Degassing apparatus

Abstract

The invention relates to an apparatus having a pressure chamber and a micropump in fluid connection with the pressure chamber. The pressure chamber includes a gas-carrying region and a liquid-carrying region. The micropump is configured to generate a pneumatic pressure within the gas-carrying region that is lower than a fluid pressure of a liquid flowing through the liquid-carrying region. According to the invention, a gas-permeable and liquid-impermeable separating element separates, at least in sections, the gas-carrying region and the liquid-carrying region. According to the present invention, the micropump is disposed on the pressure chamber.

Claims

1. Apparatus, comprising a pressure chamber and a micropump in fluid connection with the pressure chamber, wherein the pressure chamber comprises a gas-carrying region and a liquid-carrying region, wherein the micropump is configured to generate a pneumatic pressure within the gas-carrying region that is lower than a fluid pressure of liquid flowing through the liquid-carrying region, and wherein a gas-permeable and liquid-impermeable separating element separates the gas-carrying region and the liquid-carrying region from each other at least in sections, wherein the micropump is disposed on the pressure chamber and the liquid-carrying region is a tube conduit running within the pressure chamber, wherein the tube conduit comprises, at least in sections, a material forming the gas-permeable and liquid-impermeable separating element, and wherein the micropump is configured to generate a negative pressure of −30 kPa to −55 kPa with respect to atmospheric pressure in the gas-carrying region of the pressure chamber.

2. Apparatus according to claim 1, wherein the tube conduit is disposed in the pressure chamber in a spiral shape.

3. Apparatus according to claim 1, wherein the micropump comprises a stroke volume per pump stroke of 50 μl or less.

4. Apparatus according to claim 1, wherein the micropump is mounted on the pressure chamber by means of screws and/or clamps.

5. Apparatus according to claim 1, wherein the micropump is mounted on the pressure chamber by means of adhesive or solder.

6. Apparatus according to claim 1, wherein the apparatus comprises a liquid-delivering pump by means of which liquid can be delivered through the liquid-carrying region or wherein the micropump is configured to deliver liquid through the liquid-carrying region.

7. Apparatus according to claim 6, wherein the apparatus comprises a pressure sensor fluidically coupled to the gas-carrying region and a control connected to the pressure sensor and the liquid-delivering pump, wherein the control is configured to control the liquid-delivering pump in dependence on a signal of the pressure sensor such that the delivery rate of the liquid-delivering pump is increased until the pressure within the gas-carrying region reaches a threshold and/or such that the delivery rate of the liquid-delivering pump is lowered at a pressure exceeding a threshold within the gas-carrying region.

8. Apparatus according to claim 1, wherein the apparatus further comprises a pressure sensor fluidically coupled to the gas-carrying region and a control connected to the pressure sensor, wherein the control is configured to control the micropump in dependence on a signal of the pressure sensor such that the micropump is switched on when the pressure within the gas-carrying region of the pressure chamber rises above a threshold.

9. Apparatus according to claim 1, wherein the apparatus comprises a temperature regulation apparatus that is configured to cool the gas-carrying region and/or to heat the liquid-carrying region.

10. Apparatus according to claim 1, wherein the apparatus comprises a valve fluidically coupled to the gas-carrying region connected to a strip gas-carrying conduit in order to introduce a strip gas into the gas-carrying region of the pressure chamber.

11. Apparatus according to claim 1, wherein optical or capacitive gas bubble detectors are provided within the pressure chamber or in flow direction of the liquid in front of the pressure chamber, which are configured to detect a gas bubble in the liquid and wherein the apparatus further comprises a control that is configured to switch on the micropump in dependence on a detected gas bubble.

12. Apparatus according to claim 1, wherein the liquid-carrying region of the pressure chamber comprises an inlet and an outlet by means of which the apparatus can be interposed in a liquid-carrying conduit of a liquid-carrying system.

13. Liquid-carrying system comprising an apparatus according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will be detailed subsequently referring to the appended drawings, in which:

(2) FIG. 1 is a schematic sectional view of an embodiment of an inventive apparatus,

(3) FIG. 2 is a schematic view of an inventive apparatus interposed in a liquid-carrying system,

(4) FIG. 3 is a schematic view of a further embodiment of an inventive apparatus and

(5) FIG. 4 is a schematic sectional view of a further embodiment of an inventive apparatus interposed in a liquid-carrying system.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows an inventive apparatus 100. The apparatus 100 comprises a pressure chamber 101 and a micropump 102 in fluid connection with the pressure chamber 101.

(7) The pressure chamber 101 has a gas-carrying region 103 and a liquid-carrying region 104.

