Key Features

✓ DN25 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 11.5 m³/h Flow Capacity

✓ 3/4", 1" or 1¼" BSP

✓ Optional 1½" 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

DN25 3/2 Way Coaxial Solenoid Valve – RSG 37125

The RSG 37125 is a DN25 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 DN25 version provides a Kv flow coefficient of 11.5 m³/h. Standard connections are 3/4", 1" and 1¼" BSP, with an optional 1½" BSP connection available.

Valve Function & Operation

The RSG 37125 is a direct acting 3/2 way coaxial valve available in either normally closed or normally open configurations.

371A25 – 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.

371B25 – 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.

DN25 Ports & Connections

The standard DN25 RSG 37125 is available with:

✓ G3/4 BSP

✓ G1 BSP

✓ G1¼ BSP

Optional connections include:

✓ G1½ BSP

✓ NPT Threads

✓ Flanged Connections

✓ Special Connections

Pressure & Performance

Operating Pressure: 0 to 64 Bar

Reverse Pressure: Up to 16 Bar

Nominal Diameter: DN25

Orifice: 25mm

Kv Flow Coefficient: 11.5 m³/h

Weight – Brass Version: 7.5kg

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 DN25 RSG 37125 provides a Kv flow coefficient of 11.5 m³/h, giving significantly greater flow capacity than the smaller DN10, DN15 and DN20 models while retaining the full 0–64 Bar operating pressure range.

The combination of a 25mm nominal flow path, high pressure capability and zero-differential operation makes the 37125 particularly suitable for demanding industrial fluid and gas control systems.

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 37125 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 makes the configuration particularly useful 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

DN25 power consumption:

24VDC – 77 Watts

230VAC 50Hz – 85 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 initially provides the power required to switch the valve before reducing 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 37125 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 37025, the RSG 37125 increases maximum operating pressure to 64 Bar while retaining the DN25 format and Kv 11.5 m³/h flow capacity.

Available Versions

371A25 – Normally Closed

371B25 – Normally Open

Standard DN25 connections:

✓ 3/4" BSP

✓ 1" BSP

✓ 1¼" BSP

Optional:

✓ 1½" 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

3 Way Coaxial Solenoid Valves

2 Way Coaxial solenoid Valves

3 Way Air Actuated Coaxial Valves

2 Way Air Actuated Valves

3 Way Motor Actuated Valves

View Technical Specification

Technical Specification

Brand: RSG regel-und steuergeräte gmbh

Model: 37125

Width: 90.00 mm

Height: 90.00 mm

Depth: 252.00 mm

Weight: 7.50 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, 11/2 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>500cSt, Water, Water (RO/Pure/Demin)

Orifice: 25mm

Options required: Bi-Directional Flow, Manifold, Manual Override, Mounting Bracket, Mounting Holes, Position Feedback Closed, Position Feedback Open+Closed