Abstract
A method for processing at least one article in a pressing arrangement is provided. The method comprises the steps of: increasing the temperature in the load compartment by the at least one heating element in the furnace chamber; maintaining the increased temperature at a predetermined temperature level, T.sub.1, for a selected period of time, t.sub.1; and during the steps of increasing the temperature and maintaining the increased temperature, circulating the pressure medium within the pressure vessel by the at least one flow generator.
Claims
1. A method for processing at least one article in a pressing arrangement, the pressing arrangement including a pressure vessel including a pressure cylinder, a furnace chamber arranged within the pressure vessel for heating a pressure medium, wherein the furnace chamber includes at least one heating element, and a load compartment for holding the at least one article, wherein the load compartment is arranged inside the furnace chamber, and at least one flow generator for circulating pressure medium within the pressure vessel, wherein the method comprises: increasing a temperature in the load compartment by controlling the at least one heating element in the furnace chamber; maintaining the increased temperature at a predetermined temperature level for a first selected period of time; and during the increasing the temperature and the maintaining the increased temperature, circulating the pressure medium within the pressure vessel by controlling the at least one flow generator, wherein the method further includes during the increasing the temperature, circulating the pressure medium within the pressure vessel by controlling the at least one flow generator to operate at a first rate of revolutions per minute, and during the maintaining the increased temperature, circulating the pressure medium within the pressure vessel by controlling the at least one flow generator to operate at a second rate of revolutions per minute being lower than the first rate of revolutions per minute while maintaining forced convection within the pressure vessel.
2. The method according to claim 1, further comprising: during the increasing the temperature, increasing the temperature with a rate of at least 10° C./min.
3. The method according to claim 1, further comprising: during the increasing the temperature, maintaining a temperature difference in the load compartment within a temperature interval of 50° C.
4. The method according to claim 1, further comprising: during the maintaining the increased temperature, maintaining a temperature difference in the load compartment within a temperature interval of 8° C.
5. The method according to claim 1, further comprising: increasing a pressure in the load compartment; and maintaining the increased pressure at a predetermined pressure level for a second selected period of time.
6. The method according to claim 1, further comprising: after the increasing the temperature and the maintaining the increased temperature, decreasing the temperature in the load compartment.
7. The method according to claim 1, wherein the pressing arrangement includes at least one element for cooling the pressure medium, and the method further includes cooling the pressure medium by allowing pressure medium to pass through the at least one element.
8. The method according to claim 7, wherein the pressure vessel of the pressing arrangement further includes a top end closure, a bottom end closure, and at least one heat exchanging element arranged in at least one of the top end closure and the bottom end closure, and the method further includes circulating the pressure medium within the pressure vessel, whereby the pressure medium is arranged to pass through the load compartment, guiding the pressure medium through a passage of the at least one heat exchanging element for allowing a flow of pressure medium through the at least one heat exchanging element, and circulating a cooling medium within the at least one heat exchanging element for a cooling of the pressure medium arranged to flow through the at least one heat exchanging element.
9. The method according to claim 7, wherein the pressure vessel of the pressing arrangement further includes a heat absorbing element arranged within the pressure vessel and configured to absorb heat from the pressure medium, and the method further includes circulating pressure medium within the pressure vessel, whereby the pressure medium is arranged to pass through the heat absorbing element.
10. The method according to claim 1, wherein the furnace chamber is at least partly enclosed by a heat-insulated casing comprising a heat-insulating portion and a housing at least partly enclosing the heat-insulating portion, the pressing arrangement further includes a first flow generator arranged within the heat-insulated casing, and a second flow generator arranged beneath the heat-insulated casing, and the method further includes controlling a supply of pressure medium to at least one of the first flow generator and the second flow generator.
