Air filtration system

• US 5,409,512 A
• Filed: 11/10/1993
• Issued: 04/25/1995
• Est. Priority Date: 11/10/1993
• Status: Expired due to Term

• Current Assignee: Schwarze Industries, Inc. (Alamo Group Incorporated)
• Original Assignee: Commerical Sweeper Systems Incorporated
• Inventors: Wilkerson, Kenneth R., Thomack, Donald W.
• Primary Examiner(s): Bushey, Charles S.
• Application Number:
  US08/150,698
• Time in Patent Office: 531 Days
• Field of Search: 15/340.1, 15/352, 15/353, 55/302, 55/320, 55/321, 55/323, 55/324, 55/325, 55/337, 55/356, 55/447, 55/498
• US Class Current: 55/302
• CPC Class Codes: B01D 2279/55 for cleaning appliances, e.g. suction cleaners suction cleaners comprising filters A47L9/10
• CPC Class Codes: B01D 46/2411 Filter cartridges
• CPC Class Codes: B01D 46/4281 Venturi's or systems showing a venturi effect
• CPC Class Codes: B01D 46/521 using folded, pleated material
• CPC Class Codes: B01D 46/71 with pressurised gas, e.g. pulsed air
• CPC Class Codes: E01H 1/0827 Dislodging by suction; Mechanical dislodging-cleaning apparatus with independent or dependent exhaust, e.g. dislodging-sweeping machines with independent suction nozzles combined with blowing E01H1/0872; Mechanical loosening devices working under vacuum
• CPC Class Codes: Y02A 50/2351 Atmospheric particulate matter [PM], e.g. carbon smoke microparticles, smog, aerosol particles, dust

Abstract

An air filtration system for use in capturing fugitive dust in industrial sweeping operations includes a hopper having internal structure for causing change in the direction of flow of suction air which enters the hopper along with debris collected during an industrial sweeping operation. A plurality of filters is disposed within the hopper for filtering the suction air, each one of the plurality of filters having filter media therein which can be repeatedly purged for cleaning and continuous reuse thereof. Structure is included for providing repeated purging blasts of air to the plurality of filters, and structure is associated with each one of the plurality of filters for causing the purging blasts of air to clean substantially the entire filter media of each one of the filters. The system also includes structure for creating suction air which is pulled through the hopper and the filters disposed therein before exit of the suction air from the hopper substantially free from debris, particulate matter and fugitive dust which is collected by the system.

Claims

1. An air filtration system for use in capturing fugitive dust in industrial sweeping operations, the system comprising

an enclosed hopper having internal structure for causing change in the direction of flow of suction air which enters the hopper along with debris collected during an industrial sweeping operation,

a plurality of filters disposed within the hopper for filtering the suction air, each one of the plurality of filters having filter media therein which is repeatedly purged for cleaning and continuous reuse thereof,

means for providing repeated purging blasts of air to the plurality of filters,

means associated with each one of the plurality of filters for causing the purging blasts of air to clean substantially the entire filter media of each one of the filters, and

means for creating suction air which is pulled through the hopper and the filters disposed therein before exit of the suction air from the hopper substantially free from debris, particulate matter and fugitive dust which is collected by the system,

wherein the hopper is an enclosed hopper having a right side wall and a left side wall, with respect to the position of an operator of the system, a front wall and a rear wall, a floor and a roof, and wherein the internal structure in the hopper for causing change in direction of the suction air includes an arrangement of walls disposed within the hopper in transverse relationship to a longitudinal axis extending from the front wall to the rear wall, wherein the arrangement of walls included in the internal structure of the hopper for causing change in direction of suction air includes a first wall, a second wall and a third wall disposed in relationship to each other so as to cause the suction air flow to change in direction to such a degree as to, in combination with the effect of gravity, cause large pieces of debris and relatively smaller particulate matter to be removed from the flow of suction air prior to contacting the plurality of filters disposed within the hopper,

wherein the first wall is positioned forwardly of the rear wall of the hopper and extends transversely between and intersects the right side wall and the left side wall of the hopper so as to form a bin within the hopper for collection of large pieces of debris which are taken into the system along with the suction air, the first wall terminating upwardly near, but not intersecting, the roof of the hopper and having positioned between and connecting the upper end of the first wall and the roof of the hopper a screen having mesh of sufficiently small size to prevent large pieces of debris from passing therethrough while being of sufficiently large size to permit passage therethrough with suction air of particulate matter and fine dust which is smaller than the debris collected in the bin,

