US2535777A - Pulp evaporator - Google Patents

Description

b Dec. 26, E H. BICKLEYA PULP EVAPORATOR Filed April 12, 1946 INVENTOR fT/zme-rrfi Fm/n45);

Patented Dec. 26, 1950 UNITED STATES PATENT OFFICE 2,535,777 PULP EVAPQRATOR Everett H. Bickley, Bala-Cynwyd, Pa. Application April 12, 1946, Serial No. 661,623

2 Claims.

The present invention relates to evaporators and more particularly to an apparatus for concentrating tomato pulp.

Heretofore the usual and common method of boiling down tomato liquid to produce 2/1 tomato pulp consists of heating the tomato liquid by means of live steam coils immersed in the liquid. The top of the kettle is open and huge clouds of steam roll out filling the room to such an extent that large fans must be operated to carry it away. Every pound of water evaporated from the tomato liquid turns into 30 cubic feet of steamgancl 3000 to 4000 pounds of water are evaporated from a single kettle in 25 minutes.

The steam entrains also corrosive vapors or droplets which attack the steelwork in the penthouse. It carries away also flavors which may be of value if they could be retained.

Each pound of steam condensed in the coils gives up 880.6 E. t. u. to form water and in cooling down to the temperature of the trap discharge liberates about 102 additional heat units. This is 982.6 B. t. u. The fluids evaporated from the tomato liquid require about 970 B. t. u. per pound, plus about 145 B. t. u. per poundto heat it up to the boiling point. This is a total of 1115 B. t. u. Allowing for recondensation, radiation, heat losses and specific heat of the containers (9%) it would require about 1.04 pounds of steam to remove 1 pound of tomato liquid. It is obvious that one kettle will take about 100 boiler horse ower to keep it going, or about 50 cubic feet of steam per second will be rolling out of the kettle.

Some of the objects of the present invention are: to provide an improved apparatus for boiling down tomato liquid toproduce tomato pulp; to provide a new and novel apparatus for evaporating tomato fluid; to provide an apparatus for evaporating tomato liquid wherein corrosive vapors are prevented from escaping and in consequence there is no less of flavor; to provide an evaporator for tomato fluid wherein the amount of steam required to convert one pound of tomato liquid is materially reduced; to provide an evaporating system applicable either to batch or continuous evaporation, both with a minimum of recondensation, radiation, and heat losses; to provide a novel closed system of tomato fluid evaporation, and to provide other improvements as will hereinafter appear.

Referring to the drawings, Fig. 1 represents diagrammatically a side elevation partly broken away of an evaporator embodying one form of the present invention; Fig. 2 represents diagrammatically a side elevation of a modified form of the invention; and Fig. 3 represents a sectional detail of the three way valve and associated parts.

Referring to Fig. l of the drawings, one form of apparatus of the invention is shown for concentrating vegetable pulp in a batch operation, the apparatus being here illustratively described as applied to tomato pulp for use in the manufacture of ketchup, sauces and the like.

The tomato fluid to be reduced to pulp is placed in a cooking vessel 10, of the open top type having a sealing closure ll arranged to be clamped in place by suitable hold-down clamps l2, while the bottom is, preferably, funnelled to a drain pipe I3 provided with a shut-off valve M. A safety valve [5 may be provided in the closure l l or other location as will be understood.

In order to preheat the tomato fluid, a heating coil 16 is mounted within the kettle liiwith its lower end passing through the kettle wall to communicate with a trap and air vent I! located in a drain pipe 18. The upper end of the coil 15 also passes through the kettle wall to communicate with a steam supply pipe 20 leading to a source of steam supplied by a pipe 2|. A control valve 22 is located in the pipe 20 in order to shut ofi the steam to the kettle at the proper time as will later be described.

For the purpose of utilizing the vapor rising from the tomato fluid while boiling, a centrifugal pump 23 is provided having its inlet connected by a pipe 24 for communication with the space in the vessel It above the fluid 1evel, and its discharge connected through a T-fitting 25 with the pipe 20. This latter connection is made between the valve 22 and the kettle 10. A pressure gage 26 may be included in the pump inlet pipe 24. A steam turbine 21, preferably of the DeLaval type is arranged to drive the pump 23 and is supplied with steam from the supply pipe 2! through a control valve 28.

In operation the valve 28 is initially closed and the valve 22 is opened so that steam is supplied directly to the coil I 6 until the fluid reaches the boiling point. At this point the valve 22 is closed and the valve 28 is opened to start the pump 23. The action of the pump 23 is to draw the vapor from the vessel 10 and compress it to a higher pressure as delivered to the coil It, thus causing the heat to fiow into the tomato fluid to continue the boiling and give 01f more vapors. The vapors in the coil I6 will condense andbe drawn off by the trap H. In this way the fluids "will be extracted from the tomato fluid until the 3 latter becomes tomato pulp. When this stage is reached the pump 23 is stopped and the pulp drawn off by opening the valve It in the drain pipe l3.

In the foregoing batch operation the starting temperature of the tomato liquid is approximately 170 F., since the tomato liquid has just been scalded. The vapors go into the pump in a saturated condition, atmospheric pressure or a little higher. The vapors come out of the pump superheated due to the compressing action of the pump. These vapors go into the coil I6 where they give up heat to the tomato liquid, causing it to boil vigorously. When the vapors have cooled down to near the temperature of the liquid, condensation takes place and the condensate is trapped out of the system. Heretofore a ton of coal was required to process 103 bushels of tomatoes, while with the apparatus of this invention one tonof coal should process 340bushels of tomatoes or more.