11. A method for high-pressure treatment of at least one article in a pressing arrangement, the pressing arrangement including a pressure vessel comprising a pressure cylinder, a furnace chamber arranged within the pressure vessel for heating a pressure medium, wherein the furnace chamber includes at least one heating element, and a load compartment for holding the at least one article, wherein the load compartment is arranged inside the furnace chamber, and at least one flow generator for circulating pressure medium within the pressure vessel, wherein the method comprises: arranging at least one article to be processed inside the load compartment; increasing a temperature in the load compartment by controlling the at least one heating element in the furnace chamber, and increasing a pressure in the load compartment; maintaining the increased temperature at a predetermined temperature level for a first selected period of time; maintaining the increased pressure at a predetermined pressure level for a second selected period of time; reducing the temperature in the load compartment; and during the increasing the temperature and maintaining the increased temperature, circulating the pressure medium within the pressure vessel by controlling the at least one flow generator, wherein the method further includes during the increasing the temperature, circulating the pressure medium within the pressure vessel by controlling the at least one flow generator to operate at a first rate of revolutions per minute, and during the maintaining the increased temperature, circulating the pressure medium within the pressure vessel by controlling the at least one flow generator to operate at a second rate of revolutions per minute being lower than the first rate of revolutions per minute while maintaining forced convection within the pressure vessel.
12. The method according to claim 11, wherein the furnace chamber is at least partly enclosed by a heat-insulated casing comprising a heat-insulating portion and a housing at least partly enclosing the heat-insulating portion, the pressing arrangement further includes a first flow generator arranged within the heat-insulated casing, and a second flow generator arranged beneath the heat-insulated casing, and the method further includes controlling a supply of pressure medium to at least one of the first flow generator and the second flow generator.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Exemplifying embodiments of the present invention will be described below with reference to the accompanying drawings.
(2) FIG. 1 is a schematic, in part sectional, side view of a pressing arrangement.
(3) FIGS. 2a-b are schematic, in part sectional, side views of a bottom portion of a pressing arrangement.
(4) FIG. 3 is a schematic, in part sectional, side view of a pressing arrangement.
(5) FIGS. 4-7 are schematic illustrations of methods according to embodiments of the present invention.
(6) All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate embodiments of the present invention, wherein other parts may be omitted or merely suggested.
DETAILED DESCRIPTION
(7) The present invention will now be described hereinafter with reference to the accompanying drawings, in which exemplifying embodiments of the present invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments of the present invention set forth herein; rather, these embodiments are provided by way of example so that this disclosure will convey the scope of the present invention to those skilled in the art.
(8) FIG. 1 is a schematic, in part sectional, side view of a pressing arrangement 100. The pressing arrangement 100 is intended to be used for pressing of at least one article, schematically indicated at reference numeral 5. The pressing arrangement 100 comprises a pressure vessel 2. Although not shown in FIG. 1, the pressure vessel 2 may comprise elements, means, modules, etc., such as one or more ports, inlets, outlets, valves, etc., for supplying and discharging pressure medium to and from the pressure vessel 2.
(9) The pressure vessel 2 comprises a pressure cylinder 1, a top end closure 3 and a bottom end closure 9. The pressure vessel 2 comprises a furnace chamber 18. The furnace chamber 18 comprises a furnace, or heater or heating elements, for heating of the pressure medium in the pressure vessel for example during a pressing phase of a treatment cycle. The furnace is schematically indicated in FIG. 1 by the reference numeral 36. In accordance with the embodiment of the present invention illustrated in FIG. 1, the furnace 36 may be arranged at a lower portion of the furnace chamber 18. In alternative or in addition, the furnace 36 could be arranged in proximity to the inner side, or lateral, surfaces of the furnace chamber 18. It is to be understood that different configurations and arrangements of the furnace 36 in relation to, e.g., within, the furnace chamber 18 are possible. Any implementation of the furnace 36 with regard to an arrangement thereof in relation to, e.g., within, the furnace chamber 18 may be used in any one of the embodiments of the present invention described herein. In the context of the present application, the term “furnace” refers to the elements or means for providing heating, while the term “furnace chamber” refers to the area or region in which the furnace and possibly the load compartment and any article are located. As illustrated in FIG. 1, the furnace chamber 18 may not occupy the whole inner space of the pressure vessel 2, but may leave an intermediate space 10 of the interior of the pressure vessel 2 around the furnace chamber 18. The intermediate space 10 forms a pressure medium guiding passage 10. During operation of the pressing arrangement 100, the temperature in the intermediate space 10 may be lower than the temperature in the furnace chamber 18, but the intermediate space 10 and the furnace chamber 18 may be at equal, or substantially equal, pressure.
