Common causes and troubleshooting methods of vacuum freeze dryer
Vacuum freeze dryer
Vacuum freeze-drying is the process of freezing a solid substance containing a large amount of water, and then freezing it to a solid, and then sublimating the water vapor directly from the solid under a certain vacuum condition. The substance itself remains in the ice shelf when it is frozen. After drying, the volume does not change. The loose porous ice absorbs heat during sublimation, causing the temperature of the product itself to drop and slow down the sublimation speed. In order to increase the sublimation speed and shorten the drying time, the product is subjected to Heat properly. The entire drying process is carried out at a lower temperature.
The vacuum is not high:
cause:
1. The pump temperature is too high. It may be that the valve or inner cavity of the pump is scratched and worn, and the rotor shaft is displaced to cause single-sided wear.
2, the pump oil has problems: 1, the oil level is too low, the seal is not strict; 2, the oil is contaminated with milky yellow; 3, the oil level is normal, the oil path is not available, the pump cavity does not maintain the proper amount of oil.
3. The pump itself leaks: the seal ring and the gas ball valve gasket are damaged or not pressed, and the exhaust valve piece is damaged, resulting in poor sealing.
4. The air inlet filter is blocked.
Method of exclusion:
1. Reassemble after repair.
2, refueling; oil change; check the oil and oil valve oil intake.
3. Replace the seal ring or valve plate for specific conditions.
4. Remove and clean.
The motor is overloaded, there is abnormal noise and noise during pump operation, and it is difficult to rotate.
cause:
1. The pump temperature is too high. It may be that the valve or inner cavity of the pump is scratched and worn, and the rotor shaft is displaced to cause single-sided wear.
2. The spring is deformed or broken, so that the rotating piece is not evenly stressed and emits impact sound.
3. The filter is damaged and the debris falls into the pump.
4. The pollution in the pump chamber is serious and the parts are rusted.
5. The pump cavity shaft and the sleeve are too tight, resulting in poor lubrication.
Method of exclusion:
1. Reassemble after repair.
2. Replace the spring.
3. Remove and clean.
4. Change the oil.
5. Reassemble and unblock the oil circuit.
Oil spill, fuel injection
cause:
1. The sealing ring of the shaft, oil window, oil drain hole, etc. is damaged or incorrectly assembled.
2. The inlet pressure is too high.
3, too much oil, resulting in fuel injection.
4. The oil retaining net under the exhaust cover is reversed, causing fuel injection.
Method of exclusion:
1. Replace the seal or reassemble.
2. Try to reduce the amount of oil.
3. Release some of the oil.
4. Reassemble.
The motor does not start up
cause:
The power supply is unreachable and the voltage is too low.
Method of exclusion:
According to the instructions, turn on the power, and the voltage is normal to reset the relevant contacts.
The motor can't move
cause:
Because the chiller load is too large, far exceeding the rated power of the motor, causing the compressor to not run or the operation to slow down significantly, and the motor beeps, immediately turn off the power for inspection.
Method of exclusion:
Check if the three phases have electricity and the power supply voltage is normal.
Water pressure alarm shutdown
cause:
The cooling water pressure of the water condenser is lower than the set value of the water pressure relay, and the compressor automatically stops.
Method of exclusion:
Alarm, check the water pipe, restore the water pressure to normal, and restart the compressor.
Oil pressure difference alarm shutdown
cause:
1. The oil return is not smooth, resulting in insufficient oil level in the crankcase of the compressor, and the oil pump can not absorb oil.
2. The oil is dirty and the oil pump filter is clogged.
3. The oil pressure difference relay is out of order.
Method of exclusion:
1. Replace the new oil separator.
2. Change the oil and clean the oil filter.
3. Replace the new oil pressure difference relay.
High pressure alarm shutdown
cause:
1. Too much refrigerant and high exhaust pressure.
2. The cooling water temperature is high, the flow rate is insufficient or the water condenser is fouled.
3. There is leakage in the low-pressure section of the refrigeration pipeline, and the air is taken in.
4. The high pressure exhaust valve is not open or damaged, resulting in poor exhaust.
Method of exclusion:
1. Release part of the refrigerant.
2. Use the cooling water temperature and flow rate to meet the requirements and clean the water condenser.
3. Refrigeration pipeline leak detection.
4. The high pressure exhaust valve opens or replaces the new valve.
Motor thermal protection shutdown
cause:
The system has insufficient air return and the motor is not sufficiently cooled.
