Test block for calibrating quick freezing and thawing testing machine

Abstract

The utility model relates to the field of concrete detection and metering calibration, discloses a calibration test block of a concrete rapid freezing and thawing testing machine, and aims to solve the problems that a traditional test block needs to be maintained for a long time, and a sensor cannot be replaced and maintained. Comprising a test block body, a heat conduction sleeve, a joint, a lead pipe, a protective sleeve, a sealing cover and a corresponding mold. The heat conduction sleeve, the connector, the lead pipe and the protective sleeve form a sensor jack which is placed in a special mold to be poured into a test block. The test block and the temperature measurement sensor are mutually independent, the sensor is allowed to be taken out for maintenance or traceability after being used, and meanwhile, compared with a test block with a pre-embedded sensor, the test block has no obvious difference in response time of temperature measurement.

Description

Technical Field

[0001] This utility model relates to the fields of concrete testing and metrological calibration, and in particular to a calibration test block for a rapid freeze-thaw test machine for concrete. Background Technology

[0002] The rapid freeze-thaw testing machine for concrete is a commonly used concrete testing instrument in various building materials and construction site laboratories, used to test the freeze-thaw resistance of concrete. The national industry standard JG / T 243-2009, "Concrete Freeze-Thaw Testing Equipment," sets requirements for the temperature measurement and control performance of the rapid freeze-thaw testing machine and provides its testing methods. It mentions that concrete specimens with pre-embedded temperature sensors should be placed at the four corners and center of the freeze-thaw chamber. This raises three issues: First, the concrete specimens require curing, generally around 28 days, meaning calibration agencies need to prepare at least 28 days in advance, affecting work efficiency. Second, pre-embedding the sensors (usually platinum resistance thermometers) into the specimens means that the sensor's measurement value cannot be traced afterward, failing to meet the management requirements for a metrological standard. Furthermore, if the specimens break after multiple tests, new sensors must be purchased, and recalibration and specimen fabrication must be repeated, increasing operating costs. Third, conventional concrete specimens are prone to peeling or cracking after repeated freeze-thaw cycles, potentially altering their thermal conductivity and affecting the reliability of calibration results. Utility Model Content

[0003] To overcome the problems of existing technical solutions requiring the pre-fabrication of test blocks and the inability to trace the sensors within the test blocks, this utility model provides a calibration test block that does not require pre-embedded sensors. During calibration, sensors can be inserted into the test block for measurement, and after calibration, the sensors can be removed for maintenance and traceability.

[0004] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a test block for calibrating a rapid freeze-thaw test machine, comprising a test block body and a sensor socket. The sensor socket consists of a heat-conducting sleeve, a connector, a lead tube, and a protective sleeve. The heat-conducting sleeve is a pipe made of pure copper, closed at one end and inserted into the interface of the connector at the other end; the other end of the connector is inserted into the lead tube, which passes through the protective sleeve and extends beyond the test block through the threaded portion of the protective sleeve. After the sensor socket is pre-assembled, it is placed in a special mold, and concrete is poured in to form the test block. The sealing cap has an internal thread that matches the thread of the protective sleeve and is equipped with a sealing ring. After the test block is formed, the sealing cap is combined with the exposed threaded portion of the protective sleeve. In use, thermally conductive silicone grease is injected into the heat-conducting sleeve, and the sensor is inserted into the heat-conducting sleeve through the lead tube.

[0005] Since the sensor socket needs to be pre-embedded in the test block body, and the protective sleeve part exceeds the range of the rectangular block body, the special mold has an opening with a width matching the major diameter of the threaded part of the protective sleeve, and a baffle corresponding to the shape of the opening. The lower part of the baffle has a notch matching the major diameter of the threaded part of the protective sleeve. The baffle and the threaded part of the protective sleeve can be inserted into the opening to prevent concrete from flowing out of the mold during the pouring process.

[0006] The test block for calibration of the rapid freeze-thaw test machine mentioned above, the lead tube, connector, protective sleeve and sealing cap are all made of PTFE plastic.

[0007] Preferably, several fins of the same material are welded to the outside of the heat-conducting sleeve.

[0008] Preferably, the test block body is made of resin-based antifreeze mortar.

[0009] Optionally, the test block body can be directly cast into a thin-walled stainless steel box of the appropriate size and used as an outer shell.

[0010] The beneficial effects of this utility model are that, compared with the test block with pre-embedded sensors, the calibration test block of this utility model does not need to be made temporarily, the temperature sensor can be removed for replacement, maintenance and traceability, and it can prevent antifreeze from seeping in from the opening. It has a long service life and can be used repeatedly as equipment for a long time. At the same time, there is no significant difference in the response time of temperature measurement. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0012] Figure 1 This is a schematic diagram of the structure of this utility model.

