US 2034860 A
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Description (OCR text may contain errors)
D. DALIN March 24, 1936,
DRIER Filed Dec. 1o 1954 s sheets-Sheet 1 All] lEnnN.
D. DALIN March 24, 1936.4
DRIER Filed Dec. l0, 1954 3 Sheets-Sheet 2 Mrch 24, 1936.
D. DALIN 3 Sheets-Sheet 3 eenetef-2t1e PATENTOFFICE l Dama `David Dalin, Milwaukee,.Wis. Applicants December 1o, '1934, serial No. 'isaiasi 12 claimt. totem-s2) This invention Arelates to improvements in ,driers and refers more particularly to` vacuum driers suitab'e for drying' grain, malt, vegetables and other similar materials.
l'Ihe typepf drier to which this invention is particularlyapplicable, in its general aspects' comprises a container for the material to be dried, `usually in the form `of a cylinder or' drum mounted for rotation or oscillation. Suitable means are provided for maintaining a high vacuum within the container so as to draw oi the gases from the material being dried, and in general promote the drying process.
To eiect the drying, `it is necessary to supply heat to the drier and-heretofore thisohas been done mostgeneralLv by injecting steam into a radiator structure or heat exchanger disposed within the container and with which the material being dried contacted Vas the container was revolved or oscillated. y
rlhe radiator structure in its simplest form consisted of tubes extending substantially throughout the length of the drum and communieating with a header to which the steam supply was connected.
This past construction made no provision for circulation of thel heating medium. The steaml or other heating medium` used was injected into the radiator structure, but as the tubes comprising the radiator or heat exchange unit were dead ended, each tube had a dead air space in which the air did not mix with the steam, and as a consequence, much valuableheating surface was lost.
Attempts were made to overcome this deficiency A of past'drier constructions by the'provision of pet cocks to relieve the trapped air from the tubeabut obviously this was an expensive requires ment and at best was but a makeshift arrangement. The constant attention which it required defeated its pllI'POSe. i g
With this objection to past driers in mind, it is an object of this invention to improve the construction oi driers of this nature so as to insure circulation of the heating medium and entirely obviate dead air-spaces or uneven heating of the material being dried.
More specifically it is an objectof this invenn tion to provide adrier construction Wherein the heating medium enters the drier at one end and is directly conducted to a bulkhead located at the opposite endthrough which theeheating medium is distributed to the various tubes or passages of the heat exchanger to be conducted through the body 'ot the drying material and exhausted from the same end o f the apparatus at which it enters. s.
Another object of this invention is to promote the circulation of a heating medium through the heat exchanger by maintaining a suction on` the 6. discharge of the heat exchanger.
Another object of this invention is to provide novel means for withdrawing the condensate of the heating medium from the apparatus.
Another object of this invention is to provide lll a novel shelf arrangement within the container on ,which the materialheing dried is supported and tumbled or turned as the unit revolves or oscllates back and forth.v
A further object of this invention is to utilize 15. the tubes or individual elements of the heatexchanger or radiator to provide shelves on which the drying material rests.
Still another object of this invention is to so dispose the individual elements comprising the 20 shelves that while the material being dried is in a moist condition as at the start of the drying rocess, the material will slide back and forth across the shelves and be tumbled in its movement and after the drying process has progressed sum- 2li ciently, .the material will drop through the shelves to avoiddamage to the material which might result from causing it to slide or fall thej full width of the container drum. y
With the above and other objects in view which' 30y will appear as the description proceeds, this .in-1 vention resides in the novel construction, coin-I bination and arrangement ofparts substantially as hereinafter described 'and more particularly defined by the appended claims. it being under- 35 stood that such changes in the preciseembodiment of the hereindisclosed invention may be made as come within the lscope ottlieiclaims.
