A water-gas equilibrator for the determination of dissolved gases in water

Abstract

The present application relates to the technical field of dissolved gas measurement in water, and discloses a water-gas balancer for dissolved gas measurement in water, which comprises an inner tube, an air outlet on the upper end of the inner tube, a first opening on the lower end of the inner tube, an immersion section and an exposed section on the immersion section, a plurality of gas-liquid separation holes arranged in a circle on the upper part of the immersion section, an air inlet tube, the exhaust end of the air inlet tube being sealed and penetrating the tube wall of the inner tube and being located in the immersion section below the gas-liquid separation holes, an outer tube, the outer tube being sleeved on the outer periphery of the immersion section, the upper end of the outer tube being sealed and connected with the tube wall of the inner tube, the lower end of the outer tube having a second opening, and a gas pump, the outlet of the gas pump being communicated with the air inlet end of the air inlet tube, and the inlet of the gas pump being communicated with the air outlet. The water-gas balancer for dissolved gas measurement in water can reduce power consumption and improve the speed of water-gas balance.

Description

Technical Field

[0001] This invention relates to the field of dissolved gas measurement technology in water, and in particular to a water-gas balancer for measuring dissolved gases in water. Background Technology

[0002] A water-air balancer is a necessary means to detect the concentration of dissolved gases (such as carbon dioxide, methane, and nitrous oxide) in water samples by exchanging matter between flowing water samples and gases. Current water-air balancers, such as the one disclosed in Chinese patent CN222028234U for seawater measurement, use a water pump to drive the water sample to contact with air for mass exchange. As the water sample continuously flows through the container, it carries away air from the top of the container, causing a continuous drop in the internal pressure of the balancer. To maintain a normal operating environment, clean air needs to be continuously added, thus prolonging the water-air balance time and affecting the speed of water-air balance. Furthermore, for water pumps delivering water samples and air pumps delivering air, under the same volumetric flow rate and normal pressure conditions, the power consumption of a water pump is significantly greater than that of an air pump. Summary of the Invention

[0003] The purpose of this invention is to provide a water-gas balancer for measuring dissolved gases in water, which can reduce power consumption and increase the speed of water-gas balancing.

[0004] To achieve the above objectives, the present invention provides a water-gas balancer for measuring dissolved gases in water, comprising: The inner tube has an air outlet at its upper end and a first opening at its lower end. The inner tube includes an immersion section and an exposed section located on the immersion section. The upper part of the immersion section has a plurality of gas-liquid separation holes arranged circumferentially. An air inlet pipe, the exhaust end of which is sealed through the wall of the inner pipe and located in the immersion section below the gas-liquid separation hole; An outer tube, spaced apart and fitted around the periphery of the immersion section, has its upper end sealed to the wall of the inner tube, and its lower end having a second opening; and An air pump, the outlet of which is connected to the air inlet of the air inlet pipe, and the inlet of the air pump is connected to the air outlet.

[0005] In some embodiments, both the inner tube and the outer tube are straight tubes, and the axis of the inner tube coincides with the axis of the outer tube.

[0006] In some embodiments, the ratio of the inner diameter of the outer tube to the outer diameter of the inner tube is 1.3-2.5.

[0007] In some embodiments, the water-air balancer further includes an aeration head, which is installed at the exhaust end of the air inlet pipe.

[0008] In some embodiments, the aeration head has a plurality of air holes with a diameter of 10-20 μm.

[0009] In some embodiments, the inner wall of the immersion section has spiral-shaped flow-guiding protrusions.

[0010] In some embodiments, the height of the guide protrusion is 1%-5% of the inner diameter of the immersion section.

[0011] In some embodiments, the lower end of the flow guiding protrusion is flush with the lower end of the immersion section, and the upper end of the flow guiding protrusion is spaced apart from the gas-liquid separation hole.

[0012] In some embodiments, the lower end of the inner tube extends beyond the lower end of the outer tube.

[0013] In some embodiments, the water-gas balancer further includes a gas detector, the inlet of which is connected to the gas outlet, and the outlet of which is connected to the inlet of the gas pump.

[0014] This invention provides a water-gas balancer for measuring dissolved gases in water, which has the following advantages compared with the prior art: By placing the submerged section below the water surface, an air pump introduces gas into the submerged section through the air inlet pipe. The rising air bubbles then carry the water sample upwards. The water sample passes through the gas-liquid separation hole and exits from the second opening of the outer tube, while the gas enters the upper end of the inner tube and exits from the air outlet, then enters the air pump inlet for circulation. This allows the air concentration to approach the dissolved gas concentration in the water sample, increasing the speed of water-gas equilibrium. Furthermore, the air pump circulates air to achieve mass exchange between the water sample and the gas, significantly reducing power consumption compared to using a water pump to transport the water sample for mass exchange. Attached Figure Description

[0015] Figure 1 This is a structural diagram of a water-gas balancer for measuring dissolved gases in water, provided in an embodiment of the present invention.

[0016] Figure 2 The diagram shows the structure of the inner and outer tubes of the water-gas balancer for measuring dissolved gases in water, provided in an embodiment of the present invention, with flow-guiding protrusions.

