High-low sampler based on large and small pump head structures and control method thereof

Abstract

According to the high-low sampler based on the large and small pump head structure and the control method of the high-low sampler, the gas path states of the large and small pump heads of a diaphragm pump are flexibly switched through a gas path switching module, a high-flow mode and a low-flow mode can be rapidly and accurately switched, and the problems that the rotating speed adjusting range of a single pump head is limited and multi-pump cooperative control is complex are solved through physical switching; in addition, the large pump head and the small pump head are clear in division of labor, and the large pump head meets rapid sampling requirements of large-scale environment monitoring and the like by means of strong pumping capacity in a high-flow mode; the small pump head independently works in a low-flow mode, stable and accurate small-flow collection is provided, and the overall sampling efficiency is improved; besides, the pressure difference probe accurately measures the pressure difference between different pump head gas paths and feeds back data to the control unit in real time, key basis is provided for gas path switching, the control unit grasps the gas path state in time according to the key basis, the flow mode is rapidly adjusted, the sampling accuracy and stability are ensured, and the sampler can adapt to various scene requirements.

Description

Technical Field

[0001] This invention relates to the field of high and low sampler technology, and in particular to a high and low sampler based on a large and small pump head structure and its control method. Background Technology

[0002] In fields such as environmental monitoring, industrial process control, and gas analysis, high and low flow samplers are widely used as key equipment for gas sample collection and flow control. Their core function is to flexibly switch between high and low flow sampling modes according to actual needs, so as to meet the requirements of gas flow and sampling accuracy in different scenarios.

[0003] Traditional high and low flow samplers have many limitations in achieving flow mode switching and sampling at different flow rates. Some early samplers mainly relied on a single pump head structure, adjusting the pump speed to change the flow rate. However, this method has a limited range of flow rate adjustment and cannot meet the accurate sampling requirements of both high and low flow rates at the same time. When a large flow rate change is required, the pump speed adjustment may not be able to quickly and stably reach the target flow rate, and the pumping efficiency at different flow rates is difficult to optimize, which affects the sampling accuracy. Summary of the Invention

[0004] In view of this, the present invention proposes a high and low sampler based on a pump head structure with large and small diameters and its control method, which can effectively solve the defects of the prior art that it is difficult to simultaneously meet the accurate sampling requirements of high flow rate and low flow rate.

[0005] The technical solution of this invention is implemented as follows:

[0006] A high / low sampler based on a large / small pump head structure includes:

[0007] The gas path switching module is used to switch the gas path status of the large and small pump heads of the diaphragm pump, realizing the conversion between high flow mode and low flow mode;

[0008] Diaphragm pumps have different pump heads, one large and one small, to achieve different pumping efficiencies. In high flow mode, both pump heads work together, while in low flow mode, the small pump head works alone.

[0009] Differential pressure probes are used to measure the pressure difference between different pump head air paths and feed it back to the control unit;

[0010] The control unit is used to control the speed of the diaphragm pump head and the air path switching module based on the pressure difference data between the air paths of different pump heads.

[0011] As a further optional embodiment of the high and low sampler based on the large and small pump head structure, the gas path switching module includes a first buffer, a second buffer, a first capillary, a second capillary, and a gas path switching valve. The specific structural design of the gas path switching module is as follows:

[0012] When the gas path switching valve is in the low flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in a short-circuit state, and part of the airflow does not participate in external sampling. The small pump head works alone, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

[0013] When the gas path switching valve is in the high flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in working condition, and part of the airflow passes through the large pump head and the second capillary tube in sequence before being discharged from the air outlet. The small pump head works together, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

[0014] As a further alternative to the high and low sampler based on the large and small pump head structure, the inner diameter of the second capillary is greater than or equal to twice the inner diameter of the first capillary, and the length of the second capillary is less than or equal to half the length of the first capillary.

[0015] As a further alternative to the high / low sampler based on the large and small pump head structure, the differential pressure probe measures the pressure difference between different pump head gas paths based on a sampling point, wherein the sampling point includes:

[0016] The first sampling point is located on the gas path at the connection between the gas outlet of the small pump head and the first capillary tube. A first pressure sensor is set at the first sampling point to collect the output pressure when the small pump head works alone.

