US2675274A

US2675274A - Self-discharging bin

Info

Publication number: US2675274A
Application number: US280936A
Authority: US
Inventors: George K Engelhart
Original assignee: Fuller Co
Current assignee: Fuller Co
Priority date: 1952-04-07
Filing date: 1952-04-07
Publication date: 1954-04-13
Anticipated expiration: 1971-04-13
Also published as: GB724320A

Description

April 3, 1954 a. K. ENGELHART sswpxscmcmc BIN IN V EN TOR.

4 Sheets-Sheet l LNJ Filed April 7, 1952 Ap 3, 1954 G. K. ENGELHART sawoxscmmemc BIN 4 Sheets-Sheet 2 Filed April 7, 1952 was.

.T mw n w? G o N T Mm E, 6V. R M FOP I G M M April 3, 1954 G, K. ENGELHART 2,675,274

SELF-DISCHARGING BIN Filed April 7, 1952 4 Sheets-Sheet 3 so 55 IN V EN TOR. FI '7- 62 55- 6mm,: KEN T LHFAR :HTTORNEY April 13, 1954 s. K. ENGELHART SELF-DISCHARGING BIN 4 Sheets-Sheet 4 Filed April 7, 1952 IN V EN TOR.

BY GEORGE K-ENGELHHRT f v M W Patented Apr. 13, 1954 2,675,274 SELF-DISCHARGING BIN George K. Engelhart, Catasauqua, Pa., assignor to Fuller Company Application April '7, 1952, Serial No. 280,936

This invention relates to apparatus for storing and discharging pulverulent material, and par ticularly to mobile storage carriers and means associated therewith for discharging substantially-dry, finely-divided material from them.

The apparatus and method of the invention are especially designed for conveying and discharging large quantities of pulverulent materials, such as flour and other pulverulent food products, dry finely-divided chemicals, and other finely-divided materials, especially those which do not flow freely from ordinary storage receptacles.

It is well known that flour is particularly susceptible to infestation by insects if kept within it a storage receptacle for any appreciable length of time. It is also well known that it is diflicult to discharge flourfrom a large receptacle without expensive and complicated apparatus. ,Ac-

cordingly, it has been customary in the past to load flour from storage bins at the mills into large bags, and to transport the bags to the various places where the flour is to be used, which places are frequently at substantial distances from the mills. It is desirable to avoid the added operation of loading the flour into bags, because of the cost of the operation itself, the cost of the bags, and the danger of contamination of the flour during the loading procedure.

Apparatus has previously been designed to discharge flour from vehicles, but such apparatus has been objectionable because of wastage of the flour, failure of complete removal of the flour when it was discharged, or dusting by the material of the area around the vehicle during the dis- In transporting certain dry chemicals, it previously has been necessary that they first be stored in small containers before they could be shipped to the remote locations at which they were to be used, because of the deficiencies in known methods for transporting such chemicals in bulk, and particularly because of wastage of the chemicals and deposit of them in undesirable places. In some of the previous methods-and apparatus designed for discharging expensive 3 Claims. (01. 302-52) chemicals, such as adipic acid, from a bulk receptacle, the wastage of the chemical during the discharge operation was so great as to make transporting in bulk expensive and inefiicient.

Moreover, when deposits of material were left in the receptacle after discharge, it was not possible to transport difierent chemicals in the same receptacle later because of contamination by the earlier-transported chemical. The apparatus and method of the present invention are designed to discharge pulverulent material, such as adipic acid, from a large mobile bin or container, such as a railroad car or a truck trailer, without permitting any appreciable wastage or contamination of the material and without permitting deposits of material to remain in the bin after the material is discharged therefrom. The apparatus of the present invention comprises generally a mobile bin having walls defining an enclosed storage space, a substantiallyvertical conveyor pipe suspended from the upper wall of the bin and extending down into the material contained in the bin, a curtain pipe surrounding the conveyor pipe and having an opening positioned above the level of material in the bin for admitting air from the storage space into the passage between the conveyor pipe and the curtain pipe, means for applying a suction pressure to the upper end of the conveyor pipe, and an opening through one of the walls of the bin for admitting air from the atmosphere into the bin. This apparatuspermits air entering the bin through said opening to sweep over the material contained within the bin, to enter the passage between the conveyor pipe and the curtain pipe, and to pass downwardly through that passage across the surface of material below the conveyor pipe, to entrain such material and to pass upwardly through the conveyor pipe out of the bin, where the air-entrained material may be packaged or delivered to some convenient remote location.

