A very useful type of diesel particulate filter element consists of ceramic fibres wrapped around a perforated metal tube, which doubles as a heater element. This type was developed by the 3M company in the 1990s and was integrated into a filter system known as ‘STX’ by the Engelhard Corporation. Although its filtration efficiency is not as good as more modern types of filter element, it offers two major advantages, as follows:
- The built-in heater element facilitates active regeneration
- If the filter becomes full of soot, the engine will still run (but the filtration efficiency will be zero)
These elements are now only available in one size, 70mm diameter by 250mm long, and one element is required for approximately every 5 kW of engine power, therefore they are best suited to small engines. Each element requires a 12 volt power supply (AC or DC) at 50 Amps to regenerate it, so if they are wired in series, two elements can be regenerated from a 24 volt supply, nine from 110 volts and 20 elements from 230 volts. The power supply can be either mains or battery, therefore they are ideal for hybrid generators.
The filtration efficiency varies according to how full the filter element is, but we have succeeded in getting the particulate emissions on an 898cc Kubota down to 2.65 mg/kW-hr using four elements.
They can also be used in conjunction with fuel-borne catalysts.
Blackthorn has over 10 years’ experience with these filter elements, and probably the only remaining stocks in the World. We are happy to supply just the elements to companies which have the engineering capabilities to utilise them, or complete filter systems based around them.
Blackthorn has developed systems incorporating two, four, nine and 20 filter elements. Further information about each of these can be found by following the menu on the right.