Ultrasonic cleaning machine and automated analyzer using the same

Abstract

To provide an ultrasonic cleaner which has a constitution suitable for mounting in a narrow space such as a carrying rack and is reduced in liquid surface fluctuation, liquid level variation, and mist generation and can irradiate an outer peripheral part of a nozzle with a powerful ultrasonic wave.SOLUTION: The ultrasonic cleaner includes: a cleaning tank having a liquid storage part for storing therein a liquid; and an ultrasonic vibrator having a piezoelectric element and a front mass. A through hole having openings on an outer wall surface of the cleaning tank and an inner wall surface of the liquid storage part is provided in a side surface part of the cleaning tank, and the front mass is inserted to the through hole, and a cover is installed so as to cover a space above a front end surfaces of the front mass, and the cover is movable at least upward.SELECTED DRAWING: Figure 2B

Description

Technical Field

[0005]

[0001] The present disclosure relates to an ultrasonic cleaner and an automatic analyzer using the same.

Background Art

[0002] An automatic analyzer mixes a sample such as serum or urine with a reagent and performs component analysis by measuring the transmittance of light irradiated on the mixed solution. In an automatic analyzer, since the same nozzle is repeatedly used to dispense samples, a nozzle cleaning process is performed to wash the tip of the nozzle with a water stream before sucking another sample. However, in an automatic analyzer with high throughput performance, since the dispensing process is performed at high speed, sufficient time cannot be used for nozzle cleaning. Therefore, dirt derived from sample components may accumulate at the tip of the nozzle, and it is dealt with by removing it during daily cleaning and maintenance.

[0003] When dirt accumulates at the tip of the nozzle, variations in the dispensing volume and carry-over of the previous sample component into the next sample are likely to occur, and the measurement accuracy decreases.

[0004] Patent Document 1 discloses an ultrasonic cleaner having a diaphragm to which a bolt-tightened Langevin oscillator (BLT) is attached, which has a configuration in which an opening is provided on the side surface of a cleaning tank for storing a cleaning liquid, and this opening is closed with a diaphragm, and generates cavitation by ultrasonic waves (a phenomenon in which bubbles are generated and disappear due to a pressure difference generated in a liquid), and cleans a dispensing nozzle.

[0005] Further, Patent Document 2 discloses a cleaning rack that includes a cleaning tank, an ultrasonic generating element, and an electronic circuit that controls the ultrasonic generating element in order to automate maintenance work, and cleans a nozzle used for sucking and discharging a sample or a reagent in the cleaning tank, and is movable along a transport line.

[0006] Patent Document 3 discloses an ultrasonic cleaner having a vibrating head having a neck extending from an ultrasonic transducer toward a cleaning tank and a tip having a cylindrical hole whose longitudinal direction is in the vertical direction, and a cover having an opening corresponding to the neck and the cylindrical hole, the cover being installed at a height that is in contact with the surface of the cleaning fluid so as to cover the cleaning tank. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2017 / 002740 [Patent Document 2] Japanese Patent Publication No. 2014-89200 [Patent Document 3] International Publication No. 2020 / 044998 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] When adding a unit capable of cleaning and maintaining the nozzles to an automated analyzer that has already been delivered and is in actual use, it is desirable to add a small cleaning unit to the narrow space remaining between the existing components, or to add it temporarily during maintenance. This is because major hardware changes have problems such as high modification costs and periods during which analysis cannot be performed.

[0009] The cleaning rack described in Patent Document 2 has a configuration in which an ultrasonic generating element (piezoelectric element) is directly installed on the bottom or side surface of the cleaning tank.

[0010] In conventional ultrasonic cleaners, when a piezoelectric element is installed, a large area such as the bottom of the cleaning tank is used as a diaphragm to amplify the amplitude of the ultrasonic irradiation surface, and this vibration further generates standing waves in the liquid. Standing waves have regions where the sound pressure is high (antinodes of the standing waves), and cavitation occurs in these regions. Because cleaning is done on this principle, racks that require a smaller bottom (or side) area compared to commercially available ultrasonic cleaners do not generate sufficient amplitude, making it difficult to obtain the cleaning effect due to cavitation generation. In particular, the cleaning efficiency is low when cleaning the tips of small diameter nozzles of 1 mm or less.

[0011] To replace manual cleaning and maintenance with ultrasonic cleaning of the nozzle's outer circumference, it is necessary to create a high-sound-pressure region around the nozzle tip where ultrasonic cavitation can stably occur.

[0012] Patent Document 1 describes an ultrasonic cleaner in which a cleaning head attached to the tip of an ultrasonic transducer is vibrated to concentrate cleaning on the nozzle tip, generating ultrasonic cavitation within the hollow section into which the nozzle is inserted. In this configuration, the vibration amplified by the cleaning head is used to generate strong cavitation on the outer circumference of the nozzle tip. However, since the cleaning head is inserted from above the liquid surface in the cleaning tank, and the cleaning head vibrates in both the liquid and the air with the liquid surface in between, there is a risk of large fluctuations in the liquid level and splashing of liquid, making it unsuitable for transport-type cleaning methods. Cleaners with large liquid fluctuations, such as this one, use a cleaning tank that can overflow to maintain a constant liquid level, but this is difficult to use in transport-type cleaning where the size is limited.

[0013] The ultrasonic cleaner described in Patent Document 3 has a cover that surrounds the cleaning tank, but the tip of the vibrating head has a special shape, making it difficult to make the dimensions (height) compact. Furthermore, there is room for improvement in terms of the time and effort required to attach and detach the cover.

