US2355244A - Conveyer for combustion apparatus - Google Patents

Description

A ug. 8, 1944. c. scHoLl.

CONVEYER FOR COMBUSTION APPARATUS Original Filed Oct. 17, 1938 C Nw Patented Aug. 8, 1944 2,355,244 CONVEYER FOR COMBUSTION APPARATUS Clal'k Scholl, Springfield, (Ehio, assigner to The Y Steel Products Engineering Company, Springfield, Ohio, a corporation of @hic Original application October 17, 1938, Serial No. 235,328. Divided and this application December. 10, 1941, Serial No. 422,1ll9

(Cl. ISB-64) 5; Claims.

Thisinvention relates .to stokers and more particularly to stokers making use of a Worm eed.

It is the principal object of the invention to provide a Stoker for feeding solid fuel from a bin to a retort which is relatively light in weight, which feeds fuel at a proper controlled rate and with a minimum of crushing of the fuel, and which utilizes a minimum of power to effect the feeding operation.

It is a further object to provide a feeding device for use with a bin containing a quantity of solid fuel in which the feeding member may be lwithdrawn from and replaced in the loaded bin for inspection or repair.

It is a further object to provide a sectional Worm shaft having a universal coupling therein over which the fuel is adapted to be fed substantially without obstruction.

Itl is a still further object to provide a feeding mechanism for supplying solid fuel to a retort and for effecting the delivery of the fuel upwardly into the retort with a minimum of churning and crushing of the fuel therein.

It is another object to provide a Stoker of this character which is flexible in its application so that it may be readily adapted for operation with different sizes of furnace, different spacings from the fuel bin, and so forth.

Other objects and advantages will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawing Fig. 1 is a view partly in vertical section and partly in elevation showing the feeding worm extending into a bin for receiving solid fuel;

Fig. 1a is an extension of Fig. 1 showing the retort and the drive means for operating the feed germ, Fig. 1a fitting on the right hand end of is. l; i

Fig. 2 is a partial vertical sectional view through the portion of the feeding device which is within the bin on the line 2-2 of Fig. 1;

Fig. 3 is an end elevational view of the feeding device shown in Fig. 1 from the interior of the bin;

Fig. 4 is a detail lview in elevation showing a universal coupling member for the worm shaft.

The present application is a division of application Serial No. 235,328, filed October 17, 1938.

In the feeding of solid fuel such as from a bin containing a supply of solid fuel into a retort, difficulty has heretofore been encountered in securing the feeding of the fuel at a proper controlled rate, and-under such conditions as to avoid crushing of the fuel and the packing of the conveyer ymeans through which the fuel is fed. If the fuel is caused to be churned or crushed during its feeding toward the retort, or if the conveyer means becomes packed or choked with fuel during the course of the feeding operation, an inefcient operation results, requiring the use of unnecessarily large driving forces to secure the delivery of fuel to the retort. And even where supplied under such conditions, the crushing of the fuel tends to reduce the size unnecessarily, thereby changing the combustion characteristics of the retort, resulting in non-uniform and less desirable operation of the retort.

In accordance with the present invention proper control of the feeding of the fuelinto the retort is secured with substantial elimination of objectionable churning and crushing of the fuel during the feeding operation, and with the feeding of a proper and regulated amount of solid fuel into the conveyer means so that the conveyer does not become choked or packed with fuel but receives only that proper quantity which can be transmitted and conveyed readily and with a minimum usage of power. The invention further provides a highly flexible construction adapted to be installed in furnaces of varying dimensions, making use of a standard operating construction, which is simply and readily adapted to the particular size requirements of the installation in a very economical manner. The invention thus provides a highly effective overall stoker installation for feeding solid fuel which is applicable to deliver solid fuel in proper condition and with a minimum power requirement from the bin directly into the retort.

As sometimes occurs in the course of the operation of a stoker of this character, it becomes necessary to Withdraw and replace the feeding worm within the bin. Heretofore when such operation was required it was usually necessary to remove a substantial portion of the solid fuel from the bin in order to replace the feed worm therein. However in accordance with the present invention the entire feed worm may be easily withdrawn from a loaded bin, and may likewise Vbe easily replace in the loaded bin Without the necessity for removing the fuel therefrom.

Referring to the drawing which discloses a preferred embodiment of the invention, the inner wall of the bin is shown at I0 with the feeding device extending adjacent such wall to provide for substantially complete delivery of all of the fuel within the bin. The structure of the feeding device comprises a bearing member Il for receiving the worm shaft I2 and supporting the inner end thereof within the bin. The bearing member II is formed as a section of tube or pipe welded at opposite sides to upwardly extending bracket arms I3 which in turn are bolted to a frame structure comprising angle posts lll and an inverted channel section I5, the latter eX- tending substantially throughout the bin and toward the delivery end of the worm.

