The media is where most collector problems begin and end. Temperature sets the shortlist; chemistry, moisture and dust behaviour decide between what remains.
Start With Four Questions
What is the excursion temperature? Not the running temperature. Media is destroyed during upsets, not during normal operation.
Does the gas stream carry moisture, and does it condense on shutdown? If yes, polyester and aramid are out regardless of temperature.
Is the dust sticky, hygroscopic or submicron? If yes, you need a membrane, whatever the substrate.
Is there acid, from sulphur in the fuel or from the process? If yes, PPS or PTFE.
| MEDIA | MAX CONTINUOUS | ABRASION | MOISTURE / ACID | TYPICAL DUTY |
|---|---|---|---|---|
| Polyester | 275°F | Good | Poor | General dust, ambient to moderate heat |
| PTFE membrane | Substrate | Moderate | Excellent | Sticky, hygroscopic, submicron |
| Aramid | 400°F | Excellent | Poor | Asphalt, foundry sand, dryers |
| Fibreglass | 500°F | Poor (flex) |
Excellent | Kilns, incinerators, boilers |
| P-84 | 500°F | Good | Poor | Fine particulate at high temperature |
| PPS | 375°F | Good | Excellent | Acid conditions, cycling processes |
| Pleated | Substrate | Moderate | n/a | Retrofit where ratio is too high |
The Mistake Worth Avoiding
Media is often changed in response to short bag life when the actual cause is the air-to-cloth ratio. A collector running too aggressively will destroy any media you put in it, and each upgrade costs more than the last while the interval barely moves.
Check the ratio against actual airflow before changing media. If bags are being replaced more than once a year and the interval is not improving, the specification is wrong somewhere other than the fabric.
Ratio corrected from 4.5:1 to 3.8:1 and PTFE membrane specified. Either alone would have helped; together they raised bag life 55% and halved maintenance hours.
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General guidance only goes so far. Send us the material and the process and we will tell you what we would specify.