If the ULPA pressure difference remains unchanged, is it clogged or a sensor failure? Drift and Instrument Verification

If the pressure difference of the ULPA filter remains unchanged for a long time, it may be due to low load, small change in air volume, or a problem with the pressure pipe or sensor. It cannot be determined that the filter element is not clogged simply by relying on a straight curve. The flatness of the differential pressure curve has two meanings: one is that there is indeed no obvious dust accumulation on the filter element, and the other is that the data link has been 'stuck' somewhere - the pressure pipe is blocked, the sensor has drifted, or the communication has not been refreshed. The treatment directions for the two situations are opposite. The former does not need to be taken care of, while the latter needs to repair the instrument. Aili Industry isFFU fan filter unit andIn the control scheme of the fan filter unit at the EFU equipment end , the pressure difference, air volume and speed are three independent signals, and the supportingThe FFU computer group control system can compare the changing relationship of the three signals. When the pressure difference remains unchanged but the air volume or speed is changing, the system will give a prompt to distinguish instrument problems from filter element problems.

1. Check the actual operating status: first confirm that the equipment is running and the air volume has changed.

Check whether the fan is running, whether the air volume and speed change, and compare the pre-filtration and production load. Standby readings are not a substitute for operating status trends.

The first direction to check if the pressure difference remains unchanged is whether the equipment itself is running stably. If the fan is stopped or running at low speed, the differential pressure reading will not change significantly. Aili Industry isThe FFU computer group control system records the operating status, air volume, speed and pressure difference synchronously. It can be directly compared during troubleshooting: only when the equipment is running, the air volume changes, but the pressure difference remains unchanged, then you need to check in the direction of the instrument. The relationship between levels and filtering requirements can be found inISO cleanliness level comparison。

2. Check the pressure measurement and instruments: look at the pipeline, zero point and range one by one.

Confirm that the pipelines are not falling off, bent, blocked or incorrectly connected, and check the zero point, range and acquisition settings according to the procedures to avoid data being replaced by fixed values.

If the pressure tube falls off, the reading will change to ambient pressure; if it is bent or blocked, the reading will respond slowly; if the zero point drifts, the entire curve will shift; and if the acquisition settings are incorrect, the data may always display the same value. Aili Industry isHEPA/ULPA filter .The position of the pressure point is marked on the supporting box structure of the The FFU computer group control system supports zero point verification and range setting recording during parameter configuration. Instrument changes can be marked on the trend to avoid misreading of historical data. Please refer to the inspection points for the pressure piping inside the equipment.EFU FAQ and technical support。

3. Cross-check with independent measurements: pair field instrument and system readings

Use appropriate instruments to confirm under comparable working conditions, and then evaluate the filter element after eliminating sensor drift. If a fault is found, it should be repaired and historical data limitations should be noted.

When the values ​​in the operation interface remain unchanged but the field instruments have changed, communication, refresh and data mapping should be checked instead of just replacing the filter element. Aili Industry isFFU fan filter unit andThe control scheme of the fan filter unit on the EFU equipment side supports comparison between local readings and system readings.The data refresh status of the FFU computer group control system can be checked, making it easy to determine whether it is a problem with the sensor itself or a problem with the collection process. For cross-checking methods, please refer toFFU FAQ and technical support。

4. If the pressure difference is zero, it does not necessarily mean that the filter element is broken.

A zero pressure difference does not necessarily mean that the filter element is damaged. Shutdown, pipeline detachment, sensor failure and collection abnormality may cause the reading to be zero, and should be verified one by one.

A broken filter element does cause a drop in differential pressure, but a more common cause of a sudden zero reading is a disruption in the signal link. Aili Industry isWhen the ULPA ultra-high-efficiency filter is delivered, the normal pressure difference range of the model can be explained. When the reading is abnormal, the project party will first check the range to determine whether it is within a reasonable range, and then decide whether to check the meter or the filter element. To judge sealing and integrity, please refer toHEPA FAQs and Selection Guide。

5. Related questions and answers

If the pressure difference is zero, it must mean that the filter element is broken?
Not necessarily. Shutdown, pipeline and sensor failure, etc. may cause this phenomenon, and each item should be checked.

Does a flat pressure differential curve mean there is no problem with the filter element?
cannot. It is also necessary to confirm that the equipment is running, the air volume has changed, and the instruments are working properly before the data can be of reference significance.

How to distinguish sensor drift and filter dust accumulation?
Cross-check with independent measurements under comparable operating conditions. When the sensor drifts, the system readings are inconsistent with the field instrument, and when the filter element accumulates dust, the two change simultaneously.

6. Related articles

ULPA ultra-high efficiency filter FAQ and selection guide

FFU computer group control system

FFU FAQ and technical support

HEPA FAQs and Selection Guide

7. Key points for selection and acceptance inspection

8. Product matching and technical support from Aili Industrial

Aili Industry isFFU fan filter unit andIn the control scheme of the fan filter unit at the EFU equipment end , the pressure difference, air volume and rotation speed are collected as independent signals, and the supportingThe FFU computer group control system can compare the changing relationship of the three signals, and give prompts when the pressure difference remains unchanged but the air volume or speed changes; the system supports comparison of local readings and system readings, data refresh status query and sensor change annotation.The structure of the supporting box of the HEPA/ULPA filter indicates the location of the pressure point.The delivery of ULPA ultra-high efficiency filter can be accompanied by an explanation of the normal pressure difference range. Provide process objectives, installation drawings, operating conditions and acceptance requirements, and can further communicate ULPA standard specifications, non-standard interfaces, samples and batch matching. The specific parameters and test range are based on the confirmed model and technical documents.