Dissolved hydrogen concentration detector

Abstract

The invention relates to the technical field of gas analysis and detection, in particular to a dissolved hydrogen concentration detector which comprises a sample bottle, a sampling pipe, a peristaltic pump, a balance cavity, an air bag, a heat exchanger, a semiconductor cold sheet, an automatic drainer, a thermal conductivity sensor, a laminar flow cavity, an exhaust two-position three-way valve, a circulating pipeline, an air inlet two-position three-way valve, an air pump and a disperser. The device adopts a thermal conductivity detector identical to a headspace gas chromatography method, adopts circulating headspace sampling similar to headspace sampling, does not adopt continuous carrier gas as circulating gas, does not have a dilution process, and is lower in detection limit; meanwhile, as a gas-liquid balance process is completed between the circulating gas and the sample every time, the balance of hydrogen dissolved in the sample and headspace gas can be ensured to the maximum extent, the measurement is more accurate, and the whole equipment is small in size, light in weight, low in power, capable of being powered by a No.5 battery, capable of being used as a handheld portable instrument, simple to operate and convenient to use. The method is very suitable for hydrogen water concentration detection in various environments.

Description

Technical Field

[0001] The present invention relates to the technical field of gas analysis and detection, and in particular to a dissolved hydrogen concentration detector. Background Art

[0002] Hydrogen-rich water is increasingly being used for a wide range of applications, including drinking, bathing, agricultural irrigation, and aquaculture. Existing methods for testing dissolved hydrogen concentration primarily include ORP (Optical Reaction Processing) (OPR), reagent titration, and headspace gas chromatography. Of these methods, the ORP method is only applicable to pure water systems. The reagent titration method is expensive and cumbersome to operate, while the headspace gas chromatography method is technically complex and requires high equipment costs. This makes it unsuitable for on-site, immediate testing, such as hydrogen water irrigation and hydrogen-rich water beverage production. In particular, for hydrogen water irrigation, due to the complex water quality, ORP and titration methods cannot accurately monitor hydrogen concentrations.

[0003] In view of this, the present invention provides a dissolved hydrogen concentration detector, which uses a thermal conductivity detector exactly the same as that used in headspace gas chromatography and adopts cyclic headspace sampling, which is similar to headspace sampling. Since the circulating gas does not use a continuous carrier gas, there is no dilution process and the detection limit is lower. At the same time, since the circulating gas completes a gas-liquid equilibrium process with the sample each time it circulates, the balance between the dissolved hydrogen in the sample and the headspace gas can be guaranteed to the greatest extent, and the measurement is more accurate. The entire device is small in size, light in weight, and low in power. It can be powered by a No. 5 battery and can be used as a handheld portable instrument. It is simple to operate and is very suitable for hydrogen water concentration detection in various environments. Summary of the Invention

[0004] The object of the present invention is to provide a dissolved hydrogen concentration detector to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A dissolved hydrogen concentration detector, characterized in that it includes a sample bottle, a sampling tube, a peristaltic pump, a balancing chamber, an air bag, a heat exchanger, a semiconductor refrigeration sheet, an automatic drain, a thermal conductivity sensor, a laminar flow chamber, a two-position three-way exhaust valve, a circulation line, a two-position three-way intake valve, an air pump, and a disperser;

[0007] The peristaltic pump is located on the sampling tube, and its function is to inject the water sample to be tested in the sampling tube into the balance chamber through the sampling tube;

[0008] The balancing chamber is a hollow cylindrical chamber, and the disperser is located inside the balancing chamber; the air bag is sealed and connected to the top of the balancing chamber, and the top of the balancing chamber is connected to the disperser through a circulation pipeline. The circulation pipeline is sequentially installed with a heat exchanger, a laminar flow chamber, a two-position three-way exhaust valve, a two-position three-way intake valve, and an air pump from the top of the balancing chamber to the disperser; the function of the air pump is to transport the gas at the top of the balancing chamber through the heat exchanger, the laminar flow chamber, the two-position three-way exhaust valve, and the two-position three-way intake valve to the disperser in sequence, and the interfaces of the two-position three-way exhaust valve and the two-position three-way intake valve that are not connected to the circulation pipeline are connected to the atmosphere;

[0009] The heat exchanger is provided with an air inlet, an air outlet and a drain port. The semiconductor cooling plate is close to the heat exchanger and its function is to cool the gas passing through the heat exchanger through the semiconductor cooling plate. The automatic drain valve is provided with a water inlet and a drain port. The water inlet and the drain port of the automatic drain valve are connected to the water outlet of the heat exchanger and the top of the balance chamber respectively.

[0010] The thermal conductivity sensor is sealed and connected to the laminar flow cavity.

