US20030213585A1

US20030213585A1 - Heating and cooling of viscous food products

Info

Publication number: US20030213585A1
Application number: US10/393,927
Authority: US
Inventors: David Reznik
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-03-21
Filing date: 2003-03-20
Publication date: 2003-11-20

Abstract

An improved heat exchange system and methodology, and an improved material treatment system and methodology, based on that heat exchange system, for providing improved pasteurized and sterilized packaged food products is disclosed. Improved pasteurized and sterilized packaged food products produced thereby are also disclosed.

Description

FIELD OF THE INVENTION

The present invention relates to heat exchange generally and more particularly to sterilization of food products using highly efficient heat exchangers.

BACKGROUND OF THE INVENTION

The following U.S. Pat. Nos. of the applicant are related to the subject matter of the present invention: 6,158,504; 5,928,699, 5,670,198 and 5,768,472.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved heat exchanger and improved pasteurized and sterilized food products realized by use of the improved heat exchanger.

There is thus provided, in accordance with a preferred embodiment of the present inventions a vacuum heat exchange system including:

a container partially filled with a liquid and maintained under a vacuum;

a first heat exchanger disposed in the liquid in the container, the first heat exchanger receiving, a first fluid material, heating the liquid and thereby cooling the first fluid material; and

a second heat exchanger disposed outside of the liquid in the container, the second heat exchanger receiving a second fluid material and being heated by vapors of the liquid, thereby heating the second fluid material,

at least one of the first and second heat exchangers including an agitator for agitating, the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material. Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

In accordance with a preferred embodiment of the present invention, at least one of the first and second heat exchangers includes a scraped surface heat exchanger.

Additionally, the vacuum heat exchange system also includes an electroheater for heating the first fluid material prior to receipt thereof by the first heat exchanger. Alternatively, the vacuum heat exchange system also includes an electroheater for receiving the second fluid material from the second heat exchanger.

In accordance with a preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the vacuum heat exchange system also includes an electroheater for heating the first fluid material prior to receipt thereof by the first heat exchanger and the first fluid material is received by the electroheater from the second heat exchanger.

There is also provided, in accordance with a preferred embodiment of the present invention, a material treatment system including:

an electroheater operative to rapidly heat a first fluid material; and

a vacuum heat exchange subsystem operative to rapidly cool the first fluid material following electroheating thereof, the vacuum heat exchange subsystem including:

a container partially filled with a liquid and maintained under a vacuum;

a first heat exchanger disposed in the liquid in the container, the first heat exchanger receiving the first fluid material, heating the liquid and thereby cooling the first fluid material; and

at least one of the first and second heat exchangers including an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

In another preferred embodiment of the present invention the electroheater supplies the first fluid material to a holding tank, prior to receipt of the first fluid material by the first heat exchanger. Alternatively or additionally, the electroheater receives the second fluid material from the second heat exchanger.

In accordance with still another preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the electroheater heats the first fluid material prior to receipt thereof by the first heat exchanger and the first fluid material is received by the electroheater from the second heat exchanger.

There is additionally provided, in accordance with a preferred embodiment of the present invention, a material treatment system including:

electroheater operative to rapidly heat a first fluid material;

a first vacuum heat exchange subsystem operative to rapidly cool the first fluid material following electroheating thereof, the first vacuum heat exchange subsystem including:

a container partially filled with a liquid and maintained under a vacuum;

at least one of the first and second heat exchangers including an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material; and

a second vacuum heat exchange subsystem operative to preheat the first fluid material prior to electroheating thereof, the second vacuum heat exchange subsystem including:

a container partially filled with a liquid and maintained under a vacuum;

a third heat exchanger disposed in the liquid in the container, the third heat exchanger receiving a third fluid material, heating the liquid and thereby cooling the third fluid material; and

a fourth heat exchanger disposed outside of the liquid in the container, the fourth heat exchanger receiving the first fluid material and being heated by vapors of the liquid, thereby heating the first fluid material,

at least one of the third and fourth heat exchangers including an agitator for agitating, the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

In accordance with a preferred embodiment of the present invention, the third heat exchanger includes an agitator for agitating the third fluid material passing therethrough to enhance heat exchange generally throughout the third fluid material. Alternatively, the fourth heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Additionally or alternatively, both of the third and fourth heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

In accordance with a preferred embodiment of the present invention, at least one of the first and second heat exchangers includes a scraped surface heat exchanger. Additionally or alternatively, at least one of the third and fourth heat exchangers includes a scraped surface heat exchanger.

In another preferred embodiment of the present invention, the electroheater supplies the first fluid material to a holding tank, prior to receipt of the first fluid material by the first heat exchanger.

There is further provided, in accordance with a preferred embodiment of the present invention, a packaged food product characterized in:

having a viscosity exceeding approximately 5,000 centipoise;

being sterilized; and

being aseptically packaged.

Preferably, the packaged food product has a pH exceeding approximately 4.5.

There is yet further provided, in accordance with a preferred embodiment of the present invention, a packaged humus food product characterized in:

being sterilized; and

being aseptically packaged.

There is still further provided, in accordance with a preferred embodiment of the present invention, a packaged egg food product characterized in:

being sterilized; and

being aseptically packaged.

There is additionally provided, in accordance with a preferred embodiment of the present invention, a packaged egg food product characterized in:

being sterilized; and

being aseptically filled and sealed following sterilization and cooling thereof.