(10) The outer surface of the outer walls of the pressure vessel 2 may be provided with channels, conduits or tubes, etc. (not shown), which channels, conduits or tubes for example may be arranged so as to be in connection with the outer surface of the outer wall of the pressure vessel 2 and may be arranged to run parallel to an axial direction of the pressure vessel 2. A coolant for cooling of the walls of the pressure vessel 2 may be provided in the channels, conduits or tubes, whereby the walls of the pressure vessel 2 may be cooled in order to protect the walls from detrimental heat building up during operation of the pressure vessel 2. The coolant in the channels, conduits or tubes may for example comprise water, but another or other types of coolants are possible. An exemplifying flow of coolant in channels, conduits or tubes provided on the outer surface of the outer walls of the pressure vessel 2 is indicated in FIG. 1 by the arrows on the outside of the pressure vessel 2.
(11) Even though it is not explicitly indicated in any of the figures, the pressure vessel 2 may be arranged such that it can be opened and closed, such that any article 5 within the pressure vessel 2 may be inserted or removed. An arrangement of the pressure vessel 2 such that it can be opened and closed may be realized in a number of different manners, as known in the art. Although not explicitly indicated in FIG. 1, one or both of the top end closure 3 and the bottom end closure 9 may be arranged so that it can be opened and closed.
(12) The furnace chamber 18 is enclosed by a heat insulated casing 6, 7, 8, and is arranged so that pressure medium can enter and exit the furnace chamber 18. In accordance with the embodiment of the present invention illustrated in FIG. 1, the heat insulated casing 6, 7, 8 comprises a heat insulating portion 7, a housing 6 which is partly enclosing the heat insulating portion 7, and a bottom insulating portion 8. Although the heat insulated casing is collectively referred to by the reference numerals 6, 7, 8, not all of the elements of the heat insulated casing 6, 7, 8 may be arranged so as to be heat insulated or heat insulating. For example, the housing 6 may not be arranged so as to be heat insulated or heat insulating.
(13) A first guiding passage 13 is formed on the inside of the heat insulating portion 7, between the heat-insulated portion 7 and a wall of the load compartment 19, and is arranged to guide pressure medium downwards which has passed through the load compartment 19. A guiding passage 11 is formed between the heat insulating portion 7 and the housing 6. As illustrated in FIG. 1, the guiding passages 10, 11, 13 are arranged to form at least a part of a loop within the pressure vessel 2. The flow of pressure medium during a phase of a treatment cycle is illustrated by the arrows within the pressure vessel 2 shown in FIG. 1. A part of the loop comprises the pressure medium guiding passage 11 formed between portions of the housing 6 and the heat insulating portion 7, respectively. The pressure medium guiding passage 11 is arranged to guide the pressure medium after having exited the furnace chamber 18 towards the top end closure 3.
(14) The pressing arrangement in FIG. 1 further comprises a first flow generator 30 arranged within the heat-insulated casing 6, 7, 8. Here, the first flow generator 30 is exemplified as a fan or the like for circulation of pressure medium within the furnace chamber 18. The guiding passage 13 is in fluid communication with the first flow generator 30, such that pressure medium from the guiding passage 13 may re-enter the load compartment via the first flow generator 30. The pressing arrangement 100 further comprises a second flow generator 32 arranged beneath the heat-insulated casing 8. Analogously with the first flow generator 30, the second flow generator 32 is also exemplified as a fan or the like for circulation of pressure medium. The second flow generator 32 is in fluid communication with the first flow generator 30 such that pressure medium circulated by the second flow generator 32 is fed to the first flow generator 30 for further feeding into the load compartment 19 of the pressing arrangement 100.
(15) FIGS. 2a-b are schematic, in part sectional, side views of a bottom portion of a pressing arrangement 100, e.g. as described and disclosed in FIG. 1.
