Views: 0 Author: Site Editor Publish Time: 2022-11-18 Origin: Site
Let's look at a case first:
This customer use filter media with a filter efficiency of over 99.5%, make them into filter elements, and send them to us for testing.
The size of these filter elements are small, so SC-MBT-2032 portable filtration tester is selected as the test equipment.
Test results are as follows:
As shown in the figure, the filtration efficiency of the filter elements are less than 90%.
The result was fed back to the customer, and the customer felt incredible, because in his mind: "I used a filter media with a filtration efficiency of over 99.5%, so the efficiency of the filter element must be over 90% or even over 95%".
The test equipment doesn't lie, that's the test results, subverting cognition. The filtration efficiency of the media cannot represent the filtration efficiency of the filter elements.
In particularly, many manufacturers of filter elements does not have their own testing equipments, neither filter media tester nor filter elements test system. The efficiency of the filter media depend on the datas provided by the supplier, and believe that the efficiency of filter elements are the same as the filter medium. What about the facts? Isn't that so?
1. Regarding filter medium, whether the data provided by suppliers are true and accurate, and whether the uniformity and stability of filter medium are good enough. However, the uniformity and stability of the filter medium are the difficulties in the production of filter medium.
2. Product design and manufacturing process quality control of filter elements.
1) Structure of filter element
When the frame specification of filter element is determined, the structural design is particularly important. The structure of the filter element determines its filter efficiency for particles and harmful gases. How to distribute filter media reasonably in a limited space? How to choose the best folding width, folding number and filtering area need special attention. The larger the filtering area, the higher the dust capacity, the smaller the filtering resistance and the longer service life. The filtration area needs to be calculated according to the rated air volume of the application occasion. After the filter area is determined, parameters such as folding width and folding number are determined.
The seal here includes the seal of the filter element itself and the seal between the filter element and the outer frame.
After the filter element is folded, both ends need to be sealed with glue or foam material.
After the filter element is bonded with the filter frame, it is a finished filter. In the bonding process, rubber sealing strip, latex and adhesive can be used for manual operation, or automatic glue injection can be used. Automatic glue injection is not a one-time molding, and it needs to be filled with glue once, twice, three times, etc.
Traditional filter element production depends on people, and the sealing process needs a lot of manual operations. With the development of technology, more and more automatic glue-filling lines are produced, and the control of the amount and the route of glue are more stable.
In addition to the glue injection method, the type and proportion of sealing glue are also very important, and it also needs a lot of tests to match and screen.
In the process of raw material inspection and filter manufacturing, attention should also be paid to the influence of people and machines, so as to avoid filter damage as much as possible, otherwise the filter performance will be affected. This is more important in HEPA and ULPA filters. These two groups of filters are used in places with high cleanliness requirements, and the filters of these two groups need to be leak-tested one by one.
Filter industry is a highly specialized industry, but there are few corresponding courses in universities. It can be said that it is an industry that needs practices and experiences. From filter media to filter elements, there are many factors that affect the filtration efficiency of finished filter elements. Material selection and structural design of filter element stage are need testing equipment. The detection of finished filter elements is also essential. No matter how good the filter medium are, it is inevitable that the filter material will be damaged and the bonding will be incomplete in the process of discount and adhesive bonding.
Filters for different occasions, such as vacuum cleaner, air purifier, automobile air conditioner, HVAC system, clean room, etc. Flat, V-bank, filter bag, cylinder and other filter elements with different shapes; F-group, HEPA-group, ULPA-group and other filters of different grades. For these filter elements with different uses, shapes and grades, Scince Purge has corresponding testing equipment.