The thermal shock chamber is capable of simulating transient changes before high temperatures and low temperatures. It is generally used to determine if physical damage or performance degradation occurs when the equipment is subjected to drastic changes in ambient temperature. It is an essential test equipment for aviation, automotive, home appliances and scientific research. To assess and determine the parameters and performance of the complete machine and parts of testing instruments, machinery, electrical and electronic products after high and low thermal shock tests, suitable for aircraft flight exposure, air transport – desert exposure and ground or air – cold exposure.
Type of Thermal Shock Chambers
The structure of the thermal shock test chamber usually has the following three forms:
Firstly, three-box of the thermal shock chamber. The three-box type consists of a test area, a high temperature area, a low temperature area, a cold cabinet, and a control cabinet. The three-box structure requires a large amount of cooling and heating.
2. Vertical Lifting
Secondly, vertical lift type of thermal shock chamber. The vertical lift type consists of a high temperature zone, a low temperature zone, a gondola, a cold cabinet and a control cabinet. Because It is through the conversion of the basket lift. Therefore it is avoiding the influence of the external environment. However, due to the vertical installation in the high and low temperature zones, if the test space is large, the overall height of the test box is relatively high. Therefore it will result in the operation is inconvenient. Thus, this method is generally suitable for small test chambers.
3. Horizontal Mobile
Thirdly, horizontal mobile type of thermal shock chamber. The horizontal mobile type is also composed of a high temperature zone, a low temperature zone, a moving basket, a cold cabinet and a control cabinet, and is installed horizontally in a high temperature zone and a low temperature zone, and is suitable for a large test box.
Among them, the vertical lifting type and the horizontal moving type are two-box type thermal shock test chambers.
Above all things, the choice of test method should be divided according to the specific situation. The most economical test equipment is selected on the basis of ensuring that the test standards are met.
The Difference Between Thermal Shock Chambers
The differences of the three types of thermal shock chambers are shown in the following table:
|Three-box||Vertical lift||Horizontal mobile|
|Characteristics||Test area fixed|
High temperature and low temperature conversion in the same box
|Up and down two boxes|
High-temperature and low-temperature conversion through the basket moving up and down
|Left and right box|
High-temperature and low-temperature conversion by moving the basket left and right
|advantage||Test piece does not move|
No need for a basket conversion device
|Fast conversion time, less cooling capacity and heating required||Less cooling and heating required, easier temperature control|
|Disadvantage||When the temperature is raised and lowered, the requirements for pre-cooling and preheating are high, the power and energy storage devices are arranged in a large amount, and the cost is correspondingly increased.||For the medium and large test chambers, the basket device is not easy to implement, and the total height of the test box is high, which is not convenient for operation.||The basket drive device has higher requirements for high and low temperature resistance, and the moving rail has higher requirements for flatness.|
The three-box type is suitable for less demanding tests
|The vertical lift type is suitable for small devices||The horizontal mobile type is suitable for medium and large equipment|
The Characteristics of Thermal Shock Chamber
After understanding the differences of the three type of thermal shock chambers. Nextly, we mainly introduce the structural characteristics of vertical lift type thermal shock chamber.
The Cabinet of Thermal Shock Chamber
- The cabinet is made of sprayed galvanized steel, which is beautiful and beautiful.
- On the right is the control cabinet and the back is the refrigeration cabinet. There are two upper and lower doors in front, which are the high temperature test area and the low temperature test area.
- The insulation material is polyurethane foam + ultra-fine glass wool, which has good thermal insulation properties. The bottom is a channel steel structure with good load-bearing performance.
- In order to facilitate the movement and handling of the equipment, the base is equipped with casters and support feet.
The High Temperature Tank of Thermal Shock Chamber
- The high temperature tank is located at the upper part of the tank. Because high temperatures can change the physical properties or dimensions of the materials used in the equipment. Therefore, the materials used in the high temperature tank must meet the requirements for use in high temperature environments. It is made of 1.0mm thick SUS#304 high & low temperature resistance stainless steel, which is beautiful and durable.
- The front of the high temperature tank is a high temperature test area for use in high temperature tests or thermal shock tests.
- Behind the high temperature tank is a circulating air duct with a circulating fan, impeller and heating device. The air is heated inside and the airflow in the front test zone is circulated for cyclic testing.
- When the test sample is tested in the low temperature zone, the high temperature tank is in a heat storage state. And when the sample is moved from the low temperature zone, the high temperature test state can be restored in a short time.
The Low Temperature Tank of Thermal Shock Chamber
- The low temperature tank is located at the lower part of the tank. Because low temperature has an adverse effect on almost all matrix materials. Therefore, the materials used in the low temperature tank must meet the requirements for use in low temperature environments. It is also composed of 1.0mm thick SUS#304 high & low temperature resistance stainless steel, which is beautiful and durable.
- The front of the low temperature tank is a low temperature test area for use in low temperature test or low thermal shock test.
- Behind the low temperature tank is a circulation duct, equipped with a circulating fan, an impeller, a heating device, an evaporator and a regenerator. After the air absorbs heat through the evaporator, it reaches the low temperature required by the test, and the airflow in the test area and the air duct are mixed into one, and the cycle test is performed.
- When the test sample is tested in a high temperature zone, the low temperature tank is in a cold storage state. And when the sample is moved from the high temperature zone, the low temperature test state can be restored in a short time.
The Basket of Thermal Shock Chamber
- There are two sample racks inside the basket.
- The position of the sample holder is adjustable up and down. Besides, the bracket is composed of a SUS#304 stainless steel square tube.
- The top and bottom are sealed plates, which act to seal the high temperature zone and the low temperature zone. The sealing part is provided with a silicone belt. Moreover, it does not deform under high and low thermal shock conditions, and the sealing performance is good.
- The movement of the basket in the high and low temperature zones is driven by the cylinder. The cooperation of the cylinder, the wire rope and the roller is used to pull the basket to carry out the temperature impact test, thereby avoiding the disadvantages of the stroke of the conventional motor and the deformation of the casing.
- When the basket moves to the high temperature test zone, the tension between the lower part of the gondola and the high and low temperature zone is pressed by the pulling force of the cylinder to serve as a sealing function.
- When the basket moves to the low temperature test area, the separator between the upper part and the high and low temperature area is pressed by the self weight of the hanging basket to serve as a sealing function. The quality of the hanging basket seal directly affects the test performance.
As we konw, the use of thermal shock chamberis becoming more widespread. Choosing the right test equipment has a direct impact on the accuracy of the test. This article focuses on the vertical lifting type of thermal shock test chamber.
It has the ability to re-stabilize the test conditions within the test chamber within 5 minutes after the test piece is converted. It is worth mentioning that the conversion time of a sample from one studio to another is less than 10S, which is far beyond the requirements of the test standard.
Therefore, the vertical lifting type of two-box thermal test chamber has a fast conversion time and low test cost. It is the best choice for temperature test of small test pieces.