PRESSURE CONTROLLED MULTISTAGE COOLING PLANT AND CONTROL METHOD

Description

[0001] The present invention relates to the field concerning the plant for the cooling, warming and/or cooling air conditioning and relates to a pressure controlled multistage cooling plant with a pressure controlled method of a lower stage when it is in a non-active condition.

[0002] There are known cascade systems, i.e. plants in which the cooling system is slaved by another cooling system to allow its proper functioning, into which the so-called low-stage circuit can be used cooling fluids, such as carbon dioxide, that at the standard environmental temperatures of the temperate climate zones, have equivalent quite high pressures. This rise of the pressures, normally happens during plant shutdown periods between a cold cycle and the other, in function of various parameters such as the external temperature, the operative pressure before the stop, the thermal insulation, etc..

[0003] To counteract this phenomenon and to maintain the pressure within safety values a known solution, illustrated in Figure 2, provides the use of a small refrigerator system S which cools the cooling fluid contained in the storage tank when the pressure sensor "SP" will reach consensus value corresponding to a predetermined maximum pressure threshold. Obviously the cooling of the low stage cooling fluid, contained in the receiver, causes the desired reduction of the pressure.

[0004] This known solution has the drawback of high complexity, of a high cost and of a reduced efficiency.

[0005] There are also known solutions which provide a drawing of fluid in the liquid state from the high stage and the expansion of this fluid in an evaporator contained in the low stage receiver when the pressure sensor "SP" indicates the reaching of the threshold pressure.

[0006] One of the drawbacks of this configuration, for example, is that the high stage cooling plant is not installable in a single environment since it is necessary to bring a connection to the storage tank of the low stage cooling. Something that complicates the life when they are dealing with hazardous fluids such as hydrocarbons (e.g. propane also referred to as R290) is that said fluids are highly flammable.

[0007] One common disadvantage of said two known solution consists in that they require a receiver of the low stage internally provided with an exchanger, that is complicated and expensive also in consideration of all the connections that it requires.

[0008] One object of the present invention is to propose a multistage cooling plant with simple pressure control, reliable and inexpensive.

[0009] Further object is to propose a plant which allows using a low stage receiver simple, reliable, safe and cheap.

[0010] Another object is to have the entire high stage circuit in a unique environment by limiting to the latter all the provisions and tests on the safety against fire and explosion risks related to the particular cooling fluid usable in this stage.

[0011] Further object is to propose a highly efficient and secure system.

[0012] Other object is to propose a plant saving the main compressor of the high stage from wear and to save energy consumption.

[0013] Further object is to propose a method for the control and for the limitation of the pressure of the low stage fluid in inactivity conditions. The invention provides a cooling plant according to claim 1 and an operating method according to claim 10.

[0014] The document WO 2014/024837 discloses a multistage cooling plant with pressure control having at least a high stage comprising at least a set of first compressors, a set of first condensers, and a first duct of an intermediate heat exchanger means connected to form the high stage cooling circuit. This known plant is provided with at least a low stage comprising at least a set of second compressors, a second duct means of the intermediate heat exchanger means, a set of user apparatus connected to form the low stage cooling circuit. The plant comprises pressure sensor means assigned to detect the pressure of the low stage fluid and connected to control means assigned to activate feeding means when said pressure of the idle low stage fluid reaches or exceeds a predetermined threshold value. The feeding means in the activation condition are connected to a duct of the intermediate heat exchanger means in said duct a cooling fluid of refrigerator of the low stage fluid.

[0015] The characteristics of the invention are highlighted in the following with particular reference to the accompanying drawings in which:

• Figure 1 shows a schematic view of the multistage cooling plant with pressure control object of the present invention;
• Figure 2 shows a schematic view of a plant made on the basis of known prior art.

[0016] With reference to figure 1, numeral 1 indicates the multistage cooling plant with pressure control, object of the present invention, having a high stage 3, for example assigned to refrigerate, by means of its evaporators or heat exchangers, a set of medium temperature user equipment 13 or cells or rooms to be maintained at temperatures approximately between -5° C and + 5° C; obviously the high stage can carry out additional and/or alternative tasks, for example, the heating, cooling or air conditioning or, as better clarified in the following, the high stage 3 can be in the service of another stage of the plant for cooling the fluid thereof.

