WO2013167277A2 - Device for mixing liquids - Google Patents

Description

 Device for mixing liquids

The present application is concerned with a device for mixing liquids.

In devices where it depends on high accuracy of the mixing ratios, especially in the ultra trace range, it is necessary to clean the mixing vessels and the environment as well as possible and then keep clean. This is especially critical in the sub-ppt range (below parts per trillion), where the weight fraction of impurities must be less than 10 -12 ^" , which is particularly suitable for vessels that are not moving, but remain stationary and in which the mixture Stationary vessels allow the mixing device to be operated without personnel, for example, people coming close to the device may secrete sodium, which pollutes the mixture, and mixtures of highly aggressive liquids may endanger human health By contrast, movements of the vessels cause air turbulence which increases the risk of floating particles settling in the vessels, but in the case of stationary vessels, care must be taken to ensure that the vessels can be thoroughly cleaned.

The utility model DE 20 205 020 118 U1 shows a sampling device with a cleaning device for a dosing, which is cleaned by means of an ultrasonic actuator. However, it has been shown that such can cause chemical reactions in certain liquids. It is also possible that an ultrasound actuator causes unwanted movements in the fluid, which then splash around. In addition, it has been shown that the previous measures were not sufficient for the highest purity class. Devices for mixing liquids are shown in DE 102 60 141 A and DE 94 185 38 U1.

It is therefore an object of the invention to provide a device with which the mixing takes place reliably when required for highest purity. This object is solved by the subject matters of the independent claims, wherein advantageous developments of the invention are defined in the dependent claims. A device for mixing liquids is provided. The device comprises a vessel having an interior containing an opening at its lower end. The opening can be closed and opened by means of a closure. The apparatus also includes a drain pipe, the interior of which is connected to the opening, and a drain and a first valve for switchably connecting the drain to the drainage pipe. When mention is made here and in the following, this is not limited to inflexible pipe, it may also be a flexible hose.

The apparatus also includes a cleaning fluid reservoir for cleaning fluid and a second valve for switchably connecting the cleaning fluid reservoir to the drainage tube and transport means for transporting cleaning fluid from the cleaning fluid reservoir to the interior. The cleaning fluid reservoir can be designed, for example, as a container or as a supply system for ultrapure water, as is typically provided in clean rooms. The transport means may be a pump which ensures that the cleaning liquid in the first cleaning liquid reservoir is under pressure, so that the cleaning liquid can enter the interior. Alternatively, however, it is also possible, for example, to mount the cleaning liquid reservoir higher than the vessel, so that the cleaning liquid alone flows into the interior due to gravity when the second valve is open.

The device allows the cleaning liquid to be introduced into the vessel not only from above, but also to be passed through the drainage pipe. It may seem unusual at a first glance that cleaning fluid is passed through a drainpipe. However, it has been found that the conventional cleaning with cleaning fluid, for example with ultrapure water only from one side was not sufficient if the highest demands are made on purity. In the conventional cleaning, the flow of the cleaning liquid is only in one direction, so that flushing operations are similar. By contrast, as a result of the fact that cleaning fluid is also conducted through the outflow pipe, a flow is generated whose direction points out of the opening into the interior space. Depositions eg colloids on the walls and edges of the vessel can be better removed. In addition, deposits or concentrations of contaminants often occur near the opening in the space between the opening and the drainpipe. Particles from these deposits also diffuse into the interior, even if the main flow direction from the interior into the space and not vice versa. It is thus also advisable to provide the first liquid container beyond the drainpipe in order to thoroughly clean the gap.

In a preferred embodiment, the vessel contains an exterior space for catching liquid overflowing from the interior. Thus, the interior can be completely cleaned, that is to say to overflow, by cleaning liquid from the cleaning liquid reservoir. Thus, the side walls of the interior can be cleaned and protected up to their upper edge, because if you let the cleaning liquid slowly continue to run, that prevents falling from the top of the container particles pollute the liquid, as they are rinsed out the same.

In one embodiment, a drainage channel between the outer space and the drain is provided so that liquid, which, coming from inside, overflows, can also run off the same.

In a further embodiment, the device contains a further cleaning liquid reservoir and a liquid dispenser from the further cleaning liquid reservoir, the dispenser being provided above the interior such that liquid from the dispenser falls into the interior. With the aid of the further cleaning fluid device, it is possible to clean from above, so that the cleaning processes generate fluid movements that have different directions.

A dosing liquid dispenser in the apparatus serves to dispense liquid to be mixed into the interior of the vessel.

Preferably, an exhaust device and a pump is provided, wherein the exhaust device is connected to the drain pipe and the pump for generating a negative pressure is provided such that liquid particles from the interior into the Extractor be pulled. Thus, a drying process can be supported, so that the interior of the vessel is dried before a new dosing.

