Automatic analyzer and cold storage unit

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 mainly for analyzing biological components such as an immunoassay apparatus and a biochemical analyzer, and a refrigerator provided in an automatic analyzer or the like.

Background Art

[0002] An automatic analyzer includes a reagent refrigerator for storing reagents to be mixed with a sample (specimen). The inside of this reagent refrigerator is usually kept at a low temperature of about 5 to 10°C in order to suppress denaturation such as spoilage of the reagents. Further, a reagent suction hole is provided in a lid that covers the upper part of the refrigerator so that a reagent dispensing nozzle can be inserted when sucking the reagent from a reagent container in the refrigerator. When outside air enters the refrigerator through this reagent suction hole, the outside air is cooled in the reagent refrigerator, and moisture in the outside air condenses to cause dew condensation.

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

[0004] Therefore, technologies for suppressing dew condensation in the refrigerator have been proposed conventionally. For example, Patent Document 1 discloses an automatic analyzer that reduces or prevents the inflow of outside air from a reagent suction hole by making the inside of the refrigerator higher than atmospheric pressure with cooling air (paragraph 0074).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] Even with the technology described in Patent Document 1, when a portion of the lid is opened to replace a reagent container, condensation due to outside air flowing into the refrigerator is unavoidable. Furthermore, the condensed water easily turns into droplets on the inside of the refrigerator, and since these droplets are difficult to move from the inside unless they combine to a certain size of about 5 mm, they remain without flowing towards the drainage route, and if left unattended, mold may grow. Therefore, there were limitations to reducing the frequency of maintenance.

[0007] The object of the present invention is to provide a refrigerator that suppresses mold growth by discharging or volatilizing condensation water generated on the inner surface of the refrigerator, and an automatic analyzer equipped with the refrigerator. [Means for solving the problem]

[0008] To solve the aforementioned problems, the present invention provides an automatic analyzer equipped with a refrigerator for keeping a container for reagents or samples cool, wherein a hydrophilic film with 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 with a lower absolute humidity than the air inside the refrigerator into the inner surface of the refrigerator. [Effects of the Invention]

[0009] According to the present invention, since a predetermined hydrophilic film is formed on the inner surface of the refrigerator, the condensed water that is generated does not turn into water droplets and flows easily towards the drainage path. Furthermore, 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 mold growth and an automatic analyzer equipped with said refrigerator can be provided. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows the overall configuration of the automated analyzer according to this embodiment. [Figure 2]A top view of the reagent cooler (lid omitted). [Figure 3] A cross-sectional view of a reagent refrigerator, seen from the side. [Figure 4] A cross-sectional view of the chamber from the side. [Figure 5] A cross-sectional view of the dry air introduction mechanism, seen from the side. [Figure 6] Cross-sectional view of a hydrophilic film observed with a scanning electron microscope. [Figure 7] A graph showing the relationship between the proportion of silicon dioxide particles in the hydrophilic film (solid content of the coating solution) and the contact angle with water. [Figure 8] A graph showing the relationship between the proportion of silicon dioxide in the hydrophilic film (solid content of the coating solution) and pencil hardness. [Figure 9A] A diagram showing the direction of spraying when applying coating liquid to the bottom surface of a chamber. [Figure 9B] A diagram showing the direction of spraying when applying coating liquid to the outer surface of a chamber. [Figure 9C] A diagram showing the direction of spraying when applying coating liquid to the inner surface of a chamber. [Figure 10] A graph showing the relationship between the thickness of the hydrophilic film and the contact angle with water. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments 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 automated analyzer) Figure 1 is an overall configuration diagram of the automated analyzer according to this embodiment. The automated analyzer 1 reacts a sample with a reagent to analyze specific components in the sample, and mainly comprises a rack transport line 7, an incubator disk 9, a sample dispensing tip / reaction vessel transport mechanism 14, a sample dispensing nozzle 10 (sample 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 the rack 6 on which the sample container 5 for accommodating the sample is installed, and can move the sample container 5 to the sample dispensing position 13 near the sample dispensing nozzle 10.