(8) The micropump 102 is configured to generate a pneumatic pressure within the gas-carrying region 103 that is lower than the fluid pressure of a liquid 105 flowing through the liquid-carrying region 104. Gas and/or gas mixture can be dissolved in the liquid 105.

(9) A gas-permeable and liquid-impermeable separating element 106 is disposed within the pressure chamber 101, which separates the gas-carrying region 103 and the liquid-carrying region 104 from one another at least in sections.

(10) The micropump 102 is disposed on the pressure chamber 101.

(11) The embodiment of the inventive apparatus 100 shown in FIG. 1 is suitable to at least partly remove gas and/or gas mixture and/or parts of a gas mixture dissolved in a liquid 105 from this liquid 105. This process is also referred to as degassing the liquid 105. Accordingly, such apparatuses 100 can also be referred to as degassers.

(12) The inventive apparatus 100 can be interposed in a liquid-carrying system whose liquid 105 is to be degassed. For that, the pressure chamber 101 can comprise a liquid inlet 107 and a liquid outlet 108. Then, the liquid 105 to be degassed flows in the direction indicated by arrows from the inlet 107 to the outlet 108.

(13) The region within the pressure chamber 101 through which the liquid to be degassed 105 flows is also referred to as liquid-carrying region 104 of the pressure chamber 101.

(14) A separating element 106 separates the liquid-carrying region 104 of the pressure chamber 101 from the remaining interior of the pressure chamber 101. Here, the separating element 106 is configured as a gas-permeable and liquid permeable membrane 106. In the embodiment shown in FIG. 1, the membrane 106 is folded in order to obtain a large surface. It is also possible that the membrane is not folded.

(15) Gas, in particular ambient air, is in the just-mentioned remaining region in the interior of the pressure chamber 101. Thus, this region of the pressure chamber 101 is also referred to as gas-carrying region 103.

(16) A micropump 102 is disposed on the outside of the pressure chamber 101. The micropump 102 can also be disposed on the inside of the pressure chamber 101. The micropump 102 comprises a gas inlet 109 and a gas outlet 110. The gas inlet 109 is fluidically connected to the gas-carrying region 103 of the pressure chamber 101. The gas outlet 110 is fluidically connected to the environment surrounding the pressure chamber 101.

(17) The micropump 102 is configured to suck the gas in the gas-carrying region 103 through the gas inlet 109 and to supply the same to the environment through the gas outlet 110. Since the pressure chamber is configured mostly in a pressure-tight manner, a negative pressure is formed in the pressure chamber 101 as compared to the ambient pressure.

(18) The liquid to be degassed 105 is introduced into the pressure chamber 101 approximately at ambient pressure (or e.g., at a fluid pressure which is approximately 5%-10% above the atmospheric pressure). Depending on the ambient pressure (or the fluid pressure) as well as on the ambient temperature, a certain amount of gas or gasses is dissolved in the liquid to be degassed 105. In the environment, the gas or gas mixture dissolved in the liquid 105 has a specific partial pressure.

(19) According to Henry's Law, the partial pressure of a gas above a liquid is directly proportional to the concentration of the gas in the liquid. This means the higher the ambient pressure the higher the partial pressure of the gas and, hence with given dissolubility, the concentration of the gas, i.e., the more gas can be absorbed by the liquid. On the other hand, with decreasing partial pressure of the gas or gas mixture, the volatility of the gas in the liquid increases (or the concentration of the gas dissolved in the liquid decreases).

(20) This effect is used by the inventive apparatus 100. By pumping off the gas within the gas-carrying region 103 by means of the micropump 102, a pressure develops in the gas-carrying region 103 that is lower than the partial pressure of the gas (or gas component) dissolved in the liquid to be degassed 105, which is to be removed. In the gas-carrying region 103 of the pressure chamber 101 a negative pressure develops compared to the partial pressure of the gas dissolved in the liquid 105.

(21) A pressure gradient develops between the gas-carrying region 103 and the liquid-carrying region 104, which is directed from the region of the higher pressure (liquid-carrying region 104) to the region of lower pressure (gas-carrying region 103).

(22) Since the different gas pressures try to compensate each other, the gas dissolved in the liquid to be degassed 105 tries to flow into the gas-carrying region 103 of the pressure chamber 101.

(23) As mentioned above, the separating element 100 is gas-permeable. Thus, the gas dissolved in the liquid to be degassed 105 can diffuse through this separating element 106 from the liquid-carrying region 104 into the gas-carrying region 103.

(24) Since the separating element 106 is also liquid-impermeable, the liquid to be degassed 105 itself remains in the liquid-carrying region 104 of the pressure chamber 101. As a result, significantly less gas is dissolved in the liquid 105 flowing out of the pressure chamber 101 through the liquid outlet 108 than in the liquid 105 flowing into the pressure chamber 101 through the liquid inlet 107.

