Environmental Test Chambers for IEC 60068-2-78 Damp Heat
IEC 60068-2-78 shows us the method of testing samples in the specific temperature and humidity within a environmental test chamber. It is applicable to small equipment or components as well as large equipment, and can be applied to both heat-dissipating and non-heat-dissipating specimens.
The chamber and measuring system
1. The sensing device is necessary in the working place
2. Condensed water is drained from the chamber and not re-used unless purified
3. No condensed water from the walls and roof of the test chamber can fall on the specimen
4. The electrical conductivity of water utilized to maintain humidity is not more than 20μS/cm
5. The specimen can not be subjected to radiant heat and injected moisture from the chamber condition devices.
6. The volume of the test chamber is at least five times the total volume of the specimen under test
7. It should have the minimum influence on the heat and humidity exchange between specimen and surrounding conditions when the device is using
Severity
| Temperature ℃ | Relative humidity %RH |
| 30 ± 2 | 93 ± 3 |
| 30 ± 2 | 85 ± 3 |
| 40 ± 2 | 93 ± 3 |
| 40 ± 2 | 85 ± 3 |
The total temperature tolerance: ± 2K
Test procedure
1. The specimen shall be introduced in the unpacked, switched-off, ready-for-use state, or as otherwise specified in relevant specification.
2. CONDENSATION on the specimen shall always be AVOIDED. This can be obtained for small specimens by pre-heating them to the chamber temperature.
3. Adjust the temperature in the chamber to the prescribed severity. In order to avoid condensation on the specimen, control the specimen temperature or allow the specimen to reach the temperature first and then adjust the humidity in the chamber to the prescribed severity.
4. Adjust the humidity to the prescribed severity within a period of time of not more than 2 hours.
5. Expose the specimen to the test conditions and duration as specified in the relevant specification. The duration is measured from the time the specified conditions are achieved.
6. The relevant specification shall define the operating conditions and the period in which they shall be carried out.
7. After conditions at the prescribed severity and before the final measurement, the recovery procedure shall be followed.
Recovery procedure
Recovery conditions are described in IEC 60068-1.
Measurements
The specimen shall be visually inspected and electrically and mechanically checked, as required by the relevant specification.
The relevant specification
Preconditioning; initial measurements; details of mounting or supports; state of specimen( unpowered, powered, packaged, unpackaged, etc); type of specimen-heat dissipating or non-heat dissipating; test severities and tolerances( temperature, relative humidity, duration) ; intermediate measurements; recovery conditions; final measurements; any deviation in procedure as agreed upon between customer and supplier.
The relevant specification may call for measurements during the test procedure while the specimen is still in the chamber. If such measurements are required, the relevant specification shall define the measurements and the period at which they shall be carried out. For these measurements, the specimen shall not be removed from the chamber.
Our high and low temperature humidity climatic test chamber is designed according to the IEC 60068-2-78.
1. The specimen shall be introduced in the unpacked, switched-off, ready-for-use state, or as otherwise specified in relevant specification.
2. CONDENSATION on the specimen shall always be AVOIDED. This can be obtained for small specimens by pre-heating them to the chamber temperature.
3. Adjust the temperature in the chamber to the prescribed severity. In order to avoid condensation on the specimen, control the specimen temperature or allow the specimen to reach the temperature first and then adjust the humidity in the chamber to the prescribed severity.
4. Adjust the humidity to the prescribed severity within a period of time of not more than 2 hours.
5. Expose the specimen to the test conditions and duration as specified in the relevant specification. The duration is measured from the time the specified conditions are achieved.
6. The relevant specification shall define the operating conditions and the period in which they shall be carried out.
7. After conditions at the prescribed severity and before the final measurement, the recovery procedure shall be followed.
Recovery procedure
Recovery conditions are described in IEC 60068-1.
Measurements
The specimen shall be visually inspected and electrically and mechanically checked, as required by the relevant specification.
The relevant specification
Preconditioning; initial measurements; details of mounting or supports; state of specimen( unpowered, powered, packaged, unpackaged, etc); type of specimen-heat dissipating or non-heat dissipating; test severities and tolerances( temperature, relative humidity, duration) ; intermediate measurements; recovery conditions; final measurements; any deviation in procedure as agreed upon between customer and supplier.
The relevant specification may call for measurements during the test procedure while the specimen is still in the chamber. If such measurements are required, the relevant specification shall define the measurements and the period at which they shall be carried out. For these measurements, the specimen shall not be removed from the chamber.
Our high and low temperature humidity climatic test chamber is designed according to the IEC 60068-2-78.
There are sensors for temperature and humidity in the chamber. According to this standard, the condensation on the specimen shall be avoided. So we use evaporator to get the condensation rid of the specimen.
The water tank is placed at the lower right part of the chamber. It has automatic water shortage protection which is more convenient for customer to add water. The working room window is double glass, and it also has a small heater in it.
Why there is a heater in the window? When the inner is cold, the window will have frost on it. The heater used for getting rid of the frost on the window. The left side of the chamber is provided with test holes of 25mm or 50mm or 100mm in diameter. If you want more, you should let us know at the beginning of communication.
The refrigerator is TECUMSEH compressor from French. It has lower noise. And it have great very good refrigeration. We use strong air circulation to keep the steady temperature and humidity in the chamber.
When you are placing samples, you can not use all of the effective room. Because samples will block the air circulation, it may cause the unbalance of temperature and humidity.
The control panel is UNIQUE from Japan with a touch screen which is more convenient for customers to operate. The inner material of working room use SUS304 stainless mirror steel. It has good plasticity, toughness and corrosion resistance.
The outer material of chamber is A3 steel plate sprayed with plastic, which increases the appearance texture and cleanliness. In the meantime, the daily maintenance of chamber is the necessary way to extend service life of test chamber.
1. The ground placed the test chamber must be clean.
2. When you are taking out the test product from the box, do not allow the test product to contact with the door seal.
3. When the test time is over, you must cut the power of samples off, then take samples out of the chamber.
4. You need to clean the working room before testing samples.
5. The refrigeration system is the core of high and low temperature test chamber. You must check it out every half year.
6. The condenser should be maintained regularly every month. You can use a high pressure air nozzle blowing dust.
7. At the end of each test, it is recommended to clean the test chamber with clean water to keep the equipment clean. After cleaning the chamber, the chamber should be dried.
8. When the high and low temperature test chamber is not used during long-term shutdown, the equipment shall be powered up regularly every half a month, and the power supply time shall not be less than 1 hour.
9. Circulating air blades and condenser fans will condense a lot of dust and other small particles which should be cleaned regularly.
For more details, please feel free to contact sales@lenpure.com.
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