Auger type ice maker

Abstract

To provide an auger type ice maker capable of making high-quality compressed ice by properly compressing flake-like ice without breaking a second stationary blade of which the compression head is thin.SOLUTION: In a compression head 18, a thick blade 20 and a thin blade 22 protruding from a cylindrical main body 18a facing the inside of a refrigeration casing in a radial direction are provided alternately while being separated in a circumferential direction. A compression passage 24 which is compressed by passing flake-like ice moved by an auger screw is formed between the blades which are adjacent to each other in the circumferential direction. On both side faces of the thick blade 20 in the circumferential direction, there are formed a first thick blade inclined plane 20a, which is inclined closer to the compression passage from a lower end toward an upper side, and a second thick blade inclined plane 20b which is connected to the upper end P of the first thick blade inclined plane 20a and inclined closer to the compression passage toward the upper side. The lower end portion D of the thin blade 22 is positioned correspondingly to the upper end P of the first thick blade inclined plane 20a in the thick blade 20.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This invention relates to an auger type ice making machine in which ice frozen on the inner wall surface of a freezer casing is scraped off with an auger screw while being transported upward, and the resulting ice flakes are compressed to produce compressed ice of a specified size. [Background technology]

[0002] There is known an automatic ice-making machine that includes an auger screw for shaving ice rotatably installed in a cylindrical freezer casing, and a compression head that is attached inside the upper end of the freezer casing and into which the upper end rotating shaft of the auger screw is rotatably fitted, and that rotates the auger screw during ice-making operation to shave off thin ice frozen on the inner wall surface of the freezer casing, transports the resulting ice flakes toward a compression passage of the compression head, and forms compressed ice having a cross section that approximates the cross section of the compression passage (see, for example, Patent Document 1). The compression head in the auger ice-making machine of Patent Document 1 has thick blades with a large circumferential thickness and thin blades with a small thickness that extend a predetermined length in the vertical direction on the outer circumferential surface of a cylindrical bearing that supports the rotating shaft of the auger screw, and is alternately provided at a distance in the circumferential direction, with the thick blades and thin blades that are adjacent in the circumferential direction defining a compression passage. In addition, a first inclined surface is formed on both circumferential side surfaces of the thick blade, which inclines in a direction that increases in thickness from the bottom end to the top, and a second inclined surface is formed that is connected to the top end of the first inclined surface and has a gentler inclination than the first inclined surface, so that the compression passage is configured so that its width narrows stepwise from the bottom end (inlet) to the top end (outlet).The flake ice transported by the auger screw is compressed stepwise by passing it from the wide region to the narrow region in order to form compressed ice. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-208680 Summary of the Invention [Problem to be solved by the invention]

[0004] In an auger type ice making machine, the flake ice transported by the auger screw toward the compression head is sent into the compression passage while being pushed not only in the axial direction (upward) but also in the circumferential direction (rotation direction). For this reason, in a configuration in which the lower end of the thin blade extends to a position facing the first inclined surface with a large inclination angle of the thick blade, as in the compression head of the auger type ice making machine of Patent Document 1, the circumferential force applied to the thin blade when the flake ice is compressed on the first inclined surface is large, and the thin blade may break. In addition, the flake ice near the entrance entering the compression passage is hardly compressed because the entrance is wide, and the bonding force of the flake ice on both sides of the thin blade near the entrance is weak, and the flake ice on both sides of the thin blade near the entrance is not integrated, and the flake ice on both sides moves upward at different times as the auger screw rotates. As a result, the timing at which the compression reaction force occurs on both sides of the thin blade is significantly different, and the loads applied to the thin blade do not cancel each other out on both sides, resulting in excessive load being applied to the thin blade, increasing the risk of breakage.

[0005] The present invention has been proposed in consideration of the problems inherent in the above-mentioned conventional technology, and aims to provide an auger type ice maker that can appropriately compress flake ice to produce high-quality compressed ice without breaking the thin second fixed blade of the compression head. [Means for solving the problem]

