A gas sampling adapter and gas detection device

Abstract

The application provides a gas sampling joint and a gas detection device, the joint comprising a sampling unit, an air inlet unit and an air outlet unit; a pressure relief hole is arranged on the sampling unit; the air inlet unit is communicated to the bottom of the sampling unit; and the air outlet unit is communicated to the top of the sampling unit. The device comprises the joint as described above. The beneficial effects of the application include: effectively solving the problem of sampling port pressure change caused by the mismatch between the gas source gas volume and the sampling volume when the gas detection equipment is sampling or correcting, avoiding the sensitivity change caused by the change of the gas pressure in the gas circuit of the detection equipment, and helping to improve the stability and accuracy of the gas detection result. Meanwhile, the whole joint design is simple in structure, convenient to use, and can achieve good use effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas path device, in particular, to a gas sampling joint and a gas detection device. BACKGROUND

[0002] Gas detection is an important part of analysis and detection, especially in the field of environmental protection detection, gas detection has very important significance for atmospheric pollutant concentration monitoring and tracing, and atmospheric pollution control. Due to the compressibility of gas, gas detection equipment is sensitive to changes in air pressure. For example, the gas-liquid phase flow interface chemical luminescence detection equipment has very high detection sensitivity. Therefore, the change of air pressure in the reactor cavity for gas detection sensor has a great influence on the detection sensitivity and accuracy. In the use process of gas detection equipment, first of all, standard gas source is used to calibrate the equipment. During the calibration process, a large flow of standard gas is generally used as the gas source, and a three-way valve and other gas path components are used to make part of the gas pass through the sampling port of the equipment into the detection gas path of the equipment to complete the calibration, and the other part is discharged through the exhaust end. In order to ensure the gas supply and prevent the ambient air from entering the sampling port through the exhaust end, two conditions need to be met: a large gas supply and a long exhaust pipe connected to the exhaust end. This directly leads to the change of the pressure of the sampling port affected by the gas supply and the exhaust pipe, and the pressure of the sampling port is significantly higher than the external environment pressure. Therefore, it is difficult to ensure that the air pressure conditions remain constant during calibration and detection, resulting in sensitivity differences. SUMMARY

[0003] The present application aims to solve at least one of the above problems in the prior art, and one of the objects of the present application is to provide a gas sampling joint that can maintain the gas pressure of the sampling port.

[0004] To achieve the above-mentioned purpose, the present application provides a gas sampling joint.

[0005] The joint comprises a sampling unit, a gas inlet unit and a gas outlet unit; the sampling unit is provided with a pressure relief hole; the gas inlet unit is connected to the bottom of the sampling unit; and the gas outlet unit is connected to the top of the sampling unit.

[0006] Optionally, the sampling unit can include a sampling port, a sampling channel, a sampling head and a sampling cavity; the sampling head is tubular and stands on the bottom of the sampling cavity; and the sampling port is connected to the middle part of the sampling cavity through the sampling channel and the inner tube of the sampling head.

[0007] Optionally, the gas inlet unit can be provided with a gas inlet and a gas inlet channel; and the gas inlet is connected to the bottom of the sampling cavity through the gas inlet channel.

[0008] Optionally, the exhaust unit can be provided with an exhaust port and an exhaust channel; the exhaust port is communicated to the top end of the sampling cavity through the exhaust channel.

[0009] Optionally, the upper half of the sampling cavity can be provided with a plurality of pressure relief holes in the circumferential direction.

[0010] Optionally, the inner surface of the sampling cavity can be designed in a tapered or streamlined manner.

[0011] Optionally, the shielding unit can be arranged outside the pressure relief hole.

[0012] Optionally, the shielding unit can be a cylindrical shielding shell.

[0013] Optionally, the exhaust unit can further include a vacuum pump capable of assisting in exhausting air.

[0014] In another aspect, the application provides a gas detection device, which comprises the gas sampling connector as described above.

[0015] Compared with the prior art, the application has the following beneficial effects:

[0016] (1) By using the connector, the same sampling pressure as the external air can be maintained under different gas supply flow conditions, thereby avoiding the influence of gas pressure changes on detection sensitivity and accuracy.

[0017] (2) The interference of external gas flow on the sampling process can be effectively prevented, and the stability of the detection result can be improved.

