Chemical filter selection requires knowledge of daily operating hours, as this, along with air volume and inlet concentration, affects cumulative load and maintenance schedules. Just knowing the hours per day is not enough to give a fixed lifespan. Running time is one item in the selection data, not all of it.

Running time answers the question of cumulative load

The capacity consumption of chemical filter elements is essentially a cumulative process of 'how much gas has been processed.' This cumulative amount is roughly determined by the multiplication of inlet concentration, air volume and operating time. Running 8 hours and 24 hours a day, under other conditions being the same, the annual cumulative load differs several times, and the replacement cycle and maintenance schedule are naturally different. Therefore, the running time is not a dispensable background information. It directly affects how long the filter element can last and how to prepare spare parts. But it is only one of three variables and cannot be used alone to predict lifespan.

System running time and pollution occurrence time are not the same thing

If the fan is on, it does not mean that pollution is still being generated; if the fan is stopped, it does not mean that the medium is no longer in contact with the polluted air. Common situations in clean rooms are: there is cleaning and process release during the production period, and the fan continues to operate at pressure after production is stopped. The pollution load has dropped but the system is still running; or the fan stops at night and the filter section is open in the box and is still in contact with the surrounding air. In these two cases, using 'system operating hours' to directly calculate the filter element life will result in a large deviation. A more reasonable approach is to separately record the concentration changes during the system operation period and the pollution occurrence period. For questions about whether the filter element still consumes capacity during shutdown, please refer toWill gas handling capacity still be consumed after a chemical filter is shut down?。

Shift changes can alter maintenance baselines

Changing a single shift to two shifts, changing two shifts to continuous operation, or changing weekend shutdowns to continuous pressure maintenance will change the cumulative load and maintenance rhythm. This type of change is easily overlooked in the early stages of the project, because the filter element model has not changed and the air volume has not changed, but the operating time has changed. If the maintenance plan is still based on the old shift, there may be premature penetration of the filter element or excessive replacement. The running time data should be recorded together with the shift schedule and production status, and the maintenance baseline should be rechecked after the shift is adjusted. For issues involving intermittent operation replacement cycles, please refer toHow to calculate the replacement period for a chemical filter that operates intermittently? Is downtime included?。

How to fill in the running time in the selection list

The running time needs to be filled in together with the air volume, concentration, temperature and humidity. A single item is meaningless. A more practical recording method is: hours per day during normal production periods, hours per day during cleaning or peak hours, hours per day during shutdown and pressure maintaining periods, and the inlet concentration or odor performance in each period is recorded separately. What you get in this way is not a big number, but a load table divided into time periods, which will provide more basis for subsequent capacity estimation and maintenance arrangements. If there is no concentration data by time period, at least the system operating time and production time should be recorded separately.

Aili industrial supporting equipment

We usually look at data such as operating hours together with air volume, inlet composition and shift schedule when matching, instead of just asking how many hours it is operated every day. Aili Industry can provide selection packages for box-type, flat-plate and V-type chemical filtration products. For box-type MAU packages, please refer toMAU box type chemical filter , product series can be viewedChemical filter product range . The V-shaped structure provides a larger filtration area in the same box space, which helps control surface speed and resistance increase during long-term operation. Equipment-side applications can adopt the form of chemical filtration FFU, integrating chemical adsorption layer and HEPA/ULPA particle filtration. The manufacturing end covers motors, fans, control systems, sheet metal and complete machine assembly. Air volume and resistance adjustments caused by changes in operating shifts can be checked together during the matching stage. The specific gas effect, applicable environment and replacement cycle still need to be verified based on the corresponding configuration data and on-site working conditions. The actual results are subject to on-site leak detection and gas detection results.

Related questions and answers

What is the difference in filter life between running 8 hours and 24 hours a day?
It cannot be calculated only on an hourly basis. It also depends on the inlet concentration and pollution occurrence in each period. The pressure holding period with low concentration and the production period with high concentration have different consumption of capacity.

I don’t know how many hours it will be run every day. Can I choose a model first?
You can first make preliminary configurations based on approximate shifts and air volume, but the replacement cycle and maintenance schedule need to be supplemented with subsequent operating data before being revised. It is not appropriate to promise a fixed life in the absence of running hours.

Can Aili Industrial help organize the selection data?
It can be combined with air volume, inlet composition, shifts and operating periods to help sort out the data items that need to be supplemented. The specific configuration needs to be confirmed based on product information and on-site working conditions.

Related articles

• The gas concentration fluctuates greatly. Should the chemical filter be selected based on the average value or the short-term peak value?

• After the production process is adjusted, do the original chemical filtration requirements need to be rechecked?

• Can the cycle be extended after the chemical filter contamination load decreases?

• How long does it take for a chemical filter to be put into use after being unpacked?

Key points for selection and acceptance inspection