Patent Publication Number: US-3880624-A

Title: Apparatus for washing gases and removing liquid entrained

Description:
United States Patent Arnold et al.  
 14 1 Apr. 29, 1975 2/1908 Kincaly 55/440 960.374 6/1910 Muchka 55/440 2.358.508 9/1944 Hersh r 55/494 2.608.267 8/1952 55/235 3.254.475 6/1966 55/440 3.646.728 3/1972 55/233 3.748.835 7/1973 55/228 3.767.177 10/1973 Engalitchcff et al 55/25 Primary E.\aminerBernard Nozick Attorney. Agent. or FirmRobert H. Bachman [5 7] ABSTRACT Apparatus for cleaning gases, especially the dust laden air adjacent a coal transfer means and other particulate laden gases or air. including a gas washing zone. means for supplying a liquid spray to the gases in the washing zone and a gas drying zone for removing the entrained liquid droplets from the gases.  
 24 Claims, 5 Drawing Figures APPARATUS FOR WASHING GASES AND REMOVING LIQUID ENTRAINED BACKGROUND OF THE INVENTION It is highly desirable to develop efficient and compact devices for cleaning gases. It is particularly desirable to develop such devices which are suitable for cleaning the air and dust adjacent a coal transfer apparatus in view of the large amount of dust which is generated by such an apparatus. It is also desirable to develop such an apparatus which is versatile so that it may readily be used for the removal of other air or gas borne particulate ranging in sizes from macro to submicron dimensions originating from any of a variety of sources.  
  Accordingly, it is a principal object of the present invention to provide an efficient. compact and versatile device for cleaning gases, such as the dust which is generated adjacent a coal transfer apparatus. as by grind ing. handling. processing, etc.  
  It is additional object of the present invention to provide such an apparatus which may be made portable and is utilizable in a location where a limited amount of space is available, such as in a mine tunnel adjacent acoal transfer means. A further object is to provide such a device which has the necessary high capacity for removing large amounts of dust and particulate from the air. An additional object of the present invention is to develop an apparatus as aforesaid which is versatile so that it may be used generally in cleaning particulate laden gases or air.  
  Further objects and advantages of the present invention will appear from the ensuing specification.  
 SUMMARY OF THE INVENTION In accordance with the present invention the foregoing objects and advantages are readily achieved and a device provided for cleaning gases especially suitable for cleaning the dust from the air adjacent a coal transfer device. although the present invention is well suited generally for cleaning particulate laden gases or air and for removal of particulate from other emission generating devices or processes. The apparatus of the present invention comprises an inlet for introducing the gases to be cleaned. a gas washing zone communicating with the inlet including means supplying a liquid spray to the gases. a gas drying zone communicating with the gas washing zone for removing entrained liquid droplets from said gases. a gas outlet communicating with said gas drying zone. and a liquid outlet communicating with the drying zone for removing the liquid separated from the gases in the drying zone. whrein the gas drying zone includes a series of fixed. spaced. curved vanes adjacent said gas washing zone. with the trailing edge of said vanes being curved at leat 180 to form a channel for collection of entrained droplets. and with said vanes being arranged adjacent the gas washing zone so that a portion of the water laden gas impinges upon each of said vanes.  
  When the apparatus of the present invention is utilized for cleaning the dust from the air adjacent a coal transfer device or from other particulate generating devices or processes. there is provided a means for confining the gases to be cleaned adjacent the inlet and means for inducing a positive flow of gas into the inlet.  
 BRIEF DESCRIPTION OF THE DRAWINGS The features of the apparatus of the present invention will be more readily apparent to one skilled in the art from reading the following detailed description of a representative embodiment of the present invention when considered in the light of the accompanying drawings in which:  
  FIG. I is a sectional view of a coal transfer device in a mine including the cleaning apparatus of the present invention;  
  FIG. 2 is a horizontal sectional view of the cleaning apparatus of the present invention taken on line 2-2 of FIG. 1;  
  FIG. 3 is a vertical sectional view of the cleaning apparatus of the present invention taken on line 33 of FIG. 2&#39;.  
  FIG. 4 is a sectional view of a modified apparatus of the present invention taken on line 4-4 of FIG. 5; and  
  FIG. 5 is an end view of the outlet end of the modified apparatus of FIG. 4.  
