Patent Application
20110314850
The invention relates to a self-supporting, substantially cuboid vacuum container which is particularly thin-walled, and the use thereof, especially for adsorption devices.
A vacuum container is normally required to effect evaporation in sorption machines as, for example, water can be used as a refrigerant, and as a result low pressures are necessary. The well-known classic vacuum containers exhibit a primarily cylindrical main body, which is composed, among others, of a metal shell which possesses a thickness of at least 4 mm or 5 mm. Such vacuum containers are extremely heavy in comparison to other sorption machine components. The internal fixtures in these vacuum containers are often rectangular, such as in laminated heat exchangers used as adsorbers, condensers, or evaporators. For these reasons, the space occupied by the vacuum container can often not be used effectively. This is detrimental to the power density and material costs, but also for the thermal mass (see
Thus in the prior art there were continual efforts and attempts to overcome these disadvantages. For example, attempts were made to produce cylindrical containers with corrugated reinforcement, whose shell is made of a material which is normally not thicker than 3 mm. Furthermore, non-self-supporting containers have been described which are supported internally by fixtures such as heat exchanger elements. This principle is known to the average skilled person, for example, via vacuum packaging in the food industry, whereby a thin vacuum film is stabilized and supported by the product contained inside.
In the prior art, various sorption heat pumps are described in which an adsorber/desorber unit comprises a heat-conducting receptacle, which is in thermally conductive contact with a heat exchanger. These well-known receptacles perform two functions: on the one hand, heat transfer between heat exchanger and sorbent and, on the other hand, they produce a stable structure for the adsorber/desorber unit. It is reported that this stable structure makes it possible to use an especially thin wall for the common housing of sorption heat pumps, since this structural unit is not required to provide additional stability, serving only to seal the interior space containing the adsorber/desorber unit and the condenser/evaporator unit, against the outside environment. Typically, the exterior wall is designed as a thin sheet metal casing and has a thin wall thickness such that, especially after vacuum impinging, it rests against the adsorber/desorber unit or condenser/evaporator unit and is supported by them. As the thin sheet metal casing is braced and supported by the above-named units, such casings are referred to as non-self-supporting vacuum envelopes or as unsupported vacuum envelopes.
Numerous self-supporting containers are known to the specialist (JP 63280964 A; GB 2303694 A, DE 10 2007 003 077 A1; DE 10 2006 032 304 A1). These well-known, partially self-supporting vacuum containers have a circular cross section and are, as a rule, joined together by several circular shell segments. In particular, JP 63280964 A describes a cylindrical, self-supporting vacuum container. GB 2303694 discloses an ultra-light, laminated vacuum container made of a synthetic material.
Self-supporting thin-walled tanks are also used in the construction of hull structures for aircraft or tank structures for rockets, however, these tanks cannot be used as vacuum containers. The majority of well-known pressure containers, in as far as they are self-supporting, are cylindrical; vacuum containers are overwhelmingly cylindrical.
In addition to reinforcing cylindrical containers with corrugations it is also of course possible to produce rectangular vacuum containers with exterior walls exhibiting a wall thickness of at least 5 mm and which are additionally given support by internally located reinforcement brackets.
These prior art solutions are collectively disadvantageous, as even cylindrical containers, which in some cases may have only a 3 mm-thick, thick-walled casing, only allow for poor volume usage when fitted with rectangular internal fixtures.
The first very convincing, non-self-supporting vacuum containers exhibit many drawbacks in practical use, as vacuum forces are absorbed by the container walls and transferred to alt internal components and fixtures. All internal parts of the device must be finely positioned in relation to each other, resulting in numerous dependencies during construction. Furthermore, only very stable components can be used, components which are capable withstanding the mechanical loads transferred by vacuum forces. Heat transfer devices required for thermal decoupling of components, as well as spacers, regularly result in dead volume (see
Therefore, the object of the invention was to provide a device that does not exhibit the disadvantages of the prior art.
