What is a dehumidifying dryer?Dehumidifying dryers are generally used in industrial production to dehumidify and dry raw materials with strong hygroscopicity to ensure high-quality product forming rates. In the past, companies used traditional hot air blowers. If they encounter wet weather, the hot air blowers can hardly complete the drying purpose. The dehumidifying dryer came into being to improve the disadvantages of hot air blowers!
1. Traditional hot air blower In order to evaporate the moisture in the material, the traditional hot air blower will use the hot air heated by electric heating to dry the material at high temperature. However, due to weather factors, dry weather and humid weather, the moisture content in the air will be different, and the drying effect will also be different. In traditional hot air blowers, electric heating must first heat the incoming air. If the weather is too humid and the incoming air contains high moisture, it is difficult for the material to dry.
2. Dehumidifying dryer Dehumidifying dryer effectively improves the shortcomings of ordinary dryers. It first draws in ambient air to remove moisture in the air under low dew point, and then heats the dried air to the dryer to dehumidify and dry the material. , Improve the work efficiency to a large extent, reduce the drying time, and the drying effect is better. The air pipeline of the dehumidifying dryer adopts a closed circulation system, which can not be affected by the outside weather, and the material can be dried well in dry or humid days without reversing moisture. The filter installed in the dehumidifying dryer can prevent dust leakage from causing pollution in the factory and keep the air environment clean. Generally speaking, the difference between these two dryers is that the moisture content of the inlet air used for drying is different. One has processed the inlet air moisture, and the other has not processed the inlet air moisture.
Why use dehumidifying dryer:In the plastics processing industry, products appear shrinkage, silver streaks, bubbles, cracks, flow marks, poor transparency, etc. The main reason for these poor quality is that the plastics are not fully dried before they are molded. Engineering plastics such as : PA, PET, PC, PBT, CA and other materials with strong hygroscopicity, due to the penetration of water into the plastic particles, traditional hot air dryers cannot completely dry them. Practice has proved that reducing the dew point of the drying wind to below -40°C and controlling the heat to blow it over the surface of the wet plastic particles can reduce its moisture content to below 0.02% before molding. The three-machine dehumidifying dryer is airtight. The air is fully dehumidified and heated in the circulation system, and the dry air quickly completely separates the moisture in the plastic particles to achieve the effect of dehumidification and drying.
Principle of dehumidifying dryer:Dehumidification and drying part: The hot and humid air coming back from the drying barrel is cooled and blown into the honeycomb runner. The moisture in the air is adsorbed by the runner and then desorbed by the regenerated heated air. The two airflows act on the runner at the same time, and as the runner rotates, the moisture in the air is continuously adsorbed and desorbed by the regeneration air to be discharged, forming a stable low dew point air, which is heated to the plastic The drying temperature is blown into the drying barrel to form a closed loop to dry the raw materials.
Suction part: Suction is sucked into the dry bucket from the storage bucket or other storage bin containers. When the reed switch of the vacuum hopper detects that there is no material, the suction motor runs to generate a vacuum in the vacuum hopper. The raw materials in the storage bucket are sucked into the vacuum hopper due to the air pressure difference. When the suction time is completed, the suction motor stops running, and the raw materials fall into the drying bucket due to their own weight. The dried raw materials are pumped from the drying barrel to the electric eye hopper installed in the plastic molding machine.
The internal circulation of the dehumidifier: Through the operation of the compressor → discharge high-temperature and high-pressure gas through the exhaust port → enter the condenser for cooling → become a low-temperature and high-pressure gas → intercept the flow through the capillary tube → become a low-temperature and low-pressure liquid → evaporate and absorb heat through the evaporator → Return to the compressor to become a low-temperature and low-pressure gas. So it goes back and forth.
The external circulation of the dehumidifier: under normal startup → through the operation of the fan → inhalation of moist air from the air inlet → pass through the evaporator → the evaporator absorbs the moisture in the air on the aluminum sheet → becomes dry air → passes Condenser heat dissipation → blow out from the air outlet.
Features of dehumidifying dryer: 1. Dehumidification by adsorption wheel
The thin plate impregnated with hygroscopic agent is processed into a honeycomb wheel for ventilation to achieve the dehumidification effect.
2. Liquid absorption dehumidification
There are two types of liquid absorption dehumidification, one is to use the spray of lithium chloride aqueous solution to absorb water and adsorb it on the solid moisture absorbent, which can reduce the dew point, but the equipment becomes larger when the adsorption area is large. It can be lowered to about, but the equipment is larger, and the absorption liquid must be replaced; the other is to use capillary action to remove water!
3. Compression and dehumidification
Compress and cool the moist air to separate its moisture to achieve dehumidification effect. Need to pay attention
Yes, this kind of dehumidification method is effective in small air volume, but it is not suitable for large air volume.
