US20150330722A1

US20150330722A1 - Method and device for internal accumulation and circulation of thermally treated fluid

Info

Publication number: US20150330722A1
Application number: US14/651,138
Authority: US
Inventors: Francesco Loddo
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-12-11
Filing date: 2013-12-11
Publication date: 2015-11-19
Also published as: EP2941599B1; EP2941599C0; EP2941599A1; WO2014091421A1; CN104956156A

Abstract

A device adapted to accumulate a thermally treated includes: a containment chamber of the thermally treated fluid (1), at least one separator (4) arranged with a substantially vertical development in the containment chamber, at least one separator being adapted to divide the chamber in at least two parts, and to leave openings at the opposite upper (6) and lower (7) end of the chamber, by means of which the fluid can pass in order to determine a rotatory circulation of the fluid in the cross direction in the chamber.

Description

APPLICATION FIELD OF THE INVENTION

The present invention refers to the field of the systems for the thermal treatment of the fluids, and more precisely to a method and device for the internal accumulation and circulation of thermally treated fluid.

DESCRIPTION OF THE PRIOR ART

Different types of devices are known for the accumulation of thermally treated fluid, characterized by different configurations, that can be classified essentially in the vertical-axis or horizontal-axis types, fed by different thermal exchange systems, such as coils, fluid or electric heat exchangers.
Such known configurations, regardless of the volume and of the type of plant where the system is used, involve problems of relevant thermal inertia. The larger is the volume of the accumulation, the slower will be the process to reach the suitable temperature.
Furthermore, in these known devices, a considerable thermal stratification in vertical direction of the fluid they contain is generated, so that the fluid tends to have a much higher temperature in the upper region compared to the one of the lower region of the device itself. The high temperature gradient in vertical direction limits: the possibility of using the fluid; the volume available at the highest temperature set in the system; furthermore recovering the suitable temperature is harder, once it lowered due either to the process consumption or to the natural mixing because of the internal gradient.
Furthermore, in the devices known a high internal turbulence develops during the step of thermal accumulation, which slows down the process of reaching the suitable temperature.
The phenomena described above are particularly relevant in the current types of tanks equipped with a single chamber geometry.

SUMMARY OF THE INVENTION

Therefore the aim of the present invention is to provide a method and a device for the internal accumulation and circulation of thermally treated fluid, adapted to overcome all the aforementioned drawbacks, allowing to improve the efficiency of the heat exchange, regardless of whether the energy is added or removed, and to increase the uniformity of the internal temperature of the device.
The accumulation system of the present invention determines a kinetics of the fluid that remarkably reduces the turbulences, thus the flow resistance, allowing a remarkable improvement of the energy efficiency, consequently making the operation faster, an almost constant temperature throughout the whole available volume, a very slow thermal decay due to the high temperature uniformity obtained by the system, and thus a relevant overall money saving.
This result is obtained by constraining the motion of the fluid to be thermally treated in a chamber having a substantially horizontal or vertical axis, and wherein the thermal exchange engine system is asymmetric with respect to the vertical medial plane (polar). The chamber is divided into two or more parts by means of the internal interposition of one or more separators or bulkheads having a substantially vertical development, creating an internal circulation. This operating technique allows to create a cross rotatory motion of the fluid within the chamber, regardless of the direction of the rotation (clockwise or counter-clockwise) accelerating the process of fluid mixing. The system according to the invention operates regardless of the source that increases or decreases the temperature of the fluid, namely heating or cooling.
It is object of the present invention a device adapted to accumulate the thermally treated fluid, comprising: a containment chamber of said thermally treated fluid, at least one separator arranged with a substantially vertical development in the containment chamber, said at least one separator being adapted to divide said chamber in at least two parts, and to leave openings at the opposite upper and lower end of said chamber, the fluid being able to pass through it in order to determine a rotatory circulation of the fluid in the cross direction in said chamber.
Preferably said device further comprises at least one heat exchange element arranged in the containment chamber, in one of said parts of the chamber.
A method for using said device is also object of the present invention.
It is a particular object of the present invention a method and a device for the internal accumulation and circulation of thermally treated fluid, as described in the claims that are an integral part of the present description.

BRIEF DESCRIPTION OF THE FIGURES

Further aims and advantages of the present invention will become more apparent from the following detailed description of an embodiment thereof (and of its alternative embodiments) and from the annexed drawings, which are supplied by way of non-limiting example, wherein:

FIGS. from 1 to 7 show some of the possible alternative shapes of the cross section of the device that is object of the present description, in case of a substantially vertical development;

FIGS. 8 and 9 show further possible alternative shapes of the cross section of the device that is object of the present description, in case of a substantially horizontal development;

FIG. 10 shows a further alternative embodiment of the device that is object of the present invention, in case of a furnace, in a cross section view;

FIGS. 11 and 12 show trends in time of the temperature in test conditions of a device of the type known in the art and of a device according to the invention, respectively;

FIG. 13 shows a further embodiment of the device, in a cross section view and in a C-C section view;

FIGS. from 14 to 23 show some of the possible further alternative shapes of the cross section of the device that is object of the present invention;

FIG. 24 shows a lateral axonometric projection of an embodiment of the device;

FIGS. from 25 to 29 show some of the possible further alternative shapes of the cross section of the device that is object of the present invention;

FIG. 30 shows an exploded, perspective view of a boiler with burner according to further alternative embodiments of the present invention;

FIG. 31 shows an assembled, perspective view and a partial internal view of the boiler with burner of FIG. 30;

FIG. 32 shows an example of eccentric section of the furnace of the boiler of FIG. 30.