(16) FIG. 2a describes the flow of pressure medium during a cooling stage or phase of the treatment cycle of the pressing arrangement and FIG. 2b describes the flow of pressure medium during a heating stage or phase of the treatment cycle of the pressing arrangement. In FIGS. 2a-b, the pressing arrangement comprises a first flow generator 30 arranged within the heat-insulated casing. Here, the first flow generator 30 is exemplified as a fan or the like for circulation of pressure medium within the furnace chamber 18. In accordance with the embodiment of the present invention illustrated in FIG. 1, the fan 30 may for example be arranged at the above-mentioned opening in the bottom insulating portion. The first guiding passage 13 is in fluid communication with the first flow generator 30, such that pressure medium from the guiding passage 13 may re-enter the load compartment 19 via the first flow generator 30. The pressing arrangement 100 further comprises a second flow generator 32 arranged beneath the heat-insulated casing. Analogously with the first flow generator 30, the second flow generator 32 is also exemplified as a fan or the like for circulation of pressure medium. The second flow generator 32 is in fluid communication with the first flow generator 30 via a tube 31 such that pressure medium circulated by the second flow generator 32 is fed to the first flow generator 30 for further feeding into the load compartment of the pressing arrangement.
(17) In FIG. 2a, which describes the flow during a cooling stage or phase of the treatment cycle of the pressing arrangement, pressure medium that is guided in the second guiding passage 10 back towards the furnace chamber 18 may enter a space between the furnace chamber 18—or the bottom insulating portion—and the bottom end closure. It will be appreciated that pressure medium which has passed through the second guiding passage 10, in which the pressure medium may have been further cooled by being led in proximity to the inner surface of walls of the pressure cylinder, may have a relatively low temperature. Hence, pressure medium of relatively low temperature may be transported, via the second flow generator 32, towards the first flow generator 30 for further transportation into the load compartment. The pressing arrangement 100 may further comprise a control arrangement (not shown) configured to control a supply of pressure medium from the first guiding passage 13 to the first flow generator 30 and to control a supply of pressure medium from the second guiding passage 10 to the second flow generator 32. The control arrangement may be further configured to control the operation (e.g. revolutions per minute, rpm) of the first flow generator 30 and/or the second flow generator 32. For example, in case a relatively rapid cooling in the treatment cycle of the pressing arrangement is desired, the control arrangement may be configured to supply a relatively large portion of the relatively cold pressure medium from the guiding passage 10 towards the load compartment via the second flow generator 32, e.g. by (fully) opening one or more valves.
(18) In FIG. 2b, which describes the flow during a heating stage or phase of the treatment cycle of the pressing arrangement, the control arrangement may be configured to stop any supply of pressure medium to the second flow generator 32 by closing one or more valves such that no, or a minimum, of (relatively cold) pressure medium is transported through the tube 31 towards the first flow generator 30. In combination herewith, the control arrangement may optionally be configured to open one or more valves for a supply of pressure medium to the first flow generator 30 for a circulation of (relatively warm) pressure medium. Hence, only pressure medium from the guiding passage 13 may be drawn into the first flow generator 30 and further transported in the load compartment of the pressing arrangement.
(19) FIG. 3 is a schematic, in part sectional, side view of a pressing arrangement 100 according to an exemplifying embodiment. It will be appreciated that the pressing arrangement 100 as shown has many features and components in common with the pressing arrangement shown in FIG. 1, and it is hereby referred to FIG. 1 for reasons of simplicity. In FIG. 3, a heat exchanging element 170 is arranged in the top end closure 3 of the pressing arrangement 100. The heat exchanging element 170 comprises a circuit 180 for allowing a circulation of cooling medium within the circuit 180 of the heat exchanging element 170 for a cooling of pressure medium arranged to pass through the heat exchanging element 170 in the top end closure 3. The pressure medium may, from the opening of the housing 6, pass through a passage 200 of the heat exchanging element 170 arranged in the top end closure 3. More specifically, the pressure medium may enter the passage 200 via an inlet 205 of the passage 200 at a central portion of the heat exchanging element 170, and exit the passage 200 via an outlet 210 at a peripheral portion of the heat exchanging element 170. Thereafter, the pressure medium may enter into the second guiding passage 10. It will be appreciated that pressure medium entering the heat exchanging element 170 may come into a relatively close thermal contact with the heat exchanging element 170 being cooled by the cooling medium passing through the circuit 180 thereof. Hence, the pressure medium may be cooled efficiently and/or quickly by the heat exchanging element 170. The circuit 180 of the heat exchanging element 170 comprises an inlet tube 185 which is fluidically connected to the circuit 180 via channels 197 for a supply of cooling medium to the circuit 180. Analogously, the circuit 180 comprises an outlet tube 195 fluidically connected to the circuit 180 for a discharge of cooling medium from the circuit 180. During operation of the heat exchanging element 170, the cooling medium is hereby arranged to circulate within the circuit 180 of the heat exchanging element 170 for a heat transfer or cooling of the pressure medium passing the top end closure 3. As the temperature of the cooling medium is significantly lower than the temperature of the pressure medium, there is a transfer of cold from the cooling medium to the pressure medium, or analogously, a transfer of heat from the pressure medium to the cooling medium. It will be appreciated that the heat exchanging element 170 as described in FIG. 3 is schematic, and that other configurations are possible. For example, the heat exchanging element 170 may alternatively be arranged in the bottom end closure 9 with the same or a similar circuit 180 as in the top end closure 3.