[0014] The present disclosure aims to provide an ultrasonic cleaning machine that has a configuration suitable for mounting in a narrow space such as a transport rack, has little shaking of the liquid surface, fluctuation of the liquid level, and generation of fog, and can irradiate strong ultrasonic waves to the outer peripheral portion of the nozzle.

Means for Solving the Problems

[0015] The ultrasonic cleaning machine of the present disclosure includes a cleaning tank having a liquid storage portion for storing liquid, and an ultrasonic vibrator having a piezoelectric element and a front mass. A through hole having openings in the outer wall surface of the cleaning tank and the inner wall surface of the liquid storage portion is provided on the side surface portion of the cleaning tank. The front mass is inserted into the through hole, and a cover is installed so as to cover the upper side of the front end surface of the front mass. The cover is movable at least upward.

Effects of the Invention

[0016] According to the present disclosure, it is possible to provide an ultrasonic cleaning machine that has a configuration suitable for mounting in a narrow space such as a transport rack, has little shaking of the liquid surface, fluctuation of the liquid level, and generation of fog, and can irradiate strong ultrasonic waves to the outer peripheral portion of the nozzle.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view showing an automatic analyzer of an embodiment. [Figure 2A] It is a top view showing an example of the configuration of a cleaning portion of an ultrasonic cleaning machine of an embodiment. [Figure 2B] It is a cross-sectional view taken along the line A-A of FIG. 2A. [Figure 2C] It is an enlarged view of the inside of the broken-line frame in FIG. 2B. [Figure 2D] It is a front view showing the cleaning portion of FIG. 2A. [Figure 2E] It is a side view showing the cleaning portion of FIG. 2A. [Figure 2F] It is a perspective view showing the cleaning portion of FIG. 2A. [Figure 2G] It is a front view showing a state where the upper block is removed from the cleaning portion of FIG. 2A. [Figure 2H] It is a perspective view showing a state where the upper block is removed from the cleaning portion of FIG. 2A. [Figure 3A] It is a schematic diagram showing the sound pressure distribution and flow velocity generated at the front mass tip of the ultrasonic cleaner when no cover is provided on the cleaning tank. [Figure 3B] It is a schematic diagram showing the sound pressure distribution and flow velocity generated at the front mass tip of the ultrasonic cleaner when a cover is provided on the cleaning tank. [Figure 4] It is a top view showing an example of the arrangement of the cover in the cleaning tank of the embodiment. [Figure 5] It is a configuration diagram showing an example of a cleaning rack having the ultrasonic cleaner of the embodiment. [Figure 6] It is a flowchart showing a method for cleaning a dispensing nozzle by an ultrasonic cleaner. [Figure 7] It is a graph showing an example of a driving pattern of an ultrasonic vibrator. [Figure 8] It is a configuration diagram showing an automatic analyzer corresponding to the case of using the ultrasonic cleaner built in the transport rack of the embodiment.

Embodiments for Carrying Out the Invention

[0018] The ultrasonic cleaner of the present disclosure includes a cleaning tank having a recess (liquid storage part) into which a dispensing nozzle to be cleaned can be inserted, and an ultrasonic vibrator having a piezoelectric element and a front mass. On the side surface of the cleaning tank, a through hole having openings on the outer wall surface of the cleaning tank and the inner wall surface of the recess is provided. The front mass is inserted into the through hole, and the tip of the front mass is arranged to irradiate ultrasonic waves from the side of the dispensing nozzle.

[0019] In addition to the above configuration, a removable upper block is provided on the upper part of the cleaning tank, and a cover that covers the tip of the front mass is arranged between the upper block and the cleaning tank in a state where it is not fixed (a state of floating due to the rise of the liquid level). Further, it is desirable to provide an opening on the base side of the front mass of the upper block.

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

Examples

[0021] Figure 1 is a perspective view showing the automated analyzer of an embodiment.

[0022] As shown in this figure, the automated analyzer 10 consists of a reagent disk 12 on which multiple reagent containers 11 are placed, a reaction disk 13 for mixing reagents and samples and measuring the reaction, a reagent dispensing mechanism 14 for aspirating and dispensing reagents, and a sample dispensing mechanism 15 for aspirating and dispensing samples.

[0023] The reagent dispensing mechanism 14 is equipped with a reagent nozzle 21 for dispensing reagents. The sample dispensing mechanism 15 is equipped with a sample nozzle 22 for dispensing samples. Here, nozzles such as the reagent nozzle 21 and the sample nozzle 22 are collectively referred to as "dispensing nozzles".

[0024] The samples placed in the device are placed in sample containers 23 (test tubes) and then placed on racks 24, which are then transported on a transport line 25. Multiple sample containers 23 are placed on racks 24. The samples are blood-derived samples such as serum or whole blood, or urine, etc.

[0025] The sample dispensing mechanism 15 moves the sample nozzle 22 to a suction position for aspirating a sample from the sample container 23, a discharge position for dispensing into the cell 26 (which, as shown in the enlarged view in the figure, is a container divided into small sections), and a washing position where a washing tank 27 is located for rinsing the tip of the sample nozzle 22 with water. Furthermore, the sample dispensing mechanism 15 lowers the sample nozzle 22 to match the height of the sample container 23 at the suction position, the height of the cell 26 at the discharge position, and the height of the washing tank 27 at the washing position.

[0026] In summary, the sample dispensing mechanism 15 is configured to move the sample nozzle 22 to each stop position by rotational movement and vertical movement.

