SU939999A1 - Vibration density meter probe - Google Patents

Description

(54) VIBRATION PLOT NUMBER PROBE

one

The invention relates to a measurement technique and can be used to measure the density of gas, in a breech chamber, to measure the density of the front gas on main gas pipelines And underground gas storages.

Vibration densitometers are known which contain, as a vibrator, in a controlled environment, a sensitive element to the tallic membrane or the ij blade.

However, the sensitivity, and consequently, the accuracy of the above mentioned pp numbers, is limited by the large inertia of the metal membrane or is the blade.

The closest technical solution to the proposed. is a vibrating densitometer probe containing an inner and outer tubular elements about a vibration-sensitive element, installed in the inner tubular element and in contact with a controlled medium, excitation system

sensitive element and the pickup of vibrations of a vibration sensitive element, including pieesi. crystal. The vibration-sensitive element is made in the form of a metal blade with a protrusion (2j. The presence of a protrusion increases the inertia of the blade, thereby reducing the sensitivity and, consequently, the measurement accuracy.

The purpose of the invention is an accurate measurement of the density of the gas.

Claims (2)

This goal is ensured by the fact that in the probe of a vibration densitometer containing an external and internal tubular elements, a vibration-sensitive element installed in the internal tubular element and in contact with the controlled medium, the excitation system of the vibration-sensitive element and the vibration pick-up system of a VIBrationio sensitive element. including a piezocrystal, a vibration-sensitive element is made in the form of a dielectric plastics, on which electrets are fixed on both sides, with di An electric plate is installed in the inner annular protrusions of the inner tubular element and is fixed between two metal half-cylinders introduced into the excitation system. FIG. 1 shows a probe, side view, in perspective view; in fig. 2 - lower part of the probe, cross section. The probe assembly of the vibration densitometer includes a plate 1, at the top and bottom to which electrets 2 of the same polarity are attached. The upper 3 and lower 4 dielectric semi-cylinders of the inner tubular element are located outside the upper 5 and lower 6 metal semi-cylinders of the excitation system, and the plate 1 is fixed on both sides by the semi-cylinders 5 and 6 of the excitation system and the four semicircular protrusions 7-10 of the inner tubular element. To secure the wires to the semicylinders, nests 11 and 12 are measured. The exciter wires are connected to the semicylinders 5 and 6 and along the grooves 13. and 14 the wires from the D5 piezocrystal are led through the central groove 16. The probe assembly is pressed into the outer tubular element 17. Wires in the grooves of the piezocrystal are poured with epoxy resin before pressing. The outer tubular element is connected to the upper part of the probe 18 by means of a lug 19 (Fig. 2). The device works in the following way. When the probe is immersed in the test medium, the latter surrounds (or flows around) plate 1. The electrets 2 pasted on plate 1 face the same face outwards. When applying a variable signal to the semi-cylinders 5 and 6 of the excitation systole, the alternating electric field between the semi-cylinders 5 and 6 interacts with the constant electric fields of the two electrets 2, forcing them to oscillate together with the plate 2. At the same time, the attached mass of the gas , surrounding plate. To collect information about the oscillation frequency of the plate to one of the fixed ends of the plate, fasten it with a piezocrystal 15, the signal from which is transmitted to the circuit of the device through wires laid in the central groove 1G. Plate frequency is a measure of the density of the monitored medium. The proposed device provides an increase in the accuracy of measurements due to the use of a dielectric in the general quality of a sensitive element, since the dielectric has a lower density compared to metals and a sufficiently high mechanical strength (for example, a pin of optical fibers of equal length stuck together in one plane with and Poisson’s ratio not less than 0.2). This reduces the inertia of the vibrating plate and increases resistance to chemical corrosion. In addition, the use of the proposed device makes it possible to manufacture a plate with a given oscillation frequency by using electrets as a protrusion and simplifying the probe design by using metal semi-cylinders as an electrostatic excitation system. Claims of the Invention Vibration densitometer probe comprising an external and internal tubular elements of a vibration-sensitive element installed in an internal tubular element and a contacting medium, the excitation system of the vibration-sensitive element and a vibration pickup system of the vibration-sensitive element, including a piezocrystal, distinguished by To measure the accuracy of gas density, the vibration-sensitive element is filled in the form of a dielectric plate, on which there are anchorages fixed to # 1, the dielectric plate being installed in the inner annular protrusions of the inner tubular element and secured between two metal half-cylinders introduced into the excitation system. Sources of information taken into account the legal expertise 1.Patent of France No. 2317644, cl. Q01 N9 / 00, 1977. 2. US patent number 4037461, class. 73-82, 1977 (prototype).