[0014] The incubator disk 9 is formed in a disk shape and a plurality of reaction vessels 8 can be installed in the circumferential direction. By rotation, a predetermined reaction vessel 8 can be moved to a predetermined position. Near the incubator disk 9, a sample dispensing chip / reaction vessel transport mechanism 14 for transporting the sample dispensing chip and the reaction vessel 8 is installed.

[0015] The sample dispensing chip / reaction vessel transport mechanism 14 can move in three directions of the X-axis, Y-axis, and Z-axis, and can transport the sample dispensing chip and the reaction vessel 8 to each position of the sample dispensing chip / reaction vessel holding part 15, the reaction vessel stirring mechanism 16, the sample dispensing chip / reaction vessel waste port 17, the sample dispensing chip mounting position 18, and a predetermined position of the incubator disk 9. Here, a plurality of unused reaction vessels 8 and a plurality of sample dispensing chips are respectively installed in the sample dispensing chip / reaction vessel holding part 15. After the sample dispensing chip / reaction vessel transport mechanism 14 moves above the sample dispensing chip / reaction vessel holding part 15 and then descends to grasp an unused reaction vessel 8, it ascends. Thereafter, the sample dispensing chip / reaction vessel transport mechanism 14 moves above a predetermined position of the incubator disk 9 and then descends to mount the unused reaction vessel 8 on the incubator disk 9. Also, after the sample dispensing chip / reaction vessel transport mechanism 14 moves above the sample dispensing chip / reaction vessel holding part 15 and then descends to grasp an unused sample dispensing chip, it ascends. Thereafter, the sample dispensing chip / reaction vessel transport mechanism 14 moves above the sample dispensing chip mounting position 18 and then descends to install the sample dispensing chip at the sample dispensing chip mounting position 18.

[0016] The sample dispensing nozzle 10 is capable of rotation and vertical movement. After rotating to above the sample dispensing tip mounting position 18, it descends to attach the sample dispensing tip to its tip. Then, the sample dispensing nozzle 10 with the attached sample dispensing tip moves above the sample container 5 held in the rack 6, descends, and aspirates a predetermined amount of sample from the sample container 5. Next, the sample dispensing nozzle 10, having aspirated the sample, moves above the incubator disc 9, descends, and dispenses the sample into an unused reaction vessel 8 held in the incubator disc 9. Once the sample dispensing is complete, the sample dispensing nozzle 10 discards the used sample dispensing tip through the sample dispensing tip / reaction vessel waste port 17.

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

[0018] The reagent dispensing nozzle 11 is capable of rotation and vertical movement. After rotating and moving above the reagent suction hole 20 provided in the lid 19 of the reagent cooler 4, it descends and passes through the reagent suction hole 20. Furthermore, the reagent dispensing nozzle 11 inserts 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, and then dispenses the reagent into the reaction vessel 8 installed on the incubator disk 9. The reaction vessel 8, from which the sample and reagent have been dispensed, moves to a predetermined position by the rotation of the incubator disk 9 and is then transported to the reaction vessel stirring mechanism 16 by the sample dispensing tip / reaction vessel transport mechanism 14.

[0019] The reaction vessel stirring mechanism 16 applies rotational motion to the reaction vessel 8, thereby stirring and mixing the sample and reagents inside the reaction vessel 8. After stirring is complete, the reaction vessel 8 is returned to its designated 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 rotation and vertical movement. After the mixing of the sample and reagents is complete and a predetermined reaction time has elapsed on the incubator disc 9, it moves above the reaction vessel 8, then descends to hold the reaction vessel 8. Subsequently, the reaction vessel transport mechanism 12 rotates to transport the reaction vessel 8 to the detection unit 21.