[0006] In order to overcome the above problems and achieve the intended purpose, the first means is: An auger type ice making machine comprising: an auger screw (14) rotatably disposed inside a cylindrical freezer casing (10); and a compression head (18) disposed inside an upper portion of the freezer casing (10) for compressing flake ice transported upward by the auger screw (14), The compression head (18) has a cylindrical body (18a) facing the inside of the freezer casing (10), and includes first fixed blades (20) extending a predetermined length in the vertical direction and protruding in the circumferential direction, and second fixed blades (22) having a circumferential width dimension smaller than that of the first fixed blades (20), which are alternately provided at a distance from each other in the circumferential direction on the cylindrical body (18a) facing the inside of the freezer casing (10). Compression passages (24) are formed between adjacent fixed blades in the circumferential direction, through which flake ice transported by the auger screw (14) passes and is compressed. The first fixed blade (20) has on both circumferential side surfaces an inclined surface (20a) that inclines toward the compression passage (24) from the inlet end toward the outlet end, The gist of the present invention is that the inlet end (D) of the compression passage (24) of the second fixed blade (22) is positioned so as to correspond to the outlet end (P) of the inclined surface (20a) of the first fixed blade (20). With this configuration, when the flake ice is compressed on the inlet side of the compression passage, the circumferential (rotational) force generated by the rotation of the auger screw and applied to the second fixed blade can be reduced, preventing breakage of the second fixed blade.

[0007] The second measure is characterized in that the compression passage (24) is formed so that its circumferential width decreases and its radial width increases from the inlet side to the outlet side. With this configuration, the flake ice passing through the compression passage can be compressed appropriately while preventing excessive load from being applied to the fixed blade or the freezer casing, thereby producing high-quality compressed ice while preventing damage to the fixed blade or the freezer casing.

[0008] The third aspect is characterized in that the surfaces of the first and second fixed blades (20, 22) are finished by shot blasting. With this configuration, the surface roughness of the fixed blade is given an appropriate value through the finishing process of shot blasting, which enables the flake ice to be compressed suitably, thereby producing high-quality compressed ice.

[0009] A fourth aspect of the present invention is that the surfaces of the first and second fixed blades (20, 22) are finished by shot blasting after buffing. With this configuration, the surface roughness of the fixed blade is at an appropriate value, making it possible to produce high-quality compressed ice.

[0010] A fifth aspect is characterized in that the surfaces of the first and second fixed blades (20, 22) are finished by shot blasting using a shot material of spherical particles. With this configuration, the surface roughness of the fixed blade is at an appropriate value, making it possible to produce high-quality compressed ice.

[0011] A sixth aspect of the present invention is that the surfaces of the first and second fixed blades (20, 22) are finished by shot blasting using a shot material made of zirconia and having spherical particles. With this configuration, the surface roughness of the fixed blade is at an appropriate value, making it possible to produce high-quality compressed ice.

[0012] A seventh aspect is characterized in that the surface roughness RzJIS of the first and second fixed blades (20, 22) is 1.00 to 10.00 μm. With this configuration, the ice flakes can be compressed appropriately without applying an excessive load to the fixed blade, making it possible to produce high-quality compressed ice. Effect of the Invention

[0013] According to the auger type ice making machine of the present invention, the flaky ice can be compressed appropriately without the thin second fixed blade of the compression head being broken, thereby making it possible to produce high-quality compressed ice. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic vertical sectional front view showing an auger type ice making machine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional plan view showing the compression head of the embodiment. [Diagram 3]FIG. 2 is a schematic front view showing the compression head of the embodiment. [Figure 4] FIG. 2 is a schematic front view showing the fine blade of the compression head of the embodiment. [Diagram 5] FIG. 10 is an explanatory diagram illustrating a relationship in which the circumferential width of a compression passage of a first modified embodiment narrows from the inlet side toward the outlet side. [Figure 6] FIG. 10 is an explanatory diagram illustrating a relationship in which the radial width of a compression passage of a first modified embodiment increases from the inlet side toward the outlet side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, an auger type ice making machine according to the present invention will be described below by way of a preferred embodiment with reference to the accompanying drawings. EXAMPLES

[0016] The auger type ice maker of the embodiment shown in Fig. 1 is configured such that an evaporator 12 connected to a refrigeration mechanism (not shown) is tightly wound around the outer periphery of a cylindrical refrigeration casing 10, and refrigerant is circulated through the evaporator 12 during ice-making operation to forcibly cool the refrigeration casing 10. Also, ice-making water is supplied to the refrigeration casing 10 at a predetermined level from an ice-making water tank (not shown), and when the ice-making operation is started and the refrigeration casing 10 is forcibly cooled, the ice-making water gradually begins to freeze from the inner wall surface of the casing, forming thin ice layers.

[0017] An auger screw 14 is inserted inside the refrigeration casing 10, and its lower shaft 14a is rotatably supported by a lower bearing 16 disposed at the bottom of the refrigeration casing 10, while its upper shaft 14b is rotatably supported by a compression head 18 disposed inside the upper part of the refrigeration casing 10. The auger screw 14 is formed with a spiral scraping blade 14c having an outer diameter slightly smaller than the inner diameter of the refrigeration casing 10, and is configured to scrape off thin ice that has frozen on the inner wall surface of the refrigeration casing 10 with the scraping blade 14c while transporting it upward.

