First, preparation stage:
Check the venting valve and butterfly valve at the bottom of the drying box, the upper water valve of the condenser, the intermediate overflow valve, the bottom drain valve, the hot air blower butterfly valve and the vacuum line venting valve, all should be in the closed position. Check if the oil level of the refrigeration unit and vacuum pump is normal and check if the Freon in the refrigerator is normal. Check that the submersible pump in the reservoir is completely submerged in water, if not immediately added water. Check the fuses and wiring screws for looseness.
Second, the operation phase:
1. Pre-cooling and pre-freezing:
Turn on the main power gate and turn on the water pump switch. Press the drying box cooling button on the drying device for 5 minutes, then press the drying box solenoid valve switch to gradually open the infusion main valve (red). When the temperature of the partition plate meets the temperature requirement of the product (below -30 °C), the product is quickly placed in the box, and each resistance thermometer is inserted into the sample at each position of the layer, and the door is pre-cooled. Generally, the temperature of the separator can be maintained below -30 ° C for stability, and the time is 2 to 3 hours to freeze and transfer to dryness.
2, dry:
Press the condenser refrigeration button to turn on the refrigeration unit (run for 2 minutes), dial the condenser solenoid valve switch, and gradually open the low pressure hand valve. The pressure of the low pressure gauge should not exceed 2Pa, and then open the high pressure hand valve to see that the pressure gauge cannot be greater than 2Pa. If the pressure is too high, close the solenoid valve or the hand valve to lower the pressure. After the condenser temperature is low below -50 °C, wait for 30 to 60 minutes, that is, press the vacuum pump button to start the vacuum pump. Before opening the vacuum pump, first turn off the dry box infusion main valve solenoid valve (wait 5 minutes), and the dry box cooling button is also turned off. System check on the condenser and vacuum line, then plug in the solenoid valve power, press the vacuum pump button, turn on the vacuum pump, slowly open the large butterfly valve between the drying box and the condenser to avoid a large amount of exhaust, and then turn on the vacuum pump set and The butterfly valve between the condensers, wait for the vacuum pressure to rise to 760mmHg and then open the two valves of the vacuum pump group every 1-2 minutes, unplug the power supply, and turn on the Roots pump. When the vacuum in the box meets the heating of the product, the vacuum is generated at 6 or more. After the moisture of the product is also drained, the circulation pump is gradually turned on to observe whether the vacuum is lowered, and then the fuel tank is heated. After the product temperature reaches 32 ° C ~ 35 ° C stability, the insulation is dried for 2 to 3 hours, the drying process can be ended.
3, stop deflation:
Close the tank heating, circulating oil pump, Roots pump, vacuum pump. Turn off the condenser solenoid valve, high pressure hand valve, make the machine run for 10 minutes, close the low pressure hand valve, and close the condenser button. Close the pump valve between the condenser and the pump set; turn on the condenser drain valve to deflate; open the intake valve at the front of the pump, vacuum the pump; remove the product.
4, defrosting:
When defrosting, the overflow valve and drain valve on the condenser must be opened first. The defrosting generally uses tap water, and flows into the condenser from the inlet valve to perform the rinsing. The defrosting is completed. After the water is discharged, the fan butterfly valve is opened and the fan is heated. Dry the water and cut off the total power.
Remark: The button on the console is turned on in green and disconnected in red; the small switch is up and down, and the down is off.