[0017] In the diagram: 100, water-air balancer; 1, inner pipe; 2, air inlet pipe; 3, outer pipe; 4, air pump; 1a, air outlet; 1b, first opening; 11, immersion section; 11a, gas-liquid separation hole; 111, guide protrusion; 12, exposed section; 3, outer pipe; 3a, second opening; 4, air pump; 5, aeration head; 6, gas detector. Detailed Implementation

[0018] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0019] It should be understood that in the description of this application, the terms "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. That is, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, unless otherwise stated, "a plurality of" means two or more.

[0020] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0021] like Figure 1 As shown, the water-gas balancer 100 for measuring dissolved gases in water according to an embodiment of the present invention includes an inner tube 1, an air inlet tube 2, an outer tube 3, and an air pump 4.

[0022] The inner tube 1 has an outlet 1a at its upper end and a first opening 1b at its lower end. The inner tube 1 includes an immersion section 11 and an exposed section 12 located on the immersion section 11. The upper part of the immersion section 11 has a plurality of circumferentially arranged gas-liquid separation holes 11a. The gas-liquid separation holes 11a are used to separate the gas from the water sample during the upward flow of the gas-water mixture.

[0023] The exhaust end of the intake pipe 2 is sealed through the wall of the inner pipe 1 and is located in the submerged section 11 below the gas-liquid separation hole 11a. The intake pipe 2 is used to introduce circulating gas into the inner pipe 1.

[0024] The outer tube 3 is spaced around the periphery of the immersion section 11. The upper end of the outer tube 3 is sealed to the wall of the inner tube 1, and the lower end of the outer tube 3 has a second opening 3a. The annular space between the outer tube 3 and the inner tube 1 forms an annular channel.

[0025] The outlet of air pump 4 is connected to the inlet end of air inlet pipe 2, and the inlet of air pump 4 is connected to the outlet 1a. In this way, a closed gas circulation loop is formed.

[0026] During operation, the immersion section 11 is placed below the water surface, at which point the cavity inside the immersion section 11 and the annular channel between the immersion section 11 and the outer tube 3 are filled with water sample.

[0027] The air pump 4 is activated, introducing gas into the submerged section 11 through the air inlet pipe 2, forming a large number of rising bubbles in the water sample within the submerged section 11. Since the density of the bubbles is much lower than that of the water sample, the bubbles carry the surrounding water sample upwards as they rise, forming a gas-water mixed upward flow. This gas-water mixed upward flow moves upwards through the interior of the submerged section 11. When the gas-water mixed upward flow reaches the area of ​​the gas-liquid separation hole 11a in the submerged section 11, the gas, due to its lower density, continues to rise into the exposed section 12, eventually exiting from the air outlet 1a and entering the inlet of the air pump 4 for circulation, achieving material exchange between the water sample and the gas, allowing the air concentration to approach the dissolved gas concentration in the water sample; while the water sample enters the annular channel between the inner tube 1 and the outer tube 3 through the gas-liquid separation hole 11a. Because the lower end of the outer tube 3 has a second opening 3a, the water sample entering the annular channel flows downwards under gravity, exiting from the second opening 3a, while simultaneously drawing in fresh water sample from the first opening 1b at the lower end of the inner tube 1, thus forming a stable water sample circulation.

[0028] During the above process, the circulating gas and the continuously updated water sample come into full contact in the gas-liquid mixed upflow, resulting in rapid gas-liquid substance exchange. Components in the gas, such as carbon dioxide, methane, or nitrous oxide, gradually tend to reach equilibrium with the dissolved gas concentration in the water sample. The gas after equilibrium is returned to the gas pump 4 through the gas outlet 1a for the next cycle or for detection and analysis.

[0029] Based on the above structural design, the water sample circulation is driven by the air lift principle, eliminating the need for an external water pump, which significantly reduces power consumption. At the same time, it avoids the problem of air pressure drop in the balancer caused by water pumping in the prior art, and improves the speed of water-air balance.

[0030] In some embodiments, both the inner tube 1 and the outer tube 3 are straight tubes, and the axis of the inner tube 1 and the axis of the outer tube 3 coincide. This ensures that the width of the annular channel between the inner tube 1 and the outer tube 3 is uniform, which is beneficial for the stable downstream flow of water samples.

[0031] In some embodiments, the ratio of the inner diameter of the outer tube 3 to the outer diameter of the inner tube 1 is 1.3-2.5. If the ratio is less than 1.3, the width of the annular channel is too narrow, the resistance to water flow is high, and the replenishment rate of fresh water sample is low; if it is greater than 2.5, the annular channel is too wide, resulting in a large overall structural space occupation, which is not conducive to carrying.

[0032] In some embodiments, the water-air balancer 100 further includes an aeration head 5, which is installed at the exhaust end of the air inlet pipe 2. Thus, the aeration head 5 can further increase the contact area between the air and the water sample.