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

[0022] (Configuration of the reagent refrigerator) Next, the details of the configuration of the reagent refrigerator 4 will be explained using Figures 2 and 3. The following explanation will use a reagent refrigerator for storing reagents as an example, but the same can be applied to a specimen refrigerator for storing specimens. 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. In addition to the reagent container loading section 3, lid 19, and chamber 22 mentioned above, the reagent refrigerator 4 also has 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 automated analyzer is in operation, and can be rotated together with the chamber 22 via the central adapter 24 and the operating shaft 25 as needed. When a predetermined reagent is dispensed, the rotation of the reagent container loading unit 3 positions the reagent container 2 containing the predetermined reagent below the vertical projection of the reagent aspiration port 20. Although not shown in the diagram, a motor for rotating the operating shaft 25 is provided at the lower end of the operating shaft 25.

[0024] In addition to the aforementioned reagent suction hole 20, the lid 19 has an opening for allowing the reagent container 2 to pass through the reagent container loading section 3 when being loaded or unloaded, and an opening / closing lid 23 is also provided for opening and closing this opening. When the amount of reagent in the reagent container 2 loaded in the reagent container loading section 3 decreases or the container becomes empty, the reagent container loading section 3 is lifted by a loader mechanism (not shown) and transported out of the reagent refrigerator 4. After that, the used reagent container 2 is removed from the reagent container loading section 3, and an unused reagent container 2 is loaded into the reagent container loading section 3.

[0025] The chamber 22 is positioned to surround the reagent container loading section 3 and below it, and together with the lid 19 and the opening / closing lid 23, it defines a cooling space for cooling and storing the reagent container 2. The cooling space is cooled by the cooling mechanism 26. A housing 27 is provided on the outside of the chamber 22, via an insulating material 28 to enhance cooling efficiency.

[0026] The cooling mechanism 26 is located below the chamber 22 and is intended to cool the chamber 22. It is preferable that it be composed of 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 cooling mechanism 26 can efficiently cool the chamber 22.

[0027] Here, since the lid 19 is provided with a reagent suction hole 20 through which the reagent dispensing nozzle 11 passes and an opening through which the reagent container loading section 3 passes, it is unavoidable that outside air enters the refrigerated space, and moisture contained in the outside air condenses on the inner surface of the chamber 22. Therefore, a drainage channel 31 for draining the condensed water and, if necessary, an inclined surface that slopes downward toward the drainage channel 31 are formed on the bottom surface of the chamber 22.

[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 towards the drain 31. Figure 4 is a cross-sectional view of the chamber from the side. If the inner surface of the chamber 22 were not formed with a hydrophilic film, the condensed water would adhere to the inner surface of the chamber 22 as water droplets and would not flow towards the drain 31 until they reached a certain size (approximately 5 mm in diameter or more). In contrast, in this embodiment, by forming a hydrophilic film 32 on the inner surface of the chamber 22 with a contact angle with water of 15° or less, 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, more than 90% of the condensed water is discharged from the drain 31.

[0029] However, some of the condensed water is not discharged through the drain 31 and remains as a water film on the inner surface of the chamber 22. Therefore, the reagent refrigerator 4 of this embodiment not only forms a hydrophilic film on the inner surface of the chamber 22, but is also equipped with a dry air introduction mechanism 33 that introduces dry air into the chamber 22, thereby quickly volatilizing the water film remaining on the inner surface. This suppresses the growth of mold on the inner surface of the chamber 22.

[0030] Figure 5 is a cross-sectional view of the dry air introduction mechanism from the side. The purpose of the dry air introduced by the dry air introduction mechanism 33 into the reagent refrigerator 4 (specifically the chamber 22) is to dry the condensation inside the reagent refrigerator 4, so it is necessary that the absolute humidity of the dry air be lower than the absolute humidity of the air inside the reagent refrigerator 4. As shown in Figure 5, the dry air introduction mechanism 33 mainly comprises a fan 35, a filter 36, aluminum fins 40, an aluminum fin holder 38, a heat exchanger 37, piping 39, and a trough 41.