[0017] In the following, the term "users" will be used to indicate evaporators, or exchangers in general of the plant and assigned for such users.

[0018] The high stage 3 comprises a first compressor 5 or a set of first compressors, a first condenser 7 or a set of first condenser, at least a first receiver means 11, said set of user equipment 13 and a first duct 15 of an intermediate heat exchanger means 18; these elements are connected, via pipes, valves etc., to form the high stage cooling circuit in which circulates a respective cooling fluid consisting, for example in propane.

[0019] The first duct 15 may be connected in parallel to the set of user equipment 13.

[0020] The plant 1 is also provided with at least a low stage 20 comprising at least a second compressor 22 or a set of second compressors, a second duct 24 of the intermediate heat exchanger means 18, at least a second receiver means 26, a set of user apparatus 28 connected to form the low stage cooling circuit in which circulates a respective refrigerator fluid consisting, for example, in carbon dioxide; in the following the user apparatus are also indicated as the low stage user apparatus 28.

[0021] The intermediate exchanger is placed at a greater height with respect to the second receiver means 26 of the low stage 20 circuit.

[0022] In alternative, the invention provides that the high stage 3 can be completely free of user equipment 13 for example in the case in which such high stage is totally dedicated to the cooling of the refrigerating fluid of the low stage 20; in other words the user equipment can consist in the first duct 15 of the intermediate heat exchanger means 18 so that, in this case, is the only user.

[0023] The plant 1 is provided with pressure sensor means 30, for example placed into the low stage circuit 20 upstream of the second duct 24 for detecting the pressure of the low stage fluid.

[0024] The pressure sensor means 30 are connected to control means, for example of microprocessor, programmable type, and provided with analog and/or digital inputs for sensors or detectors and outputs for the control and the operation of the various elements controlled by said control means.

[0025] The plant 1 is provided with feeding means 31 controlled by the control means to feed the intermediate heat exchanger means 18 with a cooling fluid.

[0026] The control means are programmed to activate the feeding means 31 when said pressure of the fluid of idle low stage 20 reaches or exceeds a predetermined threshold value.

[0027] In said activation condition, the feeding means 31 are connected to a duct of the intermediate heat exchanger means 18 to feed said duct with a cooling fluid and to expand the latter for refrigerating the fluid of the low stage 20.

[0028] In particular, but not exclusively, said duct means of the intermediate heat exchanger means 18 connected to the feeding means 31 consists in the first duct 15 of the intermediate heat exchanger means 18 and the refrigeration cooling fluid adducted by the feeding means 31 consists in the fluid of the high stage 3 in the liquid state that is expanded by special members of the feeding means 31 in this first duct 15.

[0029] A simple alternative of the invention, not illustrated, provides that said duct of the intermediate heat exchanger means 18 connected to the feeding means 31 is run through by any refrigerating fluid which expands in it or by any low temperature carrier liquid assigned to cool such intermediate heat exchanger means and in particular the low stage fluid contained therein.

[0030] As illustrated in Figure 1, the first embodiment of the invention provides that the feeding means 31 and the expansion means include a safety compressor 40 whose input is connected to a first inlet 19 of the first duct 15 of the intermediate heat exchanger means 18 whose outlet is connected to an inlet of the safety condenser 41 the outlet of which is connected to the inlet of the first receiver means 11.

[0031] The outlet of the first receiver means 11 is connectable, by a first cut-off valve 42 and by a first expansion means 43 actuated by the control means, to the second inlet 21 of the first duct 15.

[0032] Said first duct 15, safety compressor 40, safety condenser 41, first receiver means 11, the first cut-off valve 42 and first expansion means 43 in the actuating condition operated by the control means, made the circuit of the feeding means 31 for the cooling of the fluid of the low stage 20.

[0033] This solution allows to use the fluid and many of the standard circuit elements of the high stage, for example the intermediate heat exchanger means 18, and allows at the same time to save the wear of the first compressor 5 and to save part of the energy necessary for the running of this latter because the safety compressor 40 is of lower power.

