Flanged Piston Valves
A flanged piston valve is a globe-pattern shut-off valve bolted into the pipeline through flanges drilled to EN 1092-2 at both ends; instead of a disc, a stainless piston sliding between two graphite rings does the closing. The flanged connection lets the valve be taken out of the line and refitted without welding or threading.
Grey iron PN16 versions are made from DN15 to DN100 and ductile iron PN40 versions from DN15 to DN50; the ductile iron PN16 series extends to DN200. Face-to-face lengths follow EN 558 Series 1, so the valve replaces a standard globe valve of the same size without changing the pipe length.
Main Applications
- Boiler room steam header outlets
- Superheated water and hot water distribution lines
- Shut-off points at heat exchanger inlets and outlets
- Compressed air main lines
- Service valve on condensate return lines
Technical Data
| Connection | Flanged, EN 1092-2 |
|---|---|
| Face-to-face | EN 558 Series 1 (DN15 130 mm … DN100 350 mm) |
| Size and pressure | PN16: DN15–DN200 · PN40: DN15–DN50 |
| Body | Grey iron EN-GJL-250 (PN16) · ductile iron (PN16, PN40) |
| Temperature – PN16 grey iron | −10 / +300 °C |
| Temperature – PN40 ductile iron | −20 / +350 °C |
| Pressure–temperature (PN16 grey) | 16 bar / 120 °C · 9.6 bar / 300 °C |
| Pressure–temperature (PN40 ductile) | 40 bar / 120 °C · 28 bar / 350 °C |
| Kv value | 4.5 m³/h (DN15) … 165 m³/h (DN100) · 590 m³/h (DN200) |
| Flange holes (PN16) | 4 holes DN15–DN65 · 8 holes DN80–DN150 |
| Weight (PN16 grey) | 3.0 kg (DN15) … 41.2 kg (DN100) |
| Ring temperature limit | Metal-reinforced graphite ring: up to 550 °C (body limit applies) |
Material Options
| Part | PN16 · grey iron body | PN16 · ductile iron body | PN40 · ductile iron body |
|---|---|---|---|
| Body | Grey iron EN-GJL-250 (5.1301) | Ductile iron GGG40 (EN-GJS-400) | Ductile iron EN-GJS-400-18-LT (5.3103) |
| Bonnet | Grey iron EN-GJL-250 (5.1301) | Ductile iron GGG40 (EN-GJS-400) | Ductile iron EN-GJS-400-18-LT (5.3103) |
| Piston | Stainless 1.4104 (DN25 and above) | Stainless 1.4104 (AISI 420) | Stainless 1.4104 (DN25 and above) |
| Stem | Steel 1.0718 | Stainless AISI 420 | Stainless 1.4305 (AISI 303) |
| Sealing rings | Metal-reinforced graphite (lower T1, upper T4) | PTFE + carbon fibre | Metal-reinforced graphite (T1) |
| Lantern (intermediate piece) | Grey iron 5.1301 (DN25 and above) | Grey cast iron | Grey iron 5.1301 (DN25 and above) |
| Handwheel | Grey iron 5.1301 | Grey cast iron | Grey iron 5.1301 |
| Stud / nut | Steel 5.6 / 5.2 | Carbon steel | Steel 5.6 / 5.2 |
| Disc spring | 50CrV4 | Depending on model | 50CrV4 |
Which body? Below 300 °C on water and steam lines not exceeding 16 bar, grey iron PN16 is the economical choice; ductile iron is preferred on outdoor lines exposed to shock or frost. On steam lines above 16 bar and at temperatures approaching 350 °C, ductile iron PN40 should be selected. You can match the flange gasket to the temperature on the gaskets page.
Advantages
Removable Installation
- Flanged ends let the valve be removed from the line easily.
- No welding or threading work is needed.
Standard Length
- EN 558 Series 1 face-to-face.
- Fits directly in place of existing globe valves.
Ring Replacement
- Graphite rings are renewed while the body stays in the line.
- Maintenance downtime is short.
Two Pressure Classes
- PN16 and PN40 on the same flange standard.
- Selection follows the line pressure.
Known Kv
- Flow coefficient is defined for every size.
- Pressure drop is calculated in advance.
Construction and Design Features
- Globe body with two flanges drilled to EN 1092-2
- Lower and upper sealing rings compressed by the bonnet studs
- Stainless piston sliding between the rings
- 50CrV4 disc springs that keep the ring preload
- Rising-stem handwheel operation
Send the size, pressure class, medium and operating temperature through the Request a Quote form; we will reserve the valve with the right flange class and body material from stock.
How to Choose?
- Match the flange classCheck whether the mating flange is drilled to PN16 or PN40.
- Compare temperature with the bodyAbove 300 °C choose ductile iron PN40 instead of grey iron.
- Verify the size with KvCalculate the pressure drop from the line flow using the Kv value.
- Measure the installation lengthMake sure the EN 558 Series 1 length fits the gap in the line.
- Plan gaskets and boltsOrder a temperature-rated flange gasket and bolt set together.
Complementary Products
Why ORFA?
Other Piston Valves
Our Flanged Piston Valves
ORFA supplies flanged piston 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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