Automatic analyzer and refrigerator

Abstract

To provide an automatic analyzer that suppresses the generation of mold by discharging or vaporizing dew condensation water generated on an inner surface of a refrigerator.SOLUTION: There is provided an automatic analyzer which includes a refrigerator that keeps a container that stores a reagent or analyte cool, in which a hydrophilic film having a contact angle with water of 15° or less is formed on the inner surface of the refrigerator, and which includes a dry air induction mechanism that introduces air with lower absolute humidity than the air in the refrigerator into the inner surface of the refrigerator. Since a predetermined hydrophilic film is formed on the inner surface of the refrigerator, the generated dew condensation water does not become water droplets and flows easily toward a drain route. In addition, the thin water film remaining on the hydrophilic film is quickly vaporized by the dry air introduced into the refrigerator.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an automatic analyzer, such as an immunoanalyzer or a biochemical analyzer, that mainly analyzes biological components, and a refrigerator provided in such an automatic analyzer. [Background technology]

[0002] The automated analyzer is equipped with a reagent refrigerator that stores reagents to be mixed with samples (specimens), and the inside of this reagent refrigerator is usually kept at a low temperature of about 5 to 10°C to prevent denaturation such as spoilage of the reagents. In addition, a reagent suction hole is provided in the lid that covers the top of the refrigerator so that a reagent dispensing nozzle can be inserted when aspirating the reagent from the reagent container inside the refrigerator. When outside air enters the refrigerator through this reagent suction hole, the outside air is cooled inside the reagent refrigerator, and the moisture in the outside air condenses to cause condensation.

[0003] For example, if the outside air temperature is 25°C and the relative humidity is 50%, the amount of saturated water vapor at 25°C is 23g / m 3 Therefore, the absolute humidity of the outside air is 11.5g / m 3 On the other hand, when the temperature inside the refrigerator is 5°C, the amount of saturated water vapor is 6.8g / m 3 Therefore, because the absolute humidity of the outside air exceeds the amount of saturated water vapor at 5°C, the water in the outside air that has entered the refrigerator that cannot dissolve in the air appears as condensation on the inside of the refrigerator.

[0004] Therefore, techniques for suppressing the generation of condensation water in a refrigerator have been proposed. For example, Patent Document 1 discloses an automatic analyzer that reduces or prevents the inflow of outside air from the reagent suction hole by raising the pressure inside the refrigerator to above atmospheric pressure by using cooling air (paragraph 0074). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-185980 A Summary of the Invention [Problem to be solved by the invention]

[0006] Even with the technology of Patent Document 1, when the lid is partially opened to replace the reagent container, the generation of condensation water due to the outside air flowing into the refrigerator is unavoidable. In addition, the condensation water that occurs is likely to form droplets on the inner surface of the refrigerator, and since the droplets are difficult to move from the inner surface unless multiple droplets combine to a certain size of about 5 mm, they do not flow toward the drainage path and continue to remain there, and if left unattended, mold may grow. Therefore, there is a limit to how often maintenance can be reduced.

[0007] An object of the present invention is to provide a refrigerator that can drain or volatilize condensation water that forms on the inner surface of the refrigerator, thereby suppressing the growth of mold, and an automatic analyzer equipped with the refrigerator. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides an automatic analyzer equipped with a refrigerator for keeping containers containing reagents or samples cool, in which a hydrophilic film having a contact angle with water of 15° or less is formed on the inner surface of the refrigerator, and a dry air introduction mechanism is provided for introducing air having an absolute humidity lower than that of the air inside the refrigerator into the inner surface of the refrigerator. Effect of the Invention

[0009] According to the present invention, since a predetermined hydrophilic film is formed on the inner surface of the refrigerator, the condensation water does not turn into droplets and easily flows toward the drainage path. In addition, the thin water film remaining on the hydrophilic film is quickly evaporated by the dry air introduced into the refrigerator. As a result, a refrigerator that suppresses the growth of mold and an automatic analyzer equipped with the refrigerator can be provided. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the overall configuration of an automatic analyzer according to an embodiment of the present invention. [Diagram 2]Top view of the reagent cooler (lid omitted). [Diagram 3] Cross-sectional side view of the reagent cooler. [Figure 4] Cross-sectional view of the chamber from the side. [Diagram 5] FIG. 4 is a cross-sectional view of the dry air introduction mechanism seen from the side. [Figure 6] Cross-section of a hydrophilic film observed with a scanning electron microscope. [Figure 7] 1 is a graph showing the relationship between the proportion of silicon dioxide particles in a hydrophilic film (solid content of a coating liquid) and the contact angle with water. [Figure 8] 1 is a graph showing the relationship between the percentage of silicon dioxide in a hydrophilic film (solid content of a coating liquid) and pencil hardness. [Figure 9A] FIG. 13 is a diagram showing the direction of spray when applying a coating liquid to the bottom surface of a chamber. [Figure 9B] FIG. 13 is a diagram showing the spray direction when applying a coating liquid to the outer peripheral side surface of a chamber. [Figure 9C] FIG. 13 is a diagram showing the spray direction when applying a coating liquid to the inner circumferential side surface of a chamber. [Figure 10] 1 is a graph showing the relationship between the thickness of a hydrophilic film and the contact angle with water. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, modes for carrying out the present invention (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings as appropriate.