[0034] The plant comprises a first check valve 27 interposed and oriented between the outlet of the at least a first condenser 7 and the inlet of the first receiver means 11 and comprises a second check valve 44 interposed and oriented between the outlet of the at least one safety condenser 41 and the inlet of the first receiver means 11; these check valves prevent reflux of the high stage fluid.

[0035] The high stage 3 also comprises a second cut-off valve 23 interposed between the outlet of the first receiver means 11 and the first inlet 19 of the first duct 15 and a third cut-off valve 25 interposed between the second inlet 21 of the first duct 15 and the inlet of the at least one first compressor 5, where such second 23 and third 25 cut-off valves are actuated by the control means.

[0036] For example, during the operation of the safety compressor 40 for refrigerating the low stage, the third cut-off valve 25 is close actuated by the control means.

[0037] The plant comprises a fourth cut-off valve 29 for each possible user equipment 13. These fourth cut-off valves 29 are actuated to manage the production of cold in each of the user equipment 13.

[0038] In the above mentioned closing condition of the third cut-off valve 25, the first compressor 5 can cool the user equipment 13 whose fourth cut-off valves 29 are open.

[0039] In case of lack of the user equipment 13, it is also possible to eliminate the third cut-off valve 25 and replace it with a continuous length of duct so as to ensure the continuity of the connection between the second inlet 21 of the first duct 15 and the inlet of the first compressor 5.

[0040] It is thus possible to alternately operate the safety compressor 40 or the first compressor 5 for feeding the first duct 15 and cool the fluid of the low stage in the second duct 24 of the intermediate heat exchanger means 18.

[0041] The ducts and connections in the installation 1 are arranged in such a way that when it is active at least one of the first compressor 5, the fluid of the high stage 3 flows from the first inlet 19 to the second inlet 21 of the first duct 15; when the at least one safety compressor 40 is active, the fluid of the high stage 3 flows from the second inlet 21 to the first inlet 19 of the first duct 15.

[0042] In summary the cut-off valves 23, 25, 29, 42, actuated in a coordinated manner with the first compressor 5, for example allow to switch the high stage 3 in a cooling and pressure reduction condition of the fluid of the low stage 20.

[0043] It's important to observe that it is sufficient to equip this first embodiment with a small generator able to feed the small safety compressor 40, the control means, the remotely operated valves and the other electrically operated elements for ensuring the pressure control of the low stage also in case of electric power blackout.

[0044] The invention provides that the plant can be provided with an optional third duct 50 assigned to put in flow communication the top of the second receiver 26, or the outlet for the vapors or gases of the second receiver 26, with the duct connecting the outlet of the at least a second compressor 22 with the inlet of the second duct 24 of the intermediate heat exchanger means 18. This third duct 50 is of small inner lumen, for example the diameter of its inner lumen ranges from the half to one tenth of the average diameter, or minimum diameter, of the other ducts and tubes of the low stage 20. Surprisingly this third duct 50 provides a better operation of the plant, perhaps because it creates a small differential pressures inside the intermediate exchanger, low stage side, during the pressure control phases.

[0045] The method for controlling the pressure of a cooling fluid of an idle low stage of a multistage plant made according to one of the described embodiments, provides that in an condition in which the low stage 20 is idle and the plant pressure sensor means 30 detects and provides the control means with a pressure value of the fluid of the low stage higher than a predetermined threshold, to actuate, by means of said control means, the feeding means 31 to feed a refrigerant fluid of any nature in a duct of an intermediate heat exchanger means 18 assigned to the thermic exchange between the cooling fluids of a high and lower stages of the plant.

[0046] The feeding of the refrigerant fluid in the intermediate heat exchanger means 18 cools the cooling fluid of such low stage housed in a second duct 24 of the intermediate heat exchanger means 18 and being part of the cooling circuit of the low stage itself. Such cooling produces the reduction of pressure of the cooling fluid of the low stage.

[0047] In particular, the method provides to expand the cooling fluid of the high stage of the plant in a first duct 15 of the intermediate heat exchanger means 18 having the second duct 24 inserted in the cooling circuit of the lower stage 20.