The same reference numbers and letters in the figures identify the same elements or components.

DETAILED DESCRIPTION OF EMBODIMENTS

FIGS. from 1 to 4 show first embodiments of the device according to the invention which have a substantially cylindrical containment chamber with vertical development 1, equipped with an inlet or outlet duct 2 of the fluid through the lower wall and an inlet or outlet duct of the fluid through the upper wall.
In the chamber, a separator (or bulkhead) 4 is arranged, having a substantially vertical development, in central position, which is connected to the lateral walls of the chamber, but which leaves two openings at the upper (6) and lower (7) opposite ends of the chamber, through which the fluid which fills the chamber can pass. The chamber is shown according to two central section views orthogonal to each other, A-A and B-B respectively, in order to show the separator 4 in a side view (FIGS. 1 and 2) and in a front view (FIGS. 3 and 4).
Furthermore, at least one heat exchange element 5 is present in the chamber, completely arranged on one side of the chamber with respect to the vertical plane of symmetry of the chamber itself. The heat exchange element 5 can be of different shapes and types, which will be described better below, also as a function of the volume of fluid treated and of the temperature that has to be obtained.
By arranging the heat exchange element 5 only on one side of the chamber a cross rotatory motion of the fluid within the chamber is generated (FIGS. 1 and 2), through the two upper and lower openings left by the separator: see arrows 8 indicating the movement of the fluid through the openings and arrows 9 indicating the movement of the fluid in the two opposite directions in the chamber with respect to the separator.
This cross circulation accelerates the mixing process of the fluid, generating a substantial temperature uniformity of the fluid itself within the chamber, both during the heat exchange and at the end of it. This effect is obtained for the heat exchange both decreasing and increasing the temperature. The direction of rotation of the fluid depends on the side where the heat exchange element is present and on whether the exchange decreases or increases the temperature, taking into account that the natural circulation of the fluid moves upwards when the temperature is increasing and downwards when the temperature is decreasing. The variation of the temperature value of an accumulation obtained in such a way is very slow, due to the fact that the temperatures are substantially uniform in the whole volume of the chamber.
In case of a heat exchange increasing the temperature, it is preferable that the fluid is introduced through the duct 2 in the lower part, while the fluid outlet is through the duct 3 in the upper part of the chamber, while in case of a heat exchange reducing the temperature the situation is opposite.
The configuration of the chamber, and thus of both its internal and external walls can be cylindrical, as said above, but also other shapes are possible, for example ovoid, polygonal, namely parallelepiped with or without chamfered angles, or also further shapes.
More than one heat exchange element is present, provided that they are on the same side of the chamber with a single separator. The type of heat exchange can be of different nature (electric or thermal fluid or other), while the desired treatment speed is directly connected to the number of heat exchangers and to their specific power (the volume of the fluid to be treated being the same). The power source of the heat exchangers can be of any type. For example, in a biogas plant, the device of the invention prevents the generation of CO₂
In the FIGS. from 1 to 4, a heat exchanger 5 of the fluid to fluid type is provided.
FIGS. from 5 to 7 show other embodiments of the device according to the invention, with a substantially cylindrical containment chamber 1 having vertical development, wherein the heat exchange in the chamber occurs by means of one or more resistors.
In particular, FIG. 5 shows a resistor heat exchanger 51, on one side of the chamber, preferably having vertical development, on one side of a separator 4. The chamber is equipped with a first inlet or outlet duct 52 of the fluid through the lower wall and it is also equipped with a second inlet or outlet duct 53 of the fluid through the lower wall, whose fluid intake is inside the chamber in the upper part. This configuration is typical of an electric boiler.
Arrows 8 and 9 show the fluid circulation inside the chamber, as in the embodiments of the previous figures.
FIGS. 6 and 7 show further alternative embodiments of the same type as of FIG. 5, but they have two internal parallel separators 41 and 42, which then divide the chamber 1 into three parts. The chamber 1 is always provided with a first inlet or outlet duct, 63 in FIGS. 6 and 73 in FIG. 7, of the fluid through the lower wall and with a second inlet or outlet duct, 64 in FIGS. 6 and 77 in FIG. 7, of the fluid through the upper wall, whose fluid intake is inside the chamber in the upper part.
In the alternative embodiment of FIG. 6, two resistor heat exchangers 61 and 62 are shown, preferably having a vertical development, in the lateral parts of the three parts in which the chamber is divided, while in the alternative embodiment of FIG. 7 two resistor heat exchangers 71 and 72 are shown, preferably having a vertical development, in the middle part of the three parts in which the chamber is divided. Arrows show the directions of internal circulation of the fluid, that, in these cases, since it is a heat exchange increasing the temperature, moves upwards in the parts of the chamber when the exchangers are present, and downwards in the other parts where there are no exchangers.
FIG. 8 shows a further alternative embodiment of the device of the invention, with a containment chamber having a substantially horizontal and cylindrical development 81, in longitudinal and cross section views, wherein the heat exchange in the chamber takes place by means of a heat exchanger 82, for example of the fluid to fluid type, preferably having a horizontal development.
The exchanger 82 is placed on one side of the chamber, laterally to a separator 43. The chamber is provided with a first inlet or outlet duct 83 of the fluid through a lateral wall and it is also equipped with a second inlet or outlet duct 84 of the fluid through said lateral wall, whose fluid intake is inside the chamber in the opposite part.
The separator 43 is placed centrally in the chamber with a substantially vertical direction, and develops along the medial horizontal direction of the chamber between the two opposite walls, and has two series of slots, on the upper 85 and lower 86 edges, respectively. The slots ensure the passage of the fluid through them, in order to create a cross circulation of the fluid in the chamber, as indicated by the directions of the arrows.
In case of a heat exchange increasing the temperature, on the side of the chamber where the exchanger 82 is present the direction of the fluid is from the bottom upwards, in the opposite direction in the other side of the chamber.
FIG. 9 shows different possible shapes of the cross section of a chamber having a horizontal direction, of the same type as the one of FIG. 8. In each of the shapes, the presence of a separator can be noticed in median position in a substantially vertical direction, having several shapes, not only straight, but also possibly slightly curved, in order to ensure enough space for positioning one or more heat exchangers on one side of the chamber. The presence of the upper and lower slots of the separators in order to guarantee the cross circulation of the fluid in the chamber can be noticed.
Furthermore, in the different embodiments of the present invention, with the chamber having a substantially vertical or horizontal axis, the separator (or bulkhead) 4 can have an elongated cross section configuration, not always straight, but having also a different shape, for example curved, as shown in FIG. 13. Here the configuration of the separator 4 is such as to allow the insertion in the chamber 1 of a heat exchanger 5, for example having a horizontal development. It can be seen that the separator 4 is connected to the side walls of the chamber 1, while it leaves two openings at the opposite ends 6, 7 of the chamber, through which the fluid can pass (arrows 8). The separator divides the chamber in two equal or different volumes, one volume housing one or more heat exchangers, also of various type.
In the various embodiments of the present invention, the width of the openings 6, 7 at the ends of the chamber is determined in order to ensure a correct and efficient fluid circulation, also in terms of its speed, and it can also depend on the density of the fluid and on its composition, and it can further depend on the presence of mixing substances therein.