The aboveapparatus in itself is capable of'over coming most of the disadvantages present with previously-proposed transportable-bin discharge apparatus. But a large amount of power is necessarily consumed in entraining the material stored in the bin in the air stream, so that the entrained material can be carried out of the bin. The lower end of the conveyor pipe is necessarily positioned quite close to the lower wall of the bin, so that all or substantially all of the material contained within the bin can be discharged. The weight of the material itself. will cause the material below the lower end of the conveyor pipe to be formed sary velocity of the air, and consequently the power that must be supplied to the suction apparatus, is appreciably reduced. Accordingly,-

the present invention contemplates p-roviding within the bin one or more gas-permeablemem bers having their upper orv material-conveying surfaces forming at least portions of the bottom. wall of the bin, the gas-permeable members being inclined with respect to the horizontal, and having their lowermost en'ds positioned adjacent the lower end of the conveyor pipe. Each of the gas-permeable members has a plenum chamber extending along and below it intowhich a gas is forced so that'the gas passes through the gas;- permeable members and into the material supported thereby to "aerate such material. The aerated material then flows downwardly along the upper surface of the gas-permeable members by gravity to-a location below the lower end of the conveyorpipe where it can be picked up'by the air stream from the curtain pipe.

The method and preferred embodiments of the apparatus of the present invention will be more fully described in conjunction with the accompanying drawings.

In the drawings:

Fig. l is'avertical sectional view taken on line |--l' of Fig. 2 of a freight car embodying the present invention;

Fig. 2 is a horizontal sectional view on line 2 2 of Fig. 1; V Fig. 3 is a vertical sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is a view of a portion of the apparatus shown in Fig. 3 drawn to a larger scale; I

Fig.5 is a vertical sectional view taken on line 5-5 of Fig. 6 of a truck trailer embodying the present invention; 7

Fig. 6 is a horizontal sectional view taken on line 6-6 of Fig. 5; and

Fig. 7 is a sectional view of a portion of the apparatus taken on line '!--'i of Fig. 5.

In Figs. 1 through i, the invention is shown as embodied in a freight car having an upper wall 2,

end walls

3 and 3, side walls 4 and 4', and a bottomwall 5 defining an enclosedmaterial-storage space 6. A pair of conveyor pipes T and 7 extend substantially vertically within the storage space 6 approximately equidistantly between the

end walls

3 and 3. The'conveyor pipes i and l are spaced apart laterally; both from themselves and from the-side walls 4 and lv The upper portions of'the conveyon. p i-pes 1 and l" extend through the upper wall gene the roof 8 of the car into two of a numberiof access ports 9 and 9', respectively, which provide loading e'ntrancesto the storage space 6. The upper portions, of the conveyor pipes are supported from the upper wall by clamps I9 and Ill attached tothe upper wall. Clamps l0 and I0 have split rings It and H" surrounding the conveyor pipes 1 and. 1, respectively. The split rings are clamped about the pipes 1 and 1" by bolts [-2 and i2, respectively, which connect the split ends of the rings. The bolts may be loosened to permit the conveyor pipes to be adjusted upwardly and downwardly to permit adjustment of the lower ends I3 and I3, respectively, of the conveyor pipes 1 and I with respect to the portion of the bottom wall 5 of the bin immediately beneath them. The lower ends of the conveyor pipes are spaced above the lowermost surfaces of the bottom wall 5 of the bin a distance determined by the type of material being conveyed and the desired rate of flow of the material.

Curtain pipes I4 and i4 surround the conveyor 7 pipes I and 1', respectively, and are spaced therefrom by spacers l5 and I5, respectively, mounted on conveyor pipes 1 and l. 'Ihe'curtain pipes 14 andJd are supported from the upper wall 2 by mounting plates I6 and 16' through which bolts I! and I8, and I1 and I8, respectively, are threaded. The lower ends of boltsfl and I8 and I1 and I8 are Welded or otherwise fixed to the upper ends of the curtain pipes l4 and It, respectively. The threaded bolts permit the curtain pipes to be adjusted vertically with respect to the upper wall of the bin, so that the positions of the lower ends of the curtain pipes may be varied with respect to the lower ends of the conveyor pipes I and 1'. It has been found that in most instances the most desirable position of the lower end of each of the curtain pipes with respect to the lower end of each of the associated conveyor pipes is suchthat the lower ends of the conveyor pipes lie in the same planes as the lower ends or the curtain pipes. However, the settings of the curtain pipes with respect to those of the conveyor pipes are determined by the type ofmaterial conveyed and may be different for difierent materials.