(25) The micropump 102 is configured to generate a negative pressure of −30 kPa to −55 kPa with respect to the atmospheric pressure in the gas-carrying region 103. This negative pressure is particularly well suited to withdraw ambient air from the liquid to be degassed 105, which is dissolved therein.

(26) The physical principle on which degassing the liquid by means of the inventive apparatus 100 is based will be discussed in more detail schematically with reference to FIG. 2.

(27) FIG. 2 shows a liquid-carrying system 200 into which an inventive apparatus 100 for degassing a liquid 105 is interposed.

(28) The inventive apparatus 100 comprises a pressure chamber 101. A micropump 102 is disposed on the pressure chamber 101. The micropump 102 is fluidically connected to a gas-carrying region 103 of the pressure chamber 101.

(29) Additionally, the pressure chamber 101 comprises a liquid-carrying region 104. In this case, the pressure chamber 101 comprises a tube forming the liquid-carrying region 104.

(30) Additionally, the tube comprises, at least in sections, a gas-permeable and liquid-impermeable material. Advantageously, the wall of the tube is made of such a material that the wall of the tube forms a gas-permeable and liquid-impermeable separating element 106. It is also possible that a non-wetting gas-permeable and liquid-impermeable membrane is incorporated in the tube wall.

(31) Additionally, the liquid-carrying system 200 comprises a delivery pump 202 delivering a liquid to be degassed 105 from a reservoir 203 through the inventive apparatus 100 to a container 204. In flow direction before and after the inventive apparatus 100, oxygen measurement devices 205a, 205b are each disposed in the fluid conduit.

(32) Within the reservoir 203 is water 105 in which a given amount of gas (e.g., air with 21% oxygen) is dissolved, which is characteristic for the prevailing atmospheric pressure. The delivery pump 202 pumps the liquid 105 out of the reservoir 203 through the vacuum chamber 101 where the water 105 is degassed.

(33) Since no sensors for measuring nitrogen dissolved in water are available, the amount of air dissolved in the water is derived by measuring the oxygen concentration. The two 02 sensors 205a, 205b measure the oxygen content of water 105 from which the amount of dissolved air is deduced.

(34) The degassing effect is based on the fact that the liquid 105 in the liquid-carrying region 104 (e.g., porous tube) is guided through a chamber 101 which is subject to negative pressure (briefly called vacuum chamber or pressure chamber). The dissolved gas adapts itself to the other physical conditions (negative pressure) and diffuses through the separating element (e.g., the tube walls) 106 into the chamber 101. The micropump 102 generates the negative pressure needed for that and maintains the same during operation.

(35) Advantageously, the delivery pump 202 is positioned behind the inventive apparatus (degasser) 100 in flow direction. If the delivery pump 202 is in front of the vacuum chamber 101, a positive pressure is generated in the liquid cycle such that the inventive apparatus (degasser) 100 cannot operate optimally and air bubbles can occur behind the vacuum chamber 101.

(36) FIG. 3 shows a further embodiment of the inventive apparatus 100. In this embodiment, the pressure chamber 101 comprises a liquid inlet 107 and a liquid outlet 108. A tube conduit 301 is disposed between the inlet 107 and the outlet 108. The tube conduit 301 forms the liquid-carrying region 104 within the pressure chamber 101.

(37) The walls of the tube 301 can comprise a gas-permeable and liquid-impermeable material, at least in sections. This can, for example, be porous tube. In that way, the tube walls form a separating element 106, at least at these gas-permeable and liquid-impermeable sections. When the tube 301 shows a gas-permeable and liquid-impermeable characteristic along its entire length extending within the pressure chamber 101, the tube 301 forms the liquid-carrying region 104 within the pressure chamber 101 and simultaneously the tube walls form the separating element 106 across the entire length of the tube 301 by which the gas dissolved in the liquid to be degassed 105 can diffuse into the gas-carrying region 103 of the pressure chamber 101 in order to degas the liquid 105.

(38) For obtaining a high degassing rate, it is advantageous to place as much as possible of the tube 301 within the pressure chamber 101. Thus, as indicated schematically in FIG. 3, the tube 301 is wound up in a spiral or helical shape.

(39) Compared to the above described embodiments, the embodiment shown in FIG. 3 additionally comprises an optional pressure sensor sensor 302. The pressure sensor 302 is fluidically coupled to the pressure chamber 101, i.e. gas exchange between the pressure sensor system 302 and the pressure chamber 101 is possible in order to measure the air pressure within the pressure chamber 101. More specifically, the pressure sensor 302 is fluidically coupled to the gas-carrying portion 103 of the pressure chamber 101.