(20) FIG. 4 is a schematic illustration of a method 101 according to an embodiment of the present invention for treatment of at least one article in a pressing arrangement 100, e.g. as exemplified in FIG. 1. First, the method 101 comprises the step of increasing 110 the temperature in the load compartment, in which one or more articles are arranged, by the at least one heating element in the furnace chamber. The method 101 may increase 110 the temperature during time t.sub.0, wherein t.sub.0 may be dependent on factors such as the material of the articles to be treated or processed, the size and/or configuration of the pressing arrangement, etc. The time to may, for example, be 5 hours, preferably 3 hours, and more preferably 1.5 hours.
(21) The method 101 may increase 110 the temperature arbitrarily, i.e. in a non-specified manner. However, and according to a preferred embodiment, the method 101 may increase 110 the temperature in the load compartment with a rate (gradient) ΔT.sub.i/Δt of at least 10° C./min, preferably at least 30° C./min. Furthermore, and also according to a preferred embodiment, the method 101 may, during the step of increasing 110 the temperature, maintain the temperature difference in the load compartment within a temperature interval ΔT.sub.0 of 50° C., preferably 35° C., and most preferred 20° C.
(22) After the step of the method 101 of increasing 110 the temperature in the load compartment of the pressing arrangement 100, the temperature level T.sub.1 within the load compartment may be 500-3000° C., preferably 1000-1400° C., and more preferably ca. 1200° C.
(23) After the step of increasing 110 the temperature in the pressing arrangement 100, the method 101 may further comprise the step of maintaining 120 the (increased) temperature at the above-mentioned, predetermined temperature level T.sub.1 for a selected period of time t.sub.1. The selected period of time t.sub.1 of maintaining T.sub.1 may be 0.1-6 hours, preferably 0.5-4 hours, and more preferably 1-2 hours. According to a preferred embodiment, the method 101 may, during the step of maintaining 120 the increased temperature in the load compartment, maintain the temperature difference in the load compartment within a temperature interval ΔT.sub.1 of 8° C., preferably 5° C., and most preferred 2° C.
(24) The method 101 may further comprise the step of decreasing 140 the temperature in the load compartment after the steps of increasing 110 the temperature and maintaining 120 the increased temperature in the pressing arrangement. The temperature in the load compartment may be decreased 140 during time t.sub.2. The rate (gradient) ΔT.sub.d/Δt of the temperature reduction (i.e. the cooling rate) may be at least 200° C./min, preferably at least 250° C./min, and more preferably at least 300° C./min.
(25) During the steps of the method 101 of increasing 110 the temperature and maintaining 120 the increased temperature in the load compartment 19 of the pressing arrangement, as schematically indicated in FIG. 4, the method 101 further comprises circulating 130 the pressure medium within the pressure vessel by the at least one flow generator in the pressing arrangement. Hence, the method 101 comprises operating one or more of the flow generators both during the heating phase, in which the method 101 increases 110 the temperature in the load compartment, as well as during the holding phase, in which the method 101 maintains 120 the increased temperature in the load compartment. It will be appreciated that the method 101 hereby leads to a relatively even or uniform temperature distribution in the load compartment, both during the sub-phase of increasing 110 the temperature (heating phase) as well as during the sub-phase of maintaining 120 the increased temperature (holding phase). In other words, the difference ΔT.sub.0 in temperature in the load compartment of the pressing arrangement during the step of increasing 110 the temperature and the difference ΔT.sub.1 in temperature in the load compartment of the pressing arrangement during the step of maintaining 120 the temperature, may be relatively small by the inventive method of the present invention.
