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Envelope Filter Bag
Envelope Filter Bag

Envelope Filter Bag

Basic commercial terms of Envelope filter bag:

Place of OriginShanghai, China
CertificationISO, FDA
Product ItemFlat Filter Bag
Minimum Order Quantity10pcs  (1pcs free sample)
PriceContact us to get an exact quotation
Packaging DetailsThe inner packing is in plastic bags
The outer packing is in carton
Large volume can also support custom packaging
Delivery Time7-30days after deposit. According to the specific order quantity.
1-7days for sample
Port of shipmentShanghai, Ningbo, Qingdao, Lianyungang, Guangzhou, Shenzhen or Others
Payment Terms30% Deposit, balance TT on copy B/L. Other payment methods can be negotiated according to the order requirements
Supply Ability:100000pcs/month
OEM/ODMYes, we can support customized, like size, shape, material
After-sales Services1 year warranty after we both sign the plant investigation usually for this one

What is an Envelope filter bag?

The shape of the filter bag is flat and rectangular. The supporting structure is a rectangular dust-proof framework with complete specifications. The thickness of the rectangular dust-proof framework is generally 25-50mm. This structure can make full use of the shell space of the dust filter compared to the cylindrical bag filter with the same volume. The filtering area is also larger.

The gap between the filter bags should not be too small, otherwise the filter bags will get easily blocked.

The envelope filter bag can be manufactured with different material like Polyester, Aramid, PPS, P84, Acrylic, PTFE, Fiberglass etc.

What are the special production processes for Envelope filter bags?

The flat filter bag is made of needle punched felt. The most traditional needle punched cloth on the market only requires acupuncture, singeing, heat setting, and rolling before use. However, in complex working conditions with special and high filtration requirements .Special production procedures can be used to improve the performance and efficiency of filter bags.

Filter bags can be treated with singeing, calendaring, water and oil repellent coating, PTFE impregnation and lamination as per customers demand and specifications.

Why Should You Choose SFFILTECH Envelope Filter Bag?

1. Reliable product quality

SFFILTECH has 3 production software and 22 advanced filter bag patents to ensure the efficiency and quality of filter bags

SFFILTECH strictly follows ISO standard production procedure and the regulations of automated production.

The production factory has a set of quality inspection procedures and a team of assisting personnel for pre-production, during production, and post production.

If required, a third-party laboratory quality inspection reports for each batch of products can be provided.

2. Convenient and stable shipment:

SFFILTECH has over 20 brand new filter bag production machines and equipment making the company capable of consistent production.

Stable and continuous supply and production. Large scale of storage of raw materials and accessories.

Independent warehouse provides a large amount of storage space for shipment stock.

Our company uses highly efficient transportation and courier services.

SFFILTECH has over 10 years of experience as a manufacturer.

3. Safe and reliable payment transactions:

Since its establishment, SFFILTECH has been cooperating with the most reliable banks in China, ensuring the safe funds transfer.

SFFILTECH supports multiple payment methods and can collaborate with third-party banks and enterprises to ensure the security of customer payment.

“Integrity has always been one of the most important concern of SFFILTECH”

4. Excellent pre-sales and after-sales service:

SFFILTECH has multiple experienced sales personnel providing 24-hour service.

SFFILTECH can provide instant online after-sales support as well as overseas after-sales services.

SFFILTECH has multiple agents worldwide and branches in some regions that can provide services in person.

When you need to replace an old filter bag

1. If you have the filter bag already in hand, then just take some picture for us first. Then we can get knowledge more than 80% if we can make.

2. If you can send us the samples, then we can analyses the sample bag material and treatment.

3. We can make one sample for you to try your bag house within a few days.

When you want to establish a new filtering system and need some advice

1. We will send you one investigation file for you to fill, all about your bag house condition, like temperature, chemical content and others. After you fill it back to us, we will suggest you one kind filter bag to try.

2. Our engineer can arrange one online with your engineer or plant investigation for you.

How to check what kinds of filter bag is suitable for the bag house?

When old filter bag requires replacement:

Once you remove the filter bag from the filter housing, you can just take some measurements and pictures to send them to us. We would be able know your filter bag specifications using this method.

If you are able send us the samples, we can analyse the sample bag material and treatment.

We can make a sample for you to test its fitment with your bag house within a few days.

When you want to install a new filtration system and need some advice:

1. We will send you a configuration to fill it according to your specifications and conditions like temperature, chemical content and others. After you send it back to us .We will inform you about what kind filter bag is suitable for you.

2. Our engineers can arrange online meeting with your engineer or provide you with the configuration based on your demand.

What are the advantages of Envelope filter bags?

The envelope type filter bag is mainly designed with multiple external shapes for the rotary reverse blowing flat bag dust collector. For this shape, it can achieve higher filtration efficiency, less land occupation, and longer service life of the filter bag.

What are the physical and mechanical properties of Envelope filter bags?

As the flat filter bag only changes the shape of the filter bag, it does not change the material. The performance parameters of the folding filter bag correspond one-to-one with the needle felt used.


What are the chemical properties of Envelope filter bags?

ItemFilter TypeContinuous
Resistance to
Resistance to
Resistance to AlkalisResistance to OxidationPH Value
AcrylicPolyacrylnitrile homopolymer125°C140°Cgoodgoodmoderategood3-11

What are the physical and mechanical properties of Envelope filter bags?

As the flat filter bag only changes the shape of the filter bag, it does not change the material. The performance parameters of the folding filter bag correspond one-to-one with the needle felt used.

What are the conventional size and weight parameters of Envelope filter bags?

Diameter (mm)Length (mm)Weight (g/㎡)
800, 9002000、3000、4000、5000、6000300, 350, 400, 450, 500, 550, 600, 650, 700, 800, 900
Most commonly used dimensions800mm*3000mm
Most commonly used weight450g, 500g, 550g, 650g, 700g
We can customize diameter, length, and weight for you

What industries are Envelope filter bags used in?

Specific applications of dust filter bags in various working conditions:

Where to install filter bag installed in each industrial plant?

Scope of application for filter bag Cement plant:

Crushing, grinding, coal grinding, material transportation, dust removal on the top of the warehouse, raw metal grinding, cement grinding, packaging.

Metallurgical plants:

Electric furnaces, blast furnaces, desulfurization furnaces, induction furnaces, casting, sandblasting, barrel furnaces.

Power plant:

Material conveyor, smoke (powder) dust treatment, fly ash storage.

Aluminum plant:

Fluidized bed dry cleaning tower, venturi jet dry cleaning tower, carbon dust, anode crushing, electrolytic aluminum production dust.

Food plant:

Fluidized bed dry cleaning tower, venturi jet dry cleaning tower, self-baking dry cleaning tower, carbon dust.

Food/pharmaceutical plant:

Additives, drying section, flour/grain processing, sugar and pesticide tablets, packaging.

Chemical plants:

Plastic fibers, resins, tires/rubber, coking, bleaching powder, packaging.

Each plant will have different filter bags. For more detail, we have the configuration file for you to select the right filter bag. Or you can visit us directly, we will provide you our assistance and guidance to you.


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