What is a micron rating in filter bags?

A micron rating indicates the size of particles a filter bag can capture. One micron equals one-millionth of a meter. Filter bags with smaller micron ratings can filter out finer particles, enhancing the purity of the filtered liquid.

What is the difference between nominal and absolute micron ratings?

Nominal micron ratings refer to filters that remove a certain percentage (typically 50% to 80%) of particles of a specified size. Absolute micron ratings indicate filters that remove at least 98% of particles of the specified size in a single pass.

How do I choose the right micron rating for my application?

Selecting the appropriate micron rating depends on the level of filtration required. For coarse filtration, higher micron ratings (e.g., 50-200 microns) are suitable. For finer filtration needs, lower micron ratings (e.g., 1-10 microns) are recommended.

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Industrial liquid filtration systems utilize filter bags to ensure debris and unwanted contaminants are successfully separated and filtered from the fluid that passes through. The micron rating of the filter bag is the most essential factor in determining performance, cost, and filtration system longevity. Micron filtration ratings range from 1 to 1,000, with the number indicating the particle size that the bag can trap. Selecting the correct rating optimizes contaminant removal, maximizes flow rates, and extends service intervals.

What is a Filter Bag Micron Rating?

A micron (µm) is defined as one‑millionth of a meter. So, when a filter bag has an “µm” preceded by a number, it means that the bag will capture particles that size of microns or larger while allowing smaller particles to pass through. As the micron number decreases, filtration becomes finer. The bullet points below provide insight into how filter micron ratings work. All results are dependent on each application’s unique flow rate and viscosity.

Lower Micron (e.g., 5 µm): Traps very fine particles, higher purity, but greater pressure drop.
Higher Micron (e.g., 50 µm): Captures larger debris, higher throughput, lower pressure drop.

Micron Rating Applications: Coarse to Fine

With varying micron filtration rating numbers, it can often become confusing as to what the numbers mean and actually represent.
Examples of Filter Bag Usage

1-5 Micron Filter Bags

Micron filter bags with a rating of 1-5 µm are often used to filter applications that have critical purity requirements. Applications include:

Pharmaceutical & Biotech: Removal of sub‑visible particles in process water or media.
Food & Beverage: Sterile filtrations like juice clarification or dairy processing.
Electronics Manufacturing: Ultra‑clean rinse waters for semiconductor and PCB rinse tanks.

10 Micron Filter Bags

Micron filter bags with a rating of 10 µm are often used to filter applications that require particulate control with moderate flow or fine polishing. Applications include:

Chemical Processing: Catalyst recovery and fine solids removal in chemical syntheses.
Paint & Coatings: Removing lumps or pigment agglomerates to ensure smooth finishes.
Water Treatment: Pre‑RO or final filtration to protect membranes and deliver clear water.

25 Micron Filter Bags

Micron filter bags with a rating of 25 µm are often used for general-purpose filtration, helping to increase system efficiency and service life. Applications include:

Metalworking Fluids: Separating metal fines from coolant and lubricant mixtures.
Food Processing: Clarifying edible oils, syrups, or vinegar before bottling.
Industrial Wastewater: Primary solids removal prior to downstream treatment or discharge.

50 Micron Filter Bags

Micron filter bags with a rating of 25 µm are often used for coarse filtration, providing enhanced protection for pumps and heavy-duty equipment. Applications include:

Water Intake & Pre‑Filtration: Removing leaves, sand, and debris from raw water sources.
Pre‑Coat Protection: In front of finer filters to extend their life.
Construction & Mining: Separating large particulates in slurry and wash water processes.

Micron Ratings and Filter Efficiency

Filter efficiency is one of the most critical aspects of an industrial filtration system. The following sections detail how micron filtration ratings affect filtration efficiency and what that means for your specific filtration system.

Particle Removal Efficiency

5 µm Bags: High efficiency bags can remove >95% of particles down to 5 µm. Ideal for polishing or critical final‑stage filtration.
10 µm Bags: Capture most fine particulates (>90% at 10 µm), a balance of clarity and flow.
25 µm Bags: Effective at general solid removal (>85% at 25 µm), often used as a first or second‑stage filter.
50 µm Bags: Excellent for coarse debris (>80% at 50 µm), protecting downstream equipment from large contaminants.

It is important to determinize the effectiveness of the filter that you require. Filter bags and cartridges have various degrees of efficiencies that greatly affect cost, performance and filter sizing.

Flow Rate & Pressure Drop

Smaller Micron: Finer fibers, denser media → higher differential pressure at a given flow.
Larger Micron: More open media structure → lower pressure drop, higher flow capacity.

Filter Life & Maintenance

Fine Filters (1–10 µm): Load up quickly with particulates → shorter service life, frequent changeouts, and prefiltration is usually required.
Coarse Filters (25–50 µm): Hold more debris before clogging → longer intervals between replacements.

Filter Bag Options

Find the right filter bag for your application needs. Options include:

Filter Bag Resources

Check out our filter bag resources for a complete understanding of filter bags and their interactions with other industrial filtration system parts and components. Resources include:

Contact Rosedale Products for Premium Micron Rated Filter Bags Today

Rosedale Products is your trusted source for high-quality filter bags in various filter micron ratings. Contact us to let us help you with your filter bag material selection today. Our experts can provide you with decades of combined filter bag knowledge, providing an easy and effective way to get the filter bags you need.

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Filter Bag Micron Ratings – A Definitive Guide