wherein the rear wall of the hopper includes an inside surface and an outside surface and wherein the first wall of the internal structure of the hopper includes a front surface and a back surface, the back surface facing the inside surface of the rear wall of the hopper on opposed front and back sides of the bin formed therebetween,

and further comprising a first deflection shield and a second deflection shield, the first deflection shield being connected to the inside surface of the rear wall of the hopper and the second deflection shield being connected to the back surface of the first wall, the first deflection shield and the second deflection shield being spacedly positioned on the rear wall and the first wall, respectively, so as to open concavely toward each other, and being positioned relative to the flow of suction air which flows into the bin so as to cause the formation of an air vortex within the bin.

2. The system of claim 1, wherein the second wall is disposed parallel to and spacedly forward of the first wall so as to form a vertical passage therebetween, the second wall terminating spacedly upwardly from the floor of the hopper so that suctioned air first passes downwardly in front of the first wall, then passes beneath a lowermost end of the second wall and then passes upwardly in front of the second wall, to thereby cause particulate matter which is of such size as to pass through the screen connected at the top of the first wall to be deposited upon the floor of the hopper beneath the lowermost end of the second wall, forwardly of a lowermost end of the first wall, the lowermost end of the first wall including a hinged door which pivotally opens toward the bin formed between the first wall and the rear wall of the hopper when the hopper is selectively tilted upwardly and rearwardly to facilitate removal of collected debris and particulate matter therefrom.

3. The system of claim 2, and further comprising a first subceiling and a second subceiling disposed parallel and spaced apart in relation to one another and parallel to and spacedly beneath the roof of the hopper so as to form a first plenum and a second plenum parallel to one another beneath the roof of the hopper, the first subceiling being positioned beneath the second subceiling and providing a mounting site for the plurality of filters, the first plenum being formed above the first subceiling, and further wherein the third wall is disposed forwardly of the second wall transversely between and intersecting the right and left side walls of the hopper, the third wall extending from the floor of the hopper upwardly to and intersecting with the first subceiling to which the plurality of filters are mounted so as to form a chamber beneath the plurality of filters, the chamber being in air flow communication with the first plenum through the plurality of filters and the first plenum being in communication with the means for causing suction air, to thereby cause the suction air to be pulled over the first wall, then under the second wall and then upwardly through the plurality of filters, then through the first plenum, and through means for causing suction air before exiting the air filtration system.

4. The system of claim 1, wherein the plurality of filters are filters of the drum type suspended within the hopper and the filter media thereof is of the pleated paper type.

5. The system of claim 4, wherein each of the plurality of drum-type filters has a 12 inch exterior diameter and the pleated paper filter media of each of the plurality of filters is formed into from 80 to 160 pleats spacially evenly arranged around the perimeter of the corresponding filter.

6. The system of claim 5, wherein the plurality of filters comprises 12 filters arranged in three rows of four filters, each filter being radially spaced apart from every adjacent filter by a distance of at least six inches.

7. An air filtration system for use in capturing fugitive dust in industrial sweeping operations, the system comprising

an enclosed hopper having internal structure for causing change in the direction of flow of suction air which enters the hopper along with debris collected during an industrial sweeping operation,

a plurality of filters disposed within the hopper for filtering the suction air, each one of the plurality of filters having filter media therein which is repeatedly purged for cleaning and continuous reuse thereof,

means for providing repeated purging blasts of air to the plurality of filters,

means associated with each one of the plurality of filters for causing the purging blasts of air to clean substantially the entire filter media of each one of the filters, and

