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Filter Specification

  • Significantly greater filter life
  • Greater efficiency
  • Filters have closed cell polyurethane seals
  • Not affected by carbon and moisture
  • Developed in conjunction with Mira since 1980
  • Used by the vast majority of the UK bus industry with current production requirements running at over 1000 units per week.
  • Available in multi-stage "5 series"
  • Initial cost on many types, is less expensive than good quality paper filters.
  • Reticulated polyurethane produced within ±2 pores and reticulated by gas blown
    method, NOT chemically.
  • All filters and engines covered by FCL unconditional warranty.
  • Full test and backup facility available in our in-house test laboratory.
  • All filters treated synthetic plastisizer.
  • Outer layers have patented dimple profile.

Warranty Statement
FCL filters are guaranteed to be free from any defect in workmanship and materials during the service life recommended and if found to be defective will be replaced .Vehicle and engine warranties cannot be voided solely due to the use of FCL filters. This warranty does not cover failures caused by misuse, faulty installation, alteration, or accident. In the event of engine failure directly attributable to a FCL filter defect ,FCL will restore the engine to a condition equivalent to that existing just before the failure. However, FCL is not liable for any other losses or expenses incurred due to such defect.

Managing Director
Deryck Norville

Filtration Standards

Series 5
There are now two recognized standards in Filtration media. They are:

  • Pleated Paper
  • Reticulated Polyurethane

Although the basic construction to these elements are similar, the performance characteristics and benefits are extremely different.

1 - Pleated Paper
These elements rely on the dust contaminant particles being sieved through small holes in the surface of the paper. This is known as a surface media as all filtration occurs at one surface.

Under test facilities, an element is tested under constant airflow and high dust concentrations, where dust will quickly build up on the surface and become an integral part of the filter.

However, in real life situations the airflow is variable due to the change in engine RPM. This will give a considerably different set of results as dust build up is much slower and vehicle vibration will shake dust off the surface. This gives the effect of prolonging the low initial efficiency of the paper media for much longer. If the filters are changed To regularly then the engine is not being protected to the same standards as if the filter was left in as long as possible.

Premature failure can be experienced with pleated paper as hydrocarbons (exhaust fumes) can quickly block the surface, causing a rapid increase in restriction on the filter.

Also damp conditions can cause the paper to swell, blocking the pores and increasing the restriction. Continual running in damp conditions causes the paper to swell and contract due to the drying out effect of the airflow ,leading to the cracking of the paper at the base and tip of the pleat. All protection to the engine will be lost.

2 - Reticulated Polyurethane
These elements are made from 3 to 5 layers of different porosities starting open / coarse porosity on the outside to a virtually closed / fine porosity on the inside. The polyurethane layers are like an ever tightening honeycomb that grades the particles from the course to fine as the air passes through the filter. This is known as a depth media.

To achieve high levels of efficiency required to protect an automotive engine, the polyurethane has to have a special additive coated on to the surface of the strands of polyurethane. This is so that the dust particles can stick to the polyurethane and become part of the filter. The particle will then soak up the additive and become wet allowing further dust particles to stick to it. This is known as wetting.

The initial efficiency of a polyurethane element is considerably higher than that of a paper element and will offer greater protection for most of it's life than a paper filter.

Under test conditions of constant flow and high dust concentrations, the polyurethane air cleaner will not achieve as much dust holding as in real life, because the wetting process is not achieved due to the short time scale that the test is carried over. Vibration of the vehicle will not effect the efficiency of the polyurethane element as the dust is permanently bonded to the polyurethane.

Hydrocarbons will not prematurely fail a polyurethane filter as it is easily absorbed into the matrix of the polyurethane. Due to the plastic construction of the filter, it is totally unaffected by water and in damp conditions will retain maximum protection.

Checking Filter Condition
It has been recognized practice in the industry to check filters visually. Although this will give a rough indication of the filter condition, it is totally inaccurate where polyurethane filters are concerned, as they tend to look dirty very quickly with no increase in restriction.

The only accurate way of checking filter condition is to measure it's ability to flow air. In the past, this has been determined by a pop-up gauge where a clear portion in a gauge changes to red by a plunger when a set restriction is reached. This is not practical as it is like having a light on the dashboard telling you when you have run out of fuel. What is required is a graduated scale so as the restriction increases on the filter, it can be monitored and fitters can easily identify when the filter is reaching the end of it's life.

FCL supplies this type of indicator / minder and it has the added bonus of locking off at various points on the scale so the highest restriction, (at maximum airflow) , is always monitored.

Using a graduated indicator will give an increase in life on a paper filter but an outstanding increase in life of a polyurethane cleaner.

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