A device for testing the thermal conductivity of building materials
By using a linkage structure between the cylinder and the drive assembly to achieve synchronous action of the hot plate pressing and the clamping assembly, the problems of sample displacement and cumbersome operation in the existing technology are solved, and the accuracy and efficiency of thermal conductivity detection are improved. It is especially suitable for batch testing of building materials with large thickness differences.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GANSU HUILI ENGINEERING QUALITY INSPECTION CO LTD
- Filing Date
- 2025-08-30
- Publication Date
- 2026-07-31
AI Technical Summary
Existing thermal conductivity testing devices for building materials suffer from problems such as sample displacement due to the interval between actions during sample clamping and hot plate pressing, poor temperature field stability, and cumbersome operation. They are particularly unsuitable for batch testing of building panels with large thickness variations.
The system employs a linkage structure between the cylinder and the drive assembly to synchronize the pressing action of the hot plate with the opening and closing action of the clamping assembly. When the cylinder pushes the hot plate down, the rack and pinion drive gear rotates, driving the bidirectional screw to reverse the transmission, so that the clamping blocks automatically move together to complete the lateral clamping, ensuring a tight fit between the cold plate and the hot plate.
It achieves stable clamping of samples between cold and hot plates, quickly forming a uniform temperature field, improving the accuracy of heat flow monitoring and thermal conductivity calculation, and is suitable for batch testing of thermal insulation and fireproof boards that are sensitive to temperature fields.
Smart Images
Figure CN224581461U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of building engineering technology, specifically to a device for testing the thermal conductivity of building materials. Background Technology
[0002] Thermal conductivity is a key parameter for the thermal insulation and fire resistance performance of building materials (such as insulation boards and fireproof boards). Currently, the mainstream method used in the construction industry is the flat plate steady-state thermal conductivity meter based on the "temperature gradient method". The core of the meter includes a cold plate, a hot plate, and a clamping mechanism. During testing, the sample is fixed between the two plates to form a stable temperature field, and the thermal conductivity is calculated by monitoring the heat flow and temperature difference.
[0003] For example, Chinese patent CN221148566U proposes a thermal conductivity meter with an irregular clamping structure, which also falls under the category of flat steady-state thermal conductivity meters. It employs a dual-motor independent drive design. The first motor drives a bidirectional threaded rod to move a spring block to achieve lateral sample clamping, and the second motor drives a threaded rotating rod to adjust the height of the hot plate (the main body of the testing mechanism) to complete the downward pressing action. This solution requires two steps for clamping and hot plate movement. Not only is the interval between actions prone to sample displacement and disruption of temperature field stability, but operators also need to separately adjust the speed, direction, and other parameters of the two motors. The operation is cumbersome and difficult to adapt to the high-efficiency requirements of batch testing of building materials, especially for testing scenarios involving building panels with large thickness variations and frequent sample replacements. Utility Model Content
[0004] The purpose of this invention is to provide a device for testing the thermal conductivity of building materials, in order to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, this utility model provides the following technical solution: a building material thermal conductivity testing device, comprising a thermal conductivity meter and a clamping mechanism disposed on the thermal conductivity meter. The thermal conductivity meter includes a cold plate and a hot plate. The cold plate is disposed on the upper part of the outer shell of the thermal conductivity meter. The clamping mechanism includes two inverted U-shaped fixed seats disposed on the outer shell of the thermal conductivity meter and located on both sides of the cold plate, clamping components slidably disposed on the two fixed seats respectively, a cylinder disposed on one side of the outer shell of the thermal conductivity meter, and a driving component disposed on the outer shell of the thermal conductivity meter and located on one side of the fixed seats. The hot plate is connected to the output shaft of the cylinder and is located above the cold plate. The driving component is drively connected to the clamping component to drive the clamping component to open and close.
[0006] Furthermore, the clamping assembly includes sliding blocks that are horizontally slidably connected to two fixed seats, guide rods provided on opposite sides of the two sliding blocks, and clamping blocks that are slidably connected to the guide rods; a fastening bolt that cooperates with the guide rod is provided on one side of the clamping block, and an L-shaped rod is provided on the other side of the clamping block.
[0007] Furthermore, the drive assembly includes positioning seats on both sides of the upper part of the thermal conductivity measuring instrument housing and a bidirectional screw rotatably connected between the two positioning seats; a gear is provided in the middle of the bidirectional screw, and an L-shaped plate is provided on the cylinder below the hot plate. The vertical section of the L-shaped plate is a rack and meshes with the gear, and the vertical section of the L-shaped rod is threadedly engaged with the bidirectional screw.
