US2376502A - Apparatus for dehydrating - Google Patents

Description

May22, 1945. OVERTON 2,376,502

APPARATUS FOR DEHYDRATING Filed Oct. 21, 1942 4 l4 ZIWEETEI' 62.6w Oyzray.

Patented May 22, 1945 APPARATUS FOR DEHYDBATING Glen Overton, Dowaglac, Micl1., assignor to Louisville Drying Machinery Company, a corporation of Kentucky Application October 21, 1942, Serial No. 482,805

drum becomes over-cooked and, particularly if it Claims.

This invention relates to an improved apparatus for dehydrating and is directed more particularly to such apparatus as are utilized for the removal of films of dehydrated refuse from drum drier machines, or the like.

The assembly shown herein is well adapted for use on drum drying apparatus of the character 7 having a drier drum adapted to receive a film of material to be dried and a scraper assembly mounted in the path of vapors rising from the drum surface.

One of the difilculties encountered in the use of drum drying apparatus is that the efficiency thereof, so far as the volume of film dried in a given period of time is concerned, is detrimenhas a sugar content, becomes sticky thus 'detracting from subsequent emcient operation of the scraper blade.

To the end that the above disadvantages may be overcome, and in order that the dehydrating apparatus may be operated with maximum efdciency, there is provided herein an improved scraper blade holder assembly which is so constructed that condensation of vapors thereon is eliminated and the position of the holder and the blade as originally set, is maintained securely.

Still another object of this invention is to so heat the blade holder that the portion thereof tally eflected when the film is not readily removed from the drum and when this removed film is not readily discharged from the point of removal.

The important factors which contribute to or detract from the efilcient operation of the drum and thus to'the volume of film which it is capable of handling are the efiiciency of the action of the scraper blade upon the drum and the efilciency of the dehydrating action whereby the film will be dried to such a degree that it will easily and quickly traverse the receiving apron leading to a suitable conveyor mechanism. The unison of these two factors culminate in a device which handles a maximum quantity of film in a given period of time.

- It has been found in the past that the output of a drum drier is considerably reduced in the event that the film is not discharged from the point of removal from the drum in a condition of maximum dryness. It has further been found that when the drum is first heated at the start ofthe drying operation, the atmospheric moisture which is inevitable in the vicinity of the apparatus condenses upon certain parts thereof which are heated only by radiation from the drum and thus attain the desired elevated temperatures very slowly. This condensate which collects on these slowly heated parts, particularly the heavy metal blade holder, flows onto the dried film which is first discharged from the drum with the result that the latter again becomes soggy, will not pass easily over the discharge apron and thus collects on the apron and causes a dela in the operation of the apparatus generally. This delay is further augmented in the event that the scraper blade is not maintained which is nearest to the dried film and which depends directly over the film has the heating medium applied directly thereto whereby any condensate which happens to collect on the upper portion thereof must pass over the directly heated, depending portion and be there vaporized to prevent dripping onto the dried film.

v an improved mounting structure for a blade holdin a desired set position which is so calibrated Still another object of this invention is to pro-- vide a blade holder asembly with an upper massive portion and a lower portion which is constructed and arranged to be heated to an ele-' ing on the latter will be vaporized on the lower portion to prevent dripping therefrom.

A further object of my invention is to provide er whereby any wear between the holder memher and the mounting member is taken up by adjustment so that the blade is at all times maintained rigidly in a predetermined position.

In accordance with the general features of my invention there is provided herein a scraper blade holder assembly in which there is formed a duct for receiving a heating medium such as steam or the like whereby the blade and the blade holder may be heated to an elevated temperature independently of the heat radiated thereto from the dehydrating drum, and wherein there is provided positive locking means for maintaining the holder together with the scraper blade securely in position whereby it continues to efficiently remove driedfilm completely from the dehydrating drum throughout prolonged. periods of operation. v

Still another object of my invention is: to provide an improved method of preventing condensed moisture from dripping onto dried film as it is discharged from the drum surface.

Many other objects and advantages of my invention will become apparent from the following description and accompanying drawing, in which:

Figure 1 represents a fragmentary side eleva- I shown herein is for illustrative purposes only and may be changed and varied without departing from the spirit and scope of the invention as set forth in the appended claims.

Referring to the drawing, and particularly to Figure 1, supporting end frames l and II support the ends of a mounting rod i2 upon which the scraper blade holder I3 is rotatably mounted.

A dehydrating drum II is rotatably mounted in I any suitable manner, not shown herein, to carry a film l5 which is dried upon the drum and is removed therefrom by a scraper blade l6 whereupon it is bent backwardly upon itself and discharged onto an apron H from whence it passes to a suitable conveyor, not shown herein.

As best shown in Figure 1, the blade holder i3 is elongated to extend across the drum to support the blade l8 which has a length equal to or preferably slightly larger than the width of the drum.

