SU957022A1 - Liquid/air differential manometer - Google Patents

Description

(54) LIQUID-AIR DIFMANOMETER SELF-RANGE The invention relates to the measurement of pressure, and more specifically to liquid differential pressure gauges, and can be used, for example, when equipping boiler plants. Liquid pressure gauges and barometers are known for measuring pressure drop 1. The disadvantage of these devices is a change in the reference level of the gauge fluid relative to the zero scale. The closest to the invention to the technical essence and the achieved result is a liquid-air differential pressure gauge containing negative and positive measuring tubes with inlet valves, connected in the upper part by a jumper filled with air, to the skal and equalizing chamber 2. A disadvantage of the known device is the availability of movable parts associated with the implementation of the balancing chamber. The aim of the invention is to simplify the design by eliminating moving parts, as well as providing the possibility of refilling the pressure gauge. The goal is achieved by the fact that the differential pressure gauge is equipped with fluid and air chambers, which are located above and below the equalization chamber respectively and connected to it by means of nozzles, the air chamber connected in the upper part to the jumper and to the equalizing chamber, and the ends of the nozzles are inserted inside the equalizing chamber and are located at the same level with the scale zero. In addition, in the manometer, the lower part of the air chamber and the upper part of the liquid chamber are equipped with taps through which they communicate with the atmosphere. The diagram shows a liquid-air differential pressure gauge, a general sectional view. The device contains a transparent negative measuring tube 1, which is connected in its upper part by a jumper through an air reservoir 2 and a balancing chamber 3 with an opaque plus measuring tube 4. Equalizing chamber 3 has a transparent hatch at the front

a zero risk located at the zero level of the scale of reference 5. The liquid chamber 6 and the air chamber 2 are connected to the equalization chamber by 3 branch pipes, which are inserted into the chamber 3 and terminate respectively with the horizontal ends 7 and 8, which are located at the same level with the zero point of the scale. The measuring tubes are equipped with inlet taps 9 and 10. In the lower part of the air chamber and in the upper part of the liquid chamber, taps 11 and 12 are installed, through which the chambers communicate with the atmosphere. The air in the bridge is air.

Differential pressure gauge works as follows.

In the initial state, the measuring tubes, liquid and, partially, the balancing chamber are filled with liquid, and its level in the negative tube depends on the pressure drop in the system, and in the equalization chamber it is maintained at the zero mark of the reference scale 5. The flow through the diaphragm is determined by the difference in levels liquids in measuring tubes. When the pressure in the system varies, the level of water in equalization chamber 3 deviates slightly due to the compressibility of air. Thus, with increasing pressure, the level in chamber 3 will increase and water through the horizontal edge of end 7 will overflow into air chamber 2, the working volume of air will decrease, and its pressure will increase. When the air pressure is equal to the pressure in the system, the overflow will stop, and the water level in balance chamber 3 will be set to zero.

As the pressure in the system decreases, the water level in chamber 3 decreases, and air through the horizontal edge 8 of the nozzle will flow into the water chamber 6, the air pressure will decrease as its working volume remains unchanged. When the air pressure is equal to the pressure in the system, the flow of air will stop, and the water level in chamber 3 will be set to zero risk. Thus, an increase in air pressure in the working volume occurs due to the filling of the air chamber 2 with water, and a decrease due to the removal of air from the working volume into chamber 6. At the same time, the volume of the air chamber should be P times the volume of the liquid chamber, where P is working overpressure in the system.

When measuring with a pressure gauge under operating conditions, when the static pressure in the system increases and decreases many times, all the air from the air chamber 2 through chamber 3 and the ends 7 and 8 will flow into chamber 6, the water level in chamber 3 will not coincide with zero risk, and The differential pressure gauge must be refilled.

To refill the differential pressure gauge with atmospheric air, it is necessary to close taps 9 and 10 and open taps 11 and 12, while

water from chambers 2 and 6 will flow out and they will be filled with air; close taps II and 12 and open taps 9 and 10, while the water partially fills the chamber 2, and the air pressure will be equal to the pressure in the system; open tap 11 briefly to

the water forced the air out of chamber 6, while the differential pressure meter was ready to measure the pressure drop.

Comparative simplicity allows for the use and reliability of the proposed device.

Claims (2)

1. An air-liquid differential pressure gauge containing negative and positive measuring tubes with inlet taps, connected in the upper part by a jumper filled with air, a scale and a balancing chamber, characterized in that simplifying the design by eliminating moving parts, it is equipped with a fluid and air chambers, which are located above and below the balancing chamber respectively and connected to it by means of nozzles, with the air chamber connected in the upper part to the jumper and to the balancing chamber, and cameras and are located on the same level with the zero mark of the scale. 2. A differential pressure gauge according to claim 1, characterized in that, in order to enable its refilling, the lower part of the air chamber and the upper part of the liquid chamber are equipped with taps through which they communicate with the atmosphere. Information sources, taken into account during the examination 1. Preobrazhensky V. P. Thermotechnical measurements and devices. M., “Energie, 1978, p. 407-408. ° 2. USSR author's certificate No. 157815, cl. G 01 L 13/14, 05.11.62 (prototype).