Drum type ice-making machine

Abstract

To provide a drum type ice-making machine capable of preventing occurrence of failure due to a temperature of a high-temperature high-pressure liquefied refrigerant.SOLUTION: A drum type ice-making machine includes: a first refrigerant circuit 32 into which a liquefied refrigerant condensed by a condenser CD flows; an expansion valve EV provided in the first refrigerant circuit 32 and decompressing the liquefied refrigerant; a second refrigerant circuit 33 into which a vaporized refrigerant vaporized in an ice-making drum 12 flows; a heat exchange section 34 for exchanging heat between the liquefied refrigerant and the vaporized refrigerant; and temperature detection means 47 capable of detecting the temperature of the refrigerant. The first refrigerant circuit 32 is branched into a first branch circuit 41 and a second branch circuit 42. The first branch circuit 42 includes a first solenoid valve 44 and the heat exchange section 34, and the second branch circuit 42 includes a second solenoid valve 46. On the basis of the detection temperature obtained by the temperature detection means 47, opening / closing of the first solenoid valve 44 and the second solenoid valve 46 is switched.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] This invention relates to a drum-type ice maker in which an ice-making drum is partially immersed in ice-making water stored in an ice-making water tank and rotated, and ice formed on the outer surface of the ice-making drum is peeled off with a cutter to obtain ice pieces. [Background technology]

[0002] As an automatic ice making machine, a drum type ice making machine is known in which a cylindrical ice making drum cooled by a refrigerant is rotated in an ice making water tank in which ice making water is stored, forming layers of ice on the surface of the ice making drum, and the formed ice is peeled off by a cutter to continuously make ice pieces (see, for example, Patent Document 1). The drum type ice making machine of Patent Document 1 includes an ice making water tank that stores a predetermined amount of ice making water, and an ice making drum that is arranged inside the ice making water tank and is rotatable about a horizontal axis with a part of it immersed in the ice making water. It also includes a cutter that scrapes off the ice formed on the outer surface of the ice making drum. The cutter is provided along the axial direction of the ice making drum with its blade pointing toward the outer surface of the part of the ice making drum that is exposed from the ice making water. The ice pieces scraped off by the cutter are then discharged into an ice storage room via a chute.

[0003] The applicant has also found that the cooling efficiency can be improved by configuring the refrigeration circuit for cooling the ice making drum in the drum type ice making machine as shown in Fig. 7. Specifically, in the refrigeration circuit 21, the compressor CM is connected to the condenser CD via the discharge pipe 31, and the refrigerant pipe 32 leading out from the condenser CD is connected to the inlet 28c of the refrigerant inlet / outlet part 28b of the ice making drum 12 via the expansion valve EV. Also, the suction pipe 33 connected to the outlet 28d of the refrigerant inlet / outlet part 28b is connected to the suction side of the compressor CM. That is, during ice making operation, the vaporized refrigerant compressed by the compressor CM is liquefied in the condenser CD, then decompressed by the expansion valve EV, and heat exchange is performed in the process of evaporation in the ice making drum 12 as an evaporator, thereby cooling the ice making drum 12 to below freezing point. The vaporized refrigerant evaporated in the ice making drum 12 returns to the compressor CM via the suction pipe 33. In addition, the refrigeration circuit 21 is provided with a heat exchange section 34 that brings the refrigerant piping 32 between the condenser CD and the expansion valve EV and the suction pipe 33 into close proximity, and is configured to exchange heat between the high-temperature, high-pressure liquefied refrigerant flowing out of the condenser CD and flowing through the refrigerant piping 32 in the heat exchange section 34 and the low-temperature, low-pressure vaporized refrigerant flowing out of the ice making drum 12 and flowing through the suction pipe 33. By exchanging heat between the high-temperature, high-pressure liquefied refrigerant and the low-temperature, low-pressure vaporized refrigerant, the cooling efficiency of the refrigeration circuit 21 is improved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5329384 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in the above-mentioned refrigeration circuit 21, a situation may occur in which the temperature of the high-temperature, high-pressure liquefied refrigerant flowing out of the condenser CD and flowing through the refrigerant pipe 32 becomes low, depending on the installation environment and operating conditions of the drum ice maker. When the temperature of the high-temperature, high-pressure liquefied refrigerant becomes low, the temperature of the liquefied refrigerant is further reduced by heat exchange with the low-temperature, low-pressure vaporized refrigerant in the heat exchange section 34. Here, if the temperature of the liquefied refrigerant becomes too low, the refrigerant temperature will be reduced to 0°C or lower when it is decompressed by the expansion valve EV and passes through the rotating shaft (medium inlet / outlet section 28b) of the ice making drum 12, and there is a concern that the rotating shaft may freeze or that the bearings, oil seals, refrigerant seals, etc. provided on the rotating shaft may be damaged.

