US2759614A - Anti-clogging device - Google Patents

Description

Aug. 21, 1956 STQCK I I 2,759,614

ANTI-CLOGGING DEVICE Filed May s,' 1951 Y 4 Sheets-Sheet 1 INVENTOR 31%, a waww ATTORNEYS g- 21, 1956 A. J. STOCK 2,759,614

ANTI-CLOGGING DEVICE Filed May 5, 1951 4 Sheets-Sheet 2 INVENTOR ATTORNEYS Aug. 1, 1956 A. J. STOCK 2,759,614

ANTI-CLOGGINC DEVICE Filed May 5, 1951 4 Sheets-Sheet 3 IN VENTOR ATTORNEYS Aug. 21, 1956 A. J STOCK ANTI-CLOGGING DEVICE 4 Sheets-Sheet 4 Filed May 3, 1951 ATTORNEYS United States Patent ANTI-CLOGGING DEVICE Arthur J. Stock, Cleveland, Ohio Application May 3, 1951, Serial No. 224,401

6 Claims. (Cl.-2142) This invention relates primarily to coal handling. However, its principles are equally applicable to the handling of other aggregate materials.

More particularly this invention relates to the gravity feeding of coal and to apparatus that will facilitate such feeding by the prevention of sticking, wedging, binding, bridging or the like in passages of the apparatus.

Depending upon various factors including fineness, amount of moisture, rate of flow, and size of orifices; coal and other aggregate materials tend to become compacted and to bind, stick, wedge or bridge in passages through which it is intended that they should flow by gravity;

The problems, insofar as coal is concerned, have become more acute in recent years because the coal to be handled has become finer and often wetter. Further, the coal has come to contain larger percentages of clay and other impurities that tend to make it compact moreand hence result in greater clogging problems.

Similar problems to those discussed with coal are encountered in the handling of other like materials as for example fu'llers earth, kaolin and titanium dioxide. Additionally it is to be understood that anything which prevents clogging will open gravity feed systems to use with a wider range of aggregate materials.

Recent advances in coalmining machinery'and blasting techniques have increased the etficiency of coal production, but have also reduced particle size and increased the amount of impurities such as clay and shale. industrial power plants utilize as cheap a coal. as possible and therefore the finest and most impure co'al. Hence serious feeding problems are encountered.

Attempts to overcome these-feeding problems by the simple expedient of using, passages of larger cross-sec tionalarea throughout the system or by the use of 'vibrators locatedat certain points where clogging. is most apt to occur have not proven very satisfactory. Thereis, a practical limit to the size of passages that may be emplayed and vibration, if notproperly applied is likely to cause more compacting and cloggin'g,.instead of preventing it.

In a previous-patent application by the same inventor, SerialNo. 662,802,.filed April 17, 1946, and nowabandoned, ithasbeenproposed to operate. a vibrator only during. periods of coal stoppage. There are distinct advantages in this procedure which are: the vibrator is not nearly so likely to cause compacting of the coal,.the power requirements for. vibrator. operation are lessened, andIthe-attendant noise is notcontinuous. Furthermore, wear:on.the. vibrator. and other parts is lessened. However, even this .arrangementis onlypartially satisfactory.

Whilev this systern-is-the onemost nearly perfectedkthus far, it neverthelesspossesses several-disadvantages. For example, the-weight of. coal inabunker. for alairge central station orlarge. industrial. boiler plant is such that considerable. heavy gaugev steel must he incorporated into it in order for it to carry the: great weight. Inasmuch-as the bunker outletis usually located at .the apex of an inverted pyramid, manyof its. structural members come Naturally,

2,759,614 Patented Aug. 21, 1956 'ice together at the bunker outlet flange thereby producing a very rigid structure in the lower portion of the bunker. Consequently, a vibrator mounted onthis portion of the bunker must be very powerful indeed to accomplish the desired result. Consequently, thevibrational requirements to effectively practice this system are economically unfeasible from a horse-power standpoint.

Another factor' that has prevented successful solution to the problem of coal flow'h'as been the size of the inlets to various apparatus whichperform operations of one kind or another upon the coal; Examples are coal scale assemblies and pulveriz'er' feeders. These apparatus generally have relatively small inlets. Thus, they limit the size of a spout or hopper Ie'adingto such apparatus.