Preferably, the packaged egg food product is coagulated.

There is further provided, in accordance with a preferred embodiment of the present invention, a packaged egg food product characterized in:

being pasteurized to at least 75 degrees Centigrade;

being aseptically filled and sealed following pasteurization and cooling thereof; and

being liquid.

There is also provided, in accordance with a preferred embodiment of the present invention, a vacuum heat exchange method including:

partially filling a container maintained under a vacuum with a liquid;

receiving a first fluid material in a first heat exchanger disposed in the liquid in the container, heating the liquid and thereby cooling the first fluid material; and

receiving a second fluid material in a second heat exchanger disposed outside of the liquid in the container, heating the second heat exchanger by vapors of the liquid, thereby heating the second fluid material,

where at least one of the first and second heat exchangers includes an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

In another preferred embodiment of the present invention, the vacuum heat exchange method also includes heating the first fluid material in an electroheater prior to receipt thereof by the first heat exchanger. Additionally or alternatively, the vacuum heat exchange method also includes receiving the second fluid material into an electroheater from the second heat exchanger.

In yet another preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the vacuum heat exchange method also includes:

receiving the first fluid material from the second heat exchanger; and

heating the first fluid material using an electroheater prior to receipt thereof by the first heat exchanger.

There is further provided, in accordance with a preferred embodiment of the present invention, a material treatment method including:

rapidly heating a first fluid material using an electroheater; and

rapidly cooling the first fluid material following electroheating thereof by:

partially filling a container maintained under a vacuum with a liquid;

receiving, the first fluid material in a first heat exchanger disposed in the liquid in the container, heating the liquid and thereby cooling the first fluid material; and

In another preferred embodiment of the present invention, the vacuum heat exchange method also includes supplying the first fluid material to a holding tank from the electroheater prior to receiving the first fluid material in the first heat exchanger. Additionally or alternatively, the vacuum heat exchange method also includes receiving the second fluid material into the electroheater from the second heat exchanger.

In still another preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the vacuum heat exchange method also includes:

receiving the first fluid material by the electroheater from the second heat exchanger; and

heating the first fluid material in the electroheater prior to receipt thereof by the first heat exchanger.

There is yet further provided, in accordance with a preferred embodiment of the present invention, a material treatment method including:

rapidly heating a first fluid material using an electroheater; and

rapidly cooling the first fluid material following electroheating thereof by:

partially filling a container maintained under a vacuum with a liquid;

where at least one of the first and second heat exchangers includes an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material; and

preheating the first fluid material prior to electroheating thereof by:

partially filling a container maintained under a vacuum with a liquid;

receiving a third fluid material in a third heat exchanger disposed in the liquid in the container, heating the liquid and thereby cooling the third fluid material; and

receiving the first fluid material in a fourth heat exchanger disposed outside of the liquid in the container, heating the fourth heat exchanger by vapors of the liquid, thereby heating the first fluid material,

where at least one of the third and fourth heat exchangers includes an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

In accordance with a preferred embodiment of the present invention, the third heat exchanger includes an agitator for agitating the third fluid material passing therethrough to enhance heat exchange generally throughout the third fluid material. Alternatively, the fourth heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material Additionally or alternatively, both of the third and fourth heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.

Preferably, at least one of the first and second heat exchangers includes a scraped surface heat exchanger. Additionally or alternatively, at least one of the third and fourth heat exchangers includes a scraped surface heat exchanger.

In another preferred embodiment of the present invention, the material treatment method includes supplying the first fluid material to a holding tank from the electroheater prior to receiving, the first fluid material in the first heat exchanger.

There is additionally provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged food product including:

producing a food product having a viscosity exceeding approximately 5,000 centipoise;

sterilizing the food product; and

aseptically packaging the food product.

Preferably, the packaged food product has a pH exceeding approximately 4.5.

There is further provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged humus food product including:

sterilizing the humus food product; and

aseptically packaging the humus food product.

There is still further provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged egg food product including:

sterilizing the egg food product; and

aseptically packaging the egg food product.

There is yet further provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged egg food product including:

sterilizing the egg food product;

cooling the egg food product; and

aseptically filling and sealing the egg food product in a package.

Preferably, the egg food product is coagulated.

There is additionally provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged liquid egg food product including:

pasteurizing the liquid egg food product to at least 75 degrees Centigrade;

cooling the liquid egg food product; and

aseptically filling and sealing the liquid egg food product in a package.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: [0119]
FIG. 1A is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with a preferred embodiment of the present invention; [0120]
FIG. 1B is a sectional illustration of a portion of an agitator operative in accordance with a preferred embodiment of the present invention; [0121]
FIG. 2 is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with another preferred embodiment of the present invention; [0122]
FIG. 3 is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with still another preferred embodiment of the present invention; [0123]
FIG. 4 is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with a preferred embodiment of the present invention; [0124]
FIG. 5 is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with another preferred embodiment of the present invention; [0125]
FIG. 6 is a temperature-time graph illustrating aspects of operation of embodiments of the present invention; [0126]
FIG. 7 is a simplified illustration of an electroheating system useful with highly viscous materials and products containing particles; and [0127]
FIG. 8 is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with yet another preferred embodiment of the present invention. [0128]