With a third valve between the exhaust device and the drain pipe, the drain pipe is separated from the interior of the exhaust device when liquid from the drain pipe is not intended to flow inadvertently into the exhaust device.

The application also relates to a liquid mixing apparatus comprising:

 a vessel with an interior for receiving liquids, a first dosing liquid discharge device for injecting liquid to be mixed into the interior, characterized in that the first dosing liquid discharge device has an end which has the shape of a tube and in that the orientation of the tube in an angle greater than 5 degrees to the vertical. The tail can also be referred to as a tip.

With this device, a movement of the discharged amounts of liquid is effected when draining the liquid having a velocity component in the horizontal direction. The movement is thus not only vertical. As a result, an impinging liquid droplet jet of about 0.3 mm diameter moves slightly laterally, whereby the liquid that is already in the interior of the vessel is also set in motion, so that the liquid is stirred in the interior.

The invention will be explained with reference to exemplary embodiments illustrated in the drawings.

FIG. 1 shows a device with several stationary vessels for mixing

 Liquids.

FIG. 2 shows one of the stationary vessels from FIG. 1 in cross section.

FIG. 3 shows a device with a stationary vessel.

FIG. 4 shows the device from FIG. 3 during filling of the vessel. FIG. 5 shows the device from FIG. 3, but during the emptying of the interior 3 of the vessel 2.

FIG. 6 shows the device from FIG. 3 during a rinsing process from above.

FIG. 7 shows the device from FIG. 3 during a rinsing process from below.

FIG. 8 shows a vessel interior with one end of a tube inserted in the tube

 Interior ends.

Figure 1 shows a device 1 for mixing liquids, wherein the device 1 is shown in a plan view. The device 1 contains three stationary vessels 2, in each of which liquids are mixed. In addition, the device 1 includes a pivot arm 8 to which a trunk 9 hangs. The swing arm 8 is movable so that it can pivot over the vessels 2 and, when it is above one of the vessels 2, it can stop to dip one end of the snout 9 into each of the vessels. Above the interiors 3 metering devices 6 are provided, from which liquid is discharged into the respective inner space 3. The proboscis 9 is connected to a tube 10 so that liquid sucked in through the proboscis 9 then flows through the interior of the tube 10 finally to the place of determination.

Each of the vessels 2 contains an inner space 3, an outer space 4, an intermediate wall 5 and an outer wall 7. The outer wall 7 and the intermediate wall 5 each extend concentrically such that the intermediate wall 5 separates the inner space 3 from the outer space 4 and the outer wall 7 separates the outer space 4 encloses. There are also other types in particular of the exterior space 4 possible. This can be rectangular, for example. However, a round outdoor space 4 is particularly easy to manufacture. The interior 3 serves to drain liquids into them. By adjusting the volumes of the different liquids, the mixing ratio is determined. Overall, all edges and corners are rounded, so there are no poorly flowed spaces that are particularly suitable for applying Depositionen invest.

As material for the components of the vessels 2 are mainly organic materials in use, which have very smooth surfaces and particularly chemically resistant, even if very aggressive materials such as hydrofluoric acid act on them are. One such material is the polytetrafluoroethylene (PTFE) sold under the brand name TFM, which has the modifier Perflourvinylesther (PPVE) as copolymer. This PTFE is soft and can be machined.

In the manufacture of the components of the device, the components should not be contaminated by tool residues. That is why tools made of solid carbide are preferably used. Solid means that not only the tips of the tools are made of tungsten carbide, but the majority of the tool is made of carbide. It has been found that in tools where only the tips are made of hard metal and these tips are soldered to the rest of the tool, the solder joints contaminate the components to be manufactured. For the same reason diamond tools are not so well suited, as they also have solder joints for fixing the diamonds.

FIG. 2 shows a cross section through one of the vessels 2. The intermediate wall 5 is shaped in such a way that the interior 3 tapers downwards. In other words, the boundary wall of the interior 3 extends from top to bottom not perpendicular, but at an angle of about 30 ⁰ to the vertical, such that the boundary wall tapers downwards. The diameter of the interior 3 thus decreases steadily from top to bottom. The outer space 4 is separated from the inner space 3 by the intermediate wall 5, however, the intermediate wall 5 is lower than the outer wall 7. When the inner space 3 is so full of liquid that it overflows, a part of the liquid flows into the outer space. 4

The interior 3 is open at the bottom, wherein the opening 15 formed thereby can be fired by a plug 14. The plug 14 serves as a closure and is movable up and down by an actuator 13. If the plug 14 is brought by means of the actuator 13 in its lowest position, the opening 10 is closed. On the other hand, when the plug 14 is in an upper position, the opening 15 is open, and then liquid flows through the opening 15 into a space 1 1 below the inner space 4. The space 11 opens down into a discharge hose 12, such that when the plug 14 is lifted, the liquid drains through the gap 11 into the drain hose 12. The outer space also contains at its bottom an opening 16, to which a drain channel 27 is connected, so that liquid, which passes from the top into the outer space 5, flows down into the drainage channel 27. For sealing the gap 11 from the environment in the region of the moving actuator 13, a seal 31 is provided. For seals, for example, the seal 13, in particular a perflour elastomer is suitable as it is marketed by the company Dupont under the brand name Kalrez®. This material seems to be already treated with strong acids, so that it does not react with hydrofluoric acid.