[0006] Therefore, in consideration of the above-mentioned problems inherent in the conventional technology, the present invention has been proposed to preferably solve these problems, and has an object to provide a drum type ice maker that can prevent malfunctions caused by the temperature of the high-temperature, high-pressure liquefied refrigerant. [Means for solving the problem]

[0007] In order to overcome the above problems and achieve the intended purpose, the first means is: A drum-type ice making machine includes an ice making drum (12) that rotates while being partially immersed in ice making water stored in an ice making water tank (11), and a cutter (23) that scrapes off ice formed on the outer surface of the ice making drum (12), a first refrigerant circuit (32) through which a liquefied refrigerant condensed in a condenser (CD) flows toward the ice making drum (12); an expansion valve (EV) provided in the first refrigerant circuit (32) to reduce the pressure of a liquefied refrigerant; a second refrigerant circuit (33) through which the vaporized refrigerant vaporized in the ice making drum (12) flows toward a compressor; a heat exchange section (34) for exchanging heat between a liquefied refrigerant flowing through the first refrigerant circuit (32) and a vaporized refrigerant flowing through the second refrigerant circuit (33); and a temperature detection means (47) capable of detecting a refrigerant temperature during a period in which the liquefied refrigerant condensed in the condenser (CD) reaches the ice making drum (12), the first refrigerant circuit (32) is configured to branch into a first branch circuit (41) and a second branch circuit (42) in a path extending from the condenser (CD) to the expansion valve (EV); the first branch circuit (42) is provided with a first flow path switching means (44) which opens and closes the first branch circuit (42) and is also provided with the heat exchange unit (34); the second branch circuit (42) is provided with a second flow path switching means (46) which opens and closes the second branch circuit (42); The first flow path switching means (44) and the second flow path switching means (46) are switched between open and closed states based on the temperature detected by the temperature detection means (47). According to this configuration, the temperature of the high-temperature, high-pressure liquefied refrigerant liquefied in the condenser is detected by the temperature detection means, and the first flow path switching means and the second flow path switching means are switched on and off based on the detected temperature, thereby switching whether or not the liquefied refrigerant passes through the heat exchange unit. Therefore, when the liquefied refrigerant is at a low temperature, it is possible to prevent the temperature from being further decreased by heat exchange with the vaporized refrigerant in the heat exchange unit, and to prevent problems such as damage to bearings, oil seals, refrigerant seals, etc. provided on the rotating shaft. In addition, when the liquefied refrigerant is at a high temperature, the cooling efficiency of the refrigeration circuit can be improved by exchanging heat between the liquefied refrigerant and the vaporized refrigerant in the heat exchange unit.

[0008] The second method is The present invention is characterized in that the temperature detection means (47) is configured to detect the temperature of the liquefied refrigerant flowing on the condenser (CD) side of a branching position where the first branch circuit (41) and the second branch circuit (42) branch off in the first refrigerant circuit (32). According to this configuration, the temperature of the liquefied high-temperature, high-pressure liquefied refrigerant can be detected more stably, and the path can be switched with high accuracy.