With reference to FIG. 10, in a further alternative embodiment of the present invention, an example of application with fluid air can be represented by a stove for cooking food or other substances, for example ceramic elements. In any case, a high temperature and a uniformity of the latter are essential factors for the success of the final product.
In FIG. 10, the stove 101, in a cross section view, has substantially an external wall 102 and an internal chamber 103. In the internal chamber, an internal separator is present 104, having a substantially vertical development, in an intermediate position, such as to divide the internal space of the stove into two parts. In the upper part, the separator leaves an internal opening 105, as in the lower part of the stove (opening 108). In the stove, one or more horizontal grills 106 are present, as a support for the elements to be cooked. In one of the two parts of the chamber delimited by the intermediate separator 104, one or more series of heating elements 107 are present, possibly comprised in the support grills. Grills are openwork to let the air pass through them. The heating elements can be power supplied in various ways, for example electrically. In the area of the bottom opening 108 a fan 110 can be present as a system to force the circulation of the air in order to accelerate the thermal flow. Downstream of the bottom opening 108, a compensation chamber 111 can be present to allow an effective distribution of the air in any operating space of the cooking chambers.
Due to the presence of the separator 104, of the two upper 105 and lower 108 openings, and of the heating elements 107 in a part of the camera, an air circulation within the camera is generated, shown by the arrows in the figure. Since the heat exchange is of the type increasing the temperature, on the side of the chamber where the exchanger 107 is present the direction of the fluid is from the bottom upwards, in the opposite direction in the other side of the chamber.
In the lower part of the stove, a bottom hopper 109 is possibly present, which has the twofold function of air conveyor and accumulator and outlet of dust and working debris which the workflow can determine.
In the various embodiments described above the device that is object of the invention appears as a container closed by opposite walls, which can be inserted in any installation for the thermally treatment of the fluids. It must be equipped with appropriate valves and/or intakes and withdrawal taps of the fluid from the annular chambers, and with connections of the heat exchangers to the respective energy sources. The person skilled in the art is able to realize the installation and its connections by applying the normal technique known in the art.
In the simplest configuration of the installation, the heat exchangers are configured as simple through pipes, for example fixed to the end walls of the annular chambers; their number depends on the speed and on the uniformity of functional heating of the productive cycle.
The exchangers may have linear or non-linear shapes, coils, corrugated or finned fluid heat exchangers supplied by a heat source selected according to their use or their needs, for example, electric, fluid thermal, also with a renewable energy source, for example solar, etc. . . . .
The heat exchangers can be positioned in a fixed or extractable version depending on production and/or maintenance needs.
The thermal vector or type of fluid selected to be inside the exchangers depends on the industrial process wherein the present invention is applied, as well as on its degree of viscosity. The material which the device is made of and/or is covered with is also a function of the chemical aggressiveness of the liquids treated and thus of their dangerousness.
There are no specific limits for the type of fluid to be treated: further constructive differentiations that will be realized will be directly connected to the type of technological process where it will be used.
FIGS. 11 and 12 show diagrams of the temperature increase trend between a device according to the invention (FIG. 12) and a device of the type known in the art (FIG. 11), in an experiment carried out in equivalent conditions of heating duration (60 min.), quantity of fluid treated, initial temperature of the fluid (about 18° C.), external ambient temperature (about 20° C.), shape of the vertical container, drawn as a background in the figures.
The temperature is measured by thermal probes in three points of the container, in the upper part (point 113 in FIG. 11, point 123 in FIG. 12), in the intermediate part (point 112 in FIG. 11, point 122 in FIG. 12), and in the lower part (point 111 in FIG. 11, point 121 in FIG. 12), respectively. It can be seen that after 60 min. the temperature on the upper part of the two containers is similar (about 63-64° C.) with a linear trend, as well as in the intermediate part (about 61-62° C.), while in the device according to the invention, the temperature in the lower part (about 57° C.) reaches almost the one in the upper part with a linear trend, while in the device known in the art, the temperature remains at a low value (about 33° C.), with a slow increase trend.
It will be apparent to the person skilled in the art that other equivalent embodiments, and their combinations, of the invention can be conceived and reduced to practice without departing from the scope of the invention.
The separator can be a simple plate, for example made of metal or of other material, for example teflon, or an element comprising an insulation, for a better thermal separation between the parts which the internal chamber is divided in.
The thermal fluid can be of various type, not only water, but also other chemical substances, e.g. wine, grape must, milk, beer, fruit juices, and/or liquids from the chemical or petrochemical industry, or containing animal or vegetal waste, possibly pre-treated. Thus the device of the invention can be advantageously used in a system for food production or treatment, for example in the process of making wine or beer.
The effect of cross circulation of the fluid can exist also when the internal heat exchanger is not present. For example in case of non-insulated external walls, it is possible to obtain an effect of internal heating by solar irradiation, and, consequently, by the effect of cross circulation of the fluid.
The advantages deriving from the application of the present invention are evident.
The device allows to obtain a fast and efficient thermal uniformity, both for heating and for cooling, with respect to the traditional accumulation boilers currently used in the different production cycles.
Extremely more efficient results can be obtained both in the heating step and in the settling step of the temperature of the process, by using, in fact, lower peak internal temperatures or anyway for a definitely shorter time than the traditional systems.
Both constant and variable annular sections can be used, depending on the fact that the speed of the operating process to optimize the conditioned volume or the temperature variation is exploited.
The configuration of the annular chamber eliminates turbulence and inertia that makes the process of starting-up temperature of the volume of fluid to be processed very slow. The heating speed and the stratification of the fluid contained in the annular chamber will be connected to the number and to the section of the heat exchangers that will be placed within the system.
The system allows to obtain a remarkable energy saving regardless of the vector fluid and of the liquid that one wants to condition, also due to the possibility of setting lower maximum temperatures than the ones normally used at present, since the system reaches the desired thermal uniformity in a faster way.
Once the energy source stops generating energy for the heat exchange, the cross circulation of the fluid goes on due to thermal convection, ensuring a better thermal uniformity within the annular chamber for a long time.
In the following, further aspects of the invention are described. Such further aspects may be present in combination with the aspect of the invention previously and/or subsequently described or form a separate invention.
In a further embodiment, it is object of the present invention a device adapted to accumulate the thermally treated fluid, comprising: at least an accumulator of said thermally treated fluid, having an annular chamber with a substantially horizontal axis; a central core with a substantially horizontal axis, adapted to determine said annular characteristics of the chamber, adapted also to determine a circulation of the fluid in a cross direction in said annular chamber.
Preferably said device further comprises at least one heat exchange element, completely arranged on one side of the chamber with respect to the vertical plane of symmetry of the chamber itself.
According to an aspect of the invention, a device adapted to accumulate the thermally treated fluid is provided, comprising:

- at least one accumulator of said thermally treated fluid, having an annular chamber and a substantially horizontal axis;
- a central core having a substantially horizontal axis, adapted to determine said annular characteristics of the chamber, adapted also to determine a circulation of the fluid in a cross direction in said annular chamber.

Preferably the device further comprises at least one heat exchange element arranged in the annular chamber, on only one side of the chamber with respect to the vertical plane of symmetry of the chamber.
Preferably in the device said at least one annular chamber accumulator comprises more coaxial, or arranged one inside the others, annular chambers.
Preferably, said central core in the device comprises a solid internal volume, preferably made of insulating material, or at least partially hollow.
Preferably the device comprises a medial separator in said internal volume, said medial separator leaving an upper and a lower part free in the central core, in order to determine a circulation of the fluid in a cross direction in said internal volume.
Preferably the device comprises internal dividing walls between said coaxial or internally arranged one inside the other annular chambers, each one of said internal dividing walls being insulated or not.
Preferably in the device said at least one accumulator is shaped as an annular cylindrical chamber, or ovoid, or polygonal, or oval, namely parallelepiped with or without chamfered angles.
Preferably in the device said at least one heat exchange element comprises more parallel longitudinal heat exchangers, with equal or different diameters, in fixed or extractable version.
Preferably in the device said at least one heat exchange element comprises one or more linear or non-linear heat exchangers, or coils, or corrugated or finned heat exchangers, or at least a partially hollow space.
According to another aspect of the invention, a method for the accumulation of the thermally treated fluid is provided, characterized in that it provides the steps of:

- providing a device according to any one of the preceding features;
- introducing a fluid to be treated thermally in said device, in order to obtain a cross rotatory motion of said fluid within the device.