[0018] (3) The influence of air flow caused by external factors such as wind, personnel movement, equipment movement, etc. on the sampling unit air flow can be effectively prevented, and external interference can be avoided to the greatest extent. At the same time, the probability and risk of dust, rainwater, etc. entering the sampling unit can also be effectively reduced.

[0019] (4) The whole connector design is simple in structure, convenient to use, and can achieve good use effect. BRIEF DESCRIPTION OF DRAWINGS

[0020] The above and other objects and features of the application will become more apparent from the following description made with reference to the accompanying drawings, in which:

[0021] Figure 1 Fig. 1 shows a schematic diagram of the structure of a gas sampling connector according to an exemplary embodiment of the application.

[0022] Explanation of reference signs:

[0023] 1-sampling unit, 11-sampling port; 12-sampling channel; 13-sampling head; 14-sampling cavity, 141-pressure relief hole;

[0024] 2-gas inlet unit, 21-gas inlet port; 22-gas inlet channel;

[0025] 3-gas outlet unit, 31-gas outlet port; 32-gas outlet channel;

[0026] 4-shielding unit. DETAILED DESCRIPTION

[0027] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application.

[0028] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0029] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0030] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] Example embodiment 1

[0032] The present exemplary embodiment provides a gas sampling connector.

[0033] In the present embodiment, as shown in Figure 1 the connector includes a sampling unit 1, a gas inlet unit 2 and a gas outlet unit 3; the sampling unit 1 is provided with a pressure relief hole 141; the gas inlet unit 2 is communicated to the bottom of the sampling unit 1; the gas outlet unit 3 is communicated to the top of the sampling unit 1.

[0034] In the embodiment, as shown in the figure, Figure 1 The sampling unit 1 includes a sampling port 11, a sampling channel 12, a sampling head 13 and a sampling cavity 14. The sampling head 13 is tubular and stands on the bottom of the sampling cavity 14. The sampling port 11 is connected to the middle of the sampling cavity 14 through the sampling channel 12 and the inner tube of the sampling head 13. The sampling port 11 of the sampling unit 1 is located in the central position of the airflow in the sampling cavity 14, and the sampling is performed in a concentric and reverse manner from the center of the airflow, which is basically not affected by the state of the airflow. The sampling unit 1 can sample in the intake airflow while avoiding the influence of the intake airflow flow and pressure on the sampling to the greatest extent.

[0035] The prior art generally adopts a three-way mode, such as a T-shaped three-way and a Y-shaped three-way, which is equivalent to dividing the intake airflow into two branches, one for sampling and the other for emptying. However, in the existing mode, the intake mode of the intake airflow is directly opposite or obliquely opposite to the sampling port, so the airflow flow and air pressure have a great influence on the state of the sampling airflow.

[0036] In the embodiment, the intake airflow is first introduced into the sampling cavity through the intake channel to flow in a fixed direction, and then the sampling head is inserted into the bottom position of the sampling cavity, at which time the sampling head is located in the center of the sampling cavity and the sampling airflow channel is also located in the center of the sampling cavity and has a concentric circular structure. During the sampling process, the intake airflow flows downward from the bottom of the sampling cavity under the stress of the intake channel and the sampling cavity, and the sampling head samples in the opposite direction from the center position of the airflow. At this time, the direction of the intake airflow is completely opposite to that of the sampling airflow, and the influence of the state of the intake airflow on the sampling airflow is minimal.

[0037] In the embodiment, as shown in the figure, Figure 1 The intake unit 2 is provided with an intake port 21 and an intake channel 22. The intake port 21 is connected to the bottom of the sampling cavity 14 through the intake channel 22. The source gas is introduced into the sampling cavity 14 through the intake unit 2. The sampling cavity 14 itself serves as a sampling cavity and a buffer cavity, and can also be called a buffer cavity.

[0038] In the embodiment, as shown in the figure, Figure 1 The exhaust unit 3 is provided with an exhaust port 31 and an exhaust channel 32. The exhaust port 31 is connected to the top end of the sampling cavity 14 through the exhaust channel 32. The source gas is discharged through the exhaust unit 3, and the ambient air cannot flow back into the sampling cavity 14 and the sampling unit 1, thereby ensuring the detection accuracy.