It was very surprising that for sorption machines, particularly adsorption chillers, a self-supporting vacuum container with container walls, i.e., with the exterior walls and in some cases partition walls inside the container, can be produced, which is cuboid or substantially cuboid with container walls exhibiting a thickness of under 3 mm, preferably less than 2 mm, and particularly preferably less than 1 mm. In the prior art there is no mention of self-supporting vacuum containers for sorption machines, in particular adsorption machines, which are cuboid and exhibit walls with the above-specified wall thicknesses. Developments in the state of the art were in an entirely different direction. Proposals have been advanced for either thin-walled, tubular, self-supporting vacuum containers, or thin-walled rectangular, non-self-supporting vacuum containers, whereby thin-walled is taken to be less than 3 mm.
For the average specialist there was no encouragement to furnish thin-walled vacuum containers—particularly not for adsorption chillers—which are cuboid and self-supporting and whose exterior walls exhibit a thickness of less than 3 mm, preferably less than 2 mm and particularly preferably less than 1 mm. In particular this means that thin-walled vacuum containers exhibit exterior walls or container walls with a wall thickness of less than 0.8 mm, preferably less than 0.7 mm and particularly preferably less than 0.6 mm. Self-supporting vacuum containers with such minimal wall thicknesses of the exterior walls are particularly advantageous in that they are very light while still being able to withstand the mechanical load of vacuum forces. It was very surprising that vacuum containers can be furnished with the above wall thickness according to the invention, and above all with the preferred wall thickness, which under vacuum forces (pressure or vacuum, depending on which pressure is used as a reference; a vacuum inside a container leads, for example, to increased pressure exerted against it) will indent selectively and yet remain completely functional. The selective indenting means that vacuum containers are implosion-resistant but become distinctly deformed under vacuum impinging. Previously, the average specialist has assumed that such vacuum containers cannot be used under any circumstances in sorption machines, particularly in adsorption machines. Previously, such vacuum containers have not been used in said manner since the expert community presupposed instability and uncertainty on the part of such containers. It is to the credit of the inventors to have demonstrated that even a clearly perceptible depression or indenting of the vacuum containers subjected to pressure impinging (and depending on the degree of deformation, even following the application of negative pressure in a resting phase), in the vacuum container according to the invention, in particular when used in an adsorption chiller, does not lead to functional failure or other disadvantages. The depression results from the application of negative pressure and can therefore be defined as a consequence of such.
It was very surprising that the problem of the invention can be solved by a thin-walled self-supporting cuboid vacuum container, exhibiting preferably exterior struts, sections or brackets, or interior or exterior corrugations. In the prior art there is no mention of self-supporting thin-walled cuboid vacuum containers for sorption heat pumps. The inventive containers are lighter and less expensive than those in the prior art and exhibit container walls with a thickness of <3 mm, ≦2 mm, ≦1 mm. Unstable fixtures can also be deployed inside these self-supporting rectangular vacuum containers as they are not required to absorb the vacuum forces. This furthermore obviates the technical necessity of placing fixtures directly up against each other, as well as the need for thermal decoupling of the components which otherwise would be pressed up against each other in sorption heat pumps. The inventive self-supporting cuboid vacuum containers for sorption machines contain at least one heat exchanger according to the invention. Preferably, the inventive container may exhibit either interior or exterior braces or corrugations in the wall of the self-supporting vacuum container.
It was completely surprising that, in particular, solid-sorption heat pumps comprising
Accordingly, a deformable, i.e., implosion-resistant vacuum container is furnished in particular for adsorption chillers.
Unlike the prior art, the collapsive forces generated by the vacuum are not diverted to the adsorber/desorber unit, condenser, evaporator and/or the condenser/evaporator unit or to the receptacle as the vacuum container according to the invention is a self-supporting vacuum container. Thus, for the purposes of the invention, adsorber chambers, the condenser or the evaporator, as well as other possible components are enclosed in a cantilevered vacuum envelope.
