ORIFICE METER WITH PRESSURE VENTING AND EQUALIZING SAFETY DEVICE

摘要

ABSTRACT OF THE DISCLOSUREAn orifice meter including a carrier, which is movable between twoparallel body walls while maintaining sealing engagement therewith. In oneposition it seals around the pipeline flow passage, and in a second positionit seals around an orifice disc service opening in one of the body plates.A small, axially movable valve plug in the body plate adjacent the serviceopening is operative in one position to equalize the pressure in the spacewithin the carrier seals with the rest of the valve body and in a secondposition to vent that space to atmosphere. Interengaging means on the valveplug and a rotatable closure for the service opening prevent removal of theclosure unless the valve plug is in its venting position. The valve plug hastwo annular grooves, each carrying an O-ring to seal against inner surfacesof axially aligned inner equalizing passage and outer vent passage. A transferduct opens from between the two passages to the space within the serviceopening. Bypass ducts opening from the grooves prevent O-ring dislodgement.