US1959120A - Heat exchange apparatus - Google Patents

Description

May 15, 1934. A. zlsKA HEAT EXCHANGE APPARATUS Filed Feb. 18, 1932 N SE lil/7111 l INENTOR. ,5 l5 36 kAch-1m Zz'skq ATTORNEY.

Patented May 15, 1934 UNITED STATES HEAT EXCHANGE APPARATUS Adam Ziska, Wauwatosa, Wis., assignor to A. 0.

Smith Corporation, Milwaukee, Wis., a corporation of New York Application February 18, 1932, Serial No. 593,709

7 Claims.

This invention relates to heat exchange apparatus and especially to improvements in the construction of a rotary drum which serves as a heat transfer element in apparatus in which the drum is intended to be submerged in a liquor which is to be heated or cooled. In an apparatus of this kind, the liquor which is to be heated or cooled is placed in a container (not shown), and hot or cold uid is circulated through the rotatable l0 heat transfer element.

It is an object of the present invention to provide a rotatable heat transfer drum to the inner and outer surface of which unobstructed access may be had during rotation thereof. Another object is to provide a cooling drum which oifers small resistance to the rotation thereof in a liquor. A further object is to provide a selfpumping, rotary drum which may be provided with a baffle and/or a scraper adjacent the inner and the outer surfaces of the drum while the drum is being rotated. A further object is to provide a simplified mounting which consists of a small number of parts and a minimum of joints through which leakage may occur. Other objects of the invention will be apparent from the following description and the accompanying drawing.

According to the invention, a heat transfer element is constructed which is capable of having its temperature changed at will while it is immersed in a liquor for the purpose of controlling the temperature of the latter. The element is capable of conducting heat energy through its walls and of being rapidly rotated to provide for a high rate of heat transfer through these walls. The construction of the element is such that its external conducting surfaces are readily accessible during rotation of the element so that foreign material may be removed therefrom and so that stationary means may be positioned adjacent to these surfaces to prevent or reduce the tendency of the liquor in which the element is immersed from rotating with the element.

The following specic embodiment is an illustration of one mode of carrying out the invention but it is to be understood that the invention is not limited thereto and that modifications may be made without departing from the invention.

In the drawing:

Figure 1 is a vertical cross-sectional View of the drum taken along line 1 1 of Fig. 2;

Fig. 2 is a cross-sectional view of the drum taken along line 2-2 of Figure 1 with part of the structure broken away to show the spider structure in greater detail; and

ing. yThe innermost and outermost walls 24 and mounted on a hollow spider 2 which spider is 60 secured to and rotated by a hollow shaft 3. The lower end of the shaft 3 is provided with a flange 4 integral therewith. The flange is provided with holes 5 through which screws 6 pass and extend into tapped holes 7 in a boss 8 which is an in- 65 tegral part of the spider 2. The flange 4 is seated in a machined recess 9 in the top of boss 8. The hollow shaft is divided interiorly into two longitudinal passages 10 and 11 by a mid-web or partition 12 which extends diametrically across the 70 enclosure and longitudinally of the shaft.

The spider 2 comprises a plurality of radiating arms or `members 13 arranged substantially at equal distances apart. The arms are hollow and each one is divided interiorly by a web or partition 16 which extends diametrically and horizontally across and along the interior of the arms 13 to provide two passages 14 and 15. The passages 14 communicate at the center with the passage 10 in the shaft 3 through an opening 17 80 in the boss 8. The passages 15 in `the lower part of the arms 13 are united centrally of the spider to inclose the channel 18 which communicates with the passage 11 in shaft 3 through an opening 19 in partition 16 and opening 20 in boss 8. Intercommunication between passages 14 and 15 and between passages 17 and 20 in the `boss 8 is prevented by an upstanding D-shaped flange 21 surrounding opening 19 and extending upwardly from the partition 16 to the boss 8 and to the partition 12. The lower end 22 of partition 12 and the upper end 23 of flange 21 may be enlarged to provide suicient bearing area so that an apertured gasket may be suitably positioned and properly supported to prevent leakage between the flanged 'shaft 3 and the spider2.