 DETAILED DESCRIPTION FIG. 1 shows a conventional coal transfer device 10 in a mine tunnel having a roof 11 and a floow 12. The coal transfer device includes a series of high speed endless belts. such as belt 13a and 13b. The leading end of belt 13b is beneath the trailing end of belt 13a so that the coal 14 carried on belt 13a falls from belt 13a to belt 13b and continues on belt 13b. The coal travels at very high speeds and generates a great deal of coal dust especially adjacent the trailing end of belt 13a and the leading end of belt 13b. The mine tunnel represents a particularly difficult problem in view of the limited amount of space available. the tunnel being narrow and having a low ceiling. and the very large amount of dust generated. Thus. one requires a high capacity. compact and highly efficient gas cleaning apparatus which is capable of operating in a horizontal plane in a narrow and low ceiling tunnel.  
  The gas cleaning apparatus of the present invention 20 includes an inlet 21 above the trailing end of belt for introducing the gases to be cleaned. a gas washing zone 22 communicating with the inlet. a gas drying zone 23 communicating with the washing zone and a gas outlet 24 communicating with the gas drying zone for removing the cleaned gases. Means is provided adjacent the gas outlet 24, such as fan 25. for inducing a positive flow of gas into the inlet 21. An enclosure or housing 26 is provided adjacent inlet 21 for confining the gases to be cleaned adjacent said inlet. including upper wall 26a located above inlet 21 and above the trailing end of belt 13a. having a descending wall 26b. and including lower wall 260 located below the leading end of belt 1312. having ascending walls 26d on opposite ends of lower wall 260.  
  The cleaned gas is caused to flow through outlet 24 by means of fan 25, through upper and lower exhaust channels 27 and 28, respectively. passing respectively above and below apparatus 20 and having their exhaust outlets 27a and 28a adjacent inlet 21, all in the direction of the arrows. Thus a positive flow of air is induced through the apparatus of the present invention. with the air flow being in the major direction of the air flow in the tunnel. Even if, however. back drafts cause an oppositely directed air flow in the tunnel. the apparatus 20 of the present invention is a tight enclosure which is able to operate efficiently combined with fan 25 and enclosure 26. Alternatively, one might provide an air escape means adjacent outlet 24 to allow all or part of the cleaned air to be discharged in the tunnel and further aid in improving the air quality in the tunnel. As a further alternative, one might place the fan 25 adjacent the inlet 21, or inside the apparatus 20, or use two or more smaller capacity fans in different locations. Exhausting of air from the unit may be in a recycled or push-pull air system as described in FIG. 4, or so that the exhausted air is put into a disperser in the space such as in a tunnel or room for distributing and directing the clean air in the proper direction.  
  Referring to FIG. 2, the dirty gas is introduced into inlet 21 and into the gas washing zone 22 communicating with the inlet. The gas washing zone is intended to provide a curtain of water of high kinetic energy to thoroughly wet the incoming gas stream and by inpact with the airborne particles captures them so that the dust particles contained in the gas stream as thoroughly enveloped by the liquid droplets and removed from the airflow pattern. A powerful, high kinetic energy spray means should be employed in the washing zone to serve this purpose which provides a uniform distribution across the path of the airflow, such as that described in copending application Ser. No. 3l8,692 by Orlan M. Arnold and Carlo A Vancini, filed Dec. 26,1972.  
  A particularly suitable arrangement is shown in FIG. 2 and includes a spray nozzle 30, mounted on a supply pipe 31, disposed axially of the washing zone 22 and carrying a disc 32 having a curved under surface by which the jet of liquid from the nozzle 30 is deflected radially outwardly to form a radial spray of high kinetic energy around its entire periphery. The nozzle 30 is disposed in alignment with curved, annular recess 33 located in the wall of the washing zone 22 so that the outwardly directed spray is reversed in direction by curved surface 33 with a minimum loss of kinetic energy to pass inwardly through the gas stream in the washing zone 22. Naturally, if desired, a plurality of nozzles may be utilized in the washing zone, or a plurality of washing zones.  
