
Frequently Asked Questions​
Before selecting a filter media, you should first identify the chemical and thermal make-up of the fluid you are processing. You can then determine what materials are thermally and chemically compatible with the process. Once you have determined what type of fibre is compatible with the process fluid, determine the type of filtration you want to perform: depth filtration is accomplished with nominally rated felts, surface filtration uses a precise woven mesh. All materials are micron rated to enable the selection of the correct media and achieve the desired level of filtration.
There are many types of liquid filtration, of which, liquid filter bags and cartridges are two of the most common. While all methods of filtration have their benefits, filter bags are known as an inexpensive, user-friendly solution and are very effective for high flow rate and high dirt load applications.
Differential Pressure (often displayed as PSID, Delta P or ΔP) is the pressure that is created across the filter as the contaminate builds up. The differential pressure is calculated by subtracting the downstream pressure (after the filter) from the upstream pressure (before the filter). Differential Pressure is used as a means of identifying when a filter bag should be changed. The recommended change-out for a filter bag is ΔP = 25 psi.
"Micron" is a metric unit of measurement defined as 1/1000 of a millimeter (1/24000 of an inch). It is interesting to note that the smallest particle visible to the human eye is 40 microns in size.
Contaminate consists of a wide range of particulate. Knowing the size and quantity of contaminate as well as the level of filtration to be achieved (i.e. the quantity of contaminate to be removed from the process stream) is important information in selecting the appropriate filter micron rated media.
IFM's steel ring bag with side-welded seam is a revolutionary modification that reduces bypass by eliminating the "Lump" common to the standard steel ring fully sewn bag.
The Polyform SEAL plastic flange has superior sealing capabilities as compared to steel rings and eliminates the possibility of bypass. In addition, the plastic flange has the advantage of integrated plastic handles for easy bag removal as well as providing the option of a fully welded filter bag. Note, however, that the thermal and chemical compatibility of the filter materials with the process fluid should be considered.
Filter bags are basically a two-dimensional flat tube with a collar. It must fill up void spaces of a three-dimensional support basket; therefore, the width of the bottom of the basket is incorporated in the length of the bag. The filter bag must be supported by the basket in order to achieve the maximum differential pressure capacity and prevent bag failure.
In some instances, returns of clean, unopened, filter bags can be accepted with a restocking fee. Acceptance of returns is dependent upon our ability to resell the filter products. Due to the multitude of combinations of media, micron rating, sizes and options, it may be impossible to resell certain bag configurations.
Flow rate capacity is dependent upon a number of process variables such as pressure, viscosity, dirt loading, and desired particle retention rate. Maximum flow rates for standard filter bags based on clean water are listed in the flow rate chart.
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