[0018] 2, the compression head 18 rotatably supports the upper shaft portion 14b of the auger screw 14, and has a cylindrical body 18a facing the inside of the freezer casing 10. The cylindrical body 18a has an outer peripheral surface parallel to the axial direction of the cylindrical body 18a. The outer peripheral surface of the cylindrical body 18a extends a predetermined length in the vertical direction and protrudes in the radial direction. A compression passage 24 is formed between the outer peripheral surface of the cylindrical body 18a, the inner wall surface of the freezer casing 10, and the fixed blades 20, 22 adjacent in the circumferential direction, through which the flake ice transported by the auger screw 14 passes and is compressed. A head portion 26 is detachably disposed on the upper shaft portion 14b of the auger screw 14 and rotates integrally with the auger screw 14 at the top of the compression head 18. The head portion 26 is configured to break the continuous compressed ice pushed out of the compression passage 24 of the compression head 18 into pieces of a predetermined size. The resulting compressed ice of a specified size is then discharged and stored in a stocker (not shown).

[0019] 2 and 3, the fixed blades 20, 22 of the compression head 18 are composed of a plurality (four in this embodiment) of thick blades (first fixed blades) 20 whose lower side (the inlet side of the compression passage 24) is formed in a tapered shape, and a plurality (four in this embodiment) of thin blades (second fixed blades) 22 whose circumferential thickness is smaller than that of the thick blades 20 and whose lower side is formed in a tapered shape, and the thick blades 20 and thin blades 22 are arranged alternately in the circumferential direction. The thick blades 20 extend further downward than the thin blades 22, and the compression passages 24 are defined in the compression head 18 between the thick blades 20 and thin blades 22 adjacent to each other in the circumferential direction, and between the thick blades 20 and thick blades 20 adjacent to each other in the circumferential direction.

[0020] As shown in FIG. 3, on both circumferential side surfaces of the thick blade 20, a first thick blade inclined surface (inclined surface, first inclined surface) 20a that inclines at a first thick blade angle J1 toward the compression passage side from the lower end (the end on the inlet side of the compression passage 24) upward (the outlet side) with respect to the horizontal plane orthogonal to the axis (the rotation axis of the auger screw 14) is formed. Further, connected to the upper end (the end on the outlet side) P of the first thick blade inclined surface 20a, a second thick blade inclined surface (second inclined surface) 20b that inclines at a second thick blade angle J2 toward the compression passage side from the upper end (the outlet side) upward with respect to the horizontal plane is formed. Further, on both side surfaces of the thick blade 20, a vertical surface 20c parallel to the axis, extending from the upper end of the second thick blade inclined surface 20b to the upper end of the thick blade 20, is formed. The first thick blade angle J1 of the first thick blade inclined surface 20a is set smaller (J1 < J2) than the second thick blade angle J2 of the second thick blade inclined surface 20b. As the first thick blade angle J1, for example, 60 degrees to 75 degrees is suitable, and as the second thick blade angle J2, for example, 85 degrees to 89 degrees is suitable.

[0021] As shown in FIG. 4, on both circumferential side surfaces of the fine blade 22, a first fine blade inclined surface 22a that inclines at a first fine blade angle K1 toward the compression passage side from the lower end upward with respect to the horizontal plane orthogonal to the axis is formed, and is connected to the upper end of the first fine blade inclined surface 22a, and a second fine blade inclined surface 22b that inclines at a second fine blade angle K2 toward the compression passage side upward with respect to the horizontal plane is formed. Further, on both side surfaces of the fine blade 22, a vertical surface 22c parallel to the axis, which extends from the upper end of the second fine blade inclined surface 22b to the upper end of the fine blade 22, is formed. The first fine blade angle K1 of the first fine blade inclined surface 22a is set to be smaller (K1 < K2) than the second fine blade angle K2 of the second fine blade inclined surface 22b. As the first fine blade angle K1, for example, 75 degrees to 85 degrees is suitable, and as the second fine blade angle K2, for example, 85 degrees to 89 degrees is suitable. Further, as shown in FIG. 3, the lower end portion D of the fine blade 22 (the end portion on the inlet side of the compression passage 24) is positioned at a position corresponding to the upper end P of the first thick blade inclined surface 20a of the thick blade 20. Then, the thick blade 20 and the fine blade 22 are arranged such that a part of the first fine blade inclined surface 22a, the second fine blade inclined surface 22b, and the vertical surface 22c of the fine blade 22 faces the second thick blade inclined surface 20b of the thick blade 20 in the circumferential direction, and the vertical surface 22c of the fine blade 22 faces the vertical surface 20c of the thick blade 20 in the circumferential direction. Note that the lower end portion D of the fine blade 22 is preferably located at the same height position as the upper end P of the first thick blade inclined surface 20a of the thick blade 20, but may be offset above the upper end P of the first thick blade inclined surface 20a.

