Attached resistance strain sensor assembly and mounting process thereof

Abstract

The invention discloses an attached resistance strain sensor assembly includes a sensor body, wherein substrates are respectively mounted at two ends of a lower end face of the sensor body, a heat insulation layer is provided between two of the substrates, the heat insulation layer covers the lower end face of the sensor body, an outer cover is covered above the sensor body, two ends of the outer cover are respectively mounted on the two substrates, and a wiring terminal is provided at one side of the outer cover. The sensor assembly can be mounted to a structural member by electric welding, so that the influence of high temperature on the performance of an elastic part in the sensor body during welding is reduced, the output value of the sensor is still in an expected range, and a more accurate load measurement value can be obtained.

Claims

1. An attached resistance strain sensor assembly, comprising a sensor body, wherein substrates are respectively mounted at two ends of a lower end face of the sensor body, a heat insulation layer is provided between two of the substrates, the heat insulation layer covers the lower end face of the sensor body, an outer cover is covered above the sensor body, two ends of the outer cover are respectively mounted on two of the substrates, and a wiring terminal is provided at one side of the outer cover; wherein welding grooves are formed in two sides of the substrates, and two of the welding grooves are formed in the side wall of one side of the substrates along a length direction of the sensor body.

2. The attached resistance strain sensor assembly according to claim 1, wherein the sensor body comprises an elastomer and a full-bridge type measuring bridge, wherein six elastic bridges are provided on the elastomer, the elastomer is divided into an upper section, a middle section and a lower section along a central axis, a structure of each of the upper section, the middle section and the lower section is a bilaterally symmetrical distribution, and shapes of a left part and a right part of the middle section are I-shaped respectively; the left edge of the upper section is provided with a first elastic bridge connected with a starting position of a first stroke of an I-shaped character at the left part of the middle section, the right part of the upper section is provided with a second elastic bridge which is bilaterally symmetrical to the first elastic bridge, a second stroke of the I-shaped character at the left part of the middle section is provided as a third elastic bridge, the right part of the middle section is provided with a fourth elastic bridge which is bilaterally symmetrical to the third elastic bridge, the left part of the lower section is provided with a fifth elastic bridge which is longitudinally symmetrical to the first elastic bridge, and the right part of the lower section is provided with a sixth elastic bridge which is bilaterally symmetrical to the fifth elastic bridge; strain foils of the full-bridge type measuring bridge are respectively arranged on two sides of the third elastic bridge and the fourth elastic bridge; a connection between the two ends of each elastic bridge and the elastomer must adopt a circular arc transition.

3. The attached resistance strain sensor assembly according to claim 1, wherein one of the welding grooves is semi-waist-shaped.

4. The attached resistance strain sensor assembly according to claim 1, wherein the sensor body comprises an elastomer and a full-bridge type measuring bridge, wherein six elastic bridges are provided on the elastomer, the elastomer is divided into an upper section, a middle section and a lower section along a central axis, a structure of each of the sections is a bilaterally symmetrical distribution, and shapes of a left part and a right part of the middle section are I-shaped respectively; the left part of the upper section is provided with a first elastic bridge connected with an ending position of a first stroke of an I-shaped character at the left part of the middle section along the central axis, the right part of the upper section is provided with a second elastic bridge which is bilaterally symmetrical to the first elastic bridge, a second stroke of the I-shaped character at the left part of the middle section is provided as a third elastic bridge, the right part of the middle section is provided with a fourth elastic bridge which is bilaterally symmetrical to the third elastic bridge, the left part of the lower section is provided with a fifth elastic bridge which is longitudinally symmetrical to the first elastic bridge, the right part of the lower section is provided with a sixth elastic bridge which is bilaterally symmetrical to the fifth elastic bridge; strain foils of the full-bridge type measuring bridge are respectively arranged on two sides of the third elastic bridge and the fourth elastic bridge; a connection between the two ends of each elastic bridge and the elastomer must adopt a circular arc transition.

5. The attached resistance strain sensor assembly according to claim 1, wherein side positioning plates are fixedly connected to side walls of two sides of the substrates via bolts.

6. The attached resistance strain sensor assembly according to claim 1, wherein the outer cover is fixedly connected to the substrates via bolts.