In these alternative embodiments (FIGS. 14-29) the device according to the invention comprises (FIG. 14) at least one annular chamber accumulator 201 having a substantial horizontal axis; the axis being either concentric or eccentric.
The annular chamber is externally delimited by an external wall 202, and internally delimited by an internal wall 203, which delimits the central core 204. As a rule, the external wall is insulated, while the internal wall (point 203 of FIGS. 14, 15 and 25, point 208 of FIG. 26) may or may not be insulated.
The annular chambers are closed at the opposite ends by means of end walls not shown in the figures, in a way per se known.
Furthermore, at least one heat exchange element 205 is present in the annular chamber, completely arranged on one side of the chamber with respect to the vertical plane of symmetry (polar medial plane) 206 of the chamber itself, and preferably arranged parallel to the horizontal axis. The length and the width of each one of the thermal exchange elements 205 of the FIGS. from 14 to 27 is a function of the volume of the treated fluid and of the temperature that one must obtain.
By arranging the heat exchange element 205 (FIG. 14) or elements (FIG. 15, 21, 22, 23) on only one side of the annular chamber, a cross rotatory movement of the fluid within the annular chamber is generated (see arrows 207), accelerating the process of mixing the fluid and obtaining a substantial temperature uniformity of the fluid itself within the chamber, both during the heat exchange and at the end of it. This effect is obtained for the heat exchange both reducing and increasing the temperature. As regards, the direction of rotation of the fluid, the latter can be clockwise or counter-clockwise, depending on the side wherein the heat exchange elements are present and on whether the exchange decreases or increases the temperature, taking into account that the natural circulation of the fluid moves upwards when the temperature is increasing and downwards when the temperature is decreasing. The variation of the temperature value of an accumulation thus obtained is very slow, by virtue of the fact that the temperatures are substantially uniform in the whole annular volume.
The configuration of the said annular chambers, and thus of both their internal and external walls can be indifferently cylindrical (FIG. 16), ovoid (FIG. 17), polygonal (FIG. 18), or oval (FIG. 19) namely parallelepiped (FIG. 20) with or without chamfered angles, or of further shapes.
More coaxial annular chambers (FIG. 15) may be present or they may anyway be arranged one inside the other: the number of annular channels depends on the volume of treated fluid, or on the heat exchange to be carried out.
The simplest technical configuration is represented by the cylindrical configuration with coaxial or not annular chambers.
FIG. 25 shows an alternative embodiment wherein the central core 204 conditions the kinetics of the treated fluid without having any accumulation function. The central core, for example, is a hollow space or it is filled with insulating material.
FIG. 29 shows an alternative embodiment wherein the thermal configuration is eccentric: more in particular, the external annular chamber 212 is eccentrically displaced upwards with respect to the internal annular chamber 213 and to the central core 204. Such configuration is particularly advantageous in case of heat exchange decreasing the temperature. In case, on the contrary of heat exchange increasing the temperature, an eccentric configuration wherein the eccentricity is turned in the opposite direction is particularly advantageous, namely the external annular chamber 12 is eccentrically displaced downwards with respect to the internal annular chamber 213 and to the central core 204.
The heat exchange system, regardless of its nature, is integrally displaced on the same side as the vertical plane of symmetry of the tank (FIGS. 21, 22, 23). Each annular chamber is preferably equipped with its own heat exchange system (FIG. 15).
As regards the heat exchange elements, the type of heat exchange can be of different nature (electric or thermal fluid or other), while the desired treatment speed is directly connected to the number of exchangers and to their specific power (the volume of the fluid to be treated being the same).
In the simplest plant configuration, the heat exchangers are configured as simple through pipes, for example fixed to the end walls of the annular chambers; their number depends on the speed and on the uniformity of functional heating of the productive cycle.
The exchangers may be of linear or non-linear shapes, coils, corrugated or finned fluid heat exchangers, supplied by a heat source selected according to the use or the needs, for example, electric, fluid thermal, also with a renewable energy source, for example solar, etc. . . . .
In case of a series of parallel longitudinal heat exchangers 205 (FIG. 24) they can have the same or different diameters: in the latter case it is preferable that the variation of the diameter decreases in upward direction, in case of a heat exchange increasing the temperature, and it decreases in downward direction in case of a heat exchange decreasing the temperature.
The heat exchangers can be positioned in a fixed or extractable version according to the production and/or maintenance needs.
FIG. 28 shows a further alternative embodiment of an heat exchange element made by at least a partial interspace (210) which realizes an extended exchange system on one side of the chamber 204, for example the internal side of the external wall 202.
As an alternative to the interspace space, a coil can be placed in order to realize an even larger exchange surface.
The realization of a system having one or more annular chambers results in a remarkable reduction of the time needed to make the mass of treated fluid reach the suitable temperature, both by heating and by cooling.
The number and the size of the annular chambers is directly connected to the volume of fluid to be treated. A high number of chambers allows also to carry out, in addition to the desired primary heat exchange, also the recovery of the thermal energy of the process, as a form of pre-heating or pre-cooling, using the same structure.
The central core 204 can be used as an accumulator of the thermally treated fluid and/or as a heat exchanger or as a single functional element that imposes the kinematic mechanism of the fluid.
The central core 204, can thus be a solid volume (FIG. 25), preferably full of insulating material, or a hollow volume, namely empty (FIG. 26), whose function is to contribute to generate the cross motion of the fluid. This solution is preferable when the overall volume of the device is small or when there are specific needs for the overall lightening of the system.
The wall dividing the central core 204 and the surrounding annular channel can be insulated (point 203, FIG. 14) or not insulated (point 208, FIG. 26).
An example of use of the alternative embodiment of FIG. 26 is in the food industry, for example for milk pasteurization. The milk to be warmed passes through a stainless steel pipe 204 after the water of the adjacent annular volume reached the suitable temperature. In this case, the dividing wall 208 is not insulated.
The central core 204 can also be a tank for accumulating thermal fluid at a predetermined temperature or it can be the only container from which the fluid, already conditioned and ready for the process is withdrawn.
In case a circulation is necessary also in the central core (see arrows 211 of FIG. 27), it can be obtained by interposing a separator 209 in medial position (FIG. 27), for example a simple plate welded at the end walls of the central core. The separator leaves an upper part and a lower part of the central core free, through which the circulation takes place.