[0012] (Overall configuration of the automatic analyzer) 1 is a diagram showing the overall configuration of an automatic analyzer according to this embodiment. The automatic analyzer 1 reacts a specimen sample with a reagent to analyze a specific component in the specimen, and mainly includes a rack transport line 7, an incubator disk 9, a sample dispensing tip / reaction vessel transport mechanism 14, a sample dispensing nozzle 10 (specimen dispensing mechanism), a reagent cooler 4, a reagent dispensing nozzle 11 (reagent dispensing mechanism), a reaction vessel stirring mechanism 16, a reaction vessel transport mechanism 12, and a detection unit 21.

[0013] The rack transport line 7 transports racks 6 on which sample containers 5 for accommodating samples are mounted, and can move the sample containers 5 to a sample dispensing position 13 in the vicinity of a sample dispensing nozzle 10 .

[0014] The incubator disk 9 is formed in a disk shape, and multiple reaction vessels 8 can be installed in the circumferential direction, and a predetermined reaction vessel 8 can be moved to a predetermined position by rotating it. A sample dispensing tip / reaction vessel transport mechanism 14 that transports the sample dispensing tip and the reaction vessel 8 is installed near the incubator disk 9.

[0015] The sample dispensing tip / reaction vessel transport mechanism 14 can move in three directions, the X-axis, the Y-axis, and the Z-axis, and can transport the sample dispensing tip and the reaction vessel 8 to each of the sample dispensing tip / reaction vessel holding section 15, the reaction vessel stirring mechanism 16, the sample dispensing tip / reaction vessel waste port 17, the sample dispensing tip mounting position 18, and a predetermined position on the incubator disk 9. Here, a plurality of unused reaction vessels 8 and sample dispensing tips are installed on the sample dispensing tip / reaction vessel holding section 15. The sample dispensing tip / reaction vessel transport mechanism 14 moves above the sample dispensing tip / reaction vessel holding section 15, descends to grab an unused reaction vessel 8, and then rises. The sample dispensing tip / reaction vessel transport mechanism 14 then moves above a predetermined position on the incubator disk 9, descends, and mounts an unused reaction vessel 8 on the incubator disk 9. Moreover, the sample dispensing tip / reaction vessel transport mechanism 14 moves above the sample dispensing tip / reaction vessel holder 15, then descends to grab an unused sample dispensing tip, and then ascends. Thereafter, the sample dispensing tip / reaction vessel transport mechanism 14 moves above the sample dispensing tip mounting position 18, then descends to place the sample dispensing tip at the sample dispensing tip mounting position 18.

[0016] The sample dispensing nozzle 10 can rotate and move up and down, and rotates and moves above the sample dispensing tip mounting position 18, then descends to mount the sample dispensing tip on the tip of the sample dispensing nozzle 10. The sample dispensing nozzle 10 with the sample dispensing tip mounted thereon then moves above the sample container 5 held in the rack 6, then descends to aspirate a predetermined amount of sample from the sample container 5. Next, the sample dispensing nozzle 10 that has aspirated the sample moves above the incubator disk 9, then descends to dispense the sample into an unused reaction container 8 held in the incubator disk 9. When the sample has been dispensed, the sample dispensing nozzle 10 discards the used sample dispensing tip from the sample dispensing tip / reaction container disposal port 17.

[0017] The reagent cooler 4 is for cooling and storing the reagent containers 2 that contain reagents, and includes a reagent container loading section 3 in which a plurality of reagent containers 2 are loaded, a chamber 22 that contains the reagent container loading section 3, and a lid 19 that enhances airtightness by covering the upper opening of the chamber 22. Furthermore, the lid 19 is provided with a reagent suction hole 20 that allows the reagent dispensing nozzle 11 to pass through, as well as a loader mechanism (not shown). The loader mechanism moves the reagent container loading section 3 up and down to load the reagent containers 2 into the reagent cooler 4 and load the reagent containers 2 out of the reagent cooler 4. Details of the reagent cooler 4 will be described later.

[0018] The reagent dispensing nozzle 11 can rotate and move up and down, and rotates to above a reagent suction hole 20 provided in the lid 19 of the reagent cooler 4, and then descends to pass through the reagent suction hole 20. The reagent dispensing nozzle 11 then puts its tip into the reagent in a predetermined reagent container 2 and aspirates a predetermined amount of reagent. After that, the reagent dispensing nozzle 11 rises and rotates to move above a predetermined position on the incubator disk 9, where it ejects the reagent into a reaction container 8 placed on the incubator disk 9. The reaction container 8 from which the sample and reagent have been ejected is moved to a predetermined position by the rotation of the incubator disk 9, and then transported to a reaction container stirring mechanism 16 by a sample dispensing tip / reaction container transport mechanism 14.

[0019] The reaction vessel stirring mechanism 16 applies a rotational motion to the reaction vessel 8 to stir and mix the sample and reagent in the reaction vessel 8. After stirring, the reaction vessel 8 is returned to a predetermined position on the incubator disk 9 by the sample dispensing tip / reaction vessel transport mechanism 14.

[0020] The reaction vessel transport mechanism 12 is capable of rotating and moving up and down, and moves above the reaction vessel 8 after the mixing of the sample and reagent is completed and a predetermined reaction time has elapsed on the incubator disk 9, and then moves down to hold the reaction vessel 8. The reaction vessel transport mechanism 12 then rotates and transports the reaction vessel 8 to the detection unit 21.

[0021] The detection unit 21 performs qualitative / quantitative analysis of a specific component contained in the sample in the transported reaction vessel 8. The display of the analysis results and the control of each mechanism are performed by a control computer (not shown).