[0031] Fan 35 is driven (rotates) when outside air 34 is taken into the reagent cooler 4 (dry air introduction mechanism 33), and filter 36 removes dust and other particles from the outside air. Aluminum fins 40 cool the outside air 34 by coming into contact with the outside air 34 that has passed through filter 36, and aluminum fin holder 38 holds the aluminum fins 40. Heat exchanger 37 supplies cooled refrigerant into piping 39. Piping 39 is made of aluminum and is provided to penetrate the aluminum fin holder 38 at multiple points, so that the aluminum fin holder 38 and aluminum fins 40 are cooled by the refrigerant supplied from heat exchanger 37. Gutter 41 is formed to slope downward toward the drain ditch 31, and plays the role of receiving condensation water that flows down from the aluminum fins 40 due to contact with the outside air 34 and guiding it to the drain ditch 31.

[0032] Of the dry air that passes through the dry air introduction mechanism 33 (aluminum fins 40), some is discharged outside the refrigerator through the drain channel 31, but the remainder is supplied back up the drain channel 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, drying the inner surface of the chamber 22 and suppressing mold growth. In addition, the introduction of dry air creates positive pressure inside the chamber 22, reducing the amount of outside air entering through the reagent suction hole 20 and the opening (opening / closing lid 23), thus suppressing condensation itself. Note that the configuration of the dry air introduction mechanism 33 shown in Figure 5 is merely an example, and other configurations are also acceptable.

[0033] (hydrophilic film) <Overview> As described above, in the reagent cooler 4 of the automatic analyzer of this embodiment, a hydrophilic film 32 is formed on the inner surface of the chamber 22, and the contact angle of the hydrophilic film 32 with water is 15° or less. If the contact angle with water is higher than 15°, condensation water is less likely to form a water film, making it difficult to discharge from the drain channel 31, and it is more likely to remain without volatilizing even when dry air is introduced. Furthermore, it is desirable that the hydrophilic film 32 formed on the inner surface of the chamber 22 not only has high water resistance but also high hardness so that it is less likely to be scratched even when it comes into contact with the reagent container loading section 3 and reagent containers 2. Therefore, in this embodiment, the hydrophilic film 32 is formed using silicon dioxide particles and a binder.

[0034] Figure 6 is a cross-sectional view of a hydrophilic film observed with a scanning electron microscope. According to Figure 6, silicon dioxide particles 43 and voids 44, which constitute the hydrophilic film, can be seen on the substrate 42. Although not visible in Figure 6, silicon dioxide binder is also present between multiple silicon dioxide particles 43 and on the surface of the substrate 42, maintaining the film structure. The contact angle of silicon dioxide itself with water is about 30°, but the fine irregularities caused by the silicon dioxide particles 43 on the surface of the hydrophilic film reduce the contact angle with water. Furthermore, due to capillary action, condensed water seeps into the voids 44 inside the hydrophilic film, further reducing the contact angle with water. 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 complex as shown in Figure 4, it is preferable to apply the coating solution for forming the hydrophilic film by spray coating rather than by methods such as dip coating or spin coating. Furthermore, after the coating solution is applied, the binder precursor contained in the coating solution hardens through heat curing, forming a binder and creating a hydrophilic film.

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

[0037] ≪Silicon dioxide particles≫ The average particle size of silicon dioxide particles used is approximately 5 to 50 nm. If the particle size is too small, it becomes more likely to float in the air as dust during the preparation of the coating solution. Also, as the particle size decreases, the surface area per unit weight increases, making it more prone to static electricity. In particular, during winter, it tends to adhere to walls and other surfaces in the manufacturing area. Therefore, from the standpoint of ease of handling, the lower limit of the particle size is 5 nm. Considering the distribution of particle sizes, a lower limit of 10 nm for the average particle size is desirable.

[0038] On the other hand, while larger particle sizes are easier to handle during the preparation of the coating solution, the number of voids between particles after film formation decreases, which tends to reduce hydrophilicity. Also, coating solutions prepared using silicon dioxide particles with a particle size of 5-50 nm show almost no precipitation of silicon dioxide particles even after long-term storage. However, when larger silicon dioxide particles are used, silicon dioxide particles will precipitate at the bottom of the coating solution after long-term storage. The density of silicon dioxide is originally around 2.5, which is higher than that of general-purpose organic solvents with a density of about 0.7-1.1. Therefore, silicon dioxide with a large particle size will sink, but silicon dioxide with a small particle size will have its precipitation suppressed by interactions such as collisions with solvent molecules. Due to this effect, precipitation is suppressed up to a particle size of about 50 nm, but precipitation occurs at larger sizes. Considering the particle size distribution, an upper limit of 30 nm for the average particle size is desirable.