means for creating suction air which is pulled through the hopper and the filters disposed therein before exit of the suction air from the hopper substantially free from debris, particulate matter and fugitive dust which is collected by the system, wherein the hopper is an enclosed hopper having a right side wall and a left side wall, with respect to the position of an operator of the system, a front wall and a rear wall, a floor and a roof, and wherein the internal structure in the hopper for causing change in direction of the suction air includes an arrangement of walls disposed within the hopper in transverse relationship to a longitudinal axis extending from the front wall to the reaf wall, wherein the arrangement of walls included in the internal structure of the hopper for causing change in direction of suction air includes a first wall, a second wall and a third wall disposed in relationship to each other so as to cause the suction air flow to change in direction to such a degree as to, in combination with the effect of gravity, cause large pieces of debris and relatively smaller particulate matter to be removed from the flow of suction air prior to contacting the plurality of filters disposed within the hopper, wherein the first wall is positioned forwardly of the rear wall of the hopper and extends transversely between and intersects the right side wall and the left side wall of the hopper so as to form a bin within the hopper for collection of large pieces of debris which are taken into the system along with the suction air, the first wall terminating upwardly near, but not intersecting, the roof of the hopper and having positioned between and connecting the upper end of the first wall and the roof of the hopper a screen having mesh of sufficiently small size to prevent large pieces of debris from passing therethrough while being of sufficiently large size to permit passage therethrough with suction air of particulate matter and fine dust which is smaller than the debris collected in the bin, wherein the second wall is disposed parallel to and spacedly forward of the first wall so as to form a vertical passage therebetween, the second wall terminating spacedly upwardly from the floor of the hopper so that suction air first passes downwardly in front of the first wall, then passes beneath a lowermost end of the second wall and then passes upwardly in front of the second wall, to thereby cause particulate matter which is of such size as to pass through the screen connected at the top of the first wall to be deposited upon the floor of the hopper beneath the lowermost end of the second wall, forwardly of a lowermost end of the first wall, the lowermost end of the first wall including a hinged door which pivotally opens toward the bin formed between the first wall and the rear wall of the hopper when the hopper is selectively tilted upwardly and rearwardly to facilitate removal of collected debris and particulate matter therefrom, and further comprising a first subceiling and a second subceiling disposed parallel and spaced apart in relation to one another and parallel to and spacedly beneath the roof of the hopper so as to form a first plenum and a second plenum parallel to one another beneath the roof of the hopper, the first subceiling being positioned beneath the second subceiling and providing a mounting site for the plurality of filters, the first plenum being formed above the first subceiling, and further wherein the third wall is disposed forwardly of the second wall transversely between and intersecting the right and left side walls of the hopper, the third wall extending from the floor of the hopper upwardly to and intersecting with the first subceiling to which the plurality of filters are mounted so as to form a chamber beneath the plurality of filters, the chamber being in air flow communication with the first plenum through the plurality of filters and the first plenum being in communication with the means for causing suctioned air, to thereby cause the suction air to be pulled over the first wall, then under the second wall and then upwardly through the plurality of filters, then through the first plenum, and through means for causing suction air before exiting the air filtration system, wherein the means for purging of the plurality of filters includes a source of high pressure air and a plurality of air nozzles connected to the source of high pressure air and connected to the second subceiling, one of the plurality of air nozzles being positioned above, and directed toward, a corresponding one of the plurality of filters, and a plurality of Venturi tubes, one Venturi tube disposed longitudinally and coaxially above a corresponding one of the plurality of filters beneath a corresponding air nozzle, for receiving a blast of high pressure air from the air nozzle and enhancing the volume of the blast of air and directing the air into the filter, and a plurality of air flow diffusers, one of the plurality of air flow diffusers disposed coaxially and longitudinally beneath each Venturi tube within a corresponding one of the plurality of filters to thereby soften the air blast and divert a portion of the purging air flow toward an upper portion of an inside of the filter, as well as permitting a portion of the purging blast of air to travel to a bottom of the corresponding filters.

8. The system of claim 7, and further comprising means for purging each one of the plurality of filters with a blast of air which lasts for one half second out of every 20 seconds of system operation and which causes the suction air flow to operate on all of the plurality of filters continually.

9. The system of claim 7, and further comprising means for providing each filter purging blast of air at approximately 78 cfm and for enhancing each blast by the corresponding Venturi tube to overcome the force of the suction air, and still further comprising means for providing the suction air of the system at approximately 14,000 to 16,000 cfm.

10. The system of claim 7, wherein the filtering means is a plurality of filters of the drum-type suspended within the hopper and the filter media thereof is of the pleated paper-type.

11. The system of claim 10, wherein each of the plurality of drum-type filters has a 12 inch exterior diameter and the pleated paper filter media of each of the plurality of filters is formed into from 80 to 160 pleats spacially evenly arranged around the perimeter of the corresponding filter.

12. The system of claim 11, wherein the first subceiling is provided with a plurality of apertures spaced apart from one another and arranged so that one of the plurality of apertures is disposed coaxially and beneath a corresponding air nozzle, and a plurality of spider rings, one of the plurality of spider rings being connected to the subceiling coaxially in relation to a corresponding one of the plurality of apertures in the first subceiling to thereby provide a mounting site from which each of the drum-type filters which are mounted to the first subceiling are suspended.