[0022] (Configuration of Reagent Cooler) Next, the configuration of the reagent refrigerator 4 will be described in detail with reference to Figures 2 and 3. The following description will be given taking a reagent refrigerator that keeps reagents cool as an example, but the same can be applied to a specimen refrigerator that keeps specimens cool. Figure 2 is a top view of the reagent refrigerator (lid omitted), and Figure 3 is a cross-sectional view of the reagent refrigerator from the side. The reagent refrigerator 4 has the reagent container loading section 3, lid 19, and chamber 22 described above, as well as a cooling mechanism 26 and a dry air introduction mechanism 33.

[0023] The reagent container loading unit 3 is held within the chamber 22 when the automatic analyzer is in operation, and can be rotated together with the chamber 22 by a movable shaft 25 via a central adapter 24, as necessary. When a specific reagent is dispensed, the reagent container 2 containing the specific reagent is positioned below the vertical projection of the reagent suction hole 20 due to the rotation of the reagent container loading unit 3. Although not shown in the figure, a motor for rotating the movable shaft 25 is provided at the lower end of the movable shaft 25.

[0024] In addition to the reagent suction hole 20 described above, the lid 19 is formed with an opening through which the reagent container loading unit 3 passes when the reagent container 2 is carried in and out, and is also provided with an opening / closing lid 23 for opening and closing this opening. When the reagent inside the reagent container 2 loaded in the reagent container loading unit 3 becomes low on reagent or becomes empty, the reagent container loading unit 3 is lifted by a loader mechanism (not shown) and carried out to the outside of the reagent cooler 4. Thereafter, the used reagent container 2 is removed from the reagent container loading unit 3, and an unused reagent container 2 is loaded into the reagent container loading unit 3.

[0025] The chamber 22 is disposed so as to surround the periphery and bottom of the reagent container loading section 3, and together with the lid 19 and the opening / closing lid 23, defines a cold storage space for cooling and storing the reagent containers 2. The cold storage space is cooled by a cooling mechanism 26. A housing 27 is provided on the outside of the chamber 22 with a heat insulating material 28 interposed therebetween to improve cooling efficiency.

[0026] The cooling mechanism 26 is disposed below the chamber 22 and serves to cool the chamber 22, and is desirably configured with a small device such as a Peltier element. By using a metal with high thermal conductivity such as copper or aluminum as the material for the chamber 22, the chamber 22 can be efficiently cooled by the cooling mechanism 26.

[0027] Here, since the lid 19 is provided with the reagent suction hole 20 through which the reagent dispensing nozzle 11 passes and the opening through which the reagent container loading section 3 passes, it is unavoidable that outside air will enter the cold storage space, and the moisture contained in the outside air will condense on the inner surface of the chamber 22. Therefore, the bottom surface of the chamber 22 is provided with a drain 31 for draining the condensed water, and, if necessary, a slope that descends toward the drain 31.

[0028] Furthermore, in this embodiment, a hydrophilic film 32 is formed on the inner surface of the chamber 22 to facilitate the flow of condensed water toward the drain groove 31. FIG. 4 is a cross-sectional view of the chamber from the side. If the inner surface of the chamber 22 were not formed of a hydrophilic film, the condensed water would become droplets and adhere to the inner surface of the chamber 22, and would not flow toward the drain groove 31 unless it reached a certain size (approximately 5 mm in diameter or more). In contrast, in this embodiment, the hydrophilic film 32 having a contact angle with water of 15° or less is formed on the inner surface of the chamber 22, so that the condensed water on the hydrophilic film 32 becomes a water film. The water film flows along the inner surface of the chamber 22, and as a result, 90% or more of the condensed water is discharged from the drain groove 31.

[0029] However, some of the condensed water is not discharged from drain 31 and remains as a water film on the inner surface of chamber 22. Therefore, reagent refrigerator 4 of this embodiment not only forms a hydrophilic film on the inner surface of chamber 22, but also has dry air introduction mechanism 33 that introduces dry air into chamber 22, and quickly volatilizes the water film remaining on the inner surface. This makes it possible to suppress the growth of mold on the inner surface of chamber 22.

[0030] Fig. 5 is a cross-sectional view of the dry air introduction mechanism as viewed from the side. The purpose of the dry air introduced by dry air introduction mechanism 33 into reagent cooler 4 (specifically chamber 22) is to dry condensed water inside reagent cooler 4, and so the absolute humidity of the dry air needs to be lower than the absolute humidity of the air inside reagent cooler 4. As shown in Fig. 5, dry air introduction mechanism 33 mainly includes fan 35, filter 36, aluminum fins 40, aluminum fin holder 38, heat exchanger 37, piping 39, and gutter 41.

[0031] The fan 35 is driven (rotated) when taking in the outside air 34 into the reagent cooler 4 (dry air introduction mechanism 33), and the filter 36 removes dust particles such as dirt from the outside air. The aluminum fins 40 come into contact with the outside air 34 that has passed through the filter 36 to cool the outside air 34, and the aluminum fin holder 38 holds the aluminum fins 40. The heat exchanger 37 supplies the cooled refrigerant into the piping 39. The piping 39 is made of aluminum and is provided so as to penetrate the aluminum fin holder 38 at multiple points, so that the aluminum fin holder 38 and the aluminum fins 40 are cooled by the refrigerant supplied from the heat exchanger 37. The gutter 41 is formed with an incline so as to descend toward the drain 31, and when condensation water generated on the aluminum fins 40 due to contact with the outside air 34 flows down, it plays a role of receiving the condensation water and directing it to the drain 31.

