Beverage extraction device

Abstract

To provide a beverage extraction device capable of reducing a burden of cleaning.SOLUTION: In a beverage extraction device 100, a diamond-like carbon layer 20 containing diamond-like carbon is provided in a portion 10 through which an extracted liquid of at least one of an extraction part 1 and a supply tube 3 passes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a beverage brewing machine, and more particularly to a beverage brewing machine having an extracting unit. [Background technology]

[0002] BACKGROUND ART Conventionally, beverage extraction devices equipped with an extraction unit are known (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a beverage extraction device that includes a storage container (extraction unit) to which powdered raw materials and hot water are supplied, a filter unit that filters and extracts the stirred liquid stirred in the storage container, and a silicone tube that transports the stirred liquid as a filtered beverage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-162856 Summary of the Invention [Problem to be solved by the invention]

[0005] Although not disclosed in Patent Document 1, in beverage extraction machines, components of the extract adhere to the extraction unit (storage container) and supply pipe (silicon tube), requiring the user to clean the beverage extraction machine. However, once adhered, components containing oil from the extract are difficult to remove, making cleaning a time-consuming process. In particular, beverage extraction machines used in stores tend to be used frequently, resulting in a large amount of extract components adhering to the machine, which are difficult to remove and require additional time and effort. This places a burden on the user, and therefore a beverage extraction machine that can reduce the burden of cleaning is desired.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a beverage extraction device that can reduce the burden of cleaning. [Means for solving the problem]

[0007] In order to achieve the above object, the present inventors conducted extensive research and discovered that providing a diamond-like carbon layer on a portion through which the extract passes can prevent components of the extract from adhering. This led to the completion of the present invention. That is, a beverage extraction device according to one aspect of the present invention includes an extraction unit that receives powdered ingredients and a liquid and extracts an extract, a filtration unit that filters the extract extracted by the extraction unit, and a supply pipe that supplies the extract filtered by the filtration unit to a beverage container as a beverage. A diamond-like carbon layer containing diamond-like carbon is provided on a portion of at least one of the extraction unit and the supply pipe through which the extract passes.

[0008] In one aspect of the beverage extraction device of the present invention, as described above, a diamond-like carbon layer containing diamond-like carbon is provided in the portion of at least one of the extraction unit and the supply pipe through which the extract passes. By forming this diamond-like carbon layer, it is possible to suppress adhesion of extract components. The inventors of the present application have learned this through experiments (examples) described below. Furthermore, because adhesion of extract components can be suppressed, the amount of extract components that adhere is reduced, making cleaning easier for the user. As a result, the burden of cleaning can be reduced.

[0009] In the beverage extractor according to the above aspect, at least one of the extraction unit and the supply pipe is preferably made of resin or metal, and a diamond-like carbon layer is provided on the surface of the portion through which the extract passes. With this configuration, even if the extraction unit and the supply pipe are made of metal or resin, the diamond-like carbon layer provided on the surface can prevent components of the extract from adhering to them.

[0010] In this case, preferably, at least one of the extraction part and the supply pipe has an intermediate layer between the part through which the extract passes and the diamond-like carbon layer, which improves the adhesion between the diamond-like carbon layer and the part through which the extract passes. By providing an intermediate layer that improves the adhesion between the diamond-like carbon layer and the part through which the extract passes, the bonding strength between the part through which the extract passes and the diamond-like carbon layer can be increased, thereby preventing the diamond-like carbon layer from dissociating from the part through which the extract passes.

[0011] In the beverage extraction device according to the above aspect, a diamond-like carbon layer having a higher proportion of diamond structures than graphite structures is preferably provided in at least one of the extraction unit and the supply pipe, in a portion through which the extract passes. With this configuration, the higher the proportion of diamond structures, the more effectively the adhesion of extract components can be suppressed. This was discovered by the inventors through experiments (examples) described below.

[0012] The beverage extraction device according to the above aspect preferably includes a polybasic acid storage section for storing a polybasic acid, which is a divalent or higher acid, to be supplied to the extraction section, and the portion of the extraction section through which the extract passes and the portion of the supply pipe through which the extract passes are washed with the polybasic acid and coated with the polybasic acid. With this configuration, the formation of the polybasic acid coating makes the portion of the extraction section through which the extract passes and the portion of the supply pipe through which the extract passes hydrophilic, forming a water coating that prevents oily deposits from adhering. As a result, the portion through which the extract passes can be easily cleaned during cleaning, and components of the extract are less likely to adhere to the portion through which the extract passes after cleaning, making cleaning easier.