[0033] In some embodiments, the aeration head 5 has multiple pores with a diameter of 10-20 μm. These pores generate smaller bubbles, increasing the contact surface area between air and water, thereby accelerating gas exchange and shortening the equilibrium time. If the pore diameter is less than 10 μm, manufacturing becomes difficult and clogging is likely; if it is greater than 20 μm, the bubbles are larger, the contact surface area decreases, and the exchange rate drops.

[0034] like Figure 2 As shown, in some embodiments, the inner wall of the immersion section 11 has spiral-shaped flow-guiding protrusions 111. In this way, the flow-guiding protrusions 111 can enhance the residence time and disturbance effect of bubbles in the inner tube 1.

[0035] In some embodiments, the height of the guide protrusion 111 is 1%-5% of the inner diameter of the immersion section 11. The guide protrusion 111 can generate rotational motion in the rising gas-water mixture, which on the one hand extends the movement path of the bubbles in the water sample, and on the other hand increases the turbulence of the water sample, thereby promoting gas-water interface disturbance and improving mass transfer efficiency.

[0036] In some embodiments, the lower end of the guide protrusion 111 is flush with the lower end of the immersion section 11, and the upper end of the guide protrusion 111 is spaced apart from the gas-liquid separation hole 11a. This is to avoid interfering with the gas-liquid separation process of the gas-water mixture at the gas-liquid separation hole 11a.

[0037] In some embodiments, the lower end of the inner tube 1 extends beyond the lower end of the outer tube 3. In this way, the water sample flowing out from the annular channel will not directly interfere with the intake of fresh water sample at the lower end of the inner tube, while also facilitating the formation of a natural water flow field around the water-air balancer 100, preventing the exchanged water sample from being immediately re-inhaled.

[0038] In some embodiments, the water-gas balancer 100 further includes a gas detector 6, the inlet of which is connected to the outlet 1a, and the outlet of which is connected to the inlet of the gas pump 4. Thus, continuous online detection is achieved through the gas detector 6. Specifically, the gas detector 6 can be a non-dispersive infrared absorption spectrometer (for measuring carbon dioxide), a gas chromatograph, or a tunable diode laser absorption spectrometer (for measuring methane and nitrous oxide), etc. The balanced gas first flows through the gas detector 6 for concentration measurement, and then returns to the inner tube 1 via the gas pump 4 for circulation. This closed-loop setup can monitor changes in the concentration of the balanced gas in real time until equilibrium is determined and dissolved gas concentration data is output.

[0039] In some embodiments, the inner tube 1 and outer tube 3 may be made of corrosion-resistant plexiglass, stainless steel, or polytetrafluoroethylene. The air pump 4 should be a low-flow, low-power miniature diaphragm pump to meet the long-term operational needs of power-constrained platforms such as buoys. To prevent moisture from entering the detector, a cold trap or drying tube may be added between the air outlet 1a and the gas detector 6.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A water-gas balancer for measuring dissolved gases in water, characterized in that, include: The inner tube has an air outlet at its upper end and a first opening at its lower end. The inner tube includes an immersion section and an exposed section located on the immersion section. The upper part of the immersion section has a plurality of gas-liquid separation holes arranged circumferentially. An air inlet pipe, the exhaust end of which is sealed through the wall of the inner pipe and located in the immersion section below the gas-liquid separation hole; An outer tube, spaced apart and fitted around the periphery of the immersion section, has its upper end sealed to the wall of the inner tube, and its lower end having a second opening; and An air pump, the outlet of which is connected to the air inlet of the air inlet pipe, and the inlet of the air pump is connected to the air outlet.

2. The water-gas balancer for measuring dissolved gases in water according to claim 1, characterized in that, Both the inner tube and the outer tube are straight tubes, and the axis of the inner tube coincides with the axis of the outer tube.

3. The water-gas balancer for measuring dissolved gases in water according to claim 2, characterized in that, The ratio of the inner diameter of the outer tube to the outer diameter of the inner tube is 1.3-2.

5.

4. The water-gas balancer for measuring dissolved gases in water according to claim 1, characterized in that, The water-air balancer also includes an aeration head, which is installed at the exhaust end of the air inlet pipe.

5. The water-gas balancer for measuring dissolved gases in water according to claim 4, characterized in that, The aeration head has multiple air holes with a diameter of 10-20 μm.

6. The water-gas balancer for measuring dissolved gases in water according to claim 1, characterized in that, The inner wall of the immersion section has spiral-shaped flow-guiding protrusions.

7. The water-gas balancer for measuring dissolved gases in water according to claim 6, characterized in that, The height of the guide protrusion is 1%-5% of the inner diameter of the immersion section.

8. The water-gas balancer for measuring dissolved gases in water according to claim 6, characterized in that, The lower end of the flow guide protrusion is flush with the lower end of the immersion section, and the upper end of the flow guide protrusion is spaced apart from the gas-liquid separation hole.

9. The water-gas balancer for measuring dissolved gases in water according to claim 1, characterized in that, The lower end of the inner tube extends beyond the lower end of the outer tube.

10. The water-gas balancer for measuring dissolved gases in water according to claim 1, characterized in that, The water-gas balancer also includes a gas detector, the inlet of which is connected to the gas outlet, and the outlet of which is connected to the inlet of the gas pump.

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