[0032] A portion of the dry air that has passed through the dry air introduction mechanism 33 (aluminum fins 40) is discharged from the drain groove 31 to the outside of the refrigerator, while the remainder is supplied up the drain groove 31 into the chamber 22. The dry air supplied into the chamber 22 volatilizes the water film on the surface of the hydrophilic film 32, so that the inner surface of the chamber 22 is dried and the growth of mold is suppressed. In addition, the introduction of the dry air creates a positive pressure inside the chamber 22, so that the amount of outside air entering through the reagent suction hole 20 and the opening (opening / closing lid 23) is reduced, and condensation itself is suppressed. Note that the configuration of the dry air introduction mechanism 33 shown in FIG. 5 is merely an example, and other configurations may be used.

[0033] (hydrophilic film) <Summary> As described above, the reagent cooler 4 in the automatic analyzer of this embodiment has a hydrophilic film 32 formed on the inner surface of the chamber 22, and the contact angle of the hydrophilic film 32 with water is 15° or less. In the case of a hydrophilic film with a contact angle with water of more than 15°, condensed water is less likely to become a water film, and is therefore less likely to be discharged from the drain 31, and is more likely to remain without volatilizing even when dry air is introduced. In addition, it is desirable that the hydrophilic film 32 formed on the inner surface of the chamber 22 is not only highly water-resistant, but also has high hardness so that it is less likely to be scratched even when it comes into contact with the reagent container loading section 3, the reagent container 2, etc. Therefore, in this embodiment, the hydrophilic film 32 is formed using silicon dioxide particles and a binder.

[0034] FIG. 6 is a cross-sectional view of a hydrophilic film observed by a scanning electron microscope. According to FIG. 6, silicon dioxide particles 43 and voids 44 constituting the hydrophilic film can be confirmed on a substrate 42. Although not confirmed in FIG. 6, silicon dioxide binder is also present between the silicon dioxide particles 43 and on the surface of the substrate 42, and the structure of the film is maintained. The contact angle with water of silicon dioxide itself is about 30°, but the contact angle with water is reduced due to the fine unevenness of the silicon dioxide particles 43 on the surface of the hydrophilic film. In addition, the contact angle with water is further reduced by the condensed water seeping into the voids 44 inside the hydrophilic film due to the capillary phenomenon. As a result, a hydrophilic film with a contact angle with water of 15° or less is realized.

[0035] Here, since the shape of the chamber 22 is complicated as shown in Fig. 4, it is preferable to apply the coating liquid for forming the hydrophilic film by a spray coating method, rather than a dip coating method, spin coating method, etc. After the coating liquid is applied, the binder precursor contained in the coating liquid is thermally cured to form a binder, and the hydrophilic film is formed.

[0036] <Composition of the coating solution that forms the hydrophilic film> The coating liquid is prepared by dispersing and dissolving silicon dioxide particles and a precursor of a silicon dioxide binder in an alcohol-based organic solvent. Details of each material and the mixing ratio of the materials are described below.

[0037] <Silicon dioxide particles> Silicon dioxide particles with an average particle size of about 5 to 50 nm are used. If the particle size is smaller than this, it will tend to float in the air as dust when preparing the coating liquid. Also, as the particle size becomes smaller, the surface area per unit weight becomes larger, making it more likely to become charged. Especially in winter, it will tend to adhere to walls at manufacturing sites. Therefore, from the viewpoint of ease of handling, the lower limit of the particle size is 5 nm. Taking into account the particle size distribution, the lower limit of the average particle size is preferably 10 nm.

[0038] On the other hand, when the particle size is large, the coating liquid becomes easier to handle when it is prepared, but the number of voids between the particles after film formation is reduced, so hydrophilicity tends to decrease. In addition, in a coating liquid prepared using silicon dioxide particles with a particle size of 5 to 50 nm, the silicon dioxide particles hardly settle even when stored for a long period of time, but when silicon dioxide particles with a larger particle size are used, the silicon dioxide particles settle at the bottom of the coating liquid when stored for a long period of time. The density of silicon dioxide is originally about 2.5, which is larger than that of general-purpose organic solvents with a density of about 0.7 to 1.1, so silicon dioxide with a large particle size will sink, but silicon dioxide with a small particle size is suppressed from settling due to interactions such as collisions with solvent molecules. Due to this effect, if the particle size is up to about 50 nm, settling is suppressed, and if it is larger than that, settling will occur. Considering the distribution of particle size, the upper limit of the average particle size is preferably 30 nm.

[0039] In summary, the average particle size of the silicon dioxide particles used in the coating liquid is preferably 5 nm or more and 50 nm or less, more preferably 10 nm or more and 30 nm or less. Some particles are made up of several to several dozen particles with a size of 10 nm or more and 30 nm or less, and even in such cases, they are preferable because they are unlikely to settle in the solvent.

[0040] <Silicon dioxide binder precursor> Silicon dioxide is insoluble in organic solvents, but some of its precursors are soluble in organic solvents. In this embodiment, a precursor of silicon dioxide that dissolves in organic solvents is used. Specifically, a hydrolyzable silicon compound that changes to silicon dioxide by hydrolysis is used. The most common hydrolyzable silicon compound is usually called silica sol. Silica sol is a polymer in which a plurality of tetraalkoxysilanes are partially hydrolyzed, alkoxy groups are removed, and a plurality of molecules form silicon-oxygen-silicon bonds with each other, resulting in an average molecular weight of several thousand to several tens of thousands. Silica sol is soluble in alcohol-based solvents such as methanol and ethanol. As the tetraalkoxysilane, tetraethoxysilane is the easiest to use. Tetramethoxysilane, which has a shorter alkyl chain than this, is highly reactive with water, so if it is stored for a long period of time in a high humidity environment, the coating liquid that forms the hydrophilic film may solidify. In addition, tetrapropoxysilane and tetrabutoxysilane, which have longer alkyl chains than tetraethoxysilane, are less likely to undergo hydrolysis, so the heat curing time after application tends to be longer, and the heat curing reaction tends to proceed slowly unless the heating temperature is high. Therefore, the tetraalkoxysilane used to form the silica sol is preferably tetraethoxysilane.

