Three-stage gas sampling system

Abstract

The utility model provides a kind of three-stage gas sampling system, including the remote sampling unit, steady flow buffer unit and sample detection unit connected in turn along airflow direction, and remote sampling unit, steady flow buffer unit and sample detection unit are connected with control unit.The utility model has realized the efficient, fast, stable sampling to wide range gas, significantly improved the detection space range of vehicle-mounted inspection instrument;At the same time, it has excellent complex gas environment adaptability, effectively protects sensor, improves detection accuracy and reliability.The utility model solves the problems of short sampling distance, slow response time and other problems of traditional two-stage sampling system, and has strong engineering application value.The utility model has the advantages of significantly improving sampling distance, shortening response time, higher detection accuracy and stability.

Description

Technical Field

[0001] This utility model relates to the technical field of environmental monitoring and gas detection, and in particular to a three-stage gas sampling system suitable for vehicle-mounted inspection instruments. Background Technology

[0002] Existing vehicle-mounted inspection devices often employ a two-stage sampling system, typically including a sampling unit and a detection unit. While this type of system is simple in structure and low in cost, its performance is poor in complex inspection paths and remote gas sampling, exhibiting the following problems:

[0003] 1. Limited sampling capacity: Due to the limited flow rate of the sampling unit pump, the remote sampling and pumping capacity of the secondary sampling system is limited, and it cannot effectively extract remote gas samples. The remote sampling range is less than 10cm.

[0004] 2. The ability to dynamically track changes in gas concentration is weak, and the gas transmission lag causes the output signal of the detection unit to lag behind the gas concentration change at the sampling inlet;

[0005] 3. The sampling response time is long, making it impossible to determine the exact location of the gas leak in real time.

[0006] Utility model patent application number 201620633158.7 discloses a pump-suction sampling system for an inspection vehicle, including an inspection vehicle. The exterior of the inspection vehicle compartment is equipped with multiple suction cups for inhaling gas. Inside the inspection vehicle compartment is a leak detection device. The air inlet of the leak detection device is connected to each of the suction cups via an air inlet pipe. The exhaust port of the leak detection device is connected to an exhaust pipe, with the outlet end of the exhaust pipe extending outside the inspection vehicle compartment. The leak detection device includes a housing with an air inlet and an exhaust port. Inside the housing is an air pump and a detection mechanism for detecting the composition of the inhaled gas. The inlet end of the air pump is connected to the air inlet via a first pipe, and the outlet end of the air pump is connected to the detection mechanism via a second pipe. The detection mechanism has an exhaust end connected to the exhaust port. The aforementioned patent integrates the intake pump and the detection mechanism into a single enclosure, resulting in high equipment integration and ease of automated control. However, the patent as a whole is a single-stage sampling system, and the intake sampling is the traditional single-stage intake sampling, which has weak sampling capacity, small range, and poor environmental adaptability. Utility Model Content

[0007] To address the technical problems of short sampling distance and slow response time in existing sampling systems, this invention proposes a three-stage gas sampling system. Through distributed flow regulation of multi-stage sampling, it achieves sampling and detection over longer distances and with higher precision, adapting to scenarios with larger sampling ranges and higher response requirements, and improving the detection range (spatial distance) of the vehicle-mounted inspection instrument.

[0008] To achieve the above objectives, the technical solution of this utility model is as follows: a three-stage gas sampling system, comprising a remote sampling unit, a flow stabilization buffer unit, and a sample injection detection unit connected sequentially along the gas flow direction, wherein the remote sampling unit, the flow stabilization buffer unit, and the sample injection detection unit are all connected to a control unit. This three-stage system allows for more stable delivery of gas from the remote end to the near end.

[0009] Preferably, the remote sampling unit is equipped with a first exhaust valve, and the current stabilization buffer unit is equipped with a second exhaust valve. Both the first and second exhaust valves are connected to the control unit. The exhaust valves can be controlled by the control unit to vent the three-stage unit.

[0010] Preferably, the remote sampling unit is equipped with a remote suction / absorption device, which is connected to the air intake structure; the flow stabilization buffer unit is equipped with a flow splitter and a flow stabilization pump; the sample injection detection unit is equipped with a sensor module and a detection pump; the remote suction / absorption device is connected to the flow stabilization pump and the sensor module respectively through the flow splitter; the sensor module is connected to the detection pump; the remote suction / absorption device, the flow stabilization pump, and the detection pump are all connected to the control unit.

[0011] Preferably, the remote sampling unit further includes a filtration device, which is connected to the remote suction / absorption device via a flow diversion and pressure relief device. The flow diversion and pressure relief device diverts the flow, and the filtration device performs filtration.