[0011] Furthermore, the disperser is a device with a microporous structure of 10nm-100μm on the surface of an organic membrane, an inorganic membrane, a metal sintered aeration head, etc., and its function is to disperse the gas passing through the disperser in the form of small bubbles in water;

[0012] Furthermore, the laminar flow cavity is provided with an air inlet, an air outlet, an air inlet dispersion cavity, an air outlet dispersion cavity, and several gas flow channels which are parallel to each other and have rectangular cross-sections. The gas flows in the gas flow channels with rectangular cross-sections, and the Reynolds number Re value is less than 2300, and more preferably, the Re value is less than 800.

[0013] Compared with the prior art, the beneficial effects of the present invention are: a dissolved hydrogen concentration detector, which adopts a thermal conductivity detector exactly the same as that of headspace gas chromatography, and adopts cyclic headspace sampling which is similar to headspace sampling. Since the circulating gas does not use a continuous carrier gas, there is no dilution process, and the detection limit is lower; at the same time, since the circulating gas completes a gas-liquid equilibrium process with the sample each time it circulates, the balance between the dissolved hydrogen in the sample and the headspace gas can be guaranteed to the greatest extent, and the measurement is more accurate. The entire device is small in size, light in weight, and low in power. It can be powered by a No. 5 battery and can be used as a handheld portable instrument. It is simple to operate and is very suitable for hydrogen water concentration detection in various environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an overall schematic diagram of the present invention.

[0015] Figure 2 It is a schematic diagram of the cross-sectional structure of the laminar flow cavity of the present invention.

[0016] Serial numbers in the figure: 1 is the sample bottle, 2 is the sampling tube, 3 is the peristaltic pump, 4 is the air bag, 5 is the heat exchanger, 501 is the air inlet of the heat exchanger, 502 is the air outlet of the heat exchanger, 503 is the drain outlet of the heat exchanger, 6 is the semiconductor refrigeration plate, 7 is the thermal conductivity sensor, 8 is the laminar flow chamber, 801 is the air inlet of the laminar flow chamber, 802 is the air outlet of the laminar flow chamber, 803 is the air inlet dispersion chamber, 804 is the air outlet dispersion chamber, 805 is the gas flow channel, 9 is the two-position three-way exhaust valve, 10 is the circulation pipeline, 11 is the two-position three-way intake valve, 12 is the air pump, 13 is the ceramic membrane tube, 14 is the automatic drainer, 1401 is the water inlet of the automatic drain valve, 1402 is the drain outlet of the automatic drain valve, and 15 is the balance chamber. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0019] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense. For example, it can be fixedly connected or set, or detachably connected or set, or connected or set as a whole. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to the specific circumstances. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly specified and limited.

[0020] See also Figure 1-2 As shown, an embodiment of a dissolved hydrogen concentration detector provided by the present invention is as follows:

[0021] Pour 20ml of sample containing dissolved hydrogen into the sample bottle 1, start the peristaltic pump 3 to inject 10ml of sample into the balancing chamber 15 with a volume of 20ml, and the internal pressure of the balancing chamber 15 gradually becomes higher than the atmospheric pressure, causing the airbag 4 to expand and the internal pressure of the balancing chamber 15 to decrease, so that the internal pressure of the balancing chamber 15 is maintained near the atmospheric pressure during the process of the peristaltic pump 3 injecting the sample, so that the flow rate of the peristaltic pump 3 remains stable. When the peristaltic pump 3 determines that the amount of sample injected into the balancing chamber 15 reaches 10ml based on the number of rotations, the peristaltic pump 3 is turned off; the air pump 12 is started to draw the gas in the upper part of the balancing chamber 15 into the circulation pipeline 10, and the gas enters the heat exchanger 5 through the heat exchanger inlet 501, close to the heat exchanger. The semiconductor refrigeration plate 6 of the device 5 cools the gas and reduces the humidity. The generated liquid condensed water enters the automatic drain 14 through the heat exchanger drain port 503 and the automatic drain valve inlet 1401. When the water volume in the automatic drain 14 reaches a certain value, it is discharged into the balance chamber 15 through the automatic drain valve drain port 1402. The gas cooled and dried by the heat exchanger 5 passes through the heat exchanger outlet 502 and enters the laminar flow chamber inlet 801 at a flow rate of 50 ml / min. It enters the laminar flow chamber 8 and is dispersed by the air inlet dispersion chamber 803. It enters 11 parallel gas flow channels 805 with a depth of 10 mm and a width of 2 mm. The gas volume flow rate in each channel is 0.076 ml / s, and the flow rate is 3.8 x 10 -3 m / s. According to the Reynolds number Re = ρvd / μ, its value is 422, indicating a laminar flow state, thereby reducing convection interference with the detection process of the thermal conductivity sensor 7. Since the thermal conductivity coefficient of hydrogen is 10 times that of air, the thermal conductivity sensor 7 can accurately detect the hydrogen content in the gas passing through 805. The gas passing through the parallel gas flow channel 805 passes through the gas outlet dispersion chamber 804, the laminar flow chamber outlet 802, the exhaust two-position three-way valve 9, the inlet two-position three-way valve 11, the air pump 12, and the ceramic membrane tube 13, and is dispersed in the sample in the balancing chamber 15 in the form of small bubbles. Due to gas-liquid mass transfer between the bubbles and the sample, the hydrogen gradually equilibrates between the gas phase and the liquid phase as the gas circulation time increases. Due to the extremely low partial pressure of hydrogen in the gas and considering the solubility of hydrogen, the hydrogen content in the sample after equilibrium is negligible.