While the problem of coal compacting exists in straight spouts (i. e., spouts of uniformcross-section), it is greatly increased by spouts or hoppers which taper in the direction of coal flow. It is possible to alleviate clogging by using a spout which increases in cross section in" the direction of flow of material. However, the use of spouts of this type make it necessary eventually to reduce a large cross-section coal stream to a small cross-section to get it into the inlet to an apparatus such as a pulverizer feeder or coalscale. I

While the difficulties of gravitational flow have been discussed in conjunction with coal, it is to'be understood that the discussion is equally applicable to other like materials. I

It is an object of this invention to provide a; flexibly supported vibratingoutlet'f'o'r a hopper or spout which will more efiiciently and more economically keep a material such as coal, titanium dioxide, fullers earth,- etc., uncompacted and able to flew from a relatively small outlet.

It' isanotherobject' of this'inv'en'tio'n" to provide a gravitational system for transporting'coal' and the like without stoppages more effectively than any' system that has previously been available.

It:- is another object" of this invention to provide a hopper or" spout outlet that will be readily adaptable for mounting at the bottom of a" standard hopper or spout in orderthat the material contained in the hopper or spout willdischarge therefrom more freely and' regularly.

Itis a further object oftliis invention to provide a hopper or spout'outlet'whieh will enablelarger outlets to" be employed ahead of'it in the system and which wi1lenable the use, ahead of-it in the systqm, 0f spouts which increase in size in'the direction of'fiow of the material to be-utiliz'edl e Other objects and advantagesof the present invention will become-apparent from a detailed study of the following specificatio'n'when considered in conjunction with the acompany-ing drawings in which:

Figure 1 is a view in. front elevation showinga system for transporting coal from a bunker to a pulverizer through a coalscal e; p

Figure 2 -is a view in side elevation similar to Figure Figure 3 is a view in-front elevationshowinga vibrating outlet for a hopper; V

Figure 4- is a view in verticalsection ofi Figure 3- taken alongz-line 44; p 7

Figure 5 is a view in frQnt' elevation partly broken away showing a modified vibrating: outlet for ahopper employing spring supports; v

Figure 6 is a View in section of-Figure 5 taken along line 6-6;. and

Figure 7 is a view in frontelevation partly broken away showing a further modified vibrating outlet for a hopper.

Referring.- nowto the dI'aVVlHgSyFlgUIES' 1 and 2 show an improved system for transporting coal in boiler-plant operation from a coal bunker 23 to a pulverizer feeder 21. The bottom portion of the bunker 2'9 is provided with a vibrating outlet generally designated as 22 which includes an inner hopper 53 which is capable of being vibrated and an outer casing 54. The construction of this vibrating outlet will be considered fully in conjunction with Figures and 6. This portion is detachably joined to the bunker by means of flanges 23 and bolts 24. Mounted beneath the outlet 22 is a standard Seco coal gate valve 25. The operating sheave for valve is shown as 26. On the rear of the valve is a duct cover 27 which permits access to the valve and also removal of the gate. This gate (not shown) is U-shaped and rides on roller-bearing rollers. The top surface of the valve is provided with depending skirts which rest inside of the gate to prevent coal dust and moisture from deleteriously affecting the rollers. Flanges 28 and bolts 29 connect the valve to the bottom of casing 54 of outlet 22.

Beneath the valve is located a coal scale assembly having a feeder belt 30 and a weigh hopper 31 arranged in proper relation. A motor 32 is provided on the side of the assembly to drive the feed belt The inlet 33 to this assembly is flexibly connected to the outlet of the coal valve. This flexible connection will be described in greater detail in conjunction with Figure 3. Immediately below the end of the feed belt 30 is weigh hopper 31 which is mounted with a suitable leverage assembly (not shown) to effect accurate measurements. The bottom 37 of the weigh hopper 31 is pivotally connected to the body of the hopper at 38 to permit discharge there from. This bottom 37 is held normally closed by means of a solenoid (not shown) which is operated responsive to the load contained in the hopper. When a desired weight of coal is held by the hopper, a switching means is actuated which causes the motor 32 driving feeder belt 30 to stop and the solenoid to release the bottom 37. When all coal is used off the bottom 37, the bottom. closes itself by means of a counterweight 55 suitably arranged, and thus closes a second switching means which restarts the motor 32 which drives feeder belt 30. Doors 39 are also at various places on the assembly to allow the inside of the coal scale assembly to be readily accessible for examination or any other desirable purpose.