Secured to and depending from the spider 2 is the hollow shell 1. This shell has a frusto-conical shape and has its larger diameter at its lower end. The walls of the shell comprise three spaced walls 24, 25 and 26, each having a frusto-conical shape. The walls are relatively fixed by means of spacing blocks 27 which are positioned between the walls and'secured thereto by welding or rivet- 26 extend downwardly beyond the lower end of the intermediate wall 25 and are secured together by an annular anged ring 28 welded or brazed thereto. A flange 29 on the ring extends into the space between the walls 24 and 26 and ts close- 110 ly therein. The welded union effects a uidtight seal at the lower end of the shell.

The upper ends of the walls 24, and 26 are staggered, the innermost wall 24 extending upwardly the least distance and the outermostl wall 26 extending upwardly the greatest distance. The upper end of the shell 1 is sealed by an annular stepped. ring or band 30, asshown in Fig. 3. The outer face of the band is cut away to provide the steps 31 and 32 which provide spacing means for the walls 24, 25 and 26, and annular seats or notches 33 are cut in the steps to provide seats for receiving the ends of the walls 24, 25 and 26, where they are welded or brazed to the band 30. Y

The band is secured to the outer ends of the arms 13 by welding, brazing or, preferably, by being integrally cast therewith. As shown in Figures 1 and 2, openings 34 and 35 through the band 30 are made to align with passages 14 and 15 respectively in each of the arms 13 of the spider 2.

The shell 1, spider 2 and shaft 3 are arranged about a common axis so that the shaft and drum may be rapidly rotated. The spaced walls 24, 25 and 26 form chambers 36 and 37 therebetween which communicate with each other at the lower end of the shell 1 below the end of the interu mediate wall 25. The upper end of chamber 36 vin the shell 1 and thence downwardly through the chamber 37 to the bottom of the shell, around y the lower end of Wall 25 into chamber 36, thence upwardly therethrough to the top of the shell, through opening 35 in band 30, passage 15 in spider 2, opening 19in partition 16, 0pening2 in boss 8 into passage 11 in shaft 3. The circulated fluid should be so directed as to effect contact with substantial and distributed portions of the walls of the drum.

Positioned in contact with the outer surfaces of walls 24 and 26 are Scrapers 38 and 39 which extend substantially the length of the cylinder 1 and serve to keep the cooling surfaces of the drum clean. The Scrapers are held in position by brackets or supports 40 and 41 which may be secured to the wall and/or bottom of the container for the liquor. The blades of the Scrapers may be positioned substantially normal to the surfaces of the drum or they may be positioned at an angle thereto so as to either scrape or drag the surface of the drum.

The above described structure constitutes a heat transfer element which may be submerged in a fluid and rapidly rotated. The rapid rotation of the structure in the liquor will erode and tendtodestroy the normally stagnant :film of fluid which adheres to the surfaces of the structure and, hence, will enhance the rate of transfer of heat between the structure and the liquor. In addition, the centrifugal forces which result from rotation of the frustoconical drum will cause the liquor to circulate axially through the rotating drum. On account'of the angular relationship between the surfaceV of the drum and its axis of rotation, the resultant components of ing movement brings fresh liquor in contact with the heat conducting surfaces of the drum and hence increases the rate of heat transfer.

In effecting a transfer of heat between the drum and a liquor, solids and gases if present in the liquor tend to adhere so tenaciously to the heat transfer surfaces of the drum that they will not be removed by the erosive action of the liquor. When this occurs, the rate of heat transfer is materially reduced. The deposits are removed or reduced and the efficiency of heat transfer is improved by contact members or Scrapers which are arranged to bear on the heat conducting surfaces of the drum. By providing a support in the form' of a spider which is attached at one end or intermediate the ends of the drum so as to occupy only a relatively small area of the surface of rotation which area extends over a comparatively short axial distance of the drum, an opening'or openings are provided so that scraping arms can be disposed on the inside as well as on the outside surfaces of the drum and the heat transfer coefficient of the unit can be correspondingly increased. It has been found that a unitary perforate support which is afforded by a spider having radiating arms which are attached in the described manner is a sufficient support for the drum, that itprovides a structure which avoids interference with Scrapers forthe inside and the outside surfaces of the drum and permits circulation of the liquor through the drum.