(40) The apparatus 101 additionally comprises a control 303. The control 303 is connected to the pressure sensor 302 and to the micropump 102 via respective signal lines 304a, 304b. The control 303 is configured to control the micropump 102 in dependence on a signal of the pressure sensor 302 such that the micropump 102 is switched on when the pressure within the gas-carrying region 103 of the pressure chamber 101 rises above a threshold.

(41) For example, the degassing rate between a negative pressure prevailing in a pressure chamber 101 of −30 kPa to −55 kPa (with respect to atmospheric pressure) is very good. Accordingly, the control 303 could store, for example, the greater value, i.e., −30 kPa as a threshold.

(42) When the control 303 detects, by means of the pressure sensor 302, during operation that the negative pressure drop in the pressure chamber 101 has become too large, i.e., that the pressure within the pressure chamber 101 rises above the threshold of −30 kPa and beyond, the control 303 controls the micropump 102 such that the micropump 102 starts pumping again and discharges gas from the gas-carrying region 103 again. Thereby, the negative pressure in the pressure chamber 101 increases, i.e., the pressure within the pressure chamber 101 falls again to a value below the threshold, i.e., less than −30 kPa.

(43) Thus, the micropump 102 can be operated in a clocked manner or can be controlled as needed, for example to save energy.

(44) A further embodiment is shown in FIG. 4. This embodiment is similar to the embodiment described above with reference to FIG. 2. Additionally, an optional control 303 and an optional pressure sensor 302 are provided.

(45) Here, the apparatus 100 is interposed in a liquid-carrying system 200. The liquid to be degassed 105 is delivered through the apparatus 100 by means of a delivery pump 202. The delivery pump 202 itself can be configured as a micropump.

(46) However, it would also be possible that the micropump 102 fluidically connected to the gas-carrying region 103 of the pressure chamber 101 delivers the liquid to be degassed 105. In that case, the micropump 102 would comprise, apart from the shown gas ducts, i.e. gas inlet 109 and gas outlet 110, additional (not shown) liquid ducts, i.e. a liquid inlet and a liquid outlet that are interposed serially into the liquid-carrying conduit 401. In that way, the micropump 102 could deliver the liquid to be degassed 105 through the liquid-carrying region 104.

(47) Depending on which pump delivers the liquid 105, i.e. either the micropump 102 or the separate delivery pump 202, the respective liquid-delivering pump 102, 202 is connected to the control 303. Additionally, the pressure sensor 302 is connected to the control 303.

(48) The control 303 is configured to control the liquid-delivering pump 102, 202 in dependence on a signal of the pressure sensor 302 such that the delivery rate of the liquid-delivering pump 102, 202 is increased until so much gas is outgassed from the liquid 105 that the pressure within the gas-carrying region 103 reaches a threshold.

(49) Alternatively or additionally, the control 303 is configured to control the liquid-delivering pump 102, 202 in dependence on a signal of the pressure sensor 302 such that at a pressure exceeding a threshold within the gas-carrying region 103, the delivery rate of the liquid-delivering pump 102, 202 is lowered in order to decrease the degassing rate of the liquid 105.

(50) As already mentioned above, degassing the liquid 105 has the effect that gas diffusing from the liquid-carrying region 104 into the gas-carrying region 103 effects an increase of the pressure within the gas-carrying region 103, i.e. the negative pressure is reduced.

(51) As long as the pressure sensor 302 determines that the negative pressure in the gas-carrying region 103 of the pressure chamber 101 does not fall below a predefined threshold, e.g. −30 kPa (i.e. absolute pressure does not rise above the predefined threshold), the delivery rate of the liquid-delivering pump 102, 202 can be increased further.

(52) If, however, the pressure sensor 302 determines that the negative pressure in the gas-carrying region 103 of the pressure chamber 101 has fallen below the threshold, e.g. −30 kPa (i.e. absolute pressure increases, negative pressure decreases), this indicates that more gas diffuses into the gas-carrying region 103 as the micropump 102 can evacuate out of the pressure chamber 101. Thus, the control 303 controls the delivery pump 102, 202 such that the same reduces its delivery rate. By a reduced delivery rate, the liquid 105 flows slower through the pressure chamber 101 and the micropump 102 has more time to evacuate the diffused gas out of the pressure chamber 101. Thereby, the negative pressure in the pressure chamber 101 can be maintained sufficiently high.

