JP4023458B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger that cools air in a freezer compartment by latent heat of vaporization of refrigerant, and particularly relates to the performance of distributing refrigerant flowing out from an inlet side header tank into a plurality of flat tubes.

  In this type of heat exchanger, the operating temperature range for cooling the air is used in a low temperature range of 0 to −30 ° C., so the flow rate of refrigerant flowing through the heat exchanger is extremely small. Therefore, the gas-liquid separation of the refrigerant that has flowed into the header tank becomes significant, so that the distribution performance of the refrigerant flowing out to the plurality of flat tubes is deteriorated.

  Therefore, as disclosed in Patent Document 1, the applicant arranges a plurality of flattened tubes in which the refrigerant flows inside and a plurality of return flat tubes in which the refrigerant flows in the opposite direction to the plurality of flattened tubes in the width direction. In a heat exchanger comprising a core body and an upper header tank and a lower header tank at the upper and lower ends of the core body, the upper header tank has an inner space height dimension (H1) in the tank. An insertion allowance (h) having a height within a predetermined range is provided to connect the inlet end of the flat tube, and the lower header tank has a predetermined height relative to the internal space height (H2) in the tank. An adjusting member having a hole diameter (d) within the range is provided.

Thereby, the distribution performance of the refrigerant flowing from the upper and lower header tanks to the inlet ends of the flat tubes and the return flat tubes is improved by equalizing the deviation of the liquid-phase refrigerant in the header tank. (See, for example, Patent Document 1).
Japanese Patent Application No. 2003-376074

  However, according to the above-mentioned Patent Document 1, it is effective when the heat exchanger is arranged in the vertical direction, and when it is arranged in the horizontal direction, there is a problem that the distribution performance of the refrigerant flowing out into the flat tube is lowered. is there.

  Accordingly, an object of the present invention is to take the above-mentioned points into consideration, and by distributing the liquid-phase refrigerant separated in the header tank to the inlet ends of a plurality of flat tubes without uneven distribution, An object of the present invention is to provide a heat exchanger capable of improving the cooling performance.

In order to achieve the above object , the following technical means are adopted. That is, in the first aspect of the invention, the plurality of flat tubes (133) in which the refrigerant flows in the horizontal direction and the inlet ends of the plurality of flat tubes (133) are arranged in the longitudinal direction. In the heat exchanger horizontally provided with an inlet side header tank (134) and an outlet side header tank (136) in which outlet ends of a plurality of flat tubes (133) are arranged in the longitudinal direction,
The inlet-side header tank (134) includes an inlet pipe (13a) into which refrigerant flows, and an inlet pipe (13a) between the outlet end of the inlet pipe (13a) and the inlet ends of the plurality of flat tubes (133). 13a) and a partition member (135) for damming the refrigerant flowing in from the inlet pipe (13a). After the refrigerant flowing from the inlet pipe (13a ) is once blocked by the partition member (135) , a plurality of flat tubes ( 133) is configured to flow out to the inlet end.

  According to the first aspect of the present invention, the refrigerant flowing into the inlet-side header tank (134) is blocked, so that the liquid-phase refrigerant distributed to the inlet ends of the plurality of flat tubes (133) can be obtained. Since the bias can be prevented, it is distributed almost evenly. Thereby, the cooling performance of the heat exchanger can be improved.

Also, specifically, that the partition member (135) is provided in the internal space of the inlet side header tank (134), it can be dammed before flowing to the inlet end of the plurality of flat tubes (133) . Thereby, since the bias of the liquid-phase refrigerant distributed to the inlet ends of the plurality of flat tubes (133) can be prevented, it can be distributed almost evenly.

In the invention according to claim 2 , the partition member (135) is configured such that the upper end of the partition member (135) maintains the horizontal direction when the inlet header tank (134) is inclined with respect to the longitudinal direction thereof. It is characterized by being configured.

According to the second aspect of the present invention, for example, in a heat exchanger mounted on a refrigeration vehicle, when the vehicle is tilted, the heat exchanger installed in the horizontal direction is also tilted. Therefore, in the present invention, the liquid phase surface in the inlet side header tank (134) is configured so that the upper end of the weir is maintained in the horizontal direction even when the inlet side header tank (134) is inclined in the longitudinal direction. However, since the upper end of the partition member (135) is maintained so as to correspond to the liquid phase surface, it is possible to prevent the deviation of the liquid refrigerant distributed to the inlet ends of the plurality of flat tubes (133). it can.

