Method and apparatus for cleaning tube type fabric filters

Claim 2

The method of cleaning tubular fabric type filter elements of claim 1 in which selected filter elements have air curtains created at the extremities of the same while the remainder of the filter elements receive contaminated air to maintain a normal filtering operation therethrough and in which the airflow through the filter elements in the normal filtering operation creates an outside air pressure on the filter elements having the air curtain created therein and a reverse airflow into said filter elements to coact with the reduced internal air pressure therein.

Claim 3

The method of cleaning tubular fabric type filter elements of claim 3 in which The selected filter elements having the air curtains created at the extremities of the same are periodically changed with filter elements subjected to a normal filtering operation and in which there are only ten to fifteen percent of the filter elements of a group of filter elements being cleaned by creating the pulsed air curtain therein while the remainder of the filter elements are subjected to contaminated air in a normal filtering operation.

Claim 4

The method of cleaning tubular fabric type filter elements of claim 4 in which the steps of creating pulsed air curtains in the tubular filter elements being cleaned are repeated several times before selecting other filter elements for cleaning.

Claim 5

A filtering apparatus comprising a framed enclosure, a plurality of tubular fabric type filter elements open at both extremities and positioned within said framed enclosure, a first divider plate positioned in the framed enclosure and having a plurality of openings therein with said first plate mounting the upper extremity of each of said filter elements at said plurality of openings, a second divider plate positioned in the framed enclosure having a plurality of openings therein and mounting the opposite extremity of each of said filter elements to position the filter elements in the elongated vertical position, means including the framed enclosure connected to the second divider plate and defining a dust chamber located beneath the second divider plate and having a discharge opening therein, means included in said framed enclosure and with at least one of said divider plates defining a sealed plenum chamber through which air is directed to the filtering operation of the filtering apparatus, means connected to the plenum chamber for causing contaminated air to be directed into the filtering elements of the filtering apparatus at the open upper extremities thereof and through the walls of the filtering elements with the particulates being collected on the inner walls of the tubular filtering elements, and means including a high pressure air supply and associated with the open extremities of each of the tubular filtering elements for selectively creating outwardly directed pulsed air curtains at the ends of each of selected filtering elements and out of the filter elements to block airflow therethrough and create a drop of pressure within said selected filtering elements causing collapse of said selected filtering elements to remove particulates from the inner walls thereof and causing the particulates to be directed into the dust chamber with the force of gravity thereon.

Claim 6

The filtering apparatus of claim 6 in which the means including the high pressure air supply and associated with the tubular filtering elements create the air curtains at the extremities of the tubular filtering elements and include a jet nozzle positioned at the upper extremity of the bag type filters and directing air therefrom to form the air curtain at the inlet extremity of the tubular filtering element with additional nozzle means directing air to form an air curtain at the other extremity of the filtering element.

Claim 7

The filtering apparatus of claim 7 in which the additional nozzle means includes a nozzle pipe extending part way through the filtering element from the jet nozzle and directed toward the other open extremity of the filtering element to create the air curtain at said other extremity of the filtering element.

Claim 8

The filtering apparatus of claim 6 in which the means including the high pressure air source and associated with the open extremities of the tubular filtering elements includes nozzle means positioned at the open extremities of the filtering elements and adapted to receive high pressure air simultaneously from the source to create air curtains simultaneously at the extremities of the filtering elements.

Claim 9

The filtering apparatus of claim 9 in which the nozzles which direct air out of the confines of the filtering element create a pumping action therein and the drop in Pressure within the filtering element.

Claim 10

The filtering apparatus of claim 10 in which the nozzle means at each extremity of the filter element are connected to a common manifold and to the high pressure air supply through a valve which controls simultaneous flow from the high pressure air supply to the nozzle means at each extremity of the filtering element.

Claim 11

The filtering apparatus of claim 11 and including control circuit means connected to each of the control valves to selectively operate the same in a programmed sequence in which only a single valve for the plurality of filtering elements will become operative at one time and with a series of periodic pulsed operations while the remainder of the valves remain inoperative and in which a different valve is operated thereafter until all of the valves have become operative to cause air curtains to be created at the extremities of the respective filter elements in a continuous filtering and cleaning operation of the filtering apparatus.

Claim 12

The filtering apparatus of claim 6 in hich the plenum chamber is formed between the first named divider plate and the framed enclosure and surrounding the openings in the divider plate to define the inlet side of the filtering apparatus common to the open upper extremities of the filtering elements.

Claim 13

The filtering apparatus of claim 6 in which the plenum chamber is located between and connected to the first and second named divider plates enclosing the filtering elements extending therebetween and defining the outlet side of the filtering apparatus.

Claim 14

The filtering apparatus of claim 6 in which the framed enclosure and the first and second named divider plates define a second plenum chamber extending between the divider plates and surrounding the filtering elements extending therebetween defining an outlet of the filtering apparatus with the means causing contaminated airflow to be directed into the filtering elements being connected to one of the plenum chambers.