JP3559159B2 - Medium dispensing device and dispensing method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a medium dispensing apparatus and method for injecting a medium such as an agar medium used for various microbial tests into a dispensing container at an appropriate temperature while preventing local gelation and contamination by various bacteria. It is about.
[0002]
[Prior art]
In general, it relates to GMP validation (Good Manufacturing Practice Validation) such as, for example, sterility test, preservation efficacy test, bacterial count limit test, environmental drop bacteria test, antibiotic titer (efficacy) measurement, and body fluid concentration measurement in the pharmaceutical industry. For example, a microbial test such as an agar medium is used for a microbial test to be performed, for example, a viable cell count test, a fungal count test in the food industry, a microbial test related to a countermeasure against harmful bacteria based on Hasep (HACCP: Azad Analysis Critical Control Point), and the like. Is widely used. Microorganism tests of this type are roughly classified into a qualitative test and a quantitative test. In the quantitative test, an agar medium is almost always used.
[0003]
Usually, the medium is injected into a petri dish, and then is provided in a state where the medium is extended into a plate having a uniform thickness. Depending on the test, the medium previously injected into the petri dish may be spread into a flat plate to form a base medium, and then the medium may be further dispensed onto the solidified base medium to form an overlay medium.
When injecting the culture medium into the petri dish, it goes without saying that the injection amount is not only accurate, but also the medium temperature at the time of injection is properly controlled to prevent local gelation, bubbles and It is also very important to prevent contamination by various bacteria.
[0004]
For example, the solidification temperature of a medium is usually higher than room temperature (for example, 24 ° C.). In the case of a solid medium, solidification starts at 38 ° C. and solidifies completely at 36 ° C. Therefore, unless the medium before being poured into the petri dish is heated to a solidification temperature or higher and kept in a liquid state, the medium cannot be evenly spread on the poured petri dish. However, if the temperature is too high, it takes too much time to solidify, or the bacteria and microorganisms used in the test are killed.
Therefore, it is important that the medium is adjusted and managed at an appropriate temperature that is higher than the solidification temperature and not higher than necessary, and that the medium is quickly injected into the petri dish.
In addition, if air bubbles are mixed in the medium, small air bubbles may be mistaken for bacteria at the time of measurement, and it is important to prevent air bubbles from being mixed in order to prevent a decrease in measurement accuracy due to an erroneous reading.
[0005]
As described above, the operation of dispensing the culture medium into the petri dish has a number of severe conditions, and a high degree of skill is required to perform the operation manually. Therefore, automation of the medium dispensing operation is required so that the medium dispensing operation can be performed efficiently without skill.
From such a background, conventionally, for example, a medium container for storing a medium, a stirring means for stirring the medium in the medium container, a heating means for heating and adjusting the medium in the medium container to a desired temperature, A nozzle for injecting a culture medium into a Petri dish, which is an injection container, a medium flow path that guides the medium in the medium container to the nozzle, and a dispensing pump that sequentially sends the medium in the culture medium to the medium flow path, There have been proposed various medium dispensing apparatuses having a configuration including a stirring device, a heating adjusting device, and a control device for controlling operation of a dispensing pump.
[0006]
[Problems to be solved by the invention]
However, in the medium dispensing device having the above-described configuration, even when the medium temperature in the medium container is adjusted to the optimum value by the stirring means or the heating means provided in the medium container, at the start of operation or when the dispensing interval is greatly increased. Since the temperature of the culture medium channel from the culture medium container to the nozzle is considerably lower than the temperature of the maintained medium, the temperature of the culture medium fed to the culture medium flow path decreases due to heat absorption by the culture medium flow path. It was difficult to dispense at the temperature.
[0007]
Therefore, at the start of operation, etc., there is a method in which the heated medium is continued to flow until the temperature of the medium flow path from the medium container to the nozzle rises to an appropriate temperature.However, in such a method, a large amount of medium is wasted. Become.