Suction discharge conduits for connecting the top of'the conveyor pipes I and T to a remotely located storage bin or the like, and for applying suction to the conveyor pipes to cause discharge of the material therethrough, are indicated in dotted lines at [9' and I9.

The freight car I has a pair of

end walls

20 and 20" spaced inwardly from the

end walls

3 and 3, respectively, of" the bin to provide

air spacesor chambers

20 and 20, respectively, at each end of thecar. Openings 2! and 2! in the end walls 3 and 3', respectively, allow air to pass into the air spaces or chambers 20+ and filter units also remove entrained materialfrom any air which might pass out of the bin through the openings 2! at 2|.

The upper ends of the walls 20 and 20' terminate below the upper wall" 2 of the car, and a battle having laterally-extending

surfaces

23 and 23", and longitudinally-extending

surfaces

23 and 23 extends downwardly from the upper wall, the surfaces 23- and' 23' being'adjacent the walls 20 and 20-", respectively, sothat air admitted through the openings 2! and 21' must pass through filter units 22 and 22' and then flows upwardly and over the upper ends of walls 20 and 20' which then direct it downwardly against the upper surface of material in the bin.

In order to convey material from within the storage space 6 to positions beneath the conveyor pipes 1 and 1', four gas-

permeable members

24 and 24' and 25 and 25- are provided. The laterally-spaced gas-

permeable members

24 and 24" extend from the .wall 20, and the laterally spaced gas-permeable members 25 and 25' extend from the wall downwardly and terminate beneath the conveyor pipes l and 1' with their lowermost ends abutting.

Plenum chambers 26 and 26' and Z! and 27' extend along and below the gas-

permeable members

24 and 24 and and 25, respectively. Means for forcing gas under regulated pressure into the plenum chambers are indicated diagrammatically at 2B and 29. Such gas-forcing means may be a single apparatus and may be carried on the car or may be kept at discharge locations for connection to the plenum chambers when the car reaches the locations.

In order to direct material within the car onto the upper material-conveying surfaces of gas

permeable members

24 and 24' and 25 and 25, the bin is provided with flow-directing surfaces. These flow-directing surfaces comprise an in clined wall extending between side wall 4 of the car and the adjacent sides of gas-

permeable members

24 and 25, an inclined wall 30' extending between side wall 4 of the car and the adjacent side of gas-permeable members 2:4 and 25' and inclined walls 3| and 3! aligned to form an inverted V in cross-section, with their lower edges positioned at the adjacent throughout the length of the plenum chambers and passes from them through the gas-permeable members, thus aerating the material immediately overlying them. The aerated material flows downwardly by gravity along the upper surfaces of the gas-permeable members to positions beneath the lower ends of the conveyor pipes I and i and the curtain pipes l4 and I l. The means i9 and IQ for supplying suction to the conveyor pipes I and 1', respectively, are then set into operation and air entering from the atmosphere through the openings 2| and 2| in the end walls of the freight car passes through the filter units 22 and 22' across the material in the bin to the curtain pipes 14 and it. Since the openings are located at substantial distances from the curtain pipes, the air must.

pass over most of the upper level of the material in the bin before it reaches the curtain pipes. Consequently, the air will sweep all dust formed above the level of material along with it, thus decreasing appreciably the. possibility of a dust,

explosion in the car. Thestream of "air'then passes up over the upper ends of the curtain pipes and downwardly through the passages between the curtain pipes and the conveyor pipes and across the material beneath the conveyor pipes and the curtain pipes. At these points the air entrains the aerated material and carries it upwardly through the conveyor pipes into the

access ports

9 and 9, then through conduits l9 and is out of the bin and to the remotely-located storage'bin from which it later is packaged or used.

The term aeration is employed herein to mean penetration of any gas, not necessarily air, I a into the material above the gas-permeable memnition would be zero.

bers at sufficient speed to expand the material, and thereby reduce the particle-to-particle friction, but not at a speed sufflcient to entrain particles of material in the gas stream.