[0027] The control of the sample dispensing mechanism 15 and other devices such as the transport line 25 is performed by a control unit (not shown). The automatic analyzer 10 also has a measurement unit (not shown) that analyzes the concentration of predetermined components contained in the sample by photometry of the mixture of sample and reagent contained in the cell 26. The measurement unit has, for example, a light source and a photometer. The photometer is, for example, an absorbance photometer or a scatter photometer.

[0028] The cleaning rack 30, equipped with an ultrasonic cleaner, has a cleaning section described later and is used to clean the tip of the sample nozzle 22 that has come into contact with the sample. It is used during the daily maintenance of the automated analyzer 10, usually before or after analysis. If a large number of samples are handled in a day, the cleaning rack 30 may be used by moving it along the transport line 25 between analyses. This helps to maintain the cleanliness of the sample nozzle 22.

[0029] The washing rack 30 can wash any sample nozzle 22 or reagent nozzle 21 that can access the transport line 25, not limited to samples. While it is possible to wash multiple sample nozzles 22 during a single transport cycle, reusing the contaminated washing solution may cause re-adhesion of contaminants. Therefore, it is desirable to replace the washing solution for each nozzle. In this case, methods include sending one washing rack 30 through the transport line 25 multiple times, or sending multiple washing racks 30 through the transport line 25.

[0030] Furthermore, the conveying method for the conveying line 25 can include a belt that moves along the conveying line 25, a push claw, or a method that utilizes electromagnetic force.

[0031] Figure 2A is a top view showing an example of the configuration of the cleaning section of the ultrasonic cleaning machine in this embodiment.

[0032] In this figure, the cleaning unit comprises two ultrasonic transducers 201A and 201B (excitation units), a cleaning tank 202, and an upper block 203 attached to the top of the cleaning tank 202. The upper block 203 is provided with a through hole 211 and an opening 212. The through hole 211 is provided for cleaning the sample nozzle. The through hole 211 is located where a cleaning hole 210 provided in the cover, which will be described later, is exposed. The sample nozzle is inserted into the liquid below through the cleaning hole 210. Therefore, the through hole 211 is also called a "cleaning opening".

[0033] Furthermore, the opening 212 is provided to supply liquid to the liquid storage section within the cleaning tank 202. The opening 212 also serves to mitigate fluctuations in the liquid level, which will be described later. Therefore, the opening 212 is also called the "liquid injection opening."

[0034] Figure 2B is a cross-sectional view of AA in Figure 2A.

[0035] As shown in Figure 2B, the liquid reservoir 213, which is a recess located in the center of the cleaning tank 202, is provided with through holes 214 that penetrate to the liquid reservoir 213 from the left and right sides in the figure. In other words, the through holes 214 have openings on the side surfaces of the cleaning tank 202 and on the inner wall surfaces of the liquid reservoir 213 (recess). Ultrasonic transducers 201A and 201B are inserted into the two through holes 214, respectively. The ultrasonic transducers 201A and 201B are fixed to the side surfaces of the cleaning tank 202 by flanges 204 and seals 205 (O-rings). The flanges 204 may be separate components from the ultrasonic transducers 201A and 202B. In practice, the ultrasonic transducers 201A and 201B are fixed to the cleaning tank 202 by pressing the flange 204 (or another fixing part for holding the ultrasonic transducers 201A and 201B) against it using screws, including fastening bolts 209. This configuration prevents liquid leakage from the through-hole 211.

[0036] The ultrasonic transducers 201A and 201B have a similar configuration.

[0037] The ultrasonic transducers 201A and 201B consist of a front mass 225 (front metal block), a back mass 226 (rear metal block), multiple piezoelectric elements 207, multiple electrodes 208 (copper plates), and fastening bolts 209. The piezoelectric elements 207 and electrodes 208 each have a configuration in which two are alternately stacked. The stacked piezoelectric elements 207 and electrodes 208 are sandwiched between the front mass 225 and the back mass 226 and fixed by fastening bolts 209.

[0038] In this figure, the piezoelectric elements 207 and electrodes 208 are shown stacked in alternating configurations of two each. However, the ultrasonic transducer according to this disclosure is not limited to this configuration, and may also have a configuration of four alternating stacked elements or any other number of elements.

[0039] The ultrasonic transducers 201A and 201B are characterized by having an elongated cylindrical metal part at their tip. In other words, the tip of the front mass 225 is made of an elongated cylindrical metal.

[0040] In summary, the ultrasonic transducers 201A and 201B have a bolt-clamped configuration, similar to typical bolt-clamped Langevin type transducers (BLTs). The BLT configuration is advantageous for amplitude amplification and is therefore used when utilizing high-power ultrasound, including in industrial ultrasonic cleaning machines where powerful cleaning performance is required.

[0041] Figure 2C is an enlarged view of the area within the dashed frame in Figure 2B, showing details of the main parts of the cleaning section.

[0042] As shown in Figure 2C, a recess 235 is provided on the lower surface of the upper block 203. The recess 235 is located above the liquid reservoir 213 and the front end surface 215 of the front mass 225. A cover 216 is installed between the cleaning tank 202 and the upper block 203. The width of the cover 216 is smaller than that of the recess 235. A cleaning hole 210 is provided in the center of the cover 216. Because the recess 235 is wider than that of the cover 216, it provides space for the cover 216 to move when the cover 216 floats on the liquid surface below.

[0043] To prevent the liquid from overflowing above the top surface of the cover 216, it is desirable to use a material for the cover 216 that floats on liquid, such as a resin. Conversely, if there is liquid above the cover 216, it is desirable to use a metal that does not float on the liquid and can block ultrasonic waves. Note that even if the cover 216 is made of metal, if it is an aluminum alloy foil, it will float on the liquid surface.

