US2196012A - Heat-transfer apparatus - Google Patents

Description

April 1940- F. B. GILBEI-QT 7 2 ,196,012

HEAT TRANSFER APPARATUS Filed Sept. 25; 1937 4 Sheets-Sheet 1 April 2,1940. F. B. GILBERT HEAT-TRANSFER APPARATUS Filed Sept. 25, 1937 4 Sheets-Sheet 3 vApril 2, 1940- F. B. GILBERT 2,196,012

HEAT-TRANSFER APPARATUS Filed Sept. 25, 1937 4 Sheets-Sheet 4 Patented Apr. 2, 1940 PATENT, OFFICE HEAT-TRANSFER APPARATUS rim 3. Gilbert, Hinadale, m, unmito The Creamery Package Mfg. Chicago,

Application September :5, 1931, Serial No. 105.712

4 Claims. My invention relates to heat-transfer apparatus. More sp'eciflcally,-it relates to heat-transfer apparatus comprising a tank for containing a liquid with respect to which heat is to be transferred andmeans for causing a film of heatof thewalls of the tank.

One of the objects of my invention is to provide heat-transfer apparatus-of the type inditransi'erring liquid to flow over the outer surface cated which will be efficient and rapidin the transfer of heat. 1

A further object of my invention is to provide improved heat-transfer apparatus of the type indicated, in which means are provided for caus- 55 ing'a film of heat-transferring liquid to flow downwardly over the outer surface of the side walls of the tank and for causing a film of heattransferring liquid to flow over the bottom surface of the tank.

A further object of my invention is to provide improved means for supplying steam to heat the liquid which is being circulated to effect the transfer of heat.

A further object of my invention is to provide improved means for draining and recirculatingthe heat-transfer liquid. Further objects and advantages of the invention will be apparent from the description and claims.

In the drawings-- Figure 1 is a plan view of a film flow heattransfer apparatus embodying my invention;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a plan view of the tank-supporting spider and the jet means for causing a film flow over the bottom of the tank;

Fig. 4 is a plan view of a liquid drainage receptacle or sump underneath the tank;

Fig. 5 is a sectional view of a mixing chamber or reservoir substantially on the line 5-5 of Fig. 1 40 Fig. 6 is a plan view of this mixing chamber; Fig. 7 is an enlarged detail plan view showing a portion of the tank with thecover removed; and Fig. 8 is a vertical sectional view on the lin 45 8-8 of Fig. 1.

Referring to the drawings in detail, the construction shown comprises a tank I for containing a liquid with respect to which heat is to be transferred, means 2 for stirring and agitating 50 the liquid in the tank to cause all parts of the liquid to come-in contact with the heat-transfer surfaces, means 3 for causing a film of heattransferring liquid to flow downwardly over the outer surface of the side walls of the tank I, means l for projecting a film of heat-transferring liquid radially outwardly from the central portion of the bottom of the tank I over the outer tank surface, a heat-insulating housing 5 surroundiig the tank and spaced therefrom to provide space for the liquid film flow, a drainage receptacle 6 (Fig. 5) underneath the housing for receiving the liquid which flows over the tank surfaces, a conduit 1 extending upwardly from the drainage receptacle 6 for supplying liquid for the radial film flow, a conduit 8 extending through the bot- 10 tom wall of the housing upwardly in the space between the side wall of the tank and housing for supplying liquid for said downward fiow film, a pump 9 for withdrawing liquid from the drainage receptacle and delivering it to both the 15 conduits, a liquid reservoir It in the line between the pump 9 and conduits l and 8, means II for supplying steam to said liquid receptacle, thermostatic means [2 for controlling the supply of steam, and a discharge outlet l3 for the liquid 20 v in the tank I.

The tank I may be of any suitable material which will not be injured by the liquids with which it is in contact, stainless steel being suitable for this purpose. It is, in general, cyling5 drical in form having cylindrical side walls and a slightly sloping bottom wall I 5. The upper edge f of-the cylindrical portion is supported on the annular breast portion "5 of the insulating housing. The lower sloping bottom I5 is supported 30 on a spider l1 (Figs. 2 and 3) which is adjustable to a limited extent, both vertically and laterally. The stirring and agitating means 2 comprise a rotatable vertical shaft l8 supported on a conical step bearing l9 on the bottom of the tank l, a plurality of radially-extending, stirring blades 20 secured to this shaftxa plurality of vertically-extending blades 2| secured to the ends of the radially-extending blades 20, a plurality of stationary blades 22 secured to the side walls of the tank I, and a motor 23 and transmission 24 for driving the vertical shaft I 8.