[0017] The second source point is located on the gas path at the connection between the outlet end of the large pump head and the second capillary tube. In high flow mode, it is connected to the outlet end manifold through the high flow setting of the gas path switching valve. A second pressure sensor is installed at the second source point.

[0018] As a further alternative to the high and low sampler based on the large and small pump head structure, the connection between the first pressure sensor and the second pressure sensor and the air path adopts an equal diameter design and is equipped with a temperature compensation module.

[0019] As a further optional solution for the high and low sampler based on the large and small pump head structure, the control unit controls the gas path switching module based on the pressure difference data between the gas paths of different pump heads, specifically including:

[0020] The pressure difference value is calculated based on the pressure difference data between the air paths of different pump heads;

[0021] When the differential pressure is less than the preset threshold, it is determined to be a low flow demand. The control unit controls the gas path switching valve to switch to the low flow position and shuts off the power supply to the large pump head.

[0022] When the differential pressure exceeds the preset threshold, it is determined to be a high flow demand. The control unit controls the gas path switching valve to switch to the high flow position and simultaneously starts the large pump head. At the same time, the speed of the large and small pump heads is adjusted through the PWM signal.

[0023] A high / low sampler control method based on a pump head structure with varying sizes, specifically including:

[0024] The system is equipped with a gas path switching module and a diaphragm pump head of different sizes. The gas path switching module is used to switch the gas path status of the diaphragm pump head of different sizes to achieve the conversion between high flow mode and low flow mode. The diaphragm pump head of different sizes is used to achieve different pumping efficiencies. In high flow mode, the two pump heads work together, while in low flow mode, the small pump head works alone.

[0025] The differential pressure probe measures the pressure difference between the air paths of different pump heads and feeds it back to the control unit.

[0026] The control unit controls the speed of the diaphragm pump head and the air path switching module based on the pressure difference data between the air paths of different pump heads.

[0027] As a further optional solution to the high and low sampler control method based on the large and small pump head structure, the gas path switching module includes a first buffer, a second buffer, a first capillary, a second capillary, and a gas path switching valve. The specific structural design of the gas path switching module is as follows:

[0028] When the gas path switching valve is in the low flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in a short-circuit state, and part of the airflow does not participate in external sampling. The small pump head works alone, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

[0029] When the gas path switching valve is in the high flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in working condition, and part of the airflow passes through the large pump head and the second capillary tube in sequence before being discharged from the air outlet. The small pump head works together, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

[0030] A computing device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of any of the above-described high / low sampler control methods based on a large / small pump head structure.

[0031] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the above-described high / low sampler control methods based on a large / small pump head structure.

[0032] The beneficial effects of this invention are as follows: By flexibly switching the gas path states of the large and small pump heads of the diaphragm pump through the gas path switching module, a rapid and accurate conversion between high-flow and low-flow modes is achieved. Unlike traditional methods that rely on adjusting the speed of a single pump head or multiple independent pumps working in tandem, this design avoids the problems of limited speed adjustment range and complex multi-pump collaborative control through physical gas path switching. Furthermore, the design of the large and small pump heads of the diaphragm pump achieves different pumping efficiencies. The large pump head, operating in high-flow mode, can collect a large amount of gas in a short time due to its greater pumping capacity, meeting the needs of rapid air sampling in large-scale environmental monitoring. The small pump head, operating independently in low-flow mode, can... This system provides stable and accurate low-flow-rate gas sampling. This collaborative approach fully leverages the advantages of different pump heads, avoiding the inefficiency of a single pump head under varying flow requirements and effectively improving overall sampling efficiency. Furthermore, the differential pressure probe accurately measures the pressure difference between the gas paths of different pump heads and feeds the data back to the control unit in real time. This function provides crucial information for precise control of gas path switching. During sampling, the pressure within the gas path varies under different flow modes. By accurately measuring the differential pressure, the control unit can promptly understand the working status of the gas path and quickly control the gas path switching module based on the differential pressure data, adjusting it to the appropriate flow mode to ensure the accuracy and stability of the sampling. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the composition of a high / low sampler based on a large / small pump head structure according to the present invention;

[0035] Figure 2 This is a schematic diagram of a high / low sampler based on a large / small pump head structure according to the present invention;

[0036] Figure 3 This is a flowchart illustrating a high / low sampler control method based on a large / small pump head structure according to the present invention.