When a pulverulent material is aerated by passage of a gas through a horizontal permeable member into it, it forms a definite angle with respect to the horizontal gas-permeable member. This angle is termed the angle of repose of the aerated material, and is substantially less than the angle of repose of the same material before aeration. If the gas-permeable member is inclined with respect to the horizontal at an angle at least as great as the angle of repose of the aerated material, aeration of the material will cause the material to flow by gravity along the conveying surface of the permeable member to the lowermost end thereof. The angle: of repose of an aerated pulverulent material is dependent upon the characteristics of the particular material, and varies with different materials. However, it has been found that if the gas-permeable member has an inclination with respect to the horizontal of from about 4 to about 15, practically any material which may be aerated will, when aerated, flow down such a member by gravity. Accordingly, the gas-

permeable members

24 and 24 and 25 and 25 are preferably disposed such that their upper or materialconveying surfaces form an angle with respect to the horizontal at least as great as the angle of repose of the material in its aerated state.

It is not necessary that air be used to aerate the material. The gas fed into the plenum chambers 26 and 2S and 21 and 2'! may be any gas which is inert with respect to the particular material in the storage space 6. The gas may be also heated or refrigerated, and, in some cases, it may be a gas which is chemically reactive with the material, depending upon the particular material and the characteristics which it is to have when discharged from the car. The gas-

permeable members

24 and 24' and 25 and '25 are advantageously constructed of canvas,

but may be of any gas-permeable material having a permeability not substantially greater than 5. The term permeability as herein. employed is defined as the amount of air measured in cubic feed at 20 F. and 25% relative humidity which will pass through an area of one square foot of dry, porous stone in one minute when tested under an equivalent pressure differential of two inches of water.

It has been found that porous material having a permeability of from about 5 down to and including zero, as determined by the above definition, is satisfactory for use as the gas-permeable members in the apparatus of the present invention, and, accordingly, porous material having a permeability within that range is preferred for use with the present invention, in the case of may not cause a considerable volume of air to pass through the material, so that the permeability measured in accordance with the above defi- If such is the case, the resistance to gas flow of the gas-permeable material should be such that with an air fiow of l 0. F. lVL/sq. ft. through the uncovered medium, i. e., free of the material to be conveyed, a pressure differential of at least three inches of water across the gas-permeable material is produced.

. 1.353 :end walls :34 ethereal strand; a bottom well 5515 defile-mg :an enclosed storage space 1,. .:A conveyor pipe 5.8 extends substantially vertically within the store-seepa e :31, and-has'zitsupper end projecting into'onesofia nurnberotflongitudinallyspaced access ports 39 which :are provided for loading of material .into the storage space. :The

,conveyor pipe as is supported from the upper wall .35 of the binby-asplit ring-clampipgmeans t2. The upper end :of the curtain pipe is *adjnstablysupportedfrom theroof 3'5-of the storage space "means generally indicated at 43, -which is --similar to that shown inFig. '4 and, therefore, [not further described.

The adjustable supporting means or both the conveyor pipe :and the curtain pipe allow them to be adjusted wertically :to suitable positions above the bottom wall 35,171,143 positions being :determined by the material being conveyed.

Four longitudinally-extending gas-permeable members ii -i and at and {i5 and 35 are mounted in the bottom wall of the-truck. The gas-permeablemem-bers 4;! and :44 extend between end wall t l-and points substantially midway between the end --walls 5:41 341111134. The gas-permeable members and 45 extend from end wall 34 to points which also are substantially midway between the end walls '34 and 134. 'The gas-permeable zmembers M and 44' and .45 and 45 are preferably all inclined with respect :to the horizontal at an 52111216 at least equal to the angle -:Of repose not the material in itsaeratedstate. and havetheirupper ends plaeedagainstthe end walls -:34:and"34'., respectively. Plenum chambers #6 and "4.6" and 41 and 4 extend .;along and below the gas-permeable members M and W and Miami 4'5,-respectively. Gas under pressure :is furnished to the plenum chambers through gas-pumping means indicated generally at 4-3 and 139, which may be a single apparatus and may be carried on the trailer or retained .at discharge locations 'for attachment to the plenum chambers when the trailer'reaches such locations.

