Pressure regulator type 139 – BV for low and medium gas pressure
Pressure regulator type 139-BV is pilot operated gas pressure regulator for low and medium pressure, which ensure a constant down stream pressure (p). The regulator is controlled by a diaphragm and spring. They can be provided with shut-off device for low and high pressure or for high pressure. They can be used with natural gas, LPG, air, nitrogen, etc.
In its initial position (no gas in the installations), the regulator is closed (i.e. shutter forced by the spring is pressed against the seat). The pad unit of the shut-off mechanism is spaced from the seat allowing the flow of gas to the lower part of the shutter. The pilot is in the open position. When the installations are filled with gas, gas (at an inlet pressure value) flows through the valve casing and shutter openings and reaches the pilot via the impulse line V and the pre-pilot. The relationship between the actuators (diaphragm, spring, pad unit…) is established in the pilot according to the set outlet pressure. This leads to the formation of a control pressure, which enters the chamber under the regulator diaphragm via an impulse line, pushing the diaphragm up and separating the shutter from the nozzle. This pressure also reaches (through an orifice) a chamber located above the diaphragm, establishing a balance. The top chamber is discharged to the outlet line via the impulse line. In this way, the shutter moves to such position in relation to the nozzle so as to ensure the set outlet pressure. The aim of the orifice is to provide the required inertness for proper operation of the regulator. If the inlet pressure has a tendency to increase, it reaches the pilot and the top chamber of the diaphragm housing via the impulse line (downstream of the regulator). Acting on the pilot diaphragm, it closes the pilot. In this way the control pressure upstream of the pilot increases and acting on the bottom side of the regulator diaphragm, it counteracts the outlet pressure acting on the top side. The pressures under and above the diaphragm are almost equalised, causing the spring to push the entire diaphragm assembly, rod and shutter, thereby reducing the outlet pressure to the set value. If the outlet pressure has a tendency to decrease, the opposite happens. Pressure regulator type: 139-BV, when failed, moves to the closed position. If the diaphragm breaks, the pressures under and above the diaphragm are almost equalised, causing the spring to push the diaphragm assembly and the shutter, thus closing the regulator.
Gas pressure regulators type 139-BV are equiped with a pilot type: 117. Pilot type: 117 is used for low and medium pressure control. In the absence of pressure, pilot is in open position, i.e. force of the spring, through stirrup act on the rod and maintain the nozzle opened. Letting the gas (inlet gas in regulator p ) in installation, gas flow through the pilot and through impuls pipe act on upper side of regulator 1 diaphragm. Outlet pressure from regulator p2, through impuls pipe, act on diaphragm, which together with spring maintain the control pressure p constant. Control pressure is through impuls pipe bringed up at the upper side of regulator diaphragm. At the setted value of control pressure, pilot is still opened, and gas flow from upper dipahragm hosuing of regulator to lower dipahragm housing of regulator. Further increase od pressure p2 close the pilot and pressure in uper and lower dipahragm housing is equalised. Regulator spring close the regulator. Set point of control pressure p is established by the adjusting screw and the spring. In order to increase control pressure, rotate clockwise the adjusting screw, and to decrease the control pressure rotate counterclockwise the adjusting screw.
Gas pressure regulators type 139 and type 139- BV are equiped with a pilot type 116-PP when inlet pressure is higher than 1 bars. Pilot type 116-PP is used for low and medium pressure control. In the absence of pressure, pilot is in open position, i.e. force of the spring, through rod act on the shutter and maintain the nozzle opened. Gas from regulator inlet (at pressure p ) is supplied to pilot type 1 116-PP inlet and flows over perforated sieve and filter cartridge to reach the nozzle. Outlet pressure from regulator p, through impuls pipe, act on diaphragm, and together with spring opposes 2 inlet pressure thus insures the value of pressure p ‘ to stay constant. Pressure p ‘ is through impuls pipe bringed up at the pilot regulator type 117 inlet. Hot water (90/ 70 °C) flow channels are drilled in the body of pilot regulator type 116- PP to prevent it from frezzing during pressure reduction process. Heating of pilot regulator is optional, not mandatory.