FIG. 3 shows a vessel 2 with further devices connected to the vessel 2. These devices are a first valve 23, a second valve 22, a third valve 21, an exhaust device 17, a pump 18, a reservoir 19 and a drain tank 20. FIG. 3 also shows a tube 24 under nitrogen nitrogen gas is passed into the vessel 2 and two further tubes 25 and 26, the function will be shown with reference to the other figures. The gas jet from the tube 24 is directed into the vessel 2 such that remaining liquid drops in the vessel 2 are pressed down to flow out of the interior 3 through the opening 10.

The third valve 21 is provided between the drain pipe 12 and the inlet E of the pump 18, the outlet A of the pump 18 is connected to the exhaust device 17. The second valve 22 is provided between the drain pipe 12 and the reservoir 19. The third valve 23 is connected between the drain pipe 12 and the drain tank. The first, second and third valves each have two switching states, either open or closed. In the state illustrated in FIG. 3, the first valve 22 is open and the second valve 22 and the third valve 23 are closed.

In the state shown in Figure 3, the plug is in an upper position, that is, the opening 10 is open. In addition, the pump 18 is turned on, which then generates at its input a negative pressure at its output A an overpressure. This causes a suction is formed, which sucks the gas from the drain pipe 12 and thus also the gas still inside 3 of the vessel 2, so that the liquid or liquid particles from the interior 3 through the gap 11, the drain pipe 12, the third Valve 21 and the pump 18 escapes into the exhaust device 17 or escape. With the aid of this device, the liquid is removed from the interior 3 of the vessel 3 and from the intermediate space 11, these components are thus dried, so that in future the vessel 2 can be reused for mixing and no errors are caused by residual amounts. FIG. 4 shows the device from FIG. 3 during filling of the vessel. In this figure, the tube 24 is not shown for clarity, although it is part of the device. The tube 25 is connected via a fourth valve 28 to a container, not shown here, in which there is liquid, which is used for mixing in the vessel. This may, for example, be a highly aggressive liquid such as hydrofluoric acid.

The pipe 26 is connected via a fifth valve 27 with a, not shown in this figure, container for ultrapure water. In this state, the fourth valve 28 is open and the remaining valves 21, 22, 23 and 27 are closed. Thus, liquid flows through the valve 28 into the interior 3 of the vessel 2. When more liquids enter the vessel

2 to be filled, this can be done via the pipe 25 or more, not shown here pipes. The tube may also be referred to as a dosing liquid dispenser.

Thus, the vessel 3 is filled with various liquids, the plug 4 remains in the lower position, so that the liquid does not drain. When all the liquids are filled and the mixing process is completed, the trunk 9 is lowered into the interior 3 of the vessel 2, after which liquid is sucked through the trunk 9 and is brought by this to its destination.

Figure 5 shows the device of Figure 3, but during the emptying of the interior

3 of the vessel 2. The valves 21, 22, 27 and 28 are closed while the valve 23 is open. In addition, the plug 14 is in an upper position. Liquid thus flows from the interior 3 through the intermediate space 11, through the drain pipe 12 and the valve 23 into the drain tank 20.

FIG. 6 shows the device from FIG. 3 during a first rinsing process. In this case, distilled water is discharged at a pressure of for example 1, 2 bar to 1, 4 bar from a further cleaning fluid reservoir not shown here via a throttle valve, not shown here and through the valve 27 and the tube 26 into the vessel 2. The distilled water then flows through the opening 10, the space 11, the drain pipe 12 and the valve 23 into the drain tank 20. Thus, residues of the mixture are removed from the interior. The vessel-side end of the tube 26 forms a dispenser 260 and is shaped so that the water also flows to where the liquids are dripping, as will be shown in one of the later figures. After this first flushing can still be sucked possibly in the space water by the pump 18.

