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Low gas pressure regulator type 127-BV

Low gas pressure regulator type 127-BV for high and low pressure

Pressure regulator type: 127-BV is direct action device for low pressure, which ensure a constant downstream pressure (p2). 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.


Pressure regulator type 127 initially (when there is no gas in the pipeline) is in the open position, i.e. the force of the spring through the diaphragm pulls the steam with the ca to the open position. When gas is introduced into the installation, pressure acts on the lower surface of the diaphragm and overpowers the spring force, closing the regulator until the outlet line pressure p and the set-point outlet pressure are equalised. As the pressure rises above the set-point, the force below the diaphragm increases, overpowering the spring force and closing the regulator. The increase in pressure by the closing time is expressed as a percentage by the closing unit (SG). Pressure drop in the outlet line (i.e. further gas consumption) leads to the regulator re-opening and performing its primary function – maintenance of a constant outlet pressure within the tolerance limits, represented as a percentage – by the regulator unit (AC). The force of the spring is determined by the spring tensioner. This type of the regulator integrates a balance diaphragm, which ensures better regulation and considerably higher flow.

An increase in pressure to the limit pressure value for stopping the operation (the pressure at which the shut-off device is activated) leads to the upward movement of the shut-off mechanism diaphragm assembly, which pulls the lever and activates the lock cog, releasing the bush and, at the same time, the pin/spindle, which, subject to the force of the load spring of the shut-off, pushes the head to the seat. When the shut-off valve is activated as a result of overpressure, the diaphragm assembly overpowers the force of the VP spring, which is determined by the VP spring tensioner. The shut-off mechanism is activated (as a result of outlet under-pressure) by the force of the NP spring pushing the diaphragm assembly downwards, which then activates the lock cog through the lever and releases the bush, i.e. unlocks the shut-off mechanism. The force of the NP spring is determined by the NP spring tensioner.

Unlocking of shut-off device:

Remove the manual puller from the lower casing of the shut-off. Turn the manual puller and screw it onto the pin/spindle. Slowly pull the manual puller just to allow the gas to flow through the shut-off head and keep it in the same position for a few seconds until the pressures equalise, then pull the manual puller all the way through and release it. A properly functioning shut-off mechanism will stay in the locked position. Unscrew the manual puller from the pin/spindle and re-screw it into the lower casing of the shut-off.

The impulse line takes the outlet pressure gas p to the shut-off mechanism pilot, which is an actuator of the 2 shut-off mechanism. The pressure increase from p do p increases the force acting on the diaphragm (a) of the 2 blv shut-off mechanism pilot and releases the high pressure spring (b), which results in axial movement of the pilot lock stem (c), which turns the key of the shut-off mechanism (e) by a puller (d). By turning the key, the space for the lock ball is provided (f) and the stem (g) forced by the spring pushes the lock head (h) against the seat stops
the gas flow. A pressure drop from p to p decreases the force that acts on the pilot diaphragm of the shut-off mechanism, causing the low pressure spring (i) to move the pilot lock stem, which activates the shut-off mechanism as in the previous case.

Technical manual:

Safe use guide: