Description
DN20 3/2 Way Coaxial Solenoid Valve – RSG 37020
The RSG 37020 is a high-performance DN20 direct acting 3/2 way coaxial solenoid valve designed for reliable directional control of liquids, gases, vacuum and compatible industrial process media from 0 to 40 Bar.
Unlike conventional pilot-operated valves, the RSG 370 Series operates directly from zero pressure without requiring a minimum differential pressure. Its coaxial construction provides reliable switching between the P, A and R ports, making it particularly suitable for pressurising, venting, diverting and switching applications.
The DN20 version provides a Kv flow coefficient of 6.8 m³/h, equivalent to approximately 113 L/min water flow at a 1 Bar pressure differential. Standard connections are 1/2", 3/4" and 1" BSP, with an optional 1¼" BSP connection available. The manufacturer specifies DN20 at 0–40 Bar, Kv 6.8 m³/h and the three standard connections.
Valve Function & Operation
The RSG 37020 is a direct acting 3/2 way coaxial valve available in either normally closed or normally open configurations.
370A20 – Normally Closed
In the de-energised position, pressure supply P is closed while the working port A is connected to return/exhaust R.
When energised, P connects to A and the return connection R is closed.
370B20 – Normally Open
The alternative normally open configuration reverses the switching function.
This 3-port arrangement allows a single coaxial valve to control both pressure supply and exhaust/return functions.
DN20 Ports & Connections
The standard DN20 RSG 37020 is available with:
✓ G1/2 BSP
✓ G3/4 BSP
✓ G1 BSP
Optional connections include:
✓ G1¼ BSP
✓ NPT Threads
✓ Special Connections
Pressure & Performance
Operating Pressure: 0 to 40 Bar
Reverse Pressure: Up to 16 Bar
Nominal Diameter: DN20
Kv Flow Coefficient: 6.8 m³/h
Water Flow: Approx. 113 L/min @ 1 Bar ΔP
Weight – Brass Version: 6.0kg
Flow pressure capability:
P → A: Up to 40 Bar
A → P: Up to 16 Bar
P → R: Up to 40 Bar
R → P: Up to 16 Bar
The manufacturer specifies the 370/371 construction as direct acting, with reverse-pressure leak-tightness up to 16 Bar.
Flow Capacity
The DN20 RSG 37020 has a Kv flow coefficient of 6.8 m³/h, equivalent to approximately 113 L/min water flow at a 1 Bar pressure differential.
The RSG 370 range provides:
DN10 – Kv 2.5 m³/h
DN15 – Kv 4.5 m³/h
DN20 – Kv 6.8 m³/h
DN25 – Kv 11.5 m³/h
DN32 – Kv 17.9 m³/h
DN40 – Kv 34.0 m³/h
DN50 – Kv 42.0 m³/h
DN10 through DN32 operate up to 40 Bar, while DN40 and DN50 operate up to 16 Bar.
3/2 Way Coaxial Valve Design
The RSG 370 Series uses a direct acting coaxial construction with three fluid connections:
✓ P – Pressure / Supply
✓ A – Working / Outlet
✓ R – Return / Exhaust
The actuator operates directly along the fluid flow axis, allowing the valve to switch without relying upon pilot pressure.
The internal construction incorporates a plunger, solenoid, spring and separate 2/2 and 3/2 way valve seat arrangements.
This design is particularly useful for:
✓ Pressure & Exhaust Control
✓ High-Pressure Applications
✓ Industrial Gases
✓ Thick & Glutinous Fluids
✓ Oils & Lubricants
✓ Vacuum Systems
✓ Test & Process Equipment
High Viscosity Fluids
The RSG 37020 can be configured for compatible thick and glutinous fluids with viscosities up to 1000 cSt.
Typical applications can include:
✓ Thick Oils
✓ Hydraulic Oils
✓ Lubricating Oils
✓ Viscous Process Fluids
✓ Glutinous Industrial Liquids
Media compatibility should always be confirmed against the selected body, seat and dynamic sealing materials.
Construction & Materials
Threaded body materials are available in:
✓ Brass
✓ AISI 303 Stainless Steel
✓ AISI 316 Stainless Steel
The manufacturer confirms brass, AISI 303 and AISI 316 as the threaded body materials for the 370/371 Series.
Standard Seal Construction
Static Seal: FKM
Dynamic Seal: PTFE
Valve Seat: FKM
Optional seal configurations include:
✓ NBR
✓ EPDM
✓ PTFE Seat Option
The appropriate body and sealing materials can be selected according to the fluid, gas, temperature and service requirements.
Media Compatibility
Typical applications include:
✓ Water
✓ Hydraulic Oils
✓ Lubricating Oils
✓ Thick Process Fluids
✓ Compressed Air
✓ Industrial Gases
✓ Process Liquids
✓ Cooling Fluids
✓ Compatible Chemicals
For aggressive chemicals or unusual process fluids, compatibility should be confirmed against all wetted materials before ordering.
Special Service Options
The RSG 370 Series can be configured for specialist media and process requirements in addition to standard industrial fluid applications.
Available configurations include:
✓ Water Service Seal Options
✓ Gas Service Seal Options
✓ Oxygen Service Options
✓ Vacuum Service Option
✓ High Leak-Tightness Version
✓ Oil & Grease-Free Construction
Different body materials, seat seals and valve configurations can be selected according to the application and required media compatibility.