[0039] In the embodiment, as shown in the figure, Figure 1As shown, the upper half of the sampling cavity 14 is provided with a plurality of pressure relief holes 141 in the circumferential direction. Since the exhaust unit 3 is directly opposite the direction of the air flow, and the front end of the sampling cavity 14 is provided with a plurality of pressure relief holes 141 in different directions, the air source entering the sampling cavity 14 can be easily exhausted to the outside environment.

[0040] In this embodiment, as shown, Figure 1 The joint further includes a shielding unit 4, which is a cylindrical shielding shell arranged outside the outer ring of the pressure relief hole 141. The shielding unit 4 can effectively prevent the influence of air flow caused by external factors (such as wind, personnel movement, equipment movement, etc.) on the air flow of the sampling unit 1, and can maximize the avoidance of external interference. At the same time, it can also effectively reduce the probability and risk of dust, rainwater and other factors entering the sampling unit 1.

[0041] In this embodiment, the inner surface of the sampling cavity is designed in a gradual and streamlined manner. The air flow of the air source is in a laminar state, flows from the outside of the sampling unit to the exhaust unit, and is exhausted from the exhaust unit and the pressure relief hole. The sampling cavity itself is connected to the air inlet channel, and the size of the air inlet channel is much smaller than the inner diameter of the sampling cavity, so there is a problem of variable diameter at the connection. That is, at this point, it is necessary to gradually enlarge the air inlet channel to the sampling cavity. On the one hand, it is necessary to prevent the sudden enlargement of the size causing turbulent flow of the air flow, and on the other hand, it is necessary to avoid the occurrence of dead volume such as corners. Therefore, the inner surface of the sampling cavity is designed in a gradual and streamlined manner.

[0042] In this embodiment, in the extreme case, such as when the air supply flow of the air source is more than 1-2 orders of magnitude larger than the sampling flow, a large flow vacuum pump can be connected to the exhaust unit to assist in exhausting. At this time, the excess air flow will be extracted from the exhaust unit by the vacuum pump, and at the same time, the outside air can also enter the upper end of the sampling cavity through the pressure relief hole from the outside of the joint and be extracted from the exhaust unit. In this process, the sampling unit can still sample from the air flow in the sampling cavity, and the air pressure of the sampling unit is the same as the external air pressure.

[0043] Example Embodiment 2

[0044] The present exemplary embodiment provides a pressure adaptive gas sampling joint. The gas sampling joint is provided with an air inlet end (air inlet unit), an air outlet end (air outlet unit), a shielding shell (shielding unit) and a sampling end, a sampling cavity, a pressure relief hole (sampling unit). The air inlet end is provided with an air inlet and an air inlet channel; the sampling end is provided with a sampling port, a sampling channel and a sampling head; the air outlet end is provided with an air outlet and an air outlet channel. The air inlet is connected to the bottom of the sampling cavity through the air inlet channel; the sampling head is tubular and stands on the bottom of the sampling cavity, and the sampling port is connected to the middle of the sampling cavity through the sampling channel and the inner tube of the sampling head. The upper half of the sampling cavity is provided with a plurality of pressure relief holes in the circumferential direction, and the outer circle of the pressure relief hole is provided with a cylindrical shielding shell. The air outlet end is provided with an air outlet, and the air outlet is connected to the top end of the sampling cavity through the air outlet channel.

[0045] When sampling ambient air, ambient air can enter the sampling cavity through the positions such as the air outlet hole, the pressure relief hole and the like of the joint connected with the outside, and enter the gas path of the detection equipment from the sampling end. At this time, the pressure of the detection gas path is leveled with the external environment air pressure.