The separator 209 can be positioned according to a zenith alignment or not, depending on whether it is necessary to insert one or more heat exchange elements.
The internal dividing walls between annular chambers can be insulated (wall 203, FIG. 14), in case it is necessary to maintain the thermal insulation between the fluids in the different chambers, or not insulated (wall 208, FIG. 26), if a further heat exchange function between the chambers is desired, for example in specific industrial processes, wherein it is necessary to make treatments at uniform temperature.
FIG. 26, indeed, shows an annular multi-chamber alternative embodiment, wherein the aim is to condition the fluid contained in the central core 204, in order to make rapidly uniform the treated fluid, while the external chamber acts as a flywheel for primary exchange thermal fluid.
The thermal vector or type of fluid selected to be inside the exchangers depends on the industrial process wherein the present invention is applied, as well as on its degree of viscosity. The material which the device is made of and/or is covered with is selected also depending on the chemical aggressiveness of the liquids treated and thus of their dangerousness.
There are no specific limits for the type of fluid to be treated: further constructive differentiations that will be realized will be directly connected to the type of technological process within which it will be used.
Experiments show very good results by making concentric tanks with ratio between internal and external diameter comprised between ½ and ⅓.
In the various embodiments described above the device that is object of the invention appears as a container closed by opposite walls, which can be inserted in any installation for the thermally treatment of the fluids. It must be equipped with appropriate valves and/or intake and withdrawal taps of the fluid from the annular chambers, and of connections of the heat exchangers to the respective energy sources. The person skilled in the art is able to make the installation and its connections by applying the normal technique known in the art.
It will be apparent to the person skilled in the art that other equivalent embodiments, and their combinations, of the invention can be conceived and reduced to practice without departing from the scope of the invention.
The thermal fluid does not have to be only water, but also other chemical substances, e.g. wine, milk, beer, fruit juices, and/or liquids from the chemical or petrochemical industry.
The effect of cross circulation of the fluid can exist also when the internal heat exchanger is not present. For example, in case of non-insulated external walls, it is possible to obtain an effect of internal heating, and consequently the effect of cross circulation of the fluid, by a thermal irradiation produced through the non-insulated walls, for example a solar irradiation or an irradiation of a different nature.
The advantages deriving from the application of the present invention in these alternative embodiments (FIGS. 14-29) are evident.
The device allows to obtain a fast and efficient thermal uniformity, both for heating and for cooling, with respect to the traditional accumulation boilers currently used in the different production cycles.
Extremely more efficient results can be obtained both in the heating step and in the settling step of the temperature of the process, by using, in fact, lower peak internal temperatures or anyway for a definitely shorter time than the traditional systems.
Both constant and variable annular sections can be used, depending on whether one wants to exploit the speed of the operating process to optimize the conditioned volume or the desired temperature variation.
The configuration of the annular chamber allows to remove the turbulences and the inertias that slow down the process of making the fluid to be treated reach the suitable temperature. The heating speed and the stratification of the fluid contained in the annular chamber will be connected to the number and to the section of the heat exchangers that will be placed inside the system.
The system allows to obtain a remarkable energy saving regardless of the vector fluid and of the liquid that one wants to condition, also due to the possibility of setting lower maximum temperatures than the ones normally used at present, since the system reaches the desired thermal uniformity in a faster way.
Once the energy source stops generating energy for the heat exchange, the cross circulation of the fluid continues, due to thermal convection, ensuring a better thermal uniformity within the annular chamber for a long time.
Further aspects of the invention deriving from the need of solving the problems described below will be described in the following. Such further aspects may be present in combination with the aspects of the invention previously and/or subsequently described or form a separate invention, relating more precisely to a boiler with burner with improved accumulation and internal circulation of thermally treated fluid.
A boiler with burner of the type known for the production of hot water or steam is realized according to a scheme which provides a tube bundle for the back-fire or fire-tubes.
The boiler has two large diameter pipes, one inside the other; the external shell contains, in addition to the pipe where the flames of the burner are conveyed, also the thermal fluid, as to produce hot water and/or steam.
The boiler has a burner axially aligned to the external shell.
Generally the burner is placed in the front part of the boiler and generates hot gases of the combustion that, after passing through the central furnace, they reverse their motion in a rear chamber called reversal chamber, outside the framework of the boiler, and are conveyed in tube bundle (second pass).
Once having reached the front part of the generator, the flue gases are reversed a second time and are then diverted in the third pass towards the external chimney in the rear part.
The tube bundles that are mounted around the shell of the burner are universally positioned on the upper part and in a symmetrical way in relation to the sides.
This allows to obtain an enormous exchange surface with respect to the water contained in the annular portion of the boiler.
This known configuration implies problems due to the remarkable thermal inertias in the annular portion of the boiler. The larger is the volume of water accumulation, the slower will be the process to reach the suitable temperature.
Furthermore, a considerable thermal stratification in vertical direction of the fluid within the annular portion is generated, thus the fluid tends to have a much higher temperature in the upper region compared to the one of the lower region. The high temperature gradient in vertical direction limits: the possibility of using the fluid; the volumes available at the highest temperature set in the system; furthermore recovering the desired temperature is harder, once it lowered due either to the process consumption or to the natural mixing because of the internal gradient.
Furthermore, a high internal turbulence develops during the step of thermal accumulation, which slows down the process of reaching the suitable temperature.
According to an aspect of the invention, a boiler with burner is provided comprising an annular chamber wherein a thermal fluid is present, characterized in that it comprises: one or more heat exchange elements arranged in the annular chamber, on only one side of the chamber with respect to the vertical plane of symmetry of the chamber, and adapted to determine a circulation of the thermal fluid in a cross direction in said annular chamber.