[0048] When this condition ceases the method provides to deactivate, via said control means, the feeding means 31.

Claims

1. Pressure controlled multistage cooling plant having at least a high stage (3) comprising at least a set of first compressors (5), a set of first condensers (7), at least a first receiver means (11) and a first duct (15) of an intermediate heat exchanger means (18) mutually connected to form the high stage refrigeration circuit; said plant (1) being further provided with at least a low stage (20) comprising at least a set of second compressors (22), a second duct (24) of the intermediate heat exchanger means (18), at least a second receiver means (26), a set of low stage user apparatus (28) mutually connected to form the low stage refrigeration circuit, a control means for controlling various elements of the plant, feeding means (31) to feed the intermediate heat exchanger means (18) with a cooling fluid; said plant comprises pressure sensor means (30) assigned to detect the pressure of the fluid of the low stage (20) and connected to the control means configured to activate the feeding means (31) when said pressure of the fluid of the idle low stage (20) reaches or exceeds a predetermined threshold value; said feeding means (31) are activated and connected to a duct of the intermediate heat exchanger means (18) to feed in said duct a cooling fluid for cooling the fluid of the low stage (20) in a condition of activation of said feeding means (31); said duct of the intermediate heat exchanger means (18) that can be connected to the feeding means (31) consists of the first duct (15) of the intermediate heat exchanger means (18) and the cooling fluid feed by the feeding means (31) consists of the fluid of the high stage (3); said plant is characterized in that the feeding means (31) comprising at least a safety compressor (40), at least one safety condenser (41), a first cut-off valve (42) and a first expansion means (43); the inlet of the safety compressor (40) is connected to a first inlet (19) of the first duct (15) of the intermediate heat exchanger means (18) and the outlet of said safety compressor (40) is connected to an inlet of the at least one safety condenser (41) whose outlet is connected to the inlet of the first receiver means (11) whose outlet is connectable, by means of the first cut-off valve (42) and of the first expansion means (43) operated by the control means, to the second inlet (21) of the first duct (15), where said first duct (15), safety compressor (40), safety condenser (41), first receiver means (11), first cut-off valve (42) and first expansion means (43), in the condition of activation operated by the control means, carry out the circuit of the feeding means (31) for cooling the fluid of the low stage (20).

2. Plant according to claim 1 characterized in that the high stage (3) comprises a second cut-off valve (23) interconnected between the outlet of the first receiver means (11) and the first inlet (19) of the first duct (15) and a possible optional third cut-off valve (25) interconnected between la second inlet (21) of the first duct (15) and the inlet of the at least a first compressor (5), where said second (23) and optional third (25) cut-off valve are operated by the control means.

3. Plant according to claim 1 or 2 characterized in that it comprises a first check valve (27) interconnected between and oriented from the outlet of the at least a first condenser (7) to the inlet of the first receiver means (11) and it comprises a second check valve (44) interconnected between and oriented from the outlet of the at least a safety condenser (41) to the inlet of the first receiver means (11).

4. Plant according to any of claims 2 or 3 characterized in that it comprises a set of user equipment (13) and a set of corresponding fourth cut-off valves (29) operated to manage the cool production into each of the user equipment (13).

5. Plant according to claim 1 characterized in that the ducts and linkages of the plant (1) are arranged in a manner that, when at least one of the set of first compressors (5) is active, the fluid of the high stage (3) flows from the first inlet (19) to the second inlet (21) of the first duct (15); when the at least one safety compressor (40) is active, the fluid of the high stage (3) flows from the second inlet (21) to the first inlet (19) of the first duct (15).

6. Plant according to claim 1 characterized in that the control means is configured to operate at least a first compressor of the set of first compressors (5).

7. Plant according to claim 6 characterized in that it comprises a second cut-off valve (23) interconnected between the outlet of the first receiver means (11) and la first inlet (19) of the first duct (15), said second cut-off valve (23) being opened by the control means at least during the operation of at least one of the set of first compressors (5) and optionally it comprises a set of user equipment (13) and a set of corresponding fourth cut-off valves (29) operated to manage the cool production in each of the user equipment (13).

