Vacuum drying equipment at variable pressure method improves vacuum continuously during preheating stage.

Preheating stage of vacuum drying equipment with variable pressure method

When the core and the coil reach a certain temperature, the heat absorbed by the coil has decreased significantly, and a large amount of heat can be absorbed by the iron core with large heat capacity. At this time, the vacuum pump is opened, so that there is a certain degree of vacuum in the tank, and the moisture on the surface and shallow layer begins to evaporate. The vacuum is increased intermittently so that part of the evaporated water is pumped out of the tank and the other part participates in heat exchange as a heat transfer medium. As the evaporation of water takes away part of the heat and the pressure in the tank drops, the temperature of the body will drop. At this time, there should be enough heat to supplement the heat loss, so that the coil maintains a new heat balance to maintain normal temperature rise. In order to make the drying tank have good heat transfer conditions and ideal negative pressure evaporation effect, according to the physical characteristics of water in hot vacuum state, the pressure in the tank has an alternating process (evacuation-pressure-aeration-pressure-vacuum).

Electronic control system

1) The power supply of the vacuum drying equipment with pressure swing method is special for the equipment. It is forbidden to connect any electrical equipment unrelated to the equipment.

2) it is forbidden to connect other devices or lines to the control cabinet or components of the equipment.

3) it is forbidden to place any articles in the control cabinet to prevent fire, short circuit, electric shock and other hazards.

4) prohibit non professional personnel from opening the cabinet cabinet door during the operation of the equipment to prevent electric shock. 5) prohibit changing the setting time of relay in control cabinet.

If it is found that the heating ammeter still has a numerical value indicating the system is not heated by the program, it should be checked immediately if the contactor is damaged and replaced immediately if the contactor is damaged; if one or two ammeters show no numerical value during heating, it should be checked immediately if the fuse is damaged, if it occurs. The fuse damage should be replaced in time.

The top of the heat conduction tank is the heater terminal. It is forbidden to place articles. If you need to move the cover plate, you must make sure that the heating cabinet is in a state of power failure. Always check the running state of the heat conducting oil system. The pressure gauge 910 should not be less than 0.2 Mpa to prevent the partial overheating of the oil tank caused by the heat conducting oil flowing in the oil tank due to the idling of the oil pump or poor circulation.

The manual valves (except blowdown valves) of the heat transfer oil system should be in a normally open state. It is forbidden to change the installation position and height of the heat resistance on the heat conducting oil heating box and prevent temperature deviation. _8) It is forbidden to modify the setting value of the temperature control meter on the control cabinet without permission, so as to prevent the malfunction of the temperature measurement and protection function, or the occurrence of misoperation.

Note: If the tank needs to be heated in an atmospheric state, 203 valves must be opened before heating and the door must not be clamped. Prevent the tank from being damaged by pressure rising.

Always check the fuse, contactor and heater wire status, if there is damage or loose phenomenon, should be replaced in time, fasten.