[0039] In summary, the average particle size of silicon dioxide particles used in the coating solution should be between 5 nm and 50 nm, and more preferably between 10 nm and 30 nm. Some particles may consist of several to a dozen or so particles of 10 nm or more and 30 nm or less linked together; however, these are also preferable because they do not easily settle in the solvent.

[0040] <Precursor of silicon dioxide binder> Although silicon dioxide is insoluble in organic solvents, some of its precursors are soluble in them. In this embodiment, a silicon dioxide precursor soluble 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 multiple tetraalkoxysilanes undergo partial hydrolysis, the alkoxy groups are removed, and multiple molecules form silicon-oxygen-silicon bonds, resulting in an average molecular weight of several thousand to tens of thousands. Silica sol is soluble in alcohol-based solvents such as methanol and ethanol. Among tetraalkoxysilanes, tetraethoxysilane is the easiest to use. Tetramethoxysilane, which has a shorter alkyl chain, is highly reactive with water, so if stored for a long period in a high-humidity environment, the coating liquid that forms the hydrophilic film may solidify. Furthermore, tetrapropoxysilane and tetrabutoxysilane, which have longer alkyl chains than tetraethoxysilane, are less susceptible to hydrolysis, which tends to result in longer heat curing times after application or slower thermal curing reactions unless the heating temperature is increased. Therefore, tetraethoxysilane is preferred as the tetraalkoxysilane used to form the silica sol.

[0041] Besides silica sols, compounds containing silicon atoms with four bonding groups in the molecule, three alkoxy groups, and other non-alkoxy bonding groups such as benzene rings or alkyl chains can also be used as precursors for silicon dioxide binders. However, when using these materials, the hydrophilic film will contain not only silicon dioxide but also atoms such as carbon, nitrogen, and sulfur.

[0042] Specific examples of compounds 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-isocyanatetopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

[0043] Organic solvents As the solvent for the coating solution, it is preferable to use one that can dissolve the silicon dioxide binder precursor. In this respect, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol are preferred. Pentanol, hexanol, octanol, and others with longer hydrocarbon chains make it difficult to dissolve the silicon dioxide binder precursor, and in some cases, it may even separate. Also, since longer hydrocarbon chains result in higher boiling points, there is a possibility of dripping after application, so it is desirable that the carbon number of the alcohol be 4 or less, i.e., the upper limit is butanol. Furthermore, the silicon dioxide binder precursor is also easily soluble in diols such as ethylene glycol and diethylene glycol. However, diols have higher boiling points than alcohols such as ethanol and butanol, and drying takes a long time after application, so they are not practical solvents.

[0044] ≪Mixing ratio≫ The hydrophilic film is formed by the solid components in the coating solution, namely silicon dioxide particles and precursors of the silicon dioxide binder. When applying the coating to the inner surface of the chamber 22 by spray coating, if the solid component ratio in the coating solution is high, the nozzle is likely to clog, and even if it does not clog, the solid components may accumulate near the nozzle and change the direction of the spray. For this reason, it is desirable to keep the concentration of solid components in the coating solution to a maximum of 1% by weight, and not to use coating solutions with a higher concentration. In other words, it is preferable that the proportion of organic solvent in the coating solution that forms the hydrophilic film be 99% by weight or more.

[0045] The contact angle between a hydrophilic film and water can vary depending on the mixing ratio of two materials: silicon dioxide particles and the silicon dioxide binder precursor. This is because silicon dioxide particles are the source of hydrophilicity, and the higher the proportion of silicon dioxide particles, the lower the contact angle with water tends to be.

