An oil-water repellent polyester filter bag can improve cake release in medium-temperature processes affected by moisture/aerosols; it should not be thought of as a chemical-resistant media.
What Is an Oil-Water Repellent Polyester Bag?
Water- and oil-repellent polyester filter bag is a version of PES felt reinforced with a hydrophobic/oleophobic finish. The goal is to reduce dust cake adhesion to the felt caused by water droplets, light oil/aerosol, or moisture, and to keep dP behavior more stable.
When Do I Need It?
| Condition | Comment | Control |
|---|---|---|
| Moist mineral powder | A WOR surface treatment can help | Dew point and temperature |
| Oil/aerosol trace | An oleophobic finish can be considered | Gas analysis |
| Dry standard powder | It might be unnecessary. | dP trend |
| Aggressive chemistry | But it’s not enough.” | Media chemical resistance |
The Difference Between PES WOR and Membrane
WOR finish improves the surface's water/oil repellency; an ePTFE membrane, on the other hand, forms a different layer for surface filtration and fine-particle capture. For fine 1-3 µm dust and a low emission target, a membrane can be the stronger candidate; for a purely moist-cake problem, WOR alone may be sufficient.
When Would I Not Use It?
Example
Example
- Process
- Cement packaging
- Heat
- 90°C
- Dust
- Fine alkaline
- Symptom
- dP increase on humid days
- Approaches
- PES 500 glaze WOR + pulse and humidity control
Information for Bid
Moisture source, temperature, dust type, dP trend, emission target, bag size, cage, and existing surface treatment should be specified. You can submit this data via the quote form. Related articles: PES bags, PTFE membrane.
Frequently Asked Questions
Is a WOR bag waterproof?
This is a process filter finish and should not be read as a guarantee of absolute waterproofing.
Can a WOR bag replace a membrane bag?
No. For fine-particle/low-emission targets, the membrane is evaluated separately.
Engineering Selection Parameters: Media Name Alone Is Not Enough
When selecting a filter bag, the media name is only a starting point. The same water-oil repellent polyester / WOR PES bag can run stably under a low A/C ratio, dry dust, and a properly functioning pulse system, but under high airflow, a damp cake, a poor cage, or an incorrect snap-band size, it can develop a dP or emission problem within a short time. That is why, in Hantech's evaluation, the bag is read together with the fan, filter area, cage, cell plate, pulse valve, and hopper behavior.
| Parameter | - why it is critical | Data requested for the quote |
|---|---|---|
| Normal / peak temperature | Media aging, shrinkage, and seam strength | Shift records, alarm history |
| Moisture and dew point | Sticky cake, hydrolysis, or chemical aging | Gas moisture, insulation, start-stop behavior |
| Gas chemistry | SOx/SO3, NOx/NO2, HCl, HF, O2, and an alkaline environment change media life | Gas analysis or process recipe |
| Powder micron distribution | 1-3 µm dust embeds into the felt; coarse abrasive dust wears down the housing | Particle analysis or site observation |
| A/C ratio | High filtration velocity causes rising dP and short bag life | Flow rate, bag diameter-length-count |
| dP trend | Indicates blinding, leaks, or inadequate cleaning | Pa/mmWG chart after new bags |
| Cage outer diameter and surface | Incorrect OD, burrs, or rust mechanically abrade the bag | Cage photo, OD, wire count |
| Snap-band / cell plate | Mouth leakage produces low dP + high emissions | Hole diameter, sheet thickness, bead detail |
This approach matters especially for oil-and-water repellent polyester / WOR PES, because on site the problem often looks like 'bad media' when the root cause may actually be the A/C ratio, pulse energy, moisture, cage surface, or collar sealing.