[0008] Furthermore, each of the two clamping blocks has an opening on its opposite side.
[0009] This utility model achieves the following beneficial effects through structural innovation: 1. This utility model utilizes a linkage structure between a cylinder and a drive assembly to synchronously bind the pressing action of the hot plate with the opening and closing action of the clamping assembly. When the cylinder pushes the hot plate downward, the rack of the L-shaped plate synchronously drives the gear to rotate, driving the bidirectional screw to reverse transmission, causing the clamping blocks on both sides to automatically move towards the sample to complete lateral clamping; clamping is also completed synchronously when the hot plate reaches its position, with no action interval throughout the entire process. This fundamentally avoids the problem of sample displacement, ensuring a tight fit between the cold plate, sample, and hot plate, and can quickly form a stable and uniform temperature gradient, improving the accuracy of heat flow monitoring and thermal conductivity calculation. It is especially suitable for testing scenarios involving insulation boards and fireproof boards that are highly sensitive to temperature fields. Attached Figure Description
[0010] Figure 1 This is a structural diagram of the present invention; Figure 2 This is a rear view of the present invention.
[0011] In the picture: 1. Thermal conductivity meter; 2. Cold plate; 3. Hot plate; 4. Fixing base; 5. Cylinder; 6. Sliding block; 7. Guide rod; 8. Clamping block; 9. Fastening bolt; 10. L-shaped rod; 11. Positioning seat; 12. Double-acting screw; 13. Gear; 14. L-shaped plate; 15. Housing; 16. Display screen; 17. Control buttons. Detailed Implementation
[0012] The building material thermal conductivity testing device disclosed in this specific embodiment is based on the steady-state heat conduction principle of a flat plate using the "temperature gradient method." It aims to solve problems in existing technologies, such as sample displacement, poor temperature field stability, and cumbersome operation caused by the two-step operation of clamping the sample and pressing down the hot plate. The device achieves synchronous action and one-button operation, and is suitable for batch thermal conductivity testing of various building materials such as insulation boards and fireproof boards. This device mainly includes a thermal conductivity meter 1 and a clamping mechanism integrated thereon. The core function is to ensure the sample is stably clamped between the cold plate 2 and the hot plate 3 through the synchronous movement of the clamping mechanism and the hot plate 3, quickly forming a uniform temperature field. Finally, the thermal conductivity is calculated using the thermal conductivity meter 1. The thermal conductivity meter 1 adopts a flat, stable structure, including a cold plate 2, a hot plate 3, a display screen 16, control buttons 17, and an internal heating and temperature control system. The outer shell 15 is made of 304 stainless steel to ensure structural rigidity and corrosion resistance. The clamping mechanism is used to simultaneously achieve lateral clamping of the sample and vertical pressing of the hot plate 3. It includes an inverted U-shaped fixing seat 4, clamping components, a cylinder 5, and a drive component, all rigidly connected to the outer shell of the meter 1 to ensure operational accuracy. Its details are as follows: Cold plate 2 is an aluminum alloy plate measuring 300mm × 300mm × 10mm, with an internal serpentine cooling copper tube, and is fixed to the central area of the upper part of the outer shell of the thermal conductivity meter 1 by bolts. A 1mm thick thermally conductive silicone pad is attached to the upper surface of cold plate 2 to fill the tiny gap between the sample and the cold plate, ensuring uniform heat conduction. Hot plate 3 has the same dimensions as cold plate 2, an internal serpentine heating wire, and is located directly above cold plate 2. A thermally conductive silicone pad is also attached to the lower surface of hot plate 3, forming a symmetrical clamping surface with cold plate 2. The center of the upper surface of hot plate 3 is rigidly connected to the output shaft of cylinder 5 through a flange, and can move up and down vertically with the cylinder output shaft.
[0013] Two inverted U-shaped mounting bases 4 are integrally formed from aluminum alloy and are symmetrically fixed to the upper part of the outer shell of the thermal conductivity meter 1 by bolts, located on the left and right sides of the cold plate 2 respectively. The horizontal section of the mounting base 4 is provided with T-shaped or dovetail-shaped sliding grooves to accommodate the sliding block 6 of the clamping component, ensuring that the sliding block 6 can only move in the horizontal direction.
