Patent Grant
11906206
This application is a 371 of PCT/IB2019/059100 filed Oct. 24, 2019, which claims the benefit of Italian Patent Application No. 102018000009843 filed Oct. 26, 2018.
The present invention refers to a refrigeration apparatus.
In particular, the refrigeration apparatus according to the invention is advantageously used in the refrigeration apparatuses that use carbon dioxide as coolant.
As is known, a refrigeration apparatus for a coolant of the type mentioned above comprises a closed circuit in which the coolant flows and along which a compressor, a cooler to cool the coolant, an expansion valve and an evaporator are arranged.
It should be noted that reference is made to fluid cooler and not to condensers in case of carbon dioxide or other fluids having similar properties, since the coolant will always remain at the gaseous state throughout the entire thermodynamic process carried out within the refrigeration apparatus.
In order to increase the efficiency of a refrigeration apparatus that uses carbon dioxide as coolant, it is also known to use one or more secondary economizer branches for the coolant circulating within the closed circuit. It should be noted that, according to the known art, a secondary economizer branch is fluidically connected to a section of the main branch of the closed circuit comprised between the cooling device, or cooler, and the expansion valve on one side and to the main compressor on the other. Such secondary economizer branch comprises an expansion valve and a heat exchanger for exchanging heat with the main circuit, while the flow rate coming from the secondary economizer branch has a pressure intermediate between the maximum one and the minimum one, which circulates within the refrigeration device, i.e. between the pressure of the fluid at the cooling device and that at the evaporator.
In any case, also with the use of one or more secondary economizer branches, the refrigeration apparatuses that use carbon dioxide as a coolant are not convenient in terms of energy. In fact, their efficiency is still rather low.
Object of the present invention is thus to achieve a refrigeration apparatus that can use refrigeration gases, for example, of the carbon dioxide (CO2) type, while increasing its efficiency with respect to those of the known art.
A further object of the invention is to achieve a refrigeration apparatus of increased efficiency that is not structurally complex.
These and other objects are achieved by a refrigeration apparatus having a closed circuit in which a flow rate of coolant circulates, said closed circuit comprising at least one main branch provided with at least one main compressor, at least one cooling device to cool said coolant, expansion means to expand the coolant and at least one evaporator, said closed circuit further comprising at least one secondary economizer branch for at least one fraction of flow rate of said coolant, wherein the inlet section of said at least one first secondary economizer branch is arranged in a section of said closed circuit comprised between said cooling device and said expansion means and the outlet section of said at least one secondary economizer branch is arranged in proximity of the suction of said main compressor, said apparatus being characterized in that said main branch further comprises at least one reciprocating compressor arranged between said evaporator and said main compressor and provided with at least one cylinder, at least one rod and at least one piston, the latter being integrally constrained to said at least one rod and translatable inside said cylinder, and in that said at least one secondary economizer branch comprises at least one control device for controlling the actuation of said at least one rod and adapted to divert at least one portion of said fraction of coolant coming from said secondary economizer branch to drive the displacement of said at least one piston and compress the coolant coming from said evaporator and contained in said cylinder, and to reintroduce said at least one portion of fraction of coolant into said secondary economizer branch during the displacement of said at least one piston in the step of suctioning the coolant coming from said evaporator, for the outflow of said at least one portion of fraction of coolant through said outlet section of said at least one secondary economizer branch, wherein said outlet section of said at least one secondary economizer branch is arranged downstream of said reciprocating compressor.
Thus, in substance, a portion of the coolant coming from the economizer branch and provided with a greater pressure than that of the coolant at the evaporator is used to provide the thrusting force of the piston of the reciprocating compressor arranged along the main branch and to thus compress the coolant coming from the evaporator. In the suctioning step of the reciprocating compressor, the same portion of coolant coming from the secondary economizer branch and used in the preceding compression step of the reciprocating compressor, is returned to the main branch in a length thereof comprised between the main compressor and the reciprocating compressor. Thus, the portion of coolant coming from the secondary economizer branch never mixes with the coolant compressed inside the reciprocating compressor and coming from the evaporator, but is readdressed in direction of the outlet section of the secondary economizer branch after having exerted a thrusting force on the piston of the reciprocating compressor, in the suctioning step of the reciprocating compressor. At the outlet section of the secondary economizer branch, the portion of coolant mixes with the coolant coming out of the reciprocating compressor.