Preferably, in the boiler, said annular chamber develops in a substantially horizontal direction, and comprises an external wall and an internal wall.
Preferably in the boiler said annular chamber has a cylindrical, or ovoidal, or polygonal, or oval shape.
Preferably in the boiler said external and internal wall are concentric or eccentric.
Preferably in the boiler said one or more heat exchange elements comprise more parallel longitudinal heat exchangers, with equal or different diameters.
FIGS. 30-32 show a non limitative example of a boiler with burner according to an aspect of the invention.
In the FIG. 301 indicates the front plate of the boiler, 302 indicates the rear plate, 303 indicates the front plate, 304 indicates the furnace of the boiler, having a cylindrical shape with a substantially horizontal development, 305 indicates the flue in the rear region, 6 indicates the upper region of the boiler, 307 the tube bundle.
308 indicates the container of thermal fluid (typically water) which identifies a hollow space 318 with respect to the furnace of the boiler 304: the hollow space has an annular shape wherein the tubes of the tube bundle are present.
309 indicates a plate that supports the burner (not shown) applied from the outside of the front plate 303; 310 indicates the base region of the boiler; 311 the outlet (delivery) of the thermal fluid in the upper part of the container 308; 312 inspection hatches; 313 and 314 inlets of the thermal fluid.
315 indicates the containment chamber of the return flue gas placed at the back; in the chamber the exhaust flue 305 is arranged; 317 indicates the connection hinges of the front plate 303.
The burner generates hot combustion gases which, after passing through the furnace 304, collide with the rear plate 302 and reverse their motion in the furnace 304 itself. Once arrived in the front part of the boiler, the fumes are reversed a second time colliding with the front plate 303, and are conveyed in the tube bundle 307, to be then diverted towards the external exhaust flue 305 at the back.
The tube bundle 307 in the annular chamber 318 is completely arranged on one side of the chamber with respect to the vertical plane of symmetry (polar medial plane) of the chamber itself, and preferably arranged parallel to the horizontal axis. The size of the tubes 307 is a function of the fluid volume treated and of the temperature that it is necessary to reach. The tubes 307 act as heat exchange elements with respect to the thermal fluid in the annular chamber 318.
By arranging the tubes 307 on only one side of the annular chamber, a cross rotatory movement of the fluid within the annular chamber is generated (see arrows 207), accelerating the process of mixing the fluid and obtaining a substantial temperature uniformity of the fluid itself within the chamber, both during the heat exchange and at the end of it. As regards, the direction of rotation of the fluid, the latter can be clockwise or counter-clockwise, depending on the side wherein the heat exchange elements are present and taking into account that the natural circulation of the fluid moves upwards when the temperature is increasing and downwards when the temperature is decreasing. The variation of the temperature value of an accumulation thus obtained is very slow, by virtue of the fact that the temperatures are substantially uniform in the whole annular volume.
The configuration of the annular chamber, and thus of its walls both external and internal can be indifferently cylindrical, ovoid, polygonal, or oval, or having further different shapes. The walls can be concentric or eccentric. An example of eccentric configuration of the section of the annular chamber is shown in FIG. 303, wherein in a non-limitative example, the eccentricity is turned towards the side opposite to the one where the tube bundle is.
The simplest technical configuration is represented by the coaxial cylindrical configuration.
The heat exchange system, regardless of its nature, is entirely placed on the same side of the vertical plane of symmetry of the tank.
As regards the heat exchange elements, the desired speed of treatment is directly connected to the number of heat exchangers and to their size (the volume of the fluid to be treated being the same).
In the simplest plant configuration, the heat exchangers are configured as simple through pipes, for example fixed to the end walls of the annular chamber; their number depends on the speed and on the functional heating uniformity of the productive cycle.
In case of a series of parallel longitudinal heat exchangers 307, they can have the same or different diameters: in the latter case it is preferable that the variation of the diameter decreases in upward direction, since heat exchange increases the temperature.
The size of the annular chamber is directly connected to the volume of fluid to be treated.
It will be apparent to the person skilled in the art that other equivalent embodiments of the non-limitative example described above in reference to FIG. 30-32, can be conceived and reduced to practice, without departing from the scope of the invention.
For example, other configurations of the boiler with burner are possible, provided that an annular chamber for the circulation of the thermal fluid is present, within which heat exchange elements are present on only one side of the annular chamber with respect to the vertical plane of symmetry.
The advantages deriving from the application of the present invention in the embodiments described with reference to FIGS. 30-32 are evident.
The device allows to obtain a fast and efficient thermal uniformity, both for heating and for cooling, with respect to the traditional accumulation boilers now used in the different production cycles.
Extremely more efficient results can be obtained both in the heating step and in the settling step of the process temperature, by using, in fact, lower peak internal temperatures or anyway for a definitely shorter time than the traditional systems.
The configuration of the annular chamber allows to remove the turbulences and the inertias that slow down the process of making the fluid to be treated reach the desired temperature. The heating speed and the stratification of the fluid contained in the annular chamber will be connected to the number and to the section of the heat exchangers that will be placed inside the system.
The system allows to obtain a remarkable energy saving regardless of the vector fluid and of the liquid that one wants to condition, also due to the possibility of setting lower 25, maximum temperatures than the ones normally used at present, since the system reaches the desired thermal uniformity in a faster way.
Once the energy source stops generating energy for the heat exchange, the cross circulation of the fluid goes on due to thermal convection, ensuring a better thermal uniformity within the annular chamber for a long time.
It will be apparent to the person skilled in the art that other equivalent embodiments, and their combinations, of the invention can be conceived and reduced to practice without departing from the scope of the invention.
From the description set forth above the person skilled in the art is able to realize the object of the invention without introducing further constructive details.
In particular the accumulation devices and the heat exchangers in the different embodiments described above can be realized by the person skilled in the art.
The elements and the characteristics shown in the different preferred embodiments can be combined with each other without departing from the scope of the present patent.