The coal scale assembly has mounted on its top a switching mechanism that includes a coal switch 40 and a pivotally mounted coal paddle 41. A leveling bar 43 is provided at the inlet to the coal scale assembly in order to establish a fixed level of coal on the coal scale feed belt. When this coal is flowing the switch assembly assumes the inclined position, and when the coal is not flowing the switch paddle assumes the vertical position. In the inclined position the switch is open and in the vertical position the switch is closed. When the switch is closed, the vibrator in 53 is energized electrically.

Depending from the outlet of the coal scale assembly is an expanding downspout 42. The top of the downspout 42 is joined to the coal scale assembly outlet by means of bolts 44 in a suitable manner. At the lower end, the downspout 42 is connected to a vibrating outlet 48. This connection designated as 46, is of the flexible type and is in the form of a slip joint. It is similar to flexible connection 34. The outlet 48 is similar to the outlet 22. The vibrating means in outlet 48 is operated responsive to a switching mechanism (not shown) located either in the pulverizer feeder 21 or below it. This switching mechanism may be any standard type. The operation of this outlet 48 is similar to that for outlet 22. The outlet 48 is joined to the inlet to pulverizer 21 in a usual manner as by flanges 50 and bolts 51.

The system above described will operate to transport coal contained in the bunker 20 to the pulverizer 21 as follows. Due to the nature of coal, it will tend to stick and wedge itself in the bunker 20 and will not gravitationally pass through the small bunker outlet 22. It

will be found that occasionally during operation only the coal immediately above the outlet of 22 can be removed from the bunker and the remaining coal assumes a shape more or less as that indicated by 47 in Figure 1. When this condition occurs, paddle 41 assumes a vertical position, thus starting the vibrator of 22. inner hopper 53 then vibrates. This action tends to shake loose and discharge most of the coal held therein. This enables some of the coal in the bunker 29 to pass down into the outlet 22 by reason of the fact that the connection between the bunker and outlet is of large enough cross section to prevent wedging and sticking of the coal at this point. Additionally, the vibrating of inner hop per 53 causes a shearing of the funnel-shaped body of coal in the plane between the bunker 2t) and the inner hopper 53. Therefore, as long as the outlet 22 can force the coal through its narrow opening into the coal valve 25, the coal will have little tendency to stick or wedge in the bunker 2G.

The coal stream issues from the bunker outlet 22 through the coal valve 25 and onto feed belt 33*. While on the belt 36), the coal actuates the pivotal paddle arm 41 which in turn actuates coal switch 48. The vibrating means (not shown) on outlet 22 is operated responsive to switch it) so that inner hopper 53 is vibrated only when there is a coal stoppage. The coal stream passes into the weigh hopper 31 from the feed belt 3% until a predetermined weight has been received by the hopper 31. When this condition occurs, the feed belt 359 is stopped in the manner previously mentioned. The coal in hopper 31 is weighed by a suitable scale mechanism (not shown) and then discharged from the weigh hopper 31 into the expanding downspout and the cycle is repeated. The bottom outlet 4E3 of the downspout 42 is similar to outlet 22 and consequently the coal stream passes through this outlet in a similar manner into the inlet of pulverizer feeder 21.