[0012] Preferably, the diversion and pressure relief device is connected to the first exhaust valve; the flow stabilizing pump is connected to the second exhaust valve; and the detection pump is directly connected to the external environment.

[0013] Preferably, the diversion device is connected to the flow stabilizing pump via a buffer device.

[0014] Preferably, the buffer device is a buffer air chamber, the outlet of which is connected to the flow stabilizing pump via an air pipe, and the inlet of which is connected to one outlet of the diverting device.

[0015] Preferably, the sensor module is a gas detection device, which includes a gas chamber containing a light source, a reflector, and a gas detector. The gas detector is disposed in the optical path between the light source and the reflector. The gas outlet of the gas chamber is connected to the gas inlet of the detection pump.

[0016] Preferably, the rear end of the distal suction / suction device is provided with a grid, and the rear side of the grid is provided with a diversion and pressure relief device and a filtration device;

[0017] The filtration device has a sampling inlet at its outlet, which is connected to a flow divider via a quick-release connector. The grid allows for uniform mixing of high-flow-rate gas; the sampling port facilitates connection to a flow stabilization buffer unit.

[0018] Preferably, the remote suction / absorption device is a pump or a fan, the steady flow pump is a medium-flow diaphragm pump, and the detection pump is a small-flow precision diaphragm pump; the flow splitting device is a reducing tee connector, the three ports of which are respectively connected to the filtration device, the buffer device, and the sensor module through air pipes, and the outlet of the buffer device is connected to the steady flow pump through an air pipe; the filtration device is a water source filter.

[0019] Both the constant flow pump and the detection pump are equipped with flow sensors, which are connected to the control unit.

[0020] Compared with existing technologies, the beneficial effects of this invention are as follows: The system, along the airflow direction, sequentially includes: a first-stage remote sampling unit, a second-stage flow stabilization buffer unit, and a third-stage sample introduction and detection unit. Through the flow delivery and relay of the three-stage pump, combined with the exhaust valve and intelligent control unit, efficient, rapid, and stable gas sampling is achieved, significantly improving the detection range and response speed of the vehicle-mounted inspection instrument. It is particularly suitable for long-distance, multi-point, and continuous inspection scenarios. This invention solves the problems of short sampling distance and slow response time in traditional two-stage sampling systems, and has strong engineering application value. This invention has the following technical effects:

[0021] 1. Significantly improve sampling distance: The three-stage sampling design, especially the powerful extraction of the first-stage remote suction / absorption device, can significantly improve the remote sampling distance by more than 200%, greatly expanding the spatial detection range of the vehicle-mounted inspection instrument.

[0022] 2. Reduced response time: The first-stage remote sampling unit quickly draws the gas closer from the inlet, reducing the time it takes for the gas to travel to the instrument body. Overall system optimization (such as pipe diameter selection and inter-stage matching) further shortens the total gas transmission time from the inlet to the sensor.

[0023] 3. Higher detection accuracy and stability: The stable and accurate flow provided by the three-stage sampling system is the basis for the sensor to obtain accurate and repeatable readings; the steady flow buffer design reduces the interference of system flow pulsation on the sensor signal. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of this utility model.

[0026] Figure 2 This is a schematic diagram of the air path and circuit of Embodiment 2 of the present invention.

[0027] In the figure, 1 is the remote sampling unit, 2 is the current stabilization buffer unit, and 3 is the sample injection detection unit. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1

[0030] like Figure 1 As shown, a three-stage gas sampling system includes a remote sampling unit 1, a flow stabilization buffer unit 2, and a sample introduction detection unit 3 connected sequentially along the airflow direction. All three units are connected to a control unit. The remote sampling unit 1 provides strong initial suction to overcome internal flow resistance, rapidly and massively extracting gas from a greater distance to the near end of the system, and delivering the sample to the secondary flow stabilization buffer unit 2. The flow stabilization buffer unit 2 receives the airflow from the first stage, providing a stable and controllable medium flow rate to prepare for the third stage of precision sampling, acting as a flow matching and buffering mechanism. The sample introduction detection unit 3 delivers the gas processed by the first two stages to the sensor module with a precise, stable, and low flow rate. The control unit is electrically connected to each stage of pumps and exhaust valves; flow sensors are installed before each stage of pumps for real-time flow monitoring and feedback, and these sensors are connected to the control unit. Based on the real-time flow feedback, the pumps and exhaust valves are independently adjusted. The control unit is specifically a microcontroller, model STM32H745. Each unit is connected to the others via necessary pipelines, i.e., air lines, and exhaust valves are installed in the pipelines. Coordinated control between each unit is achieved through the control unit.