[0044] By driving the ultrasonic transducers 201A and 201B at their resonant frequencies, the amplitude of the tip surface 215 of the front mass 225 can be maximized.

[0045] It is desirable that the ultrasonic transducers 201A and 201B are configured such that vibration nodes (regions with consistently small amplitude) are generated in the range from the flange 204 to the stepped portion of the front mass 225 (the connection point between the small-diameter and large-diameter sections). Furthermore, the seal 205 is made of an elastic material. Therefore, the influence of contact between the front mass 225 and the seal 205 is small.

[0046] The through-hole 214 for the front mass 225 is formed in a cylindrical shape by combining the cleaning tank 202 and the upper block 203. Depending on the shape of the ultrasonic transducers 201A and 201B used, a slope or step may be provided at the base of the through-hole 214. A substantially uniform gap is formed between the wall surface of the through-hole 211 and the ultrasonic transducers 201A and 201B. The seal 205 is positioned near the base of the cylindrical part to prevent liquid leakage from the through-hole 211. As a result, the tip portion of the front mass 225, which deforms significantly when the ultrasonic transducers 201A and 201B are driven, can transmit vibrations to the liquid in the liquid storage section 213 without its deformation being hindered and without contact with the wall surface of the through-hole 211.

[0047] Furthermore, the liquid injected through the opening 212 can be filled into the liquid reservoir 213 up to the bottom surface of the cover 216. This ensures that the gap formed around the cylindrical portion of the front mass 225 inserted into the through hole 211 is filled with liquid. For reasons to be described later, the ultrasonic cleaning effect according to this disclosure can be obtained even if the liquid level is above the cover 216.

[0048] When liquid is injected into the liquid reservoir 213, the tip surface 215 of the front mass 225 is submerged in the liquid. In this state, the two ultrasonic transducers 201 are driven to irradiate the liquid with ultrasound from the tip surface 215. It is desirable that the upper end of the tip surface 215, which is the part that irradiates ultrasound, be approximately 0.5 to 1 mm above the liquid surface. By arranging it in this way, only the part of the sample nozzle that is immersed in the liquid can be intensively cleaned. In other words, it is desirable that the distance between the lower surface of the cover 216 and the upper end of the tip surface 215 be approximately 0.5 to 1 mm.

[0049] If the tip surface 215 is positioned deep below the liquid surface, the cleaning area will be further away from the liquid surface, requiring the sample nozzle to be inserted deeply into the liquid to clean the tip of the sample nozzle. This configuration increases the area of ​​the sample nozzle that gets wet. Since the sample nozzle is designed to ensure dispensing accuracy by limiting the area that gets wet, it is desirable to avoid wetting a wide area. For this reason, it is desirable to provide the cleaning area near the liquid surface.

[0050] Figure 2D is a front view showing the cleaning section of Figure 2A.

[0051] In the cleaning unit 200 shown in Figure 2D, an upper block 203 is connected to the top of the cleaning tank 202. The upper block 203 may consist of two or more parts. By sandwiching the cover 216 between these two or more parts, the cover 216 is integrated with the upper block 203, making it easier to remove and attach the upper block 203 when cleaning the cleaning tank 202.

[0052] Figure 2E is a side view showing the cleaning section of Figure 2A.

[0053] In Figure 2E, the flange 204 is circular, but to fit within the size of the cleaning tank 202, it may be partially machined to a shape other than circular.

[0054] Figure 2F is a perspective view showing the cleaning section of Figure 2A.

[0055] The upper surface of the upper block 203 is provided with a through hole 211 and an opening 212 for supplying liquid, both of which can be accessed from above. In other words, cleaning liquid can be supplied through the opening 212, and a sample nozzle can be inserted into the through hole 211.

[0056] Figure 2G is a side view showing the cleaning section of Figure 2A with the upper block 203 removed.

[0057] Figure 2H is a perspective view showing the cleaning section of Figure 2A with the upper block 203 removed.

[0058] As shown in Figure 2H, by removing the upper block 203, the front mass 225 of the ultrasonic transducer 201 is exposed, allowing for internal cleaning. When cleaning, if the cover 216 is fixed to the upper block 203 as described above, the cover 216 can also be removed at the same time, improving ease of operation during cleaning. Furthermore, the inside of the cleaning tank 202 can be cleaned by directly applying running water such as tap water to remove dirt.

[0059] Furthermore, as shown in Figure 2F, the upper block 203 is provided with two openings 212 and a through hole 211. This allows for simple cleaning of the interior, for example, even if running tap water is directly poured into one opening 212, the water will drain out through the other openings 212 and the through hole 211. In other words, it is possible to perform cleaning with the upper block 203 attached during daily cleaning without removing it, and to remove the upper block 203 only once every few weeks for periodic cleaning to clean the interior.

[0060] Furthermore, although not shown in the diagram, since the cleaning unit 200 is directly exposed to running water, electrical components such as the ultrasonic transducer 201 need to be protected with a cover or similar to ensure waterproofing. For example, in the configuration of the cleaning rack 30 shown in Figure 1, the cleaning unit 200 is enclosed in a case, so the ultrasonic transducer 201 is covered and does not get directly wet with water.

[0061] Furthermore, it is desirable that the dimensions of the cleaning unit 200 fit within the rack 24. By having such dimensions, the cleaning unit 200 can be moved to the position of the sample nozzle 22 and cleaned.

