US1652163A - Refrigerating system - Google Patents

Description

Dec. 13, 1927.

w. H. CARRIER REFRIGERATING SYSTEM Filed July 28, 1925 Patented Dec. 13, 1927.-

UNITED STATES 1,652,163- PATENT OFFICE.

WILLIS H. CARRIER, OF ESSEX FELLS, NEW JERSEY, ASS IGNOR T0 CARRIER GI. NEERING CORPORATION, OF NEWARK, NEW JERSEY- nnrnrenna'rme sys'rnm.

Application filed July 28, 1925. Serial No. 46,568.

This invention relates to refrigerating systems and more particularly to improvements in purging and rectifying means for refrigcrating systems of the compression type which are operated at a pressure below atmospherie pressure in both the evaporator and condenser, the purging and rectifying means being for the purpose of removing air or non-condensible gas from the system at the commencement of the refrigerating operation and for automatically evacuating air or non-condensible gas from the system during the operation thereof, and also for automatically rectifying or purifying the volatile liquid refrigerant during the refrigerating operation. The Word gas as used in the following description is intended to signify either air or other non-condensible gas as distinguished from the condensible refrigerant vapor.

One object of the invention is to provide a practical and eflicient mechanism which operates automatically to separate the gas from the refrigerant vapor and discharge the same from the system during the operation of the refrigerating system with the minimum loss of the volatile refrigerant. Other objects of the invention areto provide an evacuating mechanism for the gas in which mixed gas and refrigerant vapor withdrawn from the condenser of the refrigerating system, are cooled in successive stages by a preliminary and a primary cooler, whereby the preliminary cooler, first condenses a considerable proportion of the V3- por out of its mixture and the primary cooler handles mainly non-condensible gas, so that after the condensing out of the vapor in the primary cooler, only a very small proportion of refrigerant vapor will remain with the gas; also to cool the mixed refrigerant vapor and gas withdrawn from the system in successive coolers in which cold'liquid refrigerant from the refrigerating system is employed as the cooling medium and flows through the coolers in succession. in a counter-current direction relative te the flow of the refrigerant vapor and-gas; also to construct and arrange the preliminary cooler, in which the cold liquid refrigerantis last used, so that it functions also as a rectifier for purifying or rectifying the liquid refrigerant; also to provide regulating means whereby a slight reduction in pressure in the condenser after it has been cooled for condensing the refrigerant vapor out of the gas, and in which a vacuum pump is connected with said vacuum reservoir for purging the same and discharging the vapor and gas through a final cooler to a separating device from which the gas is permitted to escape while the condensate of the refrigerant vapor is returned to the refrigerating system; and also to improve refrigerating systems in the other respects hereinafter described and set forth in the claims.

In the accompanying drawings:

Fig. 1 is a diagrammatic view of a compresslon refrigerating system provided with gas purging and refrigerant rectifying means embodying my invention.

Fig. 2 is. a sectional view of the regulating valve or device for regulating the flow of the vapor and gas through the primary cooler.

Fig. 3 is a similar view of the evacuator stop valve for preventing back fiow of vapor or entrance of air or gas into the system.

A represents the evaeuator, B the compressor, and C the condenser of a compression refrigerating system in which a volatile liquid refrigerant is vaporizedin the evaporator by heat abstracted from the medium being cooled. The compressor withdraws the vapor from the evaporator and delivers it at a higher pressure into the condenser where the vapor is liquefied, and the liquid refrigerant is returned to be again vaporized'm the usual cycle of operations in such systems. The gas purging and refrigerant reetifying means are illustrated in connection with a refrigerating system in which a centrifugal compressor is employed which mainrator and condenser are operated at pressures below atmospheric arts may be of any suita 1e construction,

at referably the evaporator is constructed so hat the refrigerant liquid is caused to flow in thin films over unsubmerged tubes or passages through which the water or medium being cooled passes, and the condenser is constructed so that the refrigerant vapor, after passing through successive condensing stages or portions, enters an ascending space in the condenser, from the upper portion of which some of the dense vapor and any noncondensible gas mixed therewith may be withdrawn by the purging means.