In the invention according to claim 3 , the partition member (135) has a communication hole (135a) that communicates the outlet end of the inlet pipe (13a) and the inlet ends of the plurality of flat tubes (133) in the longitudinal direction. ) Is provided. According to invention of Claim 3 , the refrigerant | coolant which flowed in from inlet pipe (13a) flows with a bias | inclination in the inlet side header tank (134) by the inertial force at that time. Therefore, the communication holes (135a) are provided at locations where there is little bias, thereby preventing the refrigerant flow from being biased.

In the invention described in claim 4 , the inlet ends of the plurality of flat tubes (133) are arranged in a line so that the lower ends thereof are in contact with the lower ends in the inlet-side header tank (134). Yes. According to invention of Claim 4 , the liquid phase refrigerant | coolant in an inlet side header tank (134) can be reliably flowed out to a flat tube (133).

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means of embodiment mentioned later.

(First embodiment)
Hereinafter, a heat exchanger according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a configuration of a refrigeration vehicle 1 to which the present invention is applied, and FIG. 2 is a schematic diagram showing an overall configuration of a refrigeration cycle apparatus 5 mounted on the refrigeration vehicle 1. FIG. 3 is a perspective view showing a door portion of the refrigerator 1 shown in FIG. First, as shown in FIG. 1, the freezer 1 is provided with a freezer 2 at the rear of the cab.

  The freezer 2 is a space for storing an object to be stored such as frozen food. Opening doors 3 and 4 for opening and closing an opening 18 for carrying in or out the object to be stored are provided at the rear of the freezer 2. ing. A well-known refrigeration cycle device 5 that cools the air in the freezer 2 is mounted on the front portion of the refrigerator 1. As shown in FIG. 2, the refrigeration cycle apparatus 5 includes a compressor 6 that compresses and discharges a refrigerant to a high temperature and a high pressure, and the compressor 6 is used for traveling via an electromagnetic clutch 7 as is well known. It is driven by the vehicle engine 8.

  The gas refrigerant compressed to high temperature and high pressure by the compressor 6 flows into the condenser 9. As shown in FIG. 1, the condenser 9 is installed at a lower part of the vehicle floor, and cools and condenses the internal gas refrigerant with cooling air blown by the electric condenser fan 10. And the receiver 11 is provided in the refrigerant | coolant exit side of the condenser 9, and while condensing the refrigerant | coolant condensed by the receiver 11 into a gaseous-phase refrigerant | coolant and a liquid phase refrigerant | coolant, a liquid phase refrigerant | coolant is stored.

  A decompression means 12 for decompressing the liquid refrigerant from the receiver 11 is provided on the outlet side of the receiver 11, and the low-pressure gas-liquid two-phase refrigerant decompressed by the decompression means 12 is a heat exchanger as a refrigerating evaporator. Evaporate at 13. An accumulator 14 is provided between the outlet side of the refrigeration evaporator 13 and the suction side of the compressor 6.

  The accumulator 14 performs gas-liquid separation of the refrigerant that has passed through the refrigeration evaporator 13, stores the liquid-phase refrigerant, and sends the gas-phase refrigerant to the compressor 6 side. Further, in the refrigeration cycle apparatus 5, a bypass flow that directly communicates between the discharge side (high pressure side) of the compressor 6 and the upstream side portion (low pressure side) of the refrigeration evaporator 13 on the leeward side of the decompression means 12. A path 15 is provided, and an electromagnetic valve is installed as a defrost valve 16 for opening and closing the flow path. The bypass flow path 15 is a path that guides the high-temperature refrigerant (hot gas) on the high temperature side directly to the refrigeration evaporator 13 by bypassing the condenser 9 and the decompression means 12, and the defrost valve 16 is hot to the bypass flow path 15. This is a solenoid valve for switching between the case of flowing gas and the case of not flowing gas.

  As will be described in detail later, the freezing evaporator 13 cools the air in the freezer 2 by the latent heat of vaporization of the refrigerant, and is housed in the cooling unit 130, above the front side of the vehicle in the freezer 2. It is installed at the site. In the freezer 2, an electric refrigeration fan 17 that blows air toward the refrigeration evaporator 13 is provided adjacent to the refrigeration evaporator 13.