As will be seen from Figure 2, the holder l3 includes a rounded head or upper portion l8 which is bored as at IS, the diameter of this bore being somewhat larger than the radius of the mounting rod I2.

Fitted into each end of the bore i9, as shown at the left of Figure 1, is a bushing which is press fitted tightly against the wall of the bore. The inner surface of each of the bushings 20 is adapted to receive the outer surface of the mounting rod i2 with a tight friction fit so that 'the blade holder l3, together with the bushing,

may be rotated around the mounting rod l2.

To the end that the blade holder l3 may be adjusted at the desired angle, so that the blade i6 may be rigidly positioned to most efficiently remove the film i5 from the drum ll, each of the bushings 20 is cut out as shown at 2i in Figures 3 and 4. Inserted in each of the cut out "portions 2| is a, shoe member 22 which has an inner face conformed to the configuration of the outer wall of the mounting rod l2 and which is seated in a recess 23 formed in the inner wall of the bore IS. The head i8 of the blade holder I3 is drilled and tapped at each end at a point in alignment with the lower end of the respective shoes 22 and adjusting screws 24 are inserted therein. Rotation of the screws 24 will urge the respective shoes against the wall of the mounting member l2 thus to lock the blade holder and the bushing 20 on. the mounting rod l2 against rotation relative thereto. Furthermore, it will be seen that should the bushings 20 become worn the slack created will be taken upby the pressure of shoes 22 and 24 with the result that the blade is prevented from vibrating into and out of the predetermined, adjusted position. Depending from and integral with the hea portion l8 of the blade holder assembly is a blade holding element 25 which is suitably recessed at the lower extremity of its under surasmsoa face to receive the blade li. A blade holding strip 26 is releasably secured to the under surface of the blade holding portion 25 bymeans of screws 21 and is adapted to extend over the 5 blade receiving recess thereby to engage the blade and hold it is position when the screws 21 are screwed tightly into the blade holding portion 25.

From the foregoing it will be seen that the operator by releasing the screws 24, may adjust the angle of the blade holder assembly, together with the blade, whereby the proper relationship between the cutting tip of the blade and the surface of the drum H may be easily and quickly established. Thereafter, it is merely necessary to tighten the screws 24 and urge the inner surface of the shoes 2| against the surface of the mounting rod l2 in order that theentire blade holding assembly be locked precisely in the exact position to which it has been regulated by the operator.

As seen most clearly in Figure 2 the blade holding portion 25 of the blade holder assembly It depends substantially over the surface of the drum i4, and over the film i5, as it is removed from the surface of the drum. As the film is picked up by and formed on the surface of the drum it is moist, and the drum, being heated, will vaporize moisture from the film to cause the atmosphere surrounding the apparatus to become extremely humid. Under these circumstances, condensation will occur on all objects, especially the metallic objects of the apparatus, which have not as yet become heated. From Figures 2 and 3 it will be seen that the blade holding portion 25 of the blade holder assembly I3 is of extremely heavy construction and thus the metal thereof does not become heated'to the desired elevated temperatures by radiation from the drum until the apparatus has been in operation 40 for some considerable period of time.

' It will be readily understood that until the blade holder assembly becomes heated considerable condensate is deposited thereon and that as this condensate accumulates it drips down by I. gravity to the tip of the knife where it passes the dried film to again wet it. This condition,

as previously indicated, substantially nullifies' the drying effect which has been produced from the heat of the drum l4 and furthermore makes the film tacky, so that discharge thereof over' the apron I! is very detrimentally affected.

To the end that the blade holding assembly may be heated to elevated temperatures in a period comparable to the short period which is required to heat the drum it, there is provided in the blade holding portion 25 a duct 28 having an inlet 29 and an outlet 30. 'This duct is closed at either end, except for the inlet and the outlet, in any suitable manner, as by inserts 3| and 32, and is adapted to receive steam, hot air, or any other suitable'heating medium through the inlet 29, this medium being discharged through the outlet 30. When it is desired to commission the apparatus for use, the drum heating system is turned on and the heating medium is discharged through the duct 28 whereupon the respective asvasoa maintain its adjusted position in relation t me surface of the drum ll. This is accomplished not only by means of the adjustable shoes 22 as hereinbefore described, but also by the considerable weight of the blade holder assembly l3 and particularly the depending blade holding portion I! thereof.' It has been found that the greater the mass of the blade holding assembly, the greater the resistance thereof to accidental or incidental 'rotative'movement about the mounting rod H.

To the end that'the depending blade holding portion "may be heated as above explained, and in order that the mass 'of the blade holding assembly it, particularly the portion 25 thereof, is

j. notreduced to too great a degree; the-cavity or a duct 28, as will be seen most clearly from Figure 2,

has a cross sectional area considerably less than that of the blade holding portion 25. Thus con-r 3 sired elevated temperature simultaneously with the heating of the drum. when the dehydrating V apparatus is started up, these thinner, heated porsiderable metal is retained in the blade holding portion and the weight thereof imparts the desired quality to the assembly.

