US3225525A

US3225525A - Cyclone dust collector having a wear shield

Info

Publication number: US3225525A
Application number: US229415A
Authority: US
Inventors: William E Archer
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1962-10-09
Filing date: 1962-10-09
Publication date: 1965-12-28
Anticipated expiration: 1982-12-28

Description

Dec. 28, 1965 w. E. ARCHER CYCLONE DUST COLLECTOR HAVING A WEAR SHIELD Filed Oct. 9. 1962 )S IO W 14 PR/m 4/er HG]. Hem ARI INVENTORZ WILLIAM E. ARCHER ATTORNEY United States Patent C) 3,225,525 CYCLONE DUST CQLLECTOR HAVING A WEAR SELD William E. Archer, Portuguese Bend, Calif., assignor to Joy Manufacturing Company, Pittsburgh, Pin, a corporation of Pennsylvania Filed Oct. 9, 1962, Ser. No. 229,415 6 Claims. (Cl. 55346) This invention relates to a particle collector and more particularly to a Wear shield mounted on a portion of each outlet tube in the firs-t row of outlet tubes in a multi-row, multiple unit cyclone type collector to protect such first row of tubes from the wearing effect of abrasive particles in an incoming stream of gases having abrasive particles entrained therein.

It is common practice in mechanical collectors having outlet tubes, extending into the path of the stream to be cleaned, to protect the leading face of the first row of outlet tubes with a wear shield when abrasive particles are entrained in the stream to be cleaned. It is also known that one factor in determining the wear rate of a surface exposed to a stream of dusty gases having abrasive particles entrained therein is the size of the angle of impingement (the acute angle between the direction of the flow of gases and the surface on which the wear is taking place). An investigation by R. L. Stoker titled, Erosion Due to Dust Particles in a Gas Stream, and published in Industrial and Engineering Chemistry, volume 41, page 1196, June 1949, showed that black iron exposed to a jet of air containing silica-sand had a maximum wear rate at an impingement angle of approximately 20 with relatively high wear rate for all angles between 15 and 55 as compared with the rate of wear at an impingement angle of 90. From this and other studies it is apparent that the desirable angles of impingement would be either very small, in the range from to 15, or very large, in the range of 60 to 90. The wear shield of the present invention provides these desirable impingemen-t angles.

Accordingly, one object of this invention is to provide a new and improved particle collector having a wear shield mounted on a portion of an outlet tube to protect such tube from the wearing effect of abrasive dust in an incoming stream of gases having abrasive particles entrained therein.

Another object of this invention is to provide a new and improved wear shield.

It is a further object of this invention to provide a new and improved particle collector having a wear shield mounted on a portion of each outlet tube in a first row of outlet tubes in a multi'row, multiple unit cyclone type dust collector to protect such tubes from wearing effect of abrasive dust in an incoming stream of dusty gases, said wear shield having a surface which yields an impingement angle with the stream of dusty gases greater than 60 on a main portion of such surface and less than 15 on subsidiary portions of such surface.

These and other objects and advantages of this invention will become more apparent upon consideration of the following description and drawings in which:

FIG. 1 is a schematic representation of a multi-row, multiple unit, cyclone type dust collector having wear shields constructed according to the principles of this invention mounted on each tube of the first row of outlet tubes, respectively;

FIG. 2 is a sectional view taken substantially along the line 22 of FIG. 1;

FIG. 3 is a sectional view taken along line 33 of FIG. 1;

FIG. 4 is a sectional view similar to FIG. 3 showing a 3,225,525 Patented Dec. 28, 1965 "ice second embodiment of the wear shield of this invention;

FIG. 5 is a sectional view similar to FIG. 3 showing a third embodiment of the wear shield of this invention;

FIG. 6 is a sectional view similar to FIG. 3 of a Wear shield of the prior art; and

FIG. 7 is a sectional View of a second wear shield of the prior art.