  The refrigeration fan 17 sucks the air in the freezer 2, passes the refrigeration evaporator 13 and cools it, and then blows cold air into the freezer 2 again. The refrigeration fan 17 operates regardless of the operation of the engine 8.

  Further, when the open / close doors 3 and 4 installed at the rear part of the freezer 2 are opened, as shown in FIG. 3, an opening 18 for carrying in and out the frozen material is formed at the rear part of the freezer 2. A blower 19 for forming an air curtain is installed below the opening 18, that is, outside the freezer 2, at a position below the open / close doors 3 and 4.

  The blower 19 includes two cross flow fans 20 and 21 arranged along the width direction of the opening 18 at the lower part of the opening 18. As is well known, when the multi-blade cylindrical fans (impellers) 20a and 21a are rotated, the cross flow fans 20 and 21 allow air to pass through the cross section perpendicular to the fan shaft.

  Incidentally, the cross flow fans 20 and 21 are rotatably accommodated in a casing (not shown), and the casing is held and fixed to the vehicle body of the refrigerator 1 via an appropriate attachment means (not shown). Further, a blowout duct 21d (the blowout duct on the fan 20a side is not shown in FIG. 3) that blows out the blown air (outside air) of the fans 20a and 21a is opened upward in the casing. Further, the blowout duct 21d is formed over the entire length in the width direction along the width direction of the opening 18.

  Further, motors 20e and 21e for rotationally driving the fans 20a and 21a are installed on the side portions of the casing. With such a configuration, the air curtain is formed by blowing the outside air from the lower side of the opening 18 toward the upper side (the direction of arrow a shown in the drawing) by the blower 19. This prevents high temperature outside air from entering the inside of the freezer 2, and the cold air inside the freezer 2 flows in the direction of the arrow b shown in the figure without leaking outside.

  Next, the configuration of the refrigeration evaporator 13 that is a heat exchanger that is a main part of the present invention will be described with reference to FIGS. 4 is a perspective view showing the overall configuration of the refrigeration evaporator 13, FIG. 5 is a cross-sectional view showing the cross-sectional shape of the flat tube 133, and FIG. 6 is a cross-sectional view showing the configuration inside the inlet-side header tank 134.

  As shown in FIG. 4, the refrigeration evaporator 13 of the present embodiment is connected to a plurality of flat tubes 133 through which refrigerant flows, and both ends of the flat tubes 133 in the longitudinal direction, and communicates with the flat tubes 133. An inlet-side header tank 134 and an outlet-side header tank 136 are provided. And this flat tube 133 is not normally provided with the outer fin joined to the outer surface of the flat tube 133, and while the outer peripheral surface whole area of the flat tube 133 is exposed to air, the cross-sectional shape is As shown in FIG. 5, the shape is symmetrical with respect to the center line CL connecting the leading edge to the trailing edge, and the leading edge portion and the trailing edge portion are formed with gentle curved surfaces, and the leading edge portion, the trailing edge portion, Are formed in an oblong flat shape that is connected linearly.

  Furthermore, the inside of the flat tube 133 is divided into a plurality of parts, and a plurality of refrigerant passages 133a are provided side by side from the front edge part to the rear edge part. In this embodiment, the aluminum material is extruded or drawn. By applying, the refrigerant passage 133a and the flat tube 133 are simultaneously formed.

  Reference numeral 131 shown in FIG. 4 denotes a core body 131 composed of a plurality of flat tubes 133, and the refrigerant flows out from the inlet header tank 134 in the horizontal direction into the core body 131. That is, the refrigeration evaporator 13 of this embodiment is installed in the cooling unit 130 in the horizontal direction. 4 is an inlet pipe through which the low-pressure gas-liquid two-phase refrigerant decompressed by the decompression means 12 flows into the inlet-side header tank 134, and 13b flows out the evaporated refrigerant to the accumulator 14. This is the outlet piping.