[0009] The third method is The present invention is configured such that, after the first flow path switching means (44) and the second flow path switching means (46) are switched between open and closed, the first flow path switching means (44) and the second flow path switching means (46) are maintained in an open or closed state until a predetermined waiting time (TM1) has elapsed, and, after the waiting time (TM1) has elapsed, the first flow path switching means (44) and the second flow path switching means (46) are switched between open and closed based on the temperature detected by the temperature detection means (47). According to this configuration, the switching of the path through which the liquefied refrigerant flows can be suspended until a predetermined waiting time has elapsed, thereby preventing the path through which the liquefied refrigerant flows from being switched based on an unstable detection temperature by the temperature detection means, and enabling highly accurate switching of the path based on temperature detection by the temperature detection means. Effect of the Invention

[0010] According to the drum type ice making machine of the present invention, it is possible to prevent malfunctions from occurring even in a situation where the temperature of the high-temperature, high-pressure liquefied refrigerant drops. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic vertical sectional front view showing a drum type ice making machine according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing a first example of a refrigeration circuit. [Diagram 3] FIG. 4 is a schematic diagram showing a refrigeration circuit of a second example. [Figure 4] FIG. 11 is a schematic diagram showing a refrigeration circuit of a third example. [Diagram 5] FIG. 4 is a flowchart of a switching control process in the first embodiment. [Figure 6] FIG. 11 is a flowchart of a switching control process in the second embodiment. [Figure 7] FIG. 2 is a schematic diagram showing a refrigeration circuit of a drum type ice maker. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, a drum type ice maker according to the present invention will be described below with reference to the accompanying drawings, showing preferred embodiments. In the following description, "upper", "lower", "left" and "right" refer to FIG. 1 as a reference.

[0013] (Embodiment 1) As shown in Fig. 1, a drum type ice maker 10 of the first embodiment includes an ice making water tank 11 in which ice making water is stored, and a cylindrical ice making drum 12 arranged inside the ice making water tank 11 so as to be rotatable about a horizontal axis with a portion of the drum 12 immersed in the ice making water. The ice making water tank 11 is formed in a box shape with an open top by front, rear, left and right walls (front wall 13, rear wall 14, left wall 15, right wall 16) and a bottom wall 17, and the top opening is covered by a lid member 18 that can be opened and closed. A water supply port 19 that is connected to a water supply pipe (not shown) leading from an external water system is provided on the rear wall 14 of the ice making water tank 11, and ice making water (tap water) is supplied from the water supply port 19 to the inside of the ice making water tank 11 via the water supply pipe. In addition, a water level sensor 20 such as a float switch for detecting the amount of ice-making water stored (water level) is arranged inside the ice-making water tank 11, and the water level in the ice-making water tank 11 is maintained constant by controlling the amount of ice-making water supplied according to the water level detection status by the sensor 20.

[0014] Drum type ice maker 10 is equipped with a control means (not shown) that controls devices such as compressor CM and valves such as water supply valves that constitute refrigeration circuit 21 described later, and other devices. Drum type ice maker 10 is configured such that each device is controlled by the control means, and during ice making operation, refrigerant is supplied from refrigeration circuit 21 to the inside of ice making drum 12, and ice making drum 12 cooled by the refrigerant rotates in ice making water tank 11 to grow layered ice (ice layer I) on its surface (outer surface). In the embodiment, drum type ice maker 10 starts ice making operation by turning on an operation switch (not shown) connected to the control means, and stops ice making operation by turning off the operation switch. In addition, when ice making operation is stopped, a drain valve (not shown) connected to ice making water tank 11 is opened to drain the ice making water stored in ice making water tank 11.

[0015] As shown in Fig. 1, a cutter 23 is disposed on the right wall 16 of the ice making water tank 11 via a cutter mount 22. The cutter 23 is disposed with its cutting edge 23a close to the outer surface of the ice making drum 12 and inclined downward as it moves away from the ice making water tank 11. The upper surface of the cutter 23 forms a flat slope 25 that slopes downward as it moves away from the ice making water tank 11, and the lower end of the slope 25 faces the receiving port 24a of the chute 24 that communicates with an ice storage bin (not shown). That is, the cutter 23 is configured to scrape off the ice layer I formed on the outer surface of the ice making drum 12 with the cutting edge 23a of the cutter 23, slide the scraped ice pieces down the slope 25 of the cutter 23, and release the ice pieces from the receiving port 24a to the chute 24. The ice pieces discharged into the chute 24 fall down the inside of the chute 24 and are discharged into the ice storage bin, where they are stored.