According to a first embodiment of the invention, the cylinder of the reciprocating compressor is provided with a first chamber comprising a first port for the inflow of the coolant coming from said evaporator and a second port for the outflow of the compressed coolant contained in said first chamber in order to reach said main compressor, wherein said cylinder further comprises a second chamber fluidically separated from said first chamber by said piston and provided with at least one third port for the inflow of said portion of said at least one fraction of coolant for displacing said piston and compressing said coolant contained in said first chamber, and for the outflow of said portion of said fraction of coolant, at the end of the compression of the coolant in said first chamber, in order to reach said outlet section of said secondary economizer branch, i.e. the suction of the main compressor.
Thus, as stated above, the portion of coolant coming from the secondary economizer branch never mixes with the coolant inflowing within the first chamber, but is compressed and then comes out of the reciprocating compressor in order to reach the main compressor. The same portion of coolant that is used to push the piston during the compression step comes out of the second chamber of the cylinder of the reciprocating compressor in order to reach the outlet section of the secondary economizer branch and mix with the coolant compressed by the reciprocating compressor before entering the main compressor. Moreover, the control device for controlling the actuation of said rod comprises at least one inflow section fluidically connected with said secondary economizer branch, at least one outflow section fluidically connected with said outlet section of said secondary economizer branch, and cut-off means switching between a first configuration, wherein the fluidic connection between said inflow section and said at least one third port is allowed, for the inflow of said portion of said fraction of coolant into said second chamber, and a second configuration, wherein the fluidic connection between said outflow section and said at least one third port is allowed, for the outflow of said portion of said fraction of coolant from said second chamber and the fluidic connection between said inflow section and said at least one third port is not allowed.
In particular, the actuation control device comprises a cylinder body. Moreover, the cut-off means comprise at least one shaft translatable within said cylinder between a first position, in said first configuration, and a second position, in said second configuration. The translatable shaft is provided with a first cut-off and a second cut-off; said first cut-off and said second cut-off being arranged spaced apart from one another along said at least one translatable shaft such that, in said first position, the fluidic connection between said inflow section and said at least one third port is allowed, for the inflow of said portion of said fraction of coolant into said second chamber, and in said second position the fluidic connection between said outflow section and said at least one third port is allowed, for the outflow of said portion of said fraction of coolant from said second chamber, and the fluidic connection between said inflow section and said at least one third port is not allowed.
According to an embodiment of the invention, said at least one reciprocating compressor comprises at least one additional piston integrally constrained to said at least one rod and translatable within said cylinder, wherein said cylinder is provided with an additional first chamber comprising an additional first port for the inflow of the coolant coming from said evaporator and an additional second port for the outflow of the compressed coolant contained in said additional first chamber to reach said main compressor. Moreover, said cylinder further comprises an additional second chamber fluidically separated from said additional first chamber by said additional piston and provided with an additional third port for the inflow of an additional portion of said fraction of coolant in order to displace said additional piston and compress said coolant contained in said additional first chamber and to allow the simultaneous suction of coolant from said evaporator into said first chamber, and for the outflow of said additional portion of said fraction of coolant following the compression of the coolant contained in said additional first chamber and the simultaneous compression of the coolant contained in said first chamber by said piston.
In practice, the reciprocating compressor is of the double-acting type, thus, when the piston is in the suction step, the additional piston is in the compression step, and vice-versa. Thus, this allows to considerably increase the flow rate of coolant that can be circulated inside the closed circuit.
According to a particular aspect of the invention, said control device for controlling the actuation of said rod further comprises at least one additional outflow section fluidically connected with a length of said main branch comprised between said main compressor and said reciprocating compressor. Said cut-off means, at least when in said first position, allow the fluidic connection between said additional outflow section and said additional third port, for the outflow of said additional portion of the fraction of coolant from said additional second chamber, and at least when in said second position, allow the fluidic connection between said inflow section and said additional third port, for the inflow of said additional portion of the fraction of the coolant into said additional second chamber.
Said cut-off means comprise at least one third cut-off constrained to said translatable shaft. Such third cut-off is spaced apart from said first cut-off and said second cut-off along said translatable shaft such that, at least when said at least one translatable shaft is in said first position, the fluidic connection between said additional outflow section and said additional third port is allowed, for the outflow of said additional portion of the fraction of coolant from said additional second chamber, and at least when in said second position, the fluidic connection between said inflow section and said additional third port is allowed, for the inflow of said additional portion of the fraction of the coolant into said additional second chamber.