The skilled person is familiar with several ways to stabilize a self-supporting container. These can include, for example, cladding, reinforcement, mounting plates and sections with different joining techniques, whereby the sections are joined, for example by adhesive bonding, spot welding, laser welding or soldering and applied to the self-supporting container. The supporting function is provided solely by this structure. The rigidity of the container can be increased by stiffening means that are either attached to an exterior side of the container wall or to the interior side.
The inventive container which can be reinforced by the stiffening elements is cuboid or substantially cuboid. A substantially cuboid vacuum container can for example be a container that deviates from an idealized rectangular shape without the average specialist describing it as not a rectangular vacuum container anymore. That is, for purposes of the invention, a vacuum container would be substantially rectangular if it exhibits at least one rounded corner. Another form of a substantially rectangular vacuum container would, for example, be a container wherein two elongated exterior walls are only substantially spaced parallel to each other. The specialist would also describe such a container as being rectangular.
It was very surprising that the container walls, if they exhibit a wall thickness of less than 3 mm, enable the construction of a self-supporting vacuum container for sorption machines. Until now, the expert community has assumed that vacuum containers for sorption machines, and in particular for adsorption chillers, can only be either tubular or non-self-supporting vacuum containers, such that it was completely surprising that self-supporting vacuum containers can be furnished with a wall thickness of less than 3 mm, preferably less than 2 mm and particularly preferably less than 1 mm, without the vacuum generated by the collapsive forces of the vacuum container being diverted to the receptacle, the heat exchanger and/or the condenser/evaporator unit.
In particular, it was very surprising that sorption machines, preferably adsorption machines, can be furnished with a vacuum container which is visibly deformed under a vacuum. A visible deformation here is taken to be a deformation that the average specialist perceives as significant in the form of depressions or buckling. Deformation is not meant to mean a deformation appearing on the vacuum container's exterior wall and measured in the tenths of one millimeter, but rather an indenting of the vacuum container which is optically perceptible without additional assistance.
In a particularly preferred design of the invention, if at least one stiffening means is placed on at least one exterior side of the container wall, this surprisingly leads to a good reinforcement of the self-supporting vacuum container when it is used in particular in adsorption chillers. Especially particularly preferred is, if 2, 3, 4, 5 or in particular 6 containers walls are stabilized by application of stiffening means on the exterior wall of the container.
Another preferred design of the invention can be devised such that at least one reinforcing means is attached to at least one interior side of the container wall. The attachment of the stiffening means leads to a surprisingly good or surprisingly high stability of the container.
It may be preferential for stiffening means to be disposed to only one container wall. Such self-supporting vacuum containers for sorption machines are particularly lightweight and yet exhibit surprisingly good stability.
Another preferred design of the invention is devised such that at least one, preferably several, stiffening means are disposed to at least one interior and exterior wall, preferably to several interior and exterior walls. This combination surprisingly results in particularly well-designed vacuum containers which do not exhibit the disadvantages of the prior art.
In another preferred embodiment of the inventive self-supporting vacuum container, the container can also possess at least one or more partition walls. Depending on the specific pressure conditions, the partition walls can be exposed to different forces. It was surprising that the application of stiffening means to any or all partition walls leads to a clearly improved self-supporting vacuum container. Since, due to stiffening means, the partition wall bends less in response to variously acting pressure levels (depending on the process, different process pressures can arise in the chambers formed by the partition walls), the inventively preferred vacuum container can be especially effectively used for sorption machines, in particular adsorption chillers.
Stiffening means may be comprised, for example, of struts, rods, brackets, square tubes, sections and/or corrugations. The specialist is aware of other possible ways of applying stiffening means. Of course, it is also possible for welds to be effected such that a stiffening is made possible by the shape and orientation of the weld seams. In such instances it is advantageous, for example, to join together the long walls of the rectangular vacuum container from several sections which are welded. The stability of the welding seams or welds can be increased by targeted deformation of the sheets that form the container wall. It is possible, for example, that the sheets possess brackets or grooves at their opposing ends, which interlock and are welded, soldered or riveted in the areas named. Advantageously, the formation of possible brackets, grooves or channels leads to an improved stability of the vacuum container. In another preferred design, it can be devised such that the different joined sheets exhibit different material composition and/or different dimensions, e.g. different thicknesses. That is, the container walls can be assembled from various sheets with different characteristics, whereby characteristics are taken to mean different metallic compositions or a different dimensioning of the sheets or a different surface- or other type of chemical or physical treatment of the sheets and/or stiffening means. Advantageously, the above-named stiffening means lead to a self-supporting vacuum container that does not exhibit the disadvantages of the prior art.
