SU145036A1 - Pressure meter - Google Patents

Description

Pressure gauges are known that contain a hermetically sealed, heat-insulated chamber with a gas, in one of the walls of which a membrane is mounted, and a differential tracking system, made on measuring transformers.

The proposed pressure gauge is characterized in that to ensure automatic stabilization of the membrane in a neutral position, a ferrite plate is fixed at the inlet of the follower system, rigidly attached to the central part of the membrane and located at a predetermined distance from the core of the measuring transformer It serves to preheat the gas in the chamber to a temperature at which the membrane takes up a neutral position. A resistance thermometer is placed inside the chamber, according to the indications of which the value of the environmental pressure is judged.

A simplified schematic diagram of the pressure gauge described is shown in the drawing.

In a sealed chamber 1, some constant volume of gas is enclosed. A soft membrane 2 is mounted into one of the chamber walls, to the center of which a ferrite plate 3 is rigidly attached. If there is a pressure difference between the chamber cavity and the outer atmosphere, membrane 2 bends to one side or the other from the neutral position and moves the ferrite plate. In order for the pressure inside the chamber to equalize with the external pressure it is necessary to heat the gas to a certain temperature. The moment of equality of pressures is determined by the neutral position of the ferrite plate using a differential tracking system consisting of a measuring transformer 4 and a setting transformer 5, the primary windings of which are connected in series and fed with alternating current 145036-2. The secondary windings through rectifiers 6 and 7 are loaded on resistances 5 and 9, at which the output voltages of the windings are subtracted. The difference of these voltages is fed to the input of the phase-sensitive amplifier W, at the output of which the heating winding 11 is installed, located inside the chamber /.

When the ferrite plate is moved inside the chamber from the neutral position, the gap in transformer 4 increases, the voltage on its secondary winding decreases, and the input voltage W is supplied with a voltage difference of such polarity that the winding // receives power and heats the gas inside the chamber. Having expanded, the gas acts on the membrane, reduces the gap of the transformer 4 and the heating stops.

Thus, the pressure gauge works in such a way that the temperature inside the chamber is automatically maintained at such a level that the pressure inside the chamber is exactly equal to the atmospheric pressure. The pressure of the surrounding medium is judged by the temperature of the gas inside the chamber, at which the membrane is stabilized in a neutral position. The temperature is measured using a resistance thermometer 12 placed inside the chamber.

In order to increase the uniformity of heating of the chamber shell and, mainly, to reduce the power of the heater, the chamber shell is insulated from the surrounding environment.

Subject invention

Claims (2)

1. A pressure gauge containing a hermetically sealed, heat-insulated gas chamber, in one of the walls of which a membrane is mounted, and a differential tracking system, made on instrument transformers, characterized in that, in order to ensure automatic stabilization of the membrane in a neutral position, the trace is inlet ferrite plate, rigidly attached to the central part of the membrane and located at a predetermined distance from the core of the measuring transformer, and at the output of the following The system has a preheating winding that serves to heat the gas in the chamber to a temperature at which the membrane takes up a neutral position. 2. A pressure gauge according to Claim 1, characterized in that a resistance thermometer is placed inside the chamber, according to the indications of which the value of the ambient pressure is judged.