[0041] In addition to silica sol, a compound having a silicon atom with four bonding groups in the molecule, three alkoxy groups, and other bonding groups other than alkoxy groups such as a benzene ring or an alkyl chain can also be used as a precursor for the silicon dioxide binder. However, when this material is used, the hydrophilic film will contain not only silicon dioxide but also atoms such as carbon, nitrogen, and sulfur.

[0042] Specific examples of the compound include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

[0043] <Organic solvent> As the solvent for the coating liquid, it is preferable to use one in which the precursor of the silicon dioxide binder can be dissolved. In this respect, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, etc. are preferable. In pentanol, hexanol, octanol, etc., which have a longer hydrocarbon chain than this, the precursor of the silicon dioxide binder becomes difficult to dissolve, and in some cases, it may become partially separated. In addition, since the boiling point is high when the hydrocarbon chain is long, there is a possibility that dripping may occur after application, so the number of carbon atoms of the alcohol is preferably 4 or less, that is, the upper limit is butanol. In addition, the precursor of the silicon dioxide binder is also easily dissolved in diols such as ethylene glycol and diethylene glycol. However, diols have a higher boiling point than alcohols such as ethanol and butanol, and take a long time to dry after application, so they are not practical solvents.

[0044] ≪Mixing ratio≫ The hydrophilic film is formed by the solid content in the coating liquid, that is, silicon dioxide particles and a precursor of the silicon dioxide binder. Here, when applying to the inner surface of the chamber 22 by spray coating, if the coating liquid has a high solid content ratio, the nozzle is likely to be clogged, and even if it is not clogged, the solid content may accumulate near the nozzle and change the direction of the spray. For this reason, it is preferable that the concentration of the solid content in the coating liquid is at most 1% by weight, and that a coating liquid with a higher concentration is not used. In other words, the ratio of the organic solvent in the coating liquid that forms the hydrophilic film is preferably 99% by weight or more.

[0045] The contact angle of the hydrophilic film with water can be changed by the mixing ratio of two materials, silicon dioxide particles and the precursor of the silicon dioxide binder. This is because the source of hydrophilicity is silicon dioxide particles, and the higher the ratio of silicon dioxide particles, the lower the contact angle with water tends to be.

[0046] Fig. 7 is a graph showing the relationship between the ratio of silicon dioxide particles in the hydrophilic film (solid content of the coating liquid) and the contact angle with water. Note that Fig. 7 shows an example in which the particle diameter of the silicon dioxide particles is 10 nm, the heat curing time after spray coating of the coating liquid is 1 hour, the heat curing temperature is 180°C, and the film thickness of the hydrophilic film is 100 nm.

[0047] As shown in FIG. 7, when the proportion of silicon dioxide particles in the solid content of the coating liquid was 20% by weight or more, the contact angle of the formed hydrophilic film with water was less than 10°. When the proportion of silicon dioxide particles was smaller than this, the contact angle of the hydrophilic film with water was larger than 10°. Specifically, when the proportion of silicon dioxide particles was 15% by weight, the contact angle of the hydrophilic film with water increased to about 15°. Similarly, when the proportion of silicon dioxide particles was 12% by weight, the contact angle of the hydrophilic film with water increased to about 20°. Furthermore, when the proportion of silicon dioxide particles was zero, the contact angle of the hydrophilic film with water was about 32°.

[0048] Fig. 8 is a graph showing the relationship between the ratio of silicon dioxide in the hydrophilic film (solid content of the coating liquid) and pencil hardness. As with Fig. 7, Fig. 8 shows an example in which the particle diameter of the silicon dioxide particles is 10 nm, the heat curing time after spray coating of the coating liquid is 1 hour, the heat curing temperature is 180°C, and the thickness of the hydrophilic film is 100 nm.

[0049] As shown in FIG. 8, when the ratio of silicon dioxide particles was increased, that is, when the ratio of the precursor of the silicon dioxide binder was decreased, the physical strength of the hydrophilic film was decreased. When the ratio of silicon dioxide particles was 80% by weight, the pencil hardness of the hydrophilic film was about 2H. This level of hardness is considered to be no problem in practical use. However, when the ratio of silicon dioxide particles was 85% by weight, the pencil hardness of the hydrophilic film was reduced to about 2B. Assuming that the material of the reagent container 2, etc. is an acrylic or polyethylene terephthalate resin, the pencil hardness of these resins is about 2B to H, so if the reagent container 2, etc., is accidentally dropped on the hydrophilic film, the hydrophilic film may be scratched. Therefore, it is preferable that the ratio of silicon dioxide particles in the solid content of the coating liquid forming the hydrophilic film is 80% by weight or less, in other words, the ratio of the precursor of the silicon dioxide binder is 20% by weight or more.