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to FIGS. 1A and 1B, which are simplified sectional illustrations of a vacuum heat exchange system constructed and operative in accordance with a preferred embodiment of the present invention As seen in FIG. 1A, the vacuum heat exchange system preferably includes a thermally insulated [0129] enclosure 100, the interior of which communicates with the ambient atmosphere via a vacuum pump 102, which preferably maintains the interior of enclosure 100 at subatmospheric pressure, typically about 29″ of mercury.
[0130] Enclosure 100 is partially filled with a cooling liquid 104, preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure 100. A heated fluid material 106, such as a heated food product which has undergone electroheating, is preferably supplied to a conduit 108 which extends through the liquid 104. As the heated fluid material 106 passes through the conduit 108, in thermal contact with the walls thereof, it becomes cooled by evaporating the liquid 104. The cooled fluid material then flows from the conduit 108.
In accordance with a preferred embodiment of the present invention, an [0131] agitator 110, typically in the form of an elongate shaft 112, having outwardly extending vanes 114, is disposed in conduit 108, and rotated therein about an axis 116, as by a motor 118, to provide enhanced uniformity of thermal contact between the heated fluid material 106 and the walls of the conduit 108. A preferred type of conduit 108 and agitator 110 are together known as a scraped surface heat exchanger.
In accordance with a preferred embodiment of the present invention a cooling liquid [0132] 120, preferably water, is caused to pass through a conduit 122, preferably a coil, which extends through enclosure 100, above the level of the cooling liquid 104. The temperature of the cooling liquid 120 is preferably sufficiently low as to cause vapors of the cooling, liquid 104 to condense upon contact with the outer walls of conduit 122 and to fall downward into cooling liquid 104, as drops 124.
Reference is now made to FIG. 2, which is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with another preferred embodiment of the present invention. As seen in FIG. 2, the vacuum heat exchange system preferably includes a thermally insulated [0133] enclosure 200, the interior of which communicates with the ambient atmosphere via a vacuum pump 202, which preferably maintains the interior of enclosure 200 at subatmospheric pressure, typically about 29″ of mercury.
[0134] Enclosure 200 is partially filled with a cooling liquid 204, preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure 200. A heated liquid 206, such as heated water, is preferably supplied to a conduit 208, preferably a coil, which extends through the liquid 204. As the heated liquid 206 passes through the conduit 208, in thermal contact with the walls thereof, it heats the liquid 204, generating heated vapor 214.
In accordance with a preferred embodiment of the present invention, a [0135] cool fluid material 210 is caused to pass through a conduit 212, which extends through enclosure 200, above the level of the cooling liquid 204. As the cool fluid material 210 passes through the conduit 212, in thermal contact with the walls thereof, it becomes heated by the heated vapor 214 from liquid 204. The heated fluid material then flows from the conduit 212.
In accordance with a preferred embodiment of the present invention, an [0136] agitator 220, typically in the form of an elongate shaft 222, having outwardly extending vanes 224, is disposed in conduit 212, and rotated therein about an axis 226, as by a motor 228, to provide enhanced uniformity of thermal contact between the cool fluid material 210 and the walls of the conduit 212. A preferred type of conduit 212 and agitator 220 are together known as a scraped surface heat exchanger.
Reference is now made to FIG. 3, which is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with still another preferred embodiment of the present invention. As seen in FIG. 3, the vacuum heat exchange system preferably includes a thermally insulated [0137] enclosure 300, the interior of which communicates with the ambient atmosphere via a vacuum pump 302, which preferably maintains the interior of enclosure 300 at subatmospheric pressure, typically about 29″ of mercury.
[0138] Enclosure 300 is partially filled with a cooling liquid 304, preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure 300. A heated fluid material 306, such as a heated food product which has undergone electroheating, is preferably supplied to a conduit 308, which extends through the liquid 304. As the heated fluid material 306 passes through the conduit 308, in thermal contact with the walls thereof, it becomes cooled by evaporating the liquid 304, thereby heating the liquid 304, generating heated vapor 309. The cooled fluid material then flows from the conduit 308.
In accordance with a preferred embodiment of the present invention, an [0139] agitator 310, typically in the form of an elongate shaft 312, having outwardly extending vanes 314, is disposed in conduit 308, and rotated therein about an axis 316, as by a motor 318, to provide enhanced uniformity of thermal contact between the heated fluid material 306 and the walls of the conduit 308. A preferred type of conduit 308 and agitator 310 are together known as a scraped surface heat exchanger.
In accordance with a preferred embodiment of the present invention a [0140] cool fluid material 320, such as a food product which is to be electroheated, is caused to pass through a conduit 322, which extends through enclosure 300, above the level of the cooling liquid 304. The temperature of the cool fluid material 320 is preferably sufficiently low as to cause vapors of the cooling liquid 304 to condense upon contact with the outer walls of conduit 322 and to fall downward into cooling liquid 304, as drops 324. As the cool fluid material 320 passes through the conduit 322, in thermal contact with the walls thereof, it becomes heated by the heated vapor 309 from liquid 304. The heated fluid material then flows from the conduit 322.
In accordance with a preferred embodiment of the present invention, an [0141] agitator 330, typically in the form of an elongate shaft 332, having outwardly extending vanes 334, is disposed in conduit 322, and rotated therein about an axis 336, as by a motor 338, to provide enhanced uniformity of thermal contact between the cool fluid material 320 and the walls of the conduit 322. A preferred type of conduit 322 and agitator 330 are together known as a scraped surface heat exchanger.
Reference is now made to FIG. 4, which is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with a preferred embodiment of the present invention. As seen in FIG. 4, the system and methodology of FIG. 4 typically comprises a [0142] preheating subsystem 400, such as that shown in FIG. 2 and described hereinabove, which receives a fluid material, such as a food product, to be preheated and preheats it to a desired temperature, an electroheater 402, which heats the preheated fluid material to a predetermined temperature for a predetermined time and a cooling subsystem 404, such as that shown in FIG. 1A and described hereinabove, which receives the electroheated fluid material, typically from a holding tank 406, cools the fluid material and supplies it to an aseptic filling mechanism 408 after it has been further cooled in conventional cooler 409, thereby producing a packaged product having new and superior characteristics.