[0013] Figure 2 for Figure 1 Top view.

[0014] Figure 3 This is a schematic diagram of a special mold structure.

[0015] Figure 4 This is an enlarged view of the opening of the special mold and a schematic diagram of the baffle.

[0016] Figure 5 This is a schematic diagram of a thin-walled stainless steel box and its assembly.

[0017] In the figure, 1. Test block body, 2. Heat-conducting sleeve, 3. Connector, 4. Lead tube, 5. Protective sleeve, 6. Sealing cap, 7. Sealing ring, 8. Special mold, 9. Opening, 10. Baffle, 11. Thin-walled stainless steel box. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Example 1: As Figure 1 As shown, a test block for calibrating a rapid freeze-thaw tester is disclosed. The test block includes a test block body 1 and a sensor socket. The sensor socket consists of a heat-conducting sleeve 2, a connector 3, a lead tube 4, and a protective sleeve 5. The heat-conducting sleeve 1 is made of pure copper, with one end closed and the other end inserted into the connector 3. The other end of the connector 3 is inserted into the lead tube 4. The lead tube passes through the protective sleeve 5, and the threaded portion of the protective sleeve 5 extends beyond the end face of the test block body 1.

[0020] In this embodiment, the sensor socket is pre-assembled and placed as follows: Figure 4 In the special mold 8 shown, the threaded portion of the protective sleeve 5 should be placed in the opening 9, and the baffle 10 should be inserted into the opening 9 to close the remaining portion. The threaded portion of the protective sleeve 5 is then combined with the sealing cap 6 to better secure the sensor insertion hole. Concrete is then poured in to form a test block. After the test block is formed, the sealing cap 6 and baffle 10 are removed, and the test block is taken out for routine curing. After curing, the sealing ring 7 is inserted into the groove of the sealing cap 6, and then combined with the exposed threaded portion of the protective sleeve 5. The sealing cap 6 can prevent antifreeze from seeping into the gap between the lead tube 4 and the test block body 1 during use, effectively extending the life of the test block. During calibration, thermal grease should be injected into the thermally conductive sleeve 2 before use, and the thermistor sensor is inserted into the thermally conductive sleeve through the lead tube 4.

[0021] Example 2: In this example, the test block body 1, sensor socket, etc. are no different from those in Example 1, but the original is no longer used. Figure 4 Instead of the mold shown, a mold like the one shown is used. Figure 5 A thin-walled stainless steel box 11 with internal dimensions of 100mm*100mm*400mm is used as a mold. Concrete is poured into the box, and a sensor socket is inserted. Then, a sealing cap 6 is screwed in, and the concrete is allowed to set. After molding, demolding is not required; the box is used directly as the outer shell of the test block. In this embodiment, the test block does not need to be cured in a curing chamber, and the test block has better durability under the protection of the thin-walled stainless steel box 11.

Claims

1. A test block for calibrating a rapid freeze-thaw test machine for concrete, characterized in that: include: The test block body (1), sensor socket and special mold (8) are composed of heat-conducting sleeve (2), connector (3), lead tube (4) and protective sleeve (5). The heat-conducting sleeve (2), connector (3), lead tube (4) and protective sleeve (5) are all embedded in the test block body (1). The lead tube (4) passes through the protective sleeve (5). The upper surface of the protective sleeve (5) is flush with the upper surface of the test block body (1). The threaded part extends outside the test block. The special mold (8) has an opening (9) that matches the major diameter of the threaded part of the protective sleeve (5). The baffle (10) also has a notch that matches the major diameter of the threaded part of the protective sleeve (5).

2. The calibration test block according to claim 1, characterized in that: The test block body (1) is made of concrete or resin mortar.

3. The calibration test block according to claim 1, characterized in that: The heat-conducting sleeve (2) is a pure copper tube with one end closed.

4. The calibration test block according to claim 1, characterized in that: When using, insert the temperature sensor into the sensor socket.

5. The calibration test block according to claim 1, characterized in that: It has a sealing cap (6) and an embedded sealing ring (7). After being assembled with the threaded part of the protective sleeve (5), the lower surface of the sealing ring (7) presses against the upper plane of the test block body (1).

6. The calibration test block according to claim 1, characterized in that: The connector (3), lead tube (4), protective sleeve (5), and sealing cap (6) are all made of PTFE plastic.

7. The calibration test block according to claim 1, characterized in that: The baffle (10) can be inserted into the opening (9) of the special mold (8), and after insertion, it is on the same plane as the inner wall of the special mold (8).

Images