Claims

1. A device adapted to accumulate a thermally treated fluid, comprising:

a containment chamber of said thermally treated fluid; and

at least one separator arranged with a substantially vertical development in the containment chamber, said at least one separator being adapted to divide said chamber in at least two parts, and to leave openings at the opposite upper and lower end of said chamber, through which openings the fluid can pass in order to determine a rotatory circulation of the fluid in the cross direction in said chamber.

2. The device as in claim 1, further comprising at least one heat exchange element arranged in the containment chamber, in one of said parts of the chamber.

3. The device as in claim 2, wherein at least one of said parts of the chamber is without heat exchange elements.

4. The device as in claim 1, wherein said containment chamber has a cylindrical configuration, or ovoid, or polygonal, or oval, or parallelepiped with or without chamfered angles, developed in a substantially horizontal or vertical direction.

5. The device as in claim 2, wherein said at least one heat exchange element comprises more parallel longitudinal heat exchangers, with equal or different diameters, in fixed or extractable version.

6. The device as in claim 2, wherein said at least one heat exchange element comprises one or more linear or non-linear heat exchangers, or coils, or corrugated or finned heat exchangers, or at least a partially hollow space.

7. The device as in claim 1, wherein said separator is a simple plate, or an element comprising an insulation, for a better thermal separation between the parts into which the internal chamber is divided.

8. The device as in claim 1, wherein said separator has an elongated configuration with a straight or curved cross section.

9. The device as in claim 2, wherein said chamber is a furnace, and said at least one heat exchange element is one or more series of heating elements.

10. A method for accumulating thermally treated fluid, the method comprising:

providing a device according to any one of the preceding claims; and

introducing a fluid to be treated thermally in said device, in order to obtain a cross rotatory motion of said fluid within said device.