A rust resistivity testing device and method with variable compaction degree

Abstract

The present invention provides a rust resistivity test device and method with variable compaction degree, which comprises an electrode device, the electrode device is mounted on a constant load device, the constant load device is placed in a shielding box, the wiring terminal on the shielding box is connected to the power supply of the measuring unit; the shielding box is provided with a side door and a top door, and the measuring unit is mounted outside the shielding box. The device is suitable for measuring the surface resistivity and volume resistivity of rust and other powdery materials under different pressure states, realizes the synchronous application of compressive stress and resistivity measurement, is simple to operate, convenient to maintain, and can improve the accuracy and reliability of the measurement results.

Description

Technical Field

[0001] The invention relates to the technical field of electrical measurement test devices, and in particular to a rust resistivity test device and method with variable compaction degree. Background Art

[0002] Resistivity is an important physical parameter of a material. In the field of electromagnetism, accurate values ​​of volume resistivity and surface resistivity are related to the accuracy of relevant design calculation results. How to effectively and accurately measure the resistivity of materials is the prerequisite for subsequent design calculation work. Taking the study of steel corrosion in concrete structures as an example, the essence of steel corrosion in a natural environment is a galvanic cell reaction. In order to study the corrosion process of steel bars, the resistivity of each material is an indispensable and important parameter in numerical simulation. Among them, the measurement of rust resistivity is a major problem. The rust on the surface of steel bars in concrete is often in a compacted state. For powdered materials, the resistivity will be different due to different compaction states. The resistivity value measured under a pressure-free state is not applicable to other pressure working environments. However, the existing testing equipment can only meet the test of formed solids under a pressure-free state, and cannot meet the resistivity test of powders under pressure and water-containing states. The use of resistivity values ​​under a pressure-free state is bound to result in errors or even mistakes. Therefore, designing an integrated volume resistivity and surface resistivity testing device that can accurately control compressive stress and consider the water content of the sample is of great significance for accurately measuring the resistivity values ​​of rust or other powders in different states. Summary of the invention

[0003] In order to overcome the shortcomings of existing test equipment, the present invention provides a rust resistivity testing device with variable compaction degree, which is suitable for measuring the volume resistivity and surface resistivity of rust and other powders under different pressures and water content, and realizes the resistivity measurement of samples when simulating actual working conditions. The device is easy to operate and maintain, and can improve the authenticity and accuracy of the measurement results.

[0004] In order to realize the above-mentioned technical features, the object of the present invention is realized as follows: a rust resistivity testing device with variable compaction degree, which includes an electrode device, the electrode device is installed on a constant load device, the constant load device is placed in a shielding box, and the wiring terminals on the shielding box are connected to the power supply of the measuring unit; the shielding box is provided with a side door and a top door, and the measuring unit is installed outside the shielding box.

[0005] The electrode device is composed of an upper component and a lower component;

[0006] The upper component is cylindrical, with a circular protective electrode and a cylindrical protected electrode embedded in the lower end, and the protective electrode and the protected electrode are flush with the bottom of the upper component; the outer side of the upper component is provided with a protected electrode terminal and a protective electrode terminal, the protected electrode terminal is connected to the protected electrode through an embedded wire, and the protective electrode terminal is connected to the protective electrode through an embedded wire;

[0007] The lower component is a cylinder with a closed bottom, and its inner diameter is larger than the outer diameter of the upper component; a cylindrical unprotected electrode is embedded in the lower end of the lower component, and the upper end surface of the unprotected electrode is flush with the inner bottom surface of the lower component, and a plurality of drainage channels are arranged on the bottom surface of the lower component; an unprotected electrode terminal is arranged on the outer side of the lower component, and the unprotected electrode terminal is connected to the unprotected electrode through an embedded wire; a displacement meter is installed on the upper part of the outer wall of the lower component, and a liquid collecting tank is arranged on the lower part of the outer wall.