The worm shaft I2 is of substantially constant diameter throughout, and has formed on its surface a spirally arranged conveying flight I6. The flight I6 is of uniform pitch and also substantially uniform as regards thickness so that the entire worm shaft is relatively of light weight and simple of manufacture.` The face of the flight is of a Varying width so as to provide aV flight tapering in width from the inner end of the bin to the delivery end thereof. Preferably the smaller portion I1 ,of the flight which is received withinthe bearing II is of a constant diameter to provide for properly guiding and supporting the inner end of the shaft. At the delivery end ofthe bin there is arranged a conveyer tube 2U into which the shaft I2 extends, and the larger diameter portion of the ight 2l which lies within the delivery tube is likewise of substantially constant diameter to provide a uniform 'feeding action for the solid fuel as it is carried through the conveyer tube. That portion of the conveyer flight between the terminal parts I1 and 2| is of the tapering width as described, being preferably of uniformly increasing width of face between said two terminal portions. 'Ihe entire conveyer worm is preferably cast as an integral unit.

The worm shaft is thus exposed on its upper face to engage and deliver the solid fuel contained within the bin. Beneath the shaft there is provided a trough 25, either arcuate in cross section or in the form of an open V-shaped member as shown for simplicity of manufacture, the walls of which are spaced uniformly with respect to the flight I6. It is found desirable to provide certain clearance between the side walls and the flight to avoid undesired rubbing of the parts upon each other under the shifting movement occurring in the conveyer shaft during operation, a clearance of about 1/4" at each side having been found satisfactory. The trough 25 slopes clown-- wardly in the direction of the delivery end of the conveyer, cooperating with the tapered flight on the shaft for properly receiving and conveying the solid fuel picked up by the worm with a `minimum of churning and crushing thereof. Such coordinated construction of tapered Hight on the conveyer and the trough likewise serves to limit the quantity of fuel transmitted by the worm and carried thereby toward and into the conveyer tube 20, the shallower depth of face of the inner portionV of the flight avoiding the collection and movement over the trough of an excessive quantity of fuel such as to cause packing of the conveyer and the collection of a larger quantity of the solid fuel at the entrance to the conveyer tube than can be properly conveyed therethrough. Further inasmuch as the portion 2l of the conveyer flights within the conveyer tube is of larger diameter and hence of greater transmitting capacity than the tapered portion of the flight which receives the solid fuel, assurance is provided that all of the fuel delivered into the conveyer will be properly transmitted therethrough without packing or collecting therein. Further the fuel is not churned around and crushed by the exposed portion of the worm but is caused to feed forward smoothly and easily over the trough with a minimum usage of power.

At the inlet end of the conveyer tube there is preferably provided a shear plate 21 which may Y be removed as required in order to secure access lll to the conveyer at thev point of entrance to the tube, such as to remove solid objects that might be present in the solid fuel and which would make it impossible for the conveyer to operate. A suitable construction of shear plate for this purpose is shown in the patents to Burton 1,905,342 and 1,946,776 assigned to the same assignee as this application. A short section of tubing 24 extends from the shear plate and receives the conveyer therein.

An additional section 25 of the conveyer tube may be provided of such length as required and suitably secured to the adjacent sections in order to secure the proper length of the conveyer feed means. As will be understood the distance through which the conveyer must operate from a bin to the furnace will vary in different installations, and it merely becomes necessary to provide the proper length of feed worm, making use of such length of conveyer tube as required for that purpose. The retort itself is shown at 26, and a conveyer tube 21 is suitably attached to the base 28 of the retort by means of a retaining collar 29.

In order to secure the conveyer tube 25 in feeding relation between the sections 24 and 21 a lpair of similar split clamping members are provided which as shown comprise a lower semicylindrical half 30 into which the adjacent end of the conveyer tube is fastened. The top half 3| is removably fastened to the lower half by bolts 32, thus making it possible by removing the two upper halves, to effect removal of the intermediate conveyer tube 25'. This pro-vides for withdrawal of the conveyer worm as described below.

The retort is formed with an air inlet passage 35, and with a web portion 36 which serves as a continuation of the conveyer tube through the base of the retort, the wall of the base Ipart being curved and opening upwardly as shown at 31 directly below the retort, to provide fo-r delivery of the solid fuel thereinto. The fuel is delivered upwardly in regulated and uniformly distributed manner between the upwardly curving walls 38 of the retort.

