WO2013159791A1 - Metering device, counting device, metering process and counting method - Google Patents

Metering device, counting device, metering process and counting method

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Publication number
WO2013159791A1
WO2013159791A1 PCT/EP2012/001786 EP2012001786W WO2013159791A1 WO 2013159791 A1 WO2013159791 A1 WO 2013159791A1 EP 2012001786 W EP2012001786 W EP 2012001786W WO 2013159791 A1 WO2013159791 A1 WO 2013159791A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
liquid
opening
metering
chamber
pressure
Prior art date
Application number
PCT/EP2012/001786
Other languages
German (de)
French (fr)
Inventor
Robert Rieger
Original Assignee
Testo Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/28Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/40Concentrating samples
    • G01N1/4005Concentrating samples by transferring a selected component through a membrane
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01FMEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F13/00Apparatus for measuring by volume and delivering fluids or fluent solid materials, not provided for in the preceding groups
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials

Abstract

In a metering method for providing a metered quantity of a liquid the invention proposes forming an inlet opening (3), an outlet opening (4) and a porous wall region (8) with an external removal opening (9) on a metering chamber (5), and applying a first pressure difference between the inlet opening (3) and the outlet opening (4) in order to transport a liquid from a reservoir (12), externally connected to the inlet opening, to the outlet opening (4), and at the same time applying a second pressure difference between the removal opening (9) and the inlet opening (3) in order to divert some of the liquid (7), which is flowing in through the inlet opening, via the porous wall region (8) out of the metering chamber (5) until the reservoir (12) and the metering chamber (5) are emptied, wherein the metered quantity of the liquid has exited the outlet opening (4) and is in readiness after termination of the process.

Description

Metering, counting, dosing and counting procedures

The invention relates to a metering device with a an inlet opening and an outlet opening having metering chamber, wherein a first means for applying a first pressure differential is formed between the inlet port and the outlet port to a dosed amount of air flowing in through the inlet port fluid through the metering chamber the outlet to promote. The invention further relates to a counting device for determining a volume-related or absolute number of particulate constituents in a liquid.

The invention further relates to a metering method for metering a fluid, wherein a first pressure difference between an inlet opening and an outlet opening of a metering chamber is applied in order to promote a dosed amount of inflowing liquid through the inlet port through the metering chamber to the outlet port.

Finally, the invention relates to a counting method for determining a volume-related or absolute number of particulate constituents in a liquid. There are known metering devices in which the amount to be dosed is determined by the volume of the metering chamber. In these metering devices, the metering chamber will be completely filled with the liquid, and the amount to be dispensed is obtained by removal of the pre-held in the metering chamber contents. Here, it is necessary to monitor the complete filling of the metering chamber and the complete emptying to actually get the metered amount.

There are further known metering devices in which the amount to be dosed is formed by pulsed valves. In these metering a quantity to be metered can be determined by the clocked valves are opened in a predetermined time interval at a known volume flow rate of the liquid. To actually determine the amount defined, precise adjustment of the pressure difference or a measurement of the flow rate is required. The object of the invention is based, to achieve a dose of a liquid with a minimum of equipment cost.

To achieve this object it is proposed according to the invention at a dosing device of the type described at the outset, that the metering chamber has a porous wall portion, the porous wall region externally forming a removal opening, and that off a second means for applying a second pressure differential between the discharge port and the inlet port formed is to divert a portion of the inflowing liquid through the inlet port through the removal opening. , Is of advantage that a distinct, unknown volume of a liquid, the metering chamber is fed through the inlet opening, wherein in an intermediate state in the promotion of the flowing liquid, a state of equilibrium between the incoming liquid and the diverted through the removal opening fluid is reached by the dosing chamber, which reduces the unknown volume in an exactly defined amount of fluid in the metering chamber. Thus, a dosage can proceed without an active control, and there are no moving parts such as valves and the like required clocked. Any volume of liquid can be reduced to a predetermined volume, provided that it is sufficiently larger than this predetermined volume. More specifically, it can be provided that the input volume is larger than the predetermined volume plus an amount that is sucked through the porous wall portion. The invention provides the further advantage that no monitoring by sensors and no active manipulation of the volume flow of the liquid through the metering chamber is required. Thus, the apparatus required for dosing is very low. Preferably, the porous wall portion in flow or the conveying direction between the inlet opening and the outlet opening is arranged.

In one embodiment of the invention, it can be provided that the inlet opening is connected to a distinct or definable reservoir. , Is of advantage that a delimitable volume of liquid can be supplied, which is according to the invention can be reduced to the predetermined volume.