Referring to Figure ,2 of the drawings a modified form of the invention is for continuous operation wherein a conveyor 39 delivers the tomatoes to a decorticator and scalder 3! arranged to discharge the resultant tomato fluid through a strainer 32'to'a centrifugal pump 33' which discharges the fluid by way of a pipe 34 into a closed preheater tank This preheating of the fluidtakes place through the medium of a coiliiii submerged in thefiuid and preferably heated by exhaust steam as will be described hereinafter. The tank35 discharges at the bottom through a valve 3? arranged in one position to communicate with a drain pipe 38 and in operating conditionof the apparatus to communicate with a centrifugal pump it. The discharge of the pump 49 delivers the preheated fluid by way of a pipe ii to an evaporating vessel 42 similar to that described for Figure 1, except, in this instance, the heating coil :33 is only in the circulation of compressed vapor from a turbopump Mi, which hasits inlet in communication with the vapor space of the vessel :32 bya pipe 45 and its outlet to a drain trap G3. The pump it is driven by a steam turbine Lilsupplied by a pipe (i8. from a main steam pipe &which is connected to a source Ofsteam supply. The vessel it has a discharge at the bottom by way of a valve 5| arranged in operating condition of the system to communicate with the intake of a centrifugal,

pump 52 and in inoperative condition of the systemto communicate with a drainpipe 53. A paddle type of agitator Edmay be located within the vessel 42, and be driven by an electric motor 55.

In order tocomplete the evaporation of the tcmatofiuid; a second evaporating vessel 55 is provided into which the partially concentrated fluid is delivered by a pipe bl from the discharge of;the pump Thevessel 55 is of the closed type heretofore described having a heater coil 58 therein connected at one end to the discharge of a turbo-pump iii! and at the other end. to a drain trap 6!. The pump to is arranged to be driven from a steam turbine 52 receiving steam by way of a pipe 63 from the main supply pipe 5%. The inlet to the pump communicates with the vapor space of the vessel 55 by a pipe 6t. Preferablythis vessel 56 has a bottom in the form of an elongated funnel b5 arranged to discharge through a control valve 66 to a pipe which delivers the evaporated pulp to a suitable container as will be understood. An agitator 68 preferably mounted for rotation 4 within the body of pulp and is driven by an electric motor 19 or other power means.

For economical operation exhaust steam from the turbines il and 62 discharges by way of the respective pipes H and '52 to a conduit 73 which communicates with and supplies heat to the coil 36. Also the centrifugal pumps 33, 49 and 52 are respectively arranged to exhaust into the conduit 13, by pipes Hi, 75 and it. The main steam supply pipe 50 terminates within the decorticator 3! and functions in the scalding of the tomatoes.

' In the operation of the continuous system of Fig. 2,-the tomato liquid as discharged from the strainer is free from skins and seeds and enters the preheater seat a temperature approximately 180 F. This, represents a saving at this point of at least 35 B. t. u.s per pound. when delivered to the first evaporator 42 from the preheater 35 its temperature has risen to 200 F. or 212 F. and in this evaporator 42 the heating takes place below atmospheric pressure in order to preserve the color, flavor and to prevent the thickened pulp from being burned by'the coils 43. Hence,

by reason of the vacuum conditions the tomato liquid enters the second evaporator at a temperature of approximately and since no additional steam orcondensingwater is necessary to operate the unit there'is a large saving of B. t. u.s which is, of course, reflected in a saving of coal as compared to other evaporating systems. This is evident because the vacuum is created by exhaust steam from the turbines and pumps.

In the system of'Fig; 2 attention is directed to the novel three wayvalve discharge employed with each of the two evaporators 42 and 56 in that the ported valve plugli; (Fig. 3) not only controls communication between an evaporator and the respective discharge outlets 6? and '58 but also forms a bear-ingfor the shaft 88 of the agitator 68. A hand lever 81 serves to shift the valve plug to diiferent control positions as will,

be understood.

I claim:

1.1 :1 an apparatus for evaporating tomato fluid, the combination of a plurality of evaporatingkettlesconduit means interconnecting kettles for transferring said liquid from one kettle to another in sequence relation from the.

bottom of one kettle to the top of the next kettle,

a preheater connected to a source of tomato fluid,

means for feeding said fluid from said preheater to the first kettle of said sequence, heating coils in the respective kettles, means including rotary compressors for respectively withdrawing vapors from saidkettles and into the respective heating coils, anelongated steep-sided funnel in the bottom of the last sequence kettle for discharging the evaporated tomato pulp, and an agitator means mounted in said funnel.

2. In anapparatus for evaporating tomato fiuid, the combination of two evaporating kettles.

creasethe temperature of the surrounding vapors,

means including a pump ..fortransferr-ing fluid from the bottom ofsaid first kettle to the top' of the second kettle, a heating coil in said second kettle, means including a rotary compressor for drawing vapor from said second kettle and supplying it under pressure to the heating coil in said second kettle to increase the temperature 5 of the surrounding vapors, and means to dis charge the concentrated tomato pulp from said second kettle.

EVERETT H. BICKLEY.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 15 246,807

6 UNITED STATES PATENTS Name Date Dunn Sept. 27, 1910 Kestner 1 July 11, 1911 VOuga Feb. 25, 1913 Kestner May 6, 1913 De Baufre Sept. 13, 1921 Suczek May 12, 1925 Teetsow Sept. 20, 1932 Kleinschmidt 1 Jan. 2,. 1940 Jensen July 28, 1942 FOREIGN PATENTS Country "Date Great Britain Dec. 10, 1925 Italy Feb. 24, 1926

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