[0022] As shown in FIG. 3, the compression passage 24 formed in the compression head 18 is composed of a first compression region 24a formed between the first thick blade inclined surface 20a, 20a of the thick blades 20, 20 adjacent in the circumferential direction, a second compression region 24b formed between the second thick blade inclined surface 20b of the thick blade 20 adjacent in the circumferential direction and the first thin blade inclined surface 22a of the thin blade 22, a third compression region 24c formed between the second thick blade inclined surface 20b of the thick blade 20 adjacent in the circumferential direction and the second thin blade inclined surface 22b of the thin blade 22, a fourth compression region 24d formed between the second thick blade inclined surface 20b of the thick blade 20 adjacent in the circumferential direction and the vertical surface 22c of the thin blade 22, and a shaping region 24e formed between the vertical surface 20c of the thick blade 20 adjacent in the circumferential direction and the vertical surface 22c of the thin blade 22. In the first compression region 24a, the second compression region 24b, the third compression region 24c, and the fourth compression region 24d, the sides of the thick blade 20 and the thin blade 22 are inclined, so that the circumferential width dimension becomes narrower (smaller) from the inlet side to the outlet side of the compression passage 24, and the flake ice can be gradually compressed. In the auger ice making machine of the embodiment, the flake ice transported by the auger screw 14 and sent to the compression passage 24 undergoes a primary compression process in the first compression region 24a, a secondary compression process in the second compression region 24b, a tertiary compression process in the third compression region 24c, a quaternary compression process in the fourth compression region 24d, and finally a shaping process in the shaping region 24e where the width dimension does not change. In addition, the cross-sectional area reduction rates of the first compression zone 24a, the second compression zone 24b, the third compression zone 24c and the fourth compression zone 24d are different from one another, and the reduction rates are set to become smaller in the order of the first compression zone 24a, the second compression zone 24b, the third compression zone 24c and the fourth compression zone 24d, so that the flake ice passing through the compression passage 24 is compressed in four stages.

[0023] [Function of the embodiment] Next, the operation of the auger type ice making machine according to the embodiment will be described.

[0024] When the auger type ice maker starts making ice, the freezer casing 10 is forcibly cooled by heat exchange with the refrigerant circulating in the evaporator 12, and the ice-making water supplied from the ice-making water tank to the freezer casing 10 gradually freezes from the inner wall surface of the casing, forming thin ice layers. When the auger screw 14 disposed inside the freezer casing 10 is rotated, the thin ice is scraped off by the scraping blade 14c of the auger screw 14 and transported upward. The scraped flake ice is compressed by being forced into each compression passage 24 defined by the compression head 18 disposed inside the upper part of the freezer casing 10. The continuous compressed ice pushed up from each compression passage 24 is broken at predetermined lengths by the head portion 26, and the obtained compressed ice of a predetermined size is discharged to a stocker and stored.

[0025] To explain in detail the process by which flake ice is compressed in the compression passage 24 of the compression head 18, the flake ice transported by the auger screw 14 and sent to the compression passage 24 is first compressed in the first compression region 24a formed between the first thick blade inclined surfaces 20a, 20a of the circumferentially opposing thick blades 20, 20. In the first compression region 24a, the inclination angle of the first thick blade inclined surfaces 20a, 20a is large, so the compression rate of the flake ice is high and a large force is applied to the fixed blades 20, 20 that define the first compression region 24a. However, since the thin blade 22 does not face the first compression region 24a, the force in the rotational direction (circumferential direction) of the flake ice generated by the rotation of the auger screw 14 is not applied to the thin blade 22. Instead, the force can be absorbed by the first thick blade inclined surface 20a of the wide and strong thick blade 20, so the flake ice can be compressed suitably while preventing breakage of the thin blade 22.

[0026] The flake-shaped ice that has been primarily compressed in the first compression region 24a moves to the second compression region 24b formed between the second thick blade inclined surface 20b of the thick blade 20 and the first thin blade inclined surface 22a of the thin blade 22, where it is secondarily compressed. The reduction rate of the cross-sectional area of ​​the second compression region 24b is set to gradually decrease from the lower side to the upper side, so that the compression force can be gradually decreased as the compression of the flake-shaped ice progresses from the primary compression to the secondary compression, and the strength of the thin blade 22 can be ensured by dispersing and equalizing the compression force in the axial direction while making the first thin blade inclined surface 22a of the thin blade 22, which is prone to insufficient strength, as gentle as possible and not making it too sharp. Then, the flake-shaped ice is compressed to about 80 to 90% by the secondary compression.

