An Introduction to Mini-Valves
Drallim’s manually operated miniature valves are designed for use with instrument air, gases, vapours, aqueous liquids and light hydrocarbons in metal or plastics tubing systems of up to ¼” in or 6mm OD. Typical uses include compressed air systems, pneumatic control and instrumentation, process stream sampling and analysis.
Materials & Media
The valves are available in brass and if required they can be supplied plated to order. Most valves can also be supplied in 316 stainless steel as a special order. Springs, when called for, are invariably stainless. ‘O’ rings are normally in Nitrile Elastomer, but Butyl or Viton are also readily available on request. Stems, when not brass or stainless steel, are in Delrin Acetal.
These have smaller hexagons than the usual nut for the tube size in question and therefore give a particularly compact and elegant installation. Normal sealing is by the unique Drallim reusable captive seal. This consists of rectangular-sectioned ring of elastomeric material, nitrile rubber for example, located in an undercut within the union nut. Tightening this compresses the ring against the tube wall, providing both seal and tube grip. The nut need never be removed from the valve: one simply pushes the tubing through to the abutment in the body, turns the nut to finger-tightness, then adds 1-1/2 revolutions by spanner. To release, the nut is slackened and the tubing pulled out, leaving the seal within the nut. Neither tubing nor seal is permanently deformed and the joint can be remade again and again. For pressures exceeding 10 bar (150psi) and/or temperatures over 90 degrees centigrade the valves can be supplied with conventional metal nuts and olives.
Valves in the 1510, 4510 and 2510 range embody an ISO taper male stud for direct connection to a parallel tapping in manifolds and equipment.
With soft plastics tubing it is often convenient to use Push-on barbed spigot connections. Any Drallim valve Can be thus equipped using the adaptors on page 3 Opposite. The small brass turnings are plain o.d. sized at one end and are simply pushed into the union nut and tightened as if a tube.
In case of any uncertainty as to the suitability of a Drallim Mini Valves in any respect please call and discuss with one of our technical sales engineers.Fittings Mini valves