Key Features
✓ DN25 Coaxial Solenoid Valve
✓ 2/2 Way Normally Closed
✓ Normally Open Version Available
✓ Direct Acting Operation
✓ Zero Differential Pressure
✓ 0–64 Bar Operating Pressure
✓ 16 Bar Reverse Pressure
✓ Kv 12.3 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
✓ TÜV & DVGW Approved
✓ Vacuum Service Option
✓ Oxygen Service Options
✓ Oil & Grease-Free Option
✓ Manual Override Option
✓ Free UK Delivery Available
Datasheets
Description
DN25 Coaxial Solenoid Valve 0-64 Bar – RSG 27125
The RSG 27125 is a high-pressure DN25 direct acting coaxial solenoid valve designed for reliable control of liquids, oils, gases, vacuum and compatible industrial process media from 0 to 64 Bar. Its pressure-balanced coaxial construction requires no minimum differential pressure, providing dependable switching from zero pressure through to demanding high-pressure applications.
Unlike conventional pilot-operated diaphragm valves, the RSG 271 Series uses a coaxial plunger arrangement with the actuator positioned around the fluid flow path. This design is particularly suited to high-pressure industrial systems, test equipment, gases, oils and thick or glutinous process fluids with viscosities up to 1000 cSt.
The DN25 version provides a substantial increase in flow capacity compared with the smaller models, with a Kv flow coefficient of 12.3 m³/h and standard 3/4", 1" or 1¼" BSP connections, plus an optional 1½" connection. Operating pressure is 0–64 Bar with reverse pressure capability up to 16 Bar.
Valve Function & Operation
The RSG 27125 is a 2/2 way direct acting coaxial valve available in either normally closed or normally open configurations.
271A25 – Normally Closed
The valve remains closed without electrical power and opens when the solenoid is energised.
271B25 – 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 minimum pressure differential across the valve. This provides reliable switching from 0 Bar through to 64 Bar.
DN25 Ports & Connections
The standard DN25 RSG 27125 is available with:
✓ G3/4 BSP
✓ G1 BSP
✓ G1¼ BSP
Optional connections include:
✓ G1½ BSP
✓ NPT Threads
✓ PN16 Flanges
✓ PN40 Flanges
✓ PN100 Flanges
This provides considerable installation flexibility for both threaded pipework and high-pressure industrial process systems.
Pressure & Performance
Operating Pressure: 0 to 64 Bar
Reverse Flow Pressure: Up to 16 Bar
Nominal Diameter: DN25
Kv Flow Coefficient: 12.3 m³/h
Water Flow: Approx. 205 L/min @ 1 Bar ΔP
Weight – Brass Version: 7.1kg
The RSG 27125 combines true zero-pressure direct acting operation with high flow capacity and substantially greater pressure capability than the corresponding RSG 269 and RSG 270 DN25 valves.
Flow Capacity
The DN25 valve has a Kv flow coefficient of 12.3 m³/h, equivalent to approximately 205 L/min water flow at a 1 Bar pressure differential.
The RSG 271 range provides:
DN10 – Kv 2.5 m³/h
DN15 – Kv 5.2 m³/h
DN20 – Kv 7.0 m³/h
DN25 – Kv 12.3 m³/h
DN32 – Kv 20.0 m³/h
Coaxial Valve Design
The RSG 271 Series uses a coaxial construction, with the solenoid surrounding the central plunger and fluid flow path.
The actuator force acts directly along the same axis as the fluid flow, allowing operation independently of minimum differential pressure.
This design is particularly useful for:
✓ Zero-Pressure Applications
✓ High-Pressure Applications
✓ High-Pressure Gases
✓ Thick & Glutinous Fluids
✓ Oils & Lubricants
✓ High-Flow Process Systems
✓ Test & Process Equipment
High Viscosity Fluids
The RSG 27125 is suitable for thick and glutinous fluids with viscosities up to 1000 cSt.
This makes the coaxial design particularly useful for applications involving:
✓ Thick Oils
✓ Hydraulic Oils
✓ Lubricating Oils
✓ Viscous Process Fluids
✓ Glutinous Industrial Liquids
The direct acting coaxial construction avoids reliance on the small pilot passages used by conventional servo-operated diaphragm valves, making it particularly useful where thicker media can create operational problems for conventional valve designs.
Construction & Materials
Threaded body materials are available in:
✓ Brass
✓ AISI 303 Stainless Steel
✓ AISI 316 Stainless Steel
Flanged versions can also be supplied in alternative materials according to the connection and application requirements.
