DE102007030790A1 - Flowable substance e.g. low viscous substance, dosing device for combinatory chemistry, has piston acting on container such that space of container is reduced by pressing container, and dosing valve arranged in base of container - Google Patents

Abstract

The device has a container (1) enclosing a space that contains flowable substance. The space is compressible by a piston such that the substance flows out through an outlet (7) by the compression of the space. The container has a flexible wall (3), and the piston acts on the container such that the space is reduced by pressing the container. A dosing valve (9) is arranged in a base (5) of the container. A filling opening is positioned at an upper side of the container. An independent claim is also included for a method for operating a dosing device.

Description

State of the art

The The invention relates to a device for metering flowable substances according to the generic term of claim 1. Furthermore, the invention relates to a method for operating a device for dosing.

method and dosage devices are used, for example in combinatorial chemistry. Here are flowable substances generally dosed gravimetrically or volumetrically. Usually this is a cylindrical container The latter comprises a metering piston which is pressed into the container can be to one in the container to compress the space contained in it, thereby containing the space contained in the space flowable substance to squeeze out of an outlet opening.

disadvantage the dosing systems known from the prior art is that for flowable substances with big ones viscosity due to insufficient pressure stability of the container during metered addition of the substance the piston rod can bend. Usually, the containers and Pistons for the Metering, precision injection molded parts. this leads to too high production costs of the container and pistons. Because the piston in the container is moved, an integrated seal for the piston is required, so that no substance can flow past the piston as leakage. Usually the piston will after filling the substance in the container used. This makes an additional handling device required for insertion of the piston. Since the container with It is also not possible to close the piston, for example a barcode for to attach the lot number to the top of the container. This one can only on the container wall, d. H. on the side of the cylinder surface be attached. When the containers are stored in grid trays in which only the top, d. H. the side into which the piston is inserted, must be visible to identify each individual container taken from the lattice tray become.

One Another disadvantage of the known from the prior art container it that after putting on the piston a relatively large storage volume needed is because the piston volume is also taken into account.

Besides that is for dosing from the containers known from the prior art additional Tilting degree necessary to fill the filled and closed with the piston Reaction vessel of the Filling in to be able to turn the dosing position.

Finally is it is a further disadvantage of those known from the prior art Systems that allow it when dosing low viscous liquids too An uncontrolled dripping may occur as the outlet opening in the Generally not lockable is.

Disclosure of the invention

Advantages of the invention

A formed according to the invention Device for metering flowable substances comprises a Container, which encloses a room, in which the flowable substance is included. The space is compressible by means of a piston. By compressing the space, the flowable substance flows out through an outlet opening. The container has a flexible wall, so that a piston on the container can act to reduce the space by pressing the container becomes.

Thereby, that the space is compressed by pressing the container needs the piston should not be part of the container. The required storage volume for individual reaction vessel is thus smaller than in the known from the prior art container with attached piston.

In a preferred embodiment is the wall of the container wavy educated. Advantage of wavy Embodiment is that thereby the wall flexible elastic is. this makes possible an elastic springback of the container. hereby creates a suck-back effect, which leads that after the dosing process no liquid dripping more.

Wavy in the Meaning of the present invention means in addition to a classic Waveform, for example, also zigzag.

Around one possible full Emptying the container it is preferred that the corrugated wall has film hinges, so that the container is compressible to block.

In a preferred embodiment, a metering valve is received in the outlet opening of the container. The metering valve prevents the flowable substance contained in the container from dropping at the end of the metering process. Also prevented by the metering valve that unwanted substance can leak. The metering valve is preferably designed such that it opens when an overpressure arises in the container, as he for example by applying pressure to the Piston and the associated compression of the container is formed.

The fill of the container is generally about a filling opening. Preferably, the filling opening is on the top of the container arranged. Particularly preferably, the container is completely open at the top. About this opening can one or several substances are filled into the container. By moving the Container or through a stirrer The substances can be mixed together. The filling hole is preferably closed by a film. This is possible achieve a hermetic seal of the container interior. To closing the opening may also be a mixing of the substances in the container by shaking the container respectively. The mixing of the substances by shaking takes place preferably only after closing the filling opening, so that no substance from the container can expire. To prevent that contained in the container Substance, for example, with oxygen from air or other gaseous substances, which are also in the container react, it is possible before closing the filling opening across from the one in the container substance to be filled inert inert gas. Typical shielding gases are for For example, nitrogen, carbon dioxide or similar gases.

