Semiconductor low-temperature elemental mercury generator

Abstract

Disclosed in the present invention is a semiconductor low-temperature elemental mercury generator. The semiconductor low-temperature elemental mercury generator comprises a gas source and a mercury pool generation chamber, wherein the gas source is in communication with a carrier gas pipeline and a diluting gas pipeline; the mercury pool generation chamber comprises a semiconductor refrigerating device, a gas mixing device and a coil pipe; the coil pipe is kept at a constant temperature by means of the semiconductor refrigerating device; the carrier gas pipeline is in communication with the coil pipe; and the gas mixing device is in communication with a gas outlet of the coil pipe and the diluting gas pipeline. The semiconductor low-temperature elemental mercury generator provided in the present invention has the advantages of a simple operation and a precise concentration of a standard gas containing mercury.

Description

Semiconductor low-temperature elemental mercury generator Technical Field

[0001] The present invention relates to the technical field of gaseous mercury monitoring, and in particular to a semiconductor low-temperature elemental mercury generator. Background Art

[0002] In the simulation experiment, a gaseous mercury generator is required to produce a certain concentration of mercury-containing gas as a mercury source. The gaseous mercury generator in the related technology has a limited gas-liquid contact area, unstable temperature, and limited output gas flow, which cannot meet the needs of production experiments. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention provides a semiconductor low-temperature elemental mercury generator, which has the advantages of simple operation and accurate mercury standard gas concentration.

[0004] According to an embodiment of the present invention, the semiconductor low-temperature elemental mercury generator includes a gas source and a mercury pool generating chamber, the gas source is connected to a carrier gas pipeline and a dilution gas pipeline, the mercury pool generating chamber includes a semiconductor refrigeration device, a gas mixing device and a coil, the coil is maintained at a constant temperature by the semiconductor refrigeration device, the carrier gas pipeline is connected to the coil, and the gas mixing device is connected to the gas outlet of the coil and the dilution gas pipeline.

[0005] The semiconductor low-temperature elemental mercury generator according to the embodiment of the present invention has the advantages of simple operation and accurate concentration of mercury standard gas.

[0006] In some embodiments, a small flow mass flow meter is provided on the carrier gas pipeline, and a large flow mass flow meter is provided on the dilution gas pipeline.

[0007] In some embodiments, the mercury pool generating chamber has an annular groove, the coil is located in the annular groove, and a heat transfer fluid is filled between the coil and the groove.

[0008] In some embodiments, the coil includes an inlet section, a mercury source section, and an outlet section. The inlet section and the outlet section are both filled with quartz sand, and the mercury source section is filled with quartz sand with mercury beads.

[0009] In some embodiments, the surface of the quartz sand in the mercury source section is coated with a gold film.

[0010] In some embodiments, the pipe diameter of the mercury source section is greater than or equal to the pipe diameters of the inlet section and the outlet section.

[0011] In some embodiments, the length ratio of the inlet section, the mercury source section, and the outlet section is (2-4):(1-3):(3-6).

[0012] In some embodiments, quartz wool is provided at the inlet of the inlet section and the outlet of the outlet section.

[0013] In some embodiments, the semiconductor refrigeration device includes a semiconductor refrigeration plate and a heat dissipation fan, and the heat dissipation fan is located above the semiconductor support plate.

[0014] In some embodiments, the gas mixing device includes a tee, the gas outlet of the coil and the dilution gas pipeline are respectively connected to the first end and the second end of the tee, and the third end of the tee is the mercury-containing standard gas outlet.

[0015] The present application generates mercury vapor of standard concentration through the saturated vapor pressure method. The saturated vapor pressure of mercury is different at different temperatures. By changing the temperature through a semiconductor refrigeration device and cooperating with a dilution gas pipeline, the target concentration of mercury vapor can be obtained. There is little manual participation, the operation is simple, and the concentration of the obtained mercury-containing gas is highly accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic structural diagram of a semiconductor low-temperature elemental mercury generator according to an embodiment of the present invention.

[0017] FIG2 is a schematic structural diagram of a coil of a semiconductor low-temperature elemental mercury generator according to an embodiment of the present invention.

[0018] Figure numerals: 1, gas source; 2, small flow mass flowmeter; 3, large flow mass flowmeter; 4, mercury pool generating chamber; 5, coil; 51, inlet section; 52, mercury source section; 53, outlet section; 54, quartz wool; 6, semiconductor refrigeration plate; 7, cooling fan. DETAILED DESCRIPTION

[0019] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0020] According to an embodiment of the present invention, a semiconductor low-temperature elemental mercury generator, as shown in Figures 1 and 2, comprises a gas source 1 and a mercury pool generating chamber 4. The gas source 1 is connected to a carrier gas pipeline and a dilution gas pipeline. The mercury pool generating chamber 4 comprises a semiconductor refrigeration device, a gas mixing device, and a coil 5. The coil 5 is maintained at a constant temperature by the semiconductor refrigeration device. The carrier gas pipeline is connected to the coil 5, and the gas outlet of the gas mixing device and the coil 5 is connected to the dilution gas pipeline. The gas source 1 uses an inert gas. The carrier gas from the carrier gas pipeline enters the mercury pool generating chamber 4 and contacts the mercury in the coil 5 to produce saturated mercury vapor. The saturated mercury vapor is then mixed with the dilution gas in the gas mixing device to produce a mercury-containing gas of a standard concentration. The inert gas can be nitrogen. The semiconductor refrigeration device can be equipped with a temperature sensor and a temperature controller for temperature detection and control.