[0008]
Furthermore, immediately before the start of the next dispensing operation, a treatment for discarding the medium remaining in the nozzle or the like and exposed to the outside air is performed in order to prevent air bubbles and various bacteria from being mixed. It is difficult to control the discharge amount of the culture medium to a minimum only by the operation control using the injection pump, which causes a problem that the culture medium is wasted.
[0009]
The present invention has been made in view of such a conventional problem, and a medium dispensing method that can stably maintain the entire area of the dispensing flow path at an appropriate temperature and reliably perform dispensing of an appropriate temperature medium. It is a first object to provide an apparatus and a dispensing method.
It is a second object of the present invention to provide a medium dispensing apparatus and a dispensing method capable of reliably preventing air bubbles and various bacteria from being mixed with a minimum amount of medium disposal.
Furthermore, by supplementing the medium filtered by the filter with only the volume of the medium reduced by the dispensing into the medium container, the sterile state of the medium is always maintained, and the dispensing can be performed more reliably in the sterile state. A third object is to provide a medium dispensing apparatus and a dispensing method.
[0010]
[Means for Solving the Problems]
To achieve the above object, the medium dispensing apparatus according to the present invention is a medium dispensing apparatus that injects a medium stored in a medium container equipped with a heat retaining and stirring device into the dispensing container, wherein the medium in the medium container is A medium delivery channel that serves as a medium channel leading to a nozzle to be injected into the dispensing container, and one end is branched and connected in the middle of the medium delivery channel, and the other end is connected to the medium container to transfer the medium. A culture medium return flow path serving as a culture medium flow path for returning to the culture medium container, and a culture medium supply flow path which is disposed upstream of a branch position of the culture medium return flow path with the culture medium return flow path, A dispensing pump, a first opening / closing valve disposed in the middle of the medium sending flow path and downstream of the branch position to open and close the medium sending flow path, and the medium return flow path. On the way downstream of the branch position, A second on-off valve to be closed; an auxiliary heating means for heating and adjusting the culture medium in the culture medium delivery channel to a desired temperature in a section downstream of the branch position of the culture medium delivery channel; and the dispensing pump. , An auxiliary heating means, and a control device for controlling operation of the first and second on-off valves.
Here, it is desirable that the auxiliary heating means is an infrared lamp. In addition, it is desirable to provide a filter at the upper part of the culture medium container to replenish the sterile air into the culture medium container.
[0011]
And the medium dispensing method according to the present invention for achieving the above object is a medium dispensing method for injecting a predetermined amount of medium into a dispensing container using the medium dispensing apparatus according to the present invention, The culture medium sending flow path and the culture medium return flow path from the culture medium container to the branch position closed the first opening / closing valve and opened the second opening / closing valve at the time of dispensing standby operation, so that the temperature inside the culture medium container was maintained. While the culture medium is circulated by the dispensing pump to maintain the culture medium at an appropriate temperature, the culture medium delivery channel in the section from the branch position to the nozzle is configured to maintain the culture medium at an appropriate temperature by heating by the auxiliary heating means. did.
[0012]
According to the above configuration, the culture medium delivery flow path and the culture medium return flow path from the culture medium container to the branch position are heated in the culture medium container by closing the first open / close valve and opening the second open / close valve during the standby operation. The medium is maintained at an appropriate temperature by circulation. On the other hand, the culture medium delivery flow path in the section from the branch position of the culture medium return flow path to the nozzle is maintained at an appropriate temperature by heating by the auxiliary heating means.
[0013]
In the culture medium dispensing device according to the present invention, the nozzle is a nozzle that allows advance and retreat between a predetermined dispensing position A and a standby position B deviating from the dispensing position A. Preferably has a function of controlling the advance / retreat operation of the nozzle.
Then, as a culture medium dispensing method in that case, during the dispensing standby operation, the state where the nozzle is retracted to the standby position B is maintained, the second on-off valve is closed immediately before the start of the dispensing operation, and the second dispensing operation is performed. It is preferable that the dispensing pump be operated for a predetermined period of time with the on-off valve open to discharge the culture medium at the nozzle tip whose quality has become inappropriate at the standby position B.