Pre-heating, [0143] subsystem 400 preferably comprises a thermally insulated enclosure 410, the interior of which communicates with the ambient atmosphere via a vacuum pump 412, which preferably maintains the interior of enclosure 410 at subatmospheric pressure, typically about 29″ of mercury.
[0144] Enclosure 410 is partially filled with a liquid 414, preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure 410. A heated liquid 416, such as heated water, is preferably supplied to a conduit 418, preferably a coil, which extends through the liquid 414. As the heated liquid 416 passes through the conduit 418, in thermal contact with the walls thereof, it heats the liquid 414, generating heated vapor 419.
In accordance with a preferred embodiment of the present invention a cool fluid material to be preheated [0145] 420, such as a food product, is caused to pass through a conduit 422, which extends through enclosure 410, above the level of the cooling liquid 414. As the cool fluid material 420 passes through the conduit 422, in thermal contact with the walls thereof, it becomes heated by the heated vapor 419 from liquid 414. The heated fluid material then flows from the conduit 422.
In accordance with a preferred embodiment of the present invention, an [0146] agitator 430, typically in the form of an elongate shaft 432, having outwardly extending vanes 434, is disposed in conduit 422, and rotated therein about an axis 436, as by a motor 438, to provide enhanced uniformity of thermal contact between the fluid material 420 and the walls of the conduit 422. A preferred type of conduit 422 and agitator 430 are together known as a scraped surface heat exchanger.
The pre-heated output of the scraped surface heat exchanger is preferably supplied to [0147] electroheater 402, which is operative to heat the pre-heated fluid material to an elevated temperature in a very short time. Suitable electroheaters are described in applicant's U.S. Pat. Nos. 6,304,718, 6,088,509; 5,863,580; 5,768,472; 5,636,317; 5,609,900; 5,607,613; 5,583,960; 5,415,882; 5,290,583 and 4,739,140, the disclosures of which are hereby incorporated by reference. A preferred embodiment of an electroheater is described hereinbelow with reference to FIG. 7.
The heated output of [0148] electroheater 402 is preferably supplied via a holding tank 406 to cooling subsystem 404. Cooling subsystem 404 preferably comprises a thermally insulated enclosure 440, the interior of which communicates with the ambient atmosphere via a vacuum pump 442, which preferably maintains the interior of enclosure 440 at subatmospheric pressure, typically about 29″ of mercury.
[0149] Enclosure 440 is partially filled with a cooling liquid 444, preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure 440. The electroheated fluid material 446 is preferably supplied to a conduit 448, which extends through the liquid 444. As the electroheated fluid material 446 passes through the conduit 448, in thermal contact with the walls thereof it becomes cooled by evaporating the liquid 444.
In accordance with a preferred embodiment of the present invention, an [0150] agitator 450, typically in the form of an elongate shaft 452, having outwardly extending vanes 454, is disposed in conduit 448, and rotated therein about an axis 456, as by a motor 458, to provide enhanced uniformity of thermal contact between the electroheated fluid material 446 and the walls of the conduit 448. A preferred type of conduit 448 and agitator 450 are together known as a scraped surface heat exchanger.
In accordance with a preferred embodiment of the present invention a cooling liquid [0151] 460, preferably water, is caused to pass through a conduit 462, preferably a coil, which extends through enclosure 440, above the level of the cooling liquid 444. The temperature of the cooling liquid 460 is preferably sufficiently low as to cause vapors of the cooling liquid 444 to condense upon contact with the outer walls of conduit 462 and to fall downward into cooling liquid 444, as drops 464.
The cooled output of [0152] cooling subsystem 404 is preferably supplied to conventional cooler 409 for further cooling prior to being sent to aseptic filling mechanism 408 which produces a packaged product having enhanced shelf life and storage temperature insensitivity.
Reference is now made to FIG. 5, which is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with another preferred embodiment of the present invention. As seen in FIG. 5, the system and methodology of FIG. 5 typically comprises a preheating and cooling vacuum [0153] heat exchange subsystem 500, such as that shown in FIG. 3 and described hereinabove which receives a fluid material, such as a food product, to be preheated and preheats it to a desired temperature, an electroheater 502, which rapidly heats the fluid material to a predetermined temperature for a predetermined time and then supplies it to a holding tank 504 and thence back to subsystem 500 for rapid cooling thereof, and an aseptic filling mechanism 506, which receives the cold fluid material via a conventional cooler 508 and produces a packaged product having new and superior characteristics of shelf life and temperature insensitivity.
As seen in FIG. 5, the vacuum heat exchange system preferably includes a thermally insulated [0154] enclosure 510, the interior of which communicates with the ambient atmosphere via a vacuum pump 512, which preferably maintains the interior of enclosure 510 at subatmospheric pressure, typically about 29″ of mercury.
[0155] Enclosure 510 is partially filled with a cooling liquid 514, preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure 510.
In accordance with a preferred embodiment of the present invention a [0156] fluid material 520, such as a food product which is to be electroheated, is caused to pass through a conduit 522, which extends through enclosure 510, above the level of the cooling liquid 514. The temperature of the fluid material 520 is preferably sufficiently low as to cause vapors of the cooling liquid 514 to condense upon contact with the outer walls of conduit 522 and to fall downward into cooling liquid 514, as drops 524. As the cool fluid material 520 passes through the conduit 522, in thermal contact with the walls thereof, it becomes heated by the heated vapor 526 from liquid 514. The heated fluid material then flows from the conduit 522.
In accordance with a preferred embodiment of the present invention, an [0157] agitator 530, typically in the form of an elongate shaft 532, having outwardly extending vanes 534, is disposed in conduit 522, and rotated therein about an axis 536, as by a motor 538, to provide enhanced uniformity of thermal contact between the fluid material 520 and the walls of the conduit 522. A preferred type of conduit 522 and agitator 530 are together known as a scraped surface heat exchanger.
