US1783844A - Heat-transfer apparatus - Google Patents

Description

.Dec. 2, 1930 J. N. JAcoBsEN HEAT TRANSFER APPARATUS 2 Sheets-Sfieet 1 Filed March 13, 1928- D c. 2, 1930. J. N. JACOBSEN 1,783,844

' HEAT TRANSFER APPARATUS 2 Sheets-Sheet 2 Filed March 13. 1928 YVINVVENTOR 02725 [19 acassm ATTOW Patented Dec. 2, 1930 UNITED, STATES PATENT OFFICE JENB N. J'ACOBSEN, O1 ALAHEDA, CALIFORNIA, ASSIGHOR 1'0 THE PFAUDLEB 00., OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK HEAT-TRANSFER APPARATUS Application fled latch 18, 1928. Serial No. 361,348.

This invention relates to a heat transfer apparatus and has for its principal ob'ect the provision of such an apparatus whic is more satisfactory, eflicient and dependable in operation than others heretofore known.

Another object of the invention is the provisionof a heat transfer apparatus in which the material to be treated can be heated to a very high temperature or cooled to a low temperature without becoming caked on the walls of the apparatus to such an extent as to interfere seriously with the transfer of heat through the walls.

A further object of the invention is the provision of heat transfer apparatus which may be used for cooling an ice cream mixture or other similar material in which means is provided for scraping the walls of the apparatus during the operation thereof, such means preferabl consisting of a spirally or helically formed strip of material which is rotated by the movement of the fluid through the ap aratus.

To t ese and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed outv in the claims at the end of the specification.

In the drawings:

Fig. 1 is a longitudinal section taken approximately centrally through an apparatus constructed in accordance with a preferred embodiment of the invention:

Fig. 2 is a view of the cover member or door used at one end of the apparatus;

Fig. 3 is a view of the cover member or door used at the other end of the apparatus;

Fig. 4 is a transverse sectional view taken app ro 'mately on line 44 of Fig. 1; and ig. 5 is a longitudinal sectional view through the tubes used in the apparatus.

The same reference numerals refer to the same parts through the several views.

Referring now to the drawings, there is illustrated a heat transfer apparatus including a drum 11 having manifolds 12 and 13 at the ends thereof, and an outer shell member 14 surroundin the inner drum 11 and the manifolds, as i lustrated in Fig. 1. The

space between the inner drum 11 and the shell 14 is preferably filled with some suitable lagging or heat insulating material, such as as estos.

Removably mounted within the drum is a tube assembly includin tubes 16 havin their ends supported in hea ers 17 and 18, t e latter having its periphery secured to an annular flange on the manifold 13 by means of suitable bolts 19. The other header 17 is of a smaller diameter than the manifolds, so that the entire tube assembly maybe removed from the drum as a unit by unfastening the bolts 19 and drawing the tubes and headers leftwardly when viewed as in Fi 1. An annular flange-formed on the header 17 has a snug sliding fit within an internal flange 20 on t e manifold 12. A ring ofpacking material 21 surrounds the header 17 and is ressed against the manifold 12 to form a tigl it joint by means of the annular member 22 secured in place by bolts 23 threaded into the manifold 12, all as shown in Fig. 1.

This jointed arrangement between the tube assembly and the drum at the right hand end of the apparatus not only permits easy re moval of the tubes as a unit, but also provides an expansion joint so that the tubes may expand-or contract relative to the drum, without creating excessive stresses.

Cover members such as the doors 25 and 26 are placed over the headers at the right and left ends of the apparatus, these covermembers having machined surfaces in contact with machined surfaces on the headers, so that tight joints are provided without the use of gaskets. Each cover plate has a series of cavities formed therein, the cavities being so shaped that the form passageways connect- ,ing the ends 0 two adjacent tubes to each other. In this manner, all of the tubes are connected in series, so that material forced into one end of the first tube will travel through it, then back through the next tube, forward again through the next succeeding tube, and so on. Obviously the connections could be varied so that all of the tubes could be connected in multiple or parallel, or some could be in series and some in multiple or parallel. The number of tubes used, as well as the manner in which they are connected, would depend on. the kind of material to be treated in the apparatus, and the extent to which the material was to be cooled or heated.

The cover members and 26 may be hinged to the headers 17 and 18 if desired, and may be provided with latches for bolding them in place. Preferably they are secured in position also by pivoted bolts 27 mounted on the headers, these bolts having nuts which press against split lugs 29 on the cover members.

One of the cover members,.such as 25, has threaded openings 30 and 31 extending therethrough, into which pipes 32 and 33 may be screwed. One of these pipes is connected to a source of supply of material to be treated, this source preferably including means for forcing the material into the tubes with sufficient pressure so that it will pass through the tubes and out of the other pipe. The material to be treated may be gaseous, liquid. scmiliquid, or of any form sufiiciently plastic to pass through the tubes when under pressure. The term fluid, as used in this specification and in the accompanying claims, is used in its generic sense, and is intended to include any materials of the kind above mentioned.

Suitable connections are provided for cir culating a treating medium around the tubes 16 within the drum 11. Such connections may comprise an inlet pipe 35 leading to the manifold 12. The treating medium (for example, water) enters the manifold through this pipe 35. and passes thence through the oblique slots 36 into the drum 11. The angular arrangement of these entrance slots gives the treating medium a rotating or swirling movement within the drum, thus thoroughly agitating the medium and bring in various parts of it into contact with the tu cs 16, so that the transfer of heat is expedited.

'lhc treating medium may then pass out of the drum through the slots 37 in the manifold 13, and may leave this manifold by way of a pipe 38. The exit slots 37 may be oblique, like the slots 86. the obliquity being either in the same direction as or in the opposite direction to that of the slots or they may ri xtend radially through the wall of the maniold.

