Key Features
- DN20 3/2 Way Coaxial Valve
- Normally Closed Operation
- Normally Open Version Available
- Direct Acting Operation
- Zero Differential Pressure
- 0–64 Bar Operating Pressure
- 16 Bar Reverse Pressure
- Kv 6.8 m³/h Flow Capacity
- 1/2", 3/4" or 1" BSP
- Optional 1¼" BSP Connection
- Brass or Stainless Steel Body
- FKM & PTFE Seals
- Fluids Up To 1000 cSt
- -10°C to +100°C Media
- 24VDC or 230VAC
- IP65 With Connector Fitted
- Vacuum Service Option
- High Leak-Tightness Option
- Oil & Grease-Free Option
- Manual Override Option
- Position Indication Option
- Free UK Delivery Available
Datasheets
Description
DN20 3/2 Way Coaxial Solenoid Valve – RSG 37120
The RSG 37120 is a 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 64 Bar.
Unlike conventional pilot-operated valves, the RSG 371 Series operates directly from zero pressure without requiring a minimum differential pressure. Its coaxial construction provides positive switching between the P, A and R ports, making it particularly suitable for high-pressure pressurising, venting, diverting and switching applications.
The DN20 version provides a Kv flow coefficient of 6.8 m³/h. Standard connections are 1/2", 3/4" and 1" BSP, with an optional 1¼" BSP connection available.
Valve Function & Operation
The RSG 37120 is a direct acting 3/2 way coaxial valve available in either normally closed or normally open configurations.
371A20 – 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.
371B20 – Normally Open
The alternative normally open configuration reverses the switching function.
This 3-port arrangement allows a single valve to control both pressure supply and exhaust/return functions.
DN20 Ports & Connections
The standard DN20 RSG 37120 is available with:
✓ G1/2 BSP
✓ G3/4 BSP
✓ G1 BSP
Optional connections include:
✓ G1¼ BSP
✓ NPT Threads
✓ Flanged Connections
✓ Special Connections
Pressure & Performance
Operating Pressure: 0 to 64 Bar
Reverse Pressure: Up to 16 Bar
Nominal Diameter: DN20
Orifice: 20mm
Kv Flow Coefficient: 6.8 m³/h
Weight – Brass Version: 6.0kg
Flow pressure capability:
P → A: Up to 64 Bar
A → P: Up to 16 Bar
P → R: Up to 64 Bar
R → P: Up to 16 Bar
The direct acting construction allows reliable operation from 0 Bar without requiring a minimum pressure differential.
Flow Capacity
The DN20 RSG 37120 provides a Kv flow coefficient of 6.8 m³/h, giving substantially increased flow capacity over the smaller DN10 and DN15 models while retaining the full 0–64 Bar operating pressure range.
This makes the DN20 version particularly useful for applications requiring a combination of high pressure, unrestricted zero-differential operation and relatively high flow through a compact 3/2 way valve.
3/2 Way Coaxial Valve Design
The RSG 371 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.
This construction provides fast, positive switching and 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 37120 is suitable 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 and sealing materials.
Construction & Materials
Body materials are available in:
✓ Brass
✓ AISI 303 Stainless Steel
✓ AISI 316L Stainless Steel
Internal Components: Stainless Steel 316L
The choice of body material allows the valve to be configured for a wide range of demanding industrial liquid, gas and process applications.
Standard Seal Construction
Fluid sealing materials include:
✓ FKM
✓ PTFE
Optional seal configurations include:
✓ NBR
✓ EPDM
The appropriate sealing materials can be selected according to media, temperature and application requirements.
Media Compatibility
Typical applications include:
✓ Water
✓ Hydraulic Oils
✓ Lubricating Oils
✓ Thick Process Fluids
✓ Compressed Air
✓ Industrial Gases
✓ Process Liquids
✓ Cooling Fluids
✓ Compatible Chemicals
✓ Viscous Fluids Up To 1000 cSt
For aggressive chemicals or unusual process fluids, compatibility should be confirmed against all wetted materials before ordering.
Special Service Options
The RSG 371 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
✓ Vacuum Service Option
✓ Oil & Grease-Free Construction
Different body materials, sealing arrangements and valve configurations can be selected according to the application and required media compatibility.
For vacuum, gas or specialist applications, 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 and abrasion resistance together with very good lubricity in water-based media.
The special sharp-edged shape of the dynamic seal creates a stripping action against the piston/plunger, helping remove limescale and debris during operation.
This can provide an advantage in water systems where deposits or contamination could affect 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 excellent wear resistance, low friction and broad chemical compatibility, together with high sealing performance for appropriately specified gaseous media.
Temperature
Media Temperature: -10°C to +100°C
Ambient Temperature: -10°C to +50°C
Water Seal Option: Up to +80°C
Gas Seal Option: Up to +80°C
Coil & Electrical Specification
Electrical Duty: 100% ED
Protection: IP65 with connector fitted
Connection: DIN 43650A
Mounting Position: Any Position
DN20 power consumption:
24VDC – 53 Watts
230VAC 50Hz – 59 Watts
Voltage Options
Available voltage configurations include:
✓ 12VDC
✓ 24VDC
✓ 24VAC
✓ 110VAC
✓ 230VAC
✓ Other Voltages On Request
AC versions use an appropriate rectified electrical configuration.
