How to set the upper limit of fan speed after chemical filtration transformation?

The upper limit of fan speed after chemical filtration modification should be set based on the allowable range of the fan, motor and control, as well as the target air volume, noise and system status. In order to compensate for the new resistance, the speed cannot be increased without limit. The new filter section has changed the system resistance curve, the operating point at the original speed has shifted, and the upper speed limit needs to be rechecked instead of using the old value.

1. Check from the actual operating point

Corresponding performance curves and measurement data need to be used to determine the maximum available capacity and commonly used settings. The power changes of different fan types cannot be simply applied.

The new filter section resistance added by the chemical filtration transformation will cause the fan's working point to move in the direction of smaller air volume at the same speed. If you simply increase the upper speed limit to compensate, the rated current of the motor or the maximum allowable speed of the fan may be exceeded. When checking, the fan performance curve and the modified system resistance curve should be used to find the rotation speed corresponding to the target air volume, and then confirm whether the rotation speed is within the allowable range. Aili Industry ischemical filter modification plan, check the fan working point according to the new resistance.In the When the FFU chemical filter is used with an EC fan, the available speed can be confirmed according to the speed adjustment range. Industry data also points out that if the fan selection is designed based on the maximum pressure drop, the actual operating point rarely occurs, which may not be economical in terms of energy consumption, fan size and cost. The relationship between levels and filtering requirements can be found inISO cleanliness level comparison。-9

2. Check filtration and airflow at the same time

Increasing the rotational speed may change the actual flux and distribution of the filter section. After setting, the wind speed, pressure difference and target gas should be verified, and the necessary operating margin should be retained.

The upper speed limit is not just an electrical parameter, it directly affects the filter section flux and airflow organization. After the rotation speed is increased, the wind speed on the filter section surface increases, the contact time of the chemical medium may be shortened, and the gas treatment effect needs to be re-confirmed. At the same time, changes in wind speed will also affect the resistance and efficiency of the particle filter section. Aili Industry isIn the box-type chemical filter package, check the filter section flux according to the target air volume.The resistance data of V-type chemical filters are provided based on actual operating conditions. The relationship between speed adjustment and filtering effect can be referred toHEPA FAQs and Selection Guide . The EC fan speed range of the chemical filter FFU needs to be confirmed before modification, and it cannot be assumed that it can be increased infinitely.

3. Examples of project judgment

When the highest level still cannot meet the air supply requirements, you can expand the area, optimize the air path, or change the type instead of continuing to increase the control command.

If the speed has reached the allowable upper limit and the air volume is still insufficient, continuing to increase the command may trigger protection or damage the motor. At this time, other options should be evaluated: expanding the filter area to reduce resistance, optimizing the air path to reduce elbow losses, or replacing a fan with a larger capacity.

4. Application Check Points

5. Verification and subsequent use

Cost comparison requires uniform service levels. First maintain gas control, necessary ventilation and representative operating conditions, and then compare investment, power, maintenance and replacement. For parameters that have not yet been verified, the estimation conditions should be retained and gradually revised through operating data to avoid taking short-term results as long-term conclusions.

Aili Industry ischemical filter modification plan, the operating limits are set according to the allowable range of the fan and the resistance of the filter section.In the Plate chemical filters allow evaluation of alternative configurations when space is limited. After setting the upper speed limit, it should be recorded in the operating file to avoid arbitrary adjustments later.

6. Related questions and answers

Can the speed be directly adjusted to the highest speed after modification?
Not recommended. It is necessary to check the allowable range of the fan and motor, and whether the filter section flux and air flow organization still meet the requirements.

Is the upper speed limit considering only the motor power enough?
not enough. Also consider the maximum allowable fan speed, noise, filter section surface wind speed and gas contact time.

What should I do if the air volume is still insufficient when the speed reaches the upper limit?
You should evaluate expanding the filtration area, optimizing the air path, or replacing the fan instead of continuing to increase the control instructions.

7. Related articles

Chemical filter product series

FFU chemical filter

Box chemical filter

HEPA FAQs and Selection Guide

What is a chemical filter FFU? The main difference from ordinary FFU?

8. Key points for selection and acceptance inspection

9. Aili Industrial products and equipment supporting equipment

Aili Industry provides chemical filters and clean air supply equipment selection packages. It can compare FFU package, box type, flat type and V-shaped products according to gas composition, treatment air volume and installation conditions. The manufacturing and supporting system covers the independent research and development and production of motors and fans, control systems, sheet metal, air filters and complete machine assembly, making it easy to jointly confirm the filter section, power and structural conditions. The specific gas effect, environmental suitability and service life still need to be verified based on the corresponding configuration data and actual working conditions.

learnChemical filter product series , check the products and air supply matching according to the project conditions. Clarify the goal → Check the conditions → Verify the effect → Arrange maintenance.