Bag filter is a relatively common industrial filter device, which consists of a filter housing and a filter bag. From the number of filter bags installed, there are many bags and single bags; from the filter structure, there are door filters and quick-open filters. Facing so many filter manufacturers and models, how to select the right filter is a difficult problem for industrial users.
In fact, the early form of filtration was simply to tie the filter cloth to the liquid outlet. With the standardization and large-scale production of industrial production, safety requirements are getting higher and higher, and the simple leakage filtration mode does not meet the demand for industrialized large-scale production. Therefore, today’s bag filters are gradually formed. Because the filter bags need to be replaced regularly, the filters are opened very often. Conventional bag filters have not been considered for ease of operation and safety. It uses a plurality of bolts to tightly seal, and when the filter bag needs to be replaced, the process of opening the filter cap is very time-consuming and laborious. After opening the filter cover, on-site workers often need to stand on a high ladder and remove the blocked filter bags. However, the disk has a certain distance from the open face of the filter, and the operation process often requires a tool to remove the filter bag, which is very inconvenient.
The second-generation filter, also referred to as a door-to-filter construction, employs a design where the filter inlet is lower than the faceplate. After the liquid passes through the elbow, it enters the filter bag from the upper part. The advantage of this design is that the upper and lower height of the device is in line with the height of an adult and the faceplate is at the opening. When the filter bag is replaced, the tool bag can be easily removed or installed without using any tools. Moreover, its opening methods have also been reformed, from the traditional left and right translation to upper and lower opening and closing, reducing the space occupied by equipment. As the filter cover is too heavy, the booster device is often installed. Feichao’s patented self-balancing device allows the lid to reach a gravity balance at any angle. A single person can easily open the filter. The door is sealed tightly with the ring bolt instead of the filter, and the opening is quite tedious. The
Filter bag styles that match the filter are more complex and changeable. In order to meet the chemical and physical properties of materials, filter bags can use a variety of materials, commonly used materials are polypropylene, polyester, nylon and so on. The size of the filter bag is mainly designed to match the design flow rate. The main specifications are No. 1 and No. 2 bags, and the No. 2 bag is taken as an example. The usual recommended flow rate is 20-30 m 3 /h. Of course, the flow rate has a certain relationship with the viscosity and the impurity content of the fluid. If the flow rate is large, a multi-bag filter design is needed. At present, the domestic filter bags are relatively similar in size and have a high degree of matching with the filter, and each manufacturer can replace each other. Most filter bags have a maximum filtration accuracy of about 1um and the filtration efficiency is not high. High-precision or absolute-precision filter bags are designed with multi-layer melt blown filter media to achieve deep filtration and improve filtration efficiency.
The service life of the filter bag is often proportional to the filter area. When the filter area increases, the service life will increase exponentially. How to increase the filter area of the filter bag is an important research direction. The Rocket filter bag combines the structural advantages of the filter element and the filter bag. The sealed design of the filter bag allows direct replacement of the existing filter bag without modifying the bag filter. After the folding design, the Rocket filter bag filter area is more than 4 times that of the ordinary filter bag, and the amount of absorbed dirt and the service life are generally higher than the original ordinary filter bag. The increase in the filter area of the individual elements allows the use of only a small amount of Rocket filter bags to achieve the original process requirements when filtering large flows of liquids. At the same time, the number of cover openings is also significantly less, which improves the operator’s work intensity and working environment.
The development of bag filters has been very mature industrial equipment so far, but the industry is still innovating constantly, trying to humane operation, optimizing filtration performance. Selecting a suitable bag filter can help users reduce maintenance costs and reduce downtime.