[0046] When calibration is performed, a gas source with a larger flow rate is introduced into the sampling cavity through the air inlet end. Due to the gradual and streamline design of the inner surface of the sampling cavity, the gas flow of the gas source is in a laminar state at this time, flows from the outside of the sampling tube to the air outlet end, and is exhausted from the air outlet end and the pressure relief hole. Since the air outlet end is opposite to the direction of the gas flow, and a plurality of pressure relief holes in different directions are arranged at the front end of the sampling cavity, the gas source entering the sampling cavity can be easily exhausted to the external ambient air. At the same time, the sampling port of the sampling end is located at the central position of the gas flow in the sampling cavity, and the sampling is performed in a concentric and reverse manner from the center of the gas flow, which is basically not affected by the state of the gas flow. Therefore, even if the size of the gas flow of the gas source changes, the sampling end will maintain a state leveled with the external environment air pressure, thereby avoiding the error caused by the change of the air pressure during the calibration process. On the other hand, the gas flow of the gas source in the sampling cavity is in a directional flow state and is exhausted from the exhaust end and the pressure relief end, and the ambient air cannot flow back into the sampling cavity and the sampling end, thereby ensuring the detection accuracy.

[0047] The shielding shell is arranged outside the pressure relief hole, so that during the sampling process of the equipment, the influence of the air flow caused by external factors (such as wind, personnel movement, equipment movement and the like) on the gas flow of the sampling end can be effectively prevented, and external interference can be avoided to the greatest extent. At the same time, the probability and risk of the entry of dust, rainwater and the like into the sampling end can also be effectively reduced.

[0048] In the extreme case, such as the gas source flow is much larger than the sampling gas flow 1-2 orders of magnitude, the exhaust end can be connected to a large flow of vacuum pump to assist in emptying. At this time, the excess gas flow will be pumped from the exhaust end, while the outside air can also be from the joint outside through the pressure relief hole into the upper end of the sampling chamber and from the exhaust end. In this process, the sampling end can still be sampled from the gas flow in the sampling chamber, and the gas pressure of the sampling end is the same as the external air pressure.

[0049] Example 3

[0050] The present example provides a gas detection device, the device comprises the gas sampling joint of example 1 or example 2.

[0051] In summary, the present application provides a pressure adaptive gas sampling joint, which can maintain the same sampling pressure as the external air under different gas flow conditions, thereby avoiding the influence of gas pressure change on detection sensitivity and accuracy. At the same time, it can also effectively prevent the interference of external gas flow on the sampling process, and improve the stability of the detection result.

[0052] Although the present application has been described above by incorporating the example embodiments, it should be clear to those skilled in the art that various modifications and changes can be made to the example embodiments of the present application without departing from the spirit and scope defined by the claims.

Claims

1. A gas sampling adapter, comprising: The joint comprises a sampling unit, an air inlet unit and an air outlet unit; The sampling unit is provided with pressure relief holes; The air inlet unit is communicated to the bottom of the sampling unit; The air outlet unit is communicated to the top of the sampling unit; The sampling unit comprises a sampling port, a sampling channel, a sampling head and a sampling cavity; the sampling head is tubular and vertically arranged at the bottom of the sampling cavity; the sampling port is communicated to the middle of the sampling cavity through the sampling channel and the inner tube of the sampling head; The air inlet unit is provided with an air inlet and an air inlet channel; the air inlet is communicated to the bottom of the sampling cavity through the air inlet channel; The air outlet unit is provided with an air outlet and an air outlet channel; The air outlet is communicated to the top end of the sampling cavity through the air outlet channel; The sampling head is located at the center of the sampling cavity, and the sampling airflow channel is also located at the center of the sampling cavity and has a concentric circular structure; the inlet airflow is directed to flow from the bottom of the sampling cavity upward under the stress of the sampling cavity, and the sampling head is sampled from the central position of the airflow in the opposite direction; the inlet airflow direction is completely opposite to the sampling airflow, and the sampling is performed in a concentric and reverse manner from the center of the airflow, so that the influence of the inlet airflow state on the sampling airflow is minimized.

2. The gas sampling junction of claim 1, wherein, A plurality of pressure relief holes are arranged on the upper half of the sampling cavity in the circumferential direction.

3. The gas sampling junction of claim 1, wherein, The inner surface of the sampling cavity has a gradual and streamlined design.

4. The gas sampling tap of claim 1, wherein, The joint further comprises a shielding unit, which is arranged outside the pressure relief holes.

5. The gas sampling junction of claim 4, wherein, The shielding unit is a cylindrical shielding shell.

6. The gas sampling tap of claim 1, wherein, The air outlet unit further comprises a vacuum pump, which can assist in exhausting air.

7. A gas detection device, characterized by The device comprises the gas sampling joint according to any one of claims 1-6.

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