[0027] The flake-shaped ice secondarily compressed in the second compression region 24b moves to a third compression region 24c formed between the second thick blade inclined surface 20b of the thick blade 20 and the second thin blade inclined surface 22b of the thin blade 22, where it is tertiarily compressed. Next, the tertiarily compressed flake-shaped ice moves to a fourth compression region 24d formed between the second thick blade inclined surface 20b of the thick blade 20 and the vertical surface 22c of the thin blade 22, where it is quaternarily compressed. The continuous compressed ice, which has been quaternarily compressed and shaped by passing through the shaping region 24e, is pushed out of the compression passage 24, broken into pieces of predetermined dimensions by the head member 26, and discharged into a stocker as compressed ice of a predetermined length.

[0028] Here, in the third and fourth compressions, most of the ice is solid and therefore brittle, so if the reduction rate of the cross-sectional area of ​​the passage is not suppressed, the ice will be compressed too rapidly, causing cracks like compression failure, and resulting in unformed, broken ice. On the other hand, if you try to compress it firmly while suppressing the reduction rate of the cross-sectional area, a distance is required in the axial direction, and the fixed blades 20, 22 will become longer, resulting in higher material costs and product size. However, in the auger-type ice maker of the embodiment, the ice is compressed in two stages, the third compression region 24c and the fourth compression region 24d, which have different reduction rates of the cross-sectional area, so that it is possible to compress the ice without crushing it, produce high-quality compressed ice, and also prevent the fixed blades 20, 22 from becoming longer.

[0029] In the auger type ice maker of the embodiment, the position of the bottom end D of the thin blade 22 is set to a position corresponding to the top end P of the first thick blade inclined surface 20a of the thick blade 20, so that the thin blade 22 is not located in the first compression region 24a, which has a large compression ratio and where the flake ice is first sent by the rotation of the auger screw 14, and the circumferential (rotational) force generated by the rotation of the auger screw 14 applied to the thin blade 22 can be reduced, preventing breakage of the thin blade 22. Also, because the ice on both sides of the thin blade 22 is connected with a sufficient width via the first compression region 24a, it moves upward at almost the same time, so that the circumferential force generated on the thin blade 22 can be offset, and breakage of the thin blade 22 can be further prevented. In addition, since the inclination of the thin blade 22 is in two stages, the first thin blade angle K1 of the first thin blade inclined surface 22a is made small to ensure strength by forming a thick shape, and the second thin blade angle K2 of the second thin blade inclined surface 22b is made large to compress the ice more gently, thereby preventing the force from the ice from becoming excessive. In addition, by decreasing the reduction rate of the cross-sectional area of ​​the compression passage 24 toward the outlet side, the ice can be compressed quickly at the bottom where it is soft and slowly at the top where it is hard, so that the load applied to the fixed blades 20, 22 can be distributed to prevent breakage, and furthermore, the ice can be prevented from being crushed due to being compressed too much.

[0030] In the auger type ice maker of the embodiment, the inclination angle of the inclined surface of the thick blade 20 and the thin blade 22 is only two kinds, but by shifting the position in the vertical direction, the reduction rate of the cross-sectional area of ​​the compression passage 24 can be finely and smoothly reduced, and the effect of distributing the load and preventing ice from being crushed can be improved. Also, the shape of the fixed blades 20, 22 is not defined by a single large arc, parabola, or other continuous curved shape, but is defined by the inclination angle and the position of the angle change point, so that it is easy to measure and manage the dimensions with a simple measuring device such as a goniometer or vernier caliper. Also, when automating the surface polishing of the fixed blades 20, 22, teaching the robot is also easy.

[0031] (About another embodiment) Next, the first to fifth alternative embodiments will be described. Note that for the first to fifth alternative embodiments, differences from the embodiment will be mainly described, and members having the same or similar functions as the embodiment will be given the same reference numerals and detailed descriptions will be omitted.

