JPH05288653A - Automatic sampling apparatus - Google Patents

Abstract

PURPOSE:To improve the working environment by automating the sampling work, which is performed for every specified time interval during the culturing operation for long time. CONSTITUTION:The pressure in culture tank 1 rises up by the blowing of air through an air blowing nozzle 3 when an exhaust valve 6 is closed. Under this state, culture liquid 2 is sent into a sampling bottle 14a through a sampling needle 8, a pushing tube 9 and a branching tube 13a. After the specified time, the culture liquid 2 is sent into a next sampling bottle 14b by repeating the same operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The automatic sampling device according to the present invention is attached to a culturing device for culturing various microorganisms or plant cells and is used for extracting (sampling) a culture solution in a culture tank during the culturing work. To use.

[0002]

2. Description of the Related Art In recent years, it has been widely practiced to culture various microorganisms and plant cells by using a culturing apparatus called a jar fermenter, a bioreactor or the like. When carrying out the culturing work, the above-mentioned microorganisms and plant cells are put together with the culture solution in the culture tank constituting the culture apparatus, and the temperature, oxygen concentration, nutrient concentration, PH value, etc. of the culture solution are maintained at desired values. Meanwhile, the culture solution is stirred.

Whether or not the culturing work is proceeding as planned during the culturing work is detected by a sensor placed in the culturing tank, and the culture solution in this culturing tank is checked through a sampling valve provided at the bottom of the culturing tank. It is judged by taking out a part and analyzing the taken out culture solution. In order to perform a so-called sampling operation in which a part of the culture solution is taken out in this manner, a sampling valve has been conventionally provided at the bottom of the culture tank so that the culture solution in the culture tank can be appropriately taken out.

When performing a sampling operation, an operator opens and closes the sampling valve and transfers a part of the culture solution in the culture tank into a container such as a beaker. The sampling work is performed a plurality of times at predetermined time intervals during the culture work.

[0005]

The automatic sampling apparatus of the present invention reduces the burden on the operator by automating the sampling operation as described above. That is, since the culturing work often lasts for a long time, and therefore the sampling work is often performed in the middle of the night, it is desirable from the standpoint of improving the working environment that the above-mentioned sampling work can be performed automatically. It is rare.

The automatic sampling device of the present invention was invented in view of the above circumstances.

[0007]

Among the automatic sampling devices of the present invention, the automatic sampling device according to claim 1 is a hermetically sealed container storing a liquid to be sampled a plurality of times at different times, and the hermetically sealed container. An exhaust tube for discharging the gas in the container, an exhaust valve provided in the middle of the exhaust tube, and the inside of the closed container, one end of which is communicated with the liquid, the other end to the clean gas supply section. A push-out tube that communicates with each other, a first opening / closing valve provided at a portion near the other end of the push-out tube, and a branch that is arranged in parallel with each other by branching respective base end portions from an intermediate portion of the push-out tube. Tubes, a plurality of sampling bottles, one connected to the tip of each branch tube, and provided in the middle of each branch tube, independently of each other. Closed freely, a plurality of second switching valve, and the air supply device for supplying a gas into the closed vessel,
A controller for controlling opening / closing of the exhaust valve and opening / closing of the first and second opening / closing valves.

The controller closes the first on-off valve, opens any one of the second on-off valves, and closes the exhaust valve for a predetermined time, and then any one of the two open-close valves. It has a function of repeatedly performing the operation of closing the second opening / closing valve and opening the exhaust valve and the first opening / closing valve by changing the opening / closing second opening / closing valve each time.

The automatic sampling device according to a second aspect is the automatic sampling device according to the first aspect, wherein each branch tube is made of a material having a heat-welding property, and In the middle part, a welding device is provided which can weld and close this branch tube.

Further, the automatic sampling device according to a third aspect of the present invention is a container for storing a liquid to be sampled a plurality of times in time, and a container which is inserted into the container and whose lower end is communicated with the liquid. Suction tube, a third opening / closing valve provided in the middle of this suction tube, a closed chamber provided at the upper end of this suction tube, and an extrusion tube having one end opened at the bottom of this closed chamber. A sampling tube that is made of a material having heat-welding properties, connects the base end to the other end of the extruded tube and closes the tip, and provides a slack portion near the base end; A fourth on-off valve provided in the middle of one side of the push-out tube, a feeding device that feeds the sampling tube toward the tip side thereof, and a sampling chute. Provided near the tip end portion of the over blanking,
A welding device capable of welding and closing the sampling tube, and an exhaust device for discharging gas in the closed chamber,
An air supply device for sending gas into the closed chamber, and a controller for controlling the third and fourth on-off valves, the feeding device, the exhaust device, and the air supply device are provided.