  By the way, the refrigeration evaporator 13 of the present embodiment is configured to improve the distribution of the refrigerant flowing into the plurality of flat tubes 133 from the inlet side header tank 134, and the main part of the present invention is shown in FIG. Based on As shown in FIG. 6, the inlet-side header tank 134 has a partition member 135 for blocking the refrigerant flowing from the inlet pipe 13 a between the outlet end of the inlet pipe 13 a and the inlet end of the flat tube 133. Is provided.

  That is, the gas-liquid two-phase refrigerant flowing from the inlet pipe 13 a is once blocked by the partition member 135, and then the liquid-phase refrigerant that has passed over the upper end of the partition member 135 reaches the inlet end of the flat tube 133. It comes to leak. This is because the refrigerant flowing in from the inlet pipe 13a is temporarily accumulated in this portion, so that the deviation of the refrigerant flow is prevented and the liquid-phase refrigerant flows out evenly at the inlet ends of the plurality of flat tubes 133. It can be done. In the present embodiment, the inlet pipe 13a is provided at a substantially central portion with respect to the longitudinal direction of the inlet-side header tank 134 and on the side facing the inlet end portion of the flat tube 133. Also good.

  Next, the electric control unit will be described. The control device 22 which is an electric control unit is configured to include computer means such as a microcomputer, and performs predetermined arithmetic processing programmed in advance on the basis of an input signal from an inlet terminal, so that the refrigeration unit The operation of the cycle device 5 and the blower 19 is controlled. Sensors, switches, and the like described below are connected to the input terminal of the control device 22.

  The internal temperature sensor 24 is a temperature sensor that detects the internal temperature in the freezer 2. The temperature setter 25 is for setting the internal set temperature in the freezer 2 by the manual operation of the occupant. For example, the internal set temperature can be arbitrarily adjusted in the range of −10 ° C. to −30 ° C. . The refrigeration operation switch 26 outputs a signal for operating and stopping the refrigeration cycle apparatus 5 by manual operation of the occupant, and the engine operation switch 27 outputs a signal corresponding to the operation and stop of the engine.

  A door switch 28 that is opened and closed in conjunction with opening and closing of the opening and closing doors 3 and 4 is installed at the peripheral edge of the opening 18 at the rear of the freezer 2. On the other hand, the electromagnetic clutch 7, the condensing fan 10, the freezing fan 17, the defrosting valve 16, the air curtain forming blower 19, and the like are connected to the output terminal of the control device 22.

  The operation of the refrigeration cycle apparatus 5 and the blower 19 configured as above will be described. First, when the vehicle travels, power is transmitted from the traveling engine 8 to the compressor 6 via the electromagnetic clutch 7 to operate the compressor 6, and the fans 10 and 17 are activated, and the refrigeration cycle apparatus 5 is operated. It becomes a state. The cold air cooled by the freezing evaporator 13 is blown out into the freezer 2 by the freezing fan 17 to cool the symmetrically preserved material in the freezer. At this time, the defrost valve 16 is closed, and the refrigerant does not flow into the bypass flow path 15.

  On the other hand, when stopping to carry in and out the symmetrically stored product in the warehouse, when the vehicle engine 8 is stopped, the compressor 6 is stopped along with the stop of the vehicle engine 8, and the cooling unit 130 in the warehouse is The freezing fan 17 is also stopped. When the open / close doors 3 and 4 at the rear of the freezer 2 are opened, the door switch 28 is turned on in conjunction with the opening. The blower motors 20e and 21e are energized by the control device 22, the cross flow fans 20 and 21 are operated, an air curtain is formed from the lower side to the upper side of the opening 18, and the high temperature outside air is stored in the freezer 2 To prevent intrusion.

  At this time, the defrost valve 16 is opened, and the refrigerant pressure difference (about 1.9 MPa) between the discharge side of the compressor 6 and the upstream portion of the refrigeration evaporator 13 causes the high pressure side (the compressor 6 (Upstream side of the condenser 9) of the high-temperature refrigerant flows into the refrigeration evaporator 13 via the bypass passage 15. When the high-temperature refrigerant flows into the refrigeration evaporator 13, the frost 37 frosted on the refrigeration evaporator 13 is melted into water and discharged to the outside. When the loading / unloading of the cargo is completed, the open / close doors 3 and 4 are closed, and the door switch is turned off, the defrost valve 16 is closed again, and the flow of the high-temperature refrigerant into the refrigeration evaporator 13 is stopped. The

  The air blown to the freezing evaporator 13 by the freezing fan 17 passes through the air passage formed between the flat tubes 133 and is cooled by exchanging heat with the refrigerant passing through the freezing evaporator 13. Is. By the way, since the refrigerant | coolant evaporator 13 which cools the air of this kind of freezer 2 is generally used in a freezing region where the internal temperature is 0 ° C. to 30 ° C., the flow rate of the refrigerant is relatively small. Has grasped the distribution performance through an experiment by visualization, and the method and result will be described with reference to FIG.