Energy Saving PWM Connector Option
The 24VDC valve can be fitted with an optional PWM power-reduction connector.
The connector provides the initial power required to switch the valve before reducing the electrical holding power once the valve is energised.
Potential benefits include:
✓ Up To 80% Lower Holding Power
✓ Lower Coil Temperature
✓ Reduced Energy Consumption
✓ Lower Heat Emission
✓ Improved Thermal Stability
✓ Extended Solenoid Service Life
✓ Ideal For Continuous Duty
PWM technology is also available for other voltages upon request.
Optional Features & Accessories
The RSG 371 Series can be configured with:
✓ Manual Override
✓ Open Position Feedback
✓ Closed Position Feedback
✓ Volt-Free Feedback Switches
✓ Various DIN Connectors
✓ Aluminium Terminal Box
✓ Mounting Brackets
✓ PWM Power Reduction Connector
✓ Vacuum Configuration
✓ Oil & Grease-Free Construction
✓ NPT Connections
✓ Flanged Connections
Position Indication
Optional volt-free position feedback switches can provide electrical confirmation of the valve's open and/or closed position.
This allows valve status to be incorporated into PLC systems, industrial automation, safety monitoring and process-control equipment.
Typical Applications
✓ High-Pressure Fluid Control
✓ Pressure & Exhaust Control
✓ High-Pressure Gas Systems
✓ Hydraulic Systems
✓ Compressed Air Systems
✓ Industrial Gas Systems
✓ Vacuum Systems
✓ Lubrication Systems
✓ Thick & Glutinous Fluids
✓ Viscous Process Fluids
✓ Process Engineering
✓ Chemical Processing Equipment
✓ Pressure Testing Equipment
✓ Test Rigs & Process Skids
✓ Industrial Automation
✓ OEM Machinery
✓ Manifold Systems
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 37120 combines this functionality with direct acting coaxial technology, allowing reliable switching from 0 Bar without relying upon pilot pressure or minimum differential pressure.
Compared with the 40 Bar RSG 37020, the RSG 37120 increases maximum operating pressure to 64 Bar while retaining the DN20 format and Kv 6.8 m³/h flow capacity.
Available Versions
371A20 – Normally Closed
371B20 – Normally Open
Standard DN20 connections:
✓ 1/2" BSP
✓ 3/4" BSP
✓ 1" BSP
Optional:
✓ 1¼" BSP
✓ NPT
✓ Flanged Connections
Standard and optional voltages:
✓ 12VDC
✓ 24VDC
✓ 24VAC
✓ 110VAC
✓ 230VAC
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
Technical Specification
Brand: RSG regel-und steuergeräte gmbh
Model: 37120
Width: 80.00 mm
Height: 80.00 mm
Depth: 228.00 mm
Weight: 6.00 kg
Valve / Product Type: Coaxial Valve, Solenoid Valve
Body Material: Brass, Stainless Steel
Voltage: 110vAC, 110vDC, 12vAC, 12vDC, 200vDC, 230VAC, 24vAC, 24vDC, 48vAC, 48vDC
Port Size: 1 thread, 1/2 thread, 11/4 thread, 3/4 thread
Function: 3/2 Normally Closed, 3/2 Normally Open, 3/2 Universal
Operation: Direct Acting
Pressure: 50 Bar, 60 Bar, 64 Bar
Seals: EPDM, NBR, PTFE (Teflon), FKM (Viton)
Approvals:: IP65
Media: Air, Fluid (Non Aggressive), Fluid (Slight Acid/Alkali), Gases (Non Aggressive), Oils + Fuels 50cSt Max, Fluid Thick 51>1000cSt, Water, Water (RO/Pure/Demin)
Orifice: 20mm
Options required: Bi-Directional Flow, Manifold, Manual Override, Mounting Bracket, Mounting Holes, Position Feedback Closed, Position Feedback Open+Closed
Found in these Categories
- 1/2 Brass Solenoid Valves
- 3/4 Brass Solenoid Valves
- 1 Brass Solenoid Valves
- Brass Solenoid Valves - 3/2 Way
- 3/4" Stainless Steel Solenoid Valves
- 1" Stainless Steel Solenoid Valves
- Stainless 3/2 Way
- Air Solenoid Valves
- Water Solenoid Valves
- Light Oil Solenoid Valves
- Viscous Liquid Solenoid Valves
- Acid & Alkali Solenoid Valves
- Fuel Solenoid Valves
- 1/2 Inch Solenoid Valves
- 3/4 Inch Solenoid Valves
- 1 Solenoid Valves
- 40 Bar Solenoid Valves
- Coaxial Solenoid Valves - 3/2 Way
- 3/2 Way Solenoid Valves
- 1 High Pressure Solenoid Valves to 400 Bar
- 11/4 High Pressure Solenoid Valves to 160 Bar
- 3/4 High Pressure Solenoid Valves to 400 Bar
- 1/2 High Pressure Solenoid Valves to 400 Bar
- 50–600 Bar High Pressure Solenoid Valves
- Coaxial Solenoid Valves 3/2 0-64 Bar
- 90° Outlet
Coax solenoid valve 3/2 64 Bar Brass Stainless 1/2-11/4 DN20
£643.63 incl. VAT £536.36 ex. VAT
-57% Was £1,509.47 incl. VAT