The suction gas dryer requires periodic regeneration, which usually uses approximately 15% compressed air for purging. When the vacuum pump is used, the blowing capacity of compressed air can be reduced from 15% to 5%, so as to produce 10% more surplus compressed air. All industries that need a lot of compressed air can be used, such as pulp mills, steel mills, chemical plants and glass production. This is the application of rotary vane vacuum pump in compressed air.
How is compressed air produced?
Compressed air is the air that is compressed by mechanical movement of air compressor to reduce volume and increase pressure. Compressed air is an important power source, with the advantages of no pollution, clear and transparent, convenient transportation, no harmful performance, no fire hazard, etc. Therefore, it is widely used in all aspects of the production enterprise, such as the operation of processing machinery, transmission and control of pneumatic valves, cylinders and controllers, transmission medium or purge gas, etc. In order to obtain dry, dust-free, oil-free and clean compressed air, it must be purified. The filter system can remove oil, dust and desiccator to dehydrate water. All of these need to be used in rotary vane vacuum pump.
Because the impurities such as solid, liquid and gas contained in compressed air have their own characteristics, it is impossible to achieve the purpose with a single equipment, so how can compressed air be dried and purified?
Method of compressed air drying:
1. Adsorption drying method
The adsorption drying method is to use the adsorption capacity of adsorbent for water, such as silica gel, activated alumina and molecular sieve, which have strong adsorption capacity for water. The adsorption process of adsorbent is a physical change, so this kind of adsorption is characterized by regeneration, adsorption under high pressure, desorption under low pressure, namely pressure swing adsorption (PSA); adsorption under normal pressure, regeneration during heating, namely temperature swing adsorption (TSA); or adsorption under high pressure and normal temperature, desorption under normal pressure and high temperature, namely temperature swing adsorption (PTC). The dryness of this kind of adsorption drying can reach the atmospheric dew point – 70 ℃.
2. Freeze drying
The freeze-drying method is to cool the compressed air by using the cooling capacity generated by the rotary vacuum pump drying, so that the compressed air can reach the dew point temperature corresponding to its pressure, so that the water in the compressed air can be analyzed, so as to achieve the purpose of drying. The dryness of this kind of drying method can reach the atmospheric dew point – 23 ℃.
3. Deliquescence drying method
The deliquescence dryer also uses the adsorption characteristics of the adsorbent for water, but the deliquescence type adsorbent becomes liquid after absorbing water, and the deliquescence type adsorbent can not be regenerated, and will cause pollution to the environment. This method is also called chemical method. This kind of drying device can reach the dew point of – 38 ℃.
Rotary vane vacuum pump in compressed air working principle:
1. Carry the compressed air containing dust, oil, rust, water and other harmful substances into the first stage filtering device of the compressed air filter.
2. When the compressed air passes through the first stage tubular mesh filter element, it will produce coalescence effect, the larger particles will be adsorbed on the filter material, and the water will condense into larger water droplets.
3. When entering the separation chamber, the speed of compressed air slows down, so that the particles gather again, and the water mist condenses on a honeycomb water collector again.
4. The water carrying the impurity particles flows to the drainage device along the bottom and is discharged through the automatic or electric drain valve.
5. More than 95% of the water drops, oil and large particles in the compressed air have been filtered by the first filter element, and the compressed air after the first filter enters the second filter element.
6. When the compressed air passes through the fiber filter screen made of special cotton in the second stage, thousands of small vortices will be generated. At the same time, the compressed air will be accelerated dozens of times. The center of the vortices is like a tornado, forming a vacuum state. The water drops that are not filtered in the first stage are gasified, transformed and filtered again. At the same time, particles as small as 5 microns are also completely filtered in the second stage Eliminate.
7. Through two-stage filtration, the clean and dry compressed air without dust, rust, oil and water drops can be achieved to ensure the normal operation of pneumatic equipment and extend the service life of pneumatic equipment.