[0032] (First Alternative Example) In the auger type ice making machine of the first alternative embodiment, as shown in Fig. 5 and Fig. 6, the compression passage 24 in the compression head 18 is formed so that the circumferential width decreases and the radial width increases from the inlet side to the outlet side. That is, the compression passage 24 is configured so that the circumferential width decreases from the inlet side to the outlet side by the thin blade inclined surfaces 22a, 22b and the vertical surface 22c of the thin blade 22 that faces the second thick blade inclined surface 20b of the thick blade 20 in the circumferential direction. In the first alternative embodiment, the outer diameter dimension of the cylindrical main body 18a is formed in a truncated cone shape that decreases from the lower end (the inlet side of the compression passage 24) to the upper end (the outlet side of the compression passage 24), and the compression passage 24 is configured so that the radial width increases from the inlet side to the outlet side. As a result, the flake ice passing through the compression passage 24 is compressed in the circumferential direction while being able to expand in the radial direction, and under conditions where the ice-making capacity becomes excessive, the radial expansion of the ice is permitted, allowing the excessive force to be released and preventing ice clogging. Note that the degree of radial expansion of the compression passage 24 is slight compared to the degree of narrowing in the circumferential direction, and for example, the dimension of the outlet side in the circumferential direction is set to about 0.5 to 0.8 times the dimension of the inlet side, and the dimension of the outlet side in the radial direction is set to about 1.02 to 1.08 times the dimension of the inlet side, so that the cross-sectional area of ​​the compression passage 24 as a whole is gradually narrowed from the inlet side toward the outlet side.

[0033] In the auger type ice maker of the first alternative embodiment, compression passage 24 is configured to compress ice in the circumferential direction while allowing it to expand in the radial direction, so that even under conditions that would cause excessive ice-making capacity, the ice is allowed to expand in the radial direction, preventing excessive load from being applied and preventing ice from clogging. Also, because the compression reaction force of ice generated in the radial direction is reduced, the force exerted from the inside by ice on freezer casing 10, which has limited strength in the ice-making mechanism (it must be made as thin as possible to improve heat conduction), is reduced, preventing damage to said freezer casing 10.

[0034] (Second Alternative Example) In the auger type ice maker of the second alternative embodiment, the surface roughness of the fixed blades 20, 22 is set to a value that prevents ice clogging during ice making operation and limits the vertical length of the fixed blades 20, 22. Specifically, the surface roughness RzJIS of the fixed blades 20, 22 is preferably in the range of 1.00 to 10.00 μm, and more preferably in the range of 2.00 to 5.00 μm. The surface roughness RzJIS in the present invention is defined by the ten-point average roughness specified in JIS B0601 (2013).

[0035] Here, the surface roughness RzJIS of the conventional fixed blade was in the range of 13 to 30 μm. That is, the surface roughness of the fixed blade varies widely, and the degree of hardening of the compressed ice (ice quality) varies widely, resulting in a problem of reduced quality. In addition, because the surface roughness RzJIS varies widely, when the surface roughness RzJIS is biased toward the larger side (around 30 μm), the frictional resistance between the ice and the fixed blade increases, and in a low-temperature environment, the frictional resistance exceeds the pushing force of the auger screw 14, and ice clogging occurs easily, preventing the ice from being discharged from the compression passage. Therefore, a measure was taken to reduce the frictional resistance by attaching a heater to the outer periphery of the freezer casing near the fixed blade and increasing the heat generation of the heater, but increasing the heat generation of the heater leads to a problem of increased running costs. In addition, because of the large frictional resistance between the ice and the fixed blade, the axial reaction force pushing up the ice becomes large, and large forces are applied to the freezer casing 10 that supports the fixed blade, the geared motor that supports the freezer casing 10, and their connecting members (such as fastening bolts), which can lead to a problem of shortening the life of the ice-making mechanism, especially when used for long periods of time in a low-temperature environment where large forces are applied.

[0036] In contrast, in the auger type ice maker of the second embodiment, the surface roughness RzJIS of the fixed blades 20, 22 that come into contact with the ice is set to a range of 1.00 to 10.00 μm, which is smaller than the conventional range, so that the variation in the quality of the compressed ice can be reduced, contributing to the improvement of the quality of the compressed ice. In addition, since the range of the surface roughness RzJIS is small, when the ambient temperature or the supply water temperature drops and the ice making capacity temporarily increases, the friction resistance between the ice and the fixed blades 20, 22 is prevented from becoming excessive, and the occurrence of problems such as ice clogging can be prevented. In addition, the amount of heat generated by the heater is small, so that the running cost can be reduced. Furthermore, the load applied to the auger screw 14 is also reduced, and the load applied to the refrigeration casing 10, the geared motor, and other joints is also reduced, improving reliability. In addition, when the surface roughness RzJIS is in the range of 1.00 to 10.00 μm, the length of the tapered portions of the fixed blades 20, 22 (the portions forming the inclined surfaces 20a, 20b and the inclined surfaces 22a, 22b), the inclination angle, the cross-sectional area of ​​the compression passage 24, etc. may be designed to appropriate values ​​depending on the ice-making capacity, the shape of the auger screw 14, the rotation speed, etc.

