The vacuum drying oven is designed for drying heat-sensitive, easily decomposable and easily oxidizable substances. It can be filled with inert gas, especially for some complex materials, and it can be dried quickly. The author has learned that vacuum drying ovens generally have the following characteristics.
For example, the cuboid studio makes the effective volume reach the maximum, and the microcomputer temperature controller makes the control accuracy accurate and reliable. The tempered, bullet-proof double glazed door allows the operator to see objects in the workroom more clearly. In addition, the box can be closed tightly and can be adjusted. The integrally formed silicone rubber door seal can ensure high vacuum inside the box.
The vacuum drying chamber's studio is mainly made of stainless steel (or wire drawing) to ensure durability. Some manufacturers have indicated that the storage, heating, testing and drying of the vacuum drying oven are carried out in an environment free of oxygen, which is filled with an inert gas, so that it does not oxidize. Compared with the traditional vacuum drying oven, the heating time can be reduced by more than 50%.
However, vacuum drying ovens also have many problems during use. For example, the meter reading of the electric vacuum drying oven is different from the reading of the glass rod thermometer in the vacuum chamber. According to experts, the general electric vacuum drying oven adopts the method of heating the wall surface of the vacuum chamber first, and then radiating and heating the wall facing the workpiece.
In this heating mode, the temperature sensor of the temperature control instrument can be arranged on the vacuum outdoor wall, the sensor can accept convection, conduction and radiant heat at the same time, and the glass rod thermometer in the vacuum chamber will receive the radiant heat intelligently. In addition, due to the blackness of the glass rod, a considerable portion of the radiant heat is refracted. Therefore, the temperature value reflected by the glass rod thermometer is definitely lower than the temperature of the meter.
If the temperature sensing of the temperature control instrument is placed in the vacuum chamber, the difference between the temperature value of the glass rod temperature machine and the temperature reading of the meter can be reduced, but cannot be eliminated. The sealing reliability of the vacuum chamber adds a potentially unreliable link. If you do not want to see this difference from the perspective of operational applicability, you can use the display correction function unique to the temperature control instrument to solve it.
In addition, there are three main reasons why the vacuum drying oven is first vacuumed and then heated. First, the product is placed in a vacuum drying oven to evacuate the gas components that can be removed from the sample.
If the product is first heated, the gas expands when heated. It will be a potential threat to the sample. The cabinet of the vacuum drying oven is sealed, and the gas in the tank expands, posing a potential threat to the cabinet.
Second, if the vacuum drying oven is operated according to the procedure of heating up and then vacuuming, when the heated air is pumped out by the vacuum pump, the heat is inevitably brought to the vacuum pump, thereby causing the temperature of the vacuum pump to rise too high, and the efficiency of the vacuum pump is lowered.
Third, the heated gas is directed to a vacuum gauge, and the vacuum gauge produces a temperature rise. If the temperature rise exceeds the operating temperature range specified by the vacuum gauge, the vacuum gauge may cause an indication error.
The correct method of use of the vacuum drying oven should be followed by vacuuming and heating. If the vacuum drying oven has reached the rated temperature and it is found that the vacuum has decreased, it can be appropriately pumped. This is also advantageous for extending the service life of the vacuum drying oven.
The vacuum controller is configured to precisely control the vacuum of the vacuum oven. The vacuum controller can turn off the vacuum pump after the vacuum oven reaches the set vacuum. When the vacuum is reduced and the vacuum pump needs to be started again, the vacuum controller will start the vacuum pump again.
The vacuum controller not only precisely controls the vacuum of the vacuum oven. By controlling the intermittent start of the vacuum pump, the service life of the vacuum pump can be effectively extended.
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