According to a third embodiment of the invention, said cylinder is provided with a first chamber comprising a first port for the inflow of the coolant coming from said evaporator and a second port for the outflow of the compressed coolant contained in said first chamber in order to reach said main compressor, wherein said cylinder further comprises a second chamber fluidically separated from said first chamber by said piston and provided with at least one third port for the inflow of said portion of said fraction of coolant for displacing said piston and compressing said coolant contained in said first chamber, and at least one fourth port for the outflow of said portion of said fraction of coolant, at the end of the compression of the coolant contained in said first chamber, in order to reach said outlet section of said secondary economizer branch, i.e. the suction of said compressor.
Always according to this embodiment, said control device for controlling the actuation of said rod comprises at least one inflow section fluidically connected with said secondary economizer branch, at least one outflow section fluidically connected with said outlet section of said secondary economizer branch, and cut-off means switching between a first configuration, wherein the fluidic connection between said inflow section and said at least one third port is allowed, for the inflow of said portion of said fraction of coolant into said second chamber, and a second configuration, wherein the fluidic connection between said outflow section and said at least one fourth port is allowed, for the outflow of said portion of said fraction of coolant from said second chamber and the fluidic connection between said inflow section and said at least one third port is not allowed.
According to a fourth embodiment of the invention, which includes a part of the characteristics of the third embodiment, said inflow section and said outflow section are obtained in said cylinder of said reciprocating compressor. The cut-off means comprise at least one first small piston and at least one second small piston arranged within said cylinder and translatable within a respective cylinder housing obtained in said cylinder, between a respective first position, in order to take said first configuration, and a respective second position, in order to take said second configuration. Said first small piston is provided with a first cut-off and said second small piston is provided with a second cut-off, wherein said first cut-off is adapted to uncover said at least one third port at least when said first small piston is in said first position and to cover said at least one third port at least when said first small piston is in said second position. The second cut-off is adapted to cover said at least one fourth port at least when said second small piston is in said first position and to uncover said at least one fourth port at least when said second small piston is in said second position.
In a more efficient variant of this fourth embodiment, said at least one reciprocating compressor comprises at least one additional piston integrally constrained to said at least one rod and translatable within said cylinder, wherein said cylinder is provided with an additional first chamber comprising an additional first port for the inflow of the coolant coming from said evaporator and an additional second port for the outflow of the compressed coolant contained in said additional first chamber to reach said main compressor; said cylinder further comprising an additional second chamber fluidically separated from said additional first chamber by said additional piston and being provided with an additional third port for the inflow of an additional portion of said at least one fraction of coolant in order to displace said additional piston and compress said coolant contained in said additional first chamber and allow the simultaneous suction of coolant from said evaporator into said first chamber, and with an additional fourth port for the outflow of said additional portion of said fraction of coolant at the end of the compression of the coolant contained in said additional first chamber and the simultaneous compression of coolant contained in said first chamber by said piston.
According to the fourth embodiment of the invention, in a preferred embodiment, said control device for controlling the actuation of said rod further comprises at least one additional inflow section obtained in said cylinder, fluidically connected with said secondary economizer branch. The cut-off means, at least when in said first configuration, prevent the fluidic connection between said additional inflow section and said at least one additional third port and allow the fluidic connection between said outflow section and said at least one additional fourth port, for the outflow of said additional portion of said fraction of coolant from said additional second chamber, and at least when in said second configuration, allow the fluidic connection between said additional inflow section and said at least one additional third port, for the inflow of said additional portion of said fraction of coolant into said additional second chamber and wherein the fluidic connection between said outflow section and said at least one additional fourth port is not allowed.
Moreover, said at least one first small piston is provided with an additional first cut-off and said second small piston is provided with an additional second cut-off. Said additional first cut-off is adapted to cover said at least one additional third port at least when said first small piston is in said first position and to uncover said at least one additional third port at least when said first small piston is in said second position. Moreover, said second additional cut-off is adapted to uncover said at least one additional fourth port at least when said second small piston is in said first position and to cover said at least one additional fourth port at least when said second small piston is in said second position. According to the invention, said coolant comprises carbon dioxide, or other gas or gas mixture having similar chemical and/or physical properties.