The controller closes the third opening / closing valve, opens the fourth opening / closing valve, and makes the exhaust device function with the function of the air supply device stopped. A second step of opening the third and fourth on-off valves in a state where the functions of the air supply device and the exhaust device are stopped, and a third step of welding the vicinity of the tip end portion of the sampling tube by the welding device. And close the fourth on-off valve above,
The third opening / closing valve is opened, and in a state where the function of the exhaust device is stopped, a fourth step of operating the air supply device, the third opening / closing valve is closed, and the fourth opening / closing valve is opened, A state in which the function of the air supply device is stopped, a fifth step of operating the exhaust device, the fourth opening / closing valve is closed, the third opening / closing valve is opened, and the function of the exhaust device is stopped. so,
It has a function of repeatedly performing the sixth step of operating the air supply device, and of feeding the sampling tube by a predetermined length by the feeding device after the third step.

Further, in the case of the automatic sampling device described in claim 4, instead of omitting the feeding device and the slack portion from the automatic sampling device described in claim 3, the welding device is attached to the sampling tube. It is free to move along. Furthermore, in the case of the automatic sampling device described in claim 5, the order of the third step and the fourth step is interchanged.

[0013]

The operation of the automatic sampling device according to the first aspect of the automatic sampling device of the present invention configured as described above is as follows.

During standby, that is, when sampling is not performed, both the first and second on-off valves are closed.

When the first sampling operation is performed, the exhaust valve is closed for a predetermined time while the first opening / closing valve is closed and any one of the second opening / closing valves is opened.
As a result, the pressure in the closed container rises, and the liquid in the closed container is pushed out to the extrusion tube.
It is sent into any one of the sampling bottles through a branch tube provided with a second opening / closing valve.

After continuing to open the second on-off valve for a time sufficient to send the required amount of liquid into the sampling bottle, any one of the second on-off valves is closed, and
The exhaust valve and the first opening / closing valve are opened. As a result, further liquid feeding into the sampling bottle is stopped.

When performing the second and subsequent sampling operations, the second on-off valve that is opened and closed is changed each time, and the above-described operation is repeated to connect to the end of each branch tube. Collect the liquid in the closed container in the sampling bottle at different sampling times. The second on-off valve in the middle of the branch tube leading to the sampling bottle from which the liquid has already been collected is kept closed thereafter.

However, in the case of the automatic sampling device described in claim 2, the liquid is sampled in a sampling bottle,
With the second on-off valve closed, the middle part of the branch tube is welded and closed. Therefore, thereafter, the open / closed state of the second on-off valve does not cause any particular problem.

Further, when performing the sampling work by the automatic sampling device according to the third aspect, first, as a first stroke, the third opening / closing valve is closed, the fourth opening / closing valve is opened, and the air supply is performed. The exhaust device is operated with the function of the device stopped. As a result, a negative pressure is created in the closed chamber and the sampling tube.

Then, in a second step, the third and fourth on-off valves are opened while the functions of the air supply device and the exhaust device are stopped. As a result, the liquid in the container is sucked into the closed chamber and the sampling tube.

Then, in a third step, the position near the tip of the sampling tube is welded by a welding device. As a result, a part of the liquid sucked into the sampling tube seals the part existing at the tip.

Then, in a fourth step, the fourth air supply valve is closed, the third air supply valve is opened, and the air supply device is operated with the function of the exhaust device stopped. As a result, the liquid remaining in the closed chamber is returned to the container. The order of the fourth step and the third step may be reversed.

Then, in a fifth step, the third opening / closing valve is closed, the fourth opening / closing valve is opened, and the exhaust device is made to function with the function of the air supply device being stopped. As a result, the liquid existing in the portion closer to the closed chamber than the welding position in the sampling tube is returned to the closed chamber.