As a result, the medium that has come into contact with the outside air at the tip of the nozzle is discarded, so that aseptic dispensing can be performed without bubbles.
Further, the method for dispensing culture medium by the culture medium dispensing apparatus according to the present invention including a filter for replenishing sterile air into the culture medium container includes a culture medium delivery flow path from the culture container to the branch position and a return of the culture medium. The flow path closes the first on-off valve and opens the second on-off valve during the dispensing standby operation to circulate the medium in the medium container by the dispensing pump to maintain the medium in an aseptic state, It is desirable to replenish the sterile air into the medium container via the filter at the time of dispensing.
Thereby, the medium in the medium container and the medium flow path can always be stably maintained in an aseptic state.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a medium dispensing apparatus and a dispensing method according to the present invention will be described in detail with reference to FIGS. 1 and 2.
FIG. 1 shows a schematic configuration of an embodiment of a medium dispensing apparatus according to the present invention, and FIG. 2 is a flowchart showing a processing procedure of a medium dispensing method performed by the medium dispensing apparatus of the present invention.
[0015]
As shown in FIG. 1, the medium dispensing device 1 of the present embodiment includes a medium container 3 for storing a medium 2 such as an agar medium, a stirring unit 5 for stirring the medium 2 in the medium container 3, and a medium container 3. Heating means 6 for heating and adjusting the medium 2 in the inside to a desired temperature, a nozzle 7 for injecting the medium 2 into the dispensing container, and the nozzle 7 is removed from a predetermined dispensing position A and the dispensing position A A nozzle moving means 9 for moving between the standby position B, a culture medium delivery tube 11 as a culture medium delivery flow path serving as a culture medium flow path for guiding the culture medium 2 in the culture medium container 3 to the nozzle 7, A three-pronged pipe joint 12 for branch connection, which is provided in the middle, and one end is branched and connected to the culture medium delivery tube 11 via the three-pronged pipe joint 12 and the other end is connected to the culture vessel 3 to transfer the culture medium 2 to the culture vessel. Culture medium as a medium return channel that becomes the medium channel to return to 3. The return tube 14 and the culture medium 2 in the culture vessel 3 are sequentially provided on the culture medium transmission tube 11 on the upstream side of the branch position C of the culture medium return tube 14 (that is, the position of the three-pronged joint 12). Pump 15, which feeds the medium 2; an auxiliary heating means 16 for heating and adjusting the medium 2 in the medium sending tube 11 to a desired temperature in a section downstream of the branch position C of the medium sending tube 11; A first opening / closing valve 18 provided downstream of the branch position C to open and close the flow path of the medium delivery tube 11; and a medium return mounted on the medium return tube 14 downstream of the branch position C. A second opening / closing valve 19 for opening and closing the flow path of the tube 14, and a container for loading / unloading a petri dish 21, which is a dispensing container for receiving dispensing of the culture medium 2 from the nozzle 7, to a dispensing position A through a predetermined route. And feed means 23, and a, and a control device (not shown) that controls the operation of each component described above.
[0016]
The heating means 6 is heated by a ring-shaped heater 6b provided at the inner bottom of a heating tank 6a for bathing the culture medium container 3 in water. The amount of heating by the ring-shaped heater 6b is set by monitoring the temperature of the medium container 3 and the like so that the medium 2 in the medium container 3 has an appropriate temperature, and is controlled by a temperature control device (not shown).
[0017]
The stirring means 5 includes a medium stirring rotor 5a submerged in the medium container 3, a medium stirring rotor 5b submerged at the inner bottom of the heating tank 6a, and a noncontact magnetic rotor. And a magnetic control unit 5c for simultaneously controlling the rotation of both by means of a dynamic means. By controlling the amount of rotation of each rotor 5a, 5b, the stirring intensity is adjusted.
[0018]
In the case of the present embodiment, the nozzle moving means 9 is a direct-acting hydraulic cylinder in which the distal end of the telescopic rod 9a is connected to the nozzle 7.
In addition, a silicon tube having excellent elasticity and durability is used for each of the tubes 11 and 14.
