SU734536A1 - Weight density meter - Google Patents

Description

The invention relates to the field of measuring the density of liquid media.

A weight densitometer is known that contains a sensing element in the form of a pipe segment connected to the sensor bed and to one of the arms of the measuring arm, a compensation circuit with an I-retulator in feedback and balancing the counterweight moved by the engine along the second arm (£ 1).

The most close by the technical sush- ¹ NOSTA to the invention is a weight densitometer comprising a sensitive element in the form of a pipe segment connected to the main pipe using flexible rubber cuff strain gage 'mounted on the sensor and is included in the measuring circuit.

This densitometer o has a low measurement accuracy of £ 2]. ₂

The aim of the present invention is to improve the accuracy of measurements.

The goal is achieved by the fact that the weight densitometer is additionally equipped at the edge2

At least three load cells, while the load cells are installed in pairs above and below the sensing element and are interconnected by elastic ties, as well as by the fact that the load cells are included in adjacent arms of the measuring bridge circuit.

In FIG. 1 shows a weight densitometer, oition view. in Fig. 2 is an electrical circuit for activating strain gauges.

The densitometer consists of a sensitive element 1 connected to the main pipeline, 2 with the help of flexible rubber cuffs 3 and provided with gaskets 4 made of fluoroplastic, elastic elements'. 5 and 6 with load cells 7 and 8, rigidly connected by fasteners 9,

The load cells 7 located above the sensitive element in the bridge circuit are connected in series and mounted relative to the load cells 8 in the adjacent arm of the measuring bridge circuit.

With such an installation of strain gauges, the following equation is valid: ' ^{P kc = ΣΕ} · κο> (1) the weight of the sensitive element together with the liquid medium in it; deformation of the strain gauge located above the sensitive element;

£ _Kc - deformation of the strain gauge located under the sensitive element.

In the absence of a liquid medium in the sensitive element, expression (1) is converted to the form:

Weight is numerical or where; P _to - the weight of the sensing element; and - deformations, respectively, of strain gauges located above and below the sensing element in the absence of liquid in it; medium.

liquid medium Ρς, maybe you *** P »P-P

C cs ^r _s - ^ kfM - ^ (Che-ChU (3)

The expression in brackets can be replaced by deformation increments:

^E ^ ks- ^E Yu (4)

Where ϊ d В is the strain increment of the strain gauge mounted above the sensitive element in the presence of a liquid medium Е- _{П <} r (5) where: d ε is the strain increment of the strain gauge installed under the sensitive element in the presence of liquid medium.

Since it is always £ _kc , the quantity δ £ is negative.

Substituting (4) and (5) in (3) ^ the floor— ρ _ο = ςα ^ ς | αΜ ₍₆ )

By measuring the strain increment of strain gauges, it is possible to determine the weight of the liquid medium in the sensitive element of the density meter using expression (6).

The density of the liquid medium is determined from the expression: η-P / x / yde <y _ the volume of the internal cavity of the sensing element.

734536 4

To measure deformations in the densitometer, semiconductor strain gages are used, the output signal of which is a change in resistance. The strain gauges are wired into the measuring bridge shown in FIG. 2.

The load cells 7, mounted above the sensitive element in the bridge circuit are connected in series. The load cells 8, mounted under the sensitive element, are also included in series and are installed in the adjacent shoulder of the bridge.

The resistance of the resistors 12 and 13 in the other shoulders of the measuring bridge is equal to РР = R

43 'aphid K is a constant coefficient, R is the load cell resistance, N is the Number of load cells. The resistor 14 serves to balance the measuring bridge.

A stabilized supply voltage ’is applied to terminals 10 and 11, and the voltmeter 15 is calibrated in density values.

Density meter works as follows.

When a controlled fluid is supplied to line 2, the weight is a sensor. of each element 1 increases, which causes stretching of the prestressed elastic elements 5, and, accordingly, a change in the resistance of the load cells 7. At the same time, the elastic elements 6 are compressed, which causes a change in the resistance of the load cells 8. A change in the resistance of the load cells 7 and 8 leads to an imbalance of the measuring bridge circuit, to terminals 10 and 11 of which stabilized voltage is applied. The imbalance of the measuring bridge is proportional to the density of the controlled fluid. The density value is determined by the scale of the voltmeter 15, the graduated low density slurry.

in one

Claims (2)

With the installation of gravity strain gauges, a right &amp; moreover, the equator is equalized eG R. ..; r., (1) ime; P, is a sensitive sensory &amp; ment coincides with the Hitsky medium located in it; Е - deformation of the strain gauge located above the sensitive element; - deformation of the strain gauge, located under the sensitive EP &amp; In the absence of a liquid medium in the sensing element, expression (1) transforms to the form: sch; p is the weight of the sensitive element; and deformation, respectively, of strain gauges located above the sensitive element and below it in the absence of a LIQUID medium in it. The weight of the liquid medium P mutation can be calculated as Р Р -Р С КС to Рс () - ((3) The expression in brackets can be replaced by the Deformation increments: Е ЕКС-ЕК; (4) tne i d Е - the deformation increment of the strain gauge installed above the sensitive element in the presence of a liquid medium in it. TOE: d E is the infringement of the strain gauge deformation, installed under the Sensitive EEF element when there is a liquid medium in it. Since always Ey. . s, the value of l E is negative. Substituting (4) and (5) in (G) semi- (6) Measuring the deformation increments of ten forces, you can determine by the expression (6) the weight of the liquid medium contained in the sensitive section density density of the liquid medium is determined from the expression: p oud. V is the volume of the internal cavity of the sensing element. To measure the deformations in the densitometer, semiconductor teresistors are used, the output of which is the change in resistance. Strain gauges using wires included in the measuring bridge, shown in FIG. 2. Strain gages 7, fixed above the sensitive element, are connected in series in the bridge circuit. The strain gauges 8, mounted under the sensing element, are also connected in series and installed in the adjacent shoulder of the bridge. Resistors 12 and 13 in the other arms of the measuring bridge pa &amp; .г., Пз, е К - constant coefficient, R - resistance of the strain gauge, N - number of strain gauges. Resistor 14 serves to balance the measuring bridge. Terminals 10 and 11 are supplied with a stabilized supply voltage, and voltmeter 15 is graduated in terms of density. Densitometer works as follows. When a controlled liquid is supplied to the pipeline 2, the weight of the sensing element 1 increases, which causes stretching of the previously nodulated & elastic elastic elements 5, and, accordingly, the resistance of the strain sensors 7 also changes. At the same time, the elastic elements 6 are compressed, which causes the resistance of the strain sensors 8 to change. A change in the resistance of the strain gauges 7 and 8 leads to an imbalance of the measuring bridge circuit, at terminals 10 and 11 of which a customized voltage is applied. The unbalance of the measuring bridge is proportional to the density of the controlled liquid medium. The density value is determined on a scale of a voltmeter 15, calibrated in units of slurry density. An inventive Bessed densitometer containing a sensing element in a tube section of a pipe connected to a pipeline with flexible rubber cuffs with a strain gauge mounted on it, included in the design scheme, characterized in that it has an additional accurate measuring circuit and is additionally sized according to one measure three strain gauges, while the strain gauges are installed in pairs over the sensitive element and under it and are interconnected by elastic SV513Yami. 2 Weight densitometer, tp and h y and with the fact that the load cells on the adjacent shoulders of the measuring bridge circuit, Information sources taken into account tfi expertise 1, Author's certificate of the USSR 5O1338, cl. From 01 N 9/02, 1976. 2, USSR Copyright Certificate No. 86054, class, C 01 9/02, 1949.