Common materials and characteristics of normal temperature dust filter bags
In industrial dust removal systems, filter bags are the core filter components of bag dust collectors, and their performance directly affects the dust removal efficiency and system operation stability. For normal temperature (generally refers to ambient temperature below 120°C) working conditions, such as woodworking, food, light industry, pharmaceuticals, mechanical processing and other industries, it is particularly important to select suitable normal temperature filter bag materials. Normal temperature dust filter bags are mainly based on synthetic fibers and natural fibers. The following are several common filter bag materials and their performance characteristics:
1. Polyester needle felt (polyester)
Features:
Working temperature: ≤130°C, instantaneous temperature resistance can reach 150°C
Acid resistance: general
Alkali resistance: general
Abrasion resistance: excellent
Cost: relatively low
Advantages:
Polyester needle felt is the most commonly used normal temperature dust removal filter material, with economical price, good processing performance, and high mechanical strength. It is widely used in cement, wood industry, machinery manufacturing, grain processing and other occasions where dust concentration is not high and there is no strong corrosive gas. The surface of the filter material can be treated by singeing, calendering, laminating, etc. to improve the filtration accuracy and cleaning effect.
Disadvantages:
Poor high temperature resistance, low tolerance to strong acids, strong alkalis and flue gas containing oxidants, and easy to hydrolyze and age.
2. Polypropylene needle felt (polypropylene)
Features:
Working temperature: ≤90℃
Acid and alkali resistance: excellent
Hydrolysis resistance: good
Cost: low
Advantages:
Polypropylene filter bags have strong tolerance to acid and alkaline dust and low hygroscopicity. They are suitable for environments with high humidity or acid and alkali corrosive dust such as chemical, pharmaceutical, and food. Its low density and light weight can reduce the load of dust removal equipment.
Disadvantages:
Poor heat resistance, slightly weaker mechanical strength than polyester, not suitable for high temperature or high load conditions.
3. Acrylic needle felt (polyacrylonitrile)
Features:
Working temperature: ≤120℃
Chemical resistance: good, medium acid and alkali resistance
Cost: above average
Advantages:
Acrylic needle felt has good chemical corrosion resistance, especially for acidic gases, and is suitable for fertilizers, garbage disposal, spray drying and other occasions with corrosive flue gas but low temperature. Its oxidation resistance and hydrolysis resistance are better than polyester and polypropylene.
Disadvantages:
The cost is higher than polyester and polypropylene, the tensile strength is average, the wear resistance is slightly poor, and it is not suitable for working conditions with high mechanical wear.
4. Blended needle felt
Features:
Usually blended with polyester, polypropylene, acrylic or other fibers
Performance is adjusted according to the ratio
Advantages:
The comprehensive performance of the filter material is improved by combining different fibers. For example: polyester + acrylic blending can improve chemical resistance and mechanical strength, and adapt to more complex working conditions. Blended filter material can achieve a good balance between cost and performance.
Disadvantages:
The performance is limited by the fiber ratio, and the aging speed of different fibers may be inconsistent during long-term use.
5. Cotton cloth/polyester cotton cloth
Features:
Working temperature: ≤80℃
Natural material, good air permeability
Cost: low
Advantages:
Widely used in grain, food processing, woodworking and other industries in the early days, it is still used in some simple dust removal equipment because of its softness, breathability and low price.
Disadvantages:
It is easy to absorb moisture and mold, has low strength and wear resistance, is not suitable for automatic dust cleaning or pulse spraying system, is easy to clog and has a short service life.
6. Coated filter material (such as polyester base cloth coated with PTFE membrane)
Features:
Smooth surface and high filtration accuracy
Temperature resistance depends on the base cloth, generally ≤130℃
Advantages:
The coated filter bag has a very strong surface filtration ability and almost does not need to rely on the dust layer for filtration, so it has low resistance, fast cleaning and high efficiency. It is suitable for industries with strict requirements on dust emissions, such as food, medicine, fine chemicals, etc.
Disadvantages:
High cost and high requirements for processing technology.
Summary
Material Temperature resistance (℃) Acid and alkali resistance Abrasion resistance Cost Typical application
Polyester ≤130 General Excellent Low Woodworking, building materials, machinery
Polypropylene ≤90 Excellent Medium Low Chemical, humid environment
Acrylic ≤120 Good General Medium High Garbage treatment, spray drying
Blended according to the ratio Adjustable Adjustable Medium Various working conditions
Cotton cloth/polyester cotton ≤80 General Low Low Food, grain
Coated polyester ≤130 Excellent Excellent High Pharmaceutical, fine chemical
In actual application, the most suitable filter bag material should be selected according to comprehensive factors such as dust properties, gas temperature, humidity, chemical composition and dust removal equipment structure to ensure efficient, economical and safe operation of the dust removal system.
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