[0021] The semiconductor low-temperature elemental mercury generator according to the embodiment of the present invention has the advantages of simple operation and accurate concentration of mercury standard gas.

[0022] In some embodiments, as shown in FIG1 , a small-flow mass flowmeter 2 is provided on the carrier gas pipeline, and a large-flow mass flowmeter 3 is provided on the dilution gas pipeline.

[0023] Specifically, the dilution gas flow rate can be set to 100 to 10,000 times the carrier gas flow rate. A small flow rate of gas can ensure the gas-liquid equilibrium between the carrier gas and mercury, while a large flow rate of dilution gas can meet the user's gas demand within a large flow range.

[0024] In some embodiments, the mercury pool generating chamber 4 has an annular groove, the coil 5 is located in the annular groove, and a heat transfer liquid is filled between the coil 5 and the groove.

[0025] Specifically, the mercury pool generating chamber 4 is made of a metal material with good thermal conductivity. The annular groove facilitates the fixing of the coil 5 pipeline, which can prevent the coil 5 from twisting and detaching from the mercury pool generating chamber 4, causing poor contact and poor heat dissipation effect. Filling the space between the coil 5 and the annular groove with heat transfer liquid can increase the heat transfer area between the coil 5 and the mercury pool generating chamber 4, ensuring the thermal conductivity. The heat transfer liquid can be heat transfer oil, which can ensure that the coil 5 pipeline is evenly heated and consistent with the temperature of the semiconductor refrigeration device.

[0026] In some embodiments, as shown in FIG2 , the coil 5 includes an inlet section 51 , a mercury source section 52 and an outlet section 53 . The inlet section 51 and the outlet section 53 are both filled with quartz sand, and the mercury source section 52 is filled with quartz sand with mercury beads.

[0027] Specifically, the coil 5 has a length ranging from 0.5 to 3 meters and is a three-section structure, with an inlet section 51, a mercury source section 52, and an outlet section 53 arranged in sequence along the carrier gas flow direction. The quartz sand in the inlet section 51 ensures that the carrier gas reaches the set temperature upon entering the mercury pool generating chamber 4, thus preheating the gas. The quartz sand in the mercury source section 52 is mixed with mercury beads, with a mercury content of approximately 1 to 5 grams, to produce different mercury saturated vapor concentrations at different set temperatures. The quartz sand in the outlet section 53 prevents the mercury beads from escaping and ensures that the temperature of the mercury-containing gas flow remains constant.

[0028] In some embodiments, the surface of the quartz sand in the mercury source section 52 is coated with a gold film.

[0029] Specifically, coating the quartz sand with a gold film can enhance the quartz sand's adsorption of mercury beads, preventing them from escaping. The coil 5 is made of a material that has no mercury adsorption properties, such as polytetrafluoroethylene (PTFE), which is corrosion-resistant and has a low friction coefficient.

[0030] In some embodiments, as shown in FIG. 2 , the pipe diameter of the mercury source section 52 is greater than or equal to the pipe diameters of the inlet section 51 and the outlet section 53 .

[0031] Specifically, the mercury source section has a diameter of 5 to 30 mm, and the pipe diameter of the mercury source section 52 is larger than the inlet section 51 and the outlet section 53. The flow velocity of the carrier gas in the mercury source section 52 decreases as the diameter increases, thereby extending the contact time between the carrier gas and mercury, and enabling better contact between the carrier gas and mercury.

[0032] In some embodiments, as shown in FIG2 , the length ratio of the inlet section 51 , the mercury source section 52 , and the outlet section 53 is (2-4):(1-3):(3-6).

[0033] Specifically, among the lengths of the inlet section 51, the mercury source section 52 and the outlet section 53, the length of the inlet section 51 is adapted to the preheating requirement, the mercury source section 52 is the shortest to reduce the volume of saturated mercury vapor, and the length of the outlet section 53 meets the constant temperature heating requirement for the mercury-containing gas flow. The length ratio of the inlet section to the other sections ranges from 2 to 4, the length ratio of the mercury source section to the other sections ranges from 1 to 3, and the length ratio of the outlet section to the other sections ranges from 3 to 6.

[0034] Preferably, the length ratio of the inlet section, mercury source section, and outlet section is 3:2:5. In this case, the coil length is most suitable, and the inlet section, mercury source section, and outlet section have the best effects and can meet the preheating and heating requirements.

[0035] In some embodiments, as shown in FIG. 2 , quartz wool 54 is provided at both the inlet of the inlet section 51 and the outlet of the outlet section 53 .

[0036] Specifically, the quartz wool 54 plugged at both ends of the coil 5 can prevent the leakage of quartz sand and ensure the quantity of quartz sand. The mesh number of the quartz sand is 20 to 100 meshes.