10 represents a vacuum tank or I'GSCI'YOlI and 11 represents a vacuum pump connected therewith for exhausting vapor and gas from the reservoir and creating a partial vacuum therein. A lower pressure is maintained in the vacuum tank than in the condenser, with which the tank is preferably connected at the upper end of the ascending space 12 of the condenser, by a passage or connections whereby the dense vapor and gas in the space 12 of the condenser are withdrawn therefrom. Inter-posed in said passage or connections are a preliminary cooler 13 and a primary or main cooler 14 by which the vapor and as are successively cooled on their way to t e vacuum tank for condensing or liquefying the vapor to permit the separation thereof from the gas. As represented in the diagrammatic drawing, the vapor and gas passage from the condenser to the vacuum tank comprises a conduit 15 connected with the condenser, a cooling coil 16 located in the cooling chamber of the preliminary cooler 13, a conduit 17, a coil 18 located in the coolin chamber of the primary cooler 14, a conduit 19, a regulating valve or device 20, a conduit 21, an evacuator stop valve22 and a conduit 23. It will be understood, however, that the coils 16 and 18 or passages for the vapor and gas through the coolers 13 and 14, the regulating device and the evacuator stop valve may be arranged and connected with each other and with the condenser and vacuum tank or source of vacuum in any other suitable way adapted to permit the passage or flow of the vapor and gas from the condenser to the vacuum source and cause the vapor and gas to be first cooled by the preliminary cooler 13, then by the main or primary cooler 14 and thereafter pass through the regulating and evacuator stop valves or devices to the vacuum producing device.

In the passage, preferably between the preliminary and primary coolers 13 and 14, 1s a suitable restriction 25 adapted to restrict or reduce the flow of the vapor and gas, and the regulating valve or device 20 cooperates with this restriction to maintain a desired low difference between the pressures at the entrance and exit sides of the ressure. These primary cooler and a gentle or moderate flow of the vapor and gas through the cooler.

The regulating device or valve 20 shown in the drawings, see Fig. 2, has a casing 26 which is divided by a diaphragm 27 into high and low pressure chambers 28 and 29. The low pressure chamber 29 connnumcates with the vapor and gas passage 19 leading from the exit of the primary cooler 14, and a pressure connection 30 leads from the vapor and gas passage in ad ance of the restriction 25 to the high pressure chamber 28 of the regulating device so thatthe diaphragm is subjected on'opposite sides to the differential pressures existing in the vapor and gas passage at opposite sides of the restriction 25, and preferably in advance of the restriction and at the exitof the primary cooler. A valve plug 31 in the regulating device cooperates with a fport in the casing 26 to prevent the exit 0 the vapor and gas from the low pressure chamber 29 of the regulating device. A suitable spring 32 acts on the valve in conjunction with the low fluid pressure in the chamber 29 and in opposition to the higher pressure in the other chamber 28 of the regulating device, tending to open the valve and permit the vapor and gas to discharge past the valve from the regulating device. The valve is adapted to close and stop the discharge of the vapor and gas when the pressure in the high pressure chamber 28 exceeds the combined opposing fluid and spring pressure, and to open and permit the flow of the vapor and gas past the valve when the combined pressure of the spring 32 and of the fluid in the low ressure chamber 29 exceeds the pressure in the high pressure chamber 28. The pres sure of the spring can be regulated by a suitable adjusting nut or device 33 so that the valve is adapted to operate in accordance with a predetermined desired low difference between the pressures in the two chambers 28 and 29 of the regulating device. The regulating device is designed so as to maintain a small difference between the V ressures at the entrance and exit sides 0 the primary cooler and a very slow or entle flow of the vapor and gas throng the cooler. If no non-condensible gas is withdrawn from the condenser C, the consequent greater condensation of the vapor in the primary cooler 14 will cause a reduction in pressure in the low pressure chamber 29 of the regulating device sufiicient to close the valve, thereby stopping the exhaustion oi vapor from the condenser.