Which Field Symptom Changes Which Decision?
| Site indication | Possible root cause | Hantech approach |
|---|---|---|
| dP rises above 1800-2200 Pa after new bags | High A/C, fine dust penetration, moist cake, or weak pulsing | Surface treatment/membrane need and filter area are checked together |
| Low dP but dust at the stack | Filter bag tear, snap-band leakage, or bypass | Cell plate, collar detail, and cage contact marks are checked |
| Vertical wear on the filter bag body | Cage burrs, incorrect OD, or bag chafing | Bag performance cannot be upgraded without replacing the cage surface and wires/rings |
| Dust traces at the filter bag top | Snap-band isn't seating properly, or sheet thickness is wrong | Double cord, band size, and hole tolerance are re-measured |
| dP increases on humid days | Dew point, condensation, or sticky cake | Thermal insulation, hydrophobic surface, and process control are evaluated together |
This table is used at the quoting stage to avoid selling the customer an unnecessary premium media. If the symptom stems from a mechanical or process issue, choosing a more expensive bag will not be a lasting solution.
Comparison with Alternative Media
WOR is an economical surface treatment positioned between standard PES and ePTFE membrane, focused on moisture/cake release. Hantech's approach is not to push a single brand or the most expensive option, but to balance the most economical and safe solution that is sufficient against the process risk.
| Comparison criterion | Comment for this media | Alternative decision |
|---|---|---|
| Heat | Since the base media is PES, the 110–140°C normal / 150°C short-peak discipline is maintained. | If the limit is exceeded, a higher-grade media is considered |
| Fine dust / low emission | A need for surface treatment or a membrane can arise | ePTFE membrane, P84, or PTFE is compared |
| Moisture / acid | Media chemical resistance is not read on its own -- it's assessed together with dew point | Options such as PPS/PTFE/fiberglass PTFE may be required |
| Mechanical risk | Cage and installation errors can ruin even good filter media | The cage/snap-band/pulse system is corrected first |
| Expense | Premium media is selected only when there is a real risk or target | Adequate candidates such as PES/PPS/Aramid are not ruled out |
I Would Not Choose Oil-and-Water Repellent Polyester / WOR PES Under These Conditions
Worked Example: A Cement Packaging Filter with Rising dP on Humid Days
Sample account and comment
- Flow Rate
- 60,000 m³/h
- Bag size
- Ø160 x 6,000 mm
- Number OF bags
- 240
- One bag area
- π x 0.16 x 6.0 = 3.02 m²
- Total Area
- 240 x 3.02 = 724.8 m²
- Gross A/C
- 60,000 / 60 / 724.8 = 1.38 m/min
- First decision
- Oil-and-water-repellent polyester / WOR PES is evaluated based on dust micron size, moisture, and dP trend
This example value is not good or bad on its own. 1.38 m/min may look acceptable for dry, medium-grain mineral dust, but risky for fine (1-3 µm), sticky, or moist dust. If dP rises quickly after a new bag is installed, the surface finish, pulse energy, filter area, and inlet distribution should be reviewed together, not just the media.
WOR PES is an economical intermediate solution for processes at moderate temperature where cake release is disrupted by moisture or aerosol effects. However, this choice should not be turned into a firm quotation until cage surface and snap-band fit are verified.
RFQ / Quotation Checklist
A complete quotation for oil-and-water repellent polyester / WOR PES bags requires more than just dimensions and quantity. The minimum data set is: bag diameter, bag length, quantity, top connection type, bottom cap detail, current media and weight (gsm), surface finish, normal/peak temperature, moisture or dew-point risk, gas chemistry, dust type, particle size distribution, dP trend, target emission level, cage outer diameter, cell-plate hole, sheet thickness, pulse pressure, and photos of the current bag/cage.
Once this information is available, Hantech evaluates filter bags, filter cages, pulse-jet valves, and if needed performance measurement together. You can submit the data via the quote form.
Technical Review Note
Technical review: Doğuhan Kırmacı — industrial filtration, dust collection systems and filter bag selection applications.
This content has been prepared by comparing process data, manufacturer technical limits, field failure behavior, and bag-cage-pulse compatibility. The values here are for preliminary selection; the final selection must be verified against the manufacturer's datasheet, site measurements, and process conditions.