[0008] The constant load device is composed of a bottom plate, a spring, a column, a middle plate, a top plate, a ball joint support, a jacking device and a load sensor; the column is fixed on the bottom plate, and circular holes with an inner diameter larger than the diameter of the column are arranged at the four corners of the middle plate, and the middle plate can slide up and down along the column; the upper half of the column is threaded, and the distance between the top plate and the middle plate is adjusted by nuts at the upper and lower parts of the top plate; the spring under the column can be replaced according to the load holding level;

[0009] The jacking device is supported on the top of the middle plate through a ball joint support, the electrode device is supported on the top of the jacking device, a load sensor is installed on the top of the electrode device, and the load sensor is in contact with the lower end surface of the top plate.

[0010] The lifting device is an electric lifting device, and is lifted and lowered by a controller on the outside of the shielding box; the lifting device is connected to the lifting device terminal on the outside of the shielding box and is provided with electric energy.

[0011] The measuring unit is composed of a power supply, a main line switch K1, a line transfer switch K2, a line transfer switch K3, a voltmeter, an ammeter, an electrode short-circuit switch K4 and a resistor R N The measurement of surface resistivity and volume resistivity is realized by controlling the line conversion switch K2 and the line conversion switch K3; the electrical components of the measuring unit are all located outside the shielding layer of the shielding box.

[0012] The power supply is a DC regulated power supply, which can adjust the voltage;

[0013] The ammeter is a high-precision ammeter equipped with a current amplifier, which can adjust the amplification factor.

[0014] The protective electrode, the protected electrode and the unprotected electrode in the electrode device are made of high-strength conductive materials, and the remaining parts are made of high-strength insulating engineering plastics.

[0015] The terminal, the protected electrode terminal, the protecting electrode terminal and the unprotected electrode terminal all adopt quick-connect connectors.

[0016] The method for conducting resistivity testing using a rust resistivity testing device with a variable compaction degree comprises the following steps:

[0017] Step 1: first, without placing the sample, place the upper component of the electrode device into the lower component, start the lifting device, apply the load to a preset level, and after the load is maintained for a preset time, set the displacement meter reading to zero;

[0018] Step 2: Control the lifting device, remove the load, take out the electrode device, place the sample to be tested in the lower component of the electrode device, make the surface of the sample to be tested flat, and then place the upper component of the electrode device on the sample to be tested, and record the reading S0 of the displacement meter in the no-load state at this time;

[0019] Step 3: Place the electrode device in a constant load device and adjust it to the center; start the lifting device, apply the load to a preset level at a uniform speed, and hold the load for a preset time, and record the displacement meter reading S1 at this time;

[0020] Step 4: When measuring the surface resistivity, set both the line switch K2 and the line switch K3 to the surface resistivity test position R. s , close the main circuit switch K1 and the electrode short-circuit switch K4, adjust the voltage of the power supply so that the ammeter reading is close to the range, and read the current value I1; keep the voltmeter reading unchanged, open the electrode short-circuit switch K4, and read the current value I2;

[0021] When testing volume resistivity, set both line switch K2 and line switch K3 to volume resistivity test position R. v , the subsequent operation is the same as the measurement of surface resistivity;

[0022] Then, the surface resistivity value ρ of the sample to be tested is calculated according to the following formulas (1) to (2): s and volume resistivity value ρ v ;

[0023]

[0024]

[0025] In the formula, ρ s is the surface resistivity of the sample to be tested, ρ v is the volume resistivity of the sample to be tested, resistance R Nis a known resistance value, I1 is the current value when the electrode short-circuit switch K4 is closed, I2 is the current value when the electrode short-circuit switch K4 is open, d1 is the diameter of the protected electrode, g is the distance between the protected electrode and the protection electrode gap, and S1 is the actual thickness of the sample to be tested under pressure;

[0026] Step 5: After the test is completed, unload the load, take out the electrode device, remove the test sample, and clean the electrode device.