The accompanying drawings illustrate' -one complete example of the physical embodiment oi wf the invention constructed according to the best mode so far devised for the practical application oi the principles thereof, and in which:
Figure 1 is a view in side elevation with parts broken away and in section of a drying unit'em- 45 bodying this invention;
Figure 2 is a cross section view taken through Figure 1 on the plane 'of the line 2 2; l
Figure 3 is a view similar to Figure 2 but showing the drum turned to another position; -50
Figure 4 is a longitudinal section view through a portion of the apparatus taken on the plane of thedine iofy Figure 1;
Figure 5 is a cross section view taken through l on the plane of the line iii-E;
'manganeumedcetmseeuonview taklenmntheplane of the line C-Cofl'igure an A Flgure'lisanenlarged section view illustrating l a detail oi the drum construction.
Referring now more particularly to the accompanying drawings in which like numerals indicate like .parts throughout the several views, the numeral 5 represents vgenerally the drum-like container of the drying apparatus which is revolubly mounted in any suitable manner, as by rollers 3 tracking on rings 1 encircling the drum as shown.
Oneoiftherings1 hasaring gear tattached to itdwith which a driving pinion 9 meshes to oscillate the entire structure through a predetermined number of degrees. The specinc manv ner in which the pinion 8 is driven and its direction of rotation is changed forms no part of 20 this invention, and fis. therefore, not shown. A
The drum 5 comprises an outer casing Il and an inner concentric shell Il with a space I2 therebetween through which the heating medium circulates as will be hereinafter more fully described.
'I'he inner shell II is shorter than the outer casingand is closed at one end by a header plate I3 spaced i'rom the adjacent end I4 of the casing.
and at itsother end by a .fhollow bulkhead I5 3 likewise spaced from the adjacent end I8 oi.' the casing.
'Ihe proper spacing betweenV the shell and casingismaintained bytherings 1 which, as best shown in Figure 7, extend into the casing and 85 have the drum reaped ends u and le of the casing as well as its medial cylindrical body portion welded thereto. The adjacent peripheral prtlons o! the inner shell are also welded to the rings. c
The ring 1 adjacent the header plate I3 has a plurality of openings I1 which communicate the Acylindrical space I2 encircling the shell II with /the compartment I8 provided by the inside oi' the cuppedend I4.
At the opposite end. oi' the shell, the cylindrical space I2 is'communicated with the interior of the hollow bulkhead I5 through a plurality of openings I9 in the cylindrical wall of the shell. To accommodate -this latter communication between 50 the cylindrical space I2 and the interior of the hollow bulkhead, the inner wall 2l of the hollow bulkhead has its peripheral portion 2I directedinwardly as shown. The outer wall 22 oi' the hollow bulkhead I5 has its periphery tightly iixed 55 to the adjacent end of the shell II.
The compartment I8 is thus communicated Vwith the interior of the hollow bulkhead I5 through the cylindrical space I2 encircling the shell. Further communication between these chambers or spaces is aiIorded by a plurality of tubes 23 in the nature of boiler tubes havi g one end iixed in holes in the header plate`^ 3 and their opposite ends fixed in holes in the inner 65 wall 20er the hollow bulkhead. These tubes 23,
together with the space I2, provide the heat exchanger or radiator for heating the material Within the shell Il. For charging and discharging the drier, an
70 opening 24 is provided. The opening 24 is defined by a short cylinder passing through and welded to the peripheries of holes in the inner shell and the outer casing. A removable cover 25 normally closes the' opening.v If desired, a separate dis- 75 charge opening may be provided, but ordinarily the one opening 24 is suiilcient both for charging and discharging the drier.
The heating medium most generally used is steam, and in the present embodiment, it circulates continuously through the heat exchanger or radiator structure so as to insure uniform heat distribution.
To conduct the steam into the heat exchanger or radiator structure, a steam line 21 having'a cohtrolllng valve 28 passes through the compartment I8 to be connected to a supply tube 28 at the header plate I3. The connection 30 between the steam line 21 and the tube 29 is illustrated in detail in Figure 6. As here shown, the tube 29 is rigidly secured to the header plate I3 and the adjacent end of the steam line 21 has a freely rotatable, but fluid tight connection with the header plate in axial alignment with the tube 29. I
Any suitable construction may be used at this point and in the present instance, a flange 3| is welded to the outer face of the header plate to rotatably receive the adjacent end of the steam line with a packing ring 32 between the steam line and the iiange to provide a uid tight seal therebetween.
