Semiconductor low temperature elemental mercury generator

Abstract

The present invention discloses a semiconductor low-temperature element mercury generator, which includes a gas source and a mercury pool generating chamber, wherein the gas source is connected to a carrier gas pipeline and a dilution gas pipeline, and the mercury pool generating chamber includes a semiconductor refrigeration device, a gas mixing device and a coil, wherein 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 an outlet of the coil and the dilution gas pipeline. The semiconductor low-temperature element mercury generator provided by the present invention has the advantages of simple operation and accurate concentration of mercury standard gas.

Description

Technical Field

[0001] The 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 rate, which cannot meet the needs of production experiments. Summary of the invention

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

[0004] According to the semiconductor low-temperature elemental mercury generator of 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, a pipe diameter of the mercury source section is greater than or equal to a pipe diameter 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 disposed 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 an outlet for mercury-containing standard gas.

[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, it is possible to cooperate with a dilution gas pipeline to obtain mercury vapor of target concentration. There is little manual involvement, the operation is simple, and the concentration of the obtained mercury-containing gas is highly accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of a semiconductor low-temperature elemental mercury generator according to an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of the structure of the coil of the 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 sheet; 7, cooling fan. DETAILED DESCRIPTION

[0019] 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 the semiconductor low temperature element mercury generator of the embodiment of the present invention, Figure 1 and Figure 2As shown, the semiconductor low-temperature elemental mercury generator includes a gas source 1 and a mercury pool generating chamber 4. The gas source 1 is connected to the carrier gas pipeline and the dilution gas pipeline. The mercury pool generating chamber 4 includes a semiconductor refrigeration device, a gas mixing device and a coil 5. The coil 5 is kept at a constant temperature by the semiconductor refrigeration device. The carrier gas pipeline is connected to the coil 5. The gas mixing device is connected to the gas outlet of the coil 5 and the dilution gas pipeline. The gas source 1 uses an inert gas. The carrier gas of the carrier gas pipeline enters the mercury pool generating chamber 4 and contacts the mercury in the coil 5 to obtain saturated mercury vapor. The saturated mercury vapor is mixed with the dilution gas in the gas mixing device to obtain a mercury-containing gas of standard concentration. The inert gas can be nitrogen. The semiconductor refrigeration device can be provided with a temperature sensor and a temperature controller to detect and control the temperature.

[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, Figure 1 As shown, a small flow mass flowmeter 2 is arranged on the carrier gas pipeline, and a large flow mass flowmeter 3 is arranged on the dilution gas pipeline.

[0023] Specifically, the dilution gas flow rate can be set to be 100 to 10,000 times the carrier gas flow rate. Small flow gas can ensure the gas-liquid balance between the carrier gas and mercury, and large flow dilution gas can meet the gas demand of users 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 fixing the coil 5 pipeline to 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 and ensure 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, Figure 2 As shown, 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 length of the coil 5 pipeline ranges from 0.5 to 3 m, and the pipeline adopts a three-section type, 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 can ensure that the carrier gas reaches the set temperature after entering the mercury pool generating chamber 4, and plays a preheating role. The quartz sand in the mercury source section 52 is mixed with mercury beads, and the mercury content is about 1 to 5 g, and different mercury saturated vapor concentrations are formed at different set temperatures. The quartz sand in the outlet section 53 can prevent the mercury beads from escaping and can ensure that the temperature of the mercury-containing gas flow is stable at a constant value.

[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 surface of quartz sand with a gold film can improve the adsorption of mercury beads by quartz sand and prevent the mercury beads from escaping. The material of the coil 5 pipeline is a material that has no adsorption performance for mercury, such as polytetrafluoroethylene tube, which has the characteristics of corrosion resistance and low friction coefficient.

[0030] In some embodiments, Figure 2 As shown, 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 pipeline 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, Figure 2 As shown, 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, 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, the mercury source section and the outlet section is 3:2:5. At this time, the length of the coil is most suitable, and the effects of the inlet section, the mercury source section and the outlet section are the best and can meet the preheating and heating requirements.

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

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

[0037] In some embodiments, Figure 1 As shown, 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 sheet 6 and dissipates heat for the semiconductor refrigeration sheet 6. The cold surface of the semiconductor refrigeration sheet 6 is in contact with the mercury pool generating chamber 4. The temperature control range of the semiconductor refrigeration sheet 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 sheet 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 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.

[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] Example 1, N2 is used as the gas source 1, the temperature of the mercury pool generating chamber 4 is controlled at 10°C, the total length of the coil 5 pipeline is 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 is 3:2:5, and the theoretical value of the output concentration converted to the standard condition of 0°C is 5.74μg / m3, the measured average value is 5.77μg / m3, and the relative deviation is 0.5%.

[0042] Example 2, using N2 as the gas source 1, the temperature of the mercury pool generating chamber 4 is controlled at 15°C, the total length of the coil 5 pipeline is 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 is 3:2:5, and the theoretical value of the output concentration converted to the standard condition of 0°C is 18.13μg / m3, the measured average value is 17.88μg / m3, and the relative deviation is -1.4%.

[0043] In the description of the present invention, it is to 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”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element 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] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0047] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. 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 representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

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

Claims

1. A semiconductor low-temperature elemental mercury generator, 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; The mercury pool generating chamber has a circular groove, the coil is located in the circular groove, and a heat transfer liquid is filled between the coil and the groove; The mercury pool generating chamber is made of metal material with good thermal conductivity; The coil comprises an inlet section, a mercury source section and an outlet section, wherein 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; The surface of the quartz sand in the mercury source section is coated with a gold film.

2. The semiconductor low-temperature elemental mercury generator according to claim 1, 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, 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.

4. The semiconductor low-temperature elemental mercury generator according to claim 1, 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).

5. The semiconductor low-temperature elemental mercury generator according to claim 1, characterized in that: Quartz wool is arranged at the inlet of the inlet section and the outlet of the outlet section.

6. The semiconductor low-temperature elemental mercury generator according to claim 1, 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.

7. The semiconductor low-temperature elemental mercury generator according to claim 1, 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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