SU647535A1 - Rate-of-flow meter - Google Patents

Description

one

The invention relates to a measurement technique and can be used, in particular, to measure the flow rate of a liquid.

Flowmeters are known that measure the flow rate of a flowing medium through the deformation of a sensitive element, such as a diaphragm. In this case, the deformation of the sensing element is sensed by the strain gauge 1.

These flowmeters have a relatively low sensitivity.

Closest to the invention to the technical essence is a flow meter, comprising a housing with two plates arranged radially opposite each other, and which are mounted to strain gauges connected in a bridge circuit. The change in resistance of the strain gauges leads to the imbalance of the bridge and serves as a measure of flow 2.

However, the use of strain gauges made, for example, from thin wire or formed by spraying a semiconductor film film, leads to a decrease in sensitivity, reliability and deterioration of metrological characteristics.

In order to increase the sensitivity and accuracy of the measurement, in the proposed p) approach () as far as the sensitive element is designed as a semiconductor diaphragm consisting of a central part separated from the peripheral C-shaped slit, strain gages are located on the bridge between the ends;

FIG. I shows a section of the described flow meter along the axis of symmetry; in fig. 2 type of flow meter on top; in fig. 3 - the cross section of the sensing element.

The flow meter contains an I- case (for example, a part of the pipeline) with flanges 2. The cross-section of the case 1 is blocked by a sensitive element — a disk 3. The disk 3 consists of two parts: the central 4 and the circumferential part 6 separated from it by the circular C-shaped slot 5, clamped using rings 7 and screws 8 in case 1.

The sensing element - the disk 3 is made in the form of a single-crystal semiconductor diaphragm, and in its body in the area of greatest deformation, the strain gages 9 made by the lvnn & s technology have been placed on the bridge between the ends of the C-shaped gap ..:. :: -. f v «- For the first yr-good}: the flowmeter performance c .. the sides of the disk 3 under the tensor resistance) 9 are made rectangular rfbidopka Yu (| 5ir), which reduces the thickness of the disk .З.,. ) "Works as follows / 4V g; When the flow of the measured medium flows through the body, a pressure drop occurs in front of the sensing element - disk 3 and behind it, causing deformation of the central part 4 of the sensing element 3. This deformation is sensed by the strain gages 9, the output signal from which it can be significant, which makes it possible to use it without intermediate amplifiers according to the scheme of measuring bridge - indicator device. Formula 11: jubilee A flowmeter comprising a housing inside which a sensing element is located with strain gauges connected in a bridge circuit, characterized in that, in order to increase sensitivity and measurement accuracy, the sensing element is designed as a semiconductor diaphragm consisting of a central part separated from the peripheral C-shaped gap, on the bridge between the ends of which are placed the strain gauges. Sources of information taken into account in the examination; 1.Levin V.M. Low-expense flowmeters for industrial automation schemes. M, 1972, p. 55. 2. The patent of France No. 2194953, cl. G 01 F 1/00. 1974.

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