(53) For increasing the degassing rate further, the apparatus 100 can comprise a temperature regulation apparatus 402. The temperature regulation apparatus 402 is configured to lower the temperature within the gas-carrying region 103 of the pressure chamber 101 by means of a cooling element 403 and/or to increase the temperature of the liquid to be degassed 105 in the liquid-carrying region 104 by means of a heating element 404.

(54) Generally, the efficiency of the inventive apparatus 100 can be influenced by means of several parameters. These are, for example, the maximum amount of dissolved gas in dependence on temperature and pressure, diffusion times of gases in liquids and through porous media (such as a tube 301 with gas-permeable and liquid-impermeable material).

(55) Together with technical parameters of the inventive apparatus 100 and specifications of specific target applications, requirements for the dimension of the liquid-carrying region (e.g. tube) 104 and the pressure chamber 101 result.

(56) Technical Parameters:

(57) Delivery rate delivery pump 102, 202 Existing diameters of the porous tube 104, 301 Possible negative pressure by micropump 102 up to −55 kPa Pressure drop due to tube length and inner diameter Retention time in the vacuum chamber 101 (combination of delivery rate and tube length)
Specification Application Example: Maximum flow rate where the degassing is to function: e.g. 100 μl/min. This delivery rate is advantageous since both in portable analysis systems (e.g. Lab-on-chip) as well as in portable medication dosage systems (in particular patch pumps), the maximum delivery rates are below this value With the inventive apparatus 100, the liquid 105 is to be transferred from the potentially saturated state (100% dissolved air) into a state of low saturation so that in portable microdosage systems, the liquid can no longer outgas due to variations of pressure or temperature, since bubbles can have a negative effect on dosage accuracy or sensor function. Thus, degassing of at most 30% by means of the inventive apparatus 100 can be achieved, i.e. the liquid 105 has a saturation of a maximum of 70% after passing through the inventive apparatus 100.

(58) This results in the following requirements for tube 301 and pressure chamber 101: Tube inner diameter 0.61 mm Tube length see table 1

(59) TABLE-US-00001 TABLE 1 Flow rate Tube length Tube volume Pressure drop [μl/min] [m] [mm.sup.3] [kPa] 50 0.14 58 0.03 100 0.27 116 0.13 150 0.41 174 0.30 200 0.54 232 0.54

(60) The retention time in the vacuum chamber 101 is approximately 48 seconds for each of these tube lengths, which could be a suitable time for many applications at the maximum possible degassing (55%). For higher delivery rates, the degassing rate decreases.

(61) A further boundary condition is that the vacuum chamber 101 is designed to be large enough so that the pressure in the chamber 101 does not increase too strongly at a high degassing rate or when a gas bubble is sucked out. Since the porous tube 301 can be wound up to an (spiral or helical shape) spiral, in order to not be bent, the vacuum chamber 101 can for example be shaped as a cylinder. In dependence on the tube length, chamber volumes which are a plurality of the tube volume result automatically.

(62) In the following, the invention will be summarized in other words.

(63) The present invention describes an apparatus 100 by which bubbles can be withdrawn from liquids 105 and also the dissolved gas can be partly withdrawn so that it is ensured that no gas bubble reaches the outlet 108 of the apparatus 100 and also no liquid saturated with gas reaches the outlet 101 and in that way no gas can outgas.

(64) Thereby, systems can be realized where gas bubbles are disadvantageous without needing a vacuum pump or a vacuum port.

(65) This apparatus 100 can be realized in a very small manner, and thereby liquids without bubbles can be provided even in portable applications, e.g. portable analysis systems, lap onto the systems, sensor systems, handheld devices, etc.

(66) Technical fields of application can be, for example: All microfluidic systems transporting liquids where gases are dissolved or exist in the form of bubbles. Fluidic measurement technology Lab-on-Chip systems Industry plants needing gas-free liquids and whose dimensions have tubes in the millimeter range and delivery rates of few ml/min. Biotechnology and medical technology applications handling liquids in the microliter range.

(67) As an active element, the inventive apparatus 100 includes a micropump 102 having low power requirements, depending on the embodiment between 5 mW and a few hundred mW, such that degassing of the portable system is possible over a long time period with a battery.

(68) The invention integrates the micropump 102 building up the needed negative pressure for an active degasser into the degasser component. Thus, only electric power is needed as single supply. Thus, a large advantage is mobility. A further advantage is the low space requirement. Conventional degassers need a separate pump. A further advantage is the saving of energy. Due to leakage rates at ports and connecting tubes, external pumps normally show losses that involve additional energy expenditure.

(69) The degassing rate depends on the built-up negative pressure. In the field of microfluidic systems, the micropump 102 of the applicant is the only known micropump having a sufficiently high compression ratio for building up such a negative pressure.

