Precautions for closed high and low temperature circulation device

The closed high and low temperature circulation device is a low temperature liquid circulation device with mechanical refrigeration.
It can be matched with a variety of instruments (rotary evaporator, chemical reactor, biopharmaceutical reactor, etc.
) to meet the actual needs of different users
.

What aspects should be paid attention to when facing the common faults of the expansion valve of the closed high and low temperature cycle device? 1.
If there is water in the refrigeration system of the equipment, it will dissolve in the refrigerant, and its dissolved amount is related to the temperature of the refrigerant.
The higher the temperature, the larger the dissolved amount, and the lower the temperature, the smaller the dissolved amount
.

When the refrigerant liquid flows into the expansion valve hole for throttling, it immediately cools down to the saturation temperature under the evaporation pressure, part of the water is precipitated, and the part attached to the valve hole will form an ice layer if the evaporation temperature is below 0.
When the ice layer increases , the valve hole is blocked
.

2.
When the operation is normal at the beginning, after a period of operation, the suction pressure drops rapidly to negative pressure (vacuum), the temperature rises, the frost layer melts (the frost layer of the suction pipe melts first), and the side ear cannot hear the flow of the expansion valve sound
.

At this time, it can be basically judged that the valve hole is blocked by ice or oil
.

　　3.
Keep the medium in a low concentration state.
After the medium is used for a period of time, the condensed water in the air will thicken in the medium at low temperature.
If the cold energy cannot pass through, the temperature will not drop.
If the medium is very thick at low temperature , if it cannot flow normally or freeze, the medium needs to be changed
.

　　4.
When there are too many impurities in the filter, the mesh is not very smooth or even completely blocked.
When tapping the inlet joint of the valve with the wrench handle, if the sound is louder than the original sound, it proves that the filter is extremely large.
If some of the meshes are seriously blocked, the sound of the refrigerant in the valve cannot be heard
.

　　5.
If the operation starts to pull the vacuum, the temperature will not drop at all, and the expansion valve does not have any airflow sound.
You can remove the expansion valve and remove the filter interface.
If it does not pass, it means that the valve hole is not open at all.
If it does not open, the expansion valve of the same type should be replaced
.

　　6.
Check whether the heat dissipation aluminum foil in the place that can absorb air after operation is dirty, and if so, clean it up
.

　　7.
Don't lean against the wall too tightly, leave enough ventilation space, keep the air circulating normally, and let the temperature dissipate to achieve the cooling effect
.