What’s a mini pleat HEPA filter?
The mini pleat HEPA filter is an air filter named according to its media processing structure.
It adopts hot melt adhesive as the separator of the filter element instead of aluminum separators, which is convenient for mechanized production.
In production and life, many HEPA filters are made of mini pleat structures, also called mini pleat HEPA filters.
Brief of mini pleat HEPA filter
Coupled with its advantages of small size, lightweight, easy installation, stable efficiency, lower pressure drop, and uniform air velocity, the filters required for large quantities in clean plants mainly adopt the structure of a mini pleat.
In addition, compared with the rectangular channel of the deep pleat HEPA filter, the V-shaped channel of the partitionless filter further improves the uniformity of dust capacity and prolongs its service life.
Mini pleat filters for ventilation can avoid the use of metal parts and are easy to dispose of when disposed of, meeting the increasingly stringent environmental requirements.
Except for some special applications requiring high-temperature resistance and high safety, Mini pleat hepa filters can replace deep pleat HEPA filters.
There are many kinds of HEPA filters, and different HEPA filters have various usage effects.
Among them, the mini pleat HEPA filter is standard filtration equipment, generally used as the end of the filtration equipment system for efficient and precise filtration.
Mini pleat filter without melt glue thread
Some mini pleat filters do not even have a separator, and the filter paper is directly made into a corrugated shape with grooves, or the filter paper is “bubbled.” These filters do not have a separator.
Usually, we call them mini pleat filters without separators or melt glue thread.
Mini pleat filters can now replace deep pleat filters
Minimal pleat filters take up less space than traditional deep pleat filters. The production cost is low, and the quality of products can be easily controlled.
Mini pleat filters have replaced most traditional deep pleat filters, especially high-performance filters for cleanrooms, and are gaining more and more market share in general ventilation filters.
Product features of mini pleat hepa filter
- Dense pleated “V” structure, sizeable effective filtration area in same dimensions, small size.
- Low resistance, good durability, and even airflow.
- A more petite, lighter frame can be used to reduce weight for easy handling and installation.
- The thin, lightweight product design allows for flexible installation, replacement, and upgrade.
- The product’s performance is better than two times the height of a deep pleat filter.
History of mini pleat filter
In 1936, Rabofsky of Berlin invented the pleating machine that used a cam mechanism to drive two upper and lower blades to fold fabric or paper into a fan-like pleated structure for women’s pleated skirts and packaging materials.
Mr. Rabofsky registered his own company and sold his technology to an Italian and a French company, later using the folding paper machine to produce air filters. That French company became the originator of the mini pleat filter.
The French company bought a folding paper machine in 1960 to pleat the filter media for gas masks. Later, the French company was merged with another filter company.
In 1971, the filter company linked two pleating machines together, with the front one pleating the filter paper and the back one inserting strips of paper between the filter papers, which was the original mini pleat filter line.
In 1975, the filter company replaced the paper strips with glued threads and the paper pleating machine with a fluting roller pleating machine.
In the early 1990s, mini pleat technology was demystified.
Later, American companies introduced mini pleat filters with hot melt adhesive instead of filament, an improvement that simplified equipment and reduced production costs.
In the 1990s, the production of mini pleat filters blossomed everywhere.
Currently, filters using roll-pleating equipment and hot melt adhesive as separators are the most common mini pleat filters.
Current Status of mini pleat filter production
Today, the production technology of mini pleat filters has been dramatically improved.
Some small private companies can make good mini pleat filter production equipment, both traditional paper pleating machines and roll pleating machines, and the price is relatively moderate.
Applications of mini pleat hepa filter
Most pharmaceutical companies, chip factories, and hospitals prefer mini pleat hepa filters. The filtration efficiency ranges from H13 to U16.
In civil use, due to the excellent processing performance, small size, and good filtration effect, the mini pleat hepa filters are designed in various shapes and used in many air purifiers, vacuum cleaners, dehumidifiers, and other household appliances.