[0050] Considering both the contact angle with water and the pencil hardness described above, the proportion of silicon dioxide particles in the solid content of the coating liquid that forms the hydrophilic film is preferably 15% by weight or more and 80% by weight or less, and more preferably 20% by weight or more and 80% by weight or less.

[0051] <Film formation method> As described above, spray coating is suitable for applying a coating liquid to the inner surface of the chamber 22 having a complex shape. Here, a method for applying a coating liquid to the inner surface of the chamber 22 by spray coating will be specifically described with reference to Figures 9A to 9C.

[0052] When applying the coating liquid to a bottom surface 46 of the chamber 22, as shown in Fig. 9A, the spray gun 45 discharges droplets 47 of the coating liquid from directly above the bottom surface of the chamber 22. Next, when applying the coating liquid to an outer peripheral side surface 48 of the chamber 22, as shown in Fig. 9B, the spray gun 45 discharges droplets 47 of the coating liquid while being tilted slightly toward the outer periphery. Furthermore, when applying the coating liquid to an inner peripheral side surface 49 of the chamber 22, as shown in Fig. 9C, the spray gun 45 discharges droplets 47 of the coating liquid while being tilted slightly toward the inner periphery.

[0053] In any of the cases of FIG. 9A to FIG. 9C, the spray gun 45 applies droplets 47 of the coating liquid to one side of the axis of the chamber 22 while rotating the chamber 22 on a table (not shown), so that the coating liquid can be applied to the entire inner surface of the chamber 22 with a uniform thickness. The smaller the size of the droplets 47, the easier it is to control the film thickness uniformly, but the time required for application increases, so if the droplets are too small, the throughput during mass production tends to decrease. In addition, in order to reduce the size of the droplets 47, the nozzle diameter of the spray gun 45 needs to be reduced, and in that case, the solid content in the coating liquid is likely to clog the nozzle tip or its vicinity. Therefore, the size of the droplets 47 is preferably about 10 to 100 μm, more preferably 10 to 50 nm.

[0054] Next, the results of an investigation into the thickness of the hydrophilic film required to obtain sufficient hydrophilicity will be described. Fig. 10 is a graph showing the relationship between the thickness of the hydrophilic film and the contact angle with water. Fig. 10 shows an example in which the particle diameter of the silicon dioxide particles is 10 nm, the ratio of the silicon dioxide particles to the solid content in the coating liquid forming the hydrophilic film is 50% by weight, the heat curing time after spray coating the coating liquid is 1 hour, and the heat curing temperature is 180°C.

[0055] As shown in FIG. 10, when the thickness of the hydrophilic film was 50 nm or more, the contact angle with water was about 5°. It was also found that a film thickness of 40 nm or more was required to obtain a hydrophilic film with a contact angle with water of 15° or less. The lower the contact angle with water, the thinner the water film of condensed water becomes, so a contact angle of 5° is preferable to 15°. In other words, the thickness of the hydrophilic film is preferably 50 nm or more. The reason why the contact angle becomes higher when the hydrophilic film is thin is presumed to be because the gaps between the particles become shallower and the capillary phenomenon becomes weaker.

[0056] In fact, when a hydrophilic film was formed by applying the coating liquid to the chamber 22 with a spray gun, the film thickness varied by about ±30 to 50%. This is thought to be due to the complex shape of the chamber 22. That is, even if an average film thickness of 50 nm is aimed for, the thinnest part may be as thin as about 25 nm. Therefore, taking the film thickness variation into consideration, it is preferable to aim for an average film thickness of the hydrophilic film to be 100 nm or more.

[0057] The present invention will be described below with reference to examples and comparative examples. EXAMPLES

[0058] (Preparation of Coating Solution) First, silicon dioxide particles (15 g) with an average particle size of 10 nm, diethylene glycol monoacetate (0.5 g), and ethanol (84.5 g) are placed in a polypropylene bottle with a capacity of 200 ml, and these are stirred with an overhead stirrer to prepare 100 g of a dispersion A of 15 wt% silicon dioxide particles. Next, 750 g of silica sol solution B is prepared so that the solid content concentration after hydrolysis is 2 wt%. Then, dispersion solution A (1 g), silica sol solution B (7.5 g), and Solmix AP-7 (291.5 g), an industrial ethanol manufactured by Japan Alcohol Sales Co., Ltd., are added to a polypropylene bottle with a capacity of 1000 ml, and the bottle is sealed and stirred several times to prepare a coating solution (hydrophilic coating solution C) (300 g) with a solid content of 0.1 wt% and in which silicon dioxide particles form a hydrophilic film that accounts for 50 wt% of the solid content. The contact angle of the hydrophilic film formed using the hydrophilic coating solution C prepared in this example with water was 5°.

[0059] (Hydrophilic film deposition process on chamber) The chamber used in this embodiment has a diameter of 61 cm, a height of the outer peripheral side of 14 cm, and a raised part of 14 cm in diameter and 9 cm in height on the inner peripheral side (center), so the total area of ​​the inner surface is about 6000 cm2. The hydrophilic film is made of silicon dioxide with a density of about 2.5 g / cm3, but since it has voids inside, it is actually estimated to be about 1.5 g / cm3. To form a film with an average thickness of 100 nm, if the density of the film is assumed to be 1.5, the solid content of the film will be 0.09 g, and the weight of the hydrophilic coating liquid C with this solid content will be 90 g. During spray coating, the hydrophilic coating liquid C will scatter outside the chamber, so the utilization efficiency of the hydrophilic coating liquid C is estimated to be about 50%. Therefore, to form a hydrophilic film with an average thickness of 100 nm on the inner surface of the chamber, about 180 g of hydrophilic coating liquid C is required.