Method of exclusion:
1. Adjust the expansion valve to increase the circulation of the system to fully cool the motor;
2. Check if the liquid supply pipeline is clogged (the liquid supply shut-off valve, the drying filter, the solenoid valve, the filter screen before the expansion valve) is blocked. If the blockage occurs, it should be solved accordingly.
3. Check the suction filter of the return air line and the compressor for blockage and blockage for repair.
4. Check for the lack of refrigerant. If the refrigerant is missing, replenish the refrigerant.
Condenser performance deteriorates
cause:
1. The condenser defrosting is not complete, which makes the heat transfer performance worse.
2. The product load exceeds the set value.
3, the product sublimation heating is too large, sublimation is too fast.
Method of exclusion:
1. Defoam thoroughly and drain the water.
2. Do not exceed the maximum catch.
3. Slow down the heating speed.
Insufficient cooling capacity or no cooling capacity
cause:
1. The expansion valve is opened too much. At this time, the temperature of the shelf or the steam condenser does not drop to the set value, and the compressor frost is severe.
2. The expansion valve is too small to open, at which time the temperature does not drop, but the compressor temperature is very high, the suction valve is not frosted, and the suction pressure corresponds to the evaporation temperature of the shelf or the water vapor condenser than the shelf or water vapor. The temperature of the condenser is much lower.
3, the refrigeration system is not blocked, such as filter blockage, valve is not open, solenoid valve failure, expansion valve blockage.
4. The refrigerant is insufficiently filled. At this time, the temperature does not drop, and the suction pressure is low, and the inhalation valve is not frosted.
5. The paper pad on the upper part of the compressor valve or the lower part of the cylinder is broken or broken, or the suction and exhaust valve pieces of the compressor are broken.
Method of exclusion:
1. Adjust the expansion valve.
2. Unblock the refrigeration system to replace parts.
3. Fill the refrigerant.
4. Replace the paper pad or valve.
Low heat transfer oil pressure
cause:
There is air in the heat transfer oil.
Method of exclusion:
Turn on the circulation pump, one end of the hose is connected to the heat transfer oil exhaust port, one end is connected with the balance tank, and the exhaust valve is opened to dispose of the air in the road.
Large temperature difference between heat transfer oil inlet and outlet
cause:
1. The flow of the heat transfer oil is insufficient (the performance of the heat transfer oil decreases and the performance of the circulating pump decreases).
2. The temperature probe is faulty.
3. Air is mixed with heat transfer oil.
Method of exclusion:
1. Change the heat transfer oil and repair the circulating pump.
2. Replace the temperature probe.
3. Drain the air.
Circulating pump switching
cause:
1. The pressure is unstable.
2. The circulation pump is damaged.
3. The pressure relay has been damaged.
Method of exclusion:
1. Drain the air.
2. Replace or repair the circulation pump.
3. Repair or repair the relay.
Zhejiang Sealand Technology Co., Ltd. is a trustworthy manufacturer of Natural Gas Mass Flow Meter, Natural Gas Mass Flowmeter, Natural Gas Coriolis Meter, Natural Gas Coriolis Mass Flow Meter, ATEX, IECEx & CE approved.
First, Sealand meter is certified by Zhejiang Institute of Metrology. To get such certificate, Sealand has to send all models to Zhejiang Institute of Metrology and all models are tested in their calibration lab. The lab is an ISO/IEC 17025:2005 standard lab approved by CNAS (China National Accreditation Service for Conformity Assessment). CNAS is a member of ILAC (International Laboratory Accreditation Cooperation).
Second, Sealand has its own calibration lab, equipped with METTLER TOLEDO scales with accuracy 0.014% and the device extended uncertainty is 0.05%. The lab is also approved by Zhejiang Institute of Metrology. This certificate will stay valid only for one year, Zhejiang Institute of Metrology will send their professor to Sealand every year to check and make sure that the lab is qualified still and then issue new certificate. During the production, each meter will be calibrated in this lab for 3 times, each time at 5 different flow rate.
Finally, Sealand also gets ISO, CE, SIL, ATEX & IECEx. Sealand is the only Chinese brand who gets ATEX & IECEx and it is from TUV SUD ( the most authoritative institute for ATEX).
Natural Gas Mass Flow Meter, Natural Gas Mass Flowmeter, Natural Gas Coriolis Meter, Natural Gas Coriolis Mass Flow Meter
Zhejiang Sealand Technology Co., Ltd. , https://www.sealandflowmeters.com