Pressure Reducing Valves
The pressure reducing valves in this group are used on steam, compressed air and neutral gas lines; they reduce a high and fluctuating inlet pressure to a constant, set outlet pressure on the line feeding the consumer. Threaded direct-acting bellows types are available for small consumers and flanged types for main distribution lines.
In direct-acting bellows types the outlet pressure is balanced on the bellows against a setting spring; setting is made with the adjusting handwheel in three spring ranges between 0.14 and 8.6 bar, and the valve body contains a stainless strainer. They are preferred where precise setting is not required, on 1/2″–1″ supplies to heaters, presses, irons and small process equipment.
Main Applications
- Steam irons, presses and small heater supplies
- Laboratory and kitchen steam equipment
- Pressure limiting at compressed air points of use
- Low-pressure steam branches leaving the boiler room
- Pressure reduction on neutral gas lines
Technical Data
| Operating principle | Direct acting; bellows and setting spring (threaded type) |
|---|---|
| Connection (threaded) | 1/2″, 3/4″, 1″ BSP or NPT |
| Body pressure class | PN25 |
| Max. inlet pressure | 19 bar |
| Max. outlet pressure | 8.6 bar |
| Setting ranges | 0.14–1.70 · 1.40–4.00 · 3.50–8.60 bar |
| Max. temperature | 210 °C |
| Recommended max. reduction ratio | 10:1 (at max. flow) |
| Dimensions (threaded) | Height 186.5 mm · length 83 / 96 / 108 mm (1/2″ / 3/4″ / 1″) |
| Installation | Horizontal line, following the arrow on the body |
| Flanged types | DN15–DN150, PN16–PN40, EN 558 Series 1 length, EN 1092 flanges |
| Flanged type tightness | Class I (DIN EN 1349; ≤ 0.05% of Kvs) |
Material Options
| Part | PN25 · ductile iron, threaded direct acting | PN16 · grey iron, flanged | PN40 · cast steel, flanged |
|---|---|---|---|
| Body | Ductile iron GGG40.3 | Grey iron EN-GJL-250 | Cast steel GP240GH+N (1.0619+N) |
| Seat | Stainless AISI 431 | Stainless 1.4021+QT | Stainless 1.4021+QT |
| Plug / valve | Stainless AISI 420 | Stainless 1.4021+QT, hardened | Stainless 1.4021+QT, hardened |
| Bellows | Stainless AISI 316 | Stainless bellows unit (depending on model) | Stainless bellows unit (depending on model) |
| Setting spring | Stainless steel | 51CrV4 (1.8159) | 51CrV4 (1.8159) |
| Strainer | Stainless AISI 316 | — | — |
| Bonnet gasket | Graphite | Pure graphite (CrNi laminated) | Pure graphite (CrNi laminated) |
| Bonnet | Aluminium upper cover | Ductile iron EN-GJS-400-18U-LT | Ductile iron EN-GJS-400-18U-LT |
Which type? On lines of 1″ and below, where precise outlet pressure setting is not required, the threaded direct-acting type is the economical solution; inlet pressure must not exceed 19 bar and outlet 8.6 bar. On high-flow main lines and for precise pressure setting, flanged diaphragm-actuated types are selected. Placing a steam separator ahead of the valve to remove moisture extends plug life.
Advantages
No Auxiliary Energy
- Works with line pressure and spring force.
- No electricity or compressed air needed.
Built-in Strainer
- Stainless strainer inside the body.
- Protects the seat from dirt and weld debris.
Three Setting Ranges
- From 0.14 up to 8.6 bar.
- The spring is chosen to suit the consumer pressure.
Compact Body
- 83–108 mm length, 186.5 mm height.
- Fits in a small space next to equipment.
Stainless Internals
- Bellows, plug and seat in stainless steel.
- Long life in steam and humid air.
Construction and Design Features
- Threaded ductile iron body and aluminium upper cover
- Stainless bellows sensing the outlet pressure
- Adjusting handwheel and setting stem with lock pin
- AISI 420 plug and AISI 431 seat
- Graphite bonnet gasket and stainless strainer inside the body
Send the inlet and required outlet pressure, the flow (kg/h or Nm³/h) and the connection size through the Request a Quote form; we will determine the right size and spring range from the capacity chart.
How to Choose?
- Define the pressuresNote the maximum inlet and required outlet pressure; the ratio should not exceed 10:1.
- Calculate the flowDetermine the steam (kg/h) or air demand of the consumer.
- Pick the size from the chartRead the size at the point where the outlet pressure meets the inlet curve on the capacity chart.
- Choose the spring rangeSelect the spring range that covers the outlet pressure.
- Plan the installationOn a horizontal line, fit an isolating valve and condensate drain upstream and a pressure gauge and safety valve downstream.
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Why ORFA?
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Details →Our Pressure Reducing Valves
ORFA supplies pressure reducing valves in a range of pressure classes, sizes and connection types to suit your application. Descriptions, technical specifications, materials and dimension tables are available on each detail page.
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