Standard Seal Construction
Static Seal: FKM
Dynamic Seals: PTFE
Valve Seat: FKM or PTFE
Optional seal configurations include:
✓ NBR
✓ EPDM
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 271 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
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 plug fitted
Connection: DIN EN 175301-803 Form A
Voltage Tolerance: ±10%
Mounting Position: Any Position
DN25 power consumption:
24VDC – 77 Watts
230VAC 50Hz – 85 Watts
Voltage Options
Standard voltage options include:
✓ 24VDC
✓ 230VAC 50Hz
✓ Special Voltages On Request
For AC operation, the electrical connector incorporates a rectifier.
Additional electrical 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 the 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 271 Series can be configured with:
✓ Manual Override
✓ E1 Position Indication
✓ E2 Position Indication
✓ Inductive Position Switches
✓ LED 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.
E1 – Single Position Indication
E2 – Double Position Indication
Open and/or closed position monitoring can therefore be incorporated into automated machinery, process control systems and safety monitoring circuits.
Typical Applications
✓ High Pressure Liquids
✓ High Pressure Gases
✓ Pressure Testing Equipment
✓ Test Rigs & Process Skids
✓ Hydraulic Systems
✓ Lubrication Systems
✓ Thick & Glutinous Fluids
✓ Compressed Air Systems
✓ Industrial Gas Systems
✓ Vacuum Systems
✓ Process Engineering
✓ Industrial Automation
✓ Water Treatment Equipment
✓ Chemical Processing Equipment
✓ Laboratory Equipment
✓ OEM Machinery
✓ Zero 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 zero-pressure systems, closed-loop circuits and applications where pressure can equalise across the valve.
The RSG 27125 is direct acting from 0 Bar, so switching does not depend upon pressure differential.
Its DN25 coaxial construction combines a substantial Kv 12.3 m³/h flow capacity with operating pressure up to 64 Bar, making it particularly suitable for high-pressure machinery, gas systems, process equipment and test applications where both high flow and pressure capability are important.
Available Versions
271A25 – Normally Closed
271B25 – Normally Open
Standard DN25 connections:
✓ 3/4" BSP
✓ 1" BSP
✓ 1¼" BSP
Optional:
✓ 1½" BSP
Standard voltages:
✓ 24VDC
✓ 230VAC 50Hz Rectified
RSG Coaxial Valve Pressure Ranges
RSG 269 Series – up to 20 Bar
RSG 270 Series – up to 40 Bar
RSG 271 Series – up to 64 Bar
RSG 272 Series – up to 100 Bar
The RSG 271 Series bridges the gap between the 40 Bar RSG 270 and 100 Bar RSG 272 ranges, providing direct acting coaxial valve operation from zero pressure through to 64 Bar.
Related Products & Categories
Technical Specification
Brand: RSG regel-und steuergeräte gmbh
Model: 27125
Width: 90.00 mm
Height: 133.50 mm
Depth: 246.00 mm
Weight: 8.00 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, 11/2 thread, 11/4 thread, 3/4 thread
Function: 2/2 Failsafe Closed, 2/2 Failsafe Open
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
Found in these Categories
- 3/4 Brass Solenoid Valves
- 1 Brass Solenoid Valves
- 1¼ Brass Solenoid Valves
- 1½ Brass Solenoid Valves
- 11/4" Stainless solenoid valves
- 11/2" Stainless solenoid valves
- Stainless Steel 2/2 Normally Open 0 Bar Solenoid Valves
- Air Solenoid Valves
- Water Solenoid Valves
- Light Oil Solenoid Valves
- Viscous Liquid Solenoid Valves
- Acid & Alkali Solenoid Valves
- Fuel Solenoid Valves
- 3/4 Inch Solenoid Valves
- 1 Solenoid Valves
- 11/4 Solenoid Valves
- 11/2 Solenoid Valves
- 40 Bar Solenoid Valves
- Coaxial Solenoid Valves - 2/2 Way
- 2/2 Normally Closed Solenoid Valves
- 2/2 Normally Open Solenoid Valves
- 11/4 High Pressure Solenoid Valves to 160 Bar
- 11/2 High Pressure Solenoid Valves to 200 Bar
- 3/4 High Pressure Solenoid Valves to 400 Bar
- 1 High Pressure Solenoid Valves to 400 Bar
- 2/2 Normally Closed - Zero Rated
- 2/2 Normally Open - Zero Rated
- 50–600 Bar High Pressure Solenoid Valves
- Coaxial Solenoid Valves 2/2 0-64 Bar
- Coaxial Solenoid Valves
Coax solenoid valve 2/2 64Bar Brass Stainless 3/4-11/2 DN25
£702.77 incl. VAT £585.64 ex. VAT
-57% Was £1,648.14 incl. VAT