The objects are also achieved by means of a method for operating a refrigeration apparatus according at least to claim 1, said method comprising the steps of:
Several particular embodiments of the present invention will now be described by way of example only and without limitations with reference to the accompanying figures, in which:
With particular reference to such figures, 1 generally denotes the generic refrigeration apparatus according to the invention.
As shown in an extremely simplified way in
If the coolant is not carbon dioxide or has characteristics similar to this gas, the main compressor 2 could also be of the type different from the reciprocating one, for example centrifugal or other type, without however departing from the protection scope of the present invention. Moreover, in this particular case, the expansion means 4 comprise an expansion valve of the thermostatic type, in other embodiments they can comprise a capillary line or other mechanism, still however without departing from the protection scope of the present invention.
The closed circuit C further comprises a secondary economizer branch 100 for a fraction of flow rate X1 of the coolant. The inlet section 100a of the first secondary economizer branch 100 is arranged in a length 101 of the closed circuit C comprised between the cooling device 3 and the expansion means 4 and the outlet section 100b of the secondary economizer branch 100 is arranged in proximity of the suction of the main compressor 2. It should be noted that the secondary economizer branch 100 comprises, in a known way, an additional expansion valve 105 and a heat exchanger 106 to exchange heat with the main branch. A coolant, which, after the expansion step, has a pressure intermediate between that of the coolant coming out of the cooling device 3 and that of the coolant coming out of the evaporator 5, flows along the economizer branch 100.
According to the invention, the main branch M further comprises a reciprocating compressor 6 arranged between the evaporator 5 and the main compressor 2 and is equipped with a cylinder 7, a rod 8 and a piston 9, the latter being integrally constrained to the rod 8 and translatable inside the cylinder 7. Moreover, the secondary economizer branch 100, downstream of the heat exchanger 106, comprises a control device 50 for controlling the actuation of the rod 8 and adapted to divert a portion X2 of the fraction X1 of coolant coming from the secondary economizer branch 100 to drive the displacement of the piston 9 and thus compress the coolant coming from the evaporator 5 and contained in the cylinder 7 of the reciprocating compressor 6, and to reintroduce the portion X2 of fraction of coolant into the secondary economizer branch 100 during the displacement of the piston 9 in the step of suctioning the coolant coming from the evaporator 5, for the outflow of the portion X2 of fraction of coolant through the outlet section 100b of the secondary economizer branch 100. The outlet section 100b of the secondary economizer branch 100 is thus arranged downstream of the reciprocating compressor 6.
Thus, in practice, the portion X2 of the fraction X1 of the coolant passing through the secondary economizer branch is used to push the piston 9 into the cylinder 7 of the reciprocating compressor 6 thanks to the fact that its pressure is always greater than that of the coolant at the outlet of the evaporator 5. The main compressor 2 thus receives a fluid having a pressure greater than that of the coolant coming from the evaporator 4, but without using external work, such as for example an electric motor, to supply the reciprocating compressor 6. Using a numerical example, the pressure of the coolant at the outlet of the evaporator 5 is of about 20 bars, that of the coolant at the suction of the main compressor 2 is of about 24 bars, while the pressure of the portion X2 of the fraction X1 of coolant flowing along the economizer branch 100 and which is exploited to displace the piston 9 is of about 45 bars.
According to a first embodiment of the apparatus 1 shown in
The initial step of compressing the coolant coming from the evaporator 5, at a pressure of about 20 bars, and contained in the first chamber 10 is shown in
In particular, the control device 50 for controlling the rod 8 comprises an inflow section 51 fluidically connected with the secondary economizer branch 100, on the side of the inlet section 100a, an outflow section 52 fluidically connected with the outlet section 100b of the secondary economizer branch 100, and cut-off means 30 switching from a first configuration C1, wherein the fluidic connection between the inflow section 51 and the third port 21 is allowed, for the inflow of the portion X2 of the fraction X1 of coolant into the second chamber 20 (see
It should be specified that the thermodynamic conditions of the coolant at the inflow section 51 are those obtained downstream of the additional expansion valve 105 and of the heat exchanger 106 which are present along the secondary economizer branch 100. Thus, when writing, as done above and as will also be done below, that the inflow section 51 is fluidically connected with the secondary economizer branch 100, on the side of the inlet section 100a, we just refer to the fact that the coolant entering through the inflow section 51 is in the thermodynamic conditions of the fluid that crossed the additional expansion valve 105 and the heat exchanger 106 which are present along the secondary branch.