' The tube 29 divides into two branches directly inwardly of the header platekas best shown in Figure 4 and lthe ends of these two branches are secured to the inner wail 2l of the hollow bulkand the cylindrical space I2 surrounding the L shell to move forwardly into the compartment I8. Communicated with the compartment I3 is a hollow stationary trunnion 34 which encloses the steam line 21. 'I'he trunnion 34 is journalled in a collar 35 iixed to the adjacent end I4 of the casing in open communication with the compartment I8. The juncture between the hollow trunnion 34 and the sleeve 35 is made iiuid tight by a packing gland 36.
Connected to the hollow trunnion 34 is an exhaust pipe 31 which leads -to a steam trap B. The condensate outletv ofthe trap is connected with a waten pump W which constantly draws off the accumulated condensate, and the air outlet of the trap is connected with a vacuum pump V whereby a subpressure is maintained in the hollow trunnion 34 and consequently in the chamber I8. Circulation of the heatingk medium through the drier just as fast as condensation occurs is thus assured and dead`- air spaces are completely precluded.
The condensate is conducted to the hollow trimnion 34 by a trough-like extension 38 projecting therefrom into thecompartment 4I8 in which the condensate accumulates, as now about to be described.
Dividing the compartment I8 into two semicircular chambers 39 and 40 are two radial Walls 4I and 42. The walls 4I and 42 are in line and terminate short of the center of the unit where each connects respectively with two angularly Adisposed walls 43 and 44.
As clearly shown in Figures 2 and 3, the angularly disposed walls 43 and 44 substantially surround the trough-like extension 38 of the hollow trunnion and as the drier revolves. or oscillates back and forth, first one set of angularly disposed walls and then the other is disposed above the open top of the trough 48.
At their inner extremities, the angularly disaccesso posed walls have elongated openings 45 and turned up flanges 46 so that condensate accumulating within the chambers 39 and 40 and running down the sides of the walls 4I and 42 and over the angularly disposed walls 43 or 44 during oscillation of the apparatus, runs through the openings 45 into the-trough 38.`
Inasmuch as the oscillation of the unit issuicient to carry ilrst one and then theother set of angularly disposed walls over the open top of the trough, the manner in which the chambers 39 and 40 are drained of condensate will be readily apparent. i
While the invention thus far described, through the provision of assured circulation of the heating medium greatly improves the operation of driers in general, it 'has particular application to the vacuum type of drier in which the drying compartment is substantially evacuated. For this purpose, screened openings throughthe hollow bulkhead l5 communicate the interior of the inner shell with the space or compartment 5i defined by the cup shaped end I6.
The end wall I6 has a nozzle or .nipple 52 fixed thereto to which a suction pipe 53' is attached. To allow for oscillation of the drying unit and obviate' the necessity for a packed joint between the suction line and the nozzle or nipple 52, the suction line is in the form of a rubber hose, as shown and described in Patent No. 1,561,166.
To aiord access to the compartments i8 vand 5|, the ends I4 and I64 may be provided with openings having removable covers S3.
Attention is now specically directed to the arrangement of the tubes 23 which together with the cylindrical space I2 provide for the circulation of the heating medium. IAs shown in Figures 2 and 3, these tubes are arranged in two sets A and B on opposite sides of a planepassing through the unit in linewith the partition walls 4| and 42.
The tubes of each set are arranged in tiers or shelves spaced one above the other and inclined `slightly from the center to theoutside when the drum is in an intermediate position, shown in Figure 2'. 'I'his inclined arrangement of the tubes facilitates discharging the drier, for when the drum is in its discharging position with the opening 24' lowermost, the downward inclination of the shelves will-promote more rapid discharge.