[0037] Figure 4 This is a schematic diagram of the composition of a computing device according to the present invention. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] refer to Figures 1 to 4 A high / low pressure sampler based on a large / small pump head structure includes a gas path switching module, a diaphragm pump with large and small pump heads, a differential pressure probe, and a control unit, wherein:

[0040] A gas path switching module is used to switch the gas path status of the large and small pump heads of the diaphragm pump, realizing the conversion between high flow mode and low flow mode. In some embodiments, the gas path switching module includes a first buffer, a second buffer, a first capillary, a second capillary, and a gas path switching valve. The specific structural design of the gas path switching module is as follows:

[0041] When the gas path switching valve is in the low flow position (position A), the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in a short circuit state, and part of the airflow does not participate in external sampling. The small pump head works alone, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

[0042] When the gas path switching valve is in the high flow position (B position), the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in working condition. Part of the airflow passes through the large pump head and the second capillary tube in sequence and is discharged from the air outlet. The small pump head works together. The remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence and is discharged from the air outlet.

[0043] Specifically, by setting the gas path switching valve to either a low-flow (A-position) or high-flow (B-position) setting, the sampler's operating mode is clearly divided into two types: low flow and high flow. In the low-flow position, the large pump head is short-circuited, and only the small pump head operates, suitable for scenarios requiring precise sampling of trace gases. In the high-flow position, the large pump head operates and works in conjunction with the small pump head, meeting the needs for rapid sampling of large quantities of gas. This clear mode division allows the sampler to accurately adapt to sampling tasks with different flow requirements. Using the gas path switching valve's position as the switching basis is simple and clear, reducing uncertainty and complexity during the switching process. Compared to some complex switching mechanisms, this setting can more stably achieve flow mode conversion, reducing the probability of switching failure or anomalies, and ensuring the reliability of the sampler switching between different modes.

[0044] At different flow levels, the airflow is rationally distributed and guided. At the low flow level, the airflow enters the first buffer through the inlet and is then split. The large pump head short-circuits a portion of the airflow, preventing it from participating in external sampling. The small pump head processes the remaining airflow separately, and the airflow exits after passing through the small pump head, the first capillary tube, and the second buffer in sequence. At the high flow level, a portion of the airflow exits through the large pump head and the second capillary tube, while the small pump head works together to process the remaining airflow. This design ensures that the airflow follows the optimal path in different modes, reducing airflow turbulence and energy loss. The first and second buffers effectively buffer pressure fluctuations in the airflow, making it more stable. Buffering the airflow before it enters the pump head prevents damage to the pump head due to airflow impact, extending its service life. Buffering the airflow again before it exits ensures the stability of the outlet airflow, which is beneficial for subsequent analysis and processing of the sampled gas.

[0045] The large pump head is short-circuited at low flow rate, avoiding potential interference from the large pump head during high-precision, low-flow sampling. This includes the impact of large pump head vibration and airflow fluctuations on the accuracy of low-flow sampling. At the same time, reasonable airflow distribution and buffering reduce the interference of impurities and pressure changes in the airflow on the sampling results, thus improving the accuracy and reliability of sampling.

[0046] In some embodiments, the inner diameter D1 of the first capillary and the inner diameter D2 of the second capillary satisfy D2≥2D1, and the length L1 of the first capillary and the length L2 of the second capillary satisfy L2≤0.5L1. This ratio makes the resistance R2 of the second capillary forming a large pump head short-circuit loop in low flow mode less than 10% of the airflow resistance R1 of the first capillary in low flow mode, that is, R2≤0.1R1.