Further, in the sixth stroke, as in the case of the fourth stroke, the fourth opening / closing valve is closed, the third opening / closing valve is opened, and the function of the exhaust device is stopped, while the supply is performed. The air device is operated to return the liquid returned from the sampling tube to the closed chamber to the container. or,
The feeder prepares for the next sampling operation by feeding the sampling tube by a predetermined length after the third step. Hereinafter, the above-mentioned first to sixth steps are repeated at predetermined time intervals.

[0025]

FIG. 1 shows a first embodiment of the present invention corresponding to claim 2. In the culture tank 1 which is a closed container,
The culture solution 2, which is a liquid to be sampled a plurality of times at different times, is stored. The bottom of the culture tank 1 is provided with an air jet nozzle 3 which constitutes an air supply device, so that clean air can be freely jetted into the culture solution 2.

One end of an exhaust tube 5 for exhausting air from the culture tank 1 is connected to one corner of the lid plate 4 that closes the upper end opening of the culture tank 1, and in the middle of the exhaust tube 5, An exhaust valve 6 that can open and close the air flow path is provided.

A rubber lid 7 is provided at the other corner of the lid plate 4, and the lower end of a hollow tubular collection needle 8 that penetrates the rubber lid 7 in an airtight manner is opened in the culture solution 2. ing. Then, one end of an extruding tube 9 made of a soft material such as vinyl is connected to a portion of the upper end of the sampling needle 8 located above the cover plate 4. One end of the push-out tube 9 is communicated with the culture solution 2 through the sampling needle 8, and the other end is communicated with the atmosphere through the filter 10,
Alternatively, it is communicated with the discharge port of a compressor (not shown).

The pinch valve 11, which pinches the extruded tube 9 at both ends of the extruded tube 9, closes the channel, and opens the channel by releasing the pinching force. 12 are provided. Of these, the pinch valve 12 provided on the portion near the other end (right end in FIG. 1) of the push-out tube 9 functions as a first opening / closing valve. Further, the push-out tube 9 is arranged at a position higher than the liquid surface of the culture medium 2, and more preferably from one end (the left end in FIG. 1) to the other end (from left to right in FIG. 1). ), It is inclined so that it gradually becomes higher.

A plurality of branch tubes 13a, 13b to 13n (n is an arbitrary integer of 3 or more) are provided at an intermediate portion of the push-out tube 9 and between the pair of pinch valves 11 and 12. The base end portion (upper end portion in FIG. 1) is branched and the branch tubes 13a and 13b to 13n are arranged in parallel with each other. Similar to the extruded tube 9, the lower ends of the branch tubes 13a, 13b to 13n made of a soft and heat-welding material such as vinyl are
One sampling bottle 14a and one sampling bottle 14n are connected to each. Each sampling bottle 14
Exhaust ports 16 and 16 provided with filters 15 and 15 are provided on the upper portions of a and 14b to 14n.

Further, each of the branch tubes 13a, 13b-
Pinch valves 17a, 17b to 17n that can be opened and closed independently of each other are provided in the middle of 13n. Each of these pinch valves 17a and 17b to 17n corresponds to a second on-off valve.

Further, each of the branch tubes 13a and 13b described above
Each of the pinch valves 17a, 17a,
b-17n and each sampling bottle 14a, 14b-1
4n, the branch tubes 13a, 13
High frequency welding device 1 for welding the intermediate portion of b to 13n
8a and 18b-18n are provided. Each of the high frequency welding devices 18a, 18b to 18n operates independently of each other, and at the time of operation, the branch tubes 13a, 1b between the pair of electrodes.
While strongly sandwiching the intermediate portion of 3b to 13n, a high-frequency current is passed between the electrodes, and the branch tubes 13a and 13b.
The middle part of ~ 13n is welded and closed.

The opening and closing of the exhaust valve 6 and the opening and closing of the pinch valves 11, 12, 17a, 17b to 17n, which constitute the automatic sampling device of the present invention in combination as described above, are controlled by a controller (not shown). It

This controller opens the exhaust valve 6 in the standby state, that is, when sampling is not performed, and the pinch valves 11, 12, 17a, 17b to 17 are opened.
All n are closed. As a result, the clean air sent from the fumarolic nozzle 3 into the culture tank 1 is discharged to the outside via the exhaust tube 5. Therefore, the pressure increase in the culture tank 1 is suppressed.