[0013] In this case, preferably, the polybasic acid is citric acid, and the device further includes a control unit that cleans the portion of the extraction unit through which the extract passes and the portion of the supply pipe through which the extract passes with citric acid and controls the formation of a citric acid coating. With this configuration, the formation of a citric acid coating makes the portion of the extraction unit through which the extract passes and the portion of the supply pipe through which the extract passes hydrophilic, forming a water coating and preventing oily deposits from adhering. The inventors of the present application have learned this through experiments (Examples) described below. Furthermore, because the control unit performs cleaning and coating formation, unlike when the user performs cleaning and coating formation, the user's effort can be reduced. [Effects of the Invention]

[0014] According to the present invention, as described above, it is possible to provide a beverage extraction device that can reduce the burden of cleaning. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a block diagram showing the configuration of a beverage extraction device according to a first embodiment and a third embodiment. [Figure 2] FIG. 3 is a diagram showing a portion through which an extract passes in a state in which a diamond-like carbon layer is formed in the first embodiment. [Figure 3] FIG. 2 is a diagram showing a portion through which an extract passes in a state in which a diamond-like carbon layer and an intermediate layer are formed in the first embodiment. [Figure 4] 1 is a graph showing the amount of adhesion of components of an extract with and without a diamond-like carbon layer. [Figure 5] 1 is a graph showing the relationship between the proportion of diamond structures in a diamond-like carbon layer and the amount of adhesion of components of an extract. [Figure 6] FIG. 10 is a block diagram showing the configuration of a beverage extraction device according to a second embodiment. [Figure 7] FIG. 10 is a block diagram showing another configuration of the beverage extraction device in the second embodiment. [Figure 8]FIG. 10 is a diagram showing a portion through which an extract passes in a state in which a diamond-like carbon layer and a coating are formed in the second embodiment. [Figure 9] 1 is a graph showing the amount of adhesion of extract components in a comparative example and examples 3 to 5. [Figure 10] 1 is a graph showing the amount of adhesion of extract components in Examples 6 to 8. [Figure 11] FIG. 10 is a diagram showing the contact angle of pure water in Example 9. [Figure 12] FIG. 10 is a diagram showing the contact angle of pure water in Example 10. [Figure 13] FIG. 10 is a diagram showing the contact angle of pure water in Example 11. [Figure 14] FIG. 12 is a diagram showing the contact angle of pure water in Example 12. [Figure 15] FIG. 10 is a diagram showing the contact angle of pure water in a comparative example. [Figure 16] 1 is a graph showing the relationship between the contact angle and the amount of adhesion of components of the extract. [Figure 17] FIG. 10 is a diagram showing a microstructure in a third embodiment. [Figure 18] 1 is a graph showing the amount of adhesion of extract components in Examples 13 to 16. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0017] [First embodiment] The configuration of a beverage extraction machine 100 according to a first embodiment will be described with reference to FIGS.

[0018] As shown in Figure 1, beverage brewing machine 100 is configured to brew and serve a beverage. Beverage brewing machine 100 is a machine that serves coffee beverages. For example, beverage brewing machine 100 is used as counter fixtures or vending machines placed on counters in stores.

[0019] The beverage extraction machine 100 includes an extraction unit 1, a filtering unit 2, a supply pipe 3, a discharge port 4, a liquid storage unit 5, a powder ingredient storage unit 6, a pump 7, a fan 8, and a control unit 9.

[0020] The extraction unit 1 is supplied with powdered raw material from the powdered raw material storage unit 6 and with liquid from the liquid storage unit 5. The extraction unit 1 is configured so that the powdered raw material and liquid are mixed and an extract is extracted. Specifically, the powdered raw material and liquid supplied to the extraction unit 1 are mixed by blowing air from a pump 7 into the extraction unit 1. The extraction unit 1 is formed in a cylindrical shape with an internal space. For example, the extraction unit 1 is formed from resin.

[0021] The filtration unit 2 is configured to produce a beverage by filtering the extract extracted by the extraction unit 1. The filtration unit 2 includes a metal mesh filter, a paper filter, and a support unit that supports the metal mesh filter and the paper filter. The filtration unit 2 is located downstream of the extraction unit 1.

[0022] The supply pipe 3 is configured to supply the extract filtered by the filtration unit 2 as a beverage to the beverage container 50. The supply pipe 3 includes a plurality of resin pipes and metal joints that connect the plurality of pipes together. The supply pipe 3 is connected to the filtration unit 2.

[0023] The outlet 4 is attached to the downstream end of the supply pipe 3. The outlet 4 is configured to supply the extract that has passed through the supply pipe 3 to the beverage container 50. The outlet 4 is, for example, a nozzle.

[0024] The liquid storage unit 5 is configured to store a liquid. The liquid storage unit 5 is configured to supply hot water as the liquid to the extraction unit 1. The liquid storage unit 5 includes a tank for storing water and a heater for heating the water. The liquid storage unit 5 and the extraction unit 1 are connected by piping. As an example, the piping is provided with a valve, and the amount of liquid supplied to the extraction unit 1 is configured to be adjusted by the opening degree of the valve.

[0025] The powdered raw material storage unit 6 is configured to store the powdered raw material to be supplied to the extraction unit 1. The powdered raw material storage unit 6 has a blade (not shown). The blade is configured to grind raw materials such as coffee beans to produce powdered raw materials. As an example, a chute is provided between the powdered raw material storage unit 6 and the extraction unit 1, and is configured to supply a predetermined amount of powdered raw material to the extraction unit 1.

[0026] The pump 7 is configured to supply air to the extraction unit 1. The air supplied from the pump 7 is used to extract the powdered raw material and the liquid from the mixed liquid by pressure, and is also used to push the mixed liquid by pressure into the filtration unit 2.

[0027] Fan 8 is used to exhaust steam to the outside within extraction unit 1. By exhausting steam to the outside with fan 8, it is possible to prevent steam from flowing inside powder raw material storage unit 6.