In the embodiment described in
According to a variant of the embodiment described above and shown in
An axonometric sectional longitudinal view of the reciprocating compressor 6 according to a second embodiment of the invention is shown in
In particular, as shown in the aforesaid figures, the reciprocating compressor 6 comprises, in addition to the elements present in the first embodiment described above, an additional piston 9′ integrally constrained to the rod 8 and translatable within the cylinder 7. Such additional piston 9′ is in a position opposite that of the piston 9 along the rod 8. In such embodiment, the cylinder 7 of the reciprocating compressor 6 is provided with an additional first chamber 10′ comprising an additional first port 11′ for the inflow of the coolant coming from the evaporator 5 and with an additional second port 12′ for the outflow of the compressed coolant contained in the additional first chamber 10′, to reach the main compressor 1. In practice, such reciprocating compressor 6 is of the double-acting type. The cylinder 7 of the reciprocating compressor 6 further comprises an additional second chamber 20′ fluidically separated from the additional first chamber 10′ by the additional piston 9′ and provided with an additional third port 21′, for the inflow of an additional portion X2′ of the fraction X1 of coolant coming from the economizer branch 100, to displace the additional piston 9′ and to thus compress the coolant contained in the additional first chamber 10′ and further allow the simultaneous suction of the portion X2 of coolant from the evaporator 5 inside, this time, the first chamber 10. Such additional third port 21′ is also adapted to allow the outflow of the additional portion X2′ of the fraction X1 of coolant following the compression of the coolant contained in the additional first chamber 10′ and the simultaneous compression of the coolant contained in the first chamber 10 by means of the piston 9. It should be noted that the second chamber 20 and the additional second chamber 20′ are not fluidically connected to each other.
In such embodiment, the control device 50 for controlling the actuation of the rod 8 further comprises at least one further outflow section 52′ fluidically connected with the outlet section 100b of the secondary branch 100, thus with a length of the main branch M comprised between the main compressor 2 and the reciprocating compressor 6. Moreover, the cut-off means 30, at least when in the first position P1 (see
Thus, consequently to that which was said above, when the cut-off means 30 are in the first position P1, the fluidic connection between the inflow section 51 and the third port 21 is allowed, for the inflow of the portion X2 of the fraction X1 of coolant into the second chamber 20, to compress the coolant contained in the first chamber 10 and, simultaneously, the fluidic connection between the additional outflow section 52′ and the additional third port 21′ is allowed, for the outflow of the additional portion X2′ of the fraction of coolant X1 from the additional second chamber 20′ (see
In particular, in the embodiment described herein, the cut-off means 30 comprise a third cut-off 34 constrained to the translatable shaft 31. Such third cut-off 34 is spaced apart from the first cut-off 32 and from the second cut-off 33, along the shaft 31, so that, at least when the translatable shaft 31 is in its first position P1, the fluidic connection between the additional outflow section 52′ and the additional third port 21′ is allowed, for the outflow of the additional portion X2′ of the fraction of coolant X1 from the additional second chamber 20′, and when in its second position P2, the fluidic connection between the inflow section 51 and the additional third port 21′ is allowed, for the inflow of the additional portion X2′ of the fraction X1 of the coolant into the additional second chamber 20′.
In practice, in the first position P1 of the shaft 31, the first cut-off 32 covers the outflow section 52, while the third cut-off 34 uncovers the additional outflow section 52′. In the second position P2 of the shaft 31, the first cut-off 32 uncovers the outflow section 52, while the third cut-off 34 covers the additional outflow section 52′. Both in the first position P1 and in the second position P2, the second cut-off 33 always keeps the inflow section 51 uncovered, but takes a position such that to divert the portion X2 of the fraction X1 of coolant, or the additional portion X2′ of the fraction X1 of coolant, in direction of the third port 21 or of the additional third port 21′.
According to the particular embodiment described herein, the control device 50 for controlling the actuation of the rod 8 comprises drive means 80 to drive the switching of the cut-off means 30 between the first configuration C1 and the second configuration C2, and vice versa, depending on the position of the rod 8 within the cylinder 7.