[0019]
The dispensing pump 15 has a known structure in which the medium in the tube is pushed out by a group of rotating rollers, and controls the amount of rotation of a table supporting the group of rollers to adjust the amount of medium discharged. In particular, in a channel system requiring sterility, the dispensing pump having such a configuration is effective in preventing contamination of various bacteria.
The auxiliary heating means 16 uses an infrared lamp in the present embodiment. In the infrared lamp, the heat generation amount, the separation distance, and the like are set in advance so that the culture medium delivery tube 11 has an appropriate temperature. Heating with an infrared lamp can perform substantially uniform heating as a whole without locally increasing the temperature as compared with other heating means. This is particularly effective when strict temperature control is required, such as death by temperature.
[0020]
Each of the on-off valves 18 and 19 is provided with a pair of holding members 25 and 26 so as to be able to advance and retreat in the radial direction of the tube, and closes the flow path by crushing the tube with the pair of holding members 25 and 26. In the figure, the first on-off valve 18 is open and the second on-off valve 19 is closed. The holding members 25 and 26 are driven by an actuator such as a solenoid.
The container transport means 23 transports the petri dish 21 at a predetermined interval and a predetermined speed by using a known traveling means or a moving mechanism. Normally, when the petri dish 21 arrives at the dispensing position A, the transport of the petri dish 21 is temporarily stopped until the dispensing operation is completed, and the dispensed petri dish 21 is rotated while being inclined so that the medium is evenly spread. However, when the transport speed is slow and the dispensing operation can be performed even while the transport is being performed, the petri dish 21 may be dispensed without stopping at the dispensing position A.
On the other hand, aseptic air is constantly replenished in the upper part of the medium container 3 through a disposable filter 27 in which a commercially available membrane filter and a folder are integrated. The disposable filter 27 sterilizes the outside air replenished into the medium container 3 at the time of dispensing the medium, prevents direct contact between the medium 2 and the outside air, and always keeps the medium 2 in a sterile state. .
[0021]
In the culture medium dispensing device 1, the control device (not shown) includes, specifically, the stirring means 5, the heating means 6, the nozzle moving means 9, the dispensing pump 15, the auxiliary heating means 16, the first and second opening / closing valves 19 , And the operation of the container transporting means 23 and the like, and the operation of each part is controlled by the procedure shown in FIG. 2 to implement the medium dispensing method according to the present invention. That is, the medium dispensing method of the present invention is performed by the control device that controls the operation of the medium dispensing device 1.
[0022]
Hereinafter, the procedure of the dispensing process realized by the control device will be described with reference to FIG.
When the operation of the medium dispensing apparatus 1 is started, first, in step 101, it is determined whether or not the dispensing operation to be performed is the first operation after the apparatus is started, and if it is determined that the operation is the second or subsequent operation. Go to step 201.
When the power switch of the medium dispensing device 1 is pressed, the stirring means 5, the heating means 6, and the auxiliary heating means 16 are automatically started to operate. Be started. The start of the transfer by the container transfer means 23 may be instructed by a dedicated switch.
[0023]
If it is determined in step 101 that this is the first time after the start of the apparatus, the process proceeds to step 201 after performing a preparation operation including steps 102 to 106 described below.
In step 102, the first on-off valve 18 is closed and the second on-off valve 19 is opened, and thereafter, the dispensing pump 15 is operated, and the medium 2 in the medium container 3 is removed from the medium container 3 and the medium delivery tube 11. It is circulated through a circulation channel formed by the section up to the branch position C and the medium return tube 14.
In step 103, the transport state of the petri dish 21 by the container transport means 23 is monitored, and it is determined by detecting whether or not the foremost petri dish 21 has reached just before the dispensing position A by a position sensor or the like (not shown). I do. If it has arrived, the operation of the dispensing pump 15 is stopped in the next step 104, and in the next step 105, the first switching valve 18 is opened and the second switching valve 19 is switched to a closed state. The dispensing pump 15 is operated again. The operation in step 105 is to discharge the old culture medium remaining in the section from the branch position C to the nozzle 7 at the standby position B, or to enter the flow path in the section from the branch position C to the nozzle 7 when the operation of the apparatus is stopped. It is for removing the air.