4. Cooling and dehumidification
The air is cooled to below the dew point, and then the condensed moisture is removed to achieve the dehumidification effect. This method is effective when the dew point is above
1. It integrates three functions of dehumidification, drying and two-stage feeding;
2. The dehumidification part is equipped with a wheel device, which can provide stable and low dew point air, and the dew point can reach below -40℃;
3. The stainless steel double-layer thermal insulation drying barrel adopts the design of lower blowing pipe to make the raw materials evenly dry and effectively prevent heat loss;
4. The feeding system is equipped with a shut-off valve to ensure that there is no residual raw material in the material pipe;
5. The closed loop feeding system can prevent the raw materials from being polluted or re-moisture;
6. The optical grade GCD-OP model is matched with a boiling electric eye hopper, which can remove the fine powder in the raw material, and can avoid pollution
Point generation;
7. The optical-grade GCD-OP model system is equipped with high-precision and high-efficiency filters, which can effectively filter dust ions up to 0.3μm, and the filtration rate is up to 99.9%;
8. PLC control with LCD touch-sensitive man-machine interface can be purchased, the operation is centralized and convenient, and the whole machine can be controlled to run automatically;
9. Dew point detection device can be purchased;
Dehumidifying dryer models:
Application of dehumidifying dryer:Suitable for engineering plastic materials with strong moisture absorption. Such as PA, PET, PC, PBT, etc., among which optical grade GCD-OP models can be used in the manufacturing process of optical grade products such as lenses, LCD light guide plates, optical discs, etc. The lowest dew point can reach -40℃ under ideal conditions .
Operation guide for dehumidifying dryer:1. Purpose
Properly operate and maintain the Dehumidifying dryer and standardize the operation of the PA11 dehumidifying dryer to ensure the baking quality of raw materials, increase the service life of the machine, and protect the safety of operators.
2. Scope It is applicable to the operation of all desiccant dryers in our factory.
3. Definition None
4. Operational Responsibilities The feeder in the injection molding department uses the dehumidifier and dryer correctly in accordance with this operating instruction to protect the dehumidifier from damage and normal operation, and ensure that the machine is clean and tidy.
5. Content
5. 1 Put all the current disconnect switches in the control box to the "ON" position, press the RUN/STOP key on the control panel, the indicator light will light up to start operation, and press RUN/STOP again during operation. ] Key, the indicator light flashes slowly, cooling operation, it will shut down after 5 minutes of operation.
5. 2 Setting of drying temperature: Press the mode switch【MOKE CHANGE】key twice, at this time the drying temperature setting display shows the symbol of C unit, press
5. 3 One-time conveying operation: press the LOADRI RUN/STOP] key of conveying 1 and the material is sent from the storage bin to the drying barrel. At this time, the indicator light flashes quickly, and when conveying 1 is pressed again, the operation will start. /Stop【LOADRI RUN/STOP】key, the indicator light flashes slowly until it stops, when the indicator light does not flash, it means that the bucket is full.
5. 4 Secondary conveying material operation: press the LOADRI RUN/STOP button of conveying 2 to send the material from the drying barrel to the machine storage hopper. At this time, the indicator light flashes quickly. When conveying 2 is pressed again Run/stop] LOADRI RUN/STOP] key, the indicator light flashes slowly until it stops, when the indicator light does not flash, it means that the bucket is full.
5. 5 The three-time conveying operation is the same as the second-time feeding operation mode, but the key is the conveying 3 run/stop]LOADRI step RUN/STOP] key.
5. 6 When Dehumidifying dryer is automatically operated to transport materials from the storage box to the drying cylinder and from the drying cylinder to the hopper of the forming machine, the conveying must be opened first
5. 8 Maintenance and maintenance of desiccant dryer:
5.8.1 dehumidifying dryer delivery 1-3 Filters and dryer filters must be cleaned once every shift.
5.8.2 When the machine is maintained and repaired, all current switches in the control box must be set to the "OFF" position.
5.8.3 The material in the PA11 dehumidifying dryer can only be used by the random molding machine (except for special circumstances).
5.8.4 When conveying 2 (transporting 3) is in operation, pay attention to opening the drying cylinder unloading valve about half to prevent the remaining material in the conveying pipe from blocking the conveying pipe and affecting feeding when the conveying 2 (conveying 3) stops.
5.8.5 The machine will generate high temperature during operation. Please take care to prevent burns. Do not touch the operation panel with wet hands, otherwise electric shock may occur. Note: The PET material of Hexing Parts must be produced with this machine, and other materials must be produced with a dehumidifying dryer according to the physical property table.