In FIG. 1 there is shown a multi-row, multiple unit, cyclone type dust collector of a type Well known in the art generally indicated at 10 and comprising a formed closed housing 11 having an upper portion 15 mounted on a downwardly tapering lower portion or hopper 21. The upper portion 15 communicates with an inlet duct 12 connected to a source of dusty gases (not shown) and also communicates with an outlet duct 14 connected to a chimney or other disposal means (not shown) the upper portion 15 of the housing 11 is divided into an outlet chamber 17 and an inlet chamber 18 by a slanting divider plate 16 extending completely across the upper portion 15, internally. The upper portion 15 is divided from the hopper 21 by a horizontal header plate 19 having a plurality of bores each of which communicates, and is in register, with a cyclone separator 20 of a type well known in the art arranged in a plurality of rows transverse to a stream of gases entering through the inlet duct 12 into the inlet chamber 18. Each separator 20 is provided with an outlet tube 22 extending upwardly through the header plate 19 and the divider plate 16 to communicate with the outlet chamber 17 and the outlet duct 14.

The outlet tubes in the first row of tubes nearest the inlet duct 12 are indicated as tubes 22 and differ from the tubes 22 in that each is provided with an elongated, channel shaped, wear shield 24 rigidly secured to the outer surface of the tube 22' as by welding and having a base portion 25 longitudinally parallel to the axis of the tube 22' and transversely normal to the direction of gas flow from the duct 12 as hereinafter described. The longitudinal centerline of the base portion 25 and the axis of the tube 22' lie in a common plane parallel to the direction of gas flow. The wear shield 24 also has leg portions 26 normal to the base portion 25 and contacting the outer periphery of the tube 22' along circumferentially spaced lines parallel to the axis of the tube 22. The wear shield extends longitudinally along the tube 22 from the divider plate 16 to a point upwardly spaced from the header plate 19 by an amount sufiicient to allow unimpeded gas flow into the cyclone separator 20 of which the respective outlet tube 22' is a part.

It is to be noted that in the preferred embodiment as shown in FIG. 3 the width of the base portion 25 is equal to approximately /6 the diameter of the tube 22'. This ratio is preferred as it is large enough to adequately protect the tube and uses a minimum of material for such protection. Wear shields having this ratio of width to diameter also provide better gas flow than those having a higher ratio since less area of flat surface is opposed to the gas flow. It is further to be noted that the leg portions 26 shown normal to the base portion 25 can be oblique to the base portion 25 spreading to a maximum width equal to the diameter of the tube 22.

In operation of this device a stream of gases having finely divided, solid particulate matter entrained therein enters the chamber 18 of the dust collector 10 from the inlet duct 12 travelling in the direction indicated by an arrowed line 28 in FIG. 3. The entrained particles impinge upon the wear shield at an impingement angle of approximately as indicated by the are 29, with relation to the base portion 25 of wear shield 24. It will be obvious that the impingement angle of the entrained particles with relation to the leg portions 26 will be ap proximately and that angles of impingement between the entrained particles and any portion of the tube 22' exposed to the direct action of the stream of gas will be in the range between the 0 and 15 Since all of the impingement angles of the entrained particles with respect to the wear shield 24 and tube 22' constructed according to the principles of this invention are either approximately 90 or less than 15 optimum conditions for the reduction of the rate of wear are present and the tube and wear shield of this invention will have a much greater useful life than those of the prior art.

Such a prior art device is shown in FIG. 6 wherein an outlet tube 32 is provided with an angle type wear shield 33 having leg portions 34 normal to each other. An arrowed line 35 illustrates the direction of gas flow while an are 36 indicates the size of the impingement angle of particulate matter, entrained in the gas, against the leg portion 34 of the wear shield 33. It is to be noted that the impingement angle 36 is approximately 45 and according to the above cited report is within the range of angle wherein relatively rapid wear takes place as compared with angles greater than 55 or less than 15 and it is obvious that the device of FIG. 6 would have substantially shorter useful life than that of FIG. 3.

In FIG. 4 there is shown a second embodiment 24 of the wear shield of this invention in which the leg portions 26 of the channel are provided with L-shaped extensions 40 having a base portion extending outwardly at right angles to the leg portion 26 and leg portions extending forwardly in the direction of the gas flow, as shown by an arrowed line 38, until such leg portions contact the tube 22 upon which the wear shield 24' is rigidly secured in the same manner as was the wear shield 24. For the wear shield 24 the width of the base portion 25' and of the L-shaped extensions 40 is determined by the diameter of the tube 22'. The base portion 25' having a width equal to approximately /3 of the diameter of the tube and extensions 40 each having a width of of the tube diameter. This results in a total Width of the wear shield equal to /6 of the diameter of the tube. The flat surface area opposed to the gas flow is broken up into portions spaced longitudinally of the gas flow thereby having less resistance to such flow, as is known. Inspection of the FIG. 4 drawing shows that the impingement angle as indicated by an are 39 will be the same for the embodiment of FIG. 4 as for that of FIG. 3 with the attendant advantage of low rate of wear and extended useful life.

