How to maintain ULPA pre-filter? Inspection cycle and blockage treatment

ULPA filter pre-filtration maintenance should be combined with upstream pollution, pressure difference, appearance and system air volume arrangements. Blockage of the pre-filter will increase resistance, and damage or bypass may cause the final filter element to bear more pollution load. Whether the pre-filtration maintenance is done well will directly affect the frequency of replacement of the terminal ULPA - when the front stage fails, the terminal filter element will accumulate dust in a shorter period of time, and the replacement cost will increase accordingly. Aili Industrial's product lines range from primary effect, medium effect toChemical filters are all covered, and pre-filtration solutions can be matched according to the grade requirements of the terminal ULPA and the upstream pollution characteristics, so that the pre-filtration can truly play a protective role, rather than just a formality.

1. Confirm the pre-filtering structure and boundaries: first figure out how many levels there are and what each controls.

Record the grade, location, size and sealing method, and clarify whether there are multi-stage filtration and independent pressure tapping points at each level.

There may be more than one level of pre-filtration, and different levels have different filter objects and replacement cycles. Aili Industry isThe HEPA/ULPA filter matching solution can be configured with a combination of primary efficiency and medium efficiency according to the upstream pollution characteristics.Chemical filters are set separately for gaseous pollutants. If there are independent pressure points at each level, the pressure difference data can reflect the resistance of each section separately, making it easier to determine which level needs to be processed. The relationship between levels and filtering requirements can be found inISO cleanliness level comparison。

2. Inspection and treatment should be carried out by classification: dust, damage, moisture and looseness should be judged separately.

Dust accumulation, damage, moisture and loose installation should be judged separately. Whether it can be washed is determined by the pre-filter product instructions. All filter materials cannot be regarded as washable.

Dust accumulation can be judged by pressure difference and visual inspection, and the treatment method depends on whether the pre-filtration of this level allows cleaning; damage will form a bypass, and visual inspection can reveal that the filter material is cracked or the frame is detached; the resistance characteristics and structural strength of the filter material may change after being damp; loose installation will allow air to bypass the filter material. Aili Industry explains the cleaning and replacement conditions according to the model when matching pre-filter products.Products such as box-type chemical filters have corresponding maintenance requirements, and the project can be carried out according to the product instructions instead of 'washing as long as it can be washed'. For the cooperation between pre-filtration and terminal filter element, please refer toHEPA FAQs and Selection Guide。

3. Check the status of the whole machine after maintenance: the air volume may change after replacing the pre-filter

The air volume may change after replacing the pre-filter. It is necessary to check the control settings, pressure difference and terminal operating conditions, and update the ledger at the same time.

The initial resistance of the new pre-filter is low. After replacing it, the total resistance of the system will decrease and the air volume may increase. If the fan is running at a constant speed, the increase in air volume will increase the wind speed on the end ULPA surface and increase the resistance faster. Aili Industry isFFU fan filter unit andThe control scheme of the fan filter unit on the EFU equipment side supports speed adjustment. After the pre-filter is replaced, the air volume setting can be re-checked. The supportingThe FFU computer group control system can record operating parameters before and after maintenance, making it easy to confirm whether the air volume has returned to the design range.

4. If the front-stage pressure difference suddenly drops, check for damage or bypass instead of treating it as an improvement.

If the pressure difference of the front stage suddenly drops but the dust accumulation at the end accelerates, you should check the front stage for damage or seal bypass, rather than just treating the drop as an improvement. The drop in pressure difference may be caused by rupture of the filter material, detachment of the frame, or loose installation, causing the air to bypass. At this time, the front stage seems to have 'less resistance', but it actually loses its filtering effect.

In the sealing structure design of pre-filtration products, Aili Industry will clarify the cooperation requirements between the frame and the installation frame.Disposable structures such as disposable high-efficiency air supply vents also have corresponding installation specifications. For troubleshooting ideas for abnormal front-stage pressure differences, please refer toULPA ultra-high efficiency filter FAQ and selection guide。

5. Related questions and answers

Is the more efficient the preamp the better?
It is necessary to balance the protection effect and system resistance, and confirm that the fan has the ability to maintain the target air volume. If the resistance of the front stage is too high, the total resistance of the system will increase.

Can all pre-filters be cleaned?
cannot. Whether it can be cleaned is determined by the pre-filter product instructions, and different filter materials are treated differently.

Is it a good thing that the front stage pressure drop suddenly drops?
uncertain. It may be that the filter material is damaged or the seal is bypassed. The status of the front stage should be checked instead of directly regarded as an improvement.

6. Related articles

HEPA FAQs and Selection Guide

chemical filter

Box chemical filter

ULPA ultra-high efficiency filter FAQ and selection guide

7. Key points for selection and acceptance inspection

8. Product matching and technical support from Aili Industrial

Aili Industrial's product lines cover primary-effect, medium-effect tochemical filters , available by endPre-filter configuration for HEPA/ULPA filter grade requirements and supporting solutions for upstream pollution characteristics; pre-filter products describe cleaning and replacement conditions according to model.Box chemical filter、Structures such as disposable high-efficiency air supply vents have corresponding installation specifications.FFU fan filter unit andThe fan filter unit on the EFU equipment side supports speed adjustment, and the air volume setting can be rechecked after the pre-filter is replaced.The FFU computer group control system records parameters before and after maintenance. Provide process objectives, installation drawings, operating conditions and acceptance requirements for further communicationULPA ultra-high efficiency filters . Standard specifications, non-standard interfaces, samples and batch matching of The specific parameters and test range are based on the confirmed model and technical documents.