The filter element is a component in the powder recovery system of the spray room. The quality of the filter element itself will affect the recovery effect of the overall equipment. The quality and configuration of other components in the powder recovery system will also affect the filter efficiency and the product life of the filter element.
The difference between Yongkang Saifu Filter Co., Ltd. and other filter enterprises is: we insist on more than ten years to do only coating powder recovery filter; We know the powder recovery filter element; We know more about how to configure the filter element according to the actual working conditions in the powder spray room, so that the filter element plays a greater role in the powder recovery system.
First, the effect of wind speed on filtration efficiency
Since engaging in the powder recovery filter element, some coating equipment manufacturers often report that there is a relatively obvious powder permeation phenomenon at the exhaust air of the powder spray room shortly after completion, or the powder flies everywhere at the hangings of the spray room; In the working area of spray parts, the plastic powder flapping produced obvious powder overflow phenomenon. When encountering this series of problems, customers often habituated to think that the phenomenon of permeation is due to the filter cloth aperture is too large, and the plastic powder runs out; The phenomenon of powder overflow is due to the small aperture of the filter cloth, and the air permeability can not reach. Although the aperture of the filter cloth will have a part of the impact on the permeable powder overflow, the filter element filtration is definitely not a simple powder screening principle, in the design and production of powder spray room, setting a reasonable wind speed is the key to the operation of the equipment. In the operation of the equipment, if the wind speed of the air through the filter cloth is too large, it will cause the wind pressure difference to increase, then some powder particles with the excessive wind pressure air through the filter cloth, is discharged into the air pipe, resulting in powder. The practical data show that for the powder recovery filter element, the transmission rate of the powder is increased by one order of magnitude when the wind speed is doubled, and the filtration efficiency is reduced by one. When the wind speed is reduced by half, the transmittance of the powder will be reduced by an order of magnitude, and the filtration efficiency will be increased by 9, so a reasonable wind speed setting is a prerequisite for the operation of the equipment. According to the observation and summary of the powder spray room over the years, we suggest that the speed of the air flow through the filter cloth should be set in the range of (1.2m/s~1.5m/s) for the powder spray room discharged indoors. The spray room where the air pipe is connected to the outdoor emission can be slightly larger, because since the equipment manufacturer and the user have chosen the outdoor emission method, it is equivalent to acquiescing that a small part of the powder can run out and be directly discharged.
For the powder room that has been completed, if there is a powder overflow phenomenon, because the fan has been fixed and installed, the number of installation space of the filter element can not be changed, then you can affect the filtration speed by changing the filtration area of a single filter cartridge, so as to improve the filtration efficiency of the filter element. The filter element made of polyester fiber non-woven filter material, such as Saif's 325*215*600, has a filtration area between (4.5m²~10.2m²). Customers can choose their own filter specifications according to the size of the spray room structure and the level of filtration efficiency requirements, and the filter element suitable for you is the best filter element.
Second, the impact of powder cleaning on the filter efficiency and filter life
The same specification parameters, the same filter element of the filter material, in different working environments, the filter efficiency and product life of the filter element are also very different. In the process of using the filter element, whether the accumulation of powder on the surface of the filter cloth can be cleaned promptly and effectively is the key to affecting the filtration efficiency and product life of the filter element. Cleaning the powder on the surface of the filter element, the most commonly used method on the painting equipment is pulse shock type, pulse shock: compressed air is sprayed from the valve instantaneously through the solenoid valve, forming a stream of air acting on the inside of the filter element, to complete the powder cleaning on the surface of the filter element. There are four factors affecting the cleaning effect: 1. Air pressure; 2, gas cleanliness; 3, filter material; 4. Filter element structure.
1, The air pressure is too small is absolutely not clean filter surface accumulation of powder, in the case of filter strength tolerance, the greater the better, the general painting equipment manufacturers are set up about 5kg of air pressure, which mainly takes into account the conventional filter capacity on the market is limited, the company through special materials made of filter can withstand (8~10)kg of air pressure, The filter element structure will not be deformed and the filter cloth will not be torn.
2, Through the compressed air into the solenoid valve gas will also affect the blowback effect, if the gas contains water oil, oil and water will penetrate into the filter material and plastic powder bonded together, then no matter how large the air pressure can not shake the filter cloth surface powder, so the air compressor in the powder spray room must be configured with the corresponding filter for oil and water separation.
3. The quality of the filter material of the powder recovery filter element itself will also affect the powder cleaning effect, compared with the domestic filter material, the imported high-quality filter material is easier to depowder; Compared with the traditional polyester fiber filter cloth, the surface treatment of the filter material powder effect is more obvious, such as the substrate surface is treated with fluorine resin, the filter element has the function of oil, water and pollution prevention; When the surface of the substrate is treated with polytetrafluoroethylene coating, the filter element appears as the surface filter form, the plastic powder will not enter the inside of the filter material, and the powder can fall off the whole piece when the pulse shock.
4, The appearance of the filter element structure can also directly affect the powder cleaning effect. Compared with the traditional cylindrical filter, the shape of the conical filter is large at the top and small at the bottom, and the plastic powder is easier to fall off during pulse shock. The bottom leakage type filter element makes the powder fall directly to the bottom of the powder room, and the small diameter shallow folding distance filter element can make the filter cloth expand outwards when the pulse shock, and shake off the plastic powder on the surface of the filter cloth.
In the process of using the powder spray room, if the plastic powder is not cleaned up, we must analyze and find out the reason, and then solve the problem. Remember not to hit the surface of the filter element directly with a stick, and do not clean the filter element with water, because beating with a stick will cause the surface of the filter cloth to be damaged, and the support network in the filter element will bend and shrink, which will quickly cause the filter element to be scrapped. Water to clean the filter element, we think that this is the practice of masking, water is able to directly clean the plastic powder on the surface of the filter cloth, but the small particles of dust hidden in the filter fiber once it encounters water will be bonded into a paste, adhering to the fibers inside the filter material, which will cause insufficient air flow, increase the resistance of the filter element, and seriously shorten the service life of the filter element. In principle, we do not recommend that customers clean the filter element with water.