Compression refrigeration type low-temperature brittleness tester

Characteristics and uses of compression refrigeration type low-temperature brittleness tester: The low-temperature brittleness tester is used to measure the high temperature at which a material fails under impact under specified conditions, which is the brittleness temperature. It can compare and evaluate the performance of plastics and other elastic materials under low-temperature conditions. It can determine the brittleness temperature and low-temperature performance of vulcanized rubber with different rubber materials or formulations. Therefore, quality inspection of scientific research materials and their products, control of production processes, and other aspects are indispensable. This instrument is designed according to the GB1682 national standard, and its technical indicators meet the requirements of national standards such as HG 2-162-1965 Plastic Low Temperature Impact Compression Test Method and GB5470-2008 Plastic Impact Brittle Temperature Test Method.
2, Technical parameters of compression refrigeration type low-temperature brittleness tester
1. Test temperature and time: -70 ℃ -0 ℃
Short cooling time, no need for water cooling, more environmentally friendly.
2. Impact velocity: 2m/s ± 0.2m/s
3. After constant temperature, the temperature fluctuation within 3 minutes of the experiment is less than ± 0.5 ℃, indicating more accurate temperature control.
4. Distance from the center of the impactor to the lower end of the gripper: 11 ± 0.5mm
5. Dimensions: 830 * 540 * 1260
6. Power: 800W. The power is smaller, and the compressor will automatically shut down after reaching the temperature, which is more environmentally friendly and energy-saving.
7. Volume: 3500 ml. Larger volume and wider testing range

3, Structural principle of compression refrigeration type low-temperature brittleness tester
3.1 Lifting gripper
The lifting gripper consists of a cylinder with a gripper and a cylinder seat.
The distance from the impacted part of the specimen to the lower end of the gripper is 11.0 ± 0.5mm, as shown in Figure 1.
3.2 Impact device
The impact device consists of an impactor and an impact cylinder.
3.3 Impactor
The shape and size of the impactor head are shown in Figure 2. The weight of the impactor is 200 ± 20g, and its working stroke is 40 ± 1mm. In the reset state of the impact cylinder, the distance from the end of the impactor to the specimen is 25 ± 1mm.
3.4 Freezing medium: Industrial ethanol
3.5 This measuring instrument uses a compressor for direct cooling No need for cooling circulating water.
4. Usage method
4.1 Connect the power supply, and the temperature controller and timer display lights will turn on.
4.2 Inject freezing medium (usually industrial ethanol) into the cold well, and the injection amount should ensure that the distance from the lower end of the clamp to the liquid level is 75 ± 10mm.
4.3 Vertically clamp the sample onto the gripper (as shown in Figure 1). The clamp should not be too tight or too loose to prevent deformation or detachment of the sample.
4.4 Press the gripper to start freezing the sample, and at the same time, activate the timing control switch (or press the stopwatch) for timing. The freezing time for the sample is specified as 3.0 ± 0.5min. During the freezing period of the sample, the temperature fluctuation of the freezing medium shall not exceed ± 1 ℃.
4.5 Lift the lifting gripper and allow the impactor to impact the specimen within half a second.
4.6 Remove the sample and bend it 180 ° in the direction of impact, carefully observing for any damage.
4.7 After impact (each sample is only allowed to be impacted once), if damage occurs, the temperature of the freezing medium should be increased. Otherwise, the temperature should be lowered and the test should continue.
Through repeated experiments, determine the low temperature at which at least two samples remain intact and the high temperature at which at least one sample fails. If the difference between these two results is no more than 1 ℃, the experiment is considered complete.
5. Test standards
5.1 Specifications
The length of the sample is 25.0 ± 0.5mm, the width is 6.0 ± 0.5mm, and the thickness is 2.0 ± 0.3mm.
5.2 Requirements
The surface of the sample should be smooth, free of foreign impurities and damage. The finished product should be polished and cut to the corresponding size.
6. Precautions
6.1 The cylinder pressure has been adjusted before leaving the factory and cannot be changed arbitrarily.