SU1583791A1 - Pneumometric densimeter of liquid - Google Patents

Abstract

This invention relates to the field of automatic control of the composition of liquid media, in particular, to pneumometric fluid density meters. The purpose of the invention is to reduce the determination error due to the instability of the liquid level in a closed vessel. The end section of the negative pneumometric tube at the point of rupture is directed upwards in the vessel and placed in an additional, open-bottom movable pneumometric tube coaxially and hermetically fastened on a cylindrical float partially immersed in the reference liquid, combining their internal cavities, and in the upper and lower parts an additional pneumometric tube is made of three-needle constrictions centering the additional pneumometric tube with respect to the end portion of the minus pneumometric tube Two radially and oppositely directed horizontal nozzles are connected at the same level and at some distance from its end to the bottom of the additional pneumometric tube, and a cylindrical screen with a conical lower part, rigidly connected to the vessel, is located above the nozzles under the float. removal of air bubbles from the float. 1 il.

Description

This invention relates to a measurement technique.

The aim of the invention is to reduce the uncertainty of the determination due to the non-instability of the liquid level in a closed vessel for the reference liquid.

The drawing shows the proposed densitometer.

The densitometer consists of plus and minus pneumometric tubes 1 and 2, a differential pressure gauge 3, an air preparation device 4, a closed vessel 5 for the reference fluid,

a pressurized float 6, an additional pneumometric tube 7, an end section 8 of the negative pneumatic tube at the point of its rupture, two three-needle stops 9, two nozzles 10 and a screen 11.

Densitometer works as follows.

In the air preparation unit 4, the air is cleaned and its pressure is stabilized. Air tubes 1 and 2 form air pressures proportional to the density of the monitored fluid. For

ate

00 00

h

WITH

 Subtracting the unchanging part of the pressure drop formed in measuring pneumometric tubes 1 and 2 is a closed vessel 5, which is included in the gap of the minus pneumatic tube 2, with a float 6, an additional pneumometric tube 7, the end section 8 of the minus air tube at the point of its rupture, two three-needle stops 9, two nozzles 10 and a screen 11.

The subtracted differential depends on the immersion into the reference fluid, nozzles 10 through which air from the additional pneumometric tube 7 is bubbled.

The additional pneumometric tube 7 is rigidly and hermetically fixed on the float 6 and is connected to its internal cavity. When the float and the pneumatic tube are filled with air, the degree of immersion of the floats and, consequently, the nozzles 10 is constant regardless of the level of the liquid.

The distance from the lower end of the pneumometric tube 7, on which the nozzles 10 are attached, is determined by the force of the surface tension of the liquid, since this is the only reason for the need for additional air pressure in the tube 7 to form and subsequently break the air bubbles from the outlet of the nozzle 10 With an internal nozzle diameter of 4 mm for water, this additional pressure does not exceed 10 mm water. The distance from the place of attachment of the nozzles to the tube 7 to its lower end must be more than 10 mm,

Air bubbling occurs only through the nozzles 10 (not through the open lower end of the tube 7).

The size of the nozzles 10 and the dimensions of the screen 11 exclude air bubbles in the area of the float.

Bubbles on the walls of the float would change its effective volume and, as a result, the depth of the nozzles 10 and the value of the formed differential.

Density Conversion Function

AP g (-Ld - LodQ),

where AP is the differential pressure measured by differential meter 3, Pa;

g — free fall acceleration, m / s;

L - sensor base, m; L is the base of the compensator (depth of the nozzles 10 in the reference liquid), m; dsd - density of controlled and reference liquids, kg / m3,

The source of additional errors of the compensator is the variation (instability) of the base of the compensator LO. The technical solutions in the proposed device allow

reduce variation cA to 0.1 mm and

in less.

Claims (1)

Invention Formula A pneumometric fluid density meter containing a sensor with positive and negative pneumometric tubes, a closed vessel for the reference fluid, connected to the rupture of the negative pneumometric tube, an additional pneumometric tube located in the vessel for the reference fluid, a differential pressure gauge and an air conditioning device, characterized in that to reduce the determination error, it additionally introduced a float, three-needle stops, two nozzles and a cylindrical screen with a tapered lower part, and the float is made open at the bottom, movable, in the form of a tube and placed in a vessel for the reference liquid, three-needle stops are installed in the upper and lower parts of the float, the nozzles are directed in opposite directions and mounted horizontally, the cylindrical screen is located above the nozzles, and the end portion of the negative pneumometric tube installed with access to the internal cavity of the float 8 9 n ffi five 70