The preheated output of [0158] conduit 522 is preferably supplied to electroheater 502, which is operative to heat the pre-heated fluid material to an elevated temperature in a very short time. Suitable electroheaters are described in applicant's U.S. Pat. Nos. 6,304,718; 6,088,509; 5,863,580; 5,768,472; 5,636,317; 5,609,900; 5,607,613; 5,583,960; 5,415,882; 5,290,583 and 4,739,140, the disclosures of which are hereby incorporated by reference. A preferred embodiment of an electroheater is described hereinbelow with reference to FIG. 7.
The heated output of [0159] electroheater 502 is preferably supplied via holding tank 504 and a pump 540 to a conduit 542, which extends through the liquid 514. As the heated fluid material passes through the conduit 542, in thermal contact with the walls thereof, it becomes cooled by evaporating the liquid 514.
In accordance with a preferred embodiment of the present invention, an [0160] agitator 550, typically in the form of an elongate shaft 552, having outwardly extending vanes 554, is disposed in conduit 542, and rotated therein about an axis 556, as by a motor 558, to provide enhanced uniformity of thermal contact between the heated fluid material and the walls of the conduit 542. A preferred type of conduit 542 and agitator 550 are together known as a scraped surface heat exchanger.
[0161] Aseptic filling mechanism 506 receives the cooled fluid material from conduit 542 after it has been further cooled in conventional cooler 508 and produces a packaged product having new and superior characteristics of shelf life and temperature insensitivity.
Reference is now made to FIG. 6, which is a temperature-time graph illustrating operation of the present invention for processing food products, such as humus, in accordance with preferred embodiments of the present invention, such as those shown and described hereinabove with particular reference to FIGS. 4 and 5. [0162]
As seen in FIG. 6, the food product is rapidly preheated by the first heat exchanger, such as heat exchanger [0163] 400 (FIG. 4) or 500 (FIG. 5), typically from a temperature of 40 degrees C. to a temperature of 85 degrees C. in approximately 40 seconds. Thereafter, the food product is heated to about 130 degrees C. by the electroheater, such as electroheater 402 (FIG. 4) or 502 (FIG. 5), in a fraction of a second. It is then cooled to a temperature of 85 degrees C. by the vacuum heat exchanger, such as heat exchanger 404 (FIG. 4) or 500 (FIG. 5), in approximately 40 seconds, after being held for a period of time in a holding tank at 130 degrees C. It is then preferably cooled further from a temperature of 85 degrees C. to approximately 40 degrees C. or below before being aseptically packaged.
It has been found by the applicant that humus which has been sterilized by rapid heating and cooling as described hereinabove is characterized by having extremely long shelf life without requiring refrigeration and by having substantial tolerance to temperature abuse. [0164]
It has also been found by the applicant that liquid egg which has been pasteurized by rapid heating, typically to temperatures in the range of 75-85 degrees C., and cooling, similar to that described hereinabove, is characterized by having extremely long refrigerated shelf life and by having tolerance to temperature abuse. [0165]
Reference is now made to FIG. 7, which is a simplified illustration of an electroheater which is particularly suitable for use with viscous products, such as humus. As seen in FIG. 7, a viscous product, such as humus, typically having a viscosity in the range of 20,000 centipoise is supplied at a high rate, typically in the range of 1,500 to 5,000 liters/hour through an electrically [0166] insulative conduit 700, in the direction indicated by arrows 702.
Three conductive electrodes, [0167] 704, 706 and 708 are preferably arranged in spaced mutual arrangement along conduit 700. Each electrode preferably includes a hollow disc, the interior of which communicates with the interior of conduit 700 by means of a plurality of downstreamly directed angled openings 710. A relatively small quantity of a conductive fluid, typically 1 to 5 liters/hour per electrode, is supplied to conduit 700 from supply conduits 712, 714 and 716, which output to respective electrodes 704, 706 and 708 and thence via openings 710 to conduit 700. It is seen that preferably electrodes 704 and 708 are grounded, while electrode 706 receives AC current at high voltage, preferably at mains frequencies.
The arrangement of FIG. 7 is preferred for electroheating of relatively viscous materials, since it generally prevents physical contact between the viscous materials and [0168] electrodes 704, 706 and 708. Also, there are no obstacles to flow and no change of diameter, so the velocity is high and uniform.
Reference is now made to FIG. 8, which is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with yet another preferred embodiment of the present invention. [0169]
As seen in FIG. 8, the material treatment system and methodology of FIG. 8 employs a thermally insulated [0170] enclosure 800, the interior of which is in communication with the ambient atmosphere via a vacuum pump 802, which preferably maintains the interior of enclosure 800 at subatmospheric pressure, typically about 29″ of mercury.
[0171] Enclosure 800 is partially filled with a cooling liquid 804, preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure 800. A scraped surface heat exchanger 806 is disposed in enclosure 800 and includes a conduit 808, part of which extends through the liquid 804. Heated fluid material 810, such as an electroheated food product, passes through the conduit 808, in thermal contact with the walls thereof, and becomes cooled by evaporating the liquid 804.
In accordance with a preferred embodiment of the present invention, an [0172] agitator 812, typically in the form of an elongate shaft 814, having outwardly extending vanes 816, is disposed in conduit 808, and rotated therein about an axis 818, as by a motor 820, to provide enhanced uniformity of thermal contact between the heated fluid material 810 and the walls of the conduit 808.
Disposed inside [0173] enclosure 800 above the level of the cooling liquid 804 is a condensing coil 822. A coolant, such as water, preferably passes through condensing coil 822.
The system of FIG. 8 also preferably comprises a [0174] reservoir 824 in fluid communication with the interior of enclosure 800, such as by means of a flexible tube 826. Reservoir 824 preferably contains cooling liquid 804 which can flow into the interior of enclosure 800 via flexible tube 826. Another flexible tube 828 is preferably provided to ensure that the vacuum maintained inside enclosure 800 is also maintained inside reservoir 824. Reservoir 824 is preferably mounted onto a vertical track (not shown) for selectable vertical positioning relative to enclosure 800, thereby to enable ease of selection of the level of cooling liquid 804 in enclosure 800. This level effectively controls the amount of cooling produced by the system by determining how much of the scraped surface heat exchanger 806 is disposed in the liquid 804.
It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art. [0175]