[0062] In this embodiment, the case where there is one upper block 203 is shown, but the ultrasonic cleaning machine of this disclosure is not limited to this. For example, if the upper block 203 is divided into two, and one opening 212 is provided in each upper block, and a gap is left between the two upper blocks, the gap can be used as a substitute for the through hole 211, and it is not necessary to provide the through hole 211. In this case, the cover 216 can be sandwiched between either of the two upper blocks and the cleaning tank 202.

[0063] Next, we will describe the state of the ultrasonic waves irradiated into the liquid from the tip of the front mass 225 of the ultrasonic transducer 201.

[0064] Figure 3A is a schematic diagram showing the sound pressure distribution and flow velocity generated at the front mass tip of an ultrasonic cleaner when no cover is provided for the cleaning tank.

[0065] Figure 3B is a schematic diagram showing the sound pressure distribution and flow velocity generated at the front mass tip of an ultrasonic cleaner when a cover is provided for the cleaning tank.

[0066] In these diagrams, the arrows represent vectors indicating liquid flow, with thicker arrows indicating the areas with the highest flow velocity. The dotted semicircles indicate regions with high sound pressure.

[0067] Acoustic analysis has shown that by driving the ultrasonic transducer 201 at its resonant frequency, liquid flow occurs in the direction of the arrows from the tip surfaces 215A and 215B of the front masses 225A and 225B. In particular, in the configuration shown in Figure 3A, the thick arrows extending toward the liquid surface have been confirmed by experimental observations, which show that the liquid overflows to the outside of the cleaning tank 202 (a phenomenon in which a liquid column is formed). This phenomenon is the same even when only one ultrasonic transducer 201 is driven, and the effect of the cover 216, which will be described later, is the same even when there is only one ultrasonic transducer 201.

[0068] When the liquid surface agitates significantly due to the driving of the ultrasonic transducer 201, the area of ​​the sample nozzle 22 that is wetted increases, potentially bringing the cleaning water into other samples or causing the liquid level detection sensor built into the sample nozzle 22 to malfunction. Furthermore, if the liquid overflows from the cleaning tank 202, wetting the transport line 25 and its surroundings is also a problem. Additionally, if the cleaning solution overflows, the liquid level drops, and the tip of the ultrasonic transducer 201 is exposed to the air, mist is generated. This mist wetting the surroundings and the sample nozzle 22 leads to the aforementioned problems.

[0069] In Figure 3B, the high-velocity flow portion indicated by the thick arrow collides with the cover 216 provided on the liquid surface, thus preventing overflow. It is desirable to cover a range of approximately 60 to 90 degrees with respect to the central axis of the front masses 225A and 225B, with the center of the tip surface (the point where the central axis of the front masses 225A and 225B intersects with the tip surfaces 215A and 215B) as the origin, and even more desirable to cover a range of approximately 50 to 90 degrees. This prevents overflow due to the generation of liquid columns. In particular, immediately after the ultrasonic transducer 201 starts operating, a strong water flow is generated, temporarily raising the liquid level around the cleaning holes 210. If the liquid level exceeds the cover 216, liquid remains on the upper surface of the cover 216, reducing the liquid volume in the cleaning tank 202 and potentially causing mist.

[0070] In this embodiment, the cover 216 is not fixed, and the cover 216 can move in accordance with the up and down movement of the liquid. Therefore, it is possible to absorb the temporary rise in liquid and prevent the liquid from overflowing after the ultrasonic transducer 201 is driven.

[0071] Furthermore, in addition to the cover 216, the opening 212 shown in Figure 2F is located in a region where the amplitude of the ultrasonic transducer 201 is smaller than that of the tip, and is situated in a region where fluctuations in the liquid level due to the driving of the ultrasonic transducer 201 are minimal.

[0072] Conversely, providing the opening 212 also has the effect of absorbing fluctuations in flow velocity between the tip surfaces 215A and 215B. For example, if there is no opening 212, when the pressure rises in the cleaning tank 202, the only area from which the pressure can be released is through the cleaning hole 210, so fluctuations in the liquid level around the cleaning hole 210 are concentrated. However, by providing the opening 212, there are multiple areas from which the pressure can escape, resulting in the effect of dispersing fluctuations in the liquid level at the cleaning hole 210.

[0073] As described above, by suppressing the strong flow velocity portion generated from the tip surfaces 215A and 215B of the front masses 225A and 225B, and preventing liquid from overflowing from the cleaning tank 202, cleaning can be performed without wetting the area outside the cleaning range of the sample nozzle 22 or the transport line 25.

[0074] In this embodiment, the effect of the cover 216 was explained with a configuration that floats on the liquid surface, but similar effects can be obtained with a cover that covers the aforementioned range, for example, a cover that opens and closes with an actuator. For example, an opening and closing mechanism may be used in which the cover is open before the sample nozzle 22 passes through and closes after insertion. Examples of such structures include the lens cover mechanism of a digital camera.

[0075] Figure 4 is a top view showing an example of the arrangement of covers in the cleaning tank of the embodiment.

[0076] This figure shows an example of the relationship between the cover 216 and the wall surface of the washing tank 202.

[0077] As mentioned above, the cover 216 is not fixed to the cleaning tank 202. Furthermore, in order to suppress restraint by the surface tension of the liquid, it is desirable to provide a protrusion 410 on the inner wall surface of the cleaning tank 202, as shown in this figure, to reduce the contact area with the cover 216.