[0060] Therefore, in this embodiment, taking into consideration a margin, 250 g of hydrophilic coating liquid C was placed in the paint filling container of the spray gun. Then, as shown in Figs. 9A to 9C, the hydrophilic coating liquid C was applied to the chamber. After application, the chamber was placed in a thermostatic chamber at 180°C and heated for 1 hour. After heating, the chamber was removed from the thermostatic chamber and left to stand until the surface reached the temperature of human skin. In this way, a chamber having a hydrophilic film on the inner surface was formed.

[0061] (Verification using a refrigerator with a built-in chamber (automatic analyzer)) The chamber on which the hydrophilic film was formed as described above was attached to the reagent cooler of Hitachi High-Technologies Corporation's immunological autoanalyzer e-801. Next, the inside of the reagent cooler was cooled until the temperature inside the reagent container reached 5°C, after which a reagent container loading section was installed in the chamber and the reagent container was inserted into it. Then, the autoanalyzer was operated, and the reagent sucked from each reagent container was discharged into a reaction container containing a sample, and a specific component contained in the sample was qualitatively / quantitatively analyzed by a color reaction or a luminescence reaction or the like. During operation of the autoanalyzer, dry air was constantly introduced into the reagent cooler by the dry air introduction mechanism shown in Figure 5, and the inside of the reagent cooler was kept at a positive pressure of about 0.001 atm from the outside of the chamber. Then, the autoanalyzer was operated for two weeks while the inside of the reagent cooler was maintained at 5°C, and the inner surface of the chamber was observed. The inner surface of the chamber was found to be almost dry, and no mold was found to have grown.

[0062] On the other hand, a chamber without a hydrophilic film was also installed in the reagent cooler of Hitachi High-Tech's automated immunoanalyzer e-801 and operated for two weeks under the same conditions as above. The inner surface of the chamber was then observed. The inner surface of the chamber was found to be wet with water droplets due to condensation, and mold was found in some areas.

[0063] From the above, it became clear that by forming a hydrophilic film with a contact angle of 5° with water on the inner surface of the chamber, it is possible to suppress the growth of mold even when the automatic analyzer is operated for a relatively long period of time. EXAMPLES

[0064] In Example 2, unlike Example 1, when preparing the coating solution, dispersion A (0.4 g), silica sol solution B (7.5 g), and Solmix AP-7 (287.6 g), an industrial ethanol manufactured by Japan Alcohol Sales Co., Ltd., were added to a polypropylene bottle with a capacity of 1000 ml, and the bottle was sealed and stirred several times to prepare a coating solution (hydrophilic coating solution D) (300 g) that forms a hydrophilic film with a solid content of 0.1 wt % and silicon dioxide particles accounting for 20 wt % of the solid content. The contact angle of the hydrophilic film formed using the hydrophilic coating solution D prepared in Example 2 with water was 8°. The other conditions were the same as those in Example 1.

[0065] The chamber with the hydrophilic film formed was attached to a reagent refrigerator and the automatic analyzer was operated for two weeks. When the inside of the reagent refrigerator was then observed, the inner surface of the chamber was found to be almost dry, with no signs of mold growth.

[0066] From the above, it became clear that by forming a hydrophilic film with a contact angle of 8° with water on the inner surface of the chamber, it is possible to suppress the growth of mold even when the automatic analyzer is operated for a relatively long period of time. EXAMPLES

[0067] In Example 3, unlike Example 1 and Example 2, when preparing the coating solution, dispersion A (0.4 g), silica sol solution B (17 g), and Solmix AP-7 (382.6 g), an industrial ethanol manufactured by Japan Alcohol Sales Co., Ltd., were added to a polypropylene bottle with a capacity of 1000 ml, and the bottle was sealed and stirred several times to prepare a coating solution (hydrophilic coating solution E) (400 g) that forms a hydrophilic film with a solid content of 0.1 wt % and silicon dioxide particles accounting for 15 wt % of the solid content. The contact angle of the hydrophilic film formed using the hydrophilic coating solution E prepared in Example 3 with water was 15°. Other conditions were the same as those of Example 1 and Example 2.

[0068] The chamber with the hydrophilic film formed was attached to a reagent refrigerator and the automatic analyzer was operated for two weeks. When the inside of the reagent refrigerator was then observed, the inner surface of the chamber was found to be almost dry, with no signs of mold growth.

[0069] From the above, it became clear that by forming a hydrophilic film with a contact angle of 15° with water on the inner surface of the chamber, it is possible to suppress the growth of mold even when the automatic analyzer is operated for a relatively long period of time.

[0070] Comparative Example 1 In Comparative Example 1, unlike the Examples, when preparing the coating solution, dispersion A (0.2 g), silica sol solution B (11 g), and Solmix AP-7 (238.8 g), an industrial ethanol manufactured by Japan Alcohol Sales Co., Ltd., were added to a polypropylene bottle with a capacity of 1000 ml, and the bottle was sealed and stirred several times to prepare a coating solution (hydrophilic coating solution F) (250 g) that forms a hydrophilic film with a solid content of 0.1 wt % and silicon dioxide particles of 12 wt % of the solid content. The contact angle with water of the hydrophilic film formed using the hydrophilic coating solution F prepared in Comparative Example 1 was 20°. Other conditions were the same as those in the Examples.

[0071] The chamber with the hydrophilic film formed was attached to a reagent refrigerator and the automatic analyzer was operated for two weeks. When the inside of the reagent refrigerator was observed after that, no mold was found on the inner surface of the chamber, but a water film was found to have adhered in places.