[0016] As shown in Figs. 2 to 4, the ice making drum 12 has rotating shafts 28a and 28b extending outward from the center of each end face in the axial direction, and each rotating shaft 28a and 28b is rotatably supported by shaft supports provided on the front and rear walls 13 and 14 of the ice making water tank 11. One rotating shaft 28a is connected to a driving means (not shown), and is configured to rotate the ice making drum 12 by the driving means during ice making operation. The other rotating shaft 28b is configured as a double pipe that forms an inlet 28c and an outlet 28d of a refrigerant flow path formed inside the ice making drum 12, and is configured to guide the refrigerant from the refrigeration circuit 21 into the inside of the ice making drum 12 through the rotating shaft 28b, and to return the refrigerant that has exchanged heat with the ice making drum 12 to the refrigeration circuit 21. That is, the ice making drum 12 functions as an evaporator that constitutes the refrigeration circuit 21, and the double-pipe rotating shaft 28b functions as a refrigerant inlet and outlet portion.

[0017] As shown in Figs. 2 to 4, the refrigeration circuit 21 is configured such that the compressor CM is connected to the condenser CD via a discharge pipe 31, and the refrigerant pipe 32 forming the first refrigerant circuit leading out from the condenser CD is connected to the inlet 28c of the rotating shaft 28b of the ice making drum 12 via an expansion valve EV. Also, a suction pipe 33 forming the second refrigerant circuit connecting to the outlet 28d of the rotating shaft 28b is connected to the suction side of the compressor CM. That is, during ice making operation, the vaporized refrigerant compressed by the compressor CM is liquefied in the condenser CD, then decompressed by the expansion valve EV, and heat exchange is performed in the process of evaporation in the ice making drum 12 as an evaporator, thereby cooling the ice making drum 12 to below freezing point. The vaporized refrigerant evaporated in the ice making drum 12 is returned to the compressor CM via the suction pipe 33. A temperature sensing tube 35 is provided near the connection portion of the suction pipe 33 to the rotary shaft 28b, and the opening degree of the expansion valve EV is controlled according to the temperature of the refrigerant flowing through the suction pipe 33 detected by the temperature sensing tube 35.

[0018] Here, the refrigerant pipe 32 is configured to branch into a first branch pipe 41 as a first branch circuit and a second branch pipe 42 as a second branch circuit in a path from the condenser CD to the expansion valve EV. The first branch pipe 41 and the second branch pipe 42 are adapted to merge before reaching the expansion valve EV, and the liquefied refrigerant condensed in the condenser CD passes through either the first branch pipe 41 or the second branch pipe 42 to reach the expansion valve EV.

[0019] Further, the refrigeration circuit 21 is provided with a heat exchange section 34 in which the first branch pipe 41 and the suction pipe 33 are adjacent to each other, and the heat exchange section 34 is configured to exchange heat between the high-temperature, high-pressure liquefied refrigerant flowing out of the condenser CD and flowing through the first branch pipe 41 and the low-temperature, low-pressure vaporized refrigerant flowing out of the ice making drum 12 and flowing through the suction pipe 33. That is, the liquefied refrigerant condensed in the condenser CD and passing through the first branch pipe 41 exchanges heat with the vaporized refrigerant in the heat exchange section 34, while the liquefied refrigerant passing through the second branch pipe 42 reaches the expansion valve EV without exchanging heat with the vaporized refrigerant.