8. Plant according to any of the preceding claims characterized in that it comprises a third duct (50) connecting in flow communication the upper portion of the second receiver means (26) with the duct connecting the outlet of the at least one second compressor (22) with the inlet of the second duct (24) of the intermediate heat exchanger means (18).

9. Plant according to claim 8 characterized in that the diameter of the inner lumen of said third duct (50) ranges from the half to one tenth of the diameter of the lumen of the other ducts and tubes of the low stage (20).

10. Method for controlling the pressure of a fluid of an idle low stage of a multistage cooling plant of any of claims 1 - 7 characterized in that, in an idle condition of the low stage (20) and when the control means of the plant receives from the pressure sensor means (30) a detected pressure value exceeding a predetermined threshold, to operate, by means of said control means, the feeding means (31) to feed a cooling fluid into an intermediate heat exchanger means (18) belonging to the refrigeration circuits of the low stage (20) and of a high stage (3) of the multistage cooling plant and assigned at least to the heat exchange between the fluids of said low (20) and high (3) stages.

Ansprüche

1. Druckgesteuerte mehrstufige Kühlanlage, die mindestens eine Hochdruckstufe (3) aufweist, die umfasst: mindestens einen Satz erster Kompressoren (5), einen Satz erster Verflüssiger (7), mindestens ein erstes Aufnahmemittel (11) und eine erste Leitung (15) eines zwischengeschalteten Wärmetauschermittels (18), das zur Bildung des Hochdruck-Kühlkreislaufs beidseitig verbunden ist; wobei
die Anlage (1) weiterhin mit mindestens einer ersten Niederdruckstufe (20) ausgestattet ist, die umfasst: zumindest einen Satz zweiter Kompressoren (22), eine zweite Leitung (24) des zwischengeschalteten Wärmetauschermittels (18), mindestens ein zweites Aufnahmemittel (26), einen Satz Niederdruck-Benutzereinrichtungen (28), die zur Bildung des Niederdruck-Kühlkreislaufs beidseitig verbunden sind; ein Steuermittel zur Steuerung verschiedener Elemente der Anlage, Zuführmittel (31), um das zwischengeschaltete Wärmetauschermittel (18) mit einer Kühlflüssigkeit zu versorgen; wobei
die Anlage Drucksensormittel (30) umfasst, die zugeordnet sind, um den Druck der Flüssigkeit der Niederdruckstufe (20) zu erfassen, und die mit dem Steuermittel verbunden sind, das ausgestaltet ist, um die Zuführmittel (31) zu aktivieren, sobald der Flüssigkeitsdruck der Niederdruckstufe (20) im Ruhezustand einen vorher festgelegten Schwellenwert erreicht oder überschreitet; wobei
die Zuführmittel (31) aktiviert und mit einer Leitung des zwischengeschalteten Wärmetauschermittels (18) verbunden werden, um der Leitung eine Kühlflüssigkeit zur Kühlung der Flüssigkeit der Niederdruckstufe (20) in einem Aktivierungszustand des Zuführmittels (31) zuzuführen; wobei
die Leitung des zwischengeschalteten Wärmetauschermittels (18), die mit den Zuführmitteln (31) verbunden werden kann, aus der ersten Leitung (15) des zwischengeschalteten Wärmetauschermittels (18) besteht, und die Kühlflüssigkeitszufuhr durch die Zuführmittel (31) besteht aus der Flüssigkeit der Hochdruckstufe (3); und
die Anlage ist dadurch gekennzeichnet, dass die Zuführmittel (31) umfassen: mindestens einen Sicherheitskompressor (40), mindestens einen Sicherheitsverflüssiger (41), ein erstes Absperrventil (42) und ein erstes Expansionsmittel (43); wobei
der Einlass des Sicherheitskompressors (40) mit einem ersten Einlass (19) der ersten Leitung (15) des zwischengeschalteten Wärmetauschermittels (18) verbunden ist und der Auslass des Sicherheitskompressors (40) ist mit einem Einlass des mindestens einen Sicherheitsverflüssigers (41) verbunden, und dessen Auslass ist mit dem Einlass des ersten Aufnahmemittels (11) verbunden, und dessen Auslass ist mithilfe des ersten Absperrventils (42) und des ersten vom Steuermittel betriebenen Expansionsmittels (43) mit dem zweiten Einlass (21) der ersten Leitung (15) dort verbindbar, wo die erste Leitung (15), der Sicherheitskompressor (40), der Sicherheitsverflüssiger (41), das erste Aufnahmemittel (11), das erste Absperrventil (42) und das erste Expansionsmittel (43) - im aktiven Zustand betrieben vom Steuermittel - den Kreis des Zuführmittels (31) zur Kühlung der Flüssigkeit der Niederdruckstufe realisieren.