[0078] If the gap between the wall of the cleaning tank 202 and the cover 216 is too large, the position of the cleaning hole 210 may shift significantly due to fluctuations in the liquid level, increasing the risk of the sample nozzle 22 coming into contact with the cover 216 when inserting it. Therefore, it is desirable to design the size of the gap between the wall of the cleaning tank 202 and the cover 216 taking into consideration the outer diameter and stopping accuracy of the sample nozzle 22, as well as the shape and dimensions of the cleaning hole 210.

[0079] Figure 5 is a configuration diagram showing an example of a cleaning rack having an ultrasonic cleaning machine according to this embodiment.

[0080] As shown in this figure, the cleaning rack 30 comprises a cleaning unit 200, an ultrasonic transducer control unit 301, a drive power supply 302 (battery), and a transport base 303. The ultrasonic transducer control unit 301 controls the driving of the ultrasonic transducers 201A and 201B (Figure 2A).

[0081] The ultrasonic transducer control unit 301 generates a sine wave at the resonant frequency of the ultrasonic transducers 201A and 201B to drive the ultrasonic transducer 201. The ultrasonic transducer control unit 301 also includes an impedance matching circuit to increase the drive current of the ultrasonic transducer 201 and amplify its amplitude, as well as a circuit for automatic tracking of the resonant frequency.

[0082] The power supply 302 is a rechargeable battery that is charged each time the washing rack 30 is used. The washing time for the sample nozzles 22 is in the range of a few minutes or less, and there is no need for long operating times, so a small battery is sufficient. The power supply 302 may be configured to be charged by installing a wireless power supply unit at a predetermined location adjacent to the transport line 25.

[0083] The transport base 303 has the same shape as the bottom of the rack 24 used for the sample containers 23. Therefore, there is no need to change the hardware of the transport line 25. The cleaning rack 30, which includes the cleaning unit 200, the ultrasonic transducer control unit 301, and the drive power supply 302, is smaller than or equal to the size of the rack 24 when the conventional sample containers 23 are installed.

[0084] The cleaning section 200 is covered by a cover 304. The cover 304 prevents liquid from coming into contact with electrical components such as the piezoelectric element 207 and the electrode 208 when supplying or discharging liquid to the opening 212 using a pipette or the like.

[0085] As mentioned above, since the ultrasonic transducer 201 is sealed at the vibration nodes, the vibration amplification efficiency is increased. Furthermore, by positioning the tip surface 215 of the ultrasonic transducer 201 close to the side surface of the sample nozzle 22, strong ultrasonic waves can be irradiated onto the sample nozzle 22, thereby improving the cleaning effect. In addition, by irradiating ultrasonic waves from two directions, a configuration is achieved that allows cleaning even in narrow spaces such as a small cleaning rack 30.

[0086] The amount of cleaning solution required for cleaning varies depending on the size of the storage section 213, but is generally between several hundred μL and several mL. While water can be used as the cleaning solution, a mixture of water and detergent, or detergent itself, may also be used.

[0087] As described above, the automated analyzer according to this disclosure has a configuration that uses the ultrasonic cleaning machine of this embodiment by transport.

[0088] Figure 6 is a flowchart showing the method for cleaning the dispensing nozzle using an ultrasonic cleaner in this embodiment.

[0089] As shown in the figure, the cleaning solution is injected through the opening 212 of the cleaning section 200 (step S601). This fills the storage section 213 with the cleaning solution. At this time, by using a specially sized container that does not hold more liquid than the capacity of the storage section 213, the liquid level can be injected without exceeding the cover 216. Alternatively, the pipette's dispensing volume may be set to the same amount as the capacity of the storage section 213 for injection.

[0090] As mentioned above, in order to avoid wetting areas other than the cleaning range of the sample nozzle 22, it is undesirable to inject liquid beyond the cover 216. Therefore, it is desirable to use a method that allows injection of the same amount of liquid as the capacity of the liquid reservoir 213.

[0091] After the liquid is injected, the washing rack 30 is placed on the transport line 25 (step S602). Then, under the control of the automatic analyzer 10, it is transported to the washing position (step S603), and the automatic washing operation is started.

[0092] The washing rack 30 has a built-in communication function, which will be described later, and can be started by an instruction from the control unit of the automatic analyzer 10. After stopping at the washing position, ultrasonic driving is started (step S604).

[0093] Here, steps S601 to S603 can be performed manually, but they can also be performed automatically using a washing solution dispensing unit installed in the automatic analyzer 10. In this case, when a command signal to start the automatic washing function is sent from the terminal of the automatic analyzer 10, as in step S604, the washing rack 30 is automatically installed on the transport line 25, and the washing solution is automatically injected into the liquid storage section 213 of the washing section 200.

[0094] When transporting a standard rack 24, the barcode attached to the side of the rack 24 is read to branch the subsequent analysis and transport process. Therefore, by attaching a barcode to the washing rack 30 in the same position as the standard rack 24, the automatic analyzer 10 can distinguish between the rack 24 used for inspection and the washing rack 30 used for washing, and perform the maintenance operation for washing.

[0095] After transporting the washing rack 30 to near the sample nozzle 22, the sample nozzle 22 is lowered toward the liquid storage section 213 (step S605), and the tip of the sample nozzle 22 is immersed in the washing solution for a certain period of time to perform washing (step S606). After washing is complete, the sample nozzle 22 is raised, and then the washing rack 30 is removed (step S607). The ultrasonic drive is stopped (step S608) by instruction from the control unit of the automatic analyzer 10 using the aforementioned communication function. By incorporating a timer function, it is also possible to stop after a certain period of time has elapsed.