The evacuator stop valve shown, see Fig. 3, is similar to the regulating valve or device, except that the stop valve is provided with an additional spring 34 which tends to close the valve in opposition to the spring 35 corresponding to the spring 32 in the regulating device, and in the evacuator stop valve, the pressure of the vapor in the casing of the preliminary cooler 13 acts on the diaphragm in a direction to close the valve, while the pressure in the vapor and gas passage between the primary cooler and the vacuum tank acts on the opposite side of the diaphragmtending to open thevalve. The spring 34 is much stronger than the spring '35, so that this valve is adapted to close when the pressure of the vapor and gas and the spring 35 are not sufiicient to overcome the opposing pressure of the spring 34 and the va or in thepreliminal'y cooler.

Col liquid refri erant from the refrigerating system is pre erably employed for cooling the vapor and as in the coolers, and preferably the liquid refrigerant is passed through the rimary and reliminary coolers in the or or named an in a counterflow direction to the passage of the vapor and gas through these coolers so that a lower temperature prevails in the primary cooler than in the preliminary cooler. The preliminary and primary coolers are also connected for the return of refrigerant vapor generated in them to the evaporator or other suitable low pressure portion of the refrigerating system. Inthe constructionillustrated in the.

drawings, the purging mechanism is provided with a third or final cooler 40 for a purpose hereinafter explained, and this cooler is preferably cooled by the liquid refrigerant before the latter passes to the primary cooler.

For supplying the cooling liquid to the coolers in the arrangement illustrated, an open ended stand pipe 41 is provided inside of the evaporator A, and the liquid refrigerant discharges into this stand pipe from the liquid refrigerant distributing tray or device of the evaporator. the stand pipe connectsby a pipe or passage 42 to the casing or liquid chamber of the final cooler 40, from which the liquid refrigerant flows through a passage 43 into the casing or liquid chamber of the primary cooler 14. From the latter, the liquid refrigerant overflows into a pipe or passage 44 extending up into the primary cooler and flows therefrom through a pipe or passage 45 and a rectifier check valve 46 of suitable construction into the casing or liquid chamber of the preliminary cooler 13. The liquid refrigerant is adapted to overflow from the stand pipe 41 which maintains the required liquid level in the coolers 40 and'14. The

upper ends of the liquid chambers of the several coolers communicate with the evaporator A for the return thereto of refrigerant vaporized in the coolers. As shown, a passage 47 connects the upper ends of the easings of the preliminary and primary coolers, and the latter communicates with the upper end of thefinal cooler casing 40, which connects by a vapor return passage 48 to the The lower end of evaporator, so that any refrigerant which is vaporized in the coolers flows back to the evaporator.

A hand operated shutoff valve 49 in the vapor return passage 47 from the preliminary cooler is adapted to be set to restrict the discharge of vapor from this cooler so as to maintain vapor pressure on the liquid 1n the preliminary cooler. This restriction valve and the rect fier check valve 46 cooperate to vary or regulate the level of the liquid refrigerant in the preliminary cooler so as to expose a greater or less area of the coil 16 in this cooler to the li uid refrigerant, depending upon the rapi it of vaporization and the vapor pressure in t is cooler. When, for example, the liquid refrigerant is com paratively free from oil or other impurities, the vaporization thereof will be rapid and the vapor pressure will increase in the liquid chamber, and acting on the liquid, will close the check valve 46 and shut off further admission of liquid refrigerant to the preliminary cooler. thereby lowering the level of the liquid refrigerant in the preliminary cooler and reducing the amount ex osed to the coil action is regulated and kept substantially uniform notwithstanding the variations in the purity of the refrigerant.

Preferably, the lower end of the casing or liquid chamber of the preliminary cooler and rectifier connects with a settling chamber 50 which receives the impure liquid from the cooling chamber and is adapted to be heated by an electric or other suitable heating element 51 for raising the temperature of the impure refrigerant in this settling chamber ,4

to vaporize the refrigerant so as to prevent loss of the same when the settling chamber is drained. The settling chamber is provided with a drain cook 52 which can be opened from time to time, as may be necessary, to drain oflf the oil or other impurities. The heater 51 is intended to be used only just prior to each draining off of the impurities.