2. Anlage gemäß Anspruch 1, dadurch gekennzeichnet, dass die Hochdruckstufe (3) ein zweites Absperrventil (23) umfasst, das verschaltet ist zwischen dem Auslass des ersten Aufnahmemittels (11) und dem ersten Einlass (19) der ersten Leitung (15) und einem möglichen, optionalen dritten Absperrventil (25), das dort zwischen einem zweiten Einlass (21) der ersten Leitung (15) und dem Einlass des mindestens einen ersten Kompressors (5) verschaltet ist, wo das zweite (23) und das optionale dritte Absperrventil (25) vom Steuermittel betrieben werden.

3. Anlage gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, dass sie ein erstes Rückschlagventil (27) aufweist, das zwischen dem Auslass des mindestens einen ersten Kondensators (7) und dem Einlass des ersten Aufnahmemittels (11) verschaltet und an diesem ausgerichtet ist, und sie umfasst ein zweites Rückschlagventil (44), das zwischen dem Auslass des mindestens einen Sicherheitsverflüssigers (41) und dem Einlass des ersten Aufnahmemittels (11) verschaltet und an diesem ausgerichtet ist.

4. Anlage gemäß Anspruch 2 oder 3, dadurch gekennzeichnet, dass sie einen Satz von Benutzergeräten (13) und einen Satz entsprechender vierter Absperrventile (29) aufweist, die betrieben werden, um die Kälteerzeugung je in einem Benutzergerät zu steuern.

5. Anlage gemäß Anspruch 1, dadurch gekennzeichnet, dass die Leitungen und Verbindungsglieder der Anlage (1) derart angeordnet sind, dass die Flüssigkeit der Hochdruckstufe (3) vom ersten Einlass (19) zum zweiten Einlass (21) der ersten Leitung (15) fließt, wenn mindestens ein Kompressor des Satzes der ersten Kompressoren (5) aktiv ist; und die Flüssigkeit der Hochdruckstufe (3) fließt vom zweiten Einlass (21) zum ersten Einlass (19) der ersten Leitung (15), wenn der mindestens eine Sicherheitskompressor (40) aktiv ist.

6. Anlage gemäß Anspruch 1, dadurch gekennzeichnet, dass das Steuermittel ausgestaltet ist, um mindestens einen ersten Kompressor des Satzes der ersten Kompressoren (5) zu betreiben.

7. Anlage gemäß Anspruch 6, dadurch gekennzeichnet, dass sie ein zweites Absperrventil (23) aufweist, das zwischen dem Auslass des ersten Aufnahmemittels (11) und dem ersten Einlass (19) der ersten Leitung (15) verschaltet ist, wobei das zweite Absperrventil (23) zumindest während des Einsatzes von mindestens einem der Kompressoren des Satzes der ersten Kompressoren (5) vom Steuermittel geöffnet wird, und sie umfasst optional einen Satz von Benutzereinrichtungen (13) und einen Satz entsprechender vierter Absperrventile (29), die betrieben werden, um die Kälteerzeugung in je einer Benutzereinrichtung (13) zu steuern.

8. Anlage gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass sie eine dritte Leitung (50) aufweist, die den oberen Abschnitt des zweiten Aufnahmemittels (26) in Fließverbindung mit der Leitung verbindet, die den Auslass des mindestens einen zweiten Kompressors (22) mit dem Einlass der zweiten Leitung (24) des zwischengeschalteten Wärmetauschermittels (18) verbindet.