  The gas containing entrained liquid droplets passes from the washing zone 22 to the drying zone 33. The drying zone 23 includes a primary drying zone 23a and a secondary drying zone 23b. The water laden dirty air passes into the primary drying zone 23a and is divided into fractions by a series of fixed, spaced, curved vanes 40 arranged adjacent the gas washing zone so that a controlled portion of the water laden gas impinges upon each of the vanes and liquid droplets are separated therefrom, with the controlled impingement being such as to provide a metered distribution of the bulk air from the wash chamber onto the vanes. The forward portion 41 of each vane is curved towards the washing zone and the trailing portion 42 of each vane is curved at least 180 and perferably at least 240 to form a channel for collection of entrained droplets. Three sets of vanes are shown, a first set of vanes 40a and 40b closest to the washing zone, a second intermediate set of vanes 40c and 40d, and a third set of vanes 40e and 40f farthest from the washing zone. Each vane has an oppositely directed vane, with their respective curved forward portions 41 spaced apart a predetermined distance. Thus, the first set of vanes 40:: and 4012 have their respective curved forward portions 41 spaced farthest apart, and the second set of vanes 40(- and 4041 have their respective curved forward portions 41 spaced relatively closer together than the first set. and the third set of vanes 40c and 40fhave their respective curved forward portions contacting each other so that all of the water laden dirty air is caused to contact one of the vanes 40 and that said air is divided into relatively equal fractions for water elimination. Optionally a fourth set of curved vanes 40g and 4011 is provided adjacent the wall of the gas drying zone to catch water laden air which may be thrown towards the wall. Naturally, more than three sets of vanes may be provided in the primary drying zone 23a. Also, the configuration of the vanes may be varied to, for example. provide a sharp, right angle curve on forward portions 41 instead of the gradual curved surfaces shown. The primary dyring zone 23a is particularly important as it provides the zone for separation of the dirty slurry. The separated slurry flows down channels 42 into drainage trough or passages 43 (see FIG. 3) beneath each channel and communicating with a liquid outlet 44. If desired, passages 43 may be eliminated and the floor 45 of the cleaning apparatus by gradually sloped towards liquid outlet 44. Washing troughs 46 fed by inlet 47 may be provided above each of the channels 42 for washing channels 42 via spray nozzles 48. Troughs 43 are cleaned by pipe 47a.  
  Directly behind the primary drying zone 23a is the secondary drying zone 23b. If desired, one may dispense with the secondary drying zone and utilize only the primary zone; however, the embodiment described is preferred for maximum efficiency in a high capacity, high efficiency, compact unit.  
  The secondary drying zone 2312 includes two sets of fixed, spaced, curved parallel moisture eliminators or vanes 50 and 51 between outlet 24 and the primary drying zone 23a, support means 52 and 53 supporting vanes 50 as a unit, and support means 54 and 55 supporting vanes 51 as a unit. Each set 50 and 51 includes a plurality of curved individual vanes 51a forming a tortuous path for introducing turbulence and for providing impingement surfaces for droplet separation. The individual vanes are desirably provided in segment sections, with the ability to remove them as well as to lock them into position. If desired, sectional segments may each carry a plurality of vanes. The sections may be removed as well as locked in place, as by plate 56 and bolt 57. The trailing end of each of said vanes is curved at least and preferably at least 240 to form a channel 58 for liquid drainage, with trough or drainage passageway 43 being located beneath each channel 58, said through 43 being an extension of the trough beneath channels 42 in the primary drying zone 23a. The tortuous path formed by vanes 51a and the channels 58 also serves to prevent the airflow whipping through vanes 50 and 51 with incomplete water separation resulting. The vanes in both the primary and secondary drying zones extend the entire height of the cleaning apparatus to insure efficient operation.  
  As shown in FIG. 2, set 50 is spaced from set 51 to form a V-shaped assembly with the base of the V being adjacent the primary drying zone and wide portion of the V being adjacent the outlet 24 so that a portion of the gas passing from the primary zone 23a into the secondary zone 23b impinge upon each of said vanes 51a and different volumes of air are readily accommodated both in the inlet to zone 23b and in the outlet of zone 23b. Therefore, the assembly of moisture eliminators 50 and 51 is at an acute angle with respect to the entering gases and the individual vanes 51a may be spaced apart approximately uniformly as shown. Alternatively.  
 the angle may be varied and the spacing varied to compensate therefor. Also, other arrangements may be employed, such as a single set placed across the secondary drying zone. In addition, different types of drying units may be employed, such as baffle trays with slots and centrifugal separators or deflector plates of known construction, as shown in more detail in copending application Ser. No. 306,6l l, for Apparatus For Cleaning Gases by O. M. Arnold et al.  
  The secondary water supply fed by inlet pipes 47 represents a particular advantage as it passes over channels 42 and 58 for cleaning thereof. The water supply may be arranged to be manually or automatically operated, could be placed on an automatic cycle, and could be adapted to use fresh or recycled water.  
