Butterfly Valve Seals
A butterfly valve seal is used in butterfly or discs valves ensuring the reliable function. This seal is radially compressed or decompressed during valve operation, thereby stopping or opening fluid flow. They are used wherever a shut-off valves is sufficient for flow regulation.The decisive factor for the corect function of the seal is smooth and low friction contact surfaces and as little possible compression of seal by disc.
DESCRIPTION
Butterfly valve seals are installed in butterfly valves and enable process control in plants and systems. The elastomer ring is radially compressed during the closing process and thus closes the flow of all types of media. The decisive factor for the correct function of the seal is the low friction and low compression of the butterfly valve seal material. Correct function at high temperatures and in different media is also decisive, especially in CIP/SIP cleaning media.
The butterfly valve seal material must always be selected according to the operating conditions. A wide range of materials allows us to make the right choice of materials for the most diverse applications
A good choice leads to very good sealing behavior, resistance within a wide temperature range, outstanding operational performance, high reliability and optimized service life
| EPDM | HNBR | VMQ | FPM | |
|---|---|---|---|---|
| Lower temperature limit | -40 °C | -40 °C | -20 °C | -20 °C |
| Upper temperature limit | 140 °C | 110 °C | 140 °C | 160 °C |
| Upper temperature, short time | 160 °C | 120 °C | 150 °C | 180 °C |
| Aqueous media | 3 | 3 | 1 | 1 |
| Steam | 3 | 0 | 1 | 1 |
| CIP/SIP | 3 | 2 | 1 | 1 |
| Dairy products | 0 | 1 | 3 | 3 |
| Aliphatic hydro-carbon | – | 1 | 2 | 3 |
| Aromatic hydro-carbon | – | – | 2 | 3 |
| 3 – Very good | 2 – Recommendable | 1 – Applicable | 0 – Limited use | ─ Unsuitable |
Butterfly valves in process control plants and systems in the beverage industry, dairy and the chemicals and pharmaceuticals industries.
| Material base | EPDM | HNBR | VMQ | FPM |
| Material code | E5540 E5542 |
H3320 | S8030 | F9970 |
Beverage industry:
- Use of EPDM material as proven solution
- Thermal resistance in steam and sterilization up to +140 °C, shortly to +160 °C
- Suitable for cleaning processes and aqueous media.
- In applications where are used nitric or formic acid, EPDM is the best solution compared to other materials.
Dairy industry:
- EPDM, FPM, VMQ or HNBR material are used depending on fat content and temperature,
- FPM, VMQ and HNBR are resistant to grease at high temperatures and concentrations but, in certain cleaning media
have a shorter lifetime than EPDM.
Pharmaceutical and chemical industry:
- EPDM, FPM, VMQ or HNBR materials are used, depending on the media and solvents used.
- FPM is resistant to certain oils and some aromatic oils, but shows limited resistance to alkaline cleaning agents
and swells in acids, then it is necessary to select cleaning media compatible for FKM.
For applications that may require alternative materials or for verification current availability of tools and part numbers, contact us.
Dimensions correspond to DIN and ISO standard pipe dimensions:
Standard metric: DN 15 to DN 250
Standard inch: 1″ to 6″
Other dimensions, standard form, version with lip and high version available on request.
Surface quality:
| Roughness | Ra | Rmax |
| Sealing surfaces on the valve | 0.05 .. 0,3μm | ≤ 2,5 μm |
| Sealing area of the shaft | 0.05 .. 0,3μm | ≤ 2,5 μm |
Notes:
| Dimensions: | Should strive for minimum necessary and maximum permissible actuating forces |
| Tolerances | Lowest possible tolerances with regard to the seal and the installation space |
| Surfaces on the dynamic area | Perfectly smooth without gaps or seams |
Installation
When streching the seal over the valve, avoid sharp edges, ledges and threaded surfaces on the shaft.