System Capability and Failure Analysis of High and Low Temperature Alternating Humid Heat Test Chamb

The high and low temperature alternating damp heat test chamber is a necessary testing equipment for aviation, automobiles, home appliances, scientific research and other fields. It is used to test and determine the temperature environment changes of electrical, electronic and other products and materials for high temperature, low temperature, damp heat or constant test After the parameters and performance. So, how is the temperature and humidity inside the high and low temperature alternating heat and humidity test chamber controlled?

1. Heating capacity

1. The heating device is the key link to control the temperature rise of the high and low temperature alternating damp heat test box

2. It is that when the controller gets the heating command, it will output voltage to the relay, about 3-12 volts DC is applied to the solid state relay; its AC terminal is equivalent to the wire connection; the contactor is also attracted at the same time, and there are two ends of the heater The voltage makes it generate heat, and the circulating fan drives the heat to the box, so that the high and low temperature alternating damp heat test box heats up.

3. The temperature will soon reach your set value; the controller can adjust on-off by adding a solid state relay

4. We use the high and low temperature alternating damp heat test box to see how much heating output is on the screen to adjust the heat; this is the temperature control above 89 degrees, how to control the temperature stability below 89 degrees? The constant temperature and humidity test box uses solid-state relays to generate heat on one side; the other uses the compressor refrigeration cycle to cool down to achieve dynamic equilibrium; the temperature is constant.

2. Cooling ability

1. An important part of the high and low temperature alternating damp heat test chamber is an important parameter to determine the performance of a constant temperature and humidity machine. It includes four major components: compressor, condenser, throttling device and evaporator.

2. The compressor is the heart of the refrigeration system. It sucks in low-temperature and low-pressure gas, turns into high-temperature and high-pressure gas, releases heat by condensing into a liquid, and takes away the heat through the fan. The low-pressure liquid then passes through the evaporator to become a low-temperature and low-pressure gas* and then returns to the compressor; the refrigerant absorbs heat in the evaporator to complete the gasification process and absorbs heat to achieve the purpose of refrigeration and complete the cooling process of a constant temperature and humidity machine.

3. Humidification capacity

4. Dehumidification ability

The dehumidification system is also completed by the refrigeration system, and the evaporator is placed in a constant temperature and humidity test box; relatively cold, high and low temperature alternating damp and heat test box, high humidity gas meets cold objects to condense into liquid; repeat the high humidity gas in the box There will be very little to achieve the purpose of dehumidification.

5. What does the damp heat test failure analysis refer to in the high and low temperature alternating damp heat test chamber?

*Common failure-humidification system

In the damp heat test, it appears that the actual humidity will reach 100% or the actual humidity is very different from the target humidity?

Analysis: It may be caused by the dryness of the gauze on the wet bulb sensor. Then check whether the water tank of the wet bulb sensor is lacking. The water level in the tank is automatically controlled by a water level controller. Check whether the water supply system of the water level controller is normal. , Whether the water level controller works normally. Another possibility is that the wet ball gauze will harden due to the long use time or the purity of the water supply, making the gauze unable to absorb water and dry. The above phenomenon can be eliminated by replacing or cleaning the gauze.

It appears that the actual humidity is very different from the target humidity, and the value is much lower?

Analysis: Mainly because the humidification system of the high and low temperature alternating damp heat test box does not work, check the water supply system of the humidification system, whether there is a certain amount of water in the water supply system, whether the water level control of the humidification boiler water level is normal, and whether the water level in the humidification boiler is normal.