9. Anlage gemäß Anspruch 8, dadurch gekennzeichnet, dass der Durchmesser des inneren Hohlraums der dritten Leitung (50) zwischen der Hälfte und einem Zehntel des Durchmessers des Hohlraums der anderen Leitungen und Schläuche der Niederdruckstufe (20) liegt.

10. Verfahren zum Steuern des Flüssigkeitsdrucks einer Niederdruckstufe im Ruhezustand einer mehrstufigen Kühlanlage gemäß einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass es im Ruhezustand der Niederdruckstufe (20) und wenn das Steuermittel der Anlage vom Drucksensormittel (30) einen festgestellten Druckwert erhält, der einen vorher festgelegten Schwellenwert überschreitet, mithilfe des Steuermittels die Zuführmittel (31) betreibt, um eine Kühlflüssigkeit einem zwischengeschalteten Wärmetauschermittel (18) zuzuführen, das Teil des Kühlungskreislaufs der Niederdruckstufe (20) und der Hochdruckstufe (3) der mehrstufigen Kühlanlage ist und das zumindest dem Wärmeaustausch zwischen den Flüssigkeiten der Niederdruck- und Hochdruckstufen zugewiesen ist.

Revendications

1. Installation de refroidissement à plusieurs étages à pression régulée ayant au moins un étage haut (3) comprenant au moins un ensemble de premiers compresseurs (5), un ensemble de premiers condenseurs (7), au moins un premier moyen récepteur (11) et un premier conduit (15) d'un moyen échangeur de chaleur intermédiaire (18) mutuellement reliés pour former le circuit de réfrigération d'étage haut ; ladite installation (1) comportant en outre au moins un étage bas (20) comprenant au moins un ensemble de seconds compresseurs (22), un deuxième conduit (24) du moyen échangeur de chaleur intermédiaire (18), au moins un second moyen récepteur (26) et un ensemble d'appareils d'utilisateur d'étage bas (28) mutuellement reliés pour former le circuit de réfrigération d'étage bas, un moyen de commande pour commander divers éléments de l'installation, un moyen d'alimentation (31) pour alimenter en fluide de refroidissement le moyen échangeur de chaleur intermédiaire (18) ; ladite installation comprend un moyen capteur de pression (30) destiné à détecter la pression du fluide de l'étage bas (20) et relié au moyen de commande configuré pour activer le moyen d'alimentation (31) lorsque ladite pression du fluide de l'étage bas inactif (20) atteint ou dépasse une valeur de seuil prédéterminée ; ledit moyen d'alimentation (31) est activé et relié à un conduit du moyen échangeur de chaleur intermédiaire (18) pour alimenter, dans ledit conduit, un fluide de refroidissement pour refroidir le fluide de l'étage bas (20) dans un état d'activation dudit moyen d'alimentation (31) ; ledit conduit du moyen échangeur de chaleur intermédiaire (18) qui peut être relié au moyen d'alimentation (31) consiste en le premier conduit (15) du moyen échangeur de chaleur intermédiaire (18) et le fluide de refroidissement alimenté par le moyen d'alimentation (31) consiste en le fluide de l'étage haut (3) ; ladite installation est caractérisée par le fait que le moyen d'alimentation (31) comprend au moins un compresseur de sécurité (40), au moins un condenseur de sécurité (41), une première vanne d'arrêt (42) et un premier moyen de détente (43) ; l'entrée du compresseur de sécurité (40) est reliée à une première entrée (19) du premier conduit (15) du moyen échangeur de chaleur intermédiaire (18) et la sortie dudit compresseur de sécurité (40) est reliée à une entrée de l'au moins un condenseur de sécurité (41) dont la sortie est reliée à l'entrée du premier moyen récepteur (11) dont la sortie est apte à être reliée, à l'aide de la première vanne d'arrêt (42) et du premier moyen de détente (43) actionnés par le moyen de commande, à la seconde entrée (21) du premier conduit (15), ledit premier conduit (15), ledit compresseur de sécurité (40), ledit condenseur de sécurité (41), ledit premier moyen récepteur (11), ladite première vanne d'arrêt (42) et ledit premier moyen de détente (43), dans l'état d'activation actionné par le moyen de commande, constituant le circuit du moyen d'alimentation (31) pour refroidir le fluide de l'étage bas (20).