[0028] The control unit 9 is configured to control the operation of the beverage brewing machine 100. The control unit 9 is configured to adjust a valve provided in a pipe connecting the liquid storage unit 5 and the extraction unit 1 to control the flow rate. The control unit 9 is also configured to control the supply of a predetermined amount of powdered raw material from the powdered raw material storage unit 6 to the extraction unit 1. The control unit 9 is also configured to control the driving of the fan 8. The control unit 9 accepts a selection operation by the user and controls the beverage brewing machine 100 to supply the selected beverage.

[0029] The flow of producing an extracted beverage will be explained using coffee as an example. The control unit 9 grinds coffee beans stored in the powdered raw material storage unit 6 to produce powdered raw materials. The control unit 9 supplies a predetermined amount of powdered raw materials from the powdered raw material storage unit 6 to the extraction unit 1. The control unit 9 also heats water stored in the liquid storage unit 5 to produce hot water, and supplies a predetermined amount of hot water to the extraction unit 1. At this time, the control unit 9 controls the opening and closing of valves provided in the piping.

[0030] The control unit 9 controls the pump 7 to blow air into the extraction unit 1. The air supplied from the pump 7 mixes the powdered ingredients and hot water supplied to the extraction unit 1, producing coffee as an extract. At this time, the fan 8 is driven to exhaust steam from inside the extraction unit to the outside.

[0031] The control unit 9 further controls the pump 7 to supply the extract to the filtration unit 2. The coffee extract filtered by the filtration unit 2 passes through the supply pipe 3 and is supplied from the outlet 4 to the beverage container 50.

[0032] The control unit 9 is configured to supply liquid from the liquid storage unit 5 to the extraction unit 1 after the beverage has been prepared, to clean the extraction unit 1. The cleaning liquid is discharged from a discharge port (not shown) separate from the discharge port 4.

[0033] As shown in FIG. 2, a diamond-like carbon layer 20 containing diamond-like carbon is provided in a portion 10 of at least one of the extraction unit 1 and the supply pipe 3 through which the extract passes. In the case of the extraction unit 1, the portion 10 through which the extract passes is, for example, the interior where a liquid and a powdered raw material are supplied and the extract is produced. In the case of the supply pipe 3, the portion 10 through which the extract passes is, for example, the interior of multiple pipes through which the extract passes and a joint. In the first embodiment, the diamond-like carbon layer 20 is formed in both the portion 10 of the extraction unit 1 through which the extract passes and the portion 10 of the supply pipe 3 through which the extract passes. In FIG. 2, the portion 10 through which the extract passes is depicted as a flat plate for convenience. Furthermore, a diamond-like carbon layer 20 may also be formed on the opposite side of the extraction unit 1 and the supply pipe 3 from the portion 10 through which the extract passes.

[0034] Diamond-like carbon is carbon containing a diamond structure (sp3 structure) and a graphite structure (sp2 structure). Preferably, the diamond-like carbon layer 20 is configured so that the proportion of the diamond structure is greater than the proportion of the graphite structure. For example, the proportion of the diamond structure is greater than 60% and less than 100%.

[0035] The diamond-like carbon layer 20 is formed on the portion 10 through which the extract passes by a dry plating method including chemical vapor deposition and physical vapor deposition. The portion 10 through which the extract passes is made of metal or resin. Examples of metals include stainless steel, chromium, nickel, and molybdenum. Examples of resins include polypropylene, polyphenylene sulfide, and polycarbonate. In the case of the extraction unit 1, the portion 10 through which the extract passes is made of, for example, polypropylene. In the case of the supply pipe 3, the portion 10 through which the extract passes is made of, for example, multiple pipes through which the extract passes are made of polypropylene, and the joints are made of stainless steel. Note that, although FIG. 2 shows the thickness of the diamond-like carbon layer 20 as being smaller than the thickness of the portion 10 through which the extract passes, the thickness of the diamond-like carbon layer 20 may be greater than the thickness of the portion 10 through which the extract passes.

[0036] The beverage extraction device 100 is manufactured by combining an extraction unit 1 provided with a diamond-like carbon layer 20, a filtration unit 2, and a supply pipe 3 provided with a diamond-like carbon layer 20. A dry plating method is used to provide the diamond-like carbon layer 20 on the extraction unit 1. Dry plating methods include chemical vapor deposition and physical vapor deposition.

[0037] Chemical vapor deposition is a method of forming a thin film by placing an object in a container, supplying a source gas containing a coating substance, creating a vacuum, and then using heat, plasma, or light to cause a chemical reaction.

[0038] Physical vapor deposition is a method of forming a thin film by placing the target object and the material to be evaporated (coating substance) in a container, heating the target object to vaporize it, and then solidifying the coating substance on the surface of the target object. One example of physical vapor deposition is vacuum deposition, in which the pressure inside the container is reduced to near vacuum to make it easier to evaporate the coating substance.

[0039] In the first embodiment, the extraction unit 1 and the supply pipe 3 are each placed in a container, and the diamond-like carbon is placed in the container, and then the diamond-like carbon layer 20 is formed by physical vapor deposition or chemical vapor deposition. At this time, the area other than the portion 10 through which the extract passes may be masked.