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

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

[0048] Figure 8 is a graph showing the relationship between the proportion of silicon dioxide in the hydrophilic film (solid content of the coating solution) and pencil hardness. Similar to Figure 7, Figure 8 shows an example where the silicon dioxide particle size is 10 nm, the heat curing time after spray coating is 1 hour, the heat curing temperature is 180°C, and the hydrophilic film thickness is 100 nm.

[0049] As shown in Figure 8, the physical strength of the hydrophilic film decreased as the proportion of silicon dioxide particles increased, that is, as the proportion of silicon dioxide binder precursors decreased. When the proportion 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 acceptable for practical purposes. However, when the proportion of silicon dioxide particles was 85% by weight, the pencil hardness of the hydrophilic film decreased to about 2B. Assuming that the material of reagent container 2, etc., is an acrylic or polyethylene terephthalate resin, the pencil hardness of these resins is about 2B to H, so if reagent container 2, etc., is accidentally dropped onto the hydrophilic film, the hydrophilic film may be damaged. Therefore, it is preferable that the proportion of silicon dioxide particles in the solid content of the coating liquid forming the hydrophilic film be 80% by weight or less, in other words, that the proportion of silicon dioxide binder precursors be 20% by weight or more.

[0050] Considering both the contact angle with water and the pencil hardness as 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 mentioned above, when applying a coating solution to the inner surface of a chamber 22 with a complex shape, spray coating is preferable. Here, a method for applying a coating solution to the inner surface of the chamber 22 by spray coating will be specifically explained with reference to Figures 9A to 9C.

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

[0053] In all cases shown in Figures 9A to 9C, the spray gun 45 applies droplets 47 of the coating liquid to one side of the chamber 22's axis while the chamber 22 is rotated on a table (not shown), thereby allowing the coating liquid to be applied to the entire inner surface of the chamber 22 with a uniform thickness. While smaller droplet sizes make it easier to control the film thickness uniformly, the application time increases, so if the droplets are too small, the throughput during mass production tends to decrease. Also, reducing the size of the droplets 47 requires reducing the nozzle diameter of the spray gun 45, in which case solid particles in the coating liquid are more likely to clog the nozzle tip or its vicinity. Therefore, the size of the droplets 47 is preferably about 10 to 100 μm, and more preferably 10 to 50 nm.

[0054] Next, we will explain the results of our investigation into the optimal hydrophilic film thickness for achieving sufficient hydrophilicity. Figure 10 is a graph showing the relationship between the hydrophilic film thickness and the contact angle with water. Figure 10 shows an example where the silicon dioxide particle diameter is 10 nm, the proportion of silicon dioxide particles in the solid content of the coating solution forming the hydrophilic film is 50% by weight, the heat curing time after spray coating with the coating solution is 1 hour, and the heat curing temperature is 180°C.

[0055] As shown in Figure 10, when the hydrophilic film thickness was 50 nm or more, the contact angle with water was approximately 5°. Furthermore, it was found that a film thickness of 40 nm or more is necessary to obtain a hydrophilic film with a contact angle of 15° or less. A lower contact angle results in a thinner water film when condensation occurs, so 5° is preferable to 15°. Therefore, a hydrophilic film thickness of 50 nm or more is preferable. The reason why a thinner hydrophilic film results in a higher contact angle is presumed to be because the gaps between particles become shallower, weakening the capillary action.

[0056] In practice, when the coating solution was applied to the chamber 22 with a spray gun to form a hydrophilic film, a film thickness variation of approximately ±30-50% occurred. This is thought to be due to the complex shape of the chamber 22. In other words, even if an average film thickness of 50 nm is targeted, it may be as thin as 25 nm in some areas. Therefore, considering the film thickness variation, it is preferable to target an average film thickness of 100 nm or more for the hydrophilic film.

