SU1379652A2 - Barometer - Google Patents

Abstract

The invention relates to a measurement technique and makes it possible to increase the measurement accuracy by reducing the temperature error. In the device, the sensitive elements 2Au 3 form an airtight cavity A, at the level of which a hollow sealed vessel 5 is placed. Connecting the vessel 5 by capillary 6 to the gas cavity B formed in the tube 1 above the manometric liquid 4 contributes into the cavity x A and B. The volume of cavity B of vessel 5 is made considerably larger than the volume of cavity B,. A change in the atmospheric pressure leads to the occurrence of an error signal at the output of the null indicator 8. Using the compensator 9, the initial position of the sensitive elements 2 and 3 is restored. 1 Il. g (L

Description

The invention relates to a measurement technique, namely to instruments for measuring atmospheric pressure, and is an improvement of the invention according to the author. No. 1262312.

The purpose of the invention is to improve the measurement accuracy by reducing the temperature error.

The drawing shows the construction of a barometer.

Sensitive elements 2 and 3 are installed in the tube 1 in the lower part of the tube, forming an airtight cavity A, and the effective area of the sensitive element 2 is larger than that of the sensing element 3. The tube 1 is filled with gauge fluid 4 to form in the upper part of the cavity B ,. At the level of cavity A, a hollow hermetic vessel 5 with cavity B, which communicates with cavity B, capillary 6, is installed. In this case cavity B is much larger than cavity B ,. The centers of the elastic sensing elements are interconnected by a rod 7 and are connected with a null indicator 8 and a power compensator 9. The cavities A, B ,, Bj are filled with gas.

The barometer works as follows.

The initial value of the atmospheric pressure is compensated by the pressure of the liquid column taking into account the ratio of the effective areas of the sensitive elements 2 and 3. The change in the atmospheric pressure causes the sensitive elements to deviate from the initial position. In this case, a mismatch signal occurs at the output zero of the indicator 8, according to which equilibrium is restored with the help of a power compensator 9. The magnitude of the change in atmospheric pressure is determined by the known compensation compensation value

&R.

 And s,

where f | - force developed by the compensator;

S) —effective area of the sensing element 3. Then the value of the atmospheric pressure is determined.

PO PD P „,

where d is the initial value of atmospheric pressure.

In order to eliminate the dependence of the compensation force on the temperature of cavity A and the cavities B and B connected by the capillary are filled with gas, so that the condition

Ra. ,

15 20 25

thirty

with 49 d

0

where RD is the pressure in the cavity A;

Pg is the cavity pressure, B, and B, S is the effective area of the sensing element 2. Equality is observed without error if the temperature of the cavities filled with gas is the same, which is ensured by placing these cavities in the same temperature conditions, for which the level of the intermembrane cavity is set a sealed hollow vessel 5 connected by a capillary with cavity В ,, which contributes to the equalization of temperatures in cavities A and B and thereby reduces the temperature error. The volume of the cavity In the sealed vessel 5 must be significantly greater than the volume of the cavity, above the liquid.

Claims (1)

Invention Formula Barometer auth. No. 1262312, characterized in that, in order to improve the measurement accuracy by reducing the temperature error, it is equipped with a capillary tube and a hollow sealed vessel installed at the level of the intermembrane cavity, the sealed vessel being connected by a capillary tube to a cavity above the liquid filled with gas, the volume which is less than the volume of a sealed vessel.