When Material for the container For example, elastic plastics or metals are suitable. Prefers as material for the container are polypropylene (PP), polyethylene (PE) or aluminum.

The Foil with which the container is closed, is preferably made of aluminum. Other suitable Materials for the foil for closing of the container are plastics, preferably polyvinyl chloride (PVC), polyethylene (PE) or polystyrene (PS), metallized plastic films or composite films.

The close of the container with the film is done for example by welding or Bonding. Furthermore, it is also possible to connect between container and foil by imprinting to achieve. Preferably, however, the film is sealed. This takes place for example by means of a polyethylene sealant layer Ultrasonic sealing and cutting methods known to the person skilled in the art. Alternatively, a thermal sealing device can also be used become.

Around the flowable substance from the container to dose the device according to the invention further preferably comprises a metering device comprising a chamber into which the container can be inserted is, as well as a piston, which acts on the container. To the substance to be able to dose first the container inserted into the dosing chamber. Subsequently, the piston on the container placed. With the piston, a pressure force is applied to the container, causing the container is compressed. The space in which the substance is contained is reduced in size. The pressure increases. This will open the outlet valve and the substance flows out. To the dosing process To finish, the piston is moved back to its original position. The container springs back to its original shape. This increases the Space in the container again, which reduces the pressure in the container. The exhaust valve closes. Upon further spring back arises in the space in the tank a negative pressure that results that no further substance can escape.

If the filling opening the top of the container is arranged, the piston preferably acts on the side of the container where the filling opening closed by the film is positioned. Around a damage To avoid the film, the piston acts preferably on the wall of the container.

in the Piston is in a particularly preferred embodiment, a displacement sensor received, which receives the distance between the film and the piston. With increasing pressure in the container buckles the foil outwards. This reduces the distance between the piston and the film. From the distance between the film and the piston can be the pressure in the container determine. This will be done first a pressure difference between the internal pressure in the container and determined by the pressure in the chamber. Based on the pressure in the chamber let yourself determine the pressure in the container from the pressure difference. The determination the pressure is preferably carried out in an evaluation unit.

In order to obtain a pressure equalization with the internal pressure of the container, it is preferred if the chamber of the metering device is a pressure chamber which is pressurized bar. The chamber is pressurized, for example, when a predetermined setpoint for the differential pressure has been achieved. Once the predetermined set point has been reached, the pressure in the chamber is changed so that a pressure equalization with the internal pressure in the container is achieved. The pressure increase in the chamber takes place, for example, by supplying compressed air. For example, when the pressure in the chamber is higher than the ambient pressure, it is possible to vent air from the chamber to lower the pressure therein. In addition to the pressure increase in the chamber by supplying compressed air, it is also possible to increase the pressure in the chamber by supplying any other fluid medium. The medium can be liquid or gaseous. It is only necessary to ensure that the medium is opposite to the materials of Be container and the pressure chamber is inert. Furthermore, it is preferred if the fluid is also inert to the substance contained in the container, if a leak should occur.

The The amount of substance to be metered is preferably from a pressure curve for the internal pressure in the container certainly. This makes it possible to determine the amount of substance directly from the pressure measurements.

A additional Detection of the volume flow or the mass is not required.

Further Advantages of the device according to the invention are that possible is to apply a bar code to the film. If several containers in a lattice tray are included, this can also be done without Removing the containers the container information in a simple way. If several substances are contained in the container Is it possible, a mixing process by a superimposed one To support longitudinal oscillation of the flexible container.

Brief description of the drawings

embodiments The invention is illustrated in the drawings and in the following Description closer explained.

It demonstrate

1 A view of a trained container according to the invention,

2 a section through an inventively designed container which is inserted into a metering device,

3 a metering valve,

4 a storage arrangement for a plurality of containers,

5 a pressure control for a container according to the invention with metering device.

Embodiments of the invention

In 1 a view of a container according to the invention is shown.

An inventively designed container 1 includes a wall 3 enclosing a space in which one or more substances can be filled. In the embodiment illustrated here, the container comprises 1 continue a floor 5 with an outlet 7 , In the outlet 7 is a metering valve 9 absorbed, which prevents, for example, low-viscosity substances from the container 1 can expire.