Another preferred embodiment of the self-supporting vacuum container for sorption machines is devised such that the vacuum container, which, on its walls, preferably on the exterior side of the container walls, has stiffening means disposed to it to stabilize the container walls, is stabilized additionally by means of a transverse or several transverse struts which comprise part of the container. Furthermore, the vacuum containers can be additionally stabilized by transverse frames, which are formed from brackets, sections and/or rectangular tubes or other device elements. Of course, the inventive vacuum container can be fashioned without the aforementioned additional stiffening means. But with certain unusual dimensionings of the vacuum container, the additionally mentioned stiffening means can be advantageous.
Corrugations in the context of the invention are manually or machine-made trough-shaped depressions in the wall of the container which serve to increase rigidity. Advantageously, the purpose of the reinforcement can be combined with a special design. The corrugations can be pressed manually into the sheet with a bordering hammer on a creasing anvil or automatically with a grooving machine, with the help of two grooving rolls. There are grooving roles for different forms. The effectiveness of a corrugation depends substantially on the following factors: position of the corrugation, form, flow, radius and disposition of the different corrugations with respect to each other. When used to provide stability to thin-walled vacuum containers, corrugated sheets should also be tested to determine the stresses to which they are exposed. The following types of loads occur as a rule: torsion, thrust, and normal force. There is no especially preferred ideal corrugation, as the following principles must always be taken into account in their design: a) an imagined cut through a corrugated sheet should advantageously cut at least one corrugation, b) the more uneven a corrugation runs, the greater the stiffening effect, and c) sheets with rectangular area can advantageously be provided with circularly extending grooves, and vice versa.
Particularly preferred are the stiffeners attached on the exterior, as these, for example—especially if they are welded—they can be post-processed very well. For example, the weld seam can be adjusted to the appropriate requirements. The walls of the vacuum container according to the invention can be reinforced such that they do not indent whatsoever in response to the applied vacuum, e.g. by possessing numerous reinforcements. Of course, it may also be preferred that the walls indent partially and be supported by interior or exterior stiffening elements. It may further be preferred that the indentation of the walls not be supported. In the inventive cuboid vacuum container the reinforcements in the form of brackets or struts, or in the form of corrugations, may also be placed so that, by way of example, only several or a single wall(s) are/is supported by a transverse strut. The skilled person in the art can readily determine, by routine tests, the number of corrugations, struts, or brackets that are necessary to ensure that the deforming forces leading to the indentation of the walls do not lead to a collapse and thus the destruction of the container.
The stiffening means may advantageously be designed such that they are operatively connected with pipe connections and pipe ducts or form such. That is, the stiffening means may be connective elements, for example in adsorption chillers with respect to hydraulic interconnection. It may further be preferred that the stiffening elements possess at least one pressure reducing element. Furthermore, preferred embodiments of the invention are advantageous when the stiffening means possess at least one steam valve. That is, in a particularly preferred embodiment of the invention either pressure reducing elements and/or steam valves can be integrated into separate stiffening means where appropriate. In the context of adsorption chillers, the terms pressure reducing elements or steam valves are well known to the specialist and need not therefore be explained in more detail.
