The Precision Controls Division (PCD) of Marsh Bellofram Corp. has announced the Type 77 industrial vacuum pressure regulator series. The Type 77 is a single control unit for high-performance monitoring and control of pressures from 29-in Hg vacuum to 150 psi.
Featuring an aluminum die-cast construction with weather-resistant vinyl paint finish, the vacuum regulator incorporates a fixed negative 15 psig bias spring to maintain vacuum outputs and controlled system pressure from 29-in Hg, with flow capacity to 40 SCFM. An adjustable opposing range spring increases controlled pressure outputs. Output pressure droop under varying downstream flow conditions is minimized by the incorporation of an aspirator tube, which adjusts the air supply valve opening in accordance with flow velocity. The dampening action of the aspirator tube maintains continuous and stable output pressure. Units are available with 1/4 NPT, 3/8 NPT, 1/4 BSPT, or 3/8 BSPT port size. A balanced supply valve, using a reinforced rolling diaphragm, keeps regulator output unaffected by changes in supply pressure.
The regulator may be installed either upstream or downstream from the vacuum pump. Upstream installation is preferred for applications in which the rapid evacuation of a vessel or system is required, because pump exhaust capacity is normally greater than that of the regulator. In all other applications, the regulator can be located between the pump and the vessel. Units may be either pipe-, panel-, or bracket-mounted to suit particular application needs.
Marsh Bellofram Corp., www.marshbellofram.com