RU46849U1 - TENSOR RESISTANCE POWER SENSOR - Google Patents

Abstract

The utility model relates to load-measuring equipment and can be used in the oil industry, as well as in other industries to obtain information about static changing compressive or tensile forces in force and weight measuring systems. The strain gauge force sensor is characterized by high accuracy of force measurement and reliability in operation. The maximum reduced error in measuring the force is 0.5%. This is achieved by the fact that in the sensor containing two parallel-mounted elastic elements interconnected by a jumper having each strain gage half bridge and force-sensing surfaces, a wide through-groove of a rectangular shape is made on each elastic element of symmetrically force-sensing surfaces, on the parallel sides of the inner surface of which are glued as mirror image of each other half-bridge strain gages and filled with a compound that is resistant to temperatures in the range from - 60 ° C to + 60 ° C, and elastic elements with power-sensing surfaces are made with the possibility of limited rotation relative to each other in parallel planes.

1 s.p. f-l, 5 ill.

For publication in the newsletter on the title page of the utility model description

recommended figure 1

Description

The utility model relates to load-measuring equipment and can be used to measure the force applied to the polished rod of a rocking machine during oil production.

A strain gauge force sensor is known, comprising two parallel-mounted elastic elements rigidly connected by a jumper, force-sensing surfaces are located on the elastic elements, respectively, three on the side of the loading force and on the side of the supporting surface, on the outside of each elastic element there is a strain gauge half-bridge closed by a lid with seal - rubber ring [1].

The disadvantages of the known force sensor include the lack of self-installation of the sensor between the cross-arms of the rocking machine when the load is perceived by force-sensing surfaces. Due to the irregularities of the surfaces of the upper and lower traverses that are in contact with the sensor (or the traverse is skewed) when loading the sensor with the force applied to the polished rod of the rocking machine, the sensor can contact the traverses (both from the upper and the lower) at one or two points, which reduces the sensitivity of the sensor to perceived load.

The location of the strain gauge half-bridge on the outer surface of the elastic element of the sensor reduces the accuracy of measuring the force applied to the polished rod of the rocking machine. The relative reduced error in measuring the force of such a sensor varies from 1.5% to 4%. The reliability of the sensor is also reduced. When the sensor is operated at temperatures up to -60 ° С, which is typical for the regions of Western Siberia and the Far North, there is a weakening of the tightening of the screws that secure the cover of the strain gauge half-bridge, which leads to its premature exit

from work when exposed to climatic factors - rain, snow, dust, dirt.

The closest technical solution to the proposed one is a strain gauge force sensor containing two parallel-mounted elastic elements rigidly connected to each other by a jumper, on the outside of each elastic element there are strain gauges closed with a lid with seals. The caps are fastened to the elastic element of the force sensor in pairs using spacer sleeves and rubber o-rings [2].

This sensor has the same disadvantages as the sensor [1]. The only advantage of the sensor [2] compared to the sensor [1] is its higher reliability of fastening the covers of the strain gage half bridge, due to the fact that the screws of the covers are replaced by distance bushings, tightening the covers in pairs on each elastic element, which however does not exclude the possibility of snow and moisture in the strain gage half bridge due to the relaxation of rubber sealing elements during prolonged use at low temperatures (up to -60 ° C), which ultimately reduces the reliability chica.

The utility model is based on the task of creating such a design of a strain gauge force sensor that would differ from the analogue and prototype in higher accuracy of measurement of the force acting on the elastic elements and higher reliability in operation.

The problem is solved in that in the strain gauge force sensor on each elastic element of the symmetrically force-sensing surfaces there is a wide through-hole of a rectangular shape, on the parallel sides of the inner surface of which half-bridge strain gages are glued to each other and filled with a compound that is resistant to temperatures ranging from - 60 ° С to + 60 ° С, and elastic elements with force-sensing surfaces

made with the possibility of limited rotation relative to each other in parallel planes.

Figure 1 shows a strain gauge force sensor, side view; figure 2 is the same, a top view ;; figure 3 is a section aa in figure 2; figure 4 is a view of B in figure 3 with the cover removed; figure 3 shows the strain gauge force sensor in the node of the cable suspension of the rocking machine.