[0037] In some embodiments, as shown in FIG1 , the semiconductor refrigeration device includes a semiconductor refrigeration sheet 6 and a heat dissipation fan 7 , and the heat dissipation fan 7 is located above the semiconductor refrigeration sheet 6 .

[0038] Specifically, the cooling fan 7 is connected to the semiconductor refrigeration plate 6 and dissipates heat for the semiconductor refrigeration plate 6. The cold surface of the semiconductor refrigeration plate 6 is in contact with the mercury pool generating chamber 4. The temperature control range of the semiconductor refrigeration plate 6 is -10 to 50°C, and the temperature control accuracy is <0.02°C. The semiconductor refrigeration device adjusts and maintains the internal temperature of the mercury pool generating chamber 4 through the semiconductor refrigeration plate 6. The outside of the mercury pool generating chamber 4 is covered with insulation material to achieve constant internal temperature.

[0039] In some embodiments, the gas mixing device includes a tee, the gas outlet of the coil 5 and the dilution gas pipeline are connected to the first end and the second end of the tee respectively, and the third end of the tee is the outlet of the mercury-containing standard gas.

[0040] Specifically, the gas mixing device may further include a gas mixing chamber, the third end of the tee is connected to the gas mixing chamber, and the mercury-containing carrier gas and the dilution gas are mixed in the gas mixing chamber to form a mercury-containing gas of standard concentration.

[0041] In Example 1, N2 was used as the gas source 1, the temperature of the mercury pool generating chamber 4 was controlled at 10°C, the total length of the coil 5 was 2 meters, the length ratio of the inlet section 51 quartz sand, the mixed mercury bead quartz sand, and the outlet section 53 quartz sand was 3:2:5, and the theoretical output concentration converted to the standard condition of 0°C was 5.74 μg / m3, the measured average value was 5.77 μg / m3, and the relative deviation was 0.5%.

[0042] In Example 2, N2 was used as the gas source 1, the temperature of the mercury pool generating chamber 4 was controlled at 15°C, the total length of the coil 5 was 2 meters, the length ratio of the inlet section 51 quartz sand, the mixed mercury bead quartz sand, and the outlet section 53 quartz sand was 3:2:5, and the theoretical output concentration converted to the standard condition of 0°C was 18.13 μg / m3, the measured average value was 17.88 μg / m3, and the relative deviation was -1.4%.

[0043] 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", "clockwise", "counterclockwise", "axial", "radial", "circumferential" 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.

[0044] Furthermore, 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0045] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0046] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0047] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0048] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Any changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are within the scope of protection of the present invention.

Claims

1. A semiconductor low temperature elemental mercury generator, It is characterized in that include: A gas source, the gas source is connected to the carrier gas pipeline and the dilution gas pipeline, A mercury pool generating chamber, the mercury pool generating chamber comprising a semiconductor refrigeration device, a gas mixing device and a coil, the coil is kept at a constant temperature by the semiconductor refrigeration device, the carrier gas pipeline is connected to the coil, and the gas mixing device is connected to the gas outlet of the coil and the dilution gas pipeline.

2. The semiconductor low-temperature elemental mercury generator according to claim 1, It is characterized in that A small flow mass flow meter is arranged on the carrier gas pipeline, and a large flow mass flow meter is arranged on the dilution gas pipeline.

3. The semiconductor low-temperature elemental mercury generator according to claim 1, It is characterized in that The mercury pool generating chamber has an annular groove, the coil is located in the annular groove, and a heat transfer liquid is filled between the coil and the groove.

4. The semiconductor low-temperature elemental mercury generator according to claim 3, It is characterized in that The coil comprises an inlet section, a mercury source section and an outlet section. The inlet section and the outlet section are both filled with quartz sand, and the mercury source section is filled with quartz sand with mercury beads.

5. The semiconductor low-temperature elemental mercury generator according to claim 4, It is characterized in that The surface of the quartz sand in the mercury source section is coated with a gold film.

6. The semiconductor low-temperature elemental mercury generator according to claim 4, It is characterized in that The pipeline diameter of the mercury source section is greater than or equal to the pipeline diameters of the inlet section and the outlet section.

7. The semiconductor low-temperature elemental mercury generator according to claim 4, It is characterized in that The length ratio of the inlet section, the mercury source section and the outlet section is (2-4):(1-3):(3-6).

8. The semiconductor low-temperature elemental mercury generator according to claim 4, It is characterized in that Quartz wool is arranged at the inlet of the inlet section and the outlet of the outlet section.

9. The semiconductor low-temperature elemental mercury generator according to claim 1, It is characterized in that The semiconductor refrigeration device comprises a semiconductor refrigeration plate and a heat dissipation fan, and the heat dissipation fan is located above the semiconductor support plate.

10. The semiconductor low temperature element mercury generator according to claim 1, It is characterized in that The gas mixing device comprises a tee, the gas outlet of the coil and the dilution gas pipeline are respectively connected to the first end and the second end of the tee, and the third end of the tee is an outlet for mercury-containing standard gas.

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