Product Review: Resin Treated Felt Gaskets

Custom resin treated felt circles and pads are cut to specified sizes and shapes and are used as gaskets and in a variety of filters. 

Resin treating the felt allows strengthens it, as well as adjusts the porosity for each individual filtration application.  This makes the felt impervious to the gas, oil, air or chemical being filtered.  Resin treated filters can act as gaskets used under pleated filters.

Dished felt piece can accommodate different depths, felt can be made to a specific shape shape.

Punch presses and dies create the perfect part.  A few applications for resin treated felt gaskets include, gaskets for refrigeration and air conditioning.

Dust Bags

Dust bags by Lamports can be used for a variety of filter manufacturers in materials including, but not limited to, polyester, FRP, Teflon and cotton. All OEM bags - any shape, any size.

  

A Sketch of Polypropylene Textile Cloths

Thank you to by: Walter Senney, Met-Chem Group President and Lamports Filter Media

One of the most popular fibers used to manufacture fabric today is polypropylene. It can be woven into a variety of thread counts to allow from loose to tight filtration applications. Polypropylene is good for use in temperatures from 50°F to 180°F (Specification charts show use up to 250°F under limited applications is acceptable, (but I would not recommend it). The acceptable pH range for products filtered with polypropylene material is 2- 12.  Polypropylene can be woven in the following ways:

• Multi-filament uses a number of fibers rolled together prior to weaving the cloth.  This allows for a smooth finish and normally tight filtration. This cloth is normally used for filtration in pressure leaf filters for chemicals, liquid foods and some lower solids wastewater; as well as for anode bags in plating applications.
  
  
• Mono-filament uses a single fiber (like fishing line) to weave the cloth. This allows for a slick non-absorbing cloth that can be used in the same applications as multifilament, but is normally not as tight for filtration.  This type of cloth works well for screening and more open filtration applications.
  
  
• Mono/multi filament blend is a cloth woven out of both fibers, one is woven in one direction, while the other is woven in the other direction. This cloth can give us the best of both worlds in terms of tight filtration and a slick face for ease of cake removal. One of the major uses of this cloth is on filter presses for process filtration and heavy solid waste water applications.  
  
• Felt is the needle punching of these fibers into a thick material used regularly for filtration of paints, coolants and a variety of liquids. Micron ratings can go nominally from 1-100. These felts can be supported by an internal scrim or they can be non-supported.  The supported felts can hang from a ring to filter, while the non-supported must be put in a pressure vessel supported by a basket to avoid blowout. 

This is just a thumbnail sketch of polypropylene textile cloths. These cloths can filter “the birds or the worms” depending on the type and tightness of the weave.

 

Yarn Fibers

Thank you to Murray Fabrics for Providing this Yarn Fiber Chart!

Murray Fabrics knits tubing out of a wide variety of yarns to fit each customer's individual needs. The different fibers can be used for corrosive situations whether you are dealing with chemicals, extreme temperatures, or fire safety, as well as simple filtration.

Knit tubing can be made out of the following yarn fibers:

Fabric Type	Characteristics
Polypropylene	Offers good tensile strength and abrasion resistance. They perform well in organic and mineral acids, solvents and alkalies. Polypropylene is attacked by nitric and chlorosulphonic acids, sodium and potassium hydroxide at high temperatures and concentrations.  pH range: 2-12 Temperature: up to 190° F
Polyester	Offers good resistance to most acids, oxidizing agents and organic solvents. Concentrated sulfuric and nitric acids are the exception. Polyesters are dissolved by alkalies at high concentrations. pH range: 2-9 Temperature: up to 325° F
Nylon	Good tensile strength and alkali resistance but is degraded by mineral acids and oxidizing agents. This reaction is accelerated at high concentrations and temperatures. pH range: 2-8 Temperature: up to 250° F
Cotton	Good abrasion resistance and mechanical strength. It is, however, subject to rot, mildew and shrinkage.  pH range: 3-10 Temperature: up to 225° F
Acrylic	The resistance of acrylic fibers is excellent in organic solvents, good in oxidizing agents, minerals and organic acids and fair in alkali. Will dissolve in sulfuric acid concentrations.  pH range: 4-5 *Subject to other variables  Temperature: 260 to 280°F / 125 to 135°C
Nomex*	Resist attack by mild acids, mild alkalies and most hydrocarbons.  Resistance to sulfur oxides above the acid dew point at temperatures above 300°F is better than polyester.  Flex resistance is excellent.  pH range:  2 - 12 Temperature: up to 425°F
Kevlar*	Kevlar (aramid yarn) is chemically stable under a wide variety of exposure conditions; however, certain strong acids and bases can cause degradation, particularly over long periods of time and at elevated temperatures. pH range: 5-7  Temperature: Max operating temp 300-500°F / 149-260°C (Does not melt until over 800°F / 427°C)

Stock Yarns: cotton, polyester, polypropylene, nylon, acrylic

Special Order Yarns: We can provide Kevlar, Nomex, flame retardant, polyester/cotton blend.

Quantity: Tubing is sold by the pound and is measured by flat width and stretch.

Pleated Filters

There is always something to consider when choosing filters. So let's discuss pleated filters today.

Pleated filters maximize filtration area for the space used.  These filters can have a variety of end caps;  epoxy, plastic, molded felt, custom. 

Some of these filter elements are self supporting while others have metal cores comprised of springs or screens. 

Applications for pleated filters include:

• Air intake filters for small gasoline engines.
• Freon gas filters for use in the refrigeration industry

Industrial Knitted Tubing

I've been talking a lot about the traditional filters, those filters that attach to something, are part of something, are high tech, sterile, or so many other types of filters. However there's another filter that I'd like to add to my blog; Knitted Tubing.

Although knitted tubing may be part of the many other filters, such as the covering on pleated filters, it it one of those very simple designs that are completely versatile and inexpensive. Also called stockinette, knitted tubing can make your more advanced filters last longer by catching the large particles before they get to the fine filtration.

But that's not it! Here are some examples of other knitted tubing uses:

• Chemical - chemical manufacturers use tubing to purify product throughout process
• Fire Safety - flame retardant sleeves and cuffs as protective layers
• Medical - non-sterile utility items
• Filtration - filter bags, filter tubing, and filter covers
• Paint - manufacturers use long filter bags to remove paint particulate before packaging
• Paint spray booths - protective sleeve, cap, or skin cover
• Manufacturing plants - use abrasion resistant sleeves to protect employees
• Construction - use wide tubing to filter solids out of run-off
• Automotive After Market - to protect parts in transit

Resistance Chart

I found a cool site with a fabric resistance chart:

Fiber	Tensile Strength	Abrasion Resistance	Chemical Resistance		Deg F		Deg C		PH
			Acid	Alkali	Cont.	Surge	Cont.	Surge
Polypropylene	Excellent	Good	Excellent	Excellent	190	190	90	90	2-12
Polyester	Excellent	Excellent	Good	Fair	275	325	135	150	2-7
Nylon	Excellent	Excellent	Poor	Excellent	200	250	90	120	2-8
Polyethylene	Good	Very Good	Excellent	Excellent	122	176	50	80	2-12
Cotton	Good	Average	Poor	Excellent	180	225	80	105	3-10
Nomex	Very Good	Very Good	Fair	Good	400	425	200	215	2-12
Teflon	Fair	Good	Excellent	Excellent	450	500	230	260	Any

NOTE: This table is only a general guide.  Operating temperature, chemical concentrations and mechanical conditions all have a pronounced effect on service life.