  FIG. 7 is a characteristic diagram summarizing the temperature distribution when the surface temperature distribution of the core main body 131 in the refrigeration evaporator 13 is visualized by the thermotracer when the partition member 135 is not provided in the inlet side header tank 134. is there. As shown in FIG. 7, when the partition member 135 is not provided, the surface temperature of the part surrounded by the alternate long and short dash line A shown in the drawing is higher than the other part.

  By the way, in the refrigeration evaporator 13 having the partition member 135 according to the present embodiment, the surface temperature distribution of the core body 131 was confirmed by the thermotracer in the same manner. The temperature distribution was shown, and it was confirmed that the flat tubes 133 were evenly distributed.

  Thus, when the partition member 135 is not provided, the inventors have obtained the inertial force and the central portion of the core body 131 into which the refrigerant flowing from the inlet pipe 13a flows directly from the outlet end of the inlet pipe 13a. Thus, it has been found that a low-temperature liquid-phase refrigerant flows biased to both ends of the core body 131 on the side where a large amount of refrigerant flows to both ends in the inlet-side header tank 134. Furthermore, it has been found that by providing the partition member 135, it is distributed evenly because it is once dammed up from the partition member 135 and then flows out to each flat tube 133.

  In the above embodiment, the connection between the inlet side header tank 134 and the inlet end portion of each flat tube 133 is as shown in FIG. 6, and the lower end of the inlet end portion of each flat tube 133 is the inlet side header tank. Although it is provided above the lower end in 134, specifically, as shown in FIG. 8, the lower end of the inlet end of each flat tube 133 is in contact with the lower end in the inlet-side header tank 134. It may be configured. According to this, the liquid phase refrigerant in the inlet side header tank 134 can be surely flowed out to the flat tube 133 side than in the present embodiment.

  According to the refrigeration evaporator 13 which is a heat exchanger according to the first embodiment described above, the refrigerant flowing from the inlet pipe 13a is once blocked in the inlet side header tank 134, and then a plurality of flat tubes. Since the partition member 135 that flows out to the inlet end portion of 133 is provided, it is possible to prevent the liquid-phase refrigerant distributed to the inlet end portions of the plurality of flat tubes 133 from being unevenly distributed. Thereby, the cooling performance of the freezing evaporator 13 can be improved.

  Further, the inlet ends of the plurality of flat tubes 133 are arranged in such a manner that their lower ends are in contact with the lower ends in the inlet header tank 134, so that the liquid-phase refrigerant in the inlet header tank 134 can be surely received. Can flow out into the flat tube 133.

(Second Embodiment)
In the present embodiment, specifically, as shown in FIGS. 9 and 10, a communication hole that communicates the outlet end portion of the inlet pipe 13 a and the inlet end portions of the plurality of flat tubes 133 in the longitudinal direction of the partition member 135. 135a is formed. That is, it is a hole for relieving that a large amount of refrigerant flowing from the inlet pipe 13a flows to both end sides in the inlet-side header tank 134 due to inertial force. According to this, the deviation of the refrigerant flow can be easily prevented. In the present embodiment, the four communication holes 135a are formed in the longitudinal direction of the inlet-side header tank 134, but the number is not limited to this.

(Third embodiment)
In the refrigeration evaporator 13 mounted on the refrigeration vehicle, when the vehicle is tilted, the refrigeration evaporator 13 installed in the horizontal direction is also tilted. That is, when the refrigeration evaporator 13 is inclined in the longitudinal direction of the inlet-side header tank 134, the upper end of the partition member 134 is inclined with respect to the liquid phase surface of the refrigerant, so that the distribution performance is deteriorated.