Preferably, it is provided that this predetermined volume and in particular the amount to be dispensed is less than a volume of the metering chamber. The air supplied through the inlet opening amount can be of any size, in particular larger than the predetermined volume plus the sucked in operation through the porous wall region amount.

Under a porous wall portion, a wall portion is meant having the wall traversing pores, the pores preferably are dimensioned so that capillary effects occur and / or the pores remain filled with liquid due to the capillary phenomenon, even if the metering chamber is emptied. the porous wall portion of a material is preferably formed, which is wetted by the measurable liquid. This can be given in that the porous wall portion having a contact angle of less than 90 ° with this liquid. For example, the porous wall portion in the case of water can be used as a hydrophilic membrane may be formed in the case of non-polar liquids as a hydrophobic membrane. The pore size can in this case regulate the strength with which the fluid is retained in the pores by capillary action,. Here applies, for example, that the more pressure has to be applied, the smaller the pores in order to empty the pores.

With the outer side forming the removal opening is achieved that the clothes Entnahmeöff be separated through the porous wall portion of the metering chamber. Thus is effected with the second pressure difference, a removal of the portion of the inflowing liquid through the inlet opening through the porous wall region therethrough.

The porous wall portion and / or the metering chamber may / may be made for example by injection molding or hot embossing. -Consuming post-processing steps after the production are not required.

It may also be envisaged that the porous wall portion is formed by a preferably hydrophilic membrane. This is favorable, for example, when the liquid is an aqueous (polar) solution is. It may also be envisaged that the porous wall portion is formed by a hydrophobic membrane. This may be advantageous, for example if the liquid is a non-polar solution.

In one embodiment of the invention it can be provided that the porous wall portion over a length of the metering chamber between the inlet port and the outlet port extends. This may provide that the metering chamber is dimensioned as small as possible is advantageous. It is further achieved that the liquid flowing with increasing filling of the metering chamber contacted by an increasing share of the porous wall portion or cover, whereby, a greater proportion of the inflowing liquid through the inlet port through the removal opening can be branched off. It can also be provided that the porous wall portion extending over a a connecting line between the inlet opening and the outlet opening circumferential periphery of the metering chamber. It is advantageous in that proportions of the inflowing liquid through the inlet opening on all sides transversely to the connecting line branched off. In this way the length of the porous wall portion is as low as possible selectable longitudinally to the connecting line between the inlet port and the outlet port. Thus, a minimal dimensioning of the metering chamber is achievable.

In one embodiment of the invention, can be provided that a receiving space is formed at the outside of the porous wall portion. This may provide that the branched-off portion of the incoming liquid can be received over a longer period of benefit.

it when the receiving space is filled with a liquid-sigkeitsabsorbierenden, air-permeable material is particularly favorable. , Is that the applied second pressure difference is independent of the level of the Aufnähmeraums be applied advantage. For example, the material may be a superabsorbent polymer.

In the embodiment of the invention that has a pore size and choice of material are matched to the second pressure difference, that the second pressure differential is smaller than a capillary pressure in the porous wall portion can be provided. , Is that then the second pressure differential is not sufficient to empty the pores of the porous wall portion of liquid when the inner region of the metering chamber is free of liquid is advantageous. Thus, it is achieved in a simple manner that the porous wall portion is hermetically sealed with unfilled or emptied metering chamber.

Generally, it can be provided in embodiments of the invention, that the first means comprises a device for generating a negative pressure, which is connected to the outlet or connected.

For example, it may be provided in an embodiment of the invention that the device for generating a negative pressure by an evacuated chamber, a centrifuge, or arranged at different heights vessels is set up.

In one embodiment of the invention it can be provided that the first means comprises a first pump which is connected to the outlet opening. , Is of advantage that a negative pressure can be applied, with which the incoming liquid can be conveyed. Generally, it can be provided in embodiments of the invention that the second means comprises a device for generating a negative pressure which is connected to the Entnahrneöfnung. For example, this can be a centrifuge, an evacuated chamber or there may be arranged at different heights container or the like may be formed.

It may be provided that the device for generating a negative pressure of the first means is formed separately from the device for generating a negative pressure of the second agent, or that the device for generating a negative pressure of the first agent identical to the apparatus for generating a negative pressure of the second is using.

In further embodiments, the first means for applying a first pressure differential and / or the second means for applying a second pressure differential may comprise means for applying a positive pressure at the inlet port.