7. A mounting process for the attached resistance strain sensor assembly according to claim 1, wherein by comprising steps of: S1, calculating a deformation value of a structure measuring point and a mounting size of the measuring point; S2, according to a formula δ=C.sub.2×E×ε×ψ×L.sub.0×V, a deformation magnification ratio is $\psi =\frac{.Math..Math.{\mathrm{.Math.}}^{″}.Math.}{{\mathrm{.Math.}}^{\prime }},$ δ is a primary output signal value of a sensor assembly mounted on an equipment when the sensor assembly works, E is a material elastic modulus of a structure to which the sensor is attached, L.sub.0 is a base length of the sensor assembly, V is a measuring bridge voltage, C.sub.2 is a constant (test value), and ε is a strain average value of a structure measuring point when an equipment works, |ε″| is an output total value of a strain absolute value at a patch of a measuring bridge in a middle segment of the sensor when being calibrated on a calibrating device of a base length L.sub.0=100 mm, and ε′ is a strain average value given when the sensor is calibrated on the calibrating device of the base length L.sub.0=100 mm; an appropriate sensor assembly is selected so that a primary output signal value δ.sub.m of the sensor assembly mounted on the equipment can reach 30-60 mV/10V when the equipment works under full load; S3, welding the sensor assembly on the structure measuring point by adopting an electric welding process, wherein a welding point is located at one of the welding grooves; S4, disassembling a side positioning plate; and S5, connecting a secondary meter by the wiring terminal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a structurally schematic view of Example 1.

(2) FIG. 2 is a structurally schematic view of an elastomer of Example 1.

(3) FIG. 3 is a top view of Example 1.

(4) FIG. 4 is a structurally schematic view of the elastomer in Example 2.

DESCRIPTION OF THE EMBODIMENTS

Example 1

(5) As shown in FIGS. 1 and 2, an attached resistance strain sensor assembly comprises a sensor body 1. The sensor body 1 comprises an elastomer 2 and a full-bridge type measuring bridge 3. Six elastic bridges are provided on the elastomer 2, the elastomer 2 is divided into an upper section, a middle section and a lower section along a central axis, the structure of each of the sections is a bilaterally symmetrical distribution, and the shapes of the left part and the right part of the middle section are I-shaped respectively; the left edge of the upper section is provided with a first elastic bridge 2a connected with a starting position of a first stroke of an I-shaped character at the left part of the middle section, the right part of the upper section is provided with a second elastic bridge 2b which is symmetrical to the first elastic bridge 2a, a second stroke of the I-shaped character at the left part of the middle section is provided as a third elastic bridge 2c, the right part of the middle section is provided with a fourth elastic bridge 2d which is symmetrical to the third elastic bridge 2c, the left part of the lower section is provided with a fifth elastic bridge 2e which is longitudinally symmetrical to the first elastic bridge 2a, and the right part of the lower section is provided with a sixth elastic bridge 2f which is symmetrical to the fifth elastic bridge 2e; strain foils of the full-bridge type measuring bridge are respectively arranged on two sides of the third elastic bridge 2c and the fourth elastic bridge 2d; the connection between the two ends of each elastic bridge and the elastomer 2 must adopt a circular are transition.

(6) As shown in FIGS. 1 and 3, the substrates 4 are fixedly installed at two ends of the lower end face of the elastomer 2. Two welding grooves 5 are formed in the side walls of the two sides of the substrate 4 along the length direction of the sensor body 1. The welding groove 5 is semi-waist-shaped. A heat insulation layer 6 is provided between the two substrates 4, and the heat insulation layer 6 covers the lower end face of the sensor body 1. An outer cover 7 is covered above the sensor body 1, two ends of the outer cover 7 are respectively mounted on the two substrates 4, and the outer cover 7 is fixedly connected to the substrates 4 via bolts. One side of the outer cover 7 is provided with a wiring terminal 8.

(7) Each sensor has a corresponding deformation amplification ratio ψ,

(8) $\psi =\frac{.Math..Math.{\mathrm{.Math.}}^{″}.Math.}{{\mathrm{.Math.}}^{\prime }},$
|ε″|, is the total output value of the strain absolute value at the patch of the measuring bridge in the middle segment of the sensor when the sensor is calibrated on a calibration device at the base length of L.sub.0=100 mm, and ε′ is the strain average value given when the sensor is calibrated on the calibration device at the base length of L.sub.0=100 mm. ψ is related to the structural dimensions of the first elastic bridge 2a, the second elastic bridge 2b, the third elastic bridge 2c, the fourth elastic bridge 2d, the fifth elastic bridge 2e and the sixth elastic bridge 2f. Sensor bodies with different ψ can be obtained by different designs. At present, the attached resistance strain sensors with the two different elastomer structures have been serialized by 8 steps according to the deformation magnification ratios thereof, and the values of ψ are 6.0-23.0 respectively.

(9) The assembly mounting process is as follows:

(10) S1, calculating a deformation value of a structure measuring point and a mounting size of the measuring point;

(11) S2, according to a formula δ=C.sub.2×E×ε×ψ×L.sub.0×V, a deformation magnification ratio is

(12) $\psi =\frac{.Math..Math.{\mathrm{.Math.}}^{″}.Math.}{{\mathrm{.Math.}}^{\prime }},$
δ is a primary output signal value of a sensor assembly mounted on the equipment when the sensor assembly works, E is a material elastic modulus of a structure to which the sensor is attached, L.sub.0 is a base length of the sensor assembly, V is a measuring bridge voltage, C.sub.2 is a constant (test value), and ε is a strain average value of a structure measuring point when the equipment works; an appropriate sensor body is selected so that the primary output signal value δ.sub.m of the sensor assembly mounted on the equipment can reach 30-60 mV/10V when the equipment works under full load;

(13) S3, welding the sensor assembly on the structure measuring point by adopting an electric welding process, wherein the welding point is located at the welding groove 5;

(14) S4, disassembling the side positioning plate; and

(15) S5, connecting the secondary instrument by a wiring terminal 8.