[0022] As the cycle time continues to increase, the hydrogen concentration detected by the thermal conductivity sensor 7 gradually increases until it stabilizes at 2%. Since the gas volume is 20 ml, the gas phase hydrogen volume is 0.4 ml, that is, the dissolved hydrogen content in the sample is 0.4 ml, or 0.036 mg, so the dissolved hydrogen concentration in the sample is 3.6 mg / L.

[0023] Compared with the prior art, the beneficial effects of the present invention are: a dissolved hydrogen concentration detector, which adopts a thermal conductivity detector exactly the same as that of headspace gas chromatography, and adopts cyclic headspace sampling which is similar to headspace sampling. Since the circulating gas does not use a continuous carrier gas, there is no dilution process, and the detection limit is lower; at the same time, since the circulating gas completes a gas-liquid equilibrium process with the sample each time it circulates, the balance between the dissolved hydrogen in the sample and the headspace gas can be guaranteed to the greatest extent, and the measurement is more accurate. The entire device is small in size, light in weight, and low in power. It can be powered by a No. 5 battery and can be used as a handheld portable instrument. It is simple to operate and is very suitable for hydrogen water concentration detection in various environments.

[0024] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A dissolved hydrogen concentration detector, characterized in that: It includes a sample bottle, a sampling tube, a peristaltic pump, a balance chamber, an air bag, a heat exchanger, a semiconductor refrigeration sheet, an automatic drainer, a thermal conductivity sensor, a laminar flow chamber, a two-position three-way valve for exhaust, a circulation pipeline, a two-position three-way valve for intake, an air pump, and a disperser; The peristaltic pump is located on the pipeline of the sampling tube, and its function is to inject the water sample to be tested in the sampling tube into the balance chamber through the sampling tube; The balancing chamber is a hollow cylindrical chamber, and the disperser is located inside the balancing chamber; the airbag is sealed and connected to the top of the balancing chamber, and the top of the balancing chamber is connected to the disperser through a circulation pipeline, and a heat exchanger, a laminar flow chamber, a two-position three-way valve for exhaust, a two-position three-way valve for intake, and an air pump are installed in sequence on the circulation pipeline from the top of the balancing chamber to the disperser; the function of the air pump is to transport the gas at the top of the balancing chamber to the disperser through the heat exchanger, the laminar flow chamber, the two-position three-way valve for exhaust, and the two-position three-way valve for intake to the disperser in sequence, and the interfaces of the two-position three-way valve for exhaust and the two-position three-way valve for intake that are not connected to the circulation pipeline are connected to the atmosphere; The heat exchanger is provided with an air inlet, an air outlet and a drain port of the heat exchanger, and the semiconductor cooling plate is close to the heat exchanger, and its function is to cool the gas passing through the inside of the heat exchanger through the semiconductor cooling plate; the automatic drain valve is provided with a water inlet and a drain port, and the water inlet and the drain port of the automatic drain valve are respectively connected with the water outlet of the heat exchanger and the top of the balance chamber; The thermal conductivity sensor is sealed and connected to the laminar flow chamber.

2. The dissolved hydrogen concentration detector according to claim 1, characterized in that: A disperser is a device with a 10nm-100μm microporous structure on the surface of an organic membrane, an inorganic membrane, a metal sintered aeration head, etc. Its function is to disperse the gas passing through the disperser in the water in the form of small bubbles.

3. The dissolved hydrogen concentration detector according to claim 1, characterized in that: The laminar flow cavity is provided with an air inlet, an air outlet, an air inlet dispersion cavity, an air outlet dispersion cavity, and a plurality of gas flow passages which are parallel to each other and have rectangular cross sections.

4. The laminar flow chamber according to claim 1, characterized in that: The gas flows in a gas flow channel with a rectangular cross section, and the Reynolds number Re value is less than 2300, and more preferably, the Re value is less than 800.

Images