[0040] The diamond-like carbon layer 20 has low friction characteristics and chemical stability, making it difficult for substances contained in the extract to adhere to the diamond-like carbon layer 20. One example of a substance contained in the extract is trioleic acid, an oil contained in coffee.

[0041] 3, an intermediate layer 30 may be provided between the diamond-like carbon layer 20 and the portion 10 of the extraction unit 1 through which the extract passes and the portion 10 of the supply pipe 3 through which the extract passes. The intermediate layer 30 contains, for example, nitrogen, titanium, carbon, boron, etc., and is formed by implanting ions that form the intermediate layer 30 when forming the diamond-like carbon layer 20.

[0042] The intermediate layer 30 is configured to improve adhesion between the diamond-like carbon layer 20 and the portion 10 through which the extract passes. In particular, the intermediate layer 30 can improve the bonding strength between the diamond-like carbon layer 20 and the portion 10 through which the extract passes, which is made of metal. Furthermore, when the portion 10 through which the extract passes is made of resin, the intermediate layer 30 is configured to have a thermal expansion coefficient between that of the diamond-like carbon layer 20 and that of the portion 10 through which the extract passes, which is made of resin. This makes it possible to prevent the diamond-like carbon layer 20 from dissociating due to the difference in thermal expansion coefficient between the diamond-like carbon layer 20 and the portion 10 through which the extract passes, which is made of resin, when hot water is supplied from the liquid storage section 5 and the portion 10 through which the extract passes is heated.

[0043] [First Example] Experiments were conducted to confirm the effects of the present invention. In Example 1, the amount of adhesion of extract components was measured when a diamond-like carbon layer 20 was formed on stainless steel. Trioleic acid, an oil component in coffee, was used as the extract component. Specifically, a comparative example without a diamond-like carbon layer and Examples 1 and 2 with a diamond-like carbon layer 20 were produced, and the amount of adhesion of trioleic acid was measured. The amount of adhesion was calculated from the peak intensity of trioleic acid using Fourier transform infrared spectroscopy.

[0044] In Fig. 4, the adhesion amounts calculated from the peak intensity are plotted on the vertical axis. Fig. 4 shows the adhesion amounts of Examples 1 and 2, with the adhesion amount of the Comparative Example being set to 1. As shown in Fig. 4, the adhesion amount was 0.3 in the Example and 0.28 in Example 2. Therefore, the inventors of the present application have discovered that the adhesion of trioleic acid can be suppressed by providing the diamond-like carbon layer 20.

[0045] Furthermore, since the amount of adhesion in both Examples 1 and 2 was smaller than that in the comparative example in which no diamond-like carbon layer was provided, the inventors of the present application found that the effect of providing the diamond-like carbon layer 20 in suppressing adhesion of components of the extract solution is highly reproducible.

[0046] [Second Example] In the second example, the ratio of the diamond structure to the graphite structure in the diamond-like carbon layer 20 was changed, and the amount of adhesion was measured.

[0047] In Figure 5, the horizontal axis plots the ratio of diamond structures to the total of diamond structures (sp3) and graphite structures (sp2), and the vertical axis plots the amount of adhesion. The maximum allowable range of the amount of adhesion is represented by S. As shown in Figure 5, it was found that the greater the ratio of diamond structures, the lower the amount of adhesion. It was also found that it is preferable to have the diamond structures exceed 60% (63%). From the above, the inventors of the present application have discovered that the amount of adhesion can be reduced by the diamond-like carbon layer 20, and that the amount of adhesion can be further reduced by having a higher proportion of diamond structures than graphite structures.

[0048] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0049] In the first embodiment, as described above, a diamond-like carbon layer 20 containing diamond-like carbon is provided in the portion 10 of at least one of the extraction unit 1 and the supply pipe 3 through which the extract passes. By forming the diamond-like carbon layer 20, adhesion of extract components can be suppressed. The inventors of the present application have learned this through experiments (examples) described below. Furthermore, because adhesion of extract components can be suppressed, the amount of extract component adhesion is reduced, making cleaning easier for the user. As a result, the burden of cleaning can be reduced.

[0050] Furthermore, in the first embodiment, as described above, at least one of the extraction part 1 and the supply pipe 3 is made of resin or metal, and the diamond-like carbon layer 20 is provided on the surface of the part 10 through which the extract passes. Thus, even when the extraction part 1 and the supply pipe 3 are made of metal or resin, by providing the diamond-like carbon layer 20 on the surface, it is possible to prevent components of the extract from adhering to them.

[0051] Furthermore, in the first embodiment, as described above, at least one of the extraction unit 1 and the supply pipe 3 has an intermediate layer 30 between the portion 10 through which the extract passes and the diamond-like carbon layer 20, which improves adhesion between the diamond-like carbon layer 20 and the portion 10 through which the extract passes. By providing the intermediate layer 30 which improves adhesion between the diamond-like carbon layer 20 and the portion 10 through which the extract passes, the bonding strength between the portion 10 through which the extract passes and the diamond-like carbon layer 20 can be increased, and therefore, dissociation of the diamond-like carbon layer 20 from the portion 10 through which the extract passes can be suppressed.

[0052] In the first embodiment, as described above, the diamond-like carbon layer 20, which has a higher proportion of diamond structure than graphite structure, is provided in the portion 10 of at least one of the extraction unit 1 and the supply pipe 3 through which the extract passes. As a result, the adhesion of components of the extract can be more effectively suppressed as the proportion of diamond structure increases. The inventors of the present application discovered this through experiments (examples) described below.