2. Installation selon la revendication 1, caractérisée par le fait que l'étage haut (3) comprend une deuxième vanne d'arrêt (23) interconnectée entre la sortie du premier moyen récepteur (11) et la première entrée (19) du premier conduit (15), et une éventuelle troisième vanne d'arrêt facultative (25) interconnectée entre la seconde entrée (21) du premier conduit (15) et l'entrée de l'au moins un premier compresseur (5), lesdits deuxième (23) et troisième (25), facultative, vannes d'arrêt étant actionnées par le moyen de commande.

3. Installation selon la revendication 1 ou 2, caractérisée par le fait qu'elle comprend un premier clapet de non-retour (27) interconnecté entre et orienté de la sortie de l'au moins un premier condenseur (17) vers l'entrée du premier moyen récepteur (11), et qu'elle comprend un second clapet de non-retour (44) interconnecté entre et orienté de la sortie de l'au moins un condenseur de sécurité (41) vers l'entrée du premier moyen récepteur (11) .

4. Installation selon l'une quelconque des revendications 2 ou 3, caractérisée par le fait qu'elle comprend un ensemble d'équipements d'utilisateur (13) et un ensemble de quatrièmes vannes d'arrêt correspondantes (29) actionnées pour gérer la production de froid dans chacun des équipements d'utilisateur (13).

5. Installation selon la revendication 1, caractérisée par le fait que les conduits et liaisons de l'installation (1) sont disposés de telle sorte que, lorsqu'au moins un parmi l'ensemble de premiers compresseurs (5) est actif, le fluide de l'étage haut (3) s'écoule de la première entrée (19) à la seconde entrée (21) du premier conduit (15) ; lorsque l'au moins un compresseur de sécurité (40) est actif, le fluide de l'étage haut (3) s'écoule de la seconde entrée (21) à la première entrée (19) du premier conduit (15).

6. Installation selon la revendication 1, caractérisée par le fait que le moyen de commande est configuré pour actionner au moins un premier compresseur de l'ensemble de premiers compresseurs (5).

7. Installation selon la revendication 6, caractérisée par le fait qu'elle comprend une deuxième vanne d'arrêt (23) interconnectée entre la sortie du premier moyen récepteur (11) et la première entrée (19) du premier conduit (15), ladite deuxième vanne d'arrêt (23) étant ouverte par le moyen de commande au moins pendant le fonctionnement d'au moins un parmi l'ensemble de premiers compresseurs (5), et facultativement, elle comprend un ensemble d'équipements d'utilisateur (13) et un ensemble de quatrièmes vannes d'arrêt correspondantes (29) actionnées pour gérer la production de froid dans chacun des équipements d'utilisateur (13).

8. Installation selon l'une quelconque des revendications précédentes, caractérisée par le fait qu'elle comprend un troisième conduit (50) reliant en communication fluidique la partie supérieure du second moyen récepteur (26) au conduit reliant la sortie de l'au moins un second compresseur (22) à l'entrée du deuxième conduit (24) du moyen échangeur de chaleur intermédiaire (18) .

9. Installation selon la revendication 8, caractérisée par le fait que le diamètre de la lumière interne dudit troisième conduit (50) se situe dans la plage allant de la moitié à un dixième du diamètre de la lumière des autres conduits et tubes de l'étage bas (20).

10. Procédé de régulation de la pression d'un fluide d'un étage bas inactif d'une installation de refroidissement à plusieurs étages selon l'une quelconque des revendications 1 à 7, caractérisé par, dans un état inactif de l'étage bas (20) et lorsque le moyen de commande de l'installation reçoit, en provenance du moyen capteur de pression (30), une valeur de pression détectée dépassant un seuil prédéterminé, l'actionnement, à l'aide dudit moyen de commande, du moyen d'alimentation (31) pour alimenter en fluide de refroidissement un moyen échangeur de chaleur intermédiaire (18) appartenant aux circuits de réfrigération de l'étage bas (20) et d'un étage haut (3) de l'installation de refroidissement à plusieurs étages et destiné au moins à l'échange de chaleur entre les fluides desdits étages bas (20) et haut (3).

Drawing