[0057] The following will explain the examples and comparative examples. [Examples]

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

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

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

[0061] (Verification using a refrigerator (automatic analyzer) with a built-in chamber) As described above, the chamber with the hydrophilic membrane formed was installed in the reagent cooler of a Hitachi High-Tech e-801 automated immunoassay analyzer. Next, the inside of the reagent cooler was cooled until the temperature inside the reagent containers reached 5°C, and then the reagent container loading section was installed inside the chamber, into which the reagent containers were inserted. Subsequently, the automated analyzer was operated, and reagents aspirated from each reagent container were discharged into the reaction vessel containing the sample, and specific components contained in the sample were qualitatively / quantitatively analyzed by color reaction or luminescence reaction, etc. During the operation of the automated analyzer, dry air was constantly introduced into the reagent cooler using the dry air introduction mechanism shown in Figure 5, creating a positive pressure of approximately 0.001 atmospheres inside the reagent cooler compared to the outside. After operating the automated analyzer for two weeks while maintaining the temperature inside the reagent cooler at 5°C, the inner surface of the chamber was observed. The inner surface of the chamber was found to be almost dry, and no mold growth was observed.

[0062] On the other hand, a chamber that did not form a hydrophilic membrane was also placed in the reagent refrigerator of a Hitachi High-Tech e-801 automated immunoassay analyzer and operated for two weeks under the same conditions as described above. After that, the inner surface of the chamber was observed. The inner surface of the chamber was found to be wet with water droplets due to condensation, and mold growth was confirmed in some areas.

[0063] Based on the above, it has become clear that by forming a hydrophilic film with a contact angle of 5° with water on the inner surface of the chamber, mold growth can be suppressed even when the automated 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 (0.4g), silica sol solution B (7.5g), and Solmix AP-7 (287.6g), an industrial ethanol manufactured by Nippon Alcohol Sales Co., Ltd., were added to a 1000ml polypropylene bottle. After sealing the bottle, the mixture was stirred several times to prepare a coating solution (hydrophilic coating solution D) (300g) that forms a hydrophilic film with a solid content of 0.1% by weight and silicon dioxide particles accounting for 20% by weight of the solid content. The contact angle with water of the hydrophilic film formed using the hydrophilic coating solution D prepared in Example 2 was 8°. All other conditions were the same as in Example 1.

[0065] After installing a chamber with a hydrophilic film in it into a reagent refrigerator and running an automated analyzer for two weeks, observation of the inside of the reagent refrigerator revealed that the inner surface of the chamber was almost completely dry, and no mold growth was observed.

[0066] From the above, it has become clear that by forming a hydrophilic film with a contact angle of 8° with water on the inner surface of the chamber, mold growth can be suppressed even when the automated analyzer is operated for a relatively long period of time. [Examples]

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

[0068] After installing a chamber with a hydrophilic film in it into a reagent refrigerator and running an automated analyzer for two weeks, observation of the inside of the reagent refrigerator revealed that the inner surface of the chamber was almost completely dry, and no mold growth was observed.

[0069] From the above, it has become clear that by forming a hydrophilic film with a contact angle of 15° with water on the inner surface of the chamber, mold growth can be suppressed even when the automated 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 (0.2g), silica sol solution B (11g), and Solmix AP-7 (238.8g), an industrial ethanol manufactured by Nippon Alcohol Sales Co., Ltd., were added to a 1000ml polypropylene bottle. After sealing the bottle, the mixture was stirred several times to prepare a coating solution (hydrophilic coating solution F) (250g) that forms a hydrophilic film with a solid content of 0.1% by weight and silicon dioxide particles accounting for 12% by weight 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°. All other conditions were the same as in the Examples.

[0071] After installing a chamber with a hydrophilic film formed on it into a reagent refrigerator and running an automated analyzer for two weeks, observation of the inside of the reagent refrigerator revealed that no mold growth was observed on the inner surface of the chamber, but a water film was found in several places.

[0072] From the above, it was found that when the contact angle between the hydrophilic film formed on the inner surface of the chamber and water is 20°, condensation water cannot be completely removed. Furthermore, when the automated analyzer was operated for another four weeks, black mold began to grow on some of the water film that had adhered in places.

