Dear Meijden20,

The nature of the filterdefects is not explained in your thread.

The propsed, possible, solution of guard chains suggest that the defects have a mechanical origin (flyash hitting the filters directly).

If that is the case, the cause has to be eliminated and that could be a protective wall.

Other solutions are also possible, s.a. redirecting the flyash flow into the receiver by modifying the entrance direction.

If the damage of the filters is shown as being blown up, it can be that the filter cleaning pulses are to strong.

Filters also can get damaged by becoming too dirty (failing cleaning action) and then show as completely sucked flat.

Maybe, the filterload in m/min is designed too high, resulting in a lifetime of several months.

Is the vertical velocity between the filters low enough to prevent build-up of flyash between the filters?

Are the temperatures not too high?

If the pneumatic conveying system is designed at too high velocities (which often is the case),

then a solution to increase the life time of the filters could be decreasing the airflow.

In general, the way to deal with such a problem is to investigate the design, research the damage to its cause, and then work out a cure.

Is this problem occurring from the start or is it just emerging the last several months?

success

Teus ■

Dear meijden20,

Of course, the appearance of the defect can indicate the cause.

The observation that always the first few filterelements are concerned is important.

Assuming that the filter receiver geometry prevents fly-ash from direct hitting the filterelements, it might be possible that air pressure fronts impact the respective filterelements.

Those air pressure waves can be initiated by valves opening at high pressures, f.i. at the beginning of the conveying cycle of a batch.

Reducing such an opening pressure will decrease the pressure pulse but unfortunately also the conveying rate.

Dampening the pressure wave is also an option.

Looking into the filter receiver should also reveil the path, which is followed by the fly-ash, including possible bounce back to the filter.

Investigate, research, imagine, change simple things to check theories and don’t give up.

Met vriendelijke groeten

Teus ■

Dear meijden20,

You have not said what kind of filter/receiver or what kind of filters. (Fabric or cartridges)?

If the ash is directly impinging on the filters, a target plate (steel) opposite the pipe exit will give them some protection, (depending on the configuration of the filter/receiver). Such an arrangement is not uncommon when handling abrasive dusts.

Michael Reid. ■

For some applications metal filters which do not tear and are temperature tolerant may be an economical solution. These sintered metal elements can, with propper application, be "pulse jet" cleaned in-situ for coninuous use and un-interrupted flow, and in some hot-gas applications have lasted a year before they were removed for external cleaning before they were re-installed.

If you are interested in further reading and commercial information please visit the following links:

http://www.berr.gov.uk/files/file18804.pdf

http://www.porvairfiltration.com/lit...Separation.pdf

-Joseph ■