  Therefore, in this embodiment, the upper end of the partition member 135 is configured to maintain the horizontal direction even when the inlet-side header tank 134 is inclined in the longitudinal direction. Specifically, as shown in FIG. 11 and FIG. 12, a Yajirobe type float member 135a having a support member 135b at the center and weight members 135c at both ends thereof is formed, and the partition member 135 is formed by the support member 135b. It is configured to be integrated. The upper end of the float member 135a can be maintained in the horizontal direction by weight members 135c provided on the left and right of the support member 135b.

  According to this, although the liquid phase surface in the inlet side header tank 134 may be inclined due to the inclination of the vehicle, the upper end of the partition member 135 is maintained in the horizontal direction so as to respond to the liquid phase surface. It is possible to prevent the liquid refrigerant from being distributed to the inlet end of the flat tube 133. Therefore, the distribution performance can be improved more than the above embodiment.

(Other embodiments)
In the above embodiment, the heat exchanger of the present invention is applied to the refrigeration cycle apparatus 5 mounted on the refrigerator 1. However, the present invention is not limited to this, and the present invention may be applied to a stationary freezer such as a warehouse. good. Further, the cross-sectional shape of the flat tube 133 is not limited to the above-described shape, and may be, for example, an elliptical shape or a streamline shape.

  In the above embodiment, the present invention is applied to the refrigeration evaporator 13 using latent heat of vaporization. However, the present invention is not limited to this, and a heat exchanger that cools air with sensible heat. Is also applicable.

It is a perspective view which shows the structure of the freezer truck 1 to which this invention is applied. It is a schematic diagram which shows the refrigerating cycle of the freezer truck 1 shown in FIG. It is a perspective view which shows the structure of the door part of the refrigerator truck 1 shown in FIG. It is a perspective view which shows the whole structure of the freezing evaporator 13 in 1st Embodiment of this invention. It is sectional drawing which shows the cross-sectional shape of the flat tube 133 in 1st Embodiment of this invention. It is sectional drawing which shows the structure in the inlet side header tank 134 in 1st Embodiment of this invention. It is a characteristic view which shows surface temperature distribution of the evaporator 13 for freezing when the partition member 135 is not provided. It is sectional drawing which shows the structure in the inlet side header tank 134 in the modification of 1st Embodiment of this invention. It is a perspective view which shows the whole structure of the freezing evaporator 13 in 2nd Embodiment of this invention. It is sectional drawing which shows the structure in the inlet side header tank 134 in 2nd Embodiment of this invention. It is sectional drawing which shows the structure in the inlet side header tank 134 in 3rd Embodiment of this invention. It is BB sectional drawing shown in FIG.

Explanation of symbols

13a ... Inlet piping 133 ... Flat tube 134 ... Inlet side header tank 135 ... Partition member 135a ... Communication hole 136 ... Outlet side header tank

Claims (4)

A plurality of flat tubes (133) in which the refrigerant flows in the horizontal direction;
An inlet-side header tank (134) in which inlet ends of the plurality of flat tubes (133) are arranged in the longitudinal direction;
In the heat exchanger horizontally provided with outlet side header tanks (136) arranged in the longitudinal direction at the outlet ends of the plurality of flat tubes (133),
The inlet header tank (134) includes an inlet pipe (13a) into which a refrigerant flows, an outlet end of the inlet pipe (13a), and inlet ends of the plurality of flat tubes (133). A partition member (135) for blocking the refrigerant flowing in from the inlet pipe (13a) , and the refrigerant flowing in from the inlet pipe (13a ) is once blocked by the partition member (135) ; A heat exchanger configured to flow out to an inlet end portion of the plurality of flat tubes (133). The partition member (135) is configured such that the upper end of the partition member (135) maintains a horizontal direction when the inlet-side header tank (134) is inclined with respect to the longitudinal direction thereof. The heat exchanger according to claim 1, wherein The partition member (135 ) is provided with a communication hole (135a) that communicates the outlet end of the inlet pipe (13a) and the inlet ends of the plurality of flat tubes (133) in the longitudinal direction. The heat exchanger according to claim 1 . Inlet end of said plurality of flat tubes (133) is the preceding claims, characterized in that it is arrayed so that its lower end is in contact with the lower end of the inlet side header tank (134) in The heat exchanger according to any one of 3 .

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