Claims

1. A vacuum heat exchange system comprising:

a container partially filled with a liquid and maintained under a vacuum;

a first heat exchanger disposed in said liquid in said container, said first heat exchanger receiving a first fluid material, heating said liquid and thereby cooling said first fluid material; and

a second heat exchanger disposed outside of said liquid in said container, said second heat exchanger receiving a second fluid material and being heated by vapors of said liquid thereby heating said second fluid material,

at least one of said first and second heat exchangers including an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

2. A vacuum heat exchange system according to claim 1 and wherein both of said first and second heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

3. A vacuum heat exchange system according to claim 1 and wherein first heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchange generally throughout said first fluid material.

4. A vacuum heat exchange system according to claim 1 and wherein second heat exchanger includes an agitator for agitating said second fluid material passing therethrough to enhance heat exchange generally throughout said second fluid material.

5. A vacuum heat exchange system according to claim 1 and wherein at least one of said first and second heat exchangers comprises a scraped surface heat exchanger.

6. A vacuum heat exchange system according to claim 1 and also comprising:

an electroheater for heating said first fluid material prior to receipt thereof by said first heat exchanger.

7. A vacuum heat exchange system according to claim 1 and also comprising:

an electroheater for receiving said second fluid material from said second heat exchanger.

8. A vacuum heat exchange system according to claim 1 wherein said first and second fluid materials are the same material at different temperatures and also comprising:

an electroheater for heating said first fluid material prior to receipt thereof by said first heat exchanger and wherein said first fluid material is received by said electroheater from said second heat exchanger.

9. A vacuum heat exchange system according to claim 2 wherein said first and second fluid materials are the same material at different temperatures and also comprising:

10. A vacuum heat exchange system according to claim 5 wherein said first and second fluid materials are the same material at different temperatures and also comprising:

11. A material treatment system comprising:

an electroheater operative to rapidly heat a first fluid material; and

a vacuum heat exchange subsystem operative to rapidly cool said first fluid material following electroheating thereof, said vacuum heat exchange subsystem comprising:

a container partially filled with a liquid and maintained under a vacuum;

a first heat exchanger disposed in said liquid in said container, said first heat exchanger receiving said first fluid material, heating said liquid and thereby cooling said first fluid material, and

a second heat exchanger disposed outside of said liquid in said containers said second heat exchanger receiving a second fluid material and being heated by vapors of said liquid, thereby heating said second fluid material,

12. A material treatment system according to claim 11 and wherein both of said first and second heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

13. A material treatment system according to claim 11 and wherein first heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchange generally throughout said first fluid material.

14. A material treatment system according to claim 11 and wherein second heat exchanger includes an agitator for agitating said second fluid material passing therethrough to enhance heat exchange generally throughout said second fluid material.

15. A material treatment system according to claim 11 and wherein at least one of said first and second heat exchangers comprises a scraped surface heat exchanger.