[0073] Considering the examples and Comparative Example 1, it can be concluded that if the contact angle between the hydrophilic film formed on the inner surface of the chamber and water exceeds 15°, the growth of mold caused by condensation may not be suppressed. This is thought to be because a larger contact angle with water results in a thicker water film, increasing the amount of condensation that adheres to the inner surface of the chamber. Therefore, in order to reliably drain the condensation that occurs on the inner surface of the refrigerator, it is important to form a hydrophilic film with a contact angle with water of 15° or less on the inner surface of the refrigerator's chamber.

[0074] (Comparative Example 2) In Comparative Example 2, unlike in Example 1, the dry air introduction mechanism was stopped, and dry air was not introduced into the reagent refrigerator. All other conditions were the same as in Example 1.

[0075] After running the automated analyzer for two weeks, an inspection of the inside of the reagent refrigerator revealed no mold growth on the inner surface of the chamber. The areas far from the drain were dry, but the areas near the drain were covered with a water film. Furthermore, an examination of the amount of water flowing out of the drain revealed that most of the condensation was being discharged through the drain.

[0076] From the above, it was found that if dry air is not introduced into the refrigerator, condensation water remains on the inside of the refrigerator as a small film of water, and it is not possible to completely remove the condensation water. Furthermore, when the automated analyzer was operated for another four weeks, black mold began to grow on some of the water film that had adhered to the area near the drain.

[0077] Considering the examples and comparative example 2, it can be said that introducing dry air into the interior of the refrigerator is important in order to ensure that the condensation water generated on the interior of the refrigerator evaporates completely.

[0078] (Comparative Example 3) In Comparative Example 3, unlike in the Example, only the function of the dry air introduction mechanism that dries the outside air was stopped, and normal outside air was introduced into the reagent refrigerator instead of dry air. All other conditions were the same as in Example 1.

[0079] After running the automated analyzer for two weeks, an inspection of the inside of the reagent refrigerator revealed no mold growth on the inner surface 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 Comparative Example 2. Hiro Furthermore, upon examining the amount of water flowing out of the drain, it was found that most of the condensation water was being discharged through the drain.

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

[0081] Considering the examples and comparative example 3, it can be said that in order to ensure that the condensation water generated on the inside of the refrigerator evaporates, it is important to introduce dry air, rather than outside air, into the interior of the refrigerator. [Explanation of symbols]

[0082] 1...Automatic analyzer, 2...Reagent container, 3...Reagent container loading unit, 4...Reagent refrigerator, 5...Sample container, 6...Rack, 7...Rack transport line, 8...Reaction vessel, 9...Incubator disc, 10...Sample dispensing nozzle, 11...Reagent dispensing nozzle, 12...Reaction vessel transport mechanism, 13...Sample dispensing position, 14...Sample dispensing tip / reaction vessel transport mechanism, 15...Sample dispensing tip / reaction vessel holding unit, 16...Reaction vessel stirring mechanism, 17...Sample dispensing tip / reaction vessel waste port, 18...Sample dispensing tip mounting position, 19...Lid 20…Reagent suction port, 21…Detection unit, 22…Chamber, 23…Opening / closing lid, 24…Adapter, 25…Moving shaft, 26…Cooling mechanism, 27…Housing, 28…Insulation material, 30…Condensation water, 31…Drainage channel, 32…Hydrophilic membrane, 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…Substrate, 43…Silicon dioxide particles, 44…Void, 45…Spray gun, 46…Bottom surface, 47…Droplet, 48…Outer circumference side surface, 49…Inner circumference side surface

Claims

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

2. In claim 1, The hydrophilic film contains silicon dioxide, and the automated analyzer.

3. In claim 2, An automated analyzer in which 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, An automatic liquid separator having voids between silicon dioxide particles in the hydrophilic film.

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

6. In claim 1, An automated analyzer in which the average thickness of the hydrophilic film is 100 nm or more.

7. In a refrigerator used to keep stored items cold, A hydrophilic film with a contact angle of 15° or less with water is formed on the inner surface of the aforementioned refrigerator. A refrigerator having a dry air introduction mechanism that introduces air with a lower absolute humidity than the air inside the refrigerator into the inner surface of the refrigerator.

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