[0020] 2 to 4, the first branch pipe 41 is provided with a first solenoid valve 44 as a flow path switching means, and opening and closing the first solenoid valve 44 allows switching between a state in which the liquefied refrigerant can flow through the first branch pipe 41 and a state in which the flow of the liquefied refrigerant is blocked. Similarly, the second branch pipe 42 is provided with a second solenoid valve 46 as a flow path switching means, and opening and closing the second solenoid valve 46 allows switching between a state in which the liquefied refrigerant can flow through the second branch pipe 42 and a state in which the flow of the liquefied refrigerant is blocked.

[0021] In addition, the refrigeration circuit 21 is provided with a temperature detection means 47 for detecting the temperature of the refrigerant flowing through the refrigerant path from the condenser CD to the refrigerant inlet 28c of the ice making drum 12. The temperature detection means 47 is electrically connected to the control means, and the control means is configured to perform a switching control process for switching the open / closed states of the first solenoid valve 44 and the second solenoid valve 46 according to the detected temperature T by the temperature detection means 47. That is, according to the temperature of the high-temperature, high-pressure liquefied refrigerant sent from the condenser CD, the path can be switched between a path (first path) that passes through the first branch pipe 41 to the expansion valve EV via the heat exchanger 34 and the expansion valve EV, and a path (second path) that passes through the second branch pipe 42 to the expansion valve EV without passing through the heat exchanger 34. The temperature detection means 47 can be a conventionally known means such as a thermistor or a thermocouple.

[0022] 2, the temperature detection means 47 can be disposed upstream of the branching position where the first branch pipe 41 and the second branch pipe 42 branch off in the refrigerant pipe 32. That is, in this arrangement example, the temperature detection means 47 detects the temperature of the liquefied refrigerant before heat exchange between the high-temperature, high-pressure liquefied refrigerant liquefied in the condenser CD and the vaporized refrigerant in the heat exchange section 34, and the route through which the liquefied refrigerant flows can be switched.

[0023] 3, the temperature detection means 47 can be disposed downstream (on the expansion valve EV side) of the joining position where the first branch pipe 41 and the second branch pipe 42 join in the refrigerant pipe 32. That is, in this arrangement example, the temperature detection means 47 detects the temperature of the liquefied refrigerant after heat exchange between the high-temperature, high-pressure liquefied refrigerant liquefied in the condenser CD and the vaporized refrigerant in the heat exchange section 34, and the path through which the liquefied refrigerant flows can be switched.

[0024] 4, as a third example of the position of the temperature detection means 47, the temperature detection means 47 can be disposed downstream of the expansion valve EV in the refrigerant pipe 32 (the side of the refrigerant inlet 28c in the ice making drum 12). That is, in this example of the arrangement, the temperature detection means 47 detects the temperature of the liquefied refrigerant just before it is reduced in pressure by the expansion valve EV and reaches the refrigerant inlet 28c in the ice making drum 12, and the route through which the liquefied refrigerant flows can be switched.

[0025] 5, in the switching control process executed by the control means, it is determined whether the detected temperature T detected by the temperature detection means 47 is equal to or higher than a predetermined switching temperature (S10). If the detected temperature T is equal to or higher than the switching temperature, it is determined whether the first solenoid valve 44 is open (S12), and if the first solenoid valve 44 is not open, the first solenoid valve 44 is opened and the second solenoid valve 46 is shut off so that the high-temperature, high-pressure liquefied refrigerant flows through a path (first path) that passes through the first branch pipe 41, via the heat exchange unit 34, and reaches the expansion valve EV without passing through the second branch pipe 42 (S14). Then, when the detected temperature T detected by the temperature detection means 47 is less than the switching temperature, it is determined whether or not the second solenoid valve 46 is open (S16), and when the second solenoid valve 46 is not open, the first solenoid valve 44 is shut off and the second solenoid valve 46 is opened so that the high-temperature, high-pressure liquefied refrigerant flows through a path (second path) leading to the expansion valve EV through the second branch pipe 42 without passing through the heat exchange section 34 (S18). Here, the switching temperature can be appropriately set depending on the installation environment of the drum type ice making machine 10, and may be, for example, 10°C in the first example, 5°C in the second example, or 1°C in the third example.

