Upstream pressure balanced relief regulator

Code: R1490PB

The type R1490PB is a high capacity back pressure or relief regulator of packless gland design and capable of close, stable control of upstream pressure. These regulators can be used with air, gases, oil, water or any fluid which is compatible with the materials of construction.

A pressure regulating valve maintains the loading pressure in the upper diaphragm case and this is balanced by the controlled pressure which acts under the diaphragm. Loading pressure may be air or gas and must come from a separate supply. The loading pressure regulator normally has internal relief but in those cases where an alternative non relieving regulator is used an independent bleed from the upper diaphragm cases must be arranged. The loading pressure is approximately equal to the controlled pressure.

A double seated body is normally used for the type R1490PB but a balanced single seat construction is available for applications which require smaller flows or where tight shutoff is essential. Double seated plugs are hand lapped to obtain the best possible shut-off and for all sizes except 1″ composition 0-ring seating is available as an alternative.

A tapped connection in the lower diaphragm casing allows the use of an external sensing line. This enables the pressure sensing point to be some distance upstream of the regulator or taken from an associated vessel or pressure stage.


1″, 1½”, 2″, 2½”, 3″, 4″ & 6″ (25,36,50,65,75,100 & 150mm)

Flanged as required to 300lb (NP 40) maximum.

1″ 1½” sizes can be supplied with screwed connections.

Iron, Carbon Steel, St/Steel, Aluminium Bronze.

316 grade stainless steel. Aluminium bronze body has Monel trim as standard. Optional 0-ring seats are Viton or PTFE.

Nitrile or Viton. St/Steel can be supplied – consult Factory.

0.07 – 13.8 BarG

Limited by diaphragm and seating materials.

Nitrile – 20ºC to +100ºC – Viton 30ºC to + 200ºC – PTFE to + 200ºC
With St/steel diaphragm and double seated body with metal seats temperatures to 300ºC are possible.