(70) In practice, it is frequently not needed to completely degas the liquid 105. It should only be ensured that the liquid 105 is degassed to such an extent that no bubbles occur during operation at common temperature and pressure variations.

(71) It can be seen, for example in FIG. 1, that the gas-permeable and liquid-impermeable (e.g. non-wetting) membrane 106 is placed in a negative pressure chamber 101 where a micropump 102 is integrated in its shell. The needed negative pressure is thereby generated directly in a degasser component. A vacuum port can be omitted.

(72) The degasser 100 is interposed into a fluidic system 200 at a suitable position (see also FIG. 2). Delivery of the system 200 drives the liquid to be degassed 105 though the inlet 107 into the fluid duct 104 with the non-wetting membrane (or tube) 106. The micropump 102 builds up a negative pressure in the negative pressure chamber 101. By the pressure difference in the fluid duct 104 relative to the surrounding chamber 101 gas is sucked into the chamber 101 through the non-wetting membrane 106. This reduces the negative pressure in the chamber 101 which is compensated again by the pump 102.

(73) An optional pressure sensor 302 (see FIGS. 3 and 4) is not needed for normal operation. For energy-saving operation, the pressure sensor 302 can be used for regulating the micropump 102. The micropump 102 is only switched on when the pressure rises above a threshold (or the negative pressure falls below a threshold).

(74) Physically, a diffusion process is behind this degasser 100 which is driven by the pressure difference between the negative pressure chamber 101 and the ambient pressure outside the chamber 101. The amount of the gas dissolved in the liquid 105 depends on the ambient pressure and the composition of the partial pressures. In the negative pressure chamber 100, a lower pressure acts on the liquid 105 and the dissolved gasses, such that this difference is compensated by diffusion. Thus, the pressure difference limits both the maximum obtainable degassing of the liquid 105 as well as the degassing rate per unit of time.

(75) At the same time, the geometry and the permeability of the liquid-carrying region 104 with non-wetting membrane 106 influence the diffusion. From these influences, a degassing rate per unit of time results, such that the fluid speed and the fluid duct length have to be coordinated depending on the application.

(76) When configuring the micropump 102, it has to be considered whether a liquid saturated with gas 105 is to be degassed or whether also larger gas bubbles have to be sucked. When designing the negative pressure chamber 101, its size or volume plays a main part in the buffer effect of the chamber 101. If the degassing rate exceeds the delivery rate of the micropump 102, the pressure in the negative pressure chamber 100 increases, which results in a lower degassing rate. The pressure increase depends on the size of the negative pressure chamber 101. These factors have to be considered in the interaction of all components.

(77) In the following, some possible embodiments will be outlined in key words. Apparatus 100 consisting of fluid conduit 104, gas-permeable element 106 and pressure chamber 101 for reducing dissolved gases in the conduit 104 that is filled with liquid and through which liquid flows due to a micropump generating negative pressure 102. Apparatus 100 consisting of at least one fluid inlet 107 and fluid outlet 108, a fluid region 104 between fluid inlet 107 and fluid outlet 108 and a pressure chamber 101, wherein the pressure chamber 101 is at least partly separated from the fluid region 104 by a gas-permeable and liquid-impermeable separating element 106, wherein the pneumatic pressure in the pressure chamber 101 can be lowered below the fluid pressure by at least one micropump 102. Portable apparatus with power connection or battery operation Dissolved gases can also prevail as second phase (bubble) Micropump 102 can be integrated in the negative pressure chamber 101 or can be connected separately Gas-permeable element 106 can exist as tube, membrane, porous plate or in a folded manner Gas-permeable material can be hydrophobic, oleophobic, etc. Additional valve in the negative pressure chamber 101 or in the micropump conduit to prevent leakage rates or to supplement a regulation by ventilation or to introduce a “strip” gas or to introduce another defined gas composition Additional pressure sensor 302 in the negative pressure chamber 101 or micropump conduit. Connected therewith are different options of intelligent regulation for saving energy, micropump 102 is only operated when the negative pressure increases regulation of the delivery pump 102, 202 flow optimization Negative pressure remains the same.fwdarw.delivery rate can be increased Negative pressure increases despite maximum micropump power.fwdarw.lower delivery rate Continuous or demand-based operation of the micropump 102 Continuous or intermittent flow through the fluid conduit 104 Fluid delivery can also take place by the micropump 102 Additional temperature regulation in the negative pressure chamber 101 by heating or cooling elements 404, 403. Cooling the negative pressure chamber 101 and heating the fluid to be degassed 105, respectively, would increase the degassing rate. One or several fluid conduits in the negative pressure chamber 101 Bubble detection (e.g. capacitive, optical) in front of or in the negative pressure chamber 101 and pump regulation in dependence on bubble detection for switching on the micropump 102 or to lower the delivery rate in order to suck off the gas bubble. Detecting the degassing rate by an increase of the pressure in the negative pressure chamber 101 or by needed pump power for maintaining a pressure level, possibly with regulation that only completely degassed fluid 105 is transported further (=further miniaturization) Detection of fluid characteristics by degassing characteristics

(78) One feature of the inventive apparatus 100 is that the micropump 102 is disposed on the pressure chamber 101. Basically, the micropump (e.g. silicon micropump chip) 102 can be integrated in several ways into the inventive apparatus (degasser) 100.