[0027] The present invention has the following beneficial effects:

[0028] When using this device, first do not add the sample to be tested. Apply the load to the preset level in the no-load state and hold the load for the preset time. At this time, set the displacement meter reading to zero to eliminate the error caused by the deformation of the electrode device. After unloading, add the sample to be tested, level the sample surface, place the upper component of the electrode device, adjust the centering on the constant load device, apply the load at a uniform speed through the jacking device and hold the load, and record the displacement meter reading when the load is about to end. Turn on the power, control the main switch, conversion line switch, electrode short-circuit switch, adjust the power supply voltage, record the corresponding current value, and then calculate the surface resistivity and volume resistivity of the sample to be tested according to the surface resistivity and volume resistivity calculation formula. During the test, the sample to be tested is always in a loaded state, which can completely simulate the state of the sample to be tested when it is working, and can greatly improve the authenticity and reliability of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0031] Figure 2 It is an axonometric view of the constant load device in the present invention.

[0032] Figure 3 It is a front view of the constant load device of the present invention.

[0033] Figure 4 It is a top view of the electrode device in the present invention.

[0034] Figure 5 yes Figure 4 1-1 cross-sectional view in FIG.

[0035] Figure 6 It is a circuit diagram of resistivity test in the present invention.

[0036] In the figure: power supply 1, constant load frame 2, shielding box 3, terminal 4, line transfer switch K25, line transfer switch K36, voltmeter 7, ammeter 8, main line switch K19, electrode short circuit switch K410, lifting device terminal 11, controller 12, load display 13, displacement display 14, bottom plate 15, spring 16, middle plate 17, column 18, top plate 19, ball joint support 20, lifting device 21, electrode device 22, load sensor 23, displacement meter 24, lower component 25, unprotected electrode 26, protective electrode 27, protected electrode 28, sample to be tested 29, upper component 30, drainage channel 31, protected electrode terminal 32, protective electrode terminal 33, unprotected electrode terminal 34, resistor R N 35. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0038] Embodiment 1:

[0039] See also Figure 1-6 , a rust resistivity testing device with variable compaction degree, comprising an electrode device 22, the electrode device 22 is mounted on a constant load device 2, the constant load device 2 is placed in a shielding box 3, the terminal 4 on the shielding box 3 is connected to the power supply 1 of the measuring unit; the shielding box 3 is provided with a side door and a top door, and the measuring unit is mounted outside the shielding box 3. By adopting the above-mentioned rust resistivity testing device, it is suitable for measuring the surface resistivity and volume resistivity of rust and other powdery materials under different pressure states, and realizes the simultaneous application of compressive stress and resistivity measurement. It is simple to operate and convenient to maintain, and can improve the accuracy and reliability of the measurement results. In the specific measurement process, the electrode device 22 is loaded by the constant load device 2, and during the loading process, the corresponding resistance is measured with the help of the measuring unit.

[0040] Furthermore, the electrode device 22 is composed of an upper component 30 and a lower component 25; the upper component 30 is cylindrical, and a circular protective electrode 27 and a cylindrical protected electrode 28 are embedded at the lower end, and the protective electrode 27 and the protected electrode 28 are flush with the bottom of the upper component 30; the outer side of the upper component 30 is provided with a protected electrode terminal 32 and a protecting electrode terminal 33, the protected electrode terminal 32 is connected to the protected electrode 28 through an embedded wire, and the protecting electrode terminal 33 is connected to the protecting electrode 27 through an embedded wire ; The lower component 25 is a cylinder with a closed bottom, and its inner diameter is larger than the outer diameter of the upper component 30; a cylindrical unprotected electrode 26 is embedded in the lower end of the lower component 25, and the upper end surface of the unprotected electrode 26 is flush with the inner bottom surface of the lower component 25, and a plurality of drainage channels 31 are arranged on the bottom surface of the lower component 25; an unprotected electrode terminal 34 is arranged on the outer side of the lower component 25, and the unprotected electrode terminal 34 is connected to the unprotected electrode 26 through an embedded wire; a displacement meter 24 is installed on the upper part of the outer wall of the lower component 25, and a liquid collecting tank is arranged on the lower part of the outer wall. By adopting the above-mentioned electrode device 22, it can be used to set the sample to be tested 29 inside the corresponding electrode device 22, thereby ensuring that it is loaded and realizing the measurement of its resistance while loading. The residual liquid inside the sample to be tested 29 is discharged through the drainage channel 31. The liquid collecting tank is used to collect the discharged liquid.