[0031] The remote sampling unit 1 has a first exhaust valve, and the flow stabilizing buffer unit 2 has a second exhaust valve. Both the first and second exhaust valves are connected to the control unit. The control unit can vent the remote sampling unit 1 by controlling the first exhaust valve, and the control unit can vent the flow stabilizing buffer unit 2 by controlling the second exhaust valve.

[0032] The remote sampling unit 1 is equipped with a remote suction / absorption device connected to the air intake structure. This device, a pump or fan, provides strong initial suction to deliver gas from a distance to the near-end flow stabilization buffer unit 2. The air intake structure, designed through CFD analysis, is specifically an elliptical, tapered-diameter structure to facilitate gas entry into the remote sampling unit 1. The flow stabilization buffer unit 2 contains a flow divider and a flow stabilization pump. The flow stabilization pump is a medium-flow diaphragm pump, model KNF PM series, providing a stable and controllable medium flow rate. Since the flow rate of the flow stabilization pump is much greater than that of the detection pump, the flow stabilization pump's flow ratio to the detection pump needs to be adjusted via a flow divider, which is a reducing tee connector. The three ports of the flow divider are connected to the filtration device, buffer device, and sensor module via air pipes, respectively. The outlet of the buffer device is connected to the flow stabilization pump via an air pipe. The stabilizing pump is a diaphragm pump, and its operation generates flow pulsations. A buffer device weakens these pulsations, providing stable fluid conditions for the detection unit and ensuring measurement accuracy and equipment reliability. A remote suction / absorption device is connected to both the stabilizing pump and the sensor module via a flow divider. The gas extracted by the remote suction / absorption device is transmitted through a long-distance pipeline to the stabilizing buffer unit 2, where the buffer device stabilizes the sampling gas flow. The sample injection and detection unit 3 contains a sensor module and a detection pump. The intake sampling unit transmits processed and stabilized gas to the sensor module for target gas detection. The sensor module is a gas detection device, including a gas chamber containing at least a light source, a reflector, and a gas detector. The gas detector, model MIRAULTRA, is positioned in the optical path between the light source and the reflector for gas identification. The detection pump actively delivers the gas to be tested from the stabilizing buffer unit 2 to the sensor module for gas detection and then extracts the gas from the sensor module and discharges it into the air. The sensor module's outlet is connected to the detection pump's inlet. The detection pump is a small-flow precision diaphragm pump, model KNF PM. The detection pump is located behind the sensor module, which contains an optical path and a gas chamber. The detection pump draws gas from the gas chamber, creating a negative pressure within it to actively deliver gas to the sample detection unit 3. The remote suction / absorption device, the constant-flow pump, and the detection pump are all connected to the control unit. Flow sensors are installed on the outlet of the buffer device and the pipeline of the constant-flow pump, as well as on the inlet of the sensor module and the pipeline of the flow divider. These flow sensors detect the flow rate in the pipelines and are all connected to the control unit.

[0033] The remote sampling unit 1 also includes a filtration device, which is connected to the remote suction / absorption device via a diversion and pressure relief device. The filtration device includes, but is not limited to, waterproof and dustproof filtration equipment, such as a water source filter of model AF2000-02. The upstream of the suction / absorption device features a low-resistance intake structure optimized using computational fluid dynamics. A grille is located at the rear end of the remote suction / absorption device to uniformly mix the remote gas extracted by the suction / absorption device and transfer it to the filtration device.

[0034] The pressure relief device is connected to the first exhaust valve; the flow stabilizing pump is connected to the second exhaust valve. The control unit dynamically adjusts the opening and closing sizes of the first and second exhaust valves based on changes in the gas concentration monitored by the system, i.e., the detection results from the sensor module, to accelerate system cleaning and recovery and protect the sensor module from impact or contamination. The detection pump is directly connected to the external environment, allowing for the direct discharge of excess gas.

[0035] Based on real-time flow feedback, the control unit can independently adjust the power / speed of the remote suction / absorption device to control the sampling negative pressure and total flow of the remote sampling unit 1. The control unit can also independently adjust the power / speed of the detection pump, primarily controlling the inlet flow and pressure stability of the sensor module.

[0036] Example 2

[0037] like Figure 2 As shown, a three-stage gas sampling system is described. The rear side of the filter device is integrally connected to the sampling inlet. The sampling inlet is connected to the diversion device of the flow stabilization buffer unit 2 via a quick-release connector. The sampling inlet is an air inlet pipe connected via a quick-release connector, which extracts the uniformly mixed gas at the grid. The remote suction / absorption device uses a high-flow-rate rotary vane pump or duct fan (such as the HI-SD series), which is connected to the air inlet structure and the diversion device respectively. The outlet of the filter device is connected to the gas path through a long-distance pipeline to achieve long-distance gas suction. The filter device is connected in series after the diversion and depressurization device for gas purification. The purified gas sample is delivered to a splitter, which then distributes the gas to the second-stage flow stabilization buffer unit 2 and the third-stage sample injection and detection unit 3. The buffer unit 2 contains a buffer chamber connected to a flow stabilization pump. The gas volume within the buffer chamber acts as a low-pressure / flow accumulator and damper, transforming the inherent discrete, pulsed volumetric discharge of the diaphragm pump into a near-continuous fluid output with significantly reduced pulsation, thus buffering pressure fluctuations. The sampled gas is then input into the gas sensor module. The control unit automatically matches the pump speed based on the flow and pressure signals at each stage, enabling continuous monitoring.