[0053] [Second embodiment] The configuration of a beverage brewing machine 200 according to a second embodiment of the present invention will be described with reference to Figures 6 to 16. In the figures, the same components as those in the beverage brewing machine 100 according to the first embodiment are designated by the same reference numerals.

[0054] As shown in FIG. 6, the second embodiment further includes a polybasic acid storage unit 11 and a flow path switching unit 12. The polybasic acid storage unit 11 is configured to store a polybasic acid, which is a divalent or higher acid. Examples of polybasic acids include phosphoric acid, oxalic acid, and polybasic carboxylic acids. Examples of polybasic carboxylic acids include citric acid and malic acid. The polybasic acid storage unit 11 may store a solid polybasic acid or a polybasic acid solution. The polybasic acid includes polybasic acids and their salts. The polybasic acid storage unit 11 may be, for example, a tank.

[0055] The flow path switching unit 12 is configured to switch between a flow path that supplies liquid (hot water) from the liquid storage unit 5 to the extraction unit 1 and a flow path that supplies a polybasic acid from the polybasic acid storage unit 11 to the extraction unit 1. As shown in Fig. 6, the flow path switching unit 12 may be a three-way valve, or as shown in Fig. 7, the flow path switching unit 12 may be a duckbill (check valve).

[0056] The control unit 9 is configured to control the switching of the flow path switching unit 12. When producing an extracted beverage, the control unit 9 controls the flow path switching unit 12 to switch to a flow path that supplies liquid (hot water) from the liquid storage unit 5 to the extraction unit 1. If the flow path switching unit 12 is a three-way valve, the control unit 9 switches the flow path so that the liquid storage unit 5 and the extraction unit 1 are connected but not connected to the polybasic acid storage unit 11. If the flow path switching unit 12 is a check valve, the control unit 9 controls to open the valve of the piping connecting the liquid storage unit 5 and the extraction unit 1 and close the valve of the flow path connecting the polybasic acid storage unit 11 and the extraction unit 1.

[0057] During cleaning, the control unit 9 controls the flow path switching unit 12 to select a flow path that supplies a polybasic acid from the polybasic acid storage unit 11 to the extraction unit 1. If the flow path switching unit 12 is a three-way valve, the control unit 9 switches the flow path so that the polybasic acid storage unit 11 and the extraction unit 1 are connected but not connected to the liquid storage unit 5. If the flow path switching unit 12 is a check valve, the control unit 9 controls the valve of the piping connecting the polybasic acid storage unit 11 and the extraction unit 1 to be opened and the valve of the flow path connecting the liquid storage unit 5 and the extraction unit 1 to be closed.

[0058] As shown in Figure 8, the portion 10 of the extraction unit 1 through which the extract passes and the portion 10 of the supply pipe 3 through which the extract passes are washed with a polybasic acid, and a coating 40 of the polybasic acid is formed. The polybasic acid coating 40 reduces the contact angle between the portion 10 of the extraction unit 1 through which the extract passes and the portion 10 of the supply pipe 3 through which the extract passes, making them hydrophilic. Therefore, the formation of the polybasic acid coating 40 forms a water coating between the portion 10 of the extraction unit 1 through which the extract passes and the portion 10 of the supply pipe 3 through which the extract passes, making it difficult for oil to adhere.

[0059] The flow during cleaning of the extraction unit 1 will be described. The control unit 9 controls the supply of polybasic acid stored in the polybasic acid storage unit 11 to the extraction unit 1. If the polybasic acid needs to be diluted, after the supply of the polybasic acid is completed, the flow path is switched to supply liquid from the liquid storage unit 5. The concentration of the polybasic acid solution is set, for example, to between 1% and 10%, preferably between 1.05% and 6.30%. The supplied polybasic acid solution passes from the extraction unit 1 through the filtration unit 2 and flows into the supply pipe 3. In this case, the speed of the polybasic acid solution flowing into the supply pipe 3 may be slowed down by adjusting the amount of air supplied from the pump 7.

[0060] After the polybasic acid has been poured, drying is carried out so that a polybasic acid coating is formed. Drying methods include natural drying and air drying. Air drying is carried out by blowing air from a pump 7 or by reverse rotation of a fan 8. Excess polybasic acid solution may also be removed by air blowing. After the coating 40 is formed, rinsing may be carried out to remove excess polybasic acid solution.

[0061] The polybasic acid coating 40 may be formed in advance during the manufacturing of the beverage extraction device 200. For example, it may be formed by immersing the extraction part 1 and the supply pipe 3 in a solution of the polybasic acid and drying it. The drying method may be natural drying, air drying, or wiping. After drying, the polybasic acid solution may be removed by air removal. Instead of immersing the extraction part 1 and the supply pipe 3 in the solution of the polybasic acid, the solution of the polybasic acid may be sprayed or applied.