6. Reference file "Dehumidifying dryer operation manual"
7. Relevant records Dehumidifying dryer drying material record sheet Dehumidifying dryer maintenance check sheet
Maintenance of dehumidifying dryer：Practice has proved that reducing the dew point of the drying wind to below -40°C while controlling the du heat to blow over the surface of the wet plastic particles can reduce the moisture content of it to below 0.02% before molding. The PA11 dehumidifying dryer is used The air is fully dehumidified and heated in a closed circulation system, and the dry air quickly completely separates the moisture in the plastic particles to achieve the effect of dehumidification and drying. So,
1. Dehumidifying dryer,dehumidifier dryer There is a damaged line;
2. To prevent electric shock, do not run the machine on a wet floor or after the machine is exposed to rain;
3. If the machine is damaged or disassembled, it should not be overhauled and installed by professional maintenance personnel;
4. During the operation of the machine, at least 1m of surrounding space is required. Please protect this device and flammable materials at least 3m away;
5. Avoid vibration and magnetic influence in the work area.
6. When the ambient temperature is lower than 15℃, the water droplets attached to the surface of the evaporator will freeze to weaken the effect of the dehumidifier. If the ambient temperature exceeds 40℃, the pressure in the system will increase and the compressor will be overloaded. The protector should cut off the circuit, otherwise the compressor motor will be damaged. So the best temperature range of dehumidifier is 15℃～40℃. If the humidity in the air is below 30%, it will be too dry and uncomfortable, so a reliable humidity controller will control it to maintain the range of 50% to 60%. When using, close the doors and windows as much as possible, so that the indoor dehumidification effect is good. The body of the desiccant dryer must be placed flat, not tilted or turned sideways, to avoid machine failure or abnormal noise.
7. The water storage in the Dehumidifying dryer is too full. In order to avoid overflowing and contaminating the ground, when the machine body must be moved during operation, please unplug the power cord first, and then pour out the water in the water storage bucket. Clean the air filter regularly (about once every two weeks) to maintain the dehumidification and dust removal efficiency and life of the machine. Clean the air filter and wash it with water below 40℃; it is better to clean it with detergent. After washing off the dust, rinse it with water, dry it and put it back into the body.
8. When cleaning the body, wipe it lightly with a damp cloth; avoid directly splashing water for cleaning, so as not to damage the electrical insulation. Adhesives on the surface of the body can be cleaned with soap and water. Avoid spraying with gasoline, petroleum spirit, solvents or spray insecticides to avoid peeling paint or discoloration. Do not use thin rods or iron wires to dig out the inside of the machine to avoid malfunction or danger. Please unplug the power cord to maintain the life of the machine when it is out of power, not used for a long time, or when traveling!
Precautions when using dehumidifying dryer:1. The humidifier should be cleaned once a week. Do not put the machine in the water during cleaning. The cleaning water temperature should not exceed 50℃;
2. Do not use detergent, kerosene, alcohol, etc. to clean the body and parts; do not disassemble the parts yourself; clean the transducer with a soft brush; wipe the sink with a soft cloth, once every two weeks; wipe the sensor with a soft cloth; the water tank can be cleaned After filling with water, shake it two or three times and pour it out;
3. If the water quality is hard, it is recommended to equip the humidifier with a tap water filter, try to soften the water before filling the humidifier;
4. The humidifier should be rotated on a stable surface with a height of 0.5m-1.5m, away from heat sources, corrosives and furniture, etc., and avoid direct sunlight; use when the relative humidity is less than 80%, adjust the constant humidity button to block RH> 40%-75%.
Do not touch the surface of the water with your hands, and do not use it in an empty box. Drain the water in the water tank when moving. Do not put it upside down; the water used must be below 40°C, and other types of chemicals are not allowed;
5. According to your own requirements for humidity, reasonably adjust the spray volume and constant humidity value, do not use it under freezing conditions, and stop immediately when encountering a failure.
First, please carry out electrical construction in accordance with the "Electrical Equipment Standards", "Inside Wiring Regulations" and this operating manual.
Second, please do not use power sources other than those specified.
Third, please complete the specified grounding works. (Yellow power cord)
Fourth, please fasten the connectors and connection terminals of the machine body and measuring instrument wires.
Fifth, the power supply must be cut off before the line inspection, and the voltage must be measured with a multimeter after 10 minutes to ensure safety before proceeding with the inspection.
Sixth, do not open the control box door at will during the power-on process.
Seventh, do not touch the machine body, control unit, and other accessories with wet hands.
Eighth, please do not damage the wires, do not put pressure on the wires, do not place heavy objects on the wires, and do not clamp the wires. It may cause electric shock.
Ninth, please professional and technical personnel for wiring and inspection.
Tenth, when you need to disassemble the machine for inspection and cleaning, please cut off the power and compressed air source first.
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