  The cleaned and dried air passes out gas outlet 24 as previously described. Referring again to FIG. 1, the separated liquid flows out liquid drain 44 via line 60 into tank 61. Valve 62 is provided on line 60 so that the liquid flow may be diverted to lilne 63 carrying valve 64 for drainage into a pond or a cleaning tank spaced a distance from the cleaning apparatus, or alternatively the liquid flow from line 63 may be dispersed on the coal belt 1312 with controlled or intermittent flow depending if coal is present on the belt. Valve 65 is provided on line 60 adjacent holding tank 61 so that all or a portion of the liquid may be diverted to line 66 carrying valve 67 from whence it is pumped to lines 68 and 69 via pump 70 for providing a spray 69a on coal 14 being carrying by belt 13b. Valve 71 is provided on line 69 for controlling the liquid flow to the coal. Although only one pump is shown in FIG. 1, it is preferred that a separate line and pump be used for this purpose since V the liquid being carried thereby is a dirty slurry which may require a special pump, thereby enabling the use of a high pressure pump for supplying water to washing zone 22. Also, if desiredpan air suction pump may be provided adjacent liquid outlet 44 to aid in drawing the liquid down to the bottom of the cleaning apparatus and in the removal of the dirty water from the cleaning apparatus. Normally, however. sufficient suction will be provided by fan 25 adjacent outlet 24 to obviate the necessity of such an air suction pump. As indicated hereinabove, one may place fan 25 adjacent inlet 21, or inside apparatus 20, or use two or more smaller fans in different locations. When fan 25 is placed after the drying zone as shown in FIG. I, if the full suction is generated in the drying zone there may not be appreciable suction available to help remove the liquid from the cleaning apparatus. One may place an obstruction of suitable size at exit 24 so that there is a differential air pressure at that point. and one might require a higher horsepower fan. Alternatively, where the fan is placed between the two drying chambers, a baffled passageway may be employed in order to generate sufficient suction to remove the liquid. it should be emphasized that the liquid flow should be shut off if the fan is shut off or stopped for any reason.  
  Tank 61 may be provided with a water make up line 72 with a float valve 73 in the tank to maintain the liquid in the tank at a desired level. Naturally. wetting agents or the like may be added to tank 61 via make up line 72, for example, it may be desirable to have a rea gent such as a surfactant to be functional in the recy cled liquid in the wash chamber and also in the moisture eliminator to assist drainage. Also. means may be provided in tank 61 to clean the dirt from the water returned to the tank and separate the dirt therefrom in a known manner.  
  Pump is provided to pump liquid via lines 68 and 74 to the washing zone 22, with line 74 being provided with valve 75 to control liquid flow therein. Line 76 carrying valve 77 is also connected to line 68 for providing wash liquid to lines 47. Naturally, as indicated hereinabove, separate pumps and lines may be provided for each of these functions. Also, if desired, a filter may be provided on line 74 and/or 76 to insure that clean water is fed by these lines. This is especially desirable if a single pump is used.  
  Access doors 80 are provided on the cleaning apparatus 20 to enable ease of cleaning and repair.  
  The modification of FIG. 4, wherein like numbers show like parts, shows a large water compartment beneath the vanes 40 in order to provide sufficient liquid to utilize in a closed system with the need for limited water make up. Thus, the liquid is transferred to line 91 via pump 92 to line 93 from whence it is directed via valves 94 and 95 and 96 to either channel cleaning line 97 or nozzle supply line 98. Make-up line 99 is provided if necessary. Compartment 90 is pro vided with a sump 90a adjacent the outlet end of the apparatus for collection of water for recycling. Fan 100 is provided adjacent exhaust line 101. Air channel 102 is provided around exhaust line 24 with tilt floor 103 so that when the floor 103 is in the open position shown in solid line in FIG. 4 a positive airflow is caused through channel 102 aiding in water drainage towards pump 92. When the floor is in the position shown in the dashed lines, channel 102 is blocked and water drainage via exhaust line 101 is caused.  
  This invention may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims. and all changes which come within the meaning and range of equivalency are intended to be embraced therein.  
 What is claimed is:  
  1. Apparatus for cleaning gases comprising: an air inlet for introducing the gases to be cleaned; a gas washing zone communicating with said inlet including means supplying a liquid spray to said gases; a gas drying zone communicating with said gas washing zone for removing entrained liquid droplets from said gases; a gas outlet communicating with said gas drying zone for removing the cleaned gases; and a liquid outlet communicating with said drying zone for removing the liquid separated from said gases in the drying zone; wherein said gas drying zone includes a series of spaced. curved vanes fixed in said drying zone adjacent said gas washing zone, said vanes being arranged adjacent the gas washing zone so that a controlled portion of the water laden gas impinges upon each of said vanes to provide a metered distribution of water laden gas into individual vanes, with said vanes having a curved trailing edge forming a channel for collection of liquid droplets and a forward portion curved towards said gas washing zone, wherein each vane has an oppositely directed vane to form a set with their respective curved forward portions spaced apart a predetermined distance. with respective forward portions of the set farthest from the gas washing zone being spaced closest together and the respective forward portions of succeeding sets towards the gas washing zone being spaced farther apart.  