The lower ends of the gasepermeablemembers 4s and c5 discharge-ontoi-the upper endaof atransversely-extending,egasepermeable member 5B,;and the lower ends of the gas-permeablemembers 44' E5" discharge onto a 'transversely extending, gas-permeable :nrember-fiil., .aligned with the gaspermeable member 59. The'gas permeahle members 59 and say are preferably inclined downwardly towards the center of the truck at an angle-at least equal to the angle of repose of the material in its aerated'stateand have their ends terminating below and adjacent the open lower .end ofthe conveyor'pipeeil'. Plenum-chambers 5| land 5|" extend along and beneath the gas- ..permeable members 5.0 andlifi', respectively. The

thegas-permeablemembers50.:andll'. The plus gas-permeable members :50 and :50, respectively,

and which form in cross-section, -,a flattened 'V. The plug 52 is provided to permit discharge of material through the lower end of the bin, if

such discharge should become desirable for .an

reason. The-truck has a pluralityof :flow-directingsurfaces for directing-rmaterial in the storage space 3'] onto the upper'or material-conveying surfaces .ofthe gas-permeable members 44 and 44' :and di and 45'. .These flow-.direotingisurfacescomprise members 54 and 54rextendingiiromlsidewalls;33 V

and 33f respectively, downwardlytame-adjacent .sides of the adjacent gas-permeable members,

and surfaces end 55 which form ani-nver-ted -.V incross-sectionand have-their lower ends connected tothe adjacentsidesof the gas-permeable members. 'The flow directing surfaces are all inclined with respect to the horizontal at angles large enough so that the material "flows .along them onto the gas-permeable members .bygravity.

A filterunit56 isecarriedrin-a compartment 5'! mounted on-end wa11r3.4-0f the truck. This compartment has an air-intake opening as at its outer side and discharges air after .its passage through the filterzuni-t through the end wall -34' intothe storage space 31. .Thelilter unit 56 has the same function as the filter :units 22 and 22' described in conjunction with the apparatus of Figs. '1 through 4 and, therefore, -i-s.not further described here.

-.A conduit 59 may be connected to theupperiend of the conveyor pipe 38 {to apply suction tothe conveyor pipe, and :to conduct air and-material from the conveyor pipe to .a storage bin or the .like.

In operationrof theapparatus described in .connection with Figs. .5 through 7,;gasunderpzessure is forced into the plenum chambers lit 74.5 and 41 and 4:7 and 5.1 and .5 l i, .throughmeans ta and '49. The gas flows through the gas-permeable members .and 4.4245 and-A5 andbil and 5E! into "the overlying-material on the upper remotely located or material-conveying sun-faces .of the gas-per- -meab1e members, thus aerating the material.

The aerated material flows downward by the actioniof gravity from the ends of the bin along the upper surfaces :of gas-permeable members 44 and -44 :and -45 and 45, until .it is discharged .onto the.gas-permeablezmembeis-50 and so, at which time it flows laterally of the bin downsvardly along the .upperisurfaces of the gas-permeable members 50 and .50, onto the upper sur- ;faces-53 and 53".of thedischarge plug 52. Air then passes through the opening 58 in the coinpartment 15:1 and the filter unit 56 in suehcoinpartment into the :material storage space :Since the opening 58 is ilocated at :a substantial distance from the curtain pipe 1 l. the :air passes "over most of the upper surface of the-material aerated material it reverses its :direction and passes upwardly through the conveyor pipe out of the bin into the transporting means 59. Thus the material within the bin is discharged and conveyed to the proper remote location.

Although the use of air from the surrounding atmosphere as the medium for entraining and carrying the pulverulent material out of the bin has been referred to exclusively above, since atmospheric air is the most convenient and economical gas for the purpose, it is obvious that heated or refrigerated air or other gases, such as those chemically reactive with the material, could be utilized if the results achieved. from their use were desired. Accordingly, the invention is not to be considered as limited to the use of air but encompasses the use of such other gases. When the word air is used in the appended claims, it is to be understood that such other gases could be substituted therefor.

Though the apparatus and method of the present invention have been described in conjunction with vehicles, such as railway cars and truck trailers, it is obvious that the apparatus is capable of application to any material-storage bin for pulverulent material. Accordingly, the

invention is not to be considered restricted to a use with vehicles or other mobile bins. Moreover, many other modifications could be made in the apparatus described, without departing from the scope of the invention. Consequently,

the invention is not to be considered limited to -I the apparatus and method specifically shown and described, but rather is limited only by the scope of the appended claims.