A coal stream will not flow satisfactorily through a relatively small-sized opening or spout by reason of its tendency to stick and wedge therein. This condition is greatly exaggerated if the spout is tapered in the direction of flow, that is to say, the cross-sectional area is gradually or abruptly reduced, or the opening leads into a spout or like apparatus having a lesser cross-sectional area than that of the opening. The flow of the coal stream in the latter instances is extremely unsatisfactory. One way in which to have better flow of coal is to provide a breakway, that is, to provide adjacent sections which increase gradually or abruptly in cross-sectional area in the direction of flow of the coal stream. This construction relieves, to a large extent, the tendency of a flowing coal stream to stick. As indicated in Figures 1 and 2, several breakaways are provided in addition to the vibrating outlets 22 and 48 to assure a smooth and continuous flow of the coal stream between the bunker 20 and the pulverizer feeder 21. For example, there is a breakaway between the bottom of bunker 2t) and the top of outlet 22, between the bottom of outlet 22 and the inlet to coal valve 25, between the outlet of coal valve 25 and the inlet to the coal scale assembly, between the bottom of scale hopper 31 and the downspout 42, between the bottom of the downspout 42 and the top of outlet 48, and between the bottom of outlet 48 and the inlet to the pulverizer feeder 21.

Additionally, the cross-sectional area of the expanding downspout 42 gradually increases in the direction of flow of the coal stream and consequently, an infinite number of breakaways are established between the coal scale outlet and the downspout outlet, or if desired the downspout 42 can be considered as one long breakaway.

However, the coal scale outlet is approximately four or five times larger than the inlet to the pulverizer feeder. Also, the outlet of the downspout 42 is approximately six or seven times larger than the inlet to the pulverizer feeder due to the increase in cross-sectional area. Consequently, while the difliculties which accompany the flow of the coal stream have been alleviated tlrrou'glrv the; spout 4-2, nevertheless, a: new problem has been created;- name ly, reducing the coal stream from a cross-sectional area equal to the outlet of spout 42 to a crosss'ectional area equivalent to the inlet to the pu'lverizer feeder. This is accomplished by the present invention by utilizing a vibrating outlet 48' similar to the outlet 22' which is employed with the bunker 20' and the l areakaways above mentioned.

In Figures 3 and 4' is shownone form of a vibrating outlet suitable for use in conjunction with a hopper or tube. As can be seen, a hopper 60' is provided at its bottom with a flange 61. To this flange 61 is joined an auxiliary flange 62' in asuitable manner. The hopper outlet generally designated as 63 is provided at its top with a flange 64. The flanges 61 and 64 and the auxiliary flange 62 having holes 65 at spaced intervals, to permit the outlet 63 to be connected to the hopper 60 by bolts 66, washers 67, and nuts 68 in a conventional manner. Washers 67 are a resilient type of washer such as rubber. Depending from auxiliary flange 62 is a ring 69 having holes 70. The top of the outlet 63 is deformed to also form a ring 71 having holes 72. Interconnected between the two rings 69 and 71 is a resilient member '73 in the shape of a ring. This connection is elfected by means of bolts 74 being passed through holes 70 and '72 and secured by nuts 76 in a conventional manner. Also strips 75 are interposed between nuts 76 and resilient member 73. The holes 65 in the flanges 61 and 64 and auxiliary flange 62 are ofgreater diameter than the bolts 66. The bottom of the hopper 60 lies within the interconnections between the hopper 60 and the outlet 63 to form a skirt 77' which protects the resilient member 73 from being injured by coal flow through the hopper and outlet. This construction also forms a breakaway between hopper 60 and outlet 63. The outlet 63 is rigidly fixed to coal valve 82 by means of flanges 85 on the respective members and bolt and nut assemblies 86 utilized in a conventional way.

A vibrating means 78 of either the electrical, pneu-,

matic, or any other mechanical type is. mounted on the outlet 63 and serves to impart to it a vibratory motion. This is generally effected by means of the flexible connection between the hopper 60 and the outlet 63 and the flexible dust-tight connection designated as 79; This connection consists of an angle flange 80 which is bolted to the top surface 81 of the coal scale housing 88. A ring 83 is fixed to the inside surface of the flange 80. The outlet 84 of the coal valve 82 lies within the flange 80. The space between the flange 80 and outlet 84 and above the ring 83 is packed with a loose material such as cotton rope 89. A resilient material such as a rubber cement or the like is used to cover the cotton rope and seal the connection as at 87. This connection 79 is similar to connections 34 and 46 of Figures 1 and 2.