FIG. 7 shows the device from FIG. 3 during a second rinsing process. In this distilled water from the cleaning liquid reservoir 19 through the valve 22, the drain pipe 12, the gap 11 and the opening 10 is pressed into the interior 3, in such a way that the water over the intermediate wall 5 over. Subsequently, the overflowed water runs into the channel 17 and then into the discharge tank 20. Thus impurities, for example deposited contaminants, collodors or particles from the gap 11 are better detached, since the water not only in one direction during the first rinse, but also flows in a second, opposite direction. In addition, all vessel inner surfaces and plug surfaces are wetted even when fully open plug 14. It is therefore important that the valve 23 is provided so that the water from the reservoir 19 can be pressed into the vessel and does not drain directly into the drain tank. In addition, when the valve 23 is closed, the relatively expensive cleaning solution can act for a long time when the first valve 14 is open. Repeated opening and closing of the plug can move the cleaning fluid, which aids cleaning and conditioning operations. This also improves the decontamination of the gap.

Figure 8 shows another embodiment of the shape of a vessel interior 3. The end 31 of the tube 25 is in the form of a tube, with the end 31 not pointing vertically downwards but slightly inwards. When liquid is discharged from the tip, the resulting liquid jet does not flow vertically downwards, but at an acute angle to the vertical s of, for example, 10 °. As a result, the liquid droplets or the liquid jet, of approximately 0.3 mm diameter, impinging on the surface of the liquid also have a velocity component in the horizontal direction. This agitates the liquid, which is aided by fluid swirl caused by the injected air.

The exemplary embodiments show possible embodiments. However, other embodiments are possible. For example, instead of the storage tank 19, a supply network for a laboratory or a factory may be provided. LIST OF REFERENCE NUMBERS

1 device

 2 vessel

 3 interior

 4 outdoor space

 5 partition

 6 dosing device

 7 outer wall

 8 swivel arm

 9 proboscis

 10 hose

 11 gap

 12 drainage pipe

 13 actor

 14 pegs

 15 opening

 16 opening

 17 exhaust air device

 18 pump

 19 cleaning fluid reservoir

20 drainage tank

 21 valve

 22 valve

 23 valve

 24 pipe

 25 pipe

 26 pipe

 27 drainage channel

 30 dosing liquid discharge device

31 seal

 190 cleaning fluid

 260 tail

 310 pipe

Claims

claims: A device (1) for mixing liquids, comprising:  a vessel (2) having an interior space (3) which has at its lower end an opening (15) which can be closed by means of a closure (14) and is to be opened, a drain pipe (12) whose interior is connected to the opening (15),  a drain (20) and a first valve (23) for switchably connecting the drain (20) to the drainage pipe (12),  a cleaning fluid reservoir (19) for cleaning fluid (190) and a second valve (22) for switchably connecting the cleaning fluid reservoir (19) to the drainage tube,  - A transport (p) for transporting cleaning liquid (190) from the cleaning liquid reservoir (19) to the interior (3). 2. Apparatus according to claim 1,  characterized in that the vessel has an exterior space (4) for catching liquid overflowing from the interior space (3). 3. Apparatus according to claim 2,  characterized in that a drainage channel (27) between the outer space (4) and the drain (20) is provided. 4. Device according to one of claims 1 to 3,  characterized in that a further cleaning liquid reservoir and a dispenser (260) for liquid from the further cleaning liquid reservoir is provided, wherein the dispenser (260) is provided above the interior (3) such that liquid from the dispenser (260) into the interior ( 3) falls. 5. Device according to one of claims 1 to 4,  characterized in that at least one dosing liquid dispenser (25) is provided for dispensing liquid to be mixed. 6. Device according to one of claims 1 to 5, characterized in that an exhaust device (17) and a pump (18) is provided, wherein the exhaust device (17) is connected to the drain pipe (12) and the pump (18) for generating a negative pressure is provided such that liquid particles from the Interior (3) are pulled into the exhaust device (17). 7. Apparatus according to claim 6,  characterized in that a third valve (21) between the exhaust device (17) and the drain pipe (12) is provided. 8. Device according to one of claims 1 to 6,  characterized in that the vessel is made of polytetrafluoroethylene, in particular of a copolymerized polytetrafluoroethylene. 9. Device according to one of claims 1 to 7, characterized by a seal (31) for sealing a gap, wherein the seal (31) is made of perfluoroelastomer. 10. A device for mixing liquid, comprising:  - A vessel (2) with an interior (3) for receiving liquids  a first dosing liquid discharge device (30) for injecting liquid to be mixed into the interior space,  characterized in that the first dosing liquid discharge means comprises an end piece which is in the form of a tube and the orientation of the tube of the end piece is at an angle greater than 5 degrees to the vertical. 1 1. Apparatus according to claim 10, characterized by  - A second Dosierflüssigkeitsablassvorrichtung for dropping liquid to be mixed into the interior, wherein the first Dosierflüssigkeitsablassvorichtung (30) has an end piece (310) which has the shape of a tube and the alignment of the tube of the tail at an angle of greater than 5 degrees to the vertical stands.