Sealing Washers, Usit Rings, Copper Rings
Sealing Technology
Sealing washers, Usit rings and copper rings seal threaded ports on the flat face beneath the hex, that is on fittings, plugs, drain screws and gauge connections. The category holds 163 items from Fluidics equipment, Riegler, Stauff and Wika. Available are PTFE sealing rings for G 1/4 to G 1, captive PVC sealing rings, PTFE flat sealing rings to EN 837 for pressure gauges, and copper rings for G 3/8 to G 1 as well as metric sizes from 20.2 x 25.9 x 1.5 mm to 22.2 x 28.9 x 1.5 mm, mostly in packs of 100.
For a water-glycol loop PTFE and PVC are the uncritical choice. Copper rings seal reliably but belong only in a single-metal assembly; in pipework mixing stainless steel and plastics they should be avoided. Usit rings consist of a metal washer with a bonded elastomer, and the same rule applies as for O-rings: EPDM is correct in cooling water, while NBR and FKM are materials for oil, compressed air and chemicals.
Sealing rings in a water-glycol loop - version, size and suitability
| Version | Size | Material | Water-glycol loop |
|---|---|---|---|
| Threaded sealing ring | G 1/2, G 3/4, G 1 | PTFE | suitable |
| Flat sealing ring to EN 837 | G 1/4 | PTFE | suitable, for gauge ports |
| Captive sealing ring | G 3/4 | PVC | suitable |
| Threaded sealing ring | G 3/8, G 1/2, G 3/4, G 1 | copper | single-metal assembly only |
| Metric copper ring | 20.2 x 25.9 x 1.5 mm | copper | single-metal assembly only |
| Metric copper ring | 21.2 x 26.9 x 2 mm | copper | single-metal assembly only |
| Metric copper ring | 22.2 x 28.9 x 1.5 mm | copper | single-metal assembly only |
| Usit ring | by thread | steel or stainless steel with elastomer | suitable with EPDM, not with NBR or FKM |
- Plugs and drain screws on headers, filters and pump housings
- Gauge and sensor ports with a flat seating face to EN 837
- Fittings on coolant distribution units and make-up water stations
- Replacing aged copper rings with PTFE where stainless steel and plastics are mixed
- Recurring maintenance with stock held in packs of 100
- Test and measuring points whose connections are opened and closed regularly