Because of the pressure difference between the external pressure (as a rule absolute ambient pressure: 1,013 mbar) and the internal pressure (for example, absolute: 10 mbar), vacuum containers are exposed to strong forces acting on the container walls in the direction of the container interior. Here, as described above, there must be a distinction between the deforming forces which, for purposes of the invention, lead to an acceptable deformation of the container walls, and the collapsive forces that lead to a destructive deformation, in particular to an implosion of the vacuum container. In particular, non-self-supporting containers subject to the influence of vacuum forces on the vacuum container walls are not stable and implode. Therefore, due to the deformations which occur, they are not functional within the meaning of the teaching pertaining to the invention. The self-supporting containers, according to the teaching relevant to the invention, are stable under the influence of vacuum forces. Depending on the design of the containers there is no deformation or a deformation which, in the context of the invention, results in no adverse influencing of their application. In particular, the inventive self-supporting vacuum containers with no interior fixtures—i.e., empty containers—are also vacuum-stable and do not implode. The design of the cuboid vacuum containers as implosion-resistant containers, preferably in an adsorption chilling machine, it is not a formulation of the inventive object, as the skilled person—after learning the inventive teaching—without achieving an inventive step—can determine the wall thickness within the bounds of the selected wall density range, as well as the stiffening means so that the deformation of the vacuum container is taken into account and the vacuum container does not implode. It was surprising that, differently than suggested by the prior art, sorption machines can be furnished according to the invention. In a preferred embodiment of the invention, the reinforcements of the inventive device serve to stabilize and fix a casing which envelops the sorption machine. It may also be advantageous if the reinforcements are designed so that the feet are integrated into them in the lower area. Advantageously, the stiffeners, such as struts, rods, sections, brackets, or corrugations, can also be designed so that the entire apparatus can be accessed from beneath by a lifting truck. With respect to this it can be particularly advantageous to construct these reinforcements so that they serve as attachment points for transport- and/or lifting devices. That is, in particularly preferred designs of the invention, the stiffening means may have additional functions. They can preferably be designed such that they constitute a fixing ring for the casing and/or they can be integrated into the feet of the entire device, i.e., the sorption machine. Therefore they can also function as attachment points for transporting or for lifting devices, or be employed in another functionality.
It was very surprising that the stiffeners can be designed so that all additional components associated with a sorption machine, e.g. controllers, display, or control boxes, can be affixed to these reinforcements.
The teaching of the invention enables the use of plates (less than 3 mm thickness) in the construction of vacuum containers, but also sheet metal as well. Sheet metal sheets are sheets with a thickness of less than 2 mm or preferably less than 1 mm. Preferably, warm or cold-rolled ready-made sheets are used; such sheets are chiefly used for forming purposes. Depending on the type of steel, these sheets can be surface coated with tin, zinc, copper, nickel, lacquer, enamel, or synthetic material.
The invention also relates to a sorption machine comprising at least one adsorber/desorber unit with heat exchanger and sorbent material, at least one condenser, at least one condenser/heat exchanger, at least one evaporator/condenser unit and/or an evaporator/heat exchanger, wherein at least one part of these building blocks is disposed in an inventive self-supporting vacuum container, and the sorption machine exhibits connection and coupling elements and pipe ducts for hydraulic interconnection and operation. Advantageously it is not necessary, for example, that the adsorber/desorber unit exhibit a stable structure, as it is not required to absorb or dissipate the collapsive forces generated by the vacuum. The average specialist knows, depending on the type of sorption machine involved, which of the above-named building blocks to use. The above-named listing represents a set of building blocks from which—depending on the type of sorption machine involved—individual units can be assembled; the specialist is aware of the selection and assembly of the individual components.
In a preferred embodiment of the sorption machine, the adsorber/desorber unit is located in an inner and/or partial inner housing, wherein the condenser/heat exchanger and the evaporator/heat exchanger are arranged at a distance from each other and the inner housing of the adsorber/desorber unit is provided in the space between them. The separating surfaces of the inner housing directed toward the condenser/heat exchanger and toward the evaporator/heat exchanger exhibit steam valves. It was a complete surprise that the inventive sorption machine, in particular the adsorption chiller via the cantilever-supported or self-supporting vacuum container, does not exhibit the above-mentioned disadvantages of the prior art.