[0062] [Third Example] Experiments were conducted to verify the effects of the present invention. In Example 3, the amount of components of the extract adhered to stainless steel when a coating 40 was formed using citric acid was measured. Trioleic acid, an oil component in coffee, was used as the extract component. In Example 3, the coating 40 was formed by immersion in a solution with a citric acid concentration of 1.05% for 3 minutes. In Example 4, the coating 40 was formed by changing the immersion time to 15 minutes without changing the citric acid concentration from Example 3. In Example 5, the coating 40 was formed by changing the immersion time to 30 minutes without changing the citric acid concentration from Example 3. In the comparative example, no citric acid coating was formed. Note that in the comparative example and examples, the diamond-like carbon layer 20 was not provided in order to obtain the effect of the coating 40 alone. The amount of adhesion was calculated from the peak intensity of trioleic acid using Fourier transform infrared spectroscopy.

[0063] FIG. 9 shows the results for Examples 3 to 5 and the Comparative Example. The graph in FIG. 9 plots the amount of trioleic acid attached on the vertical axis. In FIG. 9, the amount of attachment for the Comparative Example is set to 1. In Example 3, the amount of attachment was approximately 0.25. In Example 4, the amount of attachment was approximately 0.17. Furthermore, in Example 6, the amount of attachment was approximately 0.13. Therefore, the inventors of the present invention have discovered that the formation of a citric acid coating 40 can suppress the attachment of components of the extract. Furthermore, since the amount of attachment was low in Example 4, which had a longer immersion time than Example 3, and the amount of attachment was also low in Example 5, which had a longer immersion time than Example 4, the inventors of the present invention have discovered that the amount of attachment can be further reduced by extending the immersion time. Note that, although the examples do not include a diamond-like carbon layer 20, it is believed that providing a diamond-like carbon layer 20 would also provide equivalent or better effects.

[0064] [Fourth Example] In Example 4, the amount of extract components attached to stainless steel samples was measured when coatings 40 were formed on the stainless steel samples by varying the concentration or temperature of the citric acid solution. Trioleic acid, an oil component in coffee, was used as the extract component. In Example 6, the coating 40 was formed by immersion in a 1.05% citric acid solution for three minutes. In Example 7, the coating 40 was formed by immersion in a 6.3% citric acid solution for three minutes. In Example 8, the coating 40 was formed by immersion in a 1.05% citric acid solution heated to 97°C for three minutes. In the comparative example, no citric acid coating was formed. In the comparative example and examples, the diamond-like carbon layer 20 was not provided to obtain the effect of the coating 40 alone. The amount of attachment was calculated from the peak intensity of trioleic acid using Fourier transform infrared spectroscopy.

[0065] In Figure 10, the amount of adhesion is plotted on the vertical axis. The upper limit of the allowable range of the amount of adhesion is S. Compared to Example 6, Example 7, which had a higher concentration, had a smaller amount of adhesion. Therefore, the inventors of the present application discovered that the amount of adhesion can be further reduced by increasing the concentration of the citric acid solution. Furthermore, in Example 8, in which the citric acid solution was heated, the amount of adhesion was greater than in Example 6, in which the citric acid solution was not heated, but was below the maximum value S of the allowable range. This led the inventors of the present application to discover that the effect is also exhibited when the coating 40 is formed by heating the citric acid solution.

[0066] [Fifth Example] In Example 5, the contact angle of pure water W was measured when a coating 40 was formed on stainless steel by changing the citric acid concentration and immersion time. In Examples 9 to 12 and the Comparative Example, five samples were prepared under each set of conditions, and the average contact angle was calculated. Furthermore, to confirm the effect of the citric acid coating 40, no diamond-like carbon layer 20 was formed in Examples 9 to 12 and the Comparative Example. In Example 9, the sample was immersed in a solution with a citric acid concentration of 1.05% for 3 minutes. In Example 10, the sample was immersed in a solution with a citric acid concentration of 1.05% for 15 minutes. In Example 11, the sample was immersed in a solution with a citric acid concentration of 3.15% for 3 minutes. In Example 12, the sample was immersed in a solution with a citric acid concentration of 6.30% for 3 minutes. In the Comparative Example, no citric acid coating was formed.

[0067] As shown in Fig. 11, in Example 9, the contact angle θ1 was 67.9 degrees. As shown in Fig. 12, in Example 10, the contact angle θ2 was 62.7 degrees. As shown in Fig. 13, in Example 11, the contact angle θ3 was 48.0 degrees. As shown in Fig. 14, in Example 12, the contact angle θ4 was 42.1 degrees. As shown in Fig. 15, in the comparative example, the contact angle θ5 was 81.6 degrees.

[0068] In Examples 9 to 12, the contact angles were smaller than in the comparative example, demonstrating that forming a coating 40 using citric acid reduces the contact angle. Furthermore, since Example 10, which had a longer immersion time than Example 9, had a smaller contact angle, the inventors learned that a longer immersion time reduces the contact angle even at the same concentration. Examples 11 and 12, which had a higher citric acid concentration than Example 9, also had a smaller contact angle, and Example 12, which had a higher concentration than Example 11, also had a smaller contact angle. This indicated that a higher concentration can reduce the contact angle even at the same immersion time. From the above, the inventors learned that the contact angle can be reduced by at least one of increasing the concentration and increasing the immersion time. Furthermore, since Examples 11 and 12, which had a higher concentration than Example 10 but a shorter immersion time, had smaller contact angles, the inventors learned that increasing the concentration can reduce the contact angle even at a short immersion time.