It will be understood that the treating medium circulated within the drum 11 may be a gas, liquid, or semi-liquid, the mention of water being simply by way of example. W hen a liquid medium is used. air is apt to collect at the top of the drum, and a vent connection is therefore provided to remove it, this connection comprising a pi )e 40 leading from the top of the drum to the exit pipe 38, as shown in Fig. 1. A drain pipe l1 may also be provided at the bottom of the drum 11, this drain pipe being controlled by a valve 42.

The apparatus above described is fairly satisfactory for use at moderate temperatures. It is found in practice, however, that if such an apparatus be used to raise a material to a rather high temperature, the material being treated has a tendency to burn or cake on the walls of the tubes 16. Also, if the material being treated is lowered to a low temperature, it hasa tendency to freeze and form cakes on the tube walls. In both of these cases, the thermal efiiciency of the apparatus is greatly reduced by the layer of material deposited on the walls, and the cross-sectional area of the tubes is also reduced, so that less material can be forced therethrough. In order to overcome these difliculties, and to provide an apparatus which can be used, for example, for cooling an ice cream mixture, means is provided for agitatin the material to be treated and for automatically scraping the interior walls of the tubes 16 while the apparatus is in operation, this means preferably being operated automatically by movement of the material to be treated through the tubes.

This scraping means comprises a member within each of the tubes 16. Each member 50 is formed of a. strip of sheet ma terial twisted into the form of a spiral, so that one or both edges of the strip extend along the tube in the shape of a helix. These twisted stri s, in the embodiment shown, are. made 0. a diameter very slightly than the diameter of the tubes '16, so that the strips or spiral members are rotatable within the tubes but will scrape practically all points of the circumference or the tubes when the stri s are rotated.

The ends 0 each strip project from its tube and are provided with ball-like members 51 which contact loosely with the coy- er members 25 and 26. The ball-like members may rotate easily on the cover members with a minimum of friction and thus act as thrust bearings to prevent longitudinal movement of the spiral members 50 while allowing ro tary movement thereof. The members which are in alinement with the pipes 32 and 33 may have thrust bearings comprising angular offset feet 52 adapted to contact with the ends of the pipes and to ride around on these ends as the spiral members are rotated.

Each of the spiral members 50 is twisted throughout its length in a single direction, as shown in Fig. 5. As the material to be treated is forced through the tubes 16, it will tend to rotate each of the spiral members, and the speed of the resulting rotation will depend on the friction between the spiral member and the tube, on the rate of travel of the material through the tube, and on the viscosity or consistency of the mate rial being treated. Under some conditions, the spiral members 50 may not rotate at all not rotate, though the best results are obtained when the strips do revolve in the tubes.

Inthe case of an ice cream mixture which is being cooled to a comparatively low temperature in an apparatus of this kind, the rotation of the cleaning members or s iral strips 50 serves to prevent freezing o the mixtureon the walls and to scrape away immediately any of the material which does tend to adhere to the tube walls. The rotation of the strips will also agitate the material within the tubes, thus mixing it thoroughly so that all portions of the material come into contact with the walls of the tubes during its passage therethrough. Thus the tubes will not become clogged as the temperature of the mixture falls, and the apparatus will continue to perform efiiciently at temperatures much lower than those possible with apparatus not provided with cleaning and agitating members. Also, it may be used efliciently at high temperatures, since the rotating cleaning and agitating members will prevent the accumulation of scale or deposit on'the inside Walls of the tubes 16, due to the high temperatures used. I

It will now be seen that there has been rovided a heat transfer a paratus which is i ar more practical and e cient than those heretofore used, es ecially when the material being treated is to e raised to comparatively high temperatures or cooled to comparatively low temperatures. Also, an effective automatic cleaning means has been provided for scraping the walls of the tubes to prevent accumulation of solid rnaterialthereon;

While one embodiment of the invention has been disclosed, it isto be understood that the inventive idea may be carriedoutin a number of ways. This application"- is therefore not to be limited to the precise details shown, but is intended to cover all variations and modifications thereof falling within the spirit of the invention or the scope of the appended claims. a

I claim as my invention:

1. In a cooling apparatus, the combination with a container for holding a treating medium, of a plurality of con uits within said container, said conduits providing a passageway foran ice cream mixture, a unidirectional spiral strip rotatably mounted within each of said conduits and in contact with the side walls thereof, and means for preventing longitudinal movement of said strips while allowing rotation thereof, so that and this tends t o scour the walls passage ofsaid ice cream mixture through said conduits will rotate said s iral strips and scrape-the walls of said con uits to prevent accumulation of frozen material thereon. I

2. In a heat transfer apparatiis, the combination with a pair of headers, of a-plurality of conduits extending between said headers, a cover member on one of said headers, a

spirally twisted strip loosely mounted within each of said conduits, a ball upon the end of each of said strips, said balls being adapted to contact with said cover member to provide thust bearin for preventing longitudinal movement 0 said strips while allowing rotary movement thereof, and means for forcing material through said conduits to rotate said strips automatically to scrape the walls of said conduits during the passage of said material.

3. In a heat transfer apparatus, the combination with a conduit for the passage of liquid, of means automatically and continuously operated by the movement of said liquid for scrapin substantially the entire area of the walls 0 said conduit to prevent the formation of deposits thereon. Y

4. In a heat transfer apparatus, the combination with a casing for containing a treating fluid, of a conduit extending through said casing for passage therethrough of liquid to be treated, and a spiral cleaning member normally retained within said conduit to be rotated substantially continuously during passage of liquid to be treated through said conduit by the action of such liquid on said member.

JENS N. JACOBSEN.

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