[0096] Then, the washing rack 30 is transported to a location for retrieval (process S609), and the washing rack is retrieved and cleaned (process S610). As mentioned above, cleaning can be done by flowing water through the opening 212 of the upper block 203, or by removing the upper block 203 and cleaning it.

[0097] If necessary, the cleaning solution may be replaced, and another sample nozzle 22 may be cleaned continuously. If cleaning is not performed, the cleaning solution is drained and the process is terminated.

[0098] Figure 7 is a graph showing an example of a driving pattern for two ultrasonic transducers.

[0099] This figure shows the period from when the sample nozzle 22 begins to descend toward the liquid storage section 213 until it finishes rising.

[0100] The ultrasonic transducers A and B, which are started to operate using the method described above, are repeatedly operated before or simultaneously with the descent of the sample nozzle 22. In this case, a certain time difference between the operation of ultrasonic transducers A and B and the descent of the sample nozzle 22 is acceptable.

[0101] In this driving pattern, it is desirable to drive ultrasonic transducers A and B with the same output. The control circuit outputs a single drive signal for the transducers, which is then branched and output to ultrasonic transducers A and B. In this case, the ultrasonic transducer control unit 301 either automatically tracks the resonant frequency of either ultrasonic transducer A or B, or drives them at a frequency near (or midway between) the resonant frequencies of the two ultrasonic transducers A and B. To drive them at a frequency near the resonant frequencies of the two ultrasonic transducers A and B, there are two methods: determining the drive frequency from a frequency measured in advance, or adding a circuit to detect the resonant frequency during driving and changing it as needed.

[0102] Because ultrasonic transducers A and B have simple shapes, the variation in their resonant frequencies due to manufacturing and assembly is small. Therefore, if the driving frequency is near the resonant frequency of the two ultrasonic transducers A and B, the two ultrasonic transducers A and B can be driven with a large amplitude.

[0103] As mentioned above, the cover 216 suppresses the strong flow velocity portion generated from the tip surface 215 after the ultrasonic transducers A and B are started to move, preventing the liquid from overflowing from the cleaning tank 202. Therefore, the liquid level stabilization time is shortened, and the time from the start of operation of ultrasonic transducers A and B to the end of nozzle descent can be reduced. In other words, stable cleaning is possible even if the operation of ultrasonic transducers A and B is started immediately before insertion of the sample nozzle 22.

[0104] Figure 8 is a diagram showing the configuration of an automated analyzer that corresponds to the case where an ultrasonic cleaning machine built into the transport rack of this embodiment is used.

[0105] In this figure, the automated analyzer is controlled by the automated analyzer control unit 801. The user of the automated analyzer can issue instructions for analysis and cleaning processes from the graphical user interface 802 (GUI). Normal analysis and the cleaning maintenance mode in this embodiment are performed by the maintenance control means 803, which controls the sample dispensing mechanism 15 and the transport line 25.

[0106] The sample dispensing mechanism 15 controls the position of the sample nozzle 22 via the dispensing arm horizontal movement means 805 (dispensing arm horizontal movement unit) and the dispensing arm vertical movement means 806 (dispensing arm vertical movement unit) from the dispensing arm control means 804 (dispensing arm control unit). In maintenance mode, the horizontal and vertical positions of the sample nozzle 22 are controlled so that the cleaning range of the tip of the sample nozzle 22 is immersed in the liquid in the liquid storage section 213. That is, it is positioned to a depth in which the object to be cleaned is immersed in the cleaning solution. The horizontal position of the sample nozzle 22 is preferably at an intermediate position between the two tip surfaces 215, but it is also possible to control it by moving it horizontally while immersed, bringing it closer to tip surface 215A or tip surface 215B. The transport line 25 is driven from the rack transport control means 807 (rack transport control unit) via the rack transport means 808 (rack transport unit).

[0107] The washing rack 30 has, independently of the automatic analyzer control unit 801, a communication means 821 for communicating with the automatic analyzer, a transducer driving means 822 (transducer driving unit) for detecting and driving the resonance frequency of the ultrasonic transducer 201, and a power management means 823 for managing the status of the drive power supply 302.

[0108] As described above, the communication means 821 controls the start and end of the ultrasonic transducer 201 driven by the transducer driving means 822 based on instructions from the automatic analyzer 10.

[0109] The power management means 823 manages the charging status of the drive power supply 302 and displays it by changing the color of an LED provided on the washing rack 30, or by communicating the status to an external party via the communication means 821.

[0110] With the above configuration, the cleaning rack 30 is transported to a position on the transport line 25 where the sample nozzle 22 can access it, the ultrasonic transducer 201 mounted on the cleaning rack 30 is started, and the sample nozzle 22 is immersed in the liquid reservoir 213, thereby cleaning the cleaning area of ​​the sample nozzle 22.

[0111] Furthermore, the reagent nozzle 21 can also be implemented with a similar configuration if it has access to the transport line 25.

[0112] In this embodiment, the case in which the reagent nozzle 21 and the sample nozzle 22 are provided separately is described, but in some analytical instruments, the dispensing of reagents and samples may be performed using a single shared nozzle. Even in such instruments, the nozzle is washed with a stream of water each time reagents or samples are dispensed, but daily maintenance is necessary, and dispensing accuracy can be maintained by performing ultrasonic cleaning as disclosed herein.

[0113] Furthermore, according to this disclosure, the cover can be easily attached and detached while the ultrasonic transducer is installed.

[0114] In the above-described embodiment, a configuration is described in which the tip surfaces 215A and 215B of two ultrasonic transducers 201A and 201B are arranged facing each other. However, the ultrasonic cleaning machine of this disclosure is not limited to this configuration and also includes cases in which a single ultrasonic transducer is installed horizontally.