It is to be understood that the outlet construction above described can be either incorporated into any standard hopper structure initially or any standard hopper structure can be adapted at any time to include it.

To best illustrate the usefulness of the outlet shown in Figures 3 and 4, the following case should be considered. If bunker 60 were filled with coal it would be very ditflcult if not impossible to continuously maintain a gravitational flow of a coal stream through the bunker outlet. This condition would exist primarily due to the coal stream having a great resistance to flow and a tendency to wedge and stick. By means of the arrangement of the present invention, the hopper outlet 63 and the coal valve 82 are capable of being vibrated together generally in a horizontal plane. In so doing, the vibrating outlet 63 and coal valve 82 do not transport the coal or convey it directly, but rather merely maintain the lumps of coal in a continuous state of motion. This prevents the coal from clogging or binding together and permits it to naturally flow gravitationally. Additionally,

a shearing: action. will; be: set: up. in the body; of the coal" in a: plane? between hopper 60: and the' outlet. 631asv men;- tioned conjunction. with: Figures 1. and; 2. Inasmuch as the cross-sectional area. of the: top of outlet 63 is larger than the" cross' sectiona-l area of the opening at the bottom of hopper 60, a breakaway is formed, as previously described, and the coal will have. a tendency to flow intothe outlet: 63 more easily. The cross-sectionalt area. of the opening at the bottom ofhopper 60 is preselected large enough. so that coal will not stick therein. While the precise size of the opening at the bottom of hopper 60 would depend upon the physical characteristics of the material to be contained in the hopper 60, it has been: found that a cross-sectional area of approximately sixfeet: square has proven satisfactory for some installations where coal isthe material. Additionally, the vibrating of the coal valve 82 with the outlet 63 assures passage of the coal therethroughv Also, the coal valve 82 opens into the larger coal scale housing 88 thereby forming a breakaway since the housing 88 presents an increase in cross-sectional area over that of the coal valve. Mounted with the housing 88 is a coal switch 40 and a coal paddle 41 shown in two positions. Also a leveling bar 43 is located in housing 88.

In Figures 5 and 6 is shown a hopper outlet which can be utilized with the apparatus of Figure 1 for use in conjunction With a pyramid -shaped hopper 90. The outlet 91- is joined tothe hopper 90 at its upper end by means of flanges, bolts, and nuts, generally indicated as 92, in the usual way. At its lower end the outlet 91 is connected to adownspout 96 or other apparatus by means of flanges, bolts, and nuts, generally indicated as 97, in a similar known manner. Enclosed within the dust-tight shell 101 of the outlet 91 is a vibrating hopper 102. This hopper 102 is provided on each of its four sides along its upper portion withan angle 103, the legs of which are welded to the side of the hopper 102"; Directly beneath the iron 103 is mounted another angle 104 with its legs: welded to the outer shell 101". Arrangedin the space between the two angles 103 and 104 at each of the four corners of the hopper 102 is a heavy coil spring 105or other suitable resilient mounting means. Along its lower portion, thehopper 102. is provided with an angle I06 along each of its sides for greater rigidity. Each angle 106 is mounted by welding its legs to a side of the hopper 102. Thus the hopper 102 is flexibly supported. Depending from the bottom of the hopper 102 is a skirt 107 to effectively introduce material flowing therefrom into the downspout 96 without damage to the flanged connection between them. The hopper 90 also projects within hopper 102 by means of skirt 108 to prevent the material flowing into vibrating hopper from interfering with the vibrating apparatus. Since the cross-sectional area of hopper 102 at skirt 107 is less than that of downspout 96 a breakaway is formed. Similarly, a breakaway is formed between hopper 90 and hopper 102 as the bottom opening of hopper 90 is of lesser cross-sectional area than the mouth of hopper 102.

The vibrating apparatus is mounted within the shell 101 and along one side of the hopper 102 and consists of the following. A motor 109 supplied by suitable power means is mounted on the top of shell 101 by means of a bracket 112, and drives a pulley 110 through shaft 111. Secured to the side of the vibrating 'hopper 102 at spaced intervals are two ear-like plates 113. A shaft which has two eccentric portions 114 is mounted by means of bearings 116 and angle plates 117 which are bolted to shell 101. Each plate 113 is mounted on an eccentric portion 114. Also an inertia weight plate 118 is mounted on each eccentric portion 114. An inertia weight 120 which is flexibly supported on springs 121 is mounted across the ends of plates 118. A pulley 122 is mounted on shaft 115 and is connected to pulley 110 by means of a V-belt 123.