For oxygen, vacuum, gas or applications requiring particularly low leakage rates, the required service should be specified when ordering to ensure the correct valve configuration is supplied.
Water Service Seal Option
For demanding water applications, UHMW Polyethylene seals are available with a maximum service temperature of +80°C.
UHMW Polyethylene provides excellent wear resistance and low friction. The dynamic sealing arrangement helps strip limescale and debris from the sealing surface during operation.
This makes the configuration particularly useful where water quality or deposits could reduce the service life of conventional sealing arrangements.
Gas Service Seal Option
For demanding gaseous applications, Fluoroloy® A21 seals are available with a maximum service temperature of +80°C.
Fluoroloy A21 provides low friction, excellent wear characteristics and broad chemical compatibility, making it suitable for appropriately specified industrial gas applications.
Increased Leak-Tightness Version
An increased leak-tightness configuration to 10⁻⁵ mbar·L/sec is available for demanding gas and vacuum applications.
This specialist configuration includes:
✓ Oil & Grease-Free Cleaning
✓ Special Valve Seat Treatment
✓ Special Seal Components
✓ Helium Leak-Tightness Testing
Vacuum Service
A dedicated vacuum configuration is available.
Combined with its direct acting zero-differential design suitable for vacuum equipment requiring controlled switching between pressure, working and return connections.
Oxygen & Clean Service
Oil and grease-free construction is available for specialist clean-service applications, including appropriately specified oxygen-service configurations.
Valves for oxygen service can be supplied degreased and prepared for the application. The required oxygen service, pressure, materials and cleaning specification should be confirmed when ordering.
Temperature
Media Temperature: -10°C to +100°C
Ambient Temperature: -10°C to +50°C
Special Water Seals: Up to +80°C
Special Gas Seals: Up to +80°C
Coil & Electrical Specification
Electrical Duty: 100% ED
Protection: IP65 with connector fitted
Connection: DIN EN 175301-803 Form A
Voltage Tolerance: ±10%
Mounting Position: Any Position
DN20 power consumption:
24VDC – 45 Watts
230VAC 50Hz – 53 Watts
The manufacturer specifies these power ratings for the DN20 RSG 370.
Voltage Options
Standard voltage options include:
✓ 24VDC
✓ 230VAC 50Hz
✓ Special Voltages On Request
For AC operation, the electrical connection incorporates a rectifier.
Additional voltage configurations can be supplied according to application requirements.
Energy Saving PWM Connector Option
The 24VDC version can be fitted with an optional DIN Form A PWM power-reduction connector.
This initially supplies the power required for reliable valve actuation before reducing electrical holding power after the valve has switched.
Potential benefits include:
✓ Up To 80% Lower Holding Power
✓ Lower Coil Temperature
✓ Reduced Energy Consumption
✓ Lower Enclosure Temperature
✓ Extended Solenoid Service Life
✓ Improved Thermal Stability
✓ Ideal For Continuous Duty
Other PWM voltages are available upon request.
Optional Features & Accessories
The RSG 370 Series can be configured with:
✓ Manual Override
✓ Position Indication
✓ LED DIN Connector
✓ Aluminium Terminal Box
✓ Mounting Brackets
✓ PWM Power Reduction Connector
✓ Vacuum Configuration
✓ Oil & Grease-Free Construction
✓ Special Connections
✓ Modular Sub-Base Systems
Position Indication
Optional position indication is available for applications requiring electrical confirmation of valve position.
Open and/or closed position feedback can therefore be incorporated into automated machinery, process control equipment and monitoring systems.
The manufacturer lists position indication as an available electrical option.
Typical Applications
✓ Pressure & Exhaust Control
✓ High Pressure Liquids
✓ High Pressure Gases
✓ Compressed Air Systems
✓ Industrial Gas Systems
✓ Vacuum Systems
✓ Hydraulic Systems
✓ Lubrication Systems
✓ Thick & Glutinous Fluids
✓ Process Engineering
✓ Chemical Processing Equipment
✓ Water Treatment Equipment
✓ Pressure Testing Equipment
✓ Test Rigs & Process Skids
✓ Industrial Automation
✓ OEM Machinery
✓ Manifold Systems
✓ Zero Pressure Applications
Why Choose a 3/2 Way Coaxial Valve?
A 3/2 way valve combines pressure supply, working and return/exhaust functions within a single valve.
The RSG 37020 adds the advantages of direct acting coaxial technology, allowing reliable switching from 0 Bar without relying upon pilot pressure or minimum differential pressure.
Its DN20 construction combines a Kv 6.8 m³/h flow capacity with operation up to 40 Bar, making it particularly suitable for industrial fluid, gas, hydraulic and process-control applications requiring both pressure and exhaust functions.
Available Versions
370A20 – Normally Closed
370B20 – Normally Open
Standard DN20 connections:
✓ 1/2" BSP
✓ 3/4" BSP
✓ 1" BSP
Optional:
✓ 1¼" BSP
Standard voltages:
✓ 24VDC
✓ 230VAC 50Hz Rectified
RSG 3/2 Way Coaxial Valve Ranges
RSG 370 Series – DN10-DN32 up to 40 Bar
RSG 370 Series – DN40-DN50 up to 16 Bar
RSG 371 Series – DN10-DN32 up to 64 Bar
Related Products & Categories