After completing the discharge of the improper residual medium and the release of the air in step 105, the process proceeds to the next step 106, in which the dispensing pump 15 is stopped. Then, the process proceeds to the next step 201.
[0024]
Step 201 is an operation in which the medium 2 in the medium container 3 and the medium in the circulation channel are kept at an appropriate temperature and waits for the actual dispensing operation. Specifically, the first on-off valve 18 Is closed and the dispensing pump 15 is operated with the second on-off valve 19 opened to circulate the medium 2 in the medium container 3. Due to the circulation of the culture medium, the culture medium 2 heated in the culture vessel 3 circulates while transferring heat to the circulation flow path, and the medium temperature in the entire circulation flow path and the culture medium temperature in the culture vessel are highly accurate. Is uniformed.
Then, as shown in step 202, it is determined whether or not the leading petri dish 21 has arrived at the dispensing position A. If the petri dish 21 has arrived at the dispensing position A, the operations of steps 301 to 304 are performed. Do. Step 301 is a step of switching the state of each of the on-off valves 18 and 19 from the medium circulation state performed in step 201 to discharge a small amount of medium remaining at the tip of the nozzle 7. Specifically, the first on-off valve 18 is opened and the second on-off valve is closed, and the dispensing pump 15 is stopped after a predetermined time has elapsed. By stopping the operation of the dispensing pump 15 while adjusting the switching timing of the on-off valves 18 and 19 at this time, the amount of the medium to be discharged can be minimized.
[0025]
In step 302, after the discharge of the medium for removing bubbles and various bacteria is completed, the dispensing pump 15 is stopped, and the nozzle 7 is moved from the standby position B to the dispensing position A.
When the nozzle 7 moves to the dispensing position A in step 303, the dispensing pump 15 is operated to inject an appropriate amount of the culture medium 2 into the petri dish 21. This step is a dispensing operation.
Next, in step 304, after the injection of the appropriate amount of medium is completed, the dispensing pump 15 is stopped, and the nozzle 7 is returned to the standby position B again. Then, after the end of step 304, the process returns to the first step 101.
[0026]
It is needless to say that the respective components of the medium dispensing apparatus are not limited to the present embodiment, and can be appropriately designed and changed.
[0027]
【The invention's effect】
As described above, according to the medium dispensing apparatus and the dispensing method of the present invention, the medium delivery flow path from the medium container to the branch position of the medium return flow path, and the medium return flow path are in a standby state for dispensing. The entire medium is heated and adjusted to an appropriate temperature by the medium in the circulating medium container, and the medium delivery channel from the branch point of the medium delivery channel to the medium return channel to the nozzle is heated and adjusted by the auxiliary heating means. Therefore, the entire medium flow path that guides the medium from the medium container to the nozzle is maintained at a uniform temperature state in which the medium temperature hardly decreases, so that the temperature of the medium to be sent is maintained at an appropriate temperature with high accuracy. It can be kept stable.
[0028]
Furthermore, in the medium container, aseptic outside air filtered by a filter is replenished only by the volume of the medium that is reduced at the time of dispensing, so that the air in contact with the medium in the medium container can always be maintained in a sterile state. It becomes. For this reason, it is possible to sterilize the entire medium flow path.
[0029]
Further, the medium dispensing apparatus of the present invention includes a nozzle capable of moving back and forth between a predetermined dispensing position A and a standby position B deviating from the dispensing position A, and the control device includes It is a configuration equipped with a function of controlling the movement operation. In this case, as a medium dispensing method, the state where the nozzle is retracted to the standby position B is maintained, and immediately before the start of the dispensing operation, the second on-off valve is closed. The dispensing pump is operated for a predetermined period in a state where the first closing valve is closed and the first opening / closing valve is opened, and the medium of inappropriate quality is discharged at the standby position B due to the remaining medium in the nozzle and the medium sending flow path. .