The non-condensible gas with the small proportion of refrigerant vapor remaining therewith after the condensations in thecoolers 13 and 14 will collect in the vacuum tank so long as the pressure in the latter remains sufliciently below the condenser pressure to draw the vapor and gas thereconnects with aseparating chamber 56 in which the liquid collects and from which the non-condensible gas is adapted to escape through a vent pipe 57, preferably provided with a suitable check valve 58 adapted to be opened by the gas pressure in the separating chamber when said pressure builds up a predetermined amount above atmospheric pressure. Preferably, an atmospheric cooling coil 59 is connected between the vacuum pump and the final cooler 40 for partially cooling the gas and vapor before it enters the final cooler and ensuring the required low temperature of the gas and vapor. 60 and 61 represent hand shut oll' valves in the discharge passages from the vacuum tank and vacuum pump respectively.

The refrigerant liquid condensed from the vapor and gas by the preliminary and primary coolers 13 and 14 is returned to the refrigerating system through suitable return connections 62 and 63 preferably leading from the vapor and gas passage at the opposite sides of the restriction 25, and the liquid recovered in the final cooler 40 is returned through a return passage 64 leading from the separating chamber 56 and provided with a valve 63 which can be opened from time to time by hand, or if referred, can be operated automatically, as y a float in the separating chamber. Preferably, these liquid refrigerant return connections lead to a separating chamber or device 65 adapted to separate any water of eondensation from the refrigerant. This water separating device, as shown, is provided with weirs arranged, for instance, as disclosed in my application, Serial No. 585,999, filed September 2, 1922, to skim the water off of the refrigerant liquid. The water is discharged from the separator through a drain cook 66, while the liquid refrigerant is discharged through a plpe or passage 67 into the liquid trap of the condenser C or other suitable part of the liquid line of the refrigerating system.

68 represents a bypass pipe or assage which connects the portions 15 and 23 of the vapor and gas ass-age, and is normally closed by a shuto valve 69. By opening this valve 69, closing a shutoff valve in the passage 15 and starting the vacuum pump 11, the vapor and gas can be drawn from the condenser and bypassed around the coolers 13 and 14 and directly discharged from the system. This is done to purge the refrigerating system of air and produce the necessary vacuum therein to start the refrigeratin operation. After the system is purge the valve 69 is closed and the valve 0 opened, when the pur ing means operate automatically as first exp ained.

, claim as my invention:

1. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a passage and means for withdrawing vapor and non-condensible gas from the condenser, a cooler having provision for cooling the vapor and gas flowing through said passage to condense the vapor, regulating mechanism which is controlled by the difference in pressures in said passage at the entrance and exit sides of said cooler and maintains a low difference in said pressures and regulates the flow through said passage, and means for the relief of the non-condensible gas.

2. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a passage and means for withdrawing vapor and non-condensible gas from the condenser, a cooler having rovision for cooling the vapor and as owing through said passage to con ease the vapor, a restriction in said passage at the entrance side of said cooler, a regulating device cooperating with said restriction to maintain a low difference in pressures in said passage at opposite sides of said restriction and regulate the flow through said passage, and means for the relief of the non-condensible gas.

3. In a refrigerating system, the combination with the condenser for "the volatile liquid refrigerant, of a passage and means for withdrawing va or and non-condensible gas from the con enser, a cooler having provision for cooling the vapor and gas flowing through said passage to condense the vapor, regulating mechanism which is controlled by the difference in pressures in said passage at the entrance and exit sides of said cooler and closes said passage to stop the flow therethrough when no non-condensible gas is present owing to the decrease in pressure due to the greater condensation of vapor by the cooler, and means for the relief of the non-condensible gas.

4. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a passage and means for withdrawing vapor and non-condensible gas from the condenser, a primary cooler having rovision for cooling the vapor and gas flowing through said passage to condense the vapor, regulating mechanism which is controlled by the difference in pressures in said passage at the entrance and exit sides of said cooler and maintains a. low difierence in said pressures and regulates the flow through said passages, a preliminary cooler for condensing out va or prior to the entrance of the vapor an gas to said rimary cooler so that said primary cooler andles a greater proportion of non-condensib'le gas, and means for the relief of the non-con- ;densible gas.

