Number Of Flange Holes For Different Sanitary Valves
The number of flange holes depends on the connection standard, nominal size, and flange design. A sanitary valve with Tri-Clamp or welded ends has no conventional flange bolt holes, while a flanged valve uses a defined hole count, hole diameter, and bolt-circle diameter. These dimensions must match the mating pipeline flange.
Why Flange Hole Count Varies
A sanitary valve may use several connection types, so DN size alone cannot determine its flange pattern.
- Tri-Clamp: No bolt holes; a clamp secures the ferrules.
- Butt-Weld: No bolt holes; the valve is welded to the tube.
- Threaded: No flange holes; threaded ends connect to fittings.
- Flanged: Uses bolt holes arranged on a pitch circle.
Connection Standard Matters
DIN, ISO, ASME, and other standards can use different flange dimensions. Two valves with the same DN size may still have different bolt-hole spacing or diameters.
Sanitary Ball Valve Flange Patterns
A sanitary ball valve can use clamp, weld, thread, or flange connections. For a flanged model, the following dimensions should be confirmed:
- Flange outside diameter
- Number of bolt holes
- Bolt-hole diameter
- Bolt-circle diameter
- Face-to-face dimension
Some sanitary ball valve designs are available in sizes such as DN10–DN150, with connection options depending on the model.
Why Clamp Valves Have No Flange Holes
A sanitary tri clamp ball valve uses ferrules and a clamp instead of multiple flange bolts. This design supports quick assembly and removal during cleaning or maintenance.
The same distinction applies to butterfly valves. A tri clover butterfly valve may use clamp, weld, thread, or flange ends, so the connection type must be checked before replacement.
How to Check the Correct Hole Pattern
Before purchasing a replacement valve, the following checks should be completed:
1. Identify the flange standard
Confirm whether the pipeline uses DIN, ISO, ASME, SMS, or another standard.
2. Confirm nominal size
DN size gives the basic scale but does not define the complete flange pattern.
3. Measure bolt-circle diameter
The pitch-circle diameter must match the mating flange.
4. Check hole count and diameter
Both must match the existing flange and fasteners.
5. Compare the drawing
The dimensional drawing should be the final installation reference.
Typical Specifications
| Item | Typical Value |
|---|---|
| Body material | SS304 / SS316L |
| Common size | DN25–DN250 |
| Working pressure | Up to 10 bar |
| Temperature | About -20°C to 120°C |
| Surface finish | Ra ≤0.8 μm |
| Connection | Clamp / Weld / Thread / Flange |
| Seal | EPDM / Silicone / NBR |
Practical Selection Rule
Flange-hole count should never be selected from DN size alone. The existing standard, hole count, hole diameter, bolt-circle diameter, gasket, and face dimensions should all be checked before a sanitary valve is ordered.
This approach reduces installation errors caused by selecting the correct nominal size but the wrong connection pattern.