A second worm shaft 4I] extends through the retort, and into the tube 21 adjacent the end of the shaft I2. Shaft 4l) is likewise formed with a conveying flight 4I thereon for feeding the fuel forwardly through the tube for delivery into a position beneath the retort 26. In order to provide for the driving of shaft I2 and the relative shifting thereof with respect to shaft 4i), a universal driving connection is provided between the adjacent ends of the Worm shafts I2 and 46. This member is shown at 42 as comprising a central hub portion of substantially the same diameter as that of the two worm shafts. At each end the hub is formed with a groove 43 adapted to receive a cooperating tongue on the end of the adjacent conveyer shaft, the two grooves in the ends of the member 42 extending at right angles with respect to leach other. Bolts 44 are threaded into member 42 and pass through the tongues 45 formed upon the end of the shafts, respectively, each tongue and shaft being thus adapted to pivot with respect to hub 42 about the axis of the re- Slpective bolts, The hub portion 42 is likewise `provided with a spirally curved portion 46 which isconstructed to function as a continuation of the night on the adjacent ends of the conveyers,

'being formed as shown to cover substantially three-.fourths of a revolution and to line up directly with the nightportions on each of the conveyor shafts. As will be clear from the drawing and from the above description, there is practically no change in the effective conveying area of the tube as a result of the provision of such universal joint and the conveying action of the worm is thus made to progress continuously and uniformly substantially without interruption.

It may become necessary during the operation of the stoker to remove the c-onveying worm from the bin for repair or replacement, and the construction of the present invention provides for such operation in a simple manner` and without the necessity of removing the solid fuel within the lbin. To remove the worm, the two upper clamping members are removed, affording access to the universal joint. Upon removal of the Ibolts therefrom, the entire intermediate conveyer tube and the worm shaft may be withdrawn from the bin, the shaft being rotated if desired to avoid as much as possible the drawing of fuel out of the bin. To replace the same, the shaft is merely guided into position by the trough 25, meanwhile being rotated to cause the worm to thread its way into the fuel. nnal position and the two sections of the worm coupled together.

At the side of the retort opposite that through which the solid fuel is delivered there is provided an additional tube l) which is mounted upon the I end of the retort by means of a collar 5| in axial alignment with tube 2i and with surface 36, in position to receive the extending end of conveyer shaft 43. A reverse flight 52 is formed upon this portion of shaft 46, of such character as to prevent the delivery and passage of fuel into the tube 50, which is thus kept substantially Aclear and free of fuel during the operation of the device. In order to provide for the proper feeding of the fuel upwardly into the retort in uniformly distributed manner, and to avoid unnecessary churning thereofbeneath the retort, the forward night El and the reverse night 52 terminate in dennite spaced relation to the other, to the wails denning the opening in the retort and preferably in predetermined angular relationship. With retorts of larger dimensions such as those for example for burning up to 350 pounds of fuel per hour and greater, it is found that the reverse night should not extend substantially beyond the projected wall of the retort, as otherwise the uniform supply of fuel to that side of the retort is impaired. The forward feeding flight should extend into the retort a distance approximately between one-third and one-half of the length of the retort, to secure uniformity in delivery of the fuel. The same general relations apply to retorts of smaller capacity, and with such smaller sized retorts capable of burning for example up to about pounds of fuel per hour, such relationship will result in the adjacent ends of the forward and reverse flights terminating in such relation as te be spaced apart by a distance varying from approximately once the pitch of the flights to half the pitch of the nights. With such relationship, as shown in the drawing, very satisfactory delivery of fuel upwardly in uniformly distributed manner into the retort is secured with substantial reduction or elimination of objectionable crushing and churning of the fuel beneath The tube is then clamped into the nights and upon the wall 36 of the retort. Further in order to secure satisfactory delivery of the fuel without churning it has been found desirable to arrange the end of the reverse flight in predetermined phase relation with respect to the end of the forward night so as to lead the latter by approximately a quarter revolution. In the arrangement shown the forward night 4i terminates with respect to the end of the reverse night 52 at a distance approximately half of the pitch of the nights, and lagging the reverse night by approximately a quarter of a revolution.

The driving means for operating the conveyer is carried by a supporting casting iii) against which the end of tube bilis fastened by means of a retaining collar Si. A motor bracket E2 is mounted upon upwardly projecting portions of the casting 6G and the drive motor S3 is arranged to drive a reduction gear device f through a drive belt 65. The reduction gear device is formed with a projecting driving shaft 66 which is of non-circular cross section, and adapted to be removably received in driving relation with a similarly formed end collar nl integrally formed with a connecting member Member 6E is journalled within the supporting member Gil as shown at 69, and a thrust bearing 'lil provides for properly taking of the thrust of the shaft through collar 6l. Suitable means comprising a washer 'H and a retaining collar i2 provided over the end of the connecting member G3 serve to prevent the access of fuel, dust, and the like into bearing 69.