[0014] The clamping assembly is symmetrically distributed on two fixed seats 4 on both sides of the cold plate 2, used to clamp the sample laterally. It consists of a sliding block 6, a guide rod 7, a clamping block 8, a fastening bolt 9, and an L-shaped rod 10. The sliding block 6 is a rectangular metal block whose bottom is adapted to and embedded in the groove of the fixed seat 4, allowing it to slide horizontally along the groove. The surface of the sliding block 6 in contact with the groove is coated with polytetrafluoroethylene to reduce sliding friction. The guide rod 7 is a cylindrical stainless steel rod with a diameter of 8mm and a length of 120mm, vertically welded to the side of the sliding block 6 facing the cold plate 2 (i.e., the opposite side). The clamping block 8 is a metal block with an opening on one side, which has a through hole adapted to the guide rod 7. It is fitted onto the guide rod 7 and can slide laterally along the guide rod. The specific shape of the opening on the two clamping blocks 8 is determined according to the shape of the sample. The inner wall of the opening is coated with an anti-slip rubber pad (2mm thick) to avoid damage to the sample or sample displacement during clamping. The fastening bolt 9 is an M6 socket head cap screw, threaded to the side wall of the clamping block 8, with its end abutting against the outer wall of the guide rod 7; when tightened, it can fix the position of the clamping block 8 on the guide rod 7, and when loosened, it can adjust the position of the clamping block 8. The L-shaped rod 10 is a one-piece metal part, with the horizontal section welded to one side of the clamping block 8 and the vertical section extending downward, with an M8 internal thread at the bottom of the vertical section for mating with the drive assembly.
[0015] Cylinder 5 has a self-locking function and is fixed to one side of the outer shell of the thermal conductivity meter 1 by bolts through an angle steel bracket. It is powered and controlled by the electrical control box and control cabinet in the testing laboratory. The output shaft is vertically upward and rigidly connected to the hot plate 3 through a flange. The stroke of cylinder 5 is set to 120mm (which can be adjusted by the control cabinet), and the maximum output pressure is 0.5MPa, which ensures that the sample can be clamped while avoiding sample deformation under pressure.
[0016] The drive assembly converts the vertical motion of cylinder 5 into the horizontal motion of the clamping assembly, synchronizing the pressing down of the hot plate with sample clamping. It consists of positioning seats 11, a bidirectional screw 12, a gear 13, and an L-shaped plate 14. The two positioning seats 11 are rectangular metal blocks, bolted to both sides of the upper part of the outer casing of the thermal conductivity meter 1, located on one side of the fixed seat 4. Bearing holes are provided on the upper part of the positioning seats 11, housing deep groove ball bearings to support the bidirectional screw 12. The bidirectional screw 12 is a 400mm long, 10mm diameter metal rod, divided into left and right sections (bounded by the central gear 13), with opposite thread directions (left section left-handed, right section right-handed). Both ends of the bidirectional screw 12 are inserted into the inner rings of the bearings in the two positioning seats 11, achieving stable rotation around its own axis. The threads of the two sections respectively engage with the internal threads of the vertical sections of the two L-shaped rods 10. Gear 13 is a spur gear with a module of 2 and 20 teeth. It is fixed to the center of the double-acting screw 12 by a flat key and rotates coaxially with the double-acting screw 12. L-shaped plate 14 is a one-piece metal part. Its horizontal section is fixed to the output shaft of cylinder 5 by bolts or welding, and its vertical section extends downward. The inner wall of the vertical section is a rack that is adapted to gear 13. The rack meshes with gear 13 to ensure that when L-shaped plate 14 moves up and down with the output shaft of cylinder 5, it can drive gear 13 to rotate synchronously.
[0017] The working process of this utility model: 1. Check whether the power supply and cooling / heating system of the thermal conductivity meter 1 are normal, and whether the thermally conductive silicone pads on the surfaces of the cold plate 2 and hot plate 3 are intact (no damage, no stains); according to the sample thickness, loosen the fastening bolts 9 on the two clamping blocks 8, slide the clamping blocks 8 horizontally along the guide rod 7 so that when the openings of the two clamping blocks 8 clamp the sample, the hot plate 3 just presses the sample; after alignment, tighten the fastening bolts 9 to fix the position of the clamping blocks 8; set the detection parameters through the control buttons of the meter 1, and set the target temperature and temperature stabilization time for the cold plate 2 and hot plate 3.
[0018] 2. Cut the insulation board sample to be tested into a cube and place it stably in the center of the upper surface of the cold plate 2, ensuring that the lower surface of the sample is completely in contact with the thermally conductive silicone pad of the cold plate 2, without bubbles or displacement.