[0037] (Third Alternative Example) In the auger type ice making machine of the third alternative embodiment, the surfaces of the fixed blades 20, 22 are finished by shot blasting to an optimum surface roughness (RzJIS=1.00 to 10.00 μm).

[0038] Conventionally, the surface (casting surface) of the fixed blade cast by the lost wax method or the like has been subjected to a finishing process by extruded horn polishing, barrel polishing, buff polishing, etc. Finishing processes by extruded horn polishing and barrel polishing require less processing time and are less expensive than buff polishing, but it is difficult to reduce the surface roughness, and the surface roughness RzJIS can only be kept within a range of about 13 to 30 μm, and as described in the explanation of the second alternative embodiment, there are problems such as a decrease in the quality of compressed ice, the occurrence of ice clogging during ice-making operation, and a shortened life of the ice-making mechanism due to the variation in the surface roughness of the fixed blade.

[0039] Furthermore, when the surface of the fixed blade is finished by the buffing, the surface roughness RzJIS of the fixed blade can be reduced to about 0.1 to 1.0 μm, and the quality of the compressed ice can be improved. However, if the surface roughness RzJIS becomes too small, the frictional resistance between the ice and the fixed blade decreases, making it difficult to compress the ice. For this reason, it was necessary to lengthen the vertical dimensions of the fixed blade itself and its tapered portion to increase the degree of compression by the inclined surface of the compression passage 24, or to reduce the cross-sectional area of ​​the compression passage 24 as a whole. However, if the vertical dimensions of the fixed blade are lengthened, there is a problem that the size of the product increases, which reduces the marketability and increases the material cost, and if the compression passage 24 is narrowed, problems such as the ice being easily clogged when the ice-making capacity increases in a low-temperature environment are likely to occur. Also, if the taper angle is increased (the compression passage 24 narrows suddenly) to prevent the size from increasing, the ice passing through the compression passage 24 is compressed suddenly, which leads to a problem that the ice breaks and cannot be formed normally.

[0040] In the auger type ice maker of the third embodiment, the surface of the fixed blades 20, 22 is finished by shot blasting, so that the surface roughness RzJIS of the fixed blades 20, 22 can be easily adjusted to the range of 1.00 to 10.00 μm (optimum range) suitable for making compressed ice. The range of 1.00 to 10.00 μm of the surface roughness RzJIS of the fixed blades 20, 22 is approximately halfway between the range of 13 to 30 μm that can be processed by extruded horn polishing and the range of 0.1 to 1.0 μm that can be processed by buff polishing, so that high-quality compressed ice can be made without lengthening the fixed blades 20, 22 themselves or the tapered portion, and ice clogging during ice making operation can be prevented, running costs can be reduced, and the reliability of the ice making mechanism can be improved. In addition, by finishing by shot blasting, if the surface roughness of the fixed blades 20, 22 before finishing is generally smaller than the optimum range, the surface roughness can be stably kept within the optimum range. Furthermore, by applying a finishing process by shot blasting to the surface of the cylindrical body 18a of the compression head 18 with which the ice comes into contact, the fixed blades 20, 22 themselves and the tapered portions can be further shortened and high-quality compressed ice can be produced.

[0041] In the auger type ice maker of the third embodiment, although it is possible to bring the cast surface (the surface of the fixed blades 20, 22) having a general roughness into the optimum range by directly shot blasting, it is preferable to polish or cut the cast surface to a certain level of surface roughness and then finish it by shot blasting. The processing of the cast surface is preferably buff polishing, which can reduce the roughness, but other polishing processes such as electrolytic polishing, barrel polishing, and grinding wheel polishing, and cutting with an end mill can also be used. When the surfaces of the fixed blades 20, 22 are polished before the finishing process by shot blasting, it is possible to make the surface roughness RzJIS after shot blasting in the range of 2.0 to 5.0 μm by processing the surface roughness RzJIS before shot blasting to 3.2 μm or less, for example, depending on the processing conditions of the shot blasting (the material, size, shape, and processing time of the shot material). In addition, in polishing and cutting processes, it is common to specify only the upper limit of roughness, and it is not common to keep the roughness within the upper and lower limits. However, by combining it with shot blasting, it is possible to keep the roughness within the upper and lower limits. Also, in cases where the roughness before shot blasting is smaller than the target roughness, i.e., when the shot blasting is used to roughen the surface, the finished roughness can be stabilized by keeping the shot blasting conditions constant. By using shot blasting as the finishing process, even if the surface is rougher than the optimal range, such as a cast surface, it is possible to first smooth it (reducing the roughness) by polishing or cutting in the previous process and then roughen it (increasing the roughness), so that the surface roughness can be stably kept within the optimal range regardless of the roughness of the cast surface. In addition, when the casting surface (the surface of the fixed blades 20, 22 before shot blasting) is relatively smooth (when the surface roughness RzJIS is about 12.5 μm or less), the rough surface can be smoothed by extending the shot blasting time, so it is also possible to apply shot blasting directly to the casting surface without polishing, thereby keeping the surface roughness within the above-mentioned optimal range.