[0115] The following describes preferred embodiments related to this disclosure.

[0116] Multiple ultrasonic transducers are installed on the side of the cleaning tank.

[0117] The liquid storage section allows for the insertion of the dispensing nozzle to be cleaned, and the cover is provided with a cleaning hole having an inner diameter larger than the outer diameter of the dispensing nozzle.

[0118] The cover has a limited horizontal range of motion to maintain separation from the dispensing nozzle inserted into the irrigation hole.

[0119] The washing tank is equipped with an upper block that covers the front manhole, and the upper block has an opening for pouring liquid into the storage section.

[0120] The upper block is provided with a cleaning opening for inserting the dispensing nozzle.

[0121] The cover has its origin at the center of the front surface, which is the point where the central axis of the front mass intersects the front surface of the front mass, and covers a range from 60 degrees to 90 degrees with respect to the central axis of the front mass.

[0122] The liquid injection opening in the upper block is located between the front surface of the front mass and the through hole into which the front mass is inserted.

[0123] The upper block is designed to be removable from the washing tank, exposing the front mass.

[0124] The cover is made of resin or metal.

[0125] The cleaning tank is fitted with an upper block that covers the front mass. The upper block is provided with two injection openings for pouring liquid into the storage section and a cleaning opening for inserting a dispensing nozzle. The cleaning opening is located between the two injection openings.

[0126] The inner wall surface of the washing tank is provided with protrusions that come into contact with the cover.

[0127] The automated analyzer has a mechanism that transports an ultrasonic cleaner on a conveyor line to clean the dispensing nozzles. [Explanation of symbols]

[0128] 10: Automatic analyzer, 11: Reagent container, 12: Reagent disc, 13: Reaction disc, 14: Reagent dispensing mechanism, 15: Sample dispensing mechanism, 21: Reagent nozzle, 22: Sample nozzle, 23: Sample container, 24: Rack, 25: Conveyor line, 26: Cell, 27: Washing tank, 30: Washing rack, 201, 201A, 201B: Ultrasonic transducer, 202: Washing tank, 203: Upper block, 204: Flange, 205: Seal, 207: Piezoelectric element, 208: Electrode, 209: Fastening bolt, 210: Washing hole, 211: Through hole, 212: Opening, 213: Liquid reservoir Parts 215, 215A, 215B: Tip surface, 216: Cover, 225: Front mass, 226: Back mass, 301: Ultrasonic transducer control unit, 302: Drive power supply, 303: Transport base, 304: Cover, 801: Automatic analyzer control unit, 802: Graphical user interface, 803: Maintenance control means, 804: Dispensing arm control means, 805: Dispensing arm horizontal movement means, 806: Dispensing arm vertical movement means, 807: Rack transport control means, 808: Rack transport means, 821: Communication means, 822: Transducer drive means, 823: Power management means.

Claims

1. A washing tank having a liquid storage section for storing liquid, Includes an ultrasonic transducer having a piezoelectric element and a front mass, The side surface of the washing tank is provided with through holes having openings in the outer wall surface of the washing tank and the inner wall surface of the liquid storage section. The front mass is inserted into the through hole. A cover is installed so as to cover the upper part of the front end surface of the aforementioned front mass. The cover is movable at least upward, in an ultrasonic cleaning machine.

2. The ultrasonic cleaning machine according to claim 1, wherein a plurality of ultrasonic transducers are installed on the side surface of the cleaning tank.

3. The liquid storage section is capable of inserting the dispensing nozzle to be cleaned. The ultrasonic cleaning machine according to claim 1, wherein the cover is provided with a cleaning hole having an inner diameter larger than the outer diameter of the dispensing nozzle.

4. The ultrasonic cleaning machine according to claim 3, wherein the cover has a limited horizontal range of motion so as to maintain a state of separation from the dispensing nozzle inserted into the cleaning hole.

5. The washing tank is equipped with an upper block that covers the front mass, The ultrasonic cleaning machine according to claim 3, wherein the upper block is provided with an injection opening for pouring liquid into the liquid storage section.

6. The ultrasonic cleaning machine according to claim 5, wherein the upper block is provided with a cleaning opening for inserting the dispensing nozzle.

7. The ultrasonic cleaning machine according to claim 4, wherein the cover covers a range from 60 degrees to 90 degrees with respect to the central axis direction of the front mass, with the center of the front surface, which is the point where the central axis of the front mass intersects the front surface of the front mass, as the origin.

8. The ultrasonic cleaning machine according to claim 5, wherein the liquid injection opening of the upper block is provided between the front surface of the front mass and the through hole into which the front mass is inserted.

9. The ultrasonic cleaning machine according to claim 5, wherein the upper block is configured to be removable from the cleaning tank to expose the front mass.

10. The ultrasonic cleaning machine according to claim 1, wherein the cover is made of resin or metal.

11. The washing tank is equipped with an upper block that covers the front mass, The upper block is provided with two injection openings for pouring liquid into the liquid storage section and a cleaning opening for inserting the dispensing nozzle. The ultrasonic cleaning machine according to claim 3, wherein the cleaning opening is provided between the two liquid injection openings.

12. The ultrasonic cleaning machine according to claim 1, wherein the inner wall surface of the cleaning tank is provided with a protrusion that contacts the cover.

13. Having the ultrasonic cleaning machine described in claim 1, An automated analyzer having a mechanism for transporting the aforementioned ultrasonic cleaner on a transport line and cleaning the dispensing nozzle.

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