[0069] FIG. 16 is a graph showing the relationship between contact angle and adhesion amount. The horizontal axis plots the contact angle, and the vertical axis plots the adhesion amount. The maximum value of the adhesion amount tolerance is S. From this graph, the inventors have learned that the contact angle that approaches the maximum value S of the adhesion amount tolerance is 80 degrees. The inventors have also learned that the adhesion amount decreases as the contact angle becomes smaller than 80 degrees. Therefore, the inventors have learned that the adhesion amount can be reduced by forming the coating 40.

[0070] The other configurations of the beverage brewing machine 200 of the second embodiment are similar to those of the beverage brewing machine 100 of the first embodiment.

[0071] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0072] In the second embodiment, as in the first embodiment, a diamond-like carbon layer 20 containing diamond-like carbon is provided in the portion 10 of at least one of the extraction unit 1 and the supply pipe 3 through which the extract passes. By forming the diamond-like carbon layer 20, adhesion of extract components can be suppressed. The inventors of the present application have learned this through experiments (examples) described below. Furthermore, because adhesion of extract components can be suppressed, the amount of extract component adhesion is reduced, making cleaning easier for the user. As a result, the burden of cleaning can be reduced.

[0073] Furthermore, in the second embodiment, as described above, a polybasic acid storage section 11 is provided in which a polybasic acid, which is a divalent or higher acid, is stored to be supplied to the extraction unit 1. The section 10 of the extraction unit 1 through which the extract passes and the section 10 of the supply pipe 3 through which the extract passes are washed with the polybasic acid, and a coating 40 of the polybasic acid is formed. By forming the coating 40 of the polybasic acid, the section 10 of the extraction unit 1 through which the extract passes and the section 10 of the supply pipe 3 through which the extract passes become hydrophilic, forming a water coating and preventing the adhesion of oily deposits. As a result, the section 10 through which the extract passes can be easily washed during cleaning, and components of the extract can be made less likely to adhere to the section 10 through which the extract passes after cleaning, making cleaning easier.

[0074] Furthermore, in the second embodiment, as described above, the polybasic acid is citric acid, and the device further includes a control unit 9 that controls the cleaning of the portion 10 of the extraction unit 1 through which the extract passes and the portion 10 of the supply pipe 3 through which the extract passes with citric acid and the formation of a citric acid coating. By forming a coating of citric acid, the portion 10 of the extraction unit 1 through which the extract passes and the portion 10 of the supply pipe 3 through which the extract passes become hydrophilic, forming a water coating and preventing oily deposits from adhering. The inventors of the present application have learned this through experiments (Examples) described below. Furthermore, because the cleaning and coating are performed by the control unit 9, unlike when the user performs the cleaning and coating, the user's effort can be reduced.

[0075] The other effects of the second embodiment are the same as those of the first embodiment.

[0076] [Third embodiment] The configuration of a beverage brewing machine 300 according to a third embodiment of the present invention will be described with reference to Figures 1 to 5, 17 and 18. In the figures, the same components as those in the beverage brewing machine 100 according to the first embodiment are designated by the same reference numerals.

[0077] As shown in FIG. 17 , in the third embodiment, a microstructure 60 is formed in the portion 10 of the extraction unit 1 and the supply pipe 3 through which the extract passes. The microstructure 60 has multiple lattices with a uniform lattice spacing. The lattices are configured to protrude from the surface, and the microstructure 60 has an uneven shape in which the lattices are convex and the adjacent lattices are concave in cross-sectional view. The lattice width and the depth of the concaves (height of the lattice) are uniform. While the example shows the lattices being perpendicular to the surface, they may be angled at 90 degrees or more relative to the surface to prevent components of the extract from entering. The presence of the microstructure 60 makes the portion 10 of the extraction unit 1 and the supply pipe 3 through which the extract passes water-repellent, making it difficult for components of the extract to adhere to them.

[0078] The microstructure 60 is formed by pressing a mold on which the microstructure 60 is formed against the extraction unit 1 and the portion 10 of the supply pipe 3 through which the extract passes, and transferring the microstructure 60. It is preferable that the microstructure 60 has a narrow lattice width (the width of the convex portions) and that the depth of the concave portions formed between the lattices is deep.

[0079] In the third embodiment, a diamond-like carbon layer 20 is formed on a surface on which a microstructure 60 is provided.

[0080] [Sixth Example] In the sixth example, the amount of adhesion of extract components was measured when the lattice width, lattice spacing, and recess length of the microstructure 60 were changed. Trioleic acid, an oil component in coffee, was used as the extract component. The amount of adhesion was calculated from the peak intensity of trioleic acid using Fourier transform infrared spectroscopy. The microstructure 60 was provided on a polyphenylene sulfide plate. In addition, in order to obtain the effect of the microstructure 60, the diamond-like carbon layer 20 was not provided.

[0081] [Table 1]

[0082] As shown in Table 1, in Example 13, the grating width was set to 50 μm, the grating interval was set to 105 μm, and the recess depth was set to 19 μm. In Example 14, the grating width was set to 50 μm, the grating interval was set to 300 μm, and the recess depth was set to 98 μm. In Example 15, the grating width was set to 300 μm, the grating interval was set to 300 μm, and the recess depth was set to 104 μm. In Example 16, the grating width was set to 50 μm, the grating interval was set to 300 μm, and the recess depth was set to 146 μm.