In the embodiment described herein, such drive means 80 to drive the switching of the configuration of the cut-off means 30 act on the translatable shaft 31 by displacing it from the first position P1 to the second position P2. Such drive means 80 can also be used likewise in the embodiment described in
In particular, in the embodiment described in
The displacement of the translatable shaft 31 is then obtained thanks to the pressure exerted by the coolant onto the ends 31a and 31b of the translatable shaft 31. In this case, the coolant is in fact withdrawn from two distinct points of the closed circuit C in which there are distinct pressures such that, on command of the first switching button 81 and of the second switching button 82, the ends 31a, 31b of the translatable shaft 31 are thus subjected to different pressures specifically adapted to modify just the position of the translatable shaft 31 itself from its first position P1 to its second position P2, and vice-versa.
In specific, the cylinder body 55 of the control device for controlling the actuation 50 comprises a first terminal volume V1 fluidically connected with the length of the main branch M comprised between the main compressor 2 and the reciprocating compressor 6, and a second terminal volume V2 fluidically connected in a controlled and reciprocating way with the length of the main branch M comprised between the main compressor 2 and the reciprocating compressor 6, when the first switching button 81 is activated by the piston 9, in order to displace the translatable shaft 31 from its first position P1 to its second position P2, and with the secondary economizer branch 100, at least when the second switching button 82 is activated by the additional piston 9′, in order to displace the translatable shaft 31 from its second position P2 to its first position P1. It should be noted that in the length of the main branch M comprised between the main compressor 2 and the reciprocating compressor 6, the pressure of the coolant will always be lower than that of the coolant in the secondary economizer branch 100. Such fluidic connections thus allow to directly urge the translatable shaft 31 to displace itself from a first position P1 and a second position P2, and vice-versa, without using external mechanisms, but by only using simple fluidic connections of the drive device 50 at points of the closed circuit C in which the coolant is at different pressures. Moreover, the first volume V1 comprises an elastic element 88 to force the cut-off means 30, but in particular the translatable shaft 31 at its first end 31a, to remain in its second configuration C2. Such elastic element 88 is essential when the pressure in the first volume V1 and in the second volume V2 is identical since in this case, thanks to the elastic force exerted by the elastic element 88 on the first end 31a of the translatable shaft 31, the latter will be displaced from its first position P1 to its second position P2, while when the second volume V2 will be in fluidic connection with the economizer branch 100, then the force exerted by the coolant on the second end 31b of the translatable shaft 31 will involve the displacement of the translatable shaft itself 31 from its second position P2 to its first position P1, thus overcoming both the pressure acting in the first volume V1 and the force produced at the elastic element 88 on the first end 31a.
In the embodiment shown in
A third embodiment of the invention is depicted in
Thus, ultimately, unlike the embodiment shown in
Like in the first embodiment, the drive device 50 comprises cut-off means 30 comprising two valves 30a, 30b fluidically connected, respectively, to the economizer branch 100 on the side of the inlet section 100a, and to the outlet section 100b of the economizer branch 100 on one side, and to the third port 21 and the fourth port 22 on the other. Such valves 30a, 30b open and close in an appropriately synchronized way to alternately switch the configuration of the drive device 50 between the first configuration C1 and the second configuration C2, and vice-versa.