The invention is not limited to the particular arrangement of the structural details described and illustrated in the specific embodiment. For example, the interwall structure of the shell may be variously partitioned to provide other paths for the course of the fluid.l Electrical resistance elements maybe distributed within the shell with leads therefrom extending into the shaft for the purpose of heating the shell. The shell may be perfectly cylindrical and other means may be provided for circulating the liquor in which the drum is immersed, and various other modifications in the structure may be made without departing from the invention.

l.' claim:

1. A heat exchange apparatus which comprises a drum having spaced wall members and a partition therebetween which forms supply andreturn passages through the wall for circulating liquids, a support having arms attached to thek drum within a relatively small area of the surface of revolution of the drum, said arms having longitudinal supply and return passages which are arranged to communicate with the supply and return passages of the drum respectively; a seal on the edges of the outside walls, said seal being spaced from said partition to provide communication between the supply and return passages, a rotatable shaft having longitudinal passes therein, and apertured means for mounting the support on the shaft with the passages in the shaft separately communicating with the supply and return passages in the arms of the support.

2. A heat exchange apparatus which comprises a heat-conductive, frusto-conical drum which has spaced walls, a liquid-tight seal at one end of the drum whichcloses the space between the edges of the walls, and a partition positioned intermediate and in a spaced relationship to the walls, said partition terminating short of the sealedend of the drum thereby forming a supply and return passageway within the drum, means extending across the edges of the spaced walls andthe partition for attaching the other ends of the wallsl and partigr.

tion, said means having supply and return apertures that are arranged to communicate with said supply and return passageways, and a support having arms which are secured to said means, said arms having supply and return passages which are arranged to communicate with said supply and return apertures. p

3. A heat exchange apparatus which comprises a heat-conducting drum having a passageway within the wall of the drum for distributing means to control the temperature of the drum, said drum being open at its ends and having a circular crosssection at right angle to the axis of the drum, and means for rotatably supporting the drum having passages for feeding and discharging said heat control means at one end of the drum, said supporting means being secured to said drum in an area having a comparatively short dimension as measured along the axis of the drum.

4. A heat exchange apparatus which comprises a heat-conducting drum which is open at its ends and has fluid-conducting passages in its walls, and perforate means positioned at one end of the drum for supporting and rotating the drum about its axis, said means having passages which communicate with the opposite ends of said fluidconducting passages.

5. A heating device which comprises a drum which is open at the ends and is capable of being submerged in a liquor and of being rotated about its axis, spaced wall members in the drum having supply and return passages therebetween for distributing heating means therein, a support for the drum having transverse and longitudinal channels, said longitudinal channels at one end of the drum communicating with the ends of said supply and return passages in the wall, a rotatable hollow shaft axially disposed to the drum, and means for mounting the shaft centrally on said support, said support having ports which form communication between the hollow shaft and said channels.

6. A heat exchange apparatus which comprises a heat-conducting drum which has a circular cross-section normal to its axis, said drum oomprising spaced walls, a seal at one end of the drum which closes the space between the edges of the walls, and a partition positioned intermediate and in a spaced relationship to each of the Walls, said partition terminating short of the sealed end of the drum and extending to the other end of the drum thereby forming a supply and return passageway within the drum, an annular member or ring secured to said other end of the drum and extending across the edges of the spaced Walls and the partition, said member or ring having annular grooves on the outer face thereof which grooves form steps to which the edges of the walls and partition are fastened and said member or ring also having apertures therethrough which communicate individually with the supply and return passageways in the drum, and a spider which has hollow arms radiating to and secured to said stepped rings at the apertures therein, said hollow arms forming supply and return passages which communicate individually with the apertures in the stepped ring.

7. A heat exchange apparatus which comprises a heat-conducting drum with fluid-conducting passages in its wall, perforate means positioned at one end of the drum for supporting and rotating the drum about its axis, said means having passages which communicate with the opposite ends of the uid-conducting passages in the wall of the drum and having a relatively short dimension axially of the drum, and Scrapers which bear on the inner and outer walls of the drum to insure a relative rotational velocity between the drum and any liquid in which it is rotated and prevent the formation of surface lms which adhere to the Wall of the drum and decrease the rate of heat transfer.

ADAM ZISKA.

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