When the first sampling operation is performed, the exhaust valve 6 is closed (including the case of narrowing the flow path. The exhaust valve is the same throughout the present specification), and one end of the extruding tube 9 is connected. The pinch valve 11 provided is opened and the pinch valve 12 near the other end of the push-out tube 9, which is the first opening / closing valve, is closed. Then, of the plurality of pinch valves 17a, 17b to 17n, only the pinch valve 17a provided in the middle of the branch tube 13a leading to the sampling bottle 14a at one end is opened.

As a result, the pressure in the culture tank 1 rises, the culture solution 2 in the culture tank 1 is extruded into the extruding tube 9 via the sampling needle 8, and from the extruding tube 9 the branch tube 13a. Through the branch tube 13a into the sampling bottle 14a connected to the tip (the lower end in FIG. 1) of the branch tube 13a.

If the pinch valve 17a is kept open and the exhaust valve 6 is kept closed for a time period sufficient for feeding the culture solution 2 in an amount required for the test into the sampling bottle 14a, then the pinch valve 17a is then closed. Is closed, and the pinch valve 12 near the other end of the exhaust valve 6 and the push-out tube 9 is opened. Also, the branch tube 13
The high frequency welding device 18a provided in the middle part of a is operated,
The middle portion of the branch tube 13a is welded and closed.

As a result, the sampling bottle 14a
Further feeding of the culture solution 2 into the inside is stopped.
In addition, the culture solution 2 remaining in the extrusion tube 9
Flows down this extruded tube 9 based on gravity,
It is returned to the inside of the culture tank 1. In addition, when it is necessary to completely return the culture solution 2 in the extruding tube 9 to the culture tank 1, and when the culture solution 2 cannot be completely returned by gravity alone, or when the extruding tube 9 is in the culture solution 2 in the culture tank 1, When it is provided at a position lower than the liquid surface of,
It is also possible to send air from the other end opening side of the extruding tube 9 by an air supply compressor (not shown). Since the filter 10 is provided at the other end of the extruded tube 9, bacteria and the like are not fed into the culture tank 1. The pinch valve 11 is closed after the culture solution in the extrusion tube 9 is completely replaced with clean air.

When the sampling work performed as described above is completed, the exhaust valve 6 is opened, and the pinch valves 11, 12, 17a, 17b to 17n are all closed.
Keep the automatic sampling device in a standby state.

When the second sampling operation is performed after a predetermined time has elapsed, the above-described operation is performed by opening and closing the pinch valve 17b instead of the pinch valve 17a, and the culture solution is placed in the sampling bottle 14b. Send in 2. Hereinafter, by repeating the same work at predetermined time intervals, the sampling bottles 14a, 14b ...
The culture solution 2 in the culture tank 1 is collected in 14n.

Next, FIG. 2 shows a second embodiment of the present invention corresponding to claim 3. A rubber lid 7 is provided at the center of the lid plate 4 attached to the upper opening of the culture tank 1 that stores the culture solution 2, and the lower end of the hollow tubular collection needle 8 that hermetically penetrates the rubber lid 7 is provided. Are opened in the culture medium 2. By connecting the lower end of the suction tube 19 to the upper end of the sampling needle 8, the suction tube 19 is communicated with the culture solution 2.

A pinch valve 20, which is a third opening / closing valve, is provided in the middle of the suction tube 19 made of a soft material such as vinyl so that the flow passage in the suction tube 19 can be opened and closed. A closed chamber 21 is provided at the upper end of the suction tube 19, and the lower end of the push-out tube 22 is opened at the bottom of the closed chamber 21. A pinch valve 23, which is a fourth on-off valve, is provided in the middle of the extruding tube 22 made of a soft material such as vinyl so that the passage in the extruding tube 22 can be opened and closed.

At the upper end of the extruded tube 22,
A base end portion of the sampling tube 24, which is made of a material having a heat-welding property and whose front end portion (right end portion in FIG. 2) is closed, is connected. The portion of the sampling tube 24 near the base end is wound into a coil to form a slack portion 25,
Even when the tip end portion of the sampling tube 24 is fed out by the feed rollers 26, 26 described below, the base end portion of the push-out tube 22 is prevented from being pulled.