I claim:

1. Apparatus for storing and discharging sub,

stantially dry pulverulent material comprising a substantially closed bin, at least one upwardly extending conveyor pipe in the bin having its lower intake end adjacent but spaced above the bottom of the bin, a curtain pipe enclosing and spaced from the conveyor pipe and having its lower end adjacent the lower end of the conveyor pipe, said curtain pipe communicating with the space in the upper part of the bin for receiving air therefrom, means for introducing air into the upper portion of the space in the bin at a point remote from the intake to the curtain pipe to flow across the upper surface of pulverulent material in the bin for introduction into the curtain pipe, means including at least one gas-permeable member in the bottom of the bin for delivering pulverulent material in the bin in an aerated state to a location beneath the conveyor pipe, said gas-permeable member having an upper material-conveying surface forming at least a portion of the lower wall of the bin and being inclined with respect to the horizontal, said gaspermeable member having its lowermost end positioned adjacent the lower intake end of the conveyor pipe, a plenum chamber extending along and beneath the gas-permeable member, and means for introducing a gas into the plenum chamber to pass through the gas-permeable member into material on the material-conveying surface thereof to aerate such material, whereby material on the material-conveying surface of the gas-permeable member flows therealong in an aerated state to aposition beneath the lower intake end of the conveyor pipe to be entrained by a stream of air discharged from the lower end of the curtain pipe and to be carried by the air stream upwardly through the conveyor pipe out of the bin. 7

2. Apparatus for storing and discharging substantially dry pulverulent material comprising a bin, at least one upwardly-extending conveyor pipe in the bin having its lower intake end adjacent but spaced above the bottom of the bin, a curtain pipe enclosing and spaced from the conveyor pipe and having its lower end adjacent the lower end of the conveyor pipe, said curtain pipe being adapted to supply air to the lower end of the conveyor pipe for the entrainment of pulverulent material to be discharged through the conveyor pipe, and means for delivering material in an aerated state to the lower end of the discharge pipe, said means including at least two gas-permeable members in the bottom of the bin and extending in the sam general direction, said gas-permeable members being inclined with respect to the horizontal and having their lower ends at opposite sides of and ill spaced from the lower end of said conveyor pipes, other gas-permeable members in the bottom of the bin extending transversely to said first gaspermeable members and positioned to receive aerated pulverulent material from said first gaspermeable members, said other gas-permeable members being inclined with respect to the horizontal and having their lowermost ends positioned adjacent the lower intake end of the conveyor pipe, each of said gas-permeable members having an upper material-conveying surface forming at least a portion of the lower wall of the bin, a plenum chamber extending along and beneath each of said gas-permeable members and means for introducing a gas into each plenum chamber to pass through the overlying gas-permeable member into material on the material-conveying surface thereof to aerate such material, whereby material on the material-conveying surface of the gas-permeable members flows therealong in an aerated state to a position beneath the lower intake end of the conveyor pipe to be entrained by a stream of air discharged from the lower end of the curtain pipe and to be carried by the air stream upwardly through th conveyor pipe out of the bin.

3. Apparatus for storing and discharging substantially dry pulverulent material as set forth in claim 2 in which th bin is substantially closed, the curtain pipe communicates with the space in the upper part of the bin for receiving air therefrom, and means are provided for introducing air into the upper portion of the space in the bin at 9. point remote from the intake end of the curtain pipe to flow across the upper surface of pulverulent material in the bin for introduction into the curtain pipe, whereby air so flowing across the upper surface of the pulverulent material will entrain dust particles.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 412,388 Hungerford Oct, 8, 1889 528,417 Duckham Oct. 30, 1894 1,390,974 Von Porat Sept. 13, 921 2,027,697 Nielsen Jan. 14, 1936 2,190,726 McKenna Feb. 20, 1940 2,418,302 Hornbrook Apr. 1, 1947 2,545,766 Cline Mar. 20, 1951 2,565,835 Adams Aug. 28, 1951 2,589,968 Schemm Mar, 18, 1952 2,602,707 Garoutte -1 July 8, 1952 2,647,802 Hornbrook Aug. 4, 1953