In one embodiment of the invention it can be provided that the second means comprises a second pump which is connected to the removal opening. , Is that a negative pressure relative to the inlet port to the detection port Entnah- can be applied, with which liquid from the dosing chamber through the porous wall portion is conveyed beneficial.

it, when the first pump and the second pump are the same is particularly favorable. , Is that only one pump is required beneficial. Pressure variations due to uneven operation of the pump thus do not affect or only slightly, the operation of the dosing device. It can also be provided that the first pressure difference is equal to the second pressure difference. , Is that pressure fluctuations that may occur in a vacuum applied, compensate mutually advantageous.

In one embodiment of the invention, it can be provided that a length of the porous wall portion is aligned along a connecting line between the inlet opening and the outlet opening in such a manner on the first pressure difference and second pressure difference that for a given filling level of the metering chamber a balance between pro time unit entering through the inlet opening amount of liquid and is a unit of time through the removal opening branched amount of liquid adjusted until an externally connected to the inlet reservoir is emptied. Here, the metering chamber with liquid can be filled with the first pressure differential, while the second pressure differential causes a withdrawal of liquid from the metering chamber through the porous edge region and the removal opening. The per time unit removable from the dispensing opening amount of liquid depends on the second pressure difference and the size of which is in contact with the liquid in the pressure chamber face of the porous wall portion. The larger this surface is, the more amount of fluid can be removed per unit time. If the length of the porous wall region selected to be sufficiently large along a connecting line between the inlet port and the outlet port, so a state of equilibrium can be achieved, by which the whole inflowing

Amount of liquid through the discharge opening can be discharged. Thus is achieved that excess liquid in the reservoir can be removed independently of the initial volume of liquid, without a quantity of liquid or a period of time must be monitored. In one embodiment of the invention, it can be provided that the first pressure difference is matched to the second pressure difference that, in the deflated reservoir an amount of fluid contained in the metering chamber is at least partially transported to the outlet opening. Here, the first difference in pressure causing a promotion of fluid in the metering chamber to the outlet, while the second pressure differential causes a promotion of liquid from the metering chamber through the porous wall portion. causes an increase in the first pressure difference that more liquid is transported to the outlet opening. A magnification of the second pressure difference causes the other hand that more liquid is removed through the porous wall portion. In a certain range of the ratio of the first pressure differential to the second pressure difference, a defined proportion of an amount of fluid contained in the metering chamber through the outlet port is thus transported away. Thus is achieved that a defined portion of a reduced to a predetermined volume liquid keitsmenge from the dosing chamber through the outlet port can be discharged.

The metering device according to the invention is according to the invention applicable to a described initially counting device in which a metering device according to the invention, in particular as described above and / or according to any one of claims 1 to 9 are present, wherein to the outlet opening of the metering device a measuring device is connected, wherein the measuring device is arranged to measure a measurement variable which is dependent on the number of particulate constituents in an emerging from the outlet opening of the metering liquid. , Is of advantage that, to be metered amount of liquid can be provided with the metering device defined at which a volume-related quantity and / or a total number can be measured in a total amount of liquid supplied from particulate constituents.

To determine the absolute number may be provided, that the porous wall region for the particulate components is impermeable. Thus, a concentration of the particulate components in the metering chamber is feasible, in particular before the count of the particulate components.

For example, the measured quantity can be connected to an intensity of a scattered light and / or a portion in a certain way polarized radiation and / or other physical measuring quantity, which, for example, by a method from the group of transmitted light method, light scattering method, fluorescence method for characterizing the number of particulate constituents in a liquid can be measured, be. To achieve the above object, the invention provides for a metering of the type described at the outset, that the metering chamber has a porous wall portion having an outside formed on the porous wall portion removal opening, and that during the transport of the fluid from the inlet port to the outlet port, a second pressure differential between the inlet opening and the removal opening is designed to branch a part of the air flowing in through the inlet port fluid via the dispensing opening of the metering chamber. Here, the turn-off on the removal opening is preferably carried out continuously. is of advantage that an equilibrium which is established at a certain filling level of the metering chamber between the inflow through the inlet liquid and the voltage on the Entnahmeöff- removed or branched liquid, defined in a for the reduction of an unknown, supplied via the inlet port fluid volume is available volumes.

Definition of the total volume of liquid supplied can be provided that the liquid is pumped from a reservoir connected to the inlet opening in the dosing chamber. Here, the reservoir may be formed distinguishable in the sense defined or that the provided in the reservoir volume of liquid is separated from the environment. The exact amount of fluid volume provided does not have to be known. In one embodiment of the invention that the method is terminated when the reservoir and / or the metering chamber is emptied / are can be provided.

