SU667864A1 - Vibration-type density meter - Google Patents

Description

(54) VIBRATION DENSITY

one

The invention relates to a measurement technique and can be used to continuously measure the density of liquid media. ,

According to the main author. St. No. 450990 is known for a densitometer containing a sensitive element made coaxially with a gap located in a cylindrical body of a straight elastic tube connected by thick ends to the inner surface of a cylindrical body,

excitation and removal of transverse oscillations of the elastic tube U.

The disadvantage of this densitometer is that the effect of the effective inertia mass of the liquid medium on the elastic tube is weak, which does not allow one to accurately determine the density of the Discount medium.

The aim of the invention is to improve the accuracy of measuring the density of liquid media.

The goal is achieved by the fact that in the proposed densitometer in thickened cages of the D-elastic tubing there are made longitudinal through channels communicated with a gap formed by an elastic tube and a body, the size of which is less than three external radii of the elastic tube.

At the same time, the effective inertial mass of the elastic tube increases in accordance with the Stokes formula for the inertial mass

.2. .-2J21V

where MO is the mass of the elastic tube; .. p is the density of the liquid medium;

Gd is the inner radius of the elastic tube;

g is the outer radius of the elastic tube;

R is the inner radius of the cylindrical body.

The diagram shows a sensing element 1, made in the form of a straight elastic tube with channels 2 for the passage of a liquid medium, a cylindrical body 3 with an assembly 4 for fastening the excitation system 5 and picking up oscillations of the elastic tube, the base 6 of the pipeline, the amplifier 7 and a recording device 8.

The device works as follows. --- With the help of the amplifier 7 and the oscillation excitation system 5, the natural transverse oscillations of the elastic tube 1 are excited. Changes in the density of the liquid medium cause changes in the natural vibration frequency of the elastic tube, which is detected by the recording device 8.

The passage of a liquid medium in the annular gap between the elastic tube and the cylindrical body allows to increase the effective inertial mass and, with a change in the density of the liquid medium, obtain a significant change in the natural oscillation frequency of the elastic tube.

Preliminary tests have shown that with respect to the size of the gap to the outer radius of the cylindrical tube.

equal to 0.1, effective knertsionna mass of water in the gap increases. 10 times Vibration density meter according to the author. St. No. 450990, characterized in that, in order to improve the measurement accuracy, in the thickened ends of the elastic tube. Longitudinal through channels communicated with the gap formed by the elastic tube and the body, the size of which is less than the three outer radii of the elastic tube, are made.

Sources of information taken into account in the examination

1. USSR author's certificate No. 450990, cl. G 01 N 9/00, 1972.