(26) FIG. 4 shows a further embodiment of the method 101 of the present invention. Here, the pressure medium within the pressure vessel is circulated by operating the at least one flow generator at a first rate R.sub.1 during the step of increasing 110 the temperature within the load compartment. Furthermore, the pressure medium within the pressure vessel is circulated by operating the at least one flow generator at a second rate R.sub.2 during the step of maintaining 120 the temperature within the load compartment, wherein the second rate R.sub.2 is lower than the first rate R.sub.1, i.e. R.sub.2<R.sub.1. For example, the method 101 may operate one or more of the flow generators at rate R.sub.1 during to and at rate R.sub.2 during t.sub.1. Furthermore, the method 101 may keep the second rate R.sub.2 relatively low, e.g. at a minimum rate for maintaining the forced convention by the flow generator(s) in the pressure vessel. The method 101 may furthermore operate one or more of the flow generators at a rate as a function of the fluid properties of the pressure medium. Hence, during the step of increasing 110 the temperature and/or the step of maintaining 120 the increased temperature, the method may be configured to circulate the pressure medium within the pressure vessel by operating the flow generator(s) at (a) rate(s) which is dependent on the fluid properties of the pressure medium.
(27) FIG. 5 is a schematic illustration of a method 200 according to an embodiment of the present invention for treatment of at least one article in a pressing arrangement 100, e.g. as exemplified in FIG. 1. Furthermore, it will be appreciated that the steps of the method 200 includes one or more of the steps of the method 101 as previously described in the text and by FIG. 4, and it is hereby referred to the mentioned text and figure for an increased understanding. Initially, i.e. at the leftmost portion of the T,P diagram of FIG. 5, the heating (i.e. increase in temperature T) is performed under vacuum, whereby the pressure P slightly decreases from the atmospheric pressure level. Thereafter, and in combination with the previously described steps of increasing, maintaining and/or cooling the temperature in the load compartment of the pressure vessel during operation of one or more flow generators, the method 200 further comprises the step of increasing 210 the pressure in the load compartment. The method 200 further comprises the step of maintaining 220 the increased pressure at a predetermined pressure level, P.sub.1, for a selected period of time, t.sub.3. The predetermined pressure P.sub.1 may be 20-500 MPa, preferably 50-300 MPa, and more preferably 80-250 MPa. It will be appreciated that the step of maintaining 220 the pressure in the load compartment may be performed (but not necessarily) simultaneously with the previously described step of maintaining the temperature in the load compartment. In other words, the selected period of time t.sub.3 of maintaining P.sub.1 may correspond to the selected period of time t.sub.1 of maintaining T.sub.1 in the load compartment.
(28) FIG. 6 is a schematic illustration of a method 400 according to one or more embodiments of the present invention for treatment of at least one article. The pressing arrangement, e.g. as exemplified in FIG. 1, may further comprise at least one element for cooling the pressure medium. Hence, after the steps of increasing the temperature and maintaining the increased temperature, the method 400 may comprise the step of decreasing 410 the temperature in the load compartment by means of the element(s). For example, the element may constitute or comprise a heat exchanging element arranged in the top end closure of the pressing arrangement as described in FIG. 3. More specifically, the heat exchanging element may comprise a circuit for allowing a circulation of cooling medium within the circuit of the heat exchanging element for a cooling of pressure medium arranged to pass through the heat exchanging element in the top end closure. The element may alternatively, or in combination herewith, constitute or comprise a heat exchanging element arranged in the bottom end closure of the pressing arrangement. Alternatively, or in combination herewith, the element may furthermore constitute or comprise a heat absorbing element arranged within the pressure vessel and configured to absorb heat from the pressure medium. The method 400 may further comprise the step of circulating 420 a pressure medium within the pressure vessel, whereby the pressure medium is arranged to pass through the load compartment. In case the pressing arrangement comprises a heat exchanging element arranged in the top end closure of the pressing arrangement, the method 400 may further comprise the step of guiding 430 the pressure medium through a passage of the heat exchanging element for allowing a flow of pressure medium through the heat exchanging element, and circulating 440 a cooling medium within the heat exchanging element for a cooling of the pressure medium arranged to flow through the heat exchanging element. Alternatively, or in combination with the heat exchanging element, the pressing arrangement may comprise a heat absorbing element arranged within the pressure vessel. The method 400 may thereby further comprise circulating 450 pressure medium within the pressure vessel, whereby the pressure medium is arranged to pass through the heat absorbing element.