The. means 3 for causing the downward flow film comprises an annular distributing pipe 25 lying in an annular chamber 26 surrounding the upper portion of the tank and the verticallyextending pipe 8 for supplying liquid to this annular conduit. The heat-insulating housing 5 comprises a cylindrical portion 21 surrounding the tank I, an upper cover portion 28 secured to the breast portion of the insulating hous ng and a lower bottom portion 29 lying underneath the tank. In general, the walls of this heat-in u ating housing may beformed of a laver of he tinsulating material 30, such as cork, held in place For affording access to the tank, the cover,

portion of the insulating housing may be provided with a pair of doors 32 hinged to the central portion 33 of the cover, as indicated at 34. The motor 23 and transmmsion 24 for driving the agitator may be mounted on this central portion 33 o! the cover.

The circulation oi the heat-transferring liquid is from the sump or receptacle 6 underne h the tank, through the conduit 35 (Figs. 1 and 4) leading to the pump 9, from the pump 9 to the mixing reservoir I0 through the conduit 33, from the mixing reservoir ID to the conduits I and 3, through the conduits 31 and 38, and from the conduits 'I and 8 to form a film flow along the outer surface of the tank I, the film flow draining into the sump 3.

If it is desired to drain the liquid from the sump 3 and from underneaththe tank I, the drain plug 39 (Figs. 1, 2 and 4) may be unscrewed to enable the escape of the liquid. The liquid is discharged rrom the mixing reservoir by means of a standpipe 40 (Figs. 2 and 5) located within the casing 4|, the lower end of which stand pipe is in communication with the discharge conduit 31 leading from the mixing reservoir. When thewater is pumped into the reservoir, it. fills the reservoir and then flows downwardly through the standpipe 40 into the conduit 31 leading to the conduits 'I and 3.

Steam is supplied to the liquid in the mixing reservoir from a discharge nozzle 42 having a number of slotted orifices 43 in its side through which the steam is delivered to the liquid. Steam is supplied to this slotted nozzle 42 from a conduit 44 connected with the steam supply. The amount of steam supplied to the mixing reservoir is controlled by a motor-operated valve 45, which motor-operated valve in turn is controlled by the thermostat I2 subjected to the temperature at the upper end of the mixing reservoir I0. Any suitable thermostatic control and motor valve may be used for this purpose, that shown comprising a construction in which the thermostatic valve is controlled from the thermostat by means of a cable 46 connecting the thermostat with the motor-operated valve. If desired, means may be provided whereby when the temperature of the liquid in the processing tank i reaches a predetermined point, the thermostat !2 will be controlled in such a way that thereafter the tem perature in the mixing chamber iii will be maintained at a lower degree. Any suitable means may be provided for that purpose, that shown comprising a thermostatic element 41 subjected to the temperature of the material in the tank which acts in such a way as to switch the contact controlled by the thermostat in the mixing reservoir when the temperature of the liquid in the processing tank I reaches a predetermined point.

The spider II which supports the bottom of the tank comprises a central hub portion 48 from which radial arms 49 extend, to which may be secured radially-extending supporting members 50, on which the bottom of the tank I rests. The hub portion 48 may be adjusted vertically by means of screws 5| having a threaded engagement with a supporting ring 52 secured to the bottom wall of the housing, the hub portion 48 of the spider resting on the upper ends of said screws. Ihe hub portion of the spider may be adjusted laterally by means of screws 53 threaded into upwardly-extending ears on the collar and engaging the hub 43. The distributing head 4 for causing the film to flow over the bottom surface of the tank has a central chamber 33 to which the liquid is delivered from the vertical conduit I and has a plurality oi radially-extending jet openings 33 which deliver jets of liquid to the under surface of the tank I, causing a film oi liquid to flow radially and outwardly along the under side of the tank. The drainage receptacle or sump 3 underneath the tank is provided with a conduit 31 afiording communication between the supply pipe 33 and the vertical standpipe I. The discharge outlet I3 for draining the liquid from the tank I may be provided with a suitable rotary valve 33 for controlling the discharge.

' The lower casting 53 oi the mixing reservoir is provided with a passage 33 for connecting the pipe 33 from the pump with the vertical discharge pipe 33 surrounding the steam nozzle 42.