[0041] Furthermore, the constant load device 2 is composed of a bottom plate 15, a spring 16, a column 18, a middle plate 17, a top plate 19, a ball joint support 20, a lifting device 21 and a load sensor 23; the column 18 is fixed on the bottom plate 15, and the four corners of the middle plate 17 are provided with circular holes with an inner diameter larger than the diameter of the column 18, and the middle plate 17 can slide up and down along the column 18; the upper half of the column 18 is threaded, and the distance between the top plate 19 and the middle plate 17 is adjusted by the nuts at the upper and lower parts of the top plate 19; the spring under the column 18 can be replaced according to the load holding level. The above-mentioned constant load device 2 can be used to apply pressure to the sample 29 to be tested.

[0042] Furthermore, the jacking device 21 is supported on the top of the middle plate 17 through a ball joint support 20, the electrode device 22 is supported on the top of the jacking device 21, a load sensor 23 is installed on the top of the electrode device 22, and the load sensor 23 is in contact with the lower end surface of the top plate 19. The jacking device 21 can be used to provide a stable load.

[0043] Furthermore, the lifting device 21 is an electric lifting device, and is lifted and lowered by the controller 12 outside the shielding box 3; the lifting device 21 is connected to the lifting device terminal 11 outside the shielding box 3 and provides electric energy. The above electric control method ensures the convenience and controllability of the control.

[0044] Furthermore, the measuring unit is composed of a power supply 1, a main line switch K19, a line transfer switch K25, a line transfer switch K36, a voltmeter 7, an ammeter 8, an electrode short-circuit switch K410 and a resistor R N 35, the surface resistivity and volume resistivity are measured by controlling the line conversion switch K25 and the line conversion switch K36; the electrical components of the measuring unit are all located outside the shielding layer of the shielding box 3.

[0045] Furthermore, the power supply 1 is a DC regulated power supply capable of adjusting the voltage; the power supply 1 can be used to provide a stable current.

[0046] Furthermore, the ammeter 8 is a high-precision ammeter equipped with a current amplifier, which can adjust the amplification factor, thereby ensuring the accuracy of the measurement.

[0047] Furthermore, the protective electrode 27, the protected electrode 28 and the unprotected electrode 26 in the electrode device 22 are made of high-strength conductive materials, and the remaining parts are made of high-strength insulating engineering plastics.

[0048] Furthermore, the terminal 4, the protected electrode terminal 32, the protecting electrode terminal 33 and the unprotected electrode terminal 34 all adopt quick-connect connectors.

[0049] Embodiment 2:

[0050] The method for conducting resistivity testing using a rust resistivity testing device with a variable compaction degree comprises the following steps:

[0051] Step 1: first, without placing a sample, place the upper component 30 of the electrode device 22 in the lower component 25, start the lifting device 21, apply a load to a preset level, and after the load is maintained for a preset time, set the displacement meter 24 reading to zero;

[0052] Step 2: Control the lifting device 21, unload the load, take out the electrode device 22, place the test sample 29 in the lower component 25 of the electrode device, make the surface of the test sample 29 flat, then place the upper component 30 of the electrode device on the test sample 29, and record the reading S0 of the displacement meter 24 in the no-load state;

[0053] Step 3, place the electrode device 22 in the constant load device 2 and adjust it to the center; start the lifting device 21, apply the load to a preset level at a uniform speed, and hold the load for a preset time, and record the displacement meter 24 reading S1 at this time;