It is advantageous that no additional termination criterion must be monitored. Since the process is terminated automatically when the reservoir and the metering chamber are discharged, and thus no further liquid can be fed and the outlet port is supplied. In one embodiment of the invention that the dosing chamber is being filled through the inlet opening up to a predetermined level in a first part step can be provided. , Is that a portion of the porous wall portion is defined by the predetermined level, that is with the liquid contacting is advantageous. This percentage specifies how much liquid over the removal opening can be branched off. Preferably, therefore, the predetermined level is set so that a portion of the porous wall portion is covered with the liquid in the metering chamber or is in contact, and another portion of the porous wall portion is not.

but it can also be provided, is that the predefined filling level selected such that the porous wall region completely covered with liquid in the metering chamber or is in contact.

In one embodiment of the invention that in a second partial step, a per unit time entering through the inlet opening amount of liquid is completely discharged through the discharge port or suction, to a device connected to the inlet opening of the reservoir is depleted can be provided. Preferably, it is provided that the second partial step adjoins the aforementioned first sub-step and / or that the second sub-step is performed when the metering chamber is up to the predetermined level or filled with liquid. The adjustment of the equilibrium described between the incoming amount of liquid and the discharged amount of liquid through the removal opening advantageous effect that an unknown volume of fluid can be reduced until the reservoir is emptied. Hereby is achieved that the amount of liquid located at the end of the second step in the metering chamber is independent of the originally present in the reservoir volume of liquid.

In one embodiment of the invention can be provided that partially diverted in a third partial step, a loading-sensitive in the dosing amount of liquid through the removal opening, and partially transported to the metering chamber to the outlet port, wherein a total transported to the outlet of liquid as a metered amount of the liquid- sigkeit is provided. Preferably, it is provided that the third sub-step connects to the previously described first or second sub-step and / or that the third sub-step is performed after the or a device connected to the inlet opening of the reservoir has been emptied. This configuration of the third part of step offers the advantage that a reduced in the metering chamber to a defined amount of liquid volume can be discharged from the outlet proportionally. Thus, the desired in the metering metered quantity is simple providable without additional apparative means are required.

In one embodiment of the invention that the branched-off through the porous wall region of the liquid outside the removal opening is absorbed by an absorbent, air permeable material may be provided. , Is that the second pressure difference is maintainable regardless of the removed through the removal opening amount of liquid in a simple manner beneficial. Preferably Provision is made for the material is a super absorbent polymer.

In one embodiment of the invention that the second pressure difference is set equal to the first pressure differential may be provided. , Is that the on apparatus rative effort for the implementation of the dosing method is again reducible beneficial. An advantage is further that variations in the pressure differences provided automatically compensate. In one embodiment of the invention that the second pressure differential is smaller than a capillary pressure is set in the porous wall portion can be provided. that the porous wall area remains mer airtight even when emptied Dosierkam- is advantageous in this regard. Thus is avoided that the porous wall portion facing one of the inlet opening end of a quantity of liquid for air in the metering chamber may be permeable, whereby the first pressure difference would coincide. It is thus achieved that the metering chamber for the purposes of transportation of a liquid slug acts as a closed tube to the outlet opening, wherein additionally a portion of the liquid of the plug is removed during transport through the porous wall portion and is taken out.

The dosing method according to the invention is applicable to advantage in a counting method of the type described, wherein a metered quantity of a liquid with a erfindungsge- MAESSEN metering, and is especially as described above and / or provided any one of claims 11 to 16 wherein the dose of amount of a measured variable, which are dependent on the number of particulate constituents in an emerging from the outlet opening of the metering device is pending liquid is measured. For example, the measured variable in at least one method or more methods from the group lookup method, light scattering method, fluorescence method can be measured. , Is that a volume-based number of particulate components in a liquid with relatively low expenditure on apparatus is feasible beneficial.

This configuration of independent inventive significance thus advantageously utilizes that at the output of a defined volume of liquid leaves the metering chamber. By measuring where the number of particulate ingredients, one has determined the concentration of the starting solution. Thus, there is a volume-based number. Alternatively or additionally, however, a number of particulate constituents in the starting solution can be determined, for example, when the porous wall portion is impermeable to the particulate components. It can thus take place up concentration of the particulate constituents in the metering chamber. This is particularly advantageous when the measurement method for the starting solution, for example in one or the reservoir, a long time would take. The reduced volume with the invention, after passing through the metering device leads to a saving of time during the measurement.

The invention will now be described in detail based on an embodiment, but is not limited to this embodiment. Further embodiments result from combination of individual or several features of the protection claims among each other and / or with one or more features of the embodiment.