FIG. 5 shows a third embodiment of the principles of this invention in an elongated wear shield 42 having an arcuate cross section with a concavo-convex base portion, the inner surface of which is mated to the outer surface of the outlet tube 22' and having along its longitudinal edges radially outwardly extending portions 43. Preferably the greatest transverse dimension across portions 43 is equal to the diameter of the tube 22. With the direction of the gas flow as indicated by an arrowed line 44 the effective impingement angle is that indicated by an are 45 between the arrowed line 44 and a line 46 drawn tangent to the outer surface of the wear shield 42 from the rearmost point of the portion 43. It is to be noted that the angle 45 is approximately 70 which is within the 60 to 90 range cited as being desirable in the above mentioned report. The angle 45 is the effective impingement angle for all portions of the wear shield 42 between the point of tangency of the line 45 with the outer surface of the wear shield 42 and the outwardly extended portion 43. It is obvious that all other impingement angles between the wear shield 42 and the entrained particles in the gas stream travelling in the direction indicated by the arrowed line 44 will be greater than 70 with the consequent reduction rate of wear and extension of useful life hereinbefore cited as advantages residing in the wear shields of this invention.

FIG. 7 shows an arcuate wear shield 48 of the prior art similar to the wear shield 42 of this invention excepting that the outwardly extending portions 43 have been omitted. An arrowed line 50 and an are 51 indicates the direction of gas flow and the impingement angle, respectively, for a portion of the gas stream and entrained particles impinging upon the wear shield 48. It is to be noted that the angle 51 is in the range between 45 and 15 cited in the above mentioned report as yielding high rates of wear common to the. wear shields of the prior art.

Preferred embodiments of this invention having been described and illustrated it is to be realized that modifications thereof can be made without departing from the broad spirit and scope of this invention. It is therefore respectfully requested that this invention be interpreted as broadly as possible and be limited only by the prior art.

What I claim is:

1. In a cyclone collector of the class having multiple rows of collector units, each of said collector units comprising a collector tube coaxial with a cylindrical outlet tube, said rows of collector units being disposed transversely of a stream of gases having abrasive particles entrained therein, said stream of gases entering said cyclone collector through an inlet connection, a first row of said collector units nearest said inlet connection being exposed to wearing effects of said abrasive particles: the improvement comprising the combination of individual elongated wear shields mounted on the upstream sides of said outlet tubes, respectively, of all the collector units in said first row, each of said wear shields having a longitudinal centerline parallel to the axis of said outlet tube coplanar therewith and defining a common plane parallel to a flow path along which said stream of gases flows from said inlet connection to said outlet tube, each said wear shield comprising a base portion normal to said plane and two spaced longitudinally parallel leg portions substantially parallel to said plane and equidistant therefrom and said leg portions extending downstream from the lateral edges of said base portion far enough to make line contact with the external surface of said outlet tube.

2. A cyclone collector as set forth in claim 1 wherein the width of said base portion is equal to approximately /6 of the outside diameter of said outlet tube.

3. In a cyclone collector of the class having multiple rows of collector units, each of said collector units comprising a collector tube coaxial with a cylindrical outlet tube, said rows of collector units being disposed transversely of a stream of gases having abrasive particles entrained therein, said stream of gases entering said cyclone collector through an inlet connection, a first row of said collector units nearest said inlet connection being exposed to wearing effects of said abrasive particles: the improvement comprising the combination of individual elongated wear shields mounted on the upstream sides of said outlet tubes, respectively, of all the collector units in said first row, each of said wear shields having a longitudinal centerline parallel to the axis of said outlet tube coplanar therewith and defining a common plane parallel to a flow path along which said stream of gases flows from said inlet connection to said outlet tube, each said wear shield comprising a base element normal to said plane and two spaced longitudinally parallel leg elements having spaced first and third portions substantially parallel to said plane and respectively equidistant therefrom, said third portions being more remote from said plane than said first portions, said third portions being spaced from and connected to said first portions by second portions parallel to said base element and spaced downstream therefrom, said first portions of said leg elements extending downstream from the lateral edges of said base element and said third portions extending downstream from the lateral edges of said second portions far enough to make linecontact with the external surface of said outlet tube.