(29) The method 400 may further comprise the step of controlling 460 a supply of pressure medium to at least one of one or more flow generators during one or more of the steps 410, 420, 430, 440 and/or 450. The method 400 may furthermore comprise the step of controlling 470 the operation of at least one of the one or more flow generators during one or more of the steps 410, 420, 430, 440 and 450. According to the pressing arrangement 100 as exemplified in FIG. 1, pressure medium that is guided in the pressure medium guiding passage back towards the furnace chamber may enter a space between the furnace chamber—or the bottom insulating portion and the bottom end closure. It will be appreciated that pressure medium which has passed the heat exchanging element and passed through the second guiding passage, in which the pressure medium may have been further cooled by being led in proximity to the inner surface of walls of the pressure cylinder, may have a relatively low temperature. Hence, pressure medium of relatively low temperature may be transported, via the second flow generator, towards the first flow generator for further transportation into the load compartment. Hence, by the step of controlling 460 a supply of pressure medium to the first and/or second flow generators and/or the step of controlling the operation (e.g. revolutions per minute, rpm) of the first and/or second flow generators, an even more controlled and/or faster heating, holding, and/or cooling phase of the treatment cycle may be achieved by the method 400. For example, the method 400 may stop any supply of pressure medium to the second flow generator by closing one or more valves such that no, or a minimum, of (relatively cold) pressure medium is circulated. In combination herewith, the control arrangement may optionally be configured to open one or more valves for a supply of pressure medium to the first flow generator for a circulation of (relatively warm) pressure medium.
(30) FIG. 7 is a schematic illustration of a method 500 according to one or more embodiments of the present invention for treatment of at least one article. The method 500 may first comprise the step of arranging 510 at least one article to be processed inside the load compartment of a pressing arrangement. The method 500 may thereafter comprise the steps of increasing 520 the temperature in the load compartment and increasing 530 the pressure in the load compartment. It should be noted that the steps of increasing 520 the temperature and increasing the pressure 530 in the load compartment may be performed simultaneously. The method 500 further comprises the step of maintaining 540 the increased temperature at a predetermined temperature level T.sub.1 for a selected period of time t.sub.1 by performing at least one step of one or more of the previously described methods 100, 200, 400. The method 500 may further comprise the steps of maintaining 550 the increased pressure at a predetermined pressure level P.sub.1 for a selected period of time t.sub.3. The steps of maintaining 540 the increased temperature and maintaining 550 the increased pressure may be performed simultaneously, i.e. the selected period of time t.sub.3 of maintaining P.sub.1 may correspond to the selected period of time t.sub.1 of maintaining T.sub.1 in the load compartment. The method 500 may further comprise the step of reducing 560 the temperature in the load compartment by performing at least one step of one or more of the previously described methods 100, 200, 400. The method 500 may further comprise controlling 570 a supply of pressure medium and/or controlling 580 the operation of at least one of the first and second flow generators.
(31) In conclusion, a method for processing at least one article in a pressing arrangement is disclosed. The pressing arrangement comprises a pressure vessel comprising a pressure cylinder, and a furnace chamber arranged within the pressure vessel for heating a pressure medium. The furnace chamber comprises at least one heating element, and a load compartment for holding the at least one article, wherein the load compartment is arranged inside the furnace chamber. The pressing arrangement further comprises at least one flow generator for circulating pressure medium within the pressure vessel. The method comprises the step of increasing the temperature in the load compartment by the at least one heating element in the furnace chamber. The method further comprises the step of maintaining the increased temperature at a predetermined temperature level for a selected period of time. During the steps of increasing the temperature and maintaining the increased temperature, the method further comprises the step of circulating the pressure medium within the pressure vessel by the at least one flow generator.
(32) While the present invention has been illustrated in the appended drawings and the foregoing description, such illustration is to be considered illustrative or exemplifying and not restrictive; the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the appended claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.