16. A material treatment system according to claim 11 and wherein said electroheater supplies said first fluid material to a holding tank, prior to receipt of said first fluid material by said first heat exchanger.

17. A material treatment system according to claim 11 and wherein said electroheater receives said second fluid material from said second heat exchanger.

18. A material treatment system according to claim 11 wherein said first and second fluid materials are the same material at different temperatures and wherein said electroheater heats said first fluid material prior to receipt thereof by said first heat exchanger and wherein said first fluid material is received by said electroheater from said second heat exchanger.

19. A material treatment system according to claim 12 wherein said first and second fluid materials are the same material at different temperatures and wherein said electroheater heats said first fluid material prior to receipt thereof by said first heat exchanger and wherein said first fluid material is received by said electroheater from said second heat exchanger.

20. A material treatment system according to claim 15 wherein said first and second fluid materials are the same material at different temperatures and wherein said electroheater heats said first fluid material prior to receipt thereof by said first heat exchanger and wherein said first fluid material is received by said electroheater from said second heat exchanger.

21. A material treatment system comprising:

an electroheater operative to rapidly heat a first fluid material;

a first vacuum heat exchange subsystem operative to rapidly cool said first fluid material following electroheating thereof, said first vacuum heat exchange subsystem comprising:

a container partially filled with a liquid and maintained under a vacuum;

a first heat exchanger disposed in said liquid in said container, said first heat exchanger receiving said first fluid material, heating said liquid and thereby cooling said first fluid material; and

a second heat exchanger disposed outside of said liquid in said container said second heat exchanger receiving a second fluid material and being heated by vapors of said liquid, thereby heating said second fluid material,

at least one of said first and second heat exchangers including an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material; and

a second vacuum heat exchange subsystem operative to preheat said first fluid material prior to electroheating thereof, said second vacuum heat exchange subsystem comprising:

a container partially filled with a liquid and maintained under a vacuum;

a third heat exchanger disposed in said liquid in said container, said third heat exchanger receiving a third fluid material, heating said liquid and thereby cooling said third fluid material; and

a fourth heat exchanger disposed outside of said liquid in said container, said fourth heat exchanger receiving said first fluid material and being heated by vapors of said liquid, thereby heating said first fluid material,

at least one of said third and fourth heat exchangers including an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

22. A material treatment system according to claim 21 and wherein both of said first and second heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

23. A material treatment system according to claim 21 and wherein first heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchange generally throughout said first fluid material.

24. A material treatment system according to claim 21 and wherein second heat exchanger includes an agitator for agitating said second fluid material passing therethrough to enhance heat exchange generally throughout said second fluid material.

25. A material treatment system according to claim 21 and wherein at least one of said first and second heat exchangers comprises a scraped surface heat exchanger.

26. A material treatment system according to claim 21 and wherein said electroheater supplies said first fluid material to a holding tank, prior to receipt of said first fluid material by said first heat exchanger.

27. A material treatment system according to claim 21 and wherein both of said third and fourth heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

28. A material treatment system according to claim 21 and wherein third heat exchanger includes an agitator for agitating said third fluid material passing therethrough to enhance heat exchange generally throughout said third fluid material.

29. A material treatment system according to claim 21 and wherein fourth heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchange generally throughout said first fluid material.

30. A material treatment system according to claim 21 and wherein at least one of said third and fourth heat exchangers comprises a scraped surface heat exchanger.

31. A packaged food product characterized in:

having a viscosity exceeding approximately 5,000 centipoise;

being sterilized; and

being aseptically packaged.

32. A packaged food product according to claim 31 and having a pH exceeding approximately 4.5.

33. A packaged humus food product characterized in:

being sterilized; and

being aseptically packaged.

34. A packaged egg food product characterized in:

being sterilized; and

being aseptically packaged.

35. A packaged egg food product characterized in:

being sterilized;

36. A packaged egg food product according to claim 34 and wherein said egg food product is coagulated.

37. A packaged egg food product according to claim 35 and wherein said egg food product is coagulated.

38. A packaged egg food product characterized in:

being pasteurized to at least 75 degrees Centigrade;

being liquid.

39. A vacuum heat exchange method comprising:

partially filling a container maintained under a vacuum with a liquid;

receiving a first fluid material in a first heat exchanger disposed in said liquid in said containers heating said liquid and thereby cooling said first fluid material; and

receiving a second fluid material in a second heat exchanger disposed outside of said liquid in said container, heating said second heat exchanger by vapors of said liquid, thereby heating said second fluid material,

where at least one of said first and second heat exchangers includes an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

40. A vacuum heat exchange method according to claim 39 and wherein both of said first and second heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

41. A vacuum heat exchange method according to claim 39 and wherein first heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchange generally throughout said first fluid material.

42. A vacuum heat exchange method according to claim 39 and wherein second heat exchanger includes an agitator for agitating said second fluid material passing therethrough to enhance heat exchange generally throughout said second fluid material.

43. A vacuum heat exchange method according to claim 39 and wherein at least one of said first and second heat exchangers comprises a scraped surface heat exchanger.

44. A vacuum heat exchange method according to claim 39 and also comprising:

heating said first fluid material in an electroheater prior to receipt thereof by said first heat exchanger.

45. A vacuum heat exchange method according to claim 39 and also comprising:

receiving said second fluid material into an electroheater from said second heat exchanger.