The-tubes comprising each shelf or tier are so located with respect to each other that when the green material is first deposited into the drying compartment, it is prevented by its inherent nature from dropping through the spaces between the tubes, so that as the drum is oscillated back and forth, the material is rolledirom one shelf to another and tumbled as it moves, thus continuously turningL the material and insulting uniform drying.
As the material dries, "it becomes bri and especially in the case of malt, it is very undesirable at Vthis stage to throw the material from one.
'than be tumbled across thehshelves and from one side of the shell `to the other. In this manner,
the desired turning of the material is effected without the danger of injuring the material after -it becomes brittle.-
From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art to which this invention appertains, that the con-fl struction of driers for malt, grains, vegetables and. the like has been greatly improved thereby, particularly through the provision of means for insuring circulation of the heating medium and through the provision of novel means for agitating or turning the material during the drying process.y
What I claim as my invention is:
1. In a drier of`\the character described, a rotatable casing having an end wall, a partition wallwithin-the container spaced `from said end wall to cooperate therewith in defining a closed end compartme t, a hollow partition wall at the opposite end of he rotatable container to coop,- erate with the first mentioned partition wall in defining a material receiving compartment, a plurality of ducts communicating the interior of the hollow partition wall with the iirst mentioned compartment, an inlet for heating medium passing through said rst mentioned compartment and through the material receiving compartment forfcommunication with the hollow partition wall'.
dene a closed chamber, a hollow partition wallv cooperating with the first mentioned partition wall and other of the casing walls to dene. a material receiving compartment and cooperating with the opposite end of the casing to deiine a suction chamber, hollow heat transfer elements connecting the rst mentioned partition wall with the inner wall of the hollow partition to communicate said rst mentioned compartment with the interior of the hollow partition, means for conducting a temperature modifying medium into the interior of the hollow partition, means for withdrawing said medium from the iirst mentioned partition, said hollow partition having screened openings commiinicating the material receiving coinpartment with said suction chamber, and means connected with the suction chamber through which said suction chamber and consequently the material receiving compartment may be evacuated. V
3. In a drier of the character described, a rotatable-unit comprising a casing closed at its ends, a partition wall adjacent one closed end ofv the casing and cooperating with said end to form a closedvgcompartment, a hollow, partition wall adjaceniifthe opposite end of-'the casing cooperating wiiifsaid end to form a suction chamber and cooperating with the first mentioned partition wall to deiine a material receiving compartment, said hollow partition wall having screened openings therethrough for permitting the passage of,
gases from-the material'vreceiving compartment into the suction chamber, means through'which the suction chamber may be evacuated whereby material within the material receiving compartment may be subjected to the eiect of vacuum, a supply line vfor a heating medium, extending through the first mentioned compartment and the material recei ing compartment for communication with the nterior of the hollow partition wall, hollow heat exchanging-elements communicating the interior of the hollow partition wall with said iirst mentioned compartment, and means for exhausting spent heating medium from the ilrst mentioned compartment so that heating medium is caused to circulate through the hollow partition wall and the hollow heat exchanging elements.
4. In a drier of the character described, a casing mounted for oscillation and having an end wall, a partition within the casing forming one wall of a material receiving compartment and cooperating with said end wall to define a closed exhaust compartment, a heat exchanger within the material receiving compartment comprising hollow heat exchanging elements opening to said closed exhaust compartment, means for exhausting spentheating uid from the exhaust compartment including a hollow trunnion extending through said end wall oi' the casing, and means for withdrawing condensate from said closed exhaust compartment comprising an open topped trough Vconnected with said hollow trunnion, and baille walls within'the closed exhaust compartment for directing condensate into the open topped trough during oscillation of the unit.