[0047] Specifically, in low-flow mode, the large pump head is in a short-circuit state, and the second capillary forms a short-circuit loop for the large pump head. Since the resistance R2 of the second capillary forming the short-circuit loop for the large pump head in low-flow mode is less than 10% of the airflow resistance R1 of the first capillary in low-flow mode (i.e., R2≤0.1R1), this means that during low-flow sampling, the airflow mainly flows through the small pump head and related gas paths, and the interference of the large pump head short-circuit loop on the low-flow gas path is minimal. This ensures that the small pump head can work stably as designed, accurately collect trace gas samples, and meet the requirements of high-precision low-flow sampling.

[0048] When in high flow mode, the large pump head and the small pump head work simultaneously. The inner diameter of the first capillary D1 and the inner diameter of the second capillary D2 satisfy D2≥2D1, and the length of the second capillary L2≤0.5L1. This parameter configuration makes the second capillary relatively less obstructive to the airflow. Part of the airflow discharged from the large pump head can be discharged relatively smoothly through the second capillary and discharged from the outlet together with the airflow processed by the small pump head. This achieves reasonable distribution and efficient delivery of airflow, ensuring that the sampler can quickly and stably collect a large amount of gas in high flow mode.

[0049] A reasonable configuration of capillary parameters helps to reduce energy loss of airflow in the air path. Since the second capillary has little obstruction to the airflow in high flow mode, the large pump head does not need to consume too much energy to overcome the air path resistance. In low flow mode, the small pump head is less affected by the short-circuit cycle of the large pump head and can also maintain stable operation with lower energy consumption. Overall, this reduces the energy consumption of the sampler system, improves energy utilization efficiency, extends the service life of the equipment, or reduces the energy supply requirement.

[0050] Diaphragm pumps have different pump heads, one large and one small, to achieve different pumping efficiencies. In high-flow mode, both pump heads work together, while in low-flow mode, the small pump head works alone.

[0051] Specifically, the large and small pump heads work together in high-flow mode, enabling rapid and large-volume gas delivery. This is suitable for scenarios with high flow requirements, such as factory exhaust emission monitoring and large-scale ambient air sampling, and can acquire sufficient gas samples in a short time. The small pump head works alone in low-flow mode, which can precisely control the gas flow rate and meet the extremely high flow accuracy requirements of laboratory scenarios such as high-precision analysis of trace gases and trace detection of special gases. This division of labor between the large and small pump heads allows the sampler to accurately adapt to different flow requirements, expanding its application range.

[0052] Large pump heads have a greater pumping capacity and can fully leverage their advantages in efficient gas delivery in high-flow mode to complete the collection of large amounts of gas with high efficiency. Small pump heads, on the other hand, are designed with a greater emphasis on the precision of flow control and can stably and accurately provide the required small flow of gas in low-flow mode. This approach of using different pump heads according to different flow requirements avoids the problem of low efficiency of a single pump head under different flow conditions and optimizes the overall pumping efficiency of the sampler.

[0053] A differential pressure probe is used to measure the pressure difference between different pump head gas paths and feed it back to the control unit; in some embodiments, the differential pressure probe measures the pressure difference between different pump head gas paths based on a sampling point, wherein the sampling point includes:

[0054] The first sampling point is located on the gas path at the connection between the outlet of the small pump head and the first capillary tube. A first pressure sensor is set at the first sampling point to collect the output pressure P1 when the small pump head is working alone. This position is directly connected to the low flow position gas path of the gas path switching valve through a three-way connector to ensure the accuracy of differential pressure measurement in low flow mode.

[0055] The second sampling point is located on the gas path at the connection between the outlet end of the large pump head and the second capillary tube. In high-flow mode, it is connected to the outlet manifold through the high-flow setting of the gas path switching valve. It is used to collect the output pressure P2 of the large pump head. A second pressure sensor is set at the second sampling point. At the same time, this position forms a differential pressure measurement pair with the first sampling point through a bypass pipeline. It is used to calculate the dynamic difference ΔP=P2-P1 between the output pressure of the two pump heads in high-flow mode.