According to the invention, the wall is 3 of the container 1 wavy shaped. According to the invention, wavy also means zigzag-shaped. Due to the wavy design of the wall, the container can be 1 compress in the axial direction. This will make the room into a container 1 reduced, whereby the pressure therein when the container is closed 1 increases. The flowable substance in the container 1 is contained, flows over the outlet 7 out.

Closing the container 1 takes place for example with a foil 11 , The foil 11 can be smooth or textured. To the slide 11 on the container 1 Being able to fix it closes to the wavy structure of the wall 3 a cylindrical edge area 13 at. The sealing of the foil 11 on the cylindrical edge area 13 takes place according to customary methods known to the person skilled in the art. So the sealing can be done for example by imprinting, gluing or similar processes. However, the sealing is preferably carried out as described above by an ultrasonic sealing and cutting method or by means of a thermal sealing device.

The container 1 is for example a plastic injection molded part. Suitable plastics are, for example, polyethylene or polypropylene. A particularly suitable plastic is polypropylene.

For example, when the device of the invention is used in combinatorial chemistry where only small amounts of substance are needed, the outlet port is as in FIG 1 represented with a dispensing needle 15 connected. The dispensing needle 15 In this case, its construction corresponds, for example, to an injection needle, as is known to the person skilled in the art.

To the contents of the container 1 after application of the film 11 In order to identify, it is preferable if the film 11 with a barcode 17 is provided. The barcode 17 can be read by machine, for example, by known methods. By assigning the barcode 17 to a particular substance or a given mixture, the contents of the container 1 identify.

To the container 1 In the dosing process to be able to empty as completely as possible, are the vertices 19 the wave structure of the wall 3 preferably film hinges. By film hinge is meant a weakening in the film so that the film can fold at this point. Through the film hinges can be wavy trained wall 3 down to block, ie a concern of the folds, without structural damage compress. This will make the space inside the wall 3 reduced to a minimum size.

In 2 is a section through an inventively designed container which is inserted into a metering device shown.

Due to the sectional view is in 2 the space 21 to recognize, in which the flowable substance is contained. To dose the flowable substance, the container 1 in a metering device 23 used. The dosing device 23 includes a chamber 25 in which the container 1 is used. In the ground 27 the chamber 25 is an opening 29 formed, through which the outlet 7 with the dispensing needle 15 to be led. The floor 5 of the container 1 lies on the ground 27 the chamber 25 on.

The dosing device 23 further includes a piston 31 that on the container 1 is put on. The piston 31 includes an annular portion 33 standing on the cylindrical edge area 13 of the container 1 acts. This will avoid the foil 11 gets damaged when the piston 31 the container 1 compresses.

In the piston 31 is a transducer 35 taken, with which a distance 37 between the piston 31 and the foil 11 is measured. The transducer 35 is connected to an electronic evaluation unit, for example. As a transducer 35 is suitable for any remaining, known to those skilled Wegaufnehmer, with the distance 37 can be measured. Usually, the transducer is 35 an absolute encoder.

When dosing, ie when the piston 31 in the direction of the ground 27 the chamber 25 is moved, the container becomes 1 compressed. At the same time also decreases the volume of the room 39 that the container 1 surrounds, from. This increases the pressure in the room 39 at. To achieve a pressure equalization is in the wall 41 the dosing device 23 a pressure compensation opening 43 educated. The pressure in the room 39 For example, as shown here with a commercial pressure sensor 45 be determined.

To avoid the container 1 and the foil 11 be damaged while the flowable substance is metered, a pressure equalization is preferably carried out during the dosing process. This is the pressure in the room 39 that the container 1 surrounds the pressure in the room 21 of the container 1 customized. The pressure in the tank 1 becomes indirect through the distance 37 between the slide 11 and the piston 31 certainly. When the pressure in the room 21 of the container 1 rises, the film bulges 11 outward. The distance 37 between the slide 11 and the piston 31 shrinks. The greater the pressure difference between the pressure within the container 1 and outside the container 1 is, the more the film bulges 11 and the smaller the distance 37 , For pressure equalization, the pressure in the room 39 that the container 1 surrounds, increases. For this purpose, for example, compressed air in the room 39 injected until a pressure equalization is achieved. In addition to compressed air, however, any other pressurized fluid is suitable. Via a pressure equalization channel 47 in the piston 31 will also be the pressure in the area between the film 11 and the piston 31 the pressure in the room 39 equalized. Hierdruch reduces the pressure difference between the internal pressure in the container 1 and the pressure in the room 39 and the space between the slide 11 and the piston 31 , The curvature of the film 11 Forms back and the distance 37 increases again.