5. In a drier including a casing rotatable about a xed axis and havinga partition wall dividing the casing at one end thereof into an 'exhaust compartment and a materialreceiving compartment, means for circulating a heating fluid through the material receiving compartment including hollow heat exchanger elements having open ends secured to said partition and communicating with the exhaust compartment, a stationery hollow member having a freely rotatable connection axial to the axis of rotation of the casing with an outer wall of the exhaust compartment and connected with the exhaust compartment to provide an exhaust port through which spent heating medium is exhausted from said compartment, and meansfor withdrawing 'condensate from said compartment comprising an open topped trough connected with said hollow member, and baille walls within the exhaust compartment for guiding and conducting condensate accumulating therein into the openv topped trough as the unit turns about its axis, of gyration.
6. In a drier, a rotatable drum, partitions in said drum dividing the same into end compartments and a central material receiving compartment, means i'or communicating one of the end compartments with the material receiving compartment so as to allow the extraction of gases from the material receiving compartment by suction applied to said end compartment, means communicated with said end compartment through which .suction may be applied thereto, an inlet for heating medium passing through the opposite end compartment and through the material receiving compartment for connection to the partition at said mst designated endv or th drum, said partition be hollow to receive the -heating medium, hollowv heat exchanging elements passing thrugh the material receiving compartment for communicating the interior ot the hollow partition with said opposite end compartment, and means for exhausting spent heating medium from said last named end compart- `ment, said exhausting means including an exhaust pipe connectible with a suction source so as to promote'circulation of the heating medium.
7. In a drier o! the character described, a rotatable \drum, hollow heat exchanging elements disposed longitudinally within said drum, said heat exchanging elements being arranged in two tiers at'vopposite' sides of an unrestricted space extending substantially diametrically across the inside o! the drum to provide, opposite shelves upon which materialv to be dried rests to be tumbled and turned by sliding over the shelvesof the container such material is rolled and turned to present all parts thereof to the heating surfaces provided by said tubes and as the material drys it falls through between the tubes to preclude throwing the material from one side of the container to the other.
9. In a drier, a rotatable drum adapted to contain material to be dried, a heat exchanger unit within the drum comprising a plurality of tubes arranged parallel to the axis 'oi' the drum and disposed in opposed sets of tiers on opposite sides of ya central plane extending longitudinally through the drum, said tiers of tubes providing shelves upon which the material being dried is supported to be tumbled from one shelf to another as the drum turns, said drum having a charging and discharging opening substantially in line with the central plane on opposite sides of which the sets of tiers are arranged, and said tiers of tatable drum adapted to contain material to be4 dried, a plurality of heat exchanger tubes extending longitudinally through the drum, said tubes being arranged in opposed sets of tiers with the tubes comprisingone set spaced from those comprising the other set to denne a substantial unrestricted spaceextending across the inner ends of the tiers, and with the individual tubes of each tier arranged in staggered relationship and each tier comprising at least two rows of tubes spaced apart a distance less than the diameter of the tubes but suiiicient to allow the material after it has been dried a predetermined amount to fall through the tiers.
11. In a drier of the character described, a drum rotatable about a xed axis, a partition wail within the drum cooperating with an end wall thereof to'pdefine an exhaust compartment and one end of a material receiving compartment to contain the material to be dried, a heat exchanger unit within the material receiving compartment, a supply line for conducting a heating medium to the heat exchangerunit comprising a xed section extending through an axial opening in said end wall of the drum to said partition wall and a movable section rotatable 12. In a drier of the character described, a drum rotatable about a xed axis, a partition wall adjacent one end of the drum to cooperate therewith in forming an exhaust compartment and also forming one end wall of a material receiving compartment, a heat exchanger unit within the material receiving compartment including ducts opening to the exhaust compartment, a supply line for conducting a heating medium to the heat exchanger unit comprising a xed section passing through an axial opening in said'end wall of the drum and a movable section joined to the xed section at the partition wall, and an v exhaust line including a hollow member telescoped over the xed section of the supply line and freely rotatably joined to said end wall of the drum over the opening therein so as to have direct communication with the exhaust compartment for exhausting spent heating medium therefrom.