[0038] The other structures and principles are the same as in Example 1.

[0039] This invention relates to a vehicle-mounted inspection device. The system, along the airflow direction, comprises: a first-stage remote sampling unit (sampling + filtering + diversion), a second-stage flow stabilization and buffer unit (sampling + buffering), and a third-stage precision sample introduction unit (sampling + detection). Through the delivery and relay of the three-stage sampling system, combined with the exhaust valve and control unit, efficient, rapid, and stable sampling of gases over a wide range (≥1 meter) is achieved, significantly improving the detection range of the vehicle-mounted inspection device. Simultaneously, this invention possesses excellent adaptability to complex gas environments (excluding water, dust, and oil, and adapting to density differences), effectively protecting the sensor and improving detection accuracy and reliability. The control unit enables coordinated dynamic adjustment and intelligent protection of each pump stage. This invention solves the problems of short sampling distance, slow response, and poor adaptability in traditional two-stage sampling systems.

[0040] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A three-stage gas sampling system, characterized in that, It includes a remote sampling unit (1), a flow stabilizing buffer unit (2) and a sample injection detection unit (3) connected in sequence along the airflow direction. The remote sampling unit (1), the flow stabilizing buffer unit (2) and the sample injection detection unit (3) are all connected to the control unit. The remote sampling unit (1) is equipped with a remote suction / absorption device, which is connected to the air intake structure; the flow stabilizing buffer unit (2) is equipped with a flow splitting device and a flow stabilizing pump; the sample injection detection unit (3) is equipped with a sensor module and a detection pump; the remote suction / absorption device is connected to the flow stabilizing pump and the sensor module respectively through the flow splitting device; the sensor module is connected to the detection pump; the remote suction / absorption device, the flow stabilizing pump and the detection pump are all connected to the control unit.

2. The three-stage gas sampling system according to claim 1, characterized in that, The remote sampling unit (1) is provided with a first exhaust valve, and the flow stabilizing buffer unit (2) is provided with a second exhaust valve. Both the first exhaust valve and the second exhaust valve are connected to the control unit.

3. The three-stage gas sampling system according to claim 2, characterized in that, The remote sampling unit (1) also includes a filtration device, which is connected to the remote suction / absorption device via a diversion and pressure relief device.

4. The three-stage gas sampling system according to claim 3, characterized in that, The diversion and pressure relief device is connected to the first exhaust valve; the flow stabilizing pump is connected to the second exhaust valve; and the detection pump is directly connected to the external environment.

5. The three-stage gas sampling system according to claim 3 or 4, characterized in that, The diversion device is connected to a flow stabilizing pump via a buffer device.

6. The three-stage gas sampling system according to claim 5, characterized in that, The buffer device is a buffer air chamber. The outlet of the buffer air chamber is connected to the flow stabilizing pump through an air pipe, and the inlet of the buffer air chamber is connected to one outlet of the diversion device.

7. The three-stage gas sampling system according to claim 6, characterized in that, The sensor module is a gas detection device, which includes a gas chamber containing a light source, a reflector, and a gas detector. The gas detector is positioned in the optical path between the light source and the reflector. The gas outlet of the gas chamber is connected to the gas inlet of the detection pump.

8. The three-stage gas sampling system according to any one of claims 3, 4, 6, and 7, characterized in that, The rear end of the remote suction / suction device is equipped with a grid, and the rear side of the grid is equipped with a diversion and pressure relief device and a filtration device. The outlet of the filtration device is equipped with a sampling inlet, which is connected to the diversion device via a quick-release connector.

9. The three-stage gas sampling system according to claim 8, characterized in that, The remote suction / absorption device is a pump or fan, the steady flow pump is a medium flow diaphragm pump, and the detection pump is a small flow precision diaphragm pump; the flow splitting device is a reducing tee connector, the three ports of which are respectively connected to the filtration device, the buffer device, and the sensor module through air pipes, and the outlet of the buffer device is connected to the steady flow pump through an air pipe; the filtration device is a water source filter. Both the constant flow pump and the detection pump are equipped with flow sensors, which are connected to the control unit.

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