(79) 1) Clamps

(80) The inlet and outlet 109, 110 of the micropump 102 are at the bottom of the micropump 102. The same can be fluidically connected to the degasser housing 101 in a tight manner in that the chip is clamped over one or several sealing elements. The sealing element can, for example be a soft plastic (e.g. silicon) having respective openings in the inlets and outlets 109, 110. This plastic can be formed, for example by hot stamping or injection molding. two O-rings onto which the pump chip 102 is clamped (when the pump chip is designed such that O-rings have enough space) The clamp element is, for example, a lid mounted on the pump chip 102 and pressing the chip 102 onto the sealing elements in a defined manner. This lid can be mounted to the degasser 101 by several screws or by a hinge and a snap lock It has to be considered in the sealing element that the sealing is gastight with respect to the obtainable negative pressure. For this, design rules have to be considered in the clamp structures. There are, for example, rules in the O-ring how the receivers have to be designed in order to ensure sufficient tightness at negative pressure. Here, when needed, respective structures can be realized both in the degasser housing 101 and in the pump chip 102 into which the silicon seals or the O-rings are inserted. 100 percent tightness is not needed. However, the existing leakage rates may not exceed the pump capacities for generating the negative pressure. Or, when no large energy budget is available during battery-operated application, the micropump 102 should not be continuously in operation for compensating the leakage rates and maintaining the negative pressure. However, passive check valves in the micropump 112 also have leakage rates, such that ambient air flows back into the negative pressure chamber 101 through the switched-off micropump 102. When the leakage rates are too large, the following might have to take place: A passive check valve has to be designed such that the leakage rate is minimum and possibly no residual gaps exist in the closing direction. For the seal, a “safety valve in reverse direction” is to be used (see, e.g. WO 2014/094879 A1). In these soft seals there is no residual gap.
2) Adhering or Joining with Joining Layer The pump chip 102 can be firmly connected directly with the degasser housing 100 by adhering welding bonding (e.g. anodic bond, eutectic bond)

(81) The arguments regarding tightness and leakage rates stated for clamping apply accordingly for joining.

(82) Advantage: adhering is mostly tighter than clamping, additionally less expensive and no clamp lid is needed.

(83) Regarding the product, adhering a micropump 102 with a flap valve with a small residual leakage rate is an advantageous solution, wherein the flap valves of the current Fraunhofer micropumps are already sufficiently good for degassers having approximately −50 kPa negative pressure and battery operation.

(84) With the inventive apparatus 100, a degasser is provided. Degassers 100 have the effect of withdrawing dissolved gasses out of liquids 105. So far, a vacuum port or a large vacuum pump has been needed for that. In the inventive apparatus 100, the needed negative pressure is built up by an integrated micropump 102. This ensures increased mobility and reduces the needed supply to a power terminal.

(85) The inventive apparatus 100 comprises a vacuum chamber 101 for degassing, into the lid of which a micropump 102, optionally a pressure sensor 302 and fluidic 104 and electric ports can be integrated. A porous gas-permeable tube 301 can be inserted inside the vacuum chamber 101. By means of the inventive apparatus 100, negative pressures of −55 kPa relative to atmospheric pressure (approximately half standard air pressure) can be built up, by which water can be degassed by almost 50%. This corresponds to approximately 85% of the theoretically possible degassing at this negative pressure.

(86) In the present disclosure, the following terms are used:

(87) Pressure Units
1 atmosphere=1000 mbar=1000 hPa=100 kPa
Degassing

(88) Gases dissolve in liquid. This means that gas does not exist as bubble, but that individual gas molecules are mixed inbetween liquid molecules. If gas molecules are removed from a liquid, this is called degassing.

(89) Dissolubility

(90) The dissolubility relates to the characteristic of a specific liquid of dissolving a specific gas. The higher the dissolubility, the more gas can be dissolved in the liquid. The dissolubility depends on the temperature.

(91) Partial Pressure

(92) The partial pressure relates to the partial pressure of an individual component in a gas mixture. The sum of all partial pressures is equal to the total pressure. The partial pressure corresponds to the pressure which the individual gas component would apply when the same is solely present in the respective volume.