It shows in a very simplified diagram explaining the inventive principle

Fig. 1 is a counting device according to the invention with a metering device according to the invention in a first partial step of a dosing method according to the invention,

Fig. 2, the counting means and metering device according to Fig. 1 in a second partial step of the dosing method according to the invention and

Fig. 3, the counting and metering device according to Fig. 1 in a third sub-step of dosing method according to the invention.

Fig. 1 is a designated as a whole with 1 counter. The counting device 1 has a metering device 2, which has an inlet opening 3 and an outlet opening. 4

Between the inlet opening 3 and outlet opening 4, a metering chamber 5 is formed.

With a first means 6 a negative pressure to the outlet opening 4 can be applied, through which a pressure difference between the inlet opening 3 and the outlet port is applied. 4 By this pressure difference can be a flowing liquid 7 to be at least partially supported by the dosing chamber 5 to the outlet opening. 4 This is explained in more detail below.

The metering chamber 5, between the inlet opening 3 and the outlet 4 to a porous wall portion. 8

a removal opening is formed on the outside 9 and disposed on the porous wall portion. 8 The porous wall portion 8 thus defines a diversion from the conveyance path between the inlet opening 3 and the outlet 4 to the removal opening.

At the discharge opening a second means 10 is connected with which a negative pressure can be developed at the removal opening. 9 This negative pressure causes a pressure difference between the discharge opening 9 and the inlet opening 3. This second pressure differential causes a portion 11 of the flowing liquid 7 is branched off through the porous wall region 8 of the metering chamber. 5 To the inlet port 3, a reservoir 12 is externally connected.

The reservoir 12 is defined or delimited, to accommodate any but delimited liquid volume.

The porous wall portion 8 has a plurality of pores. 13 The pores 13 are formed with a diameter at which the capillary forces cause in the pores 13 does not leak liquid absorbed by itself. Here, the porous wall portion 8 is formed of a material which is wetted by the measurable liquid, ie has a contact angle of less than 90 ° with this liquid.

The liquid is water or any other polar liquid used, it is in the porous wall portion to a hydrophobic membrane or a hydrophobic material.

In the case of non-polar liquids, the porous wall portion 8 of a hydrophobic membrane or of a hydrophobic material is formed. Over the pore size is in this case the strength with which the fluid is retained in the pores 13 of the capillary effect, set or predetermined. The smaller the pores 13 are, the more pressure must be applied in order to empty the pores. 13

The porous wall portion 8 can be arranged interchangeably in order to make the metering device 2 adapted to different liquids and / or different second pressure differentials.

The porous wall portion 8 extends over the entire length of the metering chamber 5 between the inlet opening 3 and the training outlet opening 4. In further embodiments, the porous wall portion 8 may have a shorter length than the metering chamber. 5

In the embodiment shown in FIG. 1 to FIG. 3, the porous wall portion 8 is formed at one side of the metering chamber. 5

However, it can also be provided that the porous wall portion 8 extends ER- on all sides or on all sides of the metering chamber. 5 In this case, the porous wall portion 8 thus 8 extends over a connecting line between the inlet opening 3 and the outlet 4 circumferential periphery of the dosing chamber 5. In the embodiment according to FIGS. 1 to 3 and also in further embodiments is on the outside of the porous wall portion a receiving space 14 is formed and arranged. The Au receiving space 14 serves for receiving the branched portion 11 of the incoming liquid. 7

The receiving space 14 is filled with a not further apparent superabsorbent polymer as a liquid, air-permeable material. The developed across the second means 10 under pressure can be supplied to 9 thus independent of the filling quantity in the receiving space 14 of the Entnahmeöff ung to set a constant second pressure differential.

The first means 6 and the second means 10 have a common pump 15th

In further embodiments, the first means 6 and the second means 10 each have a pump at the point indicated by 15 in Fig. 1 to 3. These can be formed separately from each other completely or integrated in a common housing. These separately operable pumps 16 and 17 different negative pressures can be applied to the channels.

In further embodiments may be achieved by other means and adapted to a different vacuum at the channel 16 can be applied to the first means 6 and is applied as the means 10 to the channel 17th

It will become apparent to the divergent suppressing corresponding, differing pressure differences with respect to the inlet port 3. The pump 15 in Figure 1 to 3 creates a negative pressure which is supplied through an intake passage 16 of the first means 6 of the outlet opening. 4

The second means 10 includes an intake passage 17, through which the developed by the pump 15 under pressure of the removal opening is supplied. 9

Each mediated negative pressures are equal, so that the first pressure difference is equal to the second pressure difference.