[0026] In this way, the temperature of the high-temperature, high-pressure liquefied refrigerant liquefied in the condenser CD is detected by the temperature detection means 47, and the open / closed states of the first solenoid valve 44 and the second solenoid valve 46 are switched based on the detected temperature T, so that it is possible to switch between a state in which the liquefied refrigerant flows through the first branch pipe 41 leading to the expansion valve EV via the heat exchange unit 34 and a state in which the liquefied refrigerant flows through the second branch pipe 42 leading to the expansion valve EV without passing through the heat exchange unit 34. Therefore, when the liquefied refrigerant is at a low temperature below the switching temperature, the liquefied refrigerant flows through the second branch pipe 42, which prevents the temperature of the liquefied refrigerant from being further reduced by heat exchange with the vaporized refrigerant in the heat exchange unit 34, and prevents problems such as damage to bearings, oil seals, and refrigerant seals provided on the rotating shaft 28b that has been depressurized and vaporized in the expansion valve EV. In addition, when the temperature of the liquefied refrigerant is higher than the switching temperature, the liquefied refrigerant flows through the first branch pipe 41, and heat is exchanged between the liquefied refrigerant and the vaporized refrigerant in the heat exchange section 34, thereby improving the cooling efficiency of the refrigeration circuit 21.

[0027] Here, as in the first example shown in Fig. 2, by providing the temperature detection means 47 upstream of the branching position where the first branch pipe 41 and the second branch pipe 42 branch off, the temperature of the liquefied high-temperature and high-pressure liquefied refrigerant can be detected more stably, and the path can be switched with high accuracy. For example, as in the second example shown in Fig. 3, when the temperature detection means 47 is provided downstream (on the expansion valve EV side) of the joining position where the first branch pipe 41 and the second branch pipe 42 join, there is a possibility that the liquefied refrigerant may remain in the pipes 41 and 42 between the first solenoid valve 44 or the second solenoid valve 46 and the expansion valve EV, and the temperature detection by the temperature detection means 47 tends to become unstable due to the movement of the remaining liquefied refrigerant. In contrast, the arrangement of the first example is more preferable because the detected temperature T by the temperature detection means 47 is not affected by the remaining liquefied refrigerant, and more stable temperature detection is possible. 4, when temperature detection means 47 is provided downstream (on the expansion valve EV side) of the joining position where first branch pipe 41 and second branch pipe 42 join, when temperature detection means 47 is provided downstream of expansion valve EV (on the refrigerant inlet portion 28c side of ice making drum 12), the liquefied refrigerant is decompressed by expansion valve EV and the refrigerant temperature is lowered. Therefore, a slight error in temperature detection by temperature detection means 47 may cause rotating shaft 28b to freeze or damage bearings, oil seals, refrigerant seals, etc. provided on rotating shaft 28b, so high accuracy is required for temperature detection by temperature detection means 47, and there is a concern that switching of a highly accurate path may become difficult or that using a highly accurate temperature detection means 47 may increase costs. On the other hand, in the arrangements of the first and second examples, the temperature can be detected by the temperature detection means 47 before the pressure is reduced by the expansion valve EV, which has the advantage that the temperature detection by the temperature detection means 47 can be made flexible, and highly accurate path switching can be achieved based on the temperature detection by the temperature detection means 47 while keeping costs low.

[0028] 5, when the open / closed states of the first solenoid valve 44 and the second solenoid valve 46 are switched based on the detected temperature T of the temperature detection means 47, the control means maintains the open / closed states of the first solenoid valve 44 and the second solenoid valve 46 until a predetermined waiting time TM1 has elapsed since the open / closed states are switched, and switches the open / closed states of the first solenoid valve 44 and the second solenoid valve 46 based on the detected temperature T of the temperature detection means 47 after the waiting time TM1 has elapsed (S20). That is, when the open / closed states of the first solenoid valve 44 and the second solenoid valve 46 are switched, the execution of the switching control process is suspended until the waiting time TM1 has elapsed, and the execution of the switching control process is resumed when the waiting time TM1 has elapsed.