(93) Additionally, the present invention can be realized in the following embodiments:

(94) A first embodiment is an apparatus (100) with a pressure chamber (101) and a micropump (102) in fluid connection with the pressure chamber (101), wherein the pressure chamber (101) comprises a gas-carrying region and a liquid-carrying region (104), wherein the micropump (102) is configured to generate a pneumatic pressure within the gas-carrying region that is lower than a fluid pressure of a liquid (105) flowing through the liquid-carrying region (104), and wherein a gas-permeable and liquid-impermeable separating element (106) separates the gas-carrying region and the liquid-carrying region (104) at least in sections, wherein the micropump (102) is disposed on the pressure chamber (101).

(95) According to a second embodiment with reference to the first embodiment, the micropump (102) can be mounted on the pressure chamber (101) by means of screw and/or clamp fixing.

(96) According to a third embodiment with reference to the first or second embodiment, the micropump (102) can be mounted on the pressure chamber (101) by means of joining means, in particular by means of adhesive or solder.

(97) According to a fourth embodiment with reference to one of the above embodiments, the micropump (102) can be configured to generate a negative pressure of −30 kPa up to −55 kPa with respect to atmospheric pressure in the gas-carrying region of the pressure chamber (101).

(98) According to a fifth embodiment with reference to one of the above embodiments, the separating element (106) can be a gas-permeable and liquid-impermeable membrane disposed between the gas-carrying region and the liquid-carrying region (104).

(99) According to a sixth embodiment with reference to one of the above embodiments, the liquid-carrying region (104) can be a tube conduit (301) running within the pressure chamber (101).

(100) According to a seventh embodiment with reference to the sixth embodiment, the tube conduit (301) can comprise, at least in sections, a material forming the gas-permeable and liquid-impermeable separating element (106).

(101) According the an eight embodiment with reference to one of the above embodiments, the apparatus (100) can further comprise a pressure sensor (302) fluidically coupled to the gas-carrying region (103) and a control (303) connected to the pressure sensor (302), wherein the control (303) is configured to control the micropump (102) in dependence on a signal of the pressure sensor (303) such that the micropump (102) is switched on when the pressure within the gas-carrying region (103) of the pressure chamber (101) rises above a threshold.

(102) According to a ninth embodiment with reference to one of the above embodiments, the apparatus (100) can comprise a liquid-delivering pump (102, 202), by means of which liquid (105) can be delivered through the liquid-carrying region (104), or wherein the micropump (102) is configured to deliver liquid (105) through the liquid-carrying region (104).

(103) According to a tenth embodiment with reference to the ninth embodiment, the apparatus (100) can comprise a pressure sensor (302) fluidically coupled to the gas-carrying region (103) and a control (303) connected to the pressure sensor (302) and the liquid-delivering pump (102, 202), wherein the control (303) is configured to control the liquid-delivering pump (102, 202) in dependence on a signal of the pressure sensor (302) such that the delivery rate of the liquid-delivering pump (102, 202) is increased until the pressure within the gas-carrying region (103) reaches a threshold and/or such that the delivery rate of the liquid-delivering pump (102, 202) is lowered at a pressure exceeding a threshold within the gas-carrying region (103).

(104) According to an eleventh embodiment with reference to one of the above embodiments, the apparatus (100) can comprise a temperature regulation apparatus (402) that is configured to cool the gas-carrying region (103) and/or to heat the liquid-carrying region (104).

(105) According to a twelfth embodiment with reference to one of the above embodiments, the apparatus (100) can comprise a valve fluidically coupled to the gas-carrying region (103) which is connected to a strip gas-carrying conduit in order to introduce a strip gas into the gas-carrying region (103) of the pressure chamber (101).

(106) According to a thirteenth embodiment with reference to one of the above embodiments, a gas bubble detection means can be provided within the pressure chamber (101) or in a flow direction of the liquid (105) in front of the pressure chamber (101), which is configured to detect a gas bubble in the liquid (105), and wherein the apparatus (100) further comprises a control (303) that is configured to switch on the micropump (102) in dependence on a detected gas bubble.

(107) According to a fourteenth embodiment with reference to one of the above embodiments, the liquid-carrying region (104) of the pressure chamber (101) can comprise an inlet (107) and an outlet (108) by means of which the apparatus (100) can be inserted in a liquid-carrying conduit (401) of a liquid-carrying system (200).

(108) Further embodiments provide a liquid-carrying system (200) with an apparatus (100) according to one of the above embodiments.

(109) While this invention has been described in terms of several advantageous embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.