Filter Bag Material Selection

In the "respiratory chain" of industrial production, dust collectors are the "purifiers" that protect the air in the workshop, and the filter bags (or cartridges) are the "heart" of this equipment.

Can dust be efficiently captured? Will the equipment frequently malfunction? Are maintenance costs high? It all depends on the filter bag's "protective layer." Especially in workshops that are humid, oily, or where dust is flammable and explosive, the waterproof, oil-proof, and anti-static properties of the filter bag directly relate to production safety and environmental compliance.

we'll get straight to the point, discussing everything from filtration principles to material selection, and then applying it to real-world scenarios, thoroughly explaining the intricacies of filter bag selection!

I. First, understand: The core logic of filter bag filtration is not as simple as a "sieve"

Many people think that filter bag filtration is the same as a sieve at home, relying solely on pore size to "sieve" dust – this is only half true. Industrial filter bag filtration involves two stages, and the principle is more complex than imagined:

Stage 1: Initial Filtration

Dust particles collide with the filter bag along with the airflow. Large particles are blocked due to inertia, while smaller particles "stick" to the filter material fibers through Brownian motion. At this stage, the filtration efficiency is relatively low, and some dust may occasionally penetrate.

Stage 2: Stable Stage

The attached dust gradually forms a "dust layer," and this "dust film" is the real "filtration expert"! Even tiny dust particles can be firmly blocked, maximizing filtration efficiency.

The waterproof, oil-proof, and anti-static properties we often talk about are essentially to protect this "dust layer":

Waterproof and oil-proof → Prevents dust from clumping together when encountering oil or water, disrupting the "dust layer";

Anti-static → Prevents dust from accumulating static electricity due to friction, eliminating the risk of explosion.

These three properties directly determine how long the filter bag will last and how safe the workshop will be.

II. Key Points: A Comparison of the "Three-Resistance" Performance of 4 Mainstream Materials

The core materials of industrial filter bags are all synthetic fibers, but their performance varies greatly due to differences in molecular structure and manufacturing processes. Let's focus on the four most commonly used materials:

1. Polyester (PET): The King of Cost-Effectiveness, the go-to choice for basic working conditions

Core advantages: Affordable price (market price 10-20 yuan/piece), temperature resistance up to 130℃, suitable for 80% of dry dust working conditions.

Water and oil resistance: Achieved through "water and oil repellent finishing agents," with good initial effect, but long-term contact with oil mist/high humidity environments will cause wear and tear, reducing protective performance.

Antistatic: Requires the addition of conductive fibers/carbon black modification. After modification, the surface resistance is 10⁶-10⁹Ω, meeting the basic antistatic requirements for flour, feed, etc.

Shortcomings: Not recommended for high-risk flammable and explosive working conditions (high concentration of coal dust, aluminum powder); shorter lifespan (6-12 months).

Applicable scenarios: Cement, building materials, grain processing, and other dry, low-risk workshops.

2. Polypropylene (PP): The Acid and Alkali Resistance Expert, exclusive for high-humidity conditions

Core advantages: Non-polar molecular groups, naturally waterproof! Acid and alkali resistance far surpasses polyester, and the price is slightly lower than polyester.

Water and oil resistance: Waterproof without treatment, easily handles high humidity; however, poor oil resistance, and large amounts of oil mist will clog the filter bag.

Antistatic: After modification, the surface resistance is similar to polyester, but the temperature resistance is only 90℃, and it is prone to softening and deformation at higher temperatures.

Shortcomings: Avoid oily working conditions (not suitable for machining and metal cutting), low temperature resistance.

Applicable scenarios: Chemical, electroplating, sewage treatment, and other workshops containing acids and alkalis and high humidity.

3. Polyphenylene Sulfide (PPS): The High-Temperature Workhorse, with excellent overall performance

Core advantages: Temperature resistance up to 190℃, the "workhorse" for high-temperature conditions; PTFE coating forms a "non-stick layer," making it difficult for water and oil to adhere.

Water and oil resistance: Has basic protection itself, and after coating, it can operate stably in sulfur-containing wet flue gas, with a lifespan of 2-3 years. Antistatic: Modified with conductive particles, providing long-lasting antistatic performance and resistance to high-temperature static electricity accumulation.

Disadvantage: The price is 3-5 times that of polyester; the operating costs need to be carefully calculated.

Applicable scenarios: High-temperature, humid, and sulfur-containing workshops such as coal-fired boilers, waste incineration, and coking plants.

4. Polytetrafluoroethylene (PTFE): Ultimate protection, a savior for extreme working conditions

Core advantages: Commonly known as "Teflon," it withstands temperatures up to 260℃, is resistant to acids, alkalis, and oils, and provides almost permanent water and oil resistance.

Water and oil resistance: Extremely high chemical stability; no corrosive medium can erode it, eliminating concerns about caking and blockage.

Antistatic: Internal conductive network design prevents explosions in high-risk dust workshops such as aluminum processing and magnesium alloy manufacturing.

Disadvantage: The price is 10 times that of polyester; not recommended for non-extreme working conditions.

Applicable scenarios: High-risk workshops such as those involving strong chemical corrosion, high-temperature aerospace applications, and metal powders.

III. Practical Guide: Directly Match Your Needs to These 3 Typical Scenarios

Selection Core Principle: Don't buy the most expensive, buy the most suitable. Matching performance to working conditions ensures both safety and cost savings. Here's the practical advice:

1. Ordinary Drying Conditions (Cement, building materials, etc.)

First Choice: Ordinary polyester filter bags (the best value for money)

✅ Upgrade: If there is slight static electricity (e.g., grain processing), choose anti-static modified polyester.

2. High Humidity/Acid-Base Conditions (Chemicals, electroplating, etc.)

Basic: Polypropylene filter bags (naturally waterproof + acid and alkali resistant)

✅ Upgrade: For temperatures between 100-180℃, switch to PPS filter bags (high-temperature resistant "acid and alkali king")

3. Oil-Containing/Flammable and Explosive Conditions (Machining, aluminum powder, etc.)

✅ Low-temperature oil-containing (<90℃): Oil-resistant modified polyester

✅ High-temperature oil-containing (>90℃): PTFE coated PPS

✅ High-risk explosive (high concentration metal powder): Directly use PTFE anti-static filter bags

Two tips to avoid common problems:

Control the filtration air velocity: For oily and humid conditions, do not exceed 0.8 m/min.  Excessive air velocity will accelerate filter bag wear and coating detachment;

Choose the optimal cleaning method: Pulse cleaning causes significant damage to filter bags; try to choose an offline cleaning system to extend their service life.

Although filter bags are small, they are the "last line of defense" in industrial dust removal – choosing the right ones means fewer equipment malfunctions and worry-free environmental compliance; choosing the wrong ones not only wastes money but may also create safety hazards.

Source: Hanheng Environmental Management Official Account

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