SU78184A1 - Instrument for determining the pressure of fluid in the stream - Google Patents

Description

The instruments used to determine the total static and dynamic head of the fluid flow, made in the form of a Pitot tube, have the disadvantage that they do not allow separate determination of the static and the minimum head of liquid in the stream.

In the proposed device, these shortcomings are eliminated by the fact that in the pipe network of the Pitot tube an air line is used, allowing the difference between the readings of the liquid levels in the U-shaped tubes depending on: the value of the pressure in the air line to separate the static and dynamic pressure of the liquid in the flow.

The drawing shows a diagram of a device for determining the pressure of a liquid.

The pipeline of the Pitot tube 1 and the U-shaped tubes 2 and 3 are connected to the pipeline //.

To the outer channel of the Pitot tube and to the U-shaped tubes 3 and 4 is connected to the pipe 12.

Pa pipelines 11 and 12 supplied throttle washers 9 (or jets), which make it possible to reduce air pressure from Ytr to hg at

51 Code Release 1, part I, 1950

This last is chosen so that the condition is met;

Ltr i

i.e., h g should be such that at the channels of the Pitot tube, when it is in the flow, there is always air movement, regardless of the magnitude of H of the fluid flow.

The difference between the I and the need to choose within the h- -NR: 10-15 mm of water. Art.

Air to pipes 11 and 12 comes only when valves 7, 8 and 10 are open, the pressure of which must be the same and is determined by the difference in water levels in the U-shaped 2, 3 and 4. The water level in the O-shaped tubes is equal. It must be the same and is controlled by valves 8 or 10.

With the same value of Atr in the pipeline // and 12, the difference in water levels in the U-shaped tube 3 will be equal to 0.

In tube 2, the difference in the levels of the liquid will show the total head of the flow H and / g, n, defined by the formula I (I + Ltr) -h-TpM.H of water. Art.

In the tube 3 connected to the pipelines // and 12, the difference of the levels will show the magnitude of the dynamic129

and the total pressure in tube 4 (H „h- / i}. Since / g is known, the static pressure value will be equal to:

ffcT (+ Lgr) - / Zrp mm WATER. ST.

Subject invention

A device for determining the pressure of a fluid in a stream, made in the form of a Pitot tube, characterized in that, for the purpose of separate

determining the static and dynamic pressure of the fluid, it is equipped with an air duct connected by means of throttle washers to the Pitot tube network, and three U-shaped tubes, based on the difference in the readings of the fluid levels in which and depending on the static, dynamic and total pressure of the fluid in the stream.

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