[0054] Step 4: When measuring the surface resistivity, set both the line switch K25 and the line switch K36 to the surface resistivity test position R. s, close the main circuit switch K19 and the electrode short-circuit switch K410, adjust the voltage of the power supply 1, make the reading of the ammeter 8 close to the range, and read the current value I1; keep the reading of the voltmeter 7 unchanged, open the electrode short-circuit switch K410, and read the current value I2;

[0055] When testing volume resistivity, set both line switch K25 and line switch K36 to volume resistivity test position R v , the subsequent operation is the same as the measurement of surface resistivity;

[0056] Then, the surface resistivity value ρ of the test sample 29 is calculated as follows: s and volume resistivity value ρ v ;

[0057]

[0058]

[0059] In the formula, ρ s is the surface resistivity of the sample 31 to be tested, ρ v is the volume resistivity of the sample 31 to be tested, and the resistance R N 35 is a known resistance value, I1 is a current value when the electrode short-circuit switch K410 is closed, I2 is a current value when the electrode short-circuit switch K410 is open, d1 is a diameter of the protected electrode 28, g is a distance between the protected electrode 28 and the protection electrode 27, and S1 is an actual thickness of the test sample 31 under pressure;

[0060] Step 5: After the test is completed, unload the load, take out the electrode device 22, remove the test sample 29, and clean the electrode device 22.

Claims

1. A rust resistivity testing device with variable compaction degree, characterized in that: It comprises an electrode device (22), the electrode device (22) being mounted on a constant load device (2), the constant load device (2) being placed in a shielding box (3), the wiring terminal (4) on the shielding box (3) being connected to a power supply (1) of a measuring unit; the shielding box (3) being provided with a side door and a top door, and the measuring unit being mounted outside the shielding box (3); The electrode device (22) is composed of an upper component (30) and a lower component (25); The upper component (30) is cylindrical, with a circular protective electrode (27) and a cylindrical protected electrode (28) embedded at the lower end, the protective electrode (27) and the protected electrode (28) being flush with the bottom of the upper component (30); a protected electrode terminal (32) and a protective electrode terminal (33) are arranged on the outer side of the upper component (30), the protected electrode terminal (32) is connected to the protected electrode (28) via an embedded wire, and the protective electrode terminal (33) is connected to the protective electrode (27) via an embedded wire; The lower component (25) is a cylinder with a closed bottom, and its inner diameter is larger than the outer diameter of the upper component (30); a cylindrical unprotected electrode (26) is embedded in the lower end of the lower component (25), the upper end surface of the unprotected electrode (26) is flush with the inner bottom surface of the lower component (25), and a plurality of drainage channels (31) are arranged on the bottom surface of the lower component (25); an unprotected electrode terminal (34) is arranged on the outer side of the lower component (25), and the unprotected electrode terminal (34) is connected to the unprotected electrode (26) through an embedded wire; a displacement meter (24) is installed on the upper part of the outer wall of the lower component (25), and a liquid collecting tank is arranged on the lower part of the outer wall; The constant load device (2) is composed of a bottom plate (15), a spring (16), a column (18), a middle plate (17), a top plate (19), a ball joint support (20), a lifting device (21) and a load sensor (23); the column (18) is fixed on the bottom plate (15), and the four corners of the middle plate (17) are provided with circular holes with an inner diameter larger than the diameter of the column (18), and the middle plate (17) can slide up and down along the column (18); the upper half of the column (18) is threaded, and the distance between the top plate (19) and the middle plate (17) is adjusted by nuts at the upper and lower parts of the top plate (19); the spring below the column (18) can be replaced according to the load holding level; The jacking device (21) is supported on the top of the middle plate (17) via a ball joint support (20), the electrode device (22) is supported on the top of the jacking device (21), a load sensor (23) is installed on the top of the electrode device (22), and the load sensor (23) is in contact with the lower end surface of the top plate (19).