It is suitable for reducing contamination in the air, improving indoor air quality, and guarding people’s health.
The filter material of the mini pleat hepa filter
Glass fiber and synthetic fiber
As air filter media, glass fiber, and synthetic fiber had three battles for HEPA filters, synthetic fiber challenged glass fiber.
For bag filters, glass fiber dominated for a long time. There was not much synthetic fiber then, and the air filters could not afford to use it even if there was.
Synthetic fiber has the characteristic that the material can carry static electricity, and the resistance of the filter is not changed, but the efficiency is improved.
The first war between Glass fiber and synthetic fiber
In the late 1980s, chemical fiber was not so honored. It hurried to the battle to the glass fiber. Glass fiber indifferently to do some experiments, proving that the filter efficiency with electrostatic filter media can not rely on.
At that time, the polyester type chemical fiber was used because the material was hydrophilic, and its electrostatic force was unstable.
Glass fiber took little effort then chemical fiber was defeated.
The second war between Glass fiber and synthetic fiber
In the mid-1990s, chemical fiber filter media made significant progress, and the static electricity on the filter media was stabilized thanks to hydrophobic materials and the correct “electret” technology.
At this time, chemical fiber rechallenged glass fiber with rising a sign of environmental protection.
(chemical fiber is incinerable, with low energy consumption in the production process).
It threatened to scrap glass fiber in a few years.
Glass fiber still responded with “service life,” claiming that, according to the filtration principle, chemical fiber is coarse and soft, and its service life and dust capacity cannot reach the level of glass fiber.
This time, both sides fought a draw in the market.
The third war between Glass fiber and synthetic fiber
In the late 1990s, chemical fibers declared war for the third time. This time, the electret technology was more perfected, and the dust capacity of chemical fiber filter media was greatly improved.
But this time, chemical fiber avoided the topic of performance and put away the environmental sign. Chemical fiber is playing the price war.
This time, chemical fiber won.
Air filters have been used as industrial products for nearly a century.
Almost every fiber material that could be found has been tried and tested for a long time.
And after numerous screenings, the dominance of glass fiber has been established.
However, with the continuous advancement of chemical fibers and the current obvious price advantage, the application of glass fiber in pocket filters has significantly been reduced.
Pocket filters now use more chemical fiber materials.
Claims of different scholars
Some scholars who study glass fiber believe that glass fiber does not contain active substances and is the safest material among all inorganic fibers.
The prominent harm of glass fiber is to sting people (when the diameter ≥ 5um). The fiber diameter of glass fiber insulation material is 7~20um, which is not very inviting.
In contrast, the bag filter media fiber is fine, generally between 0.1 – 5um. People do not feel how much it stings.
Scholars who study filtration theory believe that the fibers in the filter material should be as fine as possible for high efficiency: more fibers and low resistance.
But too fine fiber and it is too soft, with the accumulation of dust, and a slight increase in resistance, the fibers can not stand, and the result is accelerating the rate of growth in filter resistance.
Glass fibers can be very fine while maintaining a specific stiffness that is difficult to achieve with chemical fibers.
When the price of chemical fiber filter media makes people less concerned about its longevity, or when the longevity of chemical fiber materials can compete with glass fiber, then it is time for glass fiber to retire.
HEPA filters have always been dominated by glass fiber, but in recent years, some air filter manufacturers have used electrostatically charged PTFE fibers (electret) to manufacture HEPA filters.
This filter material is resistant to hydrogen fluoride and has high strength, but the price is high.
In a few years, glass fiber will give way to other materials in this area of HEPA filters.
The mini pleat HEPA filter in the application of FFU
Due to its thin thickness, the mini pleat hepa filter can be processed in a wide range in the length direction, with a large filtering area, good filtration effect, low resistance, lightweight, and easy installation.
Therefore, all FFUs use mini pleat HEPA filters, and the standard filter efficiency is H13 and H14, sometimes can be U15-U16.