At the portion near the tip of the sampling tube 24, a feeding device including a pair of feed rollers 26 and 26 rotating in opposite directions is provided in order to feed the sampling tube 24 toward the tip side thereof. .. A high-frequency welding device 27 is provided at the tip of the sampling tube 24, which is closer to the tip than the feeding device, so that the sampling tube 24 can be welded and closed.

An upper end of the closed chamber 21 is provided with an end of a supply / exhaust tube 28 made of a soft material.
A filter 29 is provided in the middle of the air supply / exhaust tube 28.
And the pinch valve 30 are provided in series with each other.

Further, the other end of the air supply / exhaust tube 28 is
Each is branched into an air supply tube 31 and an exhaust tube 32, which are made of a soft material. Then, the air supply tube 31 therein is connected to the discharge port of the vacuum pump to form an air supply device for sending the compressed air into the closed chamber 21, and the exhaust tube 32 is connected to the intake port of the vacuum pump. And an exhaust device for discharging the air in the closed chamber 21. Pinch valves 33 and 34 are provided in the middle of the air supply tube 31 and the exhaust tube 32, respectively.

Each of the pinch valves 20, 23, which constitute the automatic sampling device of the present invention by combining as described above,
The opening / closing of 30, 33, 34 is controlled by a controller (not shown). When the controller is on standby, that is, when sampling work is not performed, all the pinch valves 2
0, 23, 30, 33, 34 are closed.

When the sampling operation is carried out by taking the culture solution 2 in the culture tank 1 into the sampling tube 24, first, as the first step, the pinch valves 20 and 33 are kept closed and the pinch valves 23 and 30 are kept. , 34 are opened and a vacuum pump (not shown) is operated. As a result, the pressure inside the closed chamber 21 and the sampling tube 24 becomes negative.

Then, as a second step, the pinch valves 30 are closed (the pinch valves 33 and 34 may be opened or closed) and the pinch valves 20 and 23 are opened. As a result,
The culture solution 2 in the culture tank 1 is a collection needle 8 and a suction tube 19.
Through the suction chamber 21 and the sampling tube 24.

Next, in the third step, the vicinity of the tip of the sampling tube 24 is clamped by a pair of electrodes constituting the high frequency welding device 27, and a high frequency current is applied between the pair of electrodes. The position near the tip of the sampling tube 24 is welded. As a result, a part of the culture solution 2 sucked into the sampling tube 24 seals the part existing at the tip.

Next, as a fourth step, with the pinch valves 23 and 34 closed and the pinch valves 20 and 30 open, the pinch valve 33 is opened and compressed air is sent into the closed chamber 21. As a result, the culture solution 2 remaining in the closed chamber 21 is pushed back into the culture tank 1 through the suction tube 19 and the sampling needle 8.

Then, as a fifth step, with the pinch valves 20 and 33 closed and the pinch valves 23 and 30 opened, the pinch valve 34 is opened to make the inside of the closed chamber 21 negative pressure. As a result, in the sampling tube 24, the culture solution 2 existing in a portion closer to the closed chamber 21 than the welding position of the high frequency welding device 27.
Are returned to the closed chamber 21.

Further, in the sixth step, as in the case of the fourth step, the pinch valves 23 and 34 are closed and the pinch valves 20 and 30 are opened, and the pinch valve 33 is opened to open the closed chamber. Compressed air is fed into 21. As a result, the culture solution 2 returned from the sampling tube 24 into the closed chamber 21 is pushed back into the culture tank 1 through the suction tube 19 and the sampling needle 8.

Further, the feed roller 26 constituting the feeding device,
26 is rotated for a predetermined time after the third stroke to feed the sampling tube 24 by a predetermined length to prepare for the next sampling operation. Hereinafter, the same operation is repeated at predetermined time intervals to collect the culture solution 2 in the culture tank 1 in the sampling tube 24. The culture liquids 2 sealed in the sampling tube 24 at different times are separated from each other by the partition formed by the welding work and do not mix with each other.