4. A cyclone collector as set forth in claim 3 wherein the width of said base element is equal to approximately /5 of the outside diameter of said outlet tube and each of said second portions of said leg elements has a width equal to A of said diameter.

5. A cyclone collector as set forth in claim 3 wherein the width of said base element is equal to approximately /3 of the outside diameter of said outlet tube.

6. In a cyclone collector of the class having multiple rows of collector units, each of said collector units comprising a collector tube coaxial with a cylindrical outlet tube, said rows of collector units being disposed transversely of a stream of gases having abrasive particles entrained therein, said stream of gases entering said cyclone collector through an inlet connection, a first row of said collector units nearest said inlet connection being exposed to Wearing eflects of said abrasive particles: the improvement comprising the combination of individual elongated transversely arcuate Wear shields mounted on the upstream sides of said outlet tubes, respectively, of all the collector units in said first row, each of said wear shields having a longitudinal centerline parallel to the axis of said outlet tube coplanar therewith and defining a common plane parallel to a flow path along Which said stream of gases flows from said inlet connection to said outlet tube, each said Wear shield comprising a concavo-convex base portion bisected by said plane, said concave surface having an outside radius equal to the radius of said outlet tube said concave surface being in general contact with the outer surface of said outlet tube, and two spaced leg portions along the longitudinal edges of said base portion said leg portions having external surfaces radial to the axis of said tube, said leg portions extending obliquely upstream from said base portion.

References Cited by the Examiner UNITED STATES PATENTS 1,894,270 1/1933 Grady 122--235 2,083,764 6/1937 Weisberger 435 2,087,464 7/1937 Ayers 55-462 2,235,539 3/1941 Smith 5543S 2,544,395 3/1951 Polk 55-348 3,078,919 2/1963 Brown -142 X 3,105,544 10/1963 Brown 165142 FOREIGN PATENTS 183,160 7/1922 Great Britain.

OTHER REFERENCES Industrial & Engineering Chemistry, vol. 41, June 1949, pp. 1196-1199, article titled Erosion Due to Dust Particles in a Gas Stream (Stoker).

ROBERT F. BURNETT, Primary Examiner.

HARRY B. THORNTON, Examiner.

Claims

1. IN A CYCLONE COLLECTOR OF THE CLASS HAVING MULTIPLE ROWS OF COLLECTOR UNITS, EACH OF SAID COLLECTOR UNITS COMPRISING A COLLECTOR TUBE COAXIAL WITH A CYLINDRICAL OUTLET TUBE, SAID ROWS OF COLLECTOR UNITS BEING DISPOSED TRANSVERSELY OF A STREAM OF GASES HAVING ABRASIVE PARTICLES ENTRAINED THEREIN, SAID STREAMM OF GASES ENTERING SAID CYCLONE COLLECTOR THROUGH AN INLET CONNECTION, A FIRST ROW OF SAID COLLECTOR UNITS NEAREST SAID INLET CONNECTION BEING EXPOSED TO WEARING EFFECTS OF SAID ABRASIVE PARTICLES: THE IMPROVEMENT COMPRISING THE COMBINATION OF INDIVIDUAL ELONGATED WEAR SHIELDS MOUNTED ON THE UPSTREAM SIDES OF SAID OUTLET TUBES, RESPECTIVELY, OF ALL THE COLLECTOR UNITS IN SAID FIRST ROW, EACH OF SAID WEAR SHIELDS HAVING A LONGITUDINAL CENTERLINE PARALLEL TO THE AXIS OF SAID OUTLET TUBE COPLANAR THEREWITH AND DEFINING A COMMON PLANE PARALLEL TO A FLOW PATH ALONG WHICH SAID STREAM OF GASES FLOWS FROM SAID INLET CONNECTION TO SAID OUTLET TUBE, EACH SAID WEAR SHIELD COMPRISING A BASE PORTION NORMAL TO SAID PLANE AND TWO SPACED LONGITUDINALLY PARALLEL LEG PORTIONS SUBSTANTIALLY PARALLEL T SAID PLANE AND EQUIDISTANT THEREFROM AND SAID LEG PORTIONS EXTENDING DOWNSTREAM FROM THE LATERAL EDGES OF SAID BASE PORTION FAR ENOUGH TO MAKE LINE CONTACT WITH THE EXTERNAL SURFACE OF SAID OUTLET TUBE.