[0019] 3. The control cabinet drives cylinder 5 to start, and the output shaft of cylinder 5 extends downward, pushing the hot plate 3 vertically towards the cold plate 2. When the hot plate 3 moves down, the L-shaped plate 14 moves down synchronously. The rack of the vertical section of the L-shaped plate 14 meshes with the gear 13, and the downward movement of the rack drives the gear 13 to rotate. The rotation of the gear 13 drives the bidirectional screw 12 to rotate synchronously around the bearing in the positioning seat 11. Since the left and right sections of the bidirectional screw 12 have opposite threads, the two L-shaped rods 10 that are threaded together move towards the sample. The L-shaped rod 10 moves the sliding block 6 along the groove of the fixed seat 4, which in turn moves the guide rod 7 and the clamping block 8 to move closer to the sample until the anti-slip rubber pad of the clamping block 8 opening is tightly attached to the two sides of the sample (the clamping force is indirectly controlled by the cylinder pressure, about 0.2MPa), thus completing the lateral fixation of the sample; at the same time, the cylinder 5 pushes the hot plate 3 down, and the thermally conductive silicone pad on the lower surface of the hot plate 3 is completely attached to the upper surface of the sample. At this time, the cylinder 5 stops moving, and the sample is vertically clamped by the cold plate 2 and the hot plate 3.
[0020] 4. Then press the "Start" control button 17 on the thermal conductivity meter 1. The thermal conductivity meter 1 will start the cooling system of the cold plate 2 and the heating system of the hot plate 3 to form a stable temperature gradient on the upper and lower surfaces of the sample. After the temperature field stabilizes (the meter monitors the temperature of the cold and hot plates in real time, and the temperature difference fluctuation is determined to be stable if it is ≤0.1℃ / 10 minutes), the built-in heat flow sensor monitors the heat flow (Q) through the sample. The meter automatically calculates the thermal conductivity of the sample according to the Fourier steady-state heat conduction formula λ= Q×d / (A×ΔT). After the calculation is completed, the thermal conductivity value is displayed on the display screen 16, and the test report (including sample information, test parameters, calculation results, and temperature curve) can be exported via the USB interface.
[0021] 5. After the test is completed, the output shaft of the control cylinder 5 retracts upward, causing the hot plate 3 to move upward; simultaneously, the L-shaped plate 14 moves upward, the rack drive gear 13 rotates counterclockwise, the bidirectional screw 12 rotates in the opposite direction, and the two clamping blocks 8 move away from the sample, releasing the sample; take out the tested sample, clean the silicone pads on the surfaces of the cold plate 2 and the hot plate 3 (if there are stains), and repeat steps 1-4 to test the next sample.
Claims
1. A device for testing the thermal conductivity of building materials, comprising a thermal conductivity meter (1) and a clamping mechanism disposed on the thermal conductivity meter (1), wherein the thermal conductivity meter (1) includes a cold plate (2) and a hot plate (3), the cold plate (2) being disposed on the upper part of the outer shell of the thermal conductivity meter (1), characterized in that, The clamping mechanism includes two inverted U-shaped fixed seats (4) on the outer shell of the thermal conductivity meter (1) and located on both sides of the cold plate (2), clamping components that are slidably mounted on the two fixed seats (4), a cylinder (5) on one side of the outer shell of the thermal conductivity meter (1), and a driving component on the outer shell of the thermal conductivity meter (1) and located on one side of the fixed seat (4); the hot plate (3) is connected to the output shaft of the cylinder (5) and located above the cold plate (2), and the driving component is connected to the clamping component to drive the clamping component to open and close.
2. The detection device as described in claim 1, characterized in that, The clamping assembly includes sliding blocks (6) that are horizontally slidably connected to two fixed seats (4), guide rods (7) provided on opposite sides of the two sliding blocks (6), and clamping blocks (8) that are slidably connected to the guide rods (7); a fastening bolt (9) that cooperates with the guide rods (7) is provided on one side of the clamping block (8), and an L-shaped rod (10) is provided on the other side of the clamping block (8).
3. The detection device as described in claim 2, characterized in that, The drive assembly includes positioning seats (11) on both sides of the upper part of the thermal conductivity measuring instrument (1) and a bidirectional screw (12) rotatably connected between the two positioning seats (11); a gear (13) is provided in the middle of the bidirectional screw (12); an L-shaped plate (14) is provided on the cylinder (5) below the hot plate (3); the vertical section of the L-shaped plate (14) is a rack and meshes with the gear (13); and the vertical section of the L-shaped rod (10) is threadedly engaged with the bidirectional screw (12).
4. The detection device as described in claim 2, characterized in that, Both clamping blocks (8) have openings on opposite sides.