In the above-mentioned other embodiments, the first pressure differential is set different from the second pressure differential. With the metering device 2, a metering for metering a liquid can be executed, which will be described in more detail below with reference to FIGS. 1 to 3.

With the means 6, a first pressure differential between the inlet opening 3 and the outlet 4 is applied in order to promote in the dosing chamber 5, a flowing liquid. 7 The incoming liquid 7 is in this case taken from a device connected to the inlet opening 3 reservoir 12th

In a first partial step, which is illustrated in Fig. 1, the metering chamber is moved up by the inflowing liquid 7 due to the first pressure difference filled.

It can be seen in Fig. 1, that is changed by this filling of the filling level in the dosing chamber 5 so that an increasing proportion of the porous wall portion 8 is covered with LIQUID from the dosing chamber 5, or come into contact.

The liquid flowing in the metering chamber 7 forms a 5 front liquid meniscus 22, which moves in Figure 1 with the progress of filling level in the dosing chamber 5 to the right.

The same time through the second means 10 applied negative pressure causes a pressure difference between the inlet opening 3 and the discharge opening 9, through which a part of the liquid 7 is inflowing through the porous wall region 8 removed from the dosing chamber 5. 11

It can be seen that with progressive filling of the metering chamber 5 an increasingly larger area of the porous Wandbe ¬ Reich 8 is covered with liquid from the dosing chamber 5, or come into contact so that a larger and larger portion 11 of the flowing liquid 7 not to the outlet port 4 but is discharged through the discharge opening. 9

Simultaneously to the hydrodynamic resistance increases according to Hagen-Poiseuille, which counteracts the flow in the metering chamber, with increasing filling of the dosing chamber as well.

The inflowing fluid 7 therefore fills the dosing chamber 5, to a state shown in Fig. 2 equilibrium state is reached. For this purpose, the fluid conductivity of the porous wall portion 8 as well as width, depth and length of the metering chamber 5 are chosen so that the equilibrium state is established. It further parameters are also adjusted accordingly, so that the state of equilibrium at the desired position. These include the surface of the porous wall region 8 on the one hand and the difference in the pressure differences at the outlet opening 4 and the removal opening 9 with respect to the Einlassöff ung applied 3 when these pressure differences differ as described, on the other hand. In this equilibrium state, which is characterized by attaining a predetermined level 18, also equilibrium level, delivers the incoming liquid 7 completely through the porous wall portion 11 into the receiving chamber 14 from. The characterized by the predetermined level 18 front liquid meniscus 22, the liquid-air boundary, moves not in equilibrium forward.

This is the beginning of the second step of Dosierverfah- proceedings.

This state of equilibrium, wherein the level 18 is not changed, continues until the reservoir 12 is completely emptied. Here, the front liquid meniscus 22 remains at the position shown in Fig. 2 in the metering chamber. 5

The branched-off via the discharge opening 9 part 11 of the inflowing liquid 7 is taken up in an absorbent material in the receiving space fourteenth This material, which is not further shown in the figures for simplicity of illustration, retains its air-permeable properties even after absorption of the liquid. Thus, the second pressure difference remains between the inlet opening 3 and the discharge opening 9 is constant and independent of the received in the receiving space 14 of liquid.

In further embodiments, the receiving space 14 is formed without an absorbent material. The receiving space 14 is in this just very large, for example with a very small hydrodynamic resistance designed. Also, it can be achieved that the second pressure difference remains with progressive filling of the receiving chamber 14 is approximately or exactly constant.

Once the reservoir 12 is completely emptied, the third sub-step of the metering process, which is shown in Fig. 3 schematically begins.

In this step, the part in contact with the liquid from the dosing chamber 5 face of the porous wall portion 8. Thus, the decreased recoverable through the porous wall region 8 liquid amount decreases again, so that the balance is left in FIG. 2.

This means that the level of the liquid in the metering chamber 5 rises again. However, no more liquid flows through the by Einlassöff ung 3, so that the amount of liquid still present in the dosing chamber 5 forms a quantity of liquid 19 in the form of a plug, which is transported to the outlet opening. 4

In the third step, a rear part of liquid meniscus 23 forms on the back of the remaining amount of liquid in the metering chamber 5 19 as the liquid-air boundary. The front liquid meniscus 22 continues in the third sub-step moving again.

At the same time, the rear liquid meniscus 23 also moves in the dosing chamber 5, since no more liquid nachströmt through the inlet opening. 3

During transport, a portion 20 of the transported to the outlet 4 amount of liquid is further branched off through the porous wall region 8 nineteenth Therefore, the amount of liquid 19 reduced in size during transport to the outlet opening 4 by a defined percentage.