The filter material used is glass fiber.
What is FFU?
The full name of FFU is: Fan Filter Unit, meaning: fan filtration unit, is a self-powered air supply filtration device, a modular end air supply device with filtration effect, is a kind of end air filtration equipment.
Principle of FFU
Air is drawn in by the fan (motor + impeller) inside the FFU.
The absorbed air is filtered by the HEPA (High-Efficiency Filter) or ULPA (Ultra High-Efficiency Filter) filters under the FFU to filter out the particles and dust in the air. Finally, the clean air is sent to the clean area at a consistent speed.
FFU can be modularly connected and used in clean rooms, workstations, production lines, assembled clean rooms, and partial 100-level clean applications.
FFU is equipped with two levels of primary and mini pleat hepa filters.
The fan draws air from the top of the FFU and filters it through primary and HEPA filters, and the filtered clean air is sent out at a uniform speed of 0.45M/S±20% throughout the air outlet.
It is suitable for obtaining a high-level clean environment in various places. It provides high-quality clean air for clean rooms and microenvironments of different sizes and cleanliness levels.
Composition of FFU
- Shell
Shell commonly uses galvanized aluminum-coated steel, aluminum alloy, or stainless steel.
The role of the shell is to support the fan and the air guide ring and support the deflector.
- Flow guide plate
It’s a balancing device for airflow built into the shell’s interior around the bottom of the fan.
- Fan
There are single AC (AC/1Phase), DC (EC/1Phase), and three AC (AC/3Phase).
- Control components
AC FFU commonly uses a five-speed governor or an infinitely variable-speed governor.
The control chip of the DC system is embedded inside the FFU motor, and remote control is realized with the help of special control software, a computer, a control gateway, and a network line.
- Air Filter
FFU has two filters, one is the primary filter, and the other is the mini pleat hepa filter.
The primary filter is installed at the top air inlet of the FFU as the air inlet filter.
The mini pleat hepa filter is installed as the end filter at the bottom outlet of the FFU.
The use of mini pleat hepa filters in household appliances
Hepa filters for household appliances are mainly made of PP, PET, or PET/PP melt-blown composites.
Mini pleat hepa filters in air purifiers
The HEPA filter is the heart of the air purifier, mainly used to filter fine particles above 0.3 microns. It is characterized by a powerful filtering capacity for tiny-diameter dust, a large filtering capacity, and high efficiency in treating air pollutants.
As we all know, the most common PM2.5, PM10, etc., can be filtered through air purifiers to improve indoor air quality.
The air purifier on the haze weather purification effect is through the HEPA filter to achieve.
An air purifier can handle 100% of the secondhand smoke because the cigarette particles are in the range of 0.5 – 2 microns in diameter and cannot pass through the HEPA filter.
Hepa filters for air purifiers are of mini pleat construction due to the flexible mechanical processing properties of mini pleat filters that can be designed and processed into various shapes.
It also maintains the characteristics of small size and high filtration efficiency.
Depending on the shape of the air purifier, the mini pleat Hepa filters are usually made into the panel or cartridge types.
Panel-type HEPA filters are usually made with PET frames.
Cartridge Hepa filters have PET or PP plastic end caps.
Mini pleat hepa filters in vacuum cleaner
To protect the vacuum cleaner motor and to prevent the dust absorbed by the vacuum cleaner from being distributed to the indoor environment, forming secondary pollution, many vacuum cleaners are now equipped with HEPA filters.
Due to the compactness of the vacuum cleaner and small size of the vacuum cleaner, the shape of the HEPA filters of vacuum cleaners is tremendous, and their size is mostly smaller than the air purifier HEPA filters.
Therefore, many vacuum cleaners do not have pleated filters or are not separated by hot melt adhesive after pleating.
However, some are separated by hot melt adhesive and are mini pleat HEPA filters. This hot melt adhesive increases the mini pleat filter’s structural strength to match the more considerable airspeed.
