high cycle capability and flexible mounting.
Available Versions
269A20 – Normally Closed
269B20 – Normally Open
Standard DN20 connections:
✓ 1/2" BSP
✓ 3/4" BSP
✓ 1" BSP
Standard voltages:
✓ 24VDC
✓ 230VAC 50Hz Rectified
Higher Pressure Coaxial Valves
For applications requiring pressures above 20 Bar, alternative RSG coaxial valve ranges are available:
RSG 270 Series – up to 40 Bar
RSG 271 Series – up to 64 Bar
RSG 272 Series – up to 100 Bar
These provide additional options for demanding hydraulic, lubrication and process applications where a direct acting coaxial valve is preferred.
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