By this arrangement, operation of motor 109 through its V-belt drive causes the shaft 115 to turn. The eccentric portion 114 causes plates 113 to produce a vibrating motion imparted to the hopper 102 inasmuch as the hopper is spring-mounted and freely capable of such movement. The reaction to the hopper movement is counterbalanced by the inertia weight 120.

Although the outlet 91 is shown in conjunction with a pyramid-shaped hopper 90, nevertheless it is to be understood that it can be used with conical hoppers or bunkers, or other apparatus, if it is desired to produce an effective gravitational flow of material having a tendency to clog or wedge.

In Figure 7 is shown a modified hopper outlet which is similar in many respects to the hopper outlet of Figures and 6. However, instead of employing a spring-mounted inertia weight, plates 118 are bolted to the shell 191 as indicated at 139. In this manner the reaction to the vibrating of hopper 102 is transmitted to shell 101 which transmits a portion of the reaction to hopper 90 through the rigid connection between hopper 9t] and shell 101. Hence there is a small amount of vibration of hopper 90 which tends to assist the flow of coal from hopper 90 into hopper 1&2.

it is to be understood that the several embodiments of my invention shown and described herewith can be modified or changed as to size, shape, and arrangement of parts by one skilled in the art without departing from the spirit of the invention or the scope of the subjoined claims.

What is claimed is:

1. An assembly for gravity discharge of an aggregate material that comprises a bunker having a discharge outlet, a funnel-shaped member, means mounting said member for bodily movement along an elongated axis with its mouth in registry with said outlet, means to vibrate said funnel-shaped member, and means to control the vibration of the funnel-shaped member, including an electrical switch responsive to the flow of aggregate material below said funnel-shaped member.

2. An assembly for gravity discharge of an aggregate material that comprises a bunker having a discharge outlet, a funnel-shaped member, means mounting said member for vertical bodily movement along an elongated axis with its mouth in registry with said outlet, means to vibrate said funnel-shaped member, and means to control the vibration of the funnel-shaped member, including an electrical switch responsive to the flow of aggregate material below said funnel-shaped member.

3. An assembly for gravity discharge of an aggregate material that comprises a bunker having a discharge outlet, a funnel-shaped member, resilient means mounting said member for bodily movement along an elongated axis with its mouth in registry with said outlet, means to vibrate said funnelshaped member, and means to control the vibration of the funnel-shaped member, including an electrical switch responsive to the flow of aggregate material below said funnel-shaped member.

4. An assembly as defined in claim 1 wherein the mouth of said funnel-shaped member is larger in cross section than said discharge outlet, thereby providing a breakaway therebetween.

5. In a system for the gravity feeding of coal including a bunker, a coal scale, and a pulverizer feeder, the improvement that comprises a funnel-shaped member, means mounting said member for bodily movement along an elongated axis with its mouth in registry with the outlet of said bunker, means to vibrate said funnel-shaped member, and means to control the vibration of the funnelshaped member, including an electrical switch responsive to the flow of aggregate material below said funnel-shaped member.

6. In a system for the gravity feeding of coal including a bunker, a coal scale, a pulvizer feeder, and a downspout connecting said coal scale and pulvizer feeder, the improvement that comprises a funnel-shaped member, means mounting said member for bodily movement along an elongated axis between said downspout and said pulverizer feeder with its mouth in registry with the outlet of said downspout, means to vibrate said funnel-shaped member, and means to control the vibration of the funnel-shaped member, including an electrical switch responsive to the flow of aggregate material below said funnel-shaped member.

References Cited in the file of this patent UNITED STATES PATENTS 1,831,596 Harper Nov. 10, 1931 2,246,497 Beck June 24, 1941 2,346,882 Vredenburg Apr. 18, 1944 2,433,684 Damond Dec. 30, 1947

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