Thus the invention also relates to the use of the inventive vacuum container for sorption machines, especially adsorption chillers. In a particularly preferred embodiment of the invention, provision is made that in the inventive vacuum container, building blocks are disposed such that the building blocks, by way of example, can be an adsorber/desorber unit, a condenser, an evaporator, a condenser/evaporator unit or an evaporation/condenser unit, an evaporator/heat exchanger and/or an evaporator/condenser unit.
The teaching according to the present application is characterized by the following features:
Departure from the technically customary
The existence of an old, unsolved urgent need for the solution of the problem which is solved by the invention
The simplicity of the solution speaks for the inventive step, in particular as it replaces complicated teachings
Misconceptions among experts about the solution of the respective problem (prejudice)
Technical progress, such as: improvement, increased performance, price reduction, savings in time, material, work steps, costs, and greater effectiveness, increase of technical possibilities, opening a second route, alternatives, possibility of rationalization,
In particular, the advantageous embodiments of the invention exhibit at least one or more of the named benefits.
In the following, and using the figures, the invention is explained in more detail while not being limited by them. The following is shown:
a) and b) Non-self-sustaining vacuum container
a) and b) Thin-walled vacuum containers according to the invention
a) and b) show non-self-supporting vacuum containers.
Furthermore, in
a) and b) show the inventive thin-walled vacuum containers. A condenser 1, an evaporator 2, and two adsorbers 3 are arranged in a thin-walled cuboid container 9a. In the case of adsorbers 3 it may be adsorber/desorber unit. The use of cuboid fixtures or components is preferred, as they require little space and can be arranged to save space. However, components with other forms such as round or oval can be used. Thin-walled refers to a wall thickness of less than 3 mm, preferably less than 2 mm and particularly preferably less than 1 mm. Metal can be used for the container 9a. Advantageously, stainless steel sheets or steel sheets, but other metals can be used. Stiffening elements 10 or reinforcing means are attached exteriorly to the container wall 9a. These may be struts, rods, brackets, corrugations, tubes and/or tubes which are made of materials such as metal, plastic, or ceramic materials. Welds can also be used as stiffening elements 10. The container walls 9a may be disposed such that a weld is used as a reinforcing element 10 and results in reinforcement of the container. Conceivable are container walls 9a assembled from several individual container parts and exhibiting lips or flanges at which the container parts are welded together. Welds can be used as a reinforcing element 10 in containers produced in this manner. The number of stiffening means 10 attached to the container wall 9a can be determined empirically by the specialist through known approaches. In some cases only a single container wall 9a need be provided with stiffening elements 10. The container 9a can be used with different sorption machines, such as adsorption or absorption machines and can be adapted easily and quickly to the size of the components to be encased.
The container wall 9a is self-supporting and is not supported by any elements, or connected to the fixtures. During operation of a sorption machine such as an adsorption chiller, a vacuum is applied to evaporate the refrigerant (e.g., water) at low temperatures in an evaporator 2. The resulting water vapor is conducted into the adsorber 3, where it adsorbs and releases thermal energy to a heat exchanger integrated into the adsorber 3. Here, a heat carrier flowing through the heat exchanger is heated up. In the next step, the adsorbed water vapor, due to energy from the adsorber 3, which now acts as a desorber, is expelled and condensed in a condenser 1, which transfers energy to the heat carrier located there. The application of a vacuum and the resulting vacuum forces causes no deformation of the container 9a, although the container may be constructed from a thin metal sheet.
In a preferred variant the vacuum forces are compensated by the container of the invention such that no deformation takes place. The stiffening elements 10 compensate for the vacuum forces and thus relieve the container wall 9a. In the prior art, mention is made of containers or vacuum containers for sorption machines, containers that are not self-supporting and/or are thick-walled, and in which on the one hand great demands are placed on the internal elements by vacuum forces, while on the other hand the machines are expensive and heavy. The inventive cuboid thin-wailed containers guarantee, however, that the fixtures are not subjected to loads and the container, and therefore the machine, is light in weight.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08075609.1 | Jul 2008 | EP | regional |
| 08075927.7 | Dec 2009 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE2009/000950 | 7/3/2009 | WO | 00 | 3/31/2011 |