It will be seen that the'cavity or duct 23 is so disposed in the blade holding portion 25 that thinwalls 33 extend over substantially the lower blade holding portion. With such a construction it has been found that the upper section of the blade holding portion 25 is heated to the desired elevated temperature only after a prolonged period of time because of its considerable mass while the lower portion thereof, being composed of the thin walls 33 and the blade l6, become heated ina period of time commensurate with that required for heating of the drum I4. Since the wall portions of reduced thickness are at the lower end of the depending blade holding portion 28 it will be readily understood that if by chance condensate should form on the head it of .the blade holder l3, that condensate in gravitating toward the film l5 mustfirst pass over the thin, readily heated wall portion with the result that it will be again vaporized, whereby dripping onto the dry film l5 will be prevente In the event that fine precision adjustments of the blade i6 over the surface of the drum II are desired, the lower end of the blade holding portion 25 may be tapped to receive adjustment screws 34, which may be driven into engagement with the adjacent surface of the blade l6 merely by rotating the heads thereof.

From the foregoing it will be seen that I have provided a scraper blade holder which has the desired mass and yet which is provided with relatively thin, readily heated wall portions at the lower edge thereof whereby the lower edge portion and the blade are both heated to the desired elevated temperature in aperiod of time com- .mensurate with that period requiired'to heat the associated drum. Furthermore, the'disposition of the thinner walls 33 at the lower edge of the holder assembly further insures against condensate dripping therefrom to reachthe dried film l5.

As previously stated, the diiiiculty encountered with the dripping of condensate upon the dried film has been experienced primarily when the dehydrating apparatus is first started up. At this time it is usually found that the various parts of the dehydrating apparatus, except for the drum proper, are cool or cold. With the present construction'the operator turns on the heating system of the drum l4 and at the same time opens the valve to admit the heating medium, such as steam, to the inlet 29 of the duct 28. Since the blade l8 and the walls 33 (see Figure 2) are relatively thin, these parts can be heated to the deblade,means for mounting said holder and said tions of the blade holder assembly prevent the dripping of condensate upon the dry film. After the apparatus has. been in operation for a period of time the heat radiated from the drum M will cause the entire blade holder assembly to become hot, whereby the diiiiculties attending condensation no longer exist. reached the operator may shut off the steam discharge to the blade holder assembly duct 23.

It will be understood thatwhile the chamber or duct 28 is shown herein as receiving heating fluid, it may be utilized to house an electrical heating coil, or the like, as the heating medium.

I claim as my invention:

1. In an assembly for removing dried film from a drum drier mountedfor rotation between end frame members, a scraper blade, a holder for said blade for movement toward and away from said drum surface including a hollow portion in said holder and a mounting rod arranged to extend between said end frame members and through said hollow portion to support the holder for rotation relative thereto and a bushing in said hollow portion receiving said rod and having an opening in its wall, and means forreleasably looking said holder against rotation relative to said mounting rod including a shoe member partially disposed in the wall of said hollow portion and extending through said opening of the bushing and means in said wall aligned with said shoe member for urging the shoe member into tight abutment against the surface of said mounting rod.

2.- In a scraper assembly for a drum drier, a scraper blade, 2. blade holder member having a hollow portion, a bushing in said hollow portion, a mounting member arranged to extend through said hollow portion and disposed in the bushing to rotatably support said holder member, a shoe disposed in the wall of said bushing and against the wall of said hollow portion and having one face thereof disposed toward the surface of said mounting member and means in the wall of the hollow portion radially aligned with the shoe for urging said shoe toward the surface of said mounting member to releasably lock the blade and holder member in a predetermined position relative to the surface of the drum.

v 3. In a scraper assembly for a,drum drier, a-

scraper blade, a holder member for said blade having a hollow portion, a mounting member arranged to extend through said hollow portion, spaced bushings press fitted into said hollow member for receiving said supporting member in rotative relationship, said bushings being partially cut away cross sectionally, shoe members slidably disposed in said cut away portions and means for urging said shoe members into abutment with the surface of said mounting member to releasably lock said holder in a predetermined position relative thereto and to take up slack due to wear. between the mounting member and said hollow portion.

4. In a drum drier apparatus, a'scraper blade holder of relatively heavy, slow-heating construc. tion disposed in the path of vapors generated by the drier apparatus and having a blade holding portion, means for securing the blade at theedge of said holder and quick heating means for-the blade and the portion of the holder receiving the same including a relatively thin wall at the edge When this condition is of the holder, said'wall encompassing a heating chamber within said holder adapted to receive a heating medium for heating the thin wall in ad- Vance o! the remainder of the holder.

5. In a scraper blade assembly for a. drum drier, a blade holder disposed in the pathot vapors generated by the drier, said holder includingva relatively massive, slow-heating portion, and an in-

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