[0029] That is, when the opening and closing states of the first solenoid valve 44 and the second solenoid valve 46 are switched, there is a possibility that liquefied refrigerant may remain in the pipes 41 and 42 between the first solenoid valve 44 or the second solenoid valve 46 and the expansion valve EV, and therefore the temperature detected by the temperature detection means 47 is likely to fluctuate while the remaining liquefied refrigerant is flowing. In addition, there is a concern that the simultaneous switching of the opening and closing states of the first solenoid valve 44 and the second solenoid valve 46 may cause a sudden change in the path through which the high-temperature and high-pressure liquefied refrigerant flows, which may cause the temperature detected by the temperature detection means 47 to become unstable. For this reason, when the opening and closing states of the first solenoid valve 44 and the second solenoid valve 46 are switched, the execution of the switching control process is suspended until a predetermined waiting time TM1 has elapsed since the opening and closing states are switched, thereby preventing the opening and closing states of the first solenoid valve 44 and the second solenoid valve 46 from being switched based on unstable temperature detection, and there is an advantage that highly accurate path switching can be realized based on the temperature detection of the temperature detection means 47. Here, the length of the waiting time TM1 can be appropriately set according to the time it takes for the temperature detected by the temperature detection means 47 to stabilize after the path is switched, and can be set to, for example, 60 seconds.

[0030] (Embodiment 2) Next, a drum type ice maker 10 of embodiment 2 will be described. The configuration of drum type ice maker 10 of embodiment 2 has a common configuration with embodiment 1 described above, but the switching control process to be executed is partially different. That is, in embodiment 1, the switching control process is suspended until a predetermined waiting time TM1 has elapsed after switching the path, thereby stabilizing the temperature detection by temperature detection means 47, but in embodiment 2, when switching the open / closed state of first solenoid valve 44 and second solenoid valve 46 based on the detected temperature T of temperature detection means 47, first solenoid valve 44 and second solenoid valve 46 are opened until a predetermined waiting time TM2 has elapsed, and the open / closed state of first solenoid valve 44 and second solenoid valve 46 is switched after the waiting time TM2 has elapsed.

[0031] Specifically, in the switching control process in drum type ice making machine 10 of embodiment 2, as shown in Fig. 6, it is determined whether or not detected temperature T detected by temperature detection means 47 is equal to or higher than a predetermined switching temperature (S10). If it is equal to or higher than the switching temperature, it is determined whether or not first solenoid valve 44 is open (S12), and if first solenoid valve 44 is not open, first solenoid valve 44 and second solenoid valve 46 are opened (S30). At this time, first solenoid valve 44 and second solenoid valve 46 are maintained in the open state until a predetermined waiting time TM2 has elapsed since the open / closed state was switched, and high-temperature, high-pressure liquefied refrigerant is allowed to flow through each of a path (first path) that passes through first branch pipe 41 and heat exchanger 34 to expansion valve EV without passing through second branch pipe 42, and a path (second path) that passes through second branch pipe 42 to expansion valve EV without passing through heat exchanger 34 (S32). Then, after a predetermined waiting time TM2 has elapsed since switching the open / closed state, only the second solenoid valve 46 is shut off so that the high-temperature, high-pressure liquefied refrigerant flows through a path (first path) that passes through the first branch pipe 41, via the heat exchange section 34, and to the expansion valve EV without passing through the second branch pipe 42 (S34).

[0032] Moreover, when the detected temperature T detected by the temperature detection means 47 is lower than the switching temperature, it is determined whether the second solenoid valve 46 is open (S16), and when the second solenoid valve 46 is not open, the first solenoid valve 44 and the second solenoid valve 46 are opened in the same manner (S36). At this time, the first solenoid valve 44 and the second solenoid valve 46 are maintained in the open state until a predetermined waiting time TM2 has elapsed since the open / closed state was switched, and the high-temperature, high-pressure liquefied refrigerant is allowed to flow through each of the path (first path) that passes through the first branch pipe 41 and the heat exchange unit 34 to the expansion valve EV without passing through the second branch pipe 42, and the path (second path) that passes through the second branch pipe 42 to the expansion valve EV without passing through the heat exchange unit 34 (S38). Then, after a predetermined waiting time TM2 has elapsed since switching the open / closed state, only the first solenoid valve 44 is shut off, and the high-temperature, high-pressure liquefied refrigerant is controlled to flow through a path (second path) that passes through the second branch pipe 42 to the expansion valve EV without passing through the heat exchange section 34 (S40).

