The requirements, standards and precautions of high and low temperature alternating damp heat test chamber are introduced in detail

Date：2021-07-26 16:02:00Views：1672

The service environmental conditions of high and low temperature alternating damp heat test chamber are as follows:

1. Temperature: 15 ℃ ~ 35 ℃

2. Relative humidity: no more than 85% RH

3. There is no strong vibration or electromagnetic field nearby

4. There is no high concentration of dust and corrosive substances nearby

5. No direct sunlight or other heat sources

6. There is no strong airflow nearby. When the nearby air needs forced flow, the airflow should not be blown directly to the box.

7. The test chamber shall be placed stably and kept horizontal.

8. A certain interval shall be reserved around the test chamber for routine maintenance.

9. The installation site is well ventilated

10. Single phase (220V 50Hz) or three boxes (380V 50Hz)

11. Various practical functional parameters of well grounded constant temperature and humidity test chamber

Requirements for high and low temperature alternating damp heat test chamber:

1. Prevent the condensation water on the wall of the high and low temperature alternating damp heat test chamber from dropping on the test piece.

2. The test chamber shall be provided with an exhaust hole to prevent the pressure rise in the chamber, and attention shall be paid to prevent external pollution.

3. Sensors and detection instruments: use solid sensors that are not affected by condensate to measure relative humidity, or use fast response dry and wet ball sensors or dew point testers. This test is a high relative humidity test, and sensors sensitive to condensate, such as lithium chloride sensor, shall not be used.

4. Data acquisition system is required to measure the test conditions, and the measurement system shall be equipped with appropriate recording device. The data acquisition system is generally separated from the controller of high and low temperature alternating damp heat test chamber. If a graduated recording paper is used, the recording paper shall be accurate to at least ± 0.6 ℃.

5. If the wet ball control method is adopted, the wet ball and container shall be kept clean, and the wet ball gauze shall be replaced with a new one before each test, and at least once on the 30th day. The wet ball gauze used shall be as thin as possible to facilitate water evaporation and keep the sensor surface wet. The water used in the wet bulb system shall be of the same quality as the humidification water.

6. If possible, the water container, wet ball gauze, sensor and other components constituting the relative humidity measurement system shall be visually inspected at least every 24 hours during the test to ensure the expected function.

7. Wind speed: the wind speed flowing through the wet ball sensor shall not be less than 4.6m/s, and the wet ball gauze shall be on the suction side of the fan to avoid the influence of fan heat. The wind speed at any part of the air around the test piece shall be maintained at 0.5m/s ~ 1.7m/s.

8. Humidification method: steam or water spray is used to humidify the air around the test piece. The water used for humidification shall meet the requirements of 3.2 in GJB 150.1a-2009. The water quality shall be inspected regularly (no more than 15d) to ensure that the water quality is qualified. If water spray is used for humidification, the water temperature shall be adjusted before water spray to avoid damaging the test conditions, and the water shall not be sprayed directly into the test area. During the test, the condensate generated in the test chamber shall be discharged from the test chamber.

9. Pollution prevention: except for water, there shall be no other substances in direct contact with the test piece to prevent deterioration of the test piece or affecting the test results. No rust or corrosive pollutants and other substances shall be introduced into the test chamber. The methods used for dehumidification, humidification, heating and cooling of the air around the test piece shall not change the chemical composition of air, water or water vapor in the high and low temperature alternating damp heat test chamber.

The high and low temperature alternating damp heat test chamber meets the following standards:

1. GB11158 technical conditions for high temperature test chamber

2. Gb10589-89 technical conditions of low temperature test chamber

3. Gb10592-89 technical conditions of high and low temperature test chamber

4. GB / t10586-89 technical conditions of damp heat test chamber

5、GB/T2423. 1-2001 test method of low temperature test chamber

6、GB/T2423. 2-2001 test method of high temperature test chamber

7、GB/T2423. 3-93 damp heat test chamber test method

8、GB/T2423. 4-93 alternating damp heat test method

9、GB/T2423. 22-2001 test method for temperature change

10. Iec60068-2-1.1990 low temperature test chamber test method

11. Iec60068-2-2.1974 test method of high temperature test chamber

12、GJB150. 3 high temperature test

13、GJB150. 4 low temperature test

14、GJB150. 9 damp heat test

Precautions for operation of high and low temperature test chamber:

1. According to the best installation site requirements provided by the supplier, prepare the placement environment of the laboratory. The factors to be considered are: the distance from adjacent walls or utensils; Ambient temperature and humidity of equipment; Whether the ground on which the equipment is placed is level; Whether there is good ventilation and avoid direct sunlight; Keep away from combustibles, explosives and high-temperature heat sources; Places with less dust; The place close to the power supply shall have standard power supply: three-phase five wire 380V / 50Hz.

2. In order to avoid safety accidents such as electric shock and equipment failure, please do not turn on the power supply until the installation and wiring are completed.

3. The wiring must be correct and grounded. If the grounding wire is not connected, it may lead to electric shock, abnormal equipment display or large measurement error.

4. During the test of high and low temperature test chamber, if there is no special need, do not open the door of the chamber, so as to avoid the unstable operation of the equipment and the damage of operators by high and low temperature.

5. The core control part of the high and low temperature test chamber is its control instrument. In order to ensure the reasonable and correct operation of the instrument and operate the equipment, please correct the instrument and maintain the whole equipment regularly.

6. The high and low temperature test chamber is a non explosion-proof product. During use, it must not be used for the test of the following substances or those containing them: nitroalcohol (ethylene glycol dinitrate), nitroglycerin (glycerol trinitrate), nitrocellulose and other explosive nitrates, trinitrobenzene, trinitrobenzene, trinitrophenol (picric acid) and other explosive nitro compounds Peracetic acid, methyl ethyl ketone peroxide, benzoyl peroxide and other organic peroxides and spontaneous combustibles.