The strain gauge force sensor contains elastic elements 1 and 2 connected by a jumper 3, on the elastic elements there are respectively force-sensing surfaces 4, 5, 6, 7 and 8, 9, 10, 11. Surfaces 4, 5, 6, 7 - from the side of the loading force , and the same surfaces 8, 9, 10, 11 - from the side of the supporting surface (surfaces 10, 11 on the elastic element 2 are conventionally not shown). On each elastic element 1 and 2 of symmetrically force-sensing surfaces there is a wide through-through groove 12 of a rectangular shape, on the parallel sides of the inner surface of which strain gauges 13, 14 of the strain gauge half-bridge are glued to each other. The strain gauges of the other half-bridge on the elastic element 2 (not shown conditionally) are glued in the same way as the strain gauges 13 and 14. The strain gauges of both half-bridges are filled with a Vixint-type compound.

The protrusions of a square shape 15 and 16 of the jumper 3 are included in the grooves of the same shape of the elastic elements 1 and 2 with a small gap of 0.5 ... 0.6 mm (FIGS. 3 and 4), which allows limited rotation of the elastic elements 1 and 2 relative to each other in parallel planes. The elastic elements 1 and 2 and the jumper 3 are pressed against each other (pulled together) by means of the covers 17 with fixing screws 18, screwed into the ends of the square protrusions of the jumper. This design of the force sensor provides the possibility of self-installation of the force sensor between the cross-arms of the rocking machine when the load is perceived by force-sensing surfaces. The force sensor is in contact with its power-sensing surfaces with the upper and lower traverses of the rope suspension of the rocking machine despite their bias

or irregularities of the contact surfaces at least at three points on each side (from the side of the power-receiving and supporting surfaces) of FIG. 5. As a result, the total contact area is significantly increased, which increases the sensitivity of the sensor to the current force and the stability of its perception. The location of the half-bridge strain gauges on the parallel sides of the inner surface of a wide through-groove of a rectangular shape is mirrored relative to each other, as shown by experiments on loading the sensor on a load-bearing installation in the mechanical testing laboratory of the Institute for Superplasticity of Materials of the Academy of Sciences of Russia (IPSM AN RF), increases the accuracy of measuring the current force . The maximum reduced error in measuring the force is 0.5%.

Filling the strain gages of both half-bridges with a Vixint-type compound increases the reliability of the force sensor by ensuring guaranteed tightness of the strain gage half-bridge in the operating temperature range from -60 ° C to + 60 ° C.

The strain gauge force sensor 19 (figure 5) during operation is installed in the node of the cable suspension between traverses 20 and 21 with a fixed (special device) polished rod 22. When the machine is rocking in the cables 23 and 24 there is a force P / 2 , and in the polished rod 22 - force P (measured), compressing the elastic elements 1 and 2 through the traverses 20 and 21, mainly in the working zone of deformation, where the strain gauges are located.

A weak current arises in the strain gauges, which is amplified and converted by the microcontroller 25, built into jumper 3, into a digital signal transmitted via cable 26 (RS-485 interface) to the control room server (or, if necessary, to a laptop computer) as a real value the measured force on the polished rod of the rocking machine, which allows you to automatically calculate the actual daily production rate of an oil well.

The sensor is made in the conditions of mechanical assembly production, it does not require scarce materials, unique components and purchased products, it has successfully passed trial operation at NGDU OAO ANK, Bashneft.

The utility model can be used in the oil industry, as well as in other industries to obtain information on static changing compressive or tensile forces in force and weight measuring systems.

Sources of information:

1. Force sensor. 9A5. 159.008. Advertising brochure GUPNN Avitron-Oil, a subsidiary of the Ufa Instrument-Making Production Association.

2. RF patent No. 2164669, cl. G 01 L1 / 22, 1999. Strain gage force sensor.

Claims (2)

1. A strain gauge force transducer comprising two parallel-mounted elastic elements interconnected by a jumper, each having a tensor resistor half-bridge and force-sensing surfaces, characterized in that on each elastic element symmetrically the force-sensing surfaces there is a wide through groove of a rectangular shape, on parallel sides of the inner surface of which glued like a mirror image of each other, half-bridge strain gages and filled with a compound resistant to the effects of temperatures in in the range from - 60 ° С to + 60 ° С. 2. The strain gauge force sensor according to claim 1, characterized in that the elastic elements with force-sensing surfaces are made with the possibility of limited rotation relative to each other in parallel planes.