[0042] (Fourth Alternative Example) In the auger type ice making machine of the fourth embodiment, the fixed blades 20, 22 are finished by shot blasting using spherical particles as the shot material in the third embodiment. Even if the spherical particles are worn down by repeated shot blasting, their shape remains approximately spherical and they become smaller, and when they reach a certain size or smaller, they are selected and removed by a filter in the processing machine. Therefore, there is little change in the polishing characteristics due to deterioration of the shot material, and the surface roughness of the processed fixed blades 20, 22 can be stably kept within the optimal range. In other words, the surface roughness of the fixed blades 20, 22 finished by shot blasting using spherical particle shot material is within the optimal range suitable for producing compressed ice, and good quality compressed ice can be produced.

[0043] (Fifth Alternative Example) In the auger type ice maker of the fifth embodiment, the fixed blades 20, 22 are finished by shot blasting using spherical particles made of zirconia (zirconium dioxide) as the shot material in the third embodiment. Zirconia is very hard, with a Mohs hardness of 8 to 8.5, so even if the particles are spherical, the effect of scraping the surface is large and processing is fast. Also, in the auger type ice maker of the fifth embodiment, as in the fourth embodiment, the surface roughness of the fixed blades 20, 22 finished by shot blasting using the shot material of spherical particles falls within the optimum range suitable for making compressed ice, and good quality compressed ice can be made.

[0044] [Example of change] The present application is not limited to the configurations of the above-mentioned examples, etc., and other configurations may be appropriately adopted. Furthermore, the configurations described in the examples, etc., are not limited to the following modified examples, and various embodiments may be adopted within the scope of the present invention. (1) The number of thick blades and thin blades on the compression head is not limited to four each, but may be two or more each. (2) The number of inclined surfaces formed on the thick blade and the thin blade is not limited to two, and may be three or more. (3) The configurations of the first to fifth alternative embodiments can be appropriately selected and adopted in the embodiment if they can be combined. [Explanation of symbols]

[0045] 10 refrigeration casing, 14 auger screw, 18 compression head, 18a cylindrical body 20 Thick blade (1st fixed blade), 20a 1st thick blade sloped surface (slanted surface), 22 Thin blade (2nd fixed blade) 24 Compression passage, D Lower end of thin blade (end on the inlet side) P Upper end of the first thick blade inclined surface (end on the outlet side)

Claims

1. An auger type ice making machine comprising an auger screw rotatably disposed inside a cylindrical freezer casing, and a compression head disposed inside an upper portion of the freezer casing and compressing flake ice transported upward by the auger screw, The compression head has a cylindrical body facing the inside of the freezer casing, and includes a first fixed blade extending a predetermined length in the vertical direction and projecting in the circumferential direction, and a second fixed blade having a circumferential width smaller than that of the first fixed blade, which are alternately provided at a distance in the circumferential direction, and a compression passage is formed between adjacent fixed blades in the circumferential direction, through which flake ice transported by the auger screw passes and is compressed; An inclined surface is formed on each of both circumferential side surfaces of the first fixed blade, the inclined surface being inclined toward the compression passage from the inlet end toward the outlet end of the compression passage, The inlet end of the compression passage of the second fixed blade is positioned to correspond to the outlet end of the inclined surface of the first fixed blade. The auger type ice maker is characterized by the following:

2. 2. The auger type ice making machine according to claim 1, wherein the compression passage is formed so that its circumferential width decreases and its radial width increases from the inlet side to the outlet side.

3. 2. The auger type ice making machine according to claim 1, wherein the surfaces of said first and second fixed blades are finished by shot blasting.

4. 2. The auger type ice making machine according to claim 1, wherein the surfaces of said first and second fixed blades are finished by shot blasting after buffing.

5. 2. The auger type ice making machine according to claim 1, wherein the surfaces of said first and second fixed blades are finished by shot blasting using a shot material having spherical particles.

6. 2. The auger type ice making machine according to claim 1, wherein the surfaces of said first and second fixed blades are finished by shot blasting using a shot material made of zirconia and having spherical particles.

7. 7. The auger type ice making machine according to claim 1, wherein the surface roughness RzJIS of the first and second fixed blades is 1.00 to 10.00 μm.

Images