So no pressurized fluid on the piston 31 can flow past, is the piston 31 preferably against the wall 41 sealed. The seal is made with a sealing element 49 , The sealing element 49 For example, an O-ring is in a groove 51 in the piston 31 is included. With the sealing element 49 will the gap 53 between the piston 31 and the wall 41 the dosing device 23 sealed.

So through the Öffnugen 29 no pressurized fluid can flow, forming the bottom 5 of the container 1 and the ground 27 the chamber 25 preferably a flat seat, which acts as a sealing seat. Furthermore, however, it is also possible that a sealing element is seen easily. This can either be between the ground 5 of the container 1 and the floor 27 the chamber 25 be included, or in the area of the opening 29 between the wall of the opening 29 and the outlet 7 of the container 1 , For example, the sealing element may also be an O-ring or if the sealing element is between the bottom 5 of the container 1 and the floor 27 the chamber 25 is used to be a flat gasket.

In 3 a metering valve is shown.

Through the dosing valve 9 which is in the ground 5 of the container 1 is added, it is avoided that low-viscosity substances can dribble. Furthermore, it also avoids the substance from the container 1 runs out, as long as this is not in the dosing device 23 is included and the piston 31 on the container 1 acts.

Through the dosing valve 9 becomes the outlet 7 opposite the room 21 of the container 1 locked. The metering valve 9 is for example like in 3 dargesellt a ball valve. This includes a valve ball 55 using a spring element 57 ge gene a valve seat 59 is pressed to the outlet 7 to close. The valve seat 59 is preferably consich formed. In addition to the valve ball shown here 55 However, any other, known to the expert closing element can be used as a closing element. Accordingly, then the valve seat 59 in its geometry to adapt to the closing element.

The spring element 57 is preferably a diaphragm spring. However, any other suitable and known to those skilled spring element can be used, with which the closing element in the valve seat 59 can be made.

In 4 a storage arrangement for a plurality of containers is shown.

Especially in applications of combinatorial chemistry, it is necessary to have large quantities of containers 1 to be provided, each filled with different substances or different mixtures of substances. The storage of the containers 1 takes place, for example, in commercial grid trays. Because of the containers 1 with the foil 11 are closed and not, as known from the prior art, with a piston, they require significantly less space during storage. To get the flowable substance out of the container 1 to dose, this is from the lattice tray 61 removed and into the metering device 23 positioned.

In 5 is shown a metering device with pressure control.

The movement of the piston 31 to get flowable substance from the container 1 To dose, for example, with a servo-linear drive 63 , A servo linear operation 63 allows precise movement of the piston 31 in terms of speed and position.

To flowable substance from the container 1 To dose, this is initially in the chamber 25 the dosing device 23 used. Subsequently, the piston 31 on the container 1 placed. With the transducer 35 becomes the distance 37 between the slide 11 with which the container 1 is closed and the piston 31 measured. From the distance 37 can the pressure in the container 1 determine. Especially when dosing viscous substances in the container 1 high back pressure can be compensated via an equal external pressure. If this does not happen, otherwise the pressure sensitive container could 1 or the foil 11 damaged or even destroyed. For pressure equalization is the room 39 for example via a compressed air connection 65 pressurized with compressed air. In the compressed air connection 65 is a proportional valve 67 added. As soon as the proportional valve 67 opened, compressed air can enter the room 39 flow. Via the pressure equalization channel 47 will ensure that even in the area between the slide 11 and the piston 31 the pressure according to the pressure in the room 39 is increased. The pressure difference between the pressure in the tank 1 and the pressure in the room 39 results from the curvature of the film 11 and thus from the distance 37 between the slide 11 and the piston 31 ,

At the beginning, ie before the beginning of the dosing but already with on the cylindrical edge region 13 seated annular section 33 becomes the distance 37 between pistons 31 and foil 11 certainly. The value becomes a fixed setpoint for the pressure control loop 69 in a store 71 deposited. By the pressure control with the pressure control circuit 69 This ensures that the viscosity of the substance and the speed of the piston 31 dependent pressure inside the container 1 by the external pressure in the room 39 is compensated.

