Expansion Tank Membranes
An expansion tank membrane is the rubber bladder in replaceable-membrane tanks that separates water from the gas cushion and keeps the water inside the bladder only.
Replacing a worn or punctured membrane puts booster and heating circuit tanks back into service. The product range consists of 12 sizes for tank volumes from 18–24 L to 1500–2000 L.
Main Applications
- Membrane replacement in booster tanks
- Closed-circuit heating tanks
- Cooling circuit expansion tanks
- Domestic water tanks
- Fire booster pressure tanks
- Spares for periodic maintenance
Technical Data
| Product type | Replaceable expansion tank membrane |
|---|---|
| Sizes | 18–24 L, 35–50 L, 50 L, 80–100 L, 100–150 L, 150–200 L, 200–300 L, 500–750 L, 750–1000 L, 1000 L, 1000–1500 L, 1500–2000 L (product range) |
| Membrane material | EPDM (butyl option) |
| Membrane type | Replaceable, DIN 4807-3 |
| Continuous temperature | −10 °C … +70 °C |
| Fluid | Water, water with up to 50% glycol |
| Compatibility | Confirmed by tank brand and flange size |
| Installation | Replaced by removing the tank flange |
Material Options
| Part | EPDM membrane (standard) | Butyl membrane (option) |
|---|---|---|
| Material | EPDM rubber | Butyl rubber (IIR) |
| Gas permeability | Standard | Low (depending on model) |
| Typical use | Heating and boosters | Tanks needing low gas loss |
| Fluid | Water, glycol water | Water, glycol water |
Which material? The membrane must fit the flange diameter and bladder length as well as the tank volume, so it is confirmed with the tank label data or the size of the existing membrane. Temperature and standard values are taken from the expansion tank manufacturer sheet.
Advantages
Reuses the Tank
- No need to replace the shell
Hygienic
- Water does not touch the shell
Wide Volume Range
- From 18 L to 2000 L
Fast Maintenance
- Replaced by opening the flange
Construction and Design Features
- Bag-shaped rubber body
- Neck seating on the tank flange
- Replaceable design
- Water side inside the membrane
Send the tank volume, brand/flange size and quantity; we will confirm a suitable spare membrane from stock.
How to Choose?
- Determine the tank volumeRead the litres and connection size on the label.
- Check the pressure classChoose a membrane suited to the tank PN.
- Fluid and temperatureState the glycol content and operating temperature.
- Choose the materialRequest EPDM as standard or butyl for low gas loss.
Complementary Products
Why ORFA?
Other Expansion Tanks
Vertical Expansion Tanks
Vertical expansion tanks are floor-standing diaphragm tanks that absorb the thermal expansion of water in closed heating, cooling and booster systems.
Details →
Spherical Expansion Tanks
Spherical expansion tanks are compact diaphragm tanks used in small volume closed heating and domestic water installations.
Details →
Horizontal Expansion Tanks
Horizontal expansion tanks are diaphragm tanks installed horizontally where height is limited, absorbing thermal expansion in closed systems.
Details →Get a quote for your project
Our sales team will prepare the best solution for your needs.