Back Pressure Regulators

A back pressure regulator holds the pressure upstream of itself at a set point. Below the setting it stays closed; as the line reaches the setting it opens just far enough to pass the excess on downstream or to vent, so the upstream pressure holds steady while the flow changes. That is the reverse of a pressure reducing regulator, which controls the pressure after it. Back pressure regulators keep a pipeline, sampling system or reactor at a steady working pressure and protect upstream equipment from over-pressure. The range here is four units in brass and 316L stainless steel, with settings from 0 to 100 mbar up to 50 bar and line sizes from 1/4 to 1 inch, three of them for liquids as well as gases.

Start with the pressure to be held. For millibar settings, 0 to 100 or 0 to 1000 mbar, the PHF CS3 BP12 is the unit: gas only, with a 7 bar inlet limit. The other three take up to 60 bar at the inlet in their threaded versions, in ranges reaching 1.5, 3, 8, 15, 30 or 50 bar, so the set point decides the version. Then the duty. The PHF BS2 BP12 is brass, 1/4 and 1/2 inch, for gases and liquids from -20 to +80 C. The PHF CS2 BP12 is 316L stainless throughout, 1/4 to 1/2 inch or flanged, for corrosive gases and liquids, to +200 C with FPM seals or down to -40 C with EPDM. The PHF CS2 BP10 is the same build in 3/4 and 1 inch with a Kv of 8.5 m3/h, for larger flows. For hazardous areas the three stainless units carry ATEX as well as PED; the brass unit carries PED. All four come in a version degreased for oxygen service.