To the pressure in the room 39 reduce is a second valve 73 intended. When the pressure in the room 39 is too high, the valve will 73 open. Compressed air can leave the room 39 flow out. This reduces the pressure in the room 39 from. However, in addition to compressed air, as already described above, any other fluid is suitable. It is only necessary to ensure that the fluid is opposite the material of the container 1 is inert.

With the pressure sensor 45 becomes the pressure in the room 39 measured. By the one with the pressure sensor 45 measured pressure and the pressure difference resulting from the distance 37 between foil 11 and pistons 31 results, the actual pressure in the container can be 1 determine.

The amount of substance to be dosed results, for example, from a pressure curve. To dose the exact amount of substance, the pressure curve becomes a second control loop 75 specified. With the pressure sensor 45 will be the actual pressure in the container 1 determined. From the pressure 45 and the pressure curve, the second loop 75 is given, the speed of the piston 31 determined. This becomes the servo linear drive 63 given, the piston 31 emotional. In this way, an exact dosage is possible on the pressure determination. To avoid that substance runs after the dosing process, the movement of the piston 31 controlled so that at the end of dosing the pressure in the container 1 corresponds to the ambient pressure. As for opening the metering valve 9 an overpressure is required, closes the metering valve 9 as soon as the ambient pressure is reached. It can no longer run after substance. A defined end of the dosing process is achieved.

Claims (14)

Device for dosing flowable substances, comprising a container ( 1 ), a room ( 21 ), in which the flowable substance is received, whereby the space ( 21 ) by means of a piston ( 31 ) is compressible and by compressing the space ( 21 ) the flowable substance through an outlet opening ( 7 ) flows out, characterized in that the container ( 1 ) a flexible wall ( 3 ) and the piston ( 31 ) on the container ( 1 ) acts that the room ( 21 ) by pressing the container ( 1 ) is reduced. Device according to claim 1, characterized in that the wall ( 3 ) of the container ( 1 ) is wave-shaped. Device according to claim 2, characterized in that the wavy wall ( 3 ) Has film hinges, so that the container ( 1 ) is compressible to block. Device according to one of claims 1 to 3, characterized in that in the outlet opening ( 7 ) a metering valve ( 9 ) is recorded. Device according to one of claims 1 to 4, characterized in that the container ( 1 ) has a filling opening through a film ( 11 ) is closable. Apparatus according to claim 5, characterized in that the filling opening at the top of the container ( 1 ) is positioned. Device according to one of claims 1 to 6, further comprising a metering device ( 23 ), which has a chamber ( 25 ) into which the container ( 1 ), and a piston ( 31 ) placed on the container ( 1 ) acts. Device according to claim 7, characterized in that the piston ( 31 ) on the side of the container ( 1 ) acting through the film ( 11 ) closed filling opening is positioned. Device according to claim 8, characterized in that in the piston ( 31 ) a transducer ( 35 ), which measures the distance between the film ( 11 ) and the piston ( 31 ). Device according to one of claims 7 to 9, characterized in that the chamber ( 25 ) of the dosing device ( 23 ) is a pressure chamber which can be acted upon by pressure, in order to equalize the pressure with the internal pressure of the container ( 1 ) to obtain. Method for operating a device according to one of claims 1 to 10, wherein a container filled with at least one substance ( 1 ) into the chamber ( 25 ) of the dosing device ( 23 ) is used and the piston ( 31 ) of the dosing device ( 23 ) on the container ( 1 ), the container ( 1 ) is compressed so that the room ( 21 ) in the container ( 1 ), in which the at least one substance is contained, is compressed, whereby the substance through the outlet opening ( 7 ) from the container ( 1 ) flows out. Method according to claim 11, characterized in that the displacement sensor ( 35 ) in the piston ( 31 ) the distance ( 37 ) between the piston ( 31 ) and the film ( 11 ), with which the container ( 1 ) is locked, measures and from the distance ( 37 ) in an evaluation unit, a pressure difference between the internal pressure in the container ( 1 ) and the pressure in the chamber ( 25 ) is determined. A method according to claim 12, characterized in that upon reaching a predetermined target value for the differential pressure of the pressure in the chamber ( 25 ) is changed so that a pressure equalization with the internal pressure in the container ( 1 ) is achieved. Method according to one of claims 11 to 13, characterized in that the amount of substance to be metered from a pressure curve for the internal pressure in the container ( 1 ) is determined.