(16) The base length L.sub.0 of the sensor assembly is well matched with the deformation amplification ratio ψ thereof, so that the optimal primary high output when the sensor assembly is fully loaded can be obtained. Many years of practical application of the technology in different industrial fields proves that the primary output value δ.sub.m of the sensor used on site ranges from 30 to 60 mV when the sensor is fully loaded. It is 2-3 times of the primary output value of the traditional weighing sensor.

Example 2

(17) Example 2 differs from Example 1 in that the elastomer 2 is different as shown in FIG. 4. Six elastic bridges are provided on the elastomer 2, the elastomer is divided into an upper section, a middle section and a lower section along a central axis, the structure of each of the sections is a bilaterally symmetrical distribution, and the shapes of the left part and the right part of the middle section are I-shaped respectively; the left part of the upper section is provided with a first elastic bridge 2a connected with a ending position of a first stroke of an I-shaped character at the left part of the middle section along the central axis, the right part of the upper section is provided with a second elastic bridge 2b which is bilaterally symmetrical to the first elastic bridge 2a, a second stroke of the I-shaped character at the left part of the middle section is provided as a third elastic bridge 2c, the right part of the middle section is provided with a fourth elastic bridge 2d which is bilaterally symmetrical to the third elastic bridge 2c, the left part of the lower section is provided with a fifth elastic bridge 2e which is longitudinally symmetrical to the first elastic bridge 2a, and the right part of the lower section is provided with a sixth elastic bridge 2f which is bilaterally symmetrical to the fifth elastic bridge 2e; strain foils of the full-bridge type measuring bridge 3 are respectively arranged on two sides of the third elastic bridge 2c and the fourth elastic bridge 2d; the connection between the two ends of each elastic bridge and the elastomer 2 must adopt a circular are transition.

Example 3

(18) An attached resistance strain sensor is used for a 35t bridge crane of Shagang to carry out overload limitation and real-time process metering. With a FWZ-C-35t type instrument, sensors are installed in the middle of the upper surfaces of slot holes of the supporting plate at the two ends of the fixed pulley shaft. ψ=23, L.sub.0=50 mm, Q.sub.m=36.1t, δ.sub.m=2×27.5 mV/10V.

Example 4

(19) An attached resistance strain sensor is used for monitoring the deflection of the section of a girder of a 360-ton bridge crane. With a FWZ-C-360t type instrument, sensors are installed in the middle of the upper surfaces of the fixed pulley beam. ψ=7.5, L.sub.0=150 mm, Δm=13 mm, δ.sub.m=2×31.5 mV/10V.

Example 5

(20) An attached resistance strain sensor is used for a 2×1000t fixed gate hoist of the Altash hydropower station in Xinjiang to carry out overload and underload limitation. With a FWZ-C-1000t type instrument, sensors are installed in the middle of the upper surfaces of the two outer side bracket slots of the fixed pulley. ψ=9, L.sub.0=100 mm, Q.sub.m=1030t, δ.sub.m=46.2 mV/10V, Q.sub.s≤30t.

Example 6

(21) An attached resistance strain sensor is used for a bridge crane of the Xiangjiaba hydropower station to carry out overload limitation and section strength monitoring of a fixed pulley beam. With a FWZ-C-800(200)t type instrument, sensors are installed in the middle of the upper surfaces of the fixed pulley beam. ψ=6, L.sub.0=200 mm, Q.sub.m=824.0t, δ.sub.m=2×30 mV/10V, σ.sub.m=91.7 MP.

Example 7

(22) An attached resistance strain sensor is used for a 100t bridge crane of the kquswagah thermal power station in the Philippine to carry out overload limitation. With a FWZ-C-100t instrument, sensors are installed in the middle of the upper surface of the fixed pulley beam.
ψ=19,L.sub.0=150 mm,Q.sub.m=103.0t,δ.sub.m=43.0mV/10V.

(23) Annotations: ψ—a deformation amplification ratio of the sensor body; L.sub.0—a base length of the sensor assembly; δ.sub.m—a primary output signal value output by the sensor assembly when the equipment works under full load (the voltage of the bridge is 10V); Q.sub.m—a full load value that the equipment bears; Q.sub.s—an underload value of the equipment; Δm—a deflection of the girder when the equipment works under full load; σ.sub.m—a surface stress value of the section surface of the fixed pulley beam when the equipment is fully loaded.

(24) The above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the spirit of the present invention fall within the scope of the present invention. It should be noted that those skilled in the art will appreciate that various modifications and adaptations can be made without departing from the principles of the invention and fall in the scope of the present invention.