A refrigeration apparatus 1 in a fourth embodiment is shown in
The control device 50 for controlling the actuation of the rod 8 comprises an inflow section 51 fluidically connected with the secondary economizer branch 100, on the side of the inlet section 100a, and an outflow section 52 fluidically connected with the outlet section 100b of the secondary economizer branch 100. However, in this embodiment, the inflow section 51 and the outflow section 52 of the reciprocating compressor 6 are obtained in the cylinder 7 of the reciprocating compressor 6 itself, such that the third port 21 and the fourth port 22 are arranged within the second chamber 20 of the cylinder 7 of the reciprocating compressor 6, as is anyhow clear in the description below. The cut-off means 30 comprise a first small piston 36 and a second small piston 37 which are arranged in the cylinder 7 within appropriate and respective cylindrical housings 36a, 37a within which they slide and can be translated from a respective first position P1 and P1′ to take the first configuration C1 (
The reciprocating compressor 6 further comprises an additional piston 9′ integrally constrained to the rod 8 and translatable within the cylinder 7. The cylinder 7 is provided with an additional first chamber 10′ comprising an additional first port 11′ for the inflow of the coolant coming from the evaporator 5 and an additional second port 12′ for the outflow of the compressed coolant contained in the additional first chamber 10′ to reach the main compressor 1. The cylinder 7 further comprises an additional second chamber 20′ fluidically separated from the additional first chamber 10′ by the additional piston 9′ and provided with an additional third port 21′ for the inflow of an additional portion X2′ of the fraction X1 of coolant, to displace the additional piston 9′ and compress the coolant contained in the additional first chamber 10′ and allow the simultaneous suction of the coolant from the evaporator 5 inside the first chamber 10. Moreover, the cylinder 7 is provided with an additional fourth port 22′ for the outflow of the additional portion X2′ of the fraction of coolant X1 at the end of the compression of the coolant contained in the additional first chamber 10′ and the simultaneous compression of the portion X2 of the fraction X1 of coolant coming from the evaporator 5 and contained in the first chamber 10 by means of the piston 9.
According to an embodiment described herein, the control device 50 for controlling the actuation of the rod 8 further comprises an additional inflow section 51′ obtained in the cylinder 7 of the reciprocating compressor 6, besides the inflow section 51, fluidically connected with the side of the secondary economizer branch 100 comprising the inlet section 100a. The cut-off means 30, at least when in the first configuration C1, do not allow the fluidic connection between the additional inflow section 51′ and the additional third port 21′ and allow the fluidic connection between the outflow section 52 and the additional fourth port 22′, for the outflow of the additional portion X2′ of the fraction of coolant from the additional second chamber 20′ (
Moreover, the first small piston 36 is provided with an additional first cut-off 38′ and the second small piston 37 is equipped with an additional second cut-off 39′. The additional first cut-off 38′ is adapted to cover the additional third port 21′ when the first small piston 36 is in its first position P1 and to uncover the additional third port 21′ when the first small piston 36 is in its second position P2. The additional second cut-off 39′ is adapted to uncover the additional fourth port 22′ when the second small piston 37 is in its first position P1′ and to cover the additional fourth port 22′ when the second small piston 37 is in its second position P2′. According to a particular aspect of the invention, the first small piston 36 is provided with a first protruding end 36b and a second protruding end 36c both dimensioned such that the first small piston 36 can be displaced from the first position P1 to the second position P2, and vice-versa, respectively under the action of the piston 9 and of the additional piston 9′, at least at the end of the respective step of suctioning the coolant coming from the evaporator 5 in the first chamber 10 and in the additional first chamber 10′.
Moreover, the second cut-off 39 and the additional second cut-off 39′ of the second small piston 37 are shaped such that the second small piston 37 can be displaced from the first position P1′ to the second position P2′, and vice-versa, under the action of the additional piston 9′ and of the piston 9, at least at the end of the respective step of suctioning the coolant coming from the evaporator 5 in the additional first chamber 10′ and in the first chamber 10.
The presence of the first protruding end 36b, the second protruding end 36c and the particular shape of the second cut-off 39 and of the additional second cut-off 39′ allows to displace the first small piston 36 and the second small piston 37 from their first positions P1, P1′ to their second positions P2, P2′, and vice-versa, without the intervention of external mechanisms or consumption of electric power, but simply by exploiting the stroke of the piston 9 or of the additional piston 9′.
The embodiments described above all share the same operating method, which comprises the steps of:
| Number | Date | Country | Kind |
|---|---|---|---|
| 102018000009843 | Oct 2018 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2019/059100 | 10/24/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/084545 | 4/30/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20100162740 | Ascani | Jul 2010 | A1 |
| 20180258922 | Ascani | Sep 2018 | A1 |
| 20190353414 | Karbiner | Nov 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 0239680 | Oct 1987 | EP |
| 2005016897 | Jan 2005 | JP |
| 2008142714 | Nov 2008 | WO |
| 2018137783 | Aug 2018 | WO |
| Entry |
|---|
| International Search Report and Written Opinion for Corresponding International Application No. PCT/IB2019/059100 (10 Pages) (dated Jan. 20, 2020). |
| Number | Date | Country | |
|---|---|---|---|
| 20210396431 A1 | Dec 2021 | US |