[0054]

The automatic sampling device of the present invention is constructed and operates as described above. However, when performing a culturing operation for a long time and the like, and the sampling operation is performed in the middle of the night, the sampling operation is unattended. The work environment can be improved because it can be done automatically. Further, it is possible to completely prevent the culture solution from leaking due to the sampling work.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

 1 Culture Tank 2 Culture Liquid 3 Fume Nozzle 4 Lid Plate 5 Exhaust Tube 6 Exhaust Valve 7 Rubber Lid 8 Collection Needle 9 Extrusion Tube 10 Filter 11, 12 Pinch Valve 13a, 13b, 13n Branch Tube 14a, 14b, 14n Sampling Bottle 15 Filter 16 Exhaust ports 17a, 17b, 17n Pinch valve 18a, 18b, 18n High frequency welding device 19 Suction tube 20 Pinch valve 21 Closed chamber 22 Extrusion tube 23 Pinch valve 24 Sampling tube 25 Loose portion 26 Feed roller 27 High frequency welding device 28 Supply and exhaust tube 29 Filter 30 Pinch valve 31 Air supply tube 32 Exhaust tube 33, 34 Pinch valve

Claims (5)

[Claims] 1. An airtight container storing a liquid to be sampled a plurality of times over time, an exhaust tube for exhausting gas in the airtight container, an exhaust valve provided in the middle of the exhaust tube, A push-out tube inserted into a closed container, one end of which is in communication with the liquid and the other end of which is in communication with a clean gas supply unit, and a first on-off valve provided in a portion near the other end of the push-out tube, respectively. A branch tube in which each base end portion is branched from the middle portion of the extruded tube and arranged in parallel with each other, and a plurality of sampling bottles each connected to the tip end portion of each branch tube, A plurality of second on-off valves provided in the middle of each branch tube and capable of opening and closing independently of each other, an air supply device for supplying gas into the closed container, and opening of the exhaust valve. A controller for controlling closing and opening / closing of the first and second opening / closing valves, the controller closing the first opening / closing valve and opening any one of the second opening / closing valves. After closing the exhaust valve for a predetermined time, the second opening / closing valve for opening / closing the operation of closing any one of the second opening / closing valves to open the exhaust valve and the first opening / closing valve An automatic sampling device that has the function of changing each time and repeating. 2. The automatic sampling apparatus according to claim 1, wherein each branch tube is made of a material having a heat-welding property, and a welding device capable of welding and closing the branch tube is provided at an intermediate portion of each branch tube. .. 3. A container in which a liquid to be sampled a plurality of times with a time shift is stored, a suction tube inserted into the container, the lower end of which is communicated with the liquid, and a suction tube in the middle of the suction tube. A third on-off valve provided, and a closed chamber provided at the upper end of this suction tube,
An extrusion tube having one end opened at the bottom of this closed chamber, and a material having heat-welding properties.The proximal end is connected to the other end of the extrusion tube and the distal end is closed. A sampling tube provided with a slack portion, a fourth opening / closing valve provided in the middle of one of the sampling tube and the pushing tube, a feeding device for feeding the sampling tube toward its tip side, and a tip of the sampling tube A welding device which is provided at a side portion and which can weld and close the sampling tube, an exhaust device for discharging gas in the closed chamber, an air supply device for feeding clean gas into the closed chamber, the third and third And a controller for controlling the four on-off valves, the feeding device, the exhaust device, and the air supply device, the controller closing the third on-off valve, The first opening and closing of the fourth opening and closing valve, the first step of operating the exhaust device in the state of stopping the function of the air supply device, and the third in the state of stopping the functions of the air supply device and the exhaust device, A second stroke of opening the fourth on-off valve, a third stroke of welding the position near the tip of the sampling tube by the welding device, a closing of the fourth on-off valve and an opening of the third on-off valve. A fourth stroke of operating the air supply device with the function of the exhaust device stopped, and closing the third opening / closing valve and opening the fourth opening / closing valve to stop the function of the air supply device. In the state, the fifth step of operating the exhaust device, the fourth opening / closing valve is closed, the third opening / closing valve is opened, and the function of the air supply device is operated with the function of the exhaust device stopped. Repeat the 6th step and repeat the above 3rd step After an automatic sampling device having a function of send the sampling tube by a predetermined length by the feeding device. 4. Instead of omitting the feeding device and the slack part,
The automatic sampling device according to claim 3, wherein the welding device is movable along the sampling tube. 5. The automatic sampling device according to claim 3, wherein the order of the third stroke and the fourth stroke is exchanged.