Therefore, even while the medium is being delivered by the dispensing pump, by closing the first on-off valve and opening the second on-off valve, the operation of discarding the medium can be performed without disturbing the operation of the dispensing pump. It can be stopped instantaneously, the amount of medium discharged for air removal and disposal of medium that comes in contact with the outside air can be minutely adjusted, and dispensing of inappropriate quality medium with minimal medium disposal Can be reliably prevented. Thus, the quality of the medium to be injected into the dispensing container at the time of dispensing can be maintained at a high level, uniformly and with good quality.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a medium dispensing apparatus according to the present invention.
FIG. 2 is a flowchart showing a processing procedure of a culture medium dispensing method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Culture medium dispensing apparatus 2 Medium 3 Medium container 5 Stirring means 6 Heating means 7 Nozzle 9 Nozzle moving means 11 Medium delivery tube 12 Three-pronged pipe joint 14 Medium return tube 15 Dispensing pump 16 Auxiliary heating means 18 First open / close valve 19 2 open / close valve 21 Petri dish (dispensing container)
23 Container transport means 27 Disposable filter A Dispensing position B Standby position C Branching position

Claims (6)

In a medium dispensing device that injects a medium stored in a medium container equipped with a heat retaining and stirring device into a dispensing container,
The medium in the medium container, a medium delivery channel serving as a medium channel leading to a nozzle to be injected into the dispensing container,
One end is branched and connected in the middle of the culture medium delivery flow path, and the other end is connected to the culture medium container, and a culture medium return flow path serving as a culture medium flow path for returning the culture medium to the culture medium container,
A dispensing pump that is disposed upstream of the branch position of the culture medium sending flow path with the medium return flow path and sends out the medium in the medium container to the medium sending flow path,
In the middle of the medium delivery flow path, disposed on the downstream side from the branch position, a first opening and closing valve for opening and closing the flow path of the medium delivery flow path,
In the middle of the medium return channel, disposed on the downstream side of the branch position, a second on-off valve for opening and closing the medium return channel,
In a section downstream of the branch position of the medium delivery channel, an auxiliary heating unit that heats and adjusts the medium in the medium delivery channel to a desired temperature,
A control device for controlling the operation of the dispensing pump, the auxiliary heating means, the first and second on-off valves,
A medium dispensing device comprising: The medium dispensing device according to claim 1, wherein the auxiliary heating means is an infrared lamp. The medium dispensing device according to claim 1 or 2, further comprising a filter provided at an upper portion of the medium container to supply aseptic air into the medium container. A medium dispensing method for injecting a predetermined amount of medium into a dispensing container using the medium dispensing device according to any one of claims 1 to 3,
The culture medium sending flow path and the culture medium return flow path from the culture medium container to the branch position closed the first opening / closing valve and opened the second opening / closing valve at the time of dispensing standby operation, so that the temperature inside the culture medium container was maintained. While the culture medium is circulated by the dispensing pump to maintain the culture medium at an appropriate temperature, the culture medium delivery channel in the section from the branch position to the nozzle is configured to maintain the culture medium at an appropriate temperature by heating by the auxiliary heating means. Characteristic medium dispensing method. A dispensing container using the medium dispensing device according to any one of claims 1 to 3, further comprising a nozzle capable of moving back and forth between a predetermined dispensing position and a standby position deviating from the dispensing position. A medium dispensing method of injecting a predetermined amount of medium into
During the dispensing standby operation, the nozzle is kept in the retracted state at the standby position, and the second on-off valve is closed and the first on-off valve is opened immediately before the start of the dispensing operation. A medium dispensing method, wherein a pump is operated to discharge a medium at the nozzle tip whose quality has become inappropriate at a standby position. A medium dispensing method for injecting a predetermined amount of medium into a dispensing container using the medium dispensing device according to claim 3,
The medium delivery flow path and the medium return flow path from the medium container to the branch position, the first open / close valve and the second open / close valve are opened during the dispensing standby operation to open the medium in the medium container. A medium dispensing method, wherein the medium is maintained in a sterile state by circulating the medium by a dispensing pump, and when the medium is dispensed, sterile air is supplied into the medium container through the filter.

Images