2. The rust resistivity testing device with variable compaction degree according to claim 1, characterized in that: The lifting device (21) is an electric lifting device, and is lifted and lowered by a controller (12) outside the shielding box (3); the lifting device (21) is connected to a lifting device terminal (11) outside the shielding box (3) and is provided with electric energy.

3. The rust resistivity testing device with variable compaction degree according to claim 2, characterized in that: The measuring unit comprises a power supply (1), a main circuit switch K 1 (9), Line transfer switch K 2 (5) Line transfer switch K 3 (6), voltmeter (7), ammeter (8), electrode short-circuit switch K 4 (10) and resistor R N (35) composition, through the line transfer switch K 2 (5) and line transfer switch K The control of 3 (6) realizes the measurement of surface resistivity and volume resistivity; the electrical components of the measuring unit are all located outside the shielding layer of the shielding box (3).

4. The rust resistivity testing device with variable compaction degree according to claim 3, characterized in that: The power supply (1) is a DC regulated power supply capable of adjusting the voltage; The ammeter (8) is a high-precision ammeter equipped with a current amplifier capable of adjusting the amplification factor.

5. The rust resistivity testing device with variable compaction degree according to claim 3, characterized in that: The protective electrode (27), the protected electrode (28) and the unprotected electrode (26) in the electrode device (22) are made of high-strength conductive material, and the remaining parts are made of high-strength insulating engineering plastics.

6. The rust resistivity testing device with variable compaction degree according to claim 3, characterized in that: The connection terminal (4), the protected electrode connection post (32), the protecting electrode connection post (33) and the unprotected electrode connection post (34) all adopt quick-connect connectors.

7. A method for resistivity testing using the rust resistivity testing device with variable compaction degree as claimed in any one of claims 3 to 6, characterized in that: The following steps are involved: Step 1: first, without placing a sample, place the upper component (30) of the electrode device (22) in the lower component (25), start the lifting device (21), apply a load to a preset level, and after the load is maintained for a preset time, set the reading of the displacement meter (24) to zero; Step 2: Control the lifting device (21), remove the load, take out the electrode device (22), place the test sample (29) in the lower component (25) of the electrode device, make the surface of the test sample (29) flat, then place the upper component (30) of the electrode device on the test sample (29), and record the reading of the displacement meter (24) in the no-load state. S 0; Step 3: Place the electrode device (22) in the constant load device (2) and adjust it to the center; start the lifting device (21), apply the load to a preset level at a uniform speed, and hold the load for a preset time, and record the displacement meter (24) reading at this time. S 1; Step 4: When measuring surface resistivity, turn on the line switch K 2 (5) and line transfer switch K 3 (6) are all set to the surface resistivity test position R s , close the main circuit breaker K 1 (9) and electrode short-circuit switch K 4 (10), adjust the voltage of the power supply (1) so that the reading of the ammeter (8) is close to the range, and read the current value I 1. Maintain the reading of the voltmeter (7) and disconnect the electrode short-circuit switch. K 4 (10), read the current value I 2; When testing volume resistivity, switch the line K 2 (5) and line transfer switch K 3 (6) are all set to the volume resistivity test position R v , the subsequent operation is the same as the measurement of surface resistivity; Then, the surface resistivity value of the test sample (29) is calculated according to the following formulas (1) to (2): ρ s and volume resistivity ρ v ; （1）； （2）； In the formula, ρ s is the surface resistivity of the sample to be tested (29), ρ v is the volume resistivity of the sample to be tested (29), resistance R N (35) is the known resistance value, I 1 is the electrode short circuit switch K 4 (10) Current value when closed, I 2 is the electrode short circuit switch K 4 (10) Current value when disconnected, d 1 is the diameter of the protected electrode (28), g is the distance between the protected electrode (28) and the protection electrode (27), S 1 is the actual thickness of the test sample (29) under pressure; Step 5: After the test is completed, unload the load, take out the electrode device (22), remove the sample to be tested (29), and clean the electrode device (22).

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