[0033] That is, as described above, when the opening and closing states of the first solenoid valve 44 and the second solenoid valve 46 are switched simultaneously, the temperature detected by the temperature detection means 47 is likely to fluctuate due to the sudden change in the path through which the high-temperature and high-pressure liquefied refrigerant flows. Therefore, when the opening and closing states of the first solenoid valve 44 and the second solenoid valve 46 are switched based on the detected temperature T of the temperature detection means 47, the first solenoid valve 44 and the second solenoid valve 46 are opened until a predetermined waiting time TM2 has elapsed since the opening and closing states were switched, thereby suppressing the temperature change detected by the temperature detection means 47, and it is possible to prevent the opening and closing states of the first solenoid valve 44 and the second solenoid valve 46 from being switched based on unstable temperature detection, and there is an advantage that highly accurate path switching can be realized based on the temperature detection of the temperature detection means 47. Here, the length of the waiting time TM2 in the second embodiment can be appropriately set according to the time it takes for the temperature detected by the temperature detection means 47 to stabilize, and can be set to, for example, 60 seconds.

[0034] The present application is not limited to the configurations of the above-described embodiments, and other configurations can be adopted as appropriate, and various embodiments can be adopted within the scope of the gist of the present invention. [Explanation of symbols]

[0035] 11 ice making water tank, 12 ice making drum, 23 cutter, 32 first refrigerant circuit 33 second refrigerant circuit, 34 heat exchange section, 41 first branch circuit, 42 second branch circuit 44: first solenoid valve (first flow path switching means), 46: second solenoid valve (second flow path switching means) 47 Temperature detection means, CD Condenser, EV Expansion valve

Claims

1. In a drum-type ice making machine, an ice making drum is rotated while being partially immersed in ice making water stored in an ice making water tank, and a cutter is provided to scrape off ice formed on the outer surface of the ice making drum. A first refrigerant circuit through which the liquefied refrigerant condensed in the condenser flows toward the ice making drum; an expansion valve provided in the first refrigerant circuit to reduce the pressure of a liquefied refrigerant; A second refrigerant circuit through which the vaporized refrigerant vaporized in the ice making drum flows toward a compressor; a heat exchange unit that exchanges heat between a liquefied refrigerant flowing through the first refrigerant circuit and a vaporized refrigerant flowing through the second refrigerant circuit; A temperature detection means is provided for detecting the temperature of the refrigerant condensed in the condenser until the liquefied refrigerant reaches the ice making drum, the first refrigerant circuit is configured to branch into a first branch circuit and a second branch circuit in a path from the condenser to the expansion valve, the first branch circuit is provided with a first flow path switching means for opening and closing the first branch circuit and is also provided with the heat exchanger, the second branch circuit is provided with a second flow path switching means for opening and closing the second branch circuit, The first flow path switching means and the second flow path switching means are configured to switch between open and closed states based on the temperature detected by the temperature detection means. The drum type ice maker is characterized by the following:

2. 2. The drum type ice making machine according to claim 1, wherein the temperature detection means is configured to detect a temperature of the liquefied refrigerant flowing on the condenser side of a branching position where the first branch circuit and the second branch circuit branch off in the first refrigerant circuit.

3. 3. The drum type ice maker of claim 1 or 2, wherein after the first flow path switching means and the second flow path switching means are switched between open and closed, the first flow path switching means and the second flow path switching means are maintained in an open and closed state until a predetermined waiting time has elapsed, and after the waiting time has elapsed, the first flow path switching means and the second flow path switching means are switched between open and closed based on the temperature detected by the temperature detection means.

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