[0072] From the above, it was found that when the contact angle of the hydrophilic film formed on the inner surface of the chamber with water is 20°, the condensed water cannot be completely removed. Furthermore, when the automatic analyzer was continued to operate for another four weeks, black mold began to grow on some of the water film that had been adhering in places.

[0073] Considering the examples and comparative example 1, it can be determined that if the contact angle of the hydrophilic film formed on the inner surface of the chamber with water exceeds 15°, it may not be possible to suppress the growth of mold caused by condensed water. This is thought to be because, as the contact angle with water increases, the water film becomes thicker and the amount of condensed water adhering to the inner surface of the chamber increases. Therefore, in order to reliably drain the condensed water generated on the inner surface of the cooler, it is important to form a hydrophilic film with a contact angle with water of 15° or less on the inner surface of the cooler chamber.

[0074] Comparative Example 2 In Comparative Example 2, unlike the embodiment, the dry air introduction mechanism was stopped so that dry air was not introduced into the reagent refrigerator. The other conditions were the same as those in Example 1.

[0075] After two weeks of operation of the automated analyzer, the inside of the reagent refrigerator was observed and found to have no mold on the inner surface of the chamber, and the area far from the drain was dry, but the area close to the drain was covered with a water film. Furthermore, when the amount of water flowing out of the drain was examined, it was found that most of the condensation water was discharged from the drain.

[0076] From the above, it was found that if dry air is not introduced into the refrigerator, the condensation water remains as a small water film on the inside of the refrigerator, and the condensation water cannot be completely removed. In addition, when the automatic analyzer was continued to operate for another four weeks, black mold began to grow on part of the water film that was attached to the part near the drain.

[0077] Considering the Example and Comparative Example 2, it can be said that it is important to introduce dry air into the inner surface of the cooler in order to reliably volatilize the condensation water that forms on the inner surface of the cooler.

[0078] Comparative Example 3 In Comparative Example 3, unlike the embodiment, only the function of drying the outside air in the dry air introduction mechanism was stopped, and normal outside air, not dry air, was introduced into the reagent refrigerator. The other conditions were the same as those in Example 1.

[0079] After operating the automatic analyzer for two weeks, the inside of the reagent refrigerator was observed and no mold was found on the inside of the chamber, but the area near the drain was covered with a water film. The area covered with the water film was larger than that of the comparative example. Furthermore, when the amount of water flowing out of the drain was examined, it was found that most of the condensation water was discharged from the drain.

[0080] From the above, it was found that if the air introduced into the refrigerator is not dry, the condensation water remains as a water film on the inside of the refrigerator and cannot be completely removed. In addition, when the automatic analyzer was continued to operate for another two weeks, black mold began to grow on part of the water film that was attached to the part near the drain.

[0081] Considering the Example and Comparative Example 3, it can be said that in order to reliably evaporate the condensation water that forms on the inner surface of the cooler, it is important to introduce dry air, rather than outside air, into the inner surface of the cooler. [Explanation of symbols]

[0082] 1...automatic analyzer, 2...reagent container, 3...reagent container loading section, 4...reagent cooler, 5...sample container, 6...rack, 7...rack transport line, 8...reaction container, 9...incubator disk, 10...sample dispensing nozzle, 11...reagent dispensing nozzle, 12...reaction container transport mechanism, 13...sample dispensing position, 14...sample dispensing tip / reaction container transport mechanism, 15...sample dispensing tip / reaction container holder, 16...reaction container stirring mechanism, 17...sample dispensing tip / reaction container waste port, 18...sample dispensing tip mounting position, 19...lid, 20...reagent suction hole, 21...detection unit, 22...chamber, 23...opening / closing cover, 24...adapter, 25...moving shaft, 26...cooling mechanism, 27...casing, 28...insulating material, 30...condensation water, 31...drain, 32...hydrophilic film, 33...dry air introduction mechanism, 34...outside air, 35...fan, 36...filter, 37...heat exchanger, 38...aluminum fin holder, 39...piping, 40...aluminum fin, 41...gutter, 42...base material, 43...silicon dioxide particles, 44...gap, 45...spray gun, 46...bottom, 47...droplets, 48...outer periphery, 49...inner periphery

Claims

1. In an automatic analyzer equipped with a refrigerator for cooling containers containing reagents or specimens, A hydrophilic film having a contact angle with water of 15° or less is formed on the inner surface of the refrigerator, An automatic analyzer having a dry air introduction mechanism that introduces air having an absolute humidity lower than that of the air inside the refrigerator into an inner surface of the refrigerator.

2. In claim 1, The automated analyzer, wherein the hydrophilic membrane comprises silicon dioxide.

3. In claim 2, An automatic analyzer, wherein the proportion of silicon dioxide in the hydrophilic film is 20% by weight or more and 80% by weight or less.

4. In claim 2, The hydrophilic membrane has voids between the silicon dioxide particles.

5. In claim 4, An automatic analyzer, wherein the average particle size of the silicon dioxide in the hydrophilic film is 10 nm or more and 30 nm or less.

6. In claim 1, The average thickness of the hydrophilic film is 100 nm or more.

7. In a cool storage facility that keeps stored items cool, A hydrophilic film having a contact angle with water of 15° or less is formed on the inner surface of the refrigerator, The cool storage has a dry air introduction mechanism that introduces air having a lower absolute humidity than the air inside the cool storage into an inner surface of the cool storage.

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