During transport, therefore, the rear liquid meniscus 23 and the front liquid meniscus 22 approach each other.

In the area behind the quantity of liquid 19, between the remaining amount of liquid and the inlet opening 3, the porous wall portion 8 is no longer with the liquid in the metering chamber 5 in contact.

Here, in the no longer in contact with the liquid in the metering chamber 5 portion of the porous wall region 8 of the capillary forces in the pores 13 ensure that the porous wall portion 8 remains airtight. This prevents the second pressure difference between the inlet opening 3 and the removal opening is shorted 9, which would result in a collapse of the first pressure differential between the inlet opening 3 and the outlet opening. 4

Once the amount of liquid left 19, the dosing chamber 5, the metering process is completed, and the remaining amount of liquid 19 forms the metered amount.

This metered quantity can be supplied in the inventive application in an inventive method of counting a merely indicated measuring device 21 of a known type which is adapted for example for carrying out a transmitted light method and / or a scattered-light method and / or a fluorescence method.

With the measuring device 21 can measure and is now a measure of Ge, which is dependent on the number of particulate constituents in the emerging from the outlet opening 4 amount of liquid 19th can from this measure and calculated the number needed after and based on the volume of the amount of the amount of liquid 19 defined.

It should be noted that in the described metering takes place a concentration of those ingredients in the measurable liquid or solution at the same time, which can not pass through the porous wall portion. 8 This is for example useful to measure an absolute number of partiku ¬ lar components in a large amount of liquid by the large amount of liquid is reduced by the method described before the count or number determination. Here, the porous wall portion 8 is impermeable to the particulate ingredients to be counted.

The dosing and the dosing described are suitable for repeated executions. In this case, several volumes of liquid that are the reservoir one after another and separated from each other, supplied, can be reduced with the proposed inventive dosing in each case to the desired amount or measured.

In the metering process for providing a metered amount of a liquid it is proposed that in a metering chamber 5 has an inlet opening 3, an outlet 4, and a porous wall portion 8 with an outside discharge opening 9, and between the inlet opening 3 and applying a first pressure difference of the discharge port 4 to to transport a liquid from an externally connected to the inlet reservoir 12 to the outlet port 4, and at the same time between the withdrawal opening 9 and to apply a second pressure difference between the inlet port 3 in order from a part of the air flowing in through the inlet opening liquid 7 through the porous wall region 8 to branch off the dosing chamber 5, until the reservoir 12 and the metering chamber is emptied 5, wherein the metered amount of fluid has leaked and after completion of the procedure at the outlet opening 4 is provided.

