Troubleshooting: How to set the index of the high-low temperature damp heat test box?

Troubleshooting: How to Set the Indicators for a High-Low Temperature Humidity Tester

Frequently, some customers have asked about how to set the index of the high-low temperature damp heat test box, and put forward the following suggestions for setting the indicators of the high-low temperature damp heat test box:

(a) temperature range

High temperature: Since the grade of GB/T2423 is 155°C at 125°C, there is no difference between high and low temperatures of 150°C and 130°C. It is recommended that the nominal temperature be 150°C, the temperature field test index be at 125°C or 130°C, and the temperature field test index be reflected in the technical agreement. The sample may not be described.

Cryogenic: The lowest temperature occurs in the MIL-STD-810F method 502.4:-61°C and is not required. GJB150.4-86: -55°C. The GB/T2423 grades are +5, -5, -10, -25, -40, -55, -65°C. According to the characteristics of the refrigeration system, the low temperature can be set according to the current scope, but only a little marketing changes can be made. Overlays increase by -60°C and are elastically configured according to the selling price. 13428419795 Li Meng

(B) configuration recommendations ()

1) High and low temperature damp heat test box temperature rise and fall characteristics:

Heating and cooling temperature configuration should be between 1°C/min~3°C/min and the starting temperature is 130°C. 150 ~ 130 °C does not open refrigeration, because the product may be used for heat load test, if the Qidong compressor balance is unfavorable to the refrigerant at a constant temperature higher than 130 °C, the product may be damaged.

2) Humidity characteristics

GB/T2423.34-2005 is cooled from 25 (93% RH) to 30°C for less than 30 minutes and kept at a constant temperature for 3 hours. GJB630A-96 method at 10625±2°C (90~100%RH) and -10±2°C for 15 minutes. In addition, the relevant standards for photovoltaic test have similar wet-frozen requirements. Our product configuration can be achieved and we can highlight it.

3) Wind speed characteristics

From the damp heat box, the wind speed should be controlled at 0.5~1m/s. In the current standard box air duct, the fan configuration is basically around 1m/s, and the evaporator can be magnified to a non-standard cooling rate of ≤ 3°C/min. For fast temperature changes, if you want to amplify the fan blades, the wind speed may be greater than 1m/s. For fast temperature tapering products, the traditional method is to add inverters. It can be considered to add 380/220V three-phase transformer switching, reduce the configuration cost, and do not reduce the reliability of the product, but also to avoid the power supply pollution caused by the inverter.

4) Noise

The acceptable index of noise is ≤ 70dB. At present, it is basically impossible to achieve further control of noise.

5) Control

The starting point of cooling is 130°C.

(c) Lifting and cooling rate

According to the conditions of new technology, as the test method for raising and lowering temperature is clarified, the index of temperature rise and fall can be changed from the current temperature interval time mark to the speed mark, and the standard box is ≥1°C/min (according to the implementation standard, 80% of the range, Do not specify on the sample, indicate on the technical agreement), and give different indicators (European model) according to the different models of the standard box product configuration. In fact, Espec's index is due to its products can not do the whole process of cooling, unable to give full cooling targets.

(d) Humidity range

High temperature and humidity: 95%RH/65°C, 85%RH/85°C

Low temperature and high humidity: 98%RH/25°C, 95%RH/20°C

Low temperature and humidity: 50%RH/25°C, 50%RH/23°C

The humidity range coverage diagram should include the above indicators, and the current low temperature part of the coverage map can be extended from 25°C to 20°C. At present, the production capacity is fully achievable.

Due to the problem of the service life of the solenoid valve, the cycle of cold output should be appropriately extended, and it is recommended that it can be extended to 12~15 seconds.

When the humidity and heat are constant (including the alternating constant temperature section), the wet bulb temperature will fluctuate with the fluctuation of the dry bulb temperature, not the humidity fluctuation. Based on our current control value and humidity calculation, the wet-bulb tracking method compares the dry-bulb setting target value, and the steady-state humidity control actually overcomes the humidity calculation fluctuation caused by the temperature fluctuation. It is recommended that the control value humidity be calculated on the dry-bulb measurement value. When entering the range of ±0.5°C (or other value, or over time delay) from the set value difference, the wet-bulb tracking is compared with the dry-bulb measurement value.

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