5. A refrigerating system according to claim I. characterized by the fact that cold refrigerant from the refrigerating system is em loyed as the cooling medium in the coo er. I a

6. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a passage and-means for cansing vapor and non-condensible gas to flow from said condenser through said passage, a cooler for condensing vapor from said vapor and gas, regulating mechanism which operates in response to pressure differences in said passage to maintain a low difference in pressure in said passage at the entrance and exit sides of said cooler. and regulates the flow through the passage, and means-for the relief of t e non-condensible gas.

7. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of apassage and means for causing vapor and non-condensible gas to flow fromsaid condenser through said passage, a primary cooler for condensing vapor from said vapor and gas, a preliminary-cooler for condensing out vapor prior to the entrance of the vapor and gas to said primary cooler so that said primary cooler handles a greater proportion of non-condensible gas, regulating mechanism which operates in response to pressure differences in said passage to regulate the flow through the passage, means for utilizing cold liquid refrigerant from the refrigerating system in succession in said primary and preliminary coolers as the coohng medium. thereof, and means for the relief of the-non-condensible gas.

8. A refrigerating system according to claim 4 comprising in the combination means for returning to the system the condensate from said passage at both the primary and preliminary coolers.

9. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a passage and means for withdrawing vapor and non-condensible gas from the condenser, a cooler having provision for cooling the vapor and gas flowing through said passage to condense the vapor, regulatin mechanism which is controlled by the di erence in pressures in said assage' at the entrance and grit sides of sai cooler and maintains a lowdaiference in said pressures and regulates the flow through said passage, means for employing cold liquid refrigerant from the refrigerating system in said cooler for cooling the vapor and nonfor withdrawing vapor and non-condensible gas from the condenser, a primary cooler for condensing vapor from said vapor and gas, regulating mechanism which maintains a low difference between the pressures in said passage at the entrance and exit sides of said cooler and regulates the flow throu 11 said passage, a preliminary cooler.for con ensing out vapor prior to the entrance of the vapor and gas to said primary cooler so that the primary cooler handles a greater proportion of non-condensible gas, means for utilizing cold liquid refrigerant from the refrigerating system in succession in said primary and preliminary coolersas the cooling medium thereof, vapor return connections from the liquid refrigerant chambers of said coolers to a low pressure part of the refrigerating system, and means for the relief of the noncondensible gas.

11. A refrigerating system according to claim 10 comprising in the combination means for heating the liquid refrigerant in the preliminary cooler for rectifying the refrigerant.

12. A refrigerating system according to claim 10 comprising in the combination regu lating means in the li uid refrigerant supply to the preliminary coo er and in the vapor re-' turn connection from said cooler for controlling the rectlfying action thereof.

13. In a refrigerating system,the combi- I nation with the condenser for the volatile liquid refrigerant, of .a passage and means for withdrawing vapor and non-condensible gas from the condenser, a cooler having provision for cooling the vapor and gas flowing through said passage to condense the vapor, a restriction in said passage at the entrance side of said cooler,'a regulating device coopcrating with said restriction to maintain a low difference in pressures in said passage at opposite sides of said restriction and regulate the flow through said passage, connections for returning the condensate to the stem from said passage at opposite sides 0 said restriction, and means for the relief of the non-condensible gas.

14. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a passage and means for withdrawing vapor and non-condensiblc gas from the condenser, a cooler having provision for cooling the vapor and gas flowing through said passage to condense the vapor, a restriction in said passage, a valve regulating the flow through said passage, and controlling means for said valve responsive forto the differential pressures in said passage at opposite sides of said restriction, and means for the relief of the non-condensible as. g 15. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a vacuum pump, and a passage connected w th the pump and with the condenser for withdrawing vapor and non-condensible gas from the condenser, a primary cooler for cooling the vapor and gas flowing through said passage from the condenser to said pump to condense the vapor, a final cooler for cooling the vapor and gas discharged from said pump, connections for returning the condensate from said primary cooler to the system, connections for return ing the condensate from said final cooler to the system and means for the relief of the non-condensible gas from said return con nection from said final cooler.

16. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a vacuum pump and a passage connected with the pump and with the condenser for withdrawing vapor and non-condensihle gas from the condenser, a primary cooler for cooling the vapor and gas flowing through said passage from the condenser to said pump to condense the vapor a separating chamber, a passage connect ng the pump discharge with said separatlng chamber, a cooler for the vapor and gas be tween said pump and said separating chamoer, means for the relief of non-condensible gas from said separating chamber, and connections for returning the condensate from said primary cooler and from said separating chamber'to the system.

17. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a vacuum pump and a passage connected with the pump and with the condenser for withdrawing vapor and non-condensible gas from the condenser, a primary cooler for cooling the vapor and gas flowing through said passage from the condenser to said pump to condense the vapor, at separating chamber, a passage connecting the ump discharge with said separating cham er, a cooler for the vapor and gas between said pump and said separating chamber, means for the relief of non-condensible gas from said separating chamber, connections for returning the condensate from said primary cooler and from said separating chamber to the system, and a device interposed in said connections for separating water from said condensate.

18. In a refrigerating system, the combination with the condenser for the volatile liquid refrigerant, of a vacuum tank and a assage connecting the same with the conenser for withdrawing vapor and non-condensible gas from the condenser, a cooler for cooling the vapor and gas flowing from the condenser to said tank to condense the vapor, a connection for the return of the condensate from said cooler to the system, a pump for exhausting said tank, a separating chamber, a passage connecting the pump discharge with said separating chamber, a cooler for the vapor and gas between said pump and said separating chamber, means for the relief of non-condensible gas from said separating chamber, and connections for returning the condensate from said separating chamber to the system.

19. In a refrigerating system, the combination with a condenser for the volatile refrigerant, of a passage and means for withdrawing vapor and gas from the condenser, two coolers through which the vapor and gas pass in succession for condensing the vapor out of the gas, a restriction in said passage between said coolers and a pressure actuated valve in said passage beyond said second cooler for controlling the flow of vapor and gas through said passage, and a pressure connection from said passage at the inlet side of said restriction, said valve being actuated to regulate the flow of vapor and gas by the differential action thereon of the pressures in said passage and in said pressure connection. 7

20; In a refrigerating system, the combination with a condenser for the volatile refrigerant, of two chambers to which cold liquid refrigerant is delivered, vapor return connections from the upper portions of said chambers to a low pressure portion of the system, a passage through which vapor and gas are withdrawn from the condenser and includin two condensin portions arranged to be coo led by the liquirfrefri erant in said chambers, a restriction in sai passage between said coolers and a pressure actuated valve in said passage beyond said second cooler for controlling the flow of vapor and gas through said passage, and a pressure connection from said passage at the inlet side of said restriction, said valve bein actuated to regulate the flow of vapor and gas by the differential action thereon on the pressures in said passage and in said pressure connection.

21. In a refrigerating system, the combination with a condenser for the volatile refrigerant, of two chambers to which cold liquid refrigerant is delivered in succession, vapor return connections from the upper portions of said chambers to a low pressure ortion of the system, a passage through w ich vapor and gas are withdrawn from the condenser and including two condensing portions arranged to be cooled by the liquid refrigerant in said chambers and through which vapor and gas pass in succession in a counterflow direction to the flow of refrigerant liquid, a restriction in the vapor resome turn connection betweenffsaid chambers, means for returning, the condensate from vsaid condensingportio'ns to the li uid cir-,

cuit of the refrigerating system, an a regulating device" in the hqi'ndfsu'pply connection to said second chamber for regulating the level of liquid thereinto control evaporation therein. I f

22. In a refrigerating system, the cornfination with a, condenser for the v0latile*-re- :Erigerant, of a passage through which vapor and non-condensible gas are drawn from the system and which includes'a coolin ele z ment, a pressure reducing device in sai passage, means for cooling-said cooling element, a differential regulating valve in said passage adapted to be opened by pressure from said passage at the low pressure side of said pressure reducingv device, and to be 20 closed by pressure from the passage at the high side\ of reducing d v e In" combination with arefrigerating system employing a volatile liquid refrigerant, a passage connecting a portion of the system containing refrigerant vapor with a of lower pressure and adated to withdraw vapor and non-condensi le gas iron the system, a cooler adapted to cool and gas flowing through said paseondense thevapor, regulating mechble gas.

' WILLIS H. CARRIER.

n fl cfie to automatically main ,tam a jl'owdifl'erenbe between the pressures

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