Inuse,thetank I isfilledwithaliquidtobe treated, such as milk, or the like. Heat-transierring liquid in the desired amount is supplied to the circulation system through the supply pipe GI, which is then closed by means of the valve 32. The motor 23 is put in operation to start the agitation oi the liquid in the tank I, the motor for the pump 3 is started to put in circulation the heat-transferring liquid, and steam is admitted to the passage 44 leading to the thermostaticallycontrolled valve The circulation caused by the pump 9 delivers the heat-transferring liquid to the annular distributing pipe 23 at the upper edge of the tank I to cause a downward film iiow and also delivers liquid to the distributing head 4 which causes the radial film flow over the bottom surface of the tank I. The flow from these films collects in the bottom-of the heat-insulating housing 5 and flows down into the sump or drainage receptacle 8 from which it is drawn oil by means of the pump 8 through the pipe 35. The thermostat I2 at the upper end of the mixing reservoir I0 controls the admission of steam in such a way as to maintain the desired temperature at the upper end of the mixing reservoir and this desired temperature in turn may be controlled by means of the thermostat 41 which is subject to the temperature of the liquid in the tank I. This latter thermostatic control is such that until the temperature of the liquid in the tank l reaches the desired level the mixing chamber temperature will be relatively high, and such that when the desired temperature of the liquid in the tank has been reached the temperature maintained in the mixing chamber will be relatively lower. This thermostatic control relieves the operator from closely watching the heating and holding process as it automatically takes care of the entire operation from start to finish.

The function of the steam control thermostat is to regulate liquid temperature at the point for which the thermostat is set. This thermostat may have two contact points, one of which limits the liquid temperature during heating while the other limits the liquid temperature while holding at the desired temperature. Thus, if the liquid in the tank is below pasteurizing temperature, the temperature in the mixing chamber may be maintained atapproxlmately 160 degrees, but at the instant the temperature of the liquid in the tank reaches a pasteurizing or other predetermined temperature, the selector switch is operated in such a way that the steam-controlling thermostat thereaftercontrols at a lower temperature. The steam supplied to the reservoir I0 7 through the slots ll mixes with the liquid supplied through thepipe 80*, thus maintaining the liquid at the desired temperature.

The annular distributor pipe 25 is supported by a sheet metal member 63 which inclines downwardly and inwardly toward the tank for causing. the liquid supplied through the spaced Jet openings in the pipe to drain toward the tank. This sheet metal member is provided with a series of teeth 64, the crests of which engage the sides of the tank and cause the liquid to drain against the sides of the tank and fiow downwardly along the sides of the tank.

Further modifications will be apparent to those skilled in the art and it is desired, therefore, that the invention be limited only by the prior art and the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A heat-transfer apparatus comprising a tank for containing a liquid with respect to which heat is to be transferred, said tank having a substantially fiat bottom and having sidewalls extending upwardly from the bottom, means for directinga film of heat transferring liquid downwardly over the outer surface of said side walls and jet means for projecting a film of heat transferring liquid radially outwardly from thecentral portion of the bottom of the tank over the outer surface of said bottom.

2. A heat-transfer apparatus comprising a tank for containing a liquid with respect to which heat is to be transferred, said tank having a substantially fiat bottom and having side walls ex- 3. A heat-transfer apparatus comprising a tank for containing a liquid with respect to which heat is to be transferred, said tank having a substantially fiat bottom and having side walls e:-

said' drain receptacle and delivering 7 level.

tending upwardly from the bottom, means for directing a film of heat transferring liquid downwardly over the outer surface of said side walls and jet means for projecting a film of heat transferring liquid radially outwardly from the central portion of the bottom of the tank over the outer surface of said bottom, a heat-insulating housing surrounding said tank and spaced therefrom to provide space for said liquid film flow, a drain receptacle underneath. said housing for receiving the liquid which flows over the tank surfaces,

a conduit extending upwardly from said drain receptacle for supplying liquid for said radial flow film, a conduit extending through the bottom wall of the housing and upwardly in the space between the side wall of the tank and the housing for supplying liquid for said downward fiow film, means for withdrawing liquid from said drain receptacle and delivering it to bothsaid conduits, and means for supplying wardly over the outer surface of said side walls and jet means for projecting a film of heat transferring liquid radially outwardly from the central portion of the bottom of the tank over the outer surface ofsaid bottom, a heat-insulating housing surrounding said tank and spaced therefrom to provide space for said liquid film fiow, a

drain receptacle underneath said housing for receiving the liquid which fiows over the tank surfaces, a conduit extending upwardly from said drain receptacle for supplying liquid for said radial flow film, aonduit extending through the bottom wall of th housing and upwardly in the space between the side wall of the tank and the housing for supplying liquid for said downward flow film, means for withdrawing liquid from said conduits, a liquid receptacle injthe line between said pump and conduits in which a liquid level is maintained, and means for supplying steam to said liquid receptacle below the liquid mm 3. 0113mm,

it to both-

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