Claims

claims
Metering device (2), with a an inlet aperture (3) and an outlet (4) having metering chamber (5), wherein a first means (6) for applying a first pressure differential between the inlet opening (3) and the outlet opening (4) formed to flowing a dosed amount of a through the inlet port (4) liquid (7) to promote the outlet opening (4) through the dosing chamber (5), characterized in that the dosing chamber (5) comprises a porous wall region (8), is formed that the porous wall region (8) on the outside forms a removal opening (9) and that a second means (10) for applying a second pressure difference between the removal opening (9) and the inlet opening (3) to a part (11) by the inlet port flowing (3) liquid (7) through the removal opening (9) branch off.
Metering device (2) according to claim 1, characterized in that the inlet opening (3) to a closed or lockable reservoir (12) is connected.
Metering device (2) according to claim 1 or 2, characterized in that the removal opening (9) through the porous wall region (8) of the dosing chamber (5) is separated and / or that the porous wall region (8) is formed by a membrane.
Metering device (2) according to one of claims 1 to 3, characterized in that the porous wall region (8) over a length of the metering chamber (5) between the inlet to outlet opening (3) and the outlet (4) and / or that the porous wall region (8) via a connecting line a between the inlet opening (3) and the outlet (4) circumferential periphery of the metering chamber (5).
Metering device (2) according to one of claims 1 to 4, characterized in that on the outside of the porous wall portion (8) a receiving space (14) is formed and / or that the receiving space (14) with a liquid-keitsabsorbierenden, air-permeable material, is filled in particular a superabsorbent polymer.
Metering device (2) according to one of claims 1 to 5, characterized in that a pore size and choice of material are matched to the second pressure difference, that the second pressure differential is smaller than a capillary pressure in the porous wall region (8).
Metering device (2) according to one of claims 1 to 6, characterized in that the first means (6) comprises a first pump (15) which is connected to the outlet opening (4), and / or that the second means (10) a second pump (15), which is connected to the removal opening (9).
Metering device (2) according to one of claims 1 to 7, characterized in that the first pump (15) and the second pump (15) are identical and / or that the first pressure difference is equal to the second pressure difference.
Metering device (2) according to one of claims 1 to 8, characterized in that a length of the porous wall region (8) along a connecting line between the inlet opening (3) and the outlet opening (4) in such a manner on the first pressure difference and second pressure difference is tuned to at a predetermined level (18) of the metering chamber (5), a balance between a per unit of time through the inlet opening (3) entering liquid amount and a unit of time through the discharge opening (9) is set branched liquid quantity until the outside of the inlet port (3) connected reservoir (12) is emptied, and / or that the first pressure difference is matched to the second pressure differential amount of liquid that contained a in the metering chamber (5) with deflated reservoir (12) (19) at least partially to outlet opening (4) is transportable.
Counting means (1) for determining a volume-related or absolute number of particulate constituents in a liquid, characterized in that a metering device (2) according to any one of claims 1 to 9 is provided and that the outlet opening (4) of the metering device (2) a is connected to measuring device (21), wherein the measuring device (21) for measuring a measured variable, the exiting of the number of particulate constituents in an out of the outlet opening (4) of the metering device (2) amount of liquid (19) is dependent is set up.
Dosing method for dosing a liquid, wherein a first pressure difference between an inlet opening (3) and an outlet (4) of a metering chamber (5) is applied to flowing a dosed amount of a through the inlet port (3) liquid (7) through the dosing chamber to promote (5) to the outlet opening (4), characterized in that the dosing chamber (5) comprises a porous wall region (8) formed with the outside of the porous wall region (8) removal opening (9) up has and that during the conveying the liquid from the inlet opening (3) to the outlet opening (4) is applied a second pressure difference between the inlet opening (3) and the removal opening (9) for flowing a portion (11) through the inlet opening (3) liquid (7) preferably continuously branched off via the removal opening (9) from the dosing chamber (5).
Dosing method according to claim 11, characterized in that the incoming liquid (7) from a device connected to the inlet opening of the reservoir (12) into the metering chamber (5) conveyed and / or that the method is terminated when the reservoir (12) and / or the dosing chamber (5) is emptied / are.
Dosing method according to claim 11 or 12, characterized in that in a first partial step, the metering chamber (5) through the inlet opening (3) is filled to a predetermined level (18) and / or that in a second partial step, particularly if the dosing chamber ( 5) up to the or a predetermined fill level (18) filled with liquid, is discharged entering a per unit time (through the inlet port 3) amount of liquid completely (through the discharge opening 9), or suction, to a (at the inlet port 3) connected reservoir (12) is emptied.
14. metering process according to any one of claims 11 to 13, characterized in that the amount of liquid contained in a third partial step, particularly after or at the inlet opening (3) connected reservoir (12) has been emptied one in the metering chamber (5) (1 wherein one (to the outlet opening 4) a total amount of transported liquid is provided as a metered amount of the liquid) is partially branched off through the removal opening (9) and partly in the metering chamber (5) to the outlet opening (4) transported.
5. metering process according to any one of claims 11 to 14, characterized in that the through the porous wall region (8) branched-off part (11) of the liquid outside the removal opening (9) is absorbed by an absorbent, air permeable material, in particular a superabsorbent polymer, ,
6. metering process according to any one of claims 11 to 15, characterized in that the second pressure difference is set equal to the first pressure difference and / or that the second pressure difference is set smaller than a capillary pressure in the porous wall region (8).
7. The counting method for determining a volume-related or absolute number of particulate constituents in a liquid, characterized in that a metered quantity of a liquid with a metering process according to any one of claims 11 to 16 provided and that on the metered quantity of a measured variable, by the number of particulate constituents in the metered quantity depends, is measured.
PCT/EP2012/001786 2012-04-26 2012-04-26 Metering device, counting device, metering process and counting method WO2013159791A1 (en)

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Citations (2)

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Publication number Priority date Publication date Assignee Title
US20070151924A1 (en) * 2005-12-29 2007-07-05 Spf Innovations, Llc Method and apparatus for the filtration of biological samples
US20090101575A1 (en) * 2007-05-30 2009-04-23 Alburty David S Liquid To Liquid Biological Particle Concentrator

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070151924A1 (en) * 2005-12-29 2007-07-05 Spf Innovations, Llc Method and apparatus for the filtration of biological samples
US20090101575A1 (en) * 2007-05-30 2009-04-23 Alburty David S Liquid To Liquid Biological Particle Concentrator

Non-Patent Citations (1)

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