  2. Apparatus according to claim I wherein the trailing edge of said vanes are curved to least 180.  
  3. Apparatus according to claim 1 including three set of vanes with the third set being farthest from the gas washing zone and having their forward portions contacting each other and with the second set having their forward portions closer together than the first set.  
  4. Apparatus according to claim 1 including washing means above each of said channels for washing said channels.  
  5. Apparatus according to claim 1 including a second series of spaced, curved, parallel vanes fixed in said gas drying zone between said gas outlet and said first series of vanes, means supporting said second series as a unit, with the trailing edge of said vanes being curved at least 180 to form a channel for collection of entrained droplets.  
  6. Apparatus according to claim 5 wherein said second series forms a tortuous path for inducing controlled turbulence and causing the entrained droplets to impinge on the surfaces of the vanes.  
  7. Apparatus according to claim 5 wherein the individual vanes in said second series comprise removable sectional segments.  
  8. Apparatus according to claim 5 wherein said second series of vanes includes two sets, with each set being supported as a unit and with the first set being spaced from the second set to form a V-shaped assembly so that a portion of the gas impinges upon each of said vanes.  
  9. Apparatus according to claim 5 including means above each of said channels in the second series for washing said channels.  
  10. Apparatus according to claim 9 including a liquid drainage channel beneath each of said channels communicating with said liquid outlet.  
  ll. Apparatus according to claim 1 including means for inducing a positive flow through said apparatus.  
  12. Apparatus according to claim 11 wherein said means for inducing a positive flow is a fan located adjacent said gas outlet.  
  13. Apparatus according to claim 12 including a fan adjacent said liquid outlet to aid in removing liquid from said apparatus by extracting a small portion of gas together with the liquid.  
  14. Apparatus for cleaning the air adjacent a coal transfer means comprising an inlet for introducing the gases to be cleaned, means for confining the gases to be cleaned adjacent said inlet, means for inducing a positive flow of gas into said inlet. a gas washing zone communicating with said inlet including means supplying a liquid spray to said gases. a gas drying zone communicating with said gas washing zone for removing entrained liquid droplets liquid droplets from said gases, wherein said gas drying zone includes a series of spaced, curved vanes fixed therein adjacent said gas washing zone, with said vanes being arranged adjacent the gas washing zone so that a portion of the water laden gas impinges upon each of said vanes, said vanes having a curved trailing edge forming a channel for collection of liquid droplets and a forward portion curved towards said gas washing zone, wherein each vane has an oppositely directed vane to form a set with their respective curved forward portions spaced apart a predetermined distance, with respective forward portions fof the set farthest from the gas washing zone being spaced closest together and the respective forward portions of succeeding sets towards the gas washing zone being spaced farther apart, a gas outlet communicating with said drying zone, and a liquid outlet communicating with siad drying zone for removing the liquid separated from said gases in the drying zone.  
  15. Apparatus according to claim 14 including means to spray the coal with the liquid separated from the gases.  
  16. Apparatus according to claim 14 including means to recycle the liquid separated from the gases to the liquid spray in said washing zone.  
  17. Apparatus according to claim 14 wherein the trailing edge of said vanes are curved at least 180.  
  18. Apparatus according to claim 14 wherein a controlled portion of the water laden gas impinges upon each of said vanes to provide a metered distribution of water ladaen gas onto individual vanes.  
  19. Apparatus according to claim 14 including a first endless belt for transferring the coal having a leading and trailing end. and a second endless belt for transfering the coal having a leading and trailing end. wherein the leading end of the second belt is beneath the trailing end of the first belt so that the coal falls from the first to the second belt. wherein said means confining the gases is adjacent the trailing edge of the first belt.  
  20. Apparatus according to claim 14 including three sets of vanes with the third set being farthest from the gas washing zone and having their forward portions contacting each other and with the second set having their forward portions closer together than the first set.  
  21. Apparatus according to claim 14 including washing means above each of said channels for washing said channels.  
  22. Apparatus according to claim 14 including a second series of fixed, spaced, curved, parallel vanes between said gas outlet and said first series of vanes, means supporting said second series as a unit, with the trailing edge of said vanes being curved at least l to form a channel for collection of entrained droplets.  
  23. Apparatus according to claim 22 wherein said second series forms a tortuous path for inducing turbulence and causing the entrained droplets to impinge on the surfaces of the vanes.  
  24. Apparatus according to claim 22 wherein said second series of vanes includes two sets, with each set being supported as a unit and with the first set being spaced from the second set to form a V-shaped assembly so that a portion of the gas impinges upon each of