The end of the connecting member 68 projects into the tube 59 and is there provided with a pivotal connection 'I3 with the end of a connecting shaft 14, shaft 14 being thus positively rotated by the connecting member and being capable of angular adjustment with respect thereto. Shaft 14 is pivotally connected at its opposite end with a hub 15 formed upon shaft 4B, and thereby serves to transmit the driving force from the connecting member into the worm The construction provides for flexibility in the arrange ment and application of the device to different installations, inasmuch as the driving assembly including the connecting member S8 may be constructed as a unitary device and of standard dimensions, and the proper adjustment made in each case to nt the installation by appropriately changing the length of tube 5B and of shaft 14, such adjustment being very readily made and simply carried out.

The invention therefore provides a highly satisfactory, simple, and light weight, and economical stoker device for use in feeding solid fuel directly from a bin into a retort for combustion therein. The device provides for such fuel delivery in a predetermined desired quantity and under such controlled conditions that not only is the power required kept within a minimum, but

` the fuel is delivered in the desired form, and withshaft having conveyor nights thereon extending into said bin, a nat-walled V-shaped trough positioned beneath said shaft where exposed in the bin, means for rotatably supporting one end of said Worm shaft Within said bin by contact of the flights thereof upon the walls of said trough and providing for free Withdrawal and replacement of the shaft along the length of said trough, a conveyer tube extending away from said bin and receiving the other end of said worm shaft, a second worm shaft Within said tube also having a conveyor night thereon, and a universal joint normally connecting said two worm shafts in driving relation With each other, said universal joint providing for relative shifting in the axial alignment of said two shafts during rotation thereof and also providing for disconnecting said worm shafts to permit withdrawal and replacev ment of said nrst shaft, said universal joint being formed with a central portion not substantially larger in diameter than said shafts and having a portion of a night formed thereon joining and in regular continuation of the nights on said worm shafts to normally effect continuous feeding of said fuel while avoiding packing and crushing of the fuel at said joint.

2. A stoker of the character described adapted to feed solid fuel from a bin and having a conveyer member removable from and replaceable in the loaded bin comprising a worm shaft extending into said bin and having conveying nights thereon, the face of said nights being of uniformly tapering width increasing toward the discharge end thereof, a nat walled substantially V shaped trough beneath and in direct supporting relation to said flights at spaced points above the bottom of the trough and below and on opposite sides of the axis of said shaft, said trough sloping downwardly toward the discharge end of the bin and said slope corresponding with the increase in width of said nights to provide continuous support along the length of the nights with the axis of the worm shaft maintained substantially horizontal, and means located beyond the discharge end of the bin for driving said worm shaft.

3. A stoker of the character described adapted to feed solid fuel from a bin and having a conveyer member removable from and replaceable in the loaded bin comprising a worm shaft -extending into said bin and having conveying nights thereon, the face of said nights being of uniformly tapering width increasing toward the discharge end thereof, a substantially V shaped trough beneath and in direct supporting relation to said nights, the trough being denned by plane surfaces in direct Contact with said nights at spaced points above the bottom of the trough and on the opposite faces of the nights, said trough sloping downwardly toward the discharge end of the bin to provide continuous support for the tapering night to support the same With the worm axis located and supported in a substantially straight line.

4. A Stoker of the character described adapted to feed solid fuel from a bin and having a con- Veyer member removable from and replaceable in the loaded bin comprising a worm shaft extending into said bin and having conveying nights thereon, the face of said nights being of uniformly tapering Width increasing toward the discharge end thereof, a substantially V shaped trough beneath and in direct supporting relation to said nights, said nights contacting the opposite sides of said trough at spaced points above the bottom of the trough, the trough being denned by intersecting plane surfaces and sloping downwardly toward the discharge end of the bin to provide continuous support for the tapering night to support the same with the Worm axis located and supported in a substantially straight line, and means for rotatably supporting the end of the Worm located at the innermost part of the bin.

5. A Stoker of the character described adapted to feed solid fuel from a bin and having a conveyer member removable from and replaceable in the loaded bin comprising a Worm shaft extending into said bin and having conveying nights thereon, the face of said nights being of uniformly tapering width increasing toward the discharge end thereof, a substantially V shaped trough beneath and in direct supporting relation to said nights, the trough being donned by intersecting plane surfaces and sloping downwardly toward the discharge end of the bin to provide continuous support for the tapering night at spaced points below and on opposite sides of the axis of said shaft to support the same with the worm axis located and supported in a substantially straight line, and a cylindrical conveyer tube extending in continuation of said straight line and communicating with the discharge end of said worm, the Width of face of the nights extending into said cylindrical conveyer tube being greater than that of the greatest diameter of the worm nights in the bin.

CLARK SCHOLL.

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