[0083] FIG. 18 shows the adhesion amounts when the microstructures 60 of Examples 13 to 16 were formed. The vertical axis plots the adhesion amount, with S representing the maximum value of the allowable range of adhesion amount. In all Examples, the adhesion amount was below the maximum allowable range, S. Furthermore, Example 15 had the highest adhesion amount, followed by Examples 13, 14, and 16 in that order. Since there was a large difference in adhesion amount between Examples 14 and 16, which differ only in the depth of the recesses, the present inventors discovered that the adhesion amount decreases as the recess depth increases. Furthermore, since the adhesion amounts differ between Examples 14 to 16, which have the same lattice spacing, the present inventors discovered that the lattice spacing does not significantly affect the adhesion amount. Furthermore, since the adhesion amount was smaller in Examples 13 and 14, which have a smaller depth than Example 15, the present inventors discovered that the adhesion amount can be reduced by narrowing the lattice width. This is thought to be due to the increased air space created by narrowing the lattice width and increasing the depth, which results in water repellency.

[0084] The other configurations of the beverage brewing machine 300 of the third embodiment are similar to those of the beverage brewing machine 100 of the first embodiment.

[0085] (Effects of the third embodiment) In the third embodiment, the following effects can be obtained.

[0086] In the third embodiment, as in the first embodiment, a diamond-like carbon layer 20 containing diamond-like carbon is provided in the portion 10 of at least one of the extraction unit 1 and the supply pipe 3 through which the extract passes. By forming the diamond-like carbon layer 20, adhesion of extract components can be suppressed. The inventors of the present application have learned this through experiments (examples) described below. Furthermore, because adhesion of extract components can be suppressed, the amount of extract component adhesion is reduced, making cleaning easier for the user. As a result, the burden of cleaning can be reduced.

[0087] The other effects of the third embodiment are the same as those of the first embodiment.

[0088] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0089] For example, in the first to third embodiments, examples have been shown in which a diamond-like carbon layer is provided on both the portion of the extraction section through which the extract passes and the portion of the supply pipe through which the extract passes, but the present invention is not limited to this. The present invention may also provide a diamond-like carbon layer on either the portion of the extraction section through which the extract passes or the portion of the supply pipe through which the extract passes, for example, the diamond-like carbon layer may be provided on the portion of the extraction section through which the extract passes.

[0090] In the first to third embodiments, diamond-like carbon layers are provided on both the portion of the extraction section through which the extract passes and the portion of the supply pipe through which the extract passes, but the present invention is not limited to this. In the present invention, diamond-like carbon layers may be provided on the filtration section (support section and metal mesh filter) in addition to the portion of the extraction section through which the extract passes and the portion of the supply pipe through which the extract passes.

[0091] In the first to third embodiments, the diamond-like carbon layer is formed by chemical vapor deposition, but the present invention is not limited to this. In the present invention, the diamond-like carbon layer may be formed by a method other than chemical vapor deposition. In this case, the diamond-like carbon layer may be formed by adhesion, for example.

[0092] Furthermore, in the first to third embodiments, the beverage brewing machine provides a coffee beverage, but the present invention is not limited to this. For example, the beverage brewing machine may provide a tea beverage. [Explanation of symbols]

[0093] 1 Extraction part 2 Filtration section 3 Supply pipe 9 Control Unit 11 Polybasic acid reservoir 20 Diamond-like carbon layer 30 Middle Class 40 Coating 50 Beverage containers 100, 200, 300 Beverage Brewing Equipment

Claims

1. an extraction unit to which the powdered raw material and the liquid are supplied and which extracts an extract; a filtration unit that filters the extract extracted by the extraction unit; a supply pipe for supplying the extract filtered by the filtration unit to a beverage container as a beverage, A beverage extraction device, wherein a diamond-like carbon layer containing diamond-like carbon is provided in a portion of at least one of the extraction section and the supply pipe through which the extract passes.

2. 2. The beverage extraction device according to claim 1, wherein at least one of the extraction unit and the supply pipe is formed from resin or metal, and the diamond-like carbon layer is provided on the surface of the portion through which the extract passes.

3. 3. The beverage extraction device according to claim 2, wherein at least one of the extraction unit and the supply pipe has an intermediate layer between the portion through which the extract passes and the diamond-like carbon layer, the intermediate layer improving adhesion between the diamond-like carbon layer and the portion through which the extract passes.

4. 2. The beverage extraction device according to claim 1, wherein the diamond-like carbon layer, which has a higher proportion of diamond structures than graphite structures, is provided in a portion of at least one of the extraction section and the supply pipe through which the extracted liquid passes.

5. a polybasic acid storage section for storing a polybasic acid, which is a divalent or higher acid, to be supplied to the extraction section; 2. The beverage extractor according to claim 1, wherein a portion of the extracting section through which the extract passes and a portion of the supply pipe through which the extract passes are cleaned with the polybasic acid and are coated with the polybasic acid.

6. the polybasic acid is citric acid; 6. The beverage extraction device according to claim 5, further comprising a control unit that controls cleaning of a portion of the extraction unit through which the extract passes and a portion of the supply pipe through which the extract passes with the citric acid and forming a coating of the citric acid.

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