46. A vacuum heat exchange method according to claim 39 wherein said first and second fluid materials are the same material at different temperatures and also comprising:

receiving said first fluid material from said second heat exchanger; and

heating said first fluid material using an electroheater prior to receipt thereof by said first heat exchanger.

47. A vacuum heat exchange method according to claim 40 wherein said first and second fluid materials are the same material at different temperatures and also comprising:

receiving said first fluid material from said second heat exchanger; and

48. A vacuum heat exchange method according to claim 43 wherein said first and second fluid materials are the same material at different temperatures and also comprising:

receiving said first fluid material from said second heat exchanger; and

49. A material treatment method comprising:

rapidly heating a first fluid material using an electroheater; and

rapidly cooling, said first fluid material following electroheating thereof by:

partially filling a container maintained under a vacuum with a liquid;

receiving said first fluid material in a first heat exchanger disposed in said liquid in said container, heating said liquid and thereby cooling said first fluid material; and

50. A material treatment method according to claim 49 and wherein both of said first and second heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

51. A material treatment method according to claim 49 and wherein first heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchange generally throughout said first fluid material.

52. A material treatment method according to claim 49 and wherein second heat exchanger includes an agitator for agitating said second fluid material passing therethrough to enhance heat exchange generally throughout said second fluid material.

53. A material treatment method according to claim 49 and wherein at least one of said first and second heat exchangers comprises a scraped surface heat exchanger.

54. A material treatment method according to claim 49 and comprising:

supplying said first fluid material to a holding tank from said electroheater prior to receiving said first fluid material in said first heat exchanger.

55. A material treatment method according to claim 49 and comprising:

receiving said second fluid material into said electroheater from said second heat exchanger.

56. A material treatment method according to claim 49 wherein said first and second fluid materials are the same material at different temperatures and comprising:

receiving said first fluid material by said electroheater from said second heat exchanger; and

heating said first fluid material in said electroheater prior to receipt thereof by said first heat exchanger.

57. A material treatment method according to claim 50 wherein said first and second fluid materials are the same material at different temperatures and comprising:

58. A material treatment method according to claim 53 wherein said first and second fluid materials are the same material at different temperatures and comprising:

59. A material treatment method comprising:

rapidly heating a first fluid material using an electroheater; and

rapidly cooling said first fluid material following electroheating thereof by:

partially filling a container maintained under a vacuum with a liquid;

receiving a first fluid material in a first heat exchanger disposed in said liquid in said container, heating said liquid and thereby cooling said first fluid material; and

where at least one of said first and second heat exchangers includes an agitator for agitating said fluid material passing therethrough to enhance heat exchanger generally throughout said fluid material; and

preheating said first fluid material prior to electroheating thereof by:

partially filling a container maintained under a vacuum with a liquid;

receiving a third fluid material in a third heat exchanger disposed in said liquid in said container, heating said liquid and thereby cooling said third fluid material; and

receiving said first fluid material in a fourth heat exchanger disposed outside of said liquid in said container, heating said fourth heat exchanger by vapors of said liquid, thereby heating said first fluid material,

where at least one of said third and fourth heat exchangers includes an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

60. A material treatment method according to claim 59 and wherein both of said first and second heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

61. A material treatment method according to claim 59 and wherein first heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchanger generally throughout said first fluid material.

62. A material treatment method according to claim 59 and wherein second heat exchanger includes an agitator for agitating said second fluid material passing therethrough to enhance heat exchange generally throughout said second fluid material.

63. A material treatment method according to claim 59 and wherein at least one of said first and second heat exchangers comprises a scraped surface heat exchanger.

64. A material treatment method according to claim 59 and comprising:

65. A material treatment method according to claim 59 and wherein both of said third and fourth heat exchangers include an agitator for agitating said fluid material passing therethrough to enhance heat exchange generally throughout said fluid material.

66. A material treatment method according to claim 59 and wherein third heat exchanger includes an agitator for agitating said third fluid material passing therethrough to enhance heat exchange generally throughout said third fluid material.

67. A material treatment method according to claim 59 and wherein fourth heat exchanger includes an agitator for agitating said first fluid material passing therethrough to enhance heat exchange generally throughout said first fluid material.

68. A material treatment method according to claim 59 and wherein at least one of said third and fourth heat exchangers comprises a scraped surface heat exchanger.

69. A method of preparing a packaged food product comprising:

sterilizing said food product; and

aseptically packaging said food product.

70. A method of preparing a packaged food product according to claim 69 and wherein said packaged food product has a pH exceeding approximately 4.5.

71. A method of preparing a packaged humus food product comprising:

sterilizing said humus food product; and

aseptically packaging said humus food product.

72. A method of preparing a packaged egg food product comprising:

sterilizing said egg food product; and

aseptically packaging said egg food product.

73. A method of preparing a packaged egg food product comprising:

sterilizing said egg food product;

cooling said egg food product: and

aseptically filling and sealing said egg food product in a package.

74. A method of preparing a packaged egg food product according to claim 72 and wherein said egg food product is coagulated.

75. A method of preparing a packaged egg food product according to claim 73 and wherein said egg food product is coagulated.

76. A method of preparing a packaged liquid egg food product comprising:

pasteurizing said liquid egg food product to at least 75 degrees Centigrade;

cooling said liquid egg food product; and

aseptically filling and sealing said liquid egg food product in a package.