[0056] Specifically, the first sampling point is located on the gas path at the connection between the outlet of the small pump head and the first capillary tube, specifically used to collect the output pressure P1 of the small pump head when it is working alone; the second sampling point is located on the gas path at the connection between the outlet of the large pump head and the second capillary tube, used to collect the output pressure P2 of the large pump head. This targeted setting ensures that the pressure data of the corresponding pump head can be accurately obtained under different flow modes, providing a reliable basis for differential pressure calculation; the first sampling point is directly connected to the low-flow gas path of the gas path switching valve through a three-way connector. In low-flow mode, this connection method avoids pressure loss and interference caused by gas path branches, bends, etc., ensuring the accuracy of the measurement of the output pressure P1 of the small pump head; the second sampling point is connected to the outlet manifold through the high-flow setting of the gas path switching valve in high-flow mode, and forms a differential pressure measurement pair with the first sampling point through a bypass pipeline. This allows the dynamic difference ΔP=P2-P1 of the output pressure difference between the two pump heads to be calculated in real time and accurately in high-flow mode, reflecting the actual pressure change of the gas path in high-flow mode;

[0057] The differential pressure probe feeds back the measured differential pressure data between different pump head gas paths to the control unit. Based on this differential pressure data and a preset control strategy, the control unit can accurately determine the current gas path status and flow demand, thereby precisely controlling the operation of the gas path switching module to achieve stable switching between high-flow and low-flow modes. In high-flow mode, by monitoring the change in ΔP in real time, the control unit can adjust the operating parameters of the large and small pump heads, such as rotational speed, to maintain a stable flow output. In low-flow mode, based on the measured value of P1, the control unit can precisely control the operating state of the small pump head, ensuring the accuracy and stability of low-flow sampling.

[0058] In some embodiments, the connection between the first and second pressure sensors and the air path is designed with equal diameter and is equipped with a temperature compensation module.

[0059] Specifically, the connection between the first and second pressure sensors and the gas path adopts an equal diameter design, which avoids flow field interference phenomena such as changes in airflow velocity and eddies caused by sudden changes in pipe diameter. When the gas flows through the sensor connection, the equal diameter structure allows the airflow to transition smoothly, reducing the error caused by the instability of the flow field to the pressure measurement, and ensuring that the sensor can accurately sense the real pressure in the gas path.

[0060] The temperature compensation module effectively eliminates the impact of temperature changes on pressure measurements. At different ambient temperatures, the physical properties of gases (such as density and viscosity) change, affecting the accuracy of pressure measurements. The temperature compensation module corrects the pressure measurements based on real-time temperature data, ensuring high accuracy under various temperature conditions.

[0061] A control unit is used to control the rotational speed of the diaphragm pump head (large and small pump heads) and the gas path switching module based on the pressure difference data between the gas paths of different pump heads; in some embodiments, the control unit controls the gas path switching module based on the pressure difference data between the gas paths of different pump heads, specifically including:

[0062] The pressure difference value is calculated based on the pressure difference data between the air paths of different pump heads;

[0063] When the differential pressure is less than the preset threshold, it is determined to be a low flow demand. The control unit controls the gas path switching valve to switch to the low flow position and shuts off the power supply to the large pump head.

[0064] When the differential pressure exceeds the preset threshold, it is determined to be a high flow demand. The control unit controls the gas path switching valve to switch to the high flow position and simultaneously starts the large pump head. At the same time, the speed of the large and small pump heads is adjusted through the PWM signal.

[0065] Specifically, the control unit can calculate the pressure difference value based on the pressure difference data between different pump head gas paths and compare it with a preset threshold to automatically determine whether the current demand is low or high flow rate. This intelligent judgment method does not require manual intervention and can adjust the sampler's flow mode in real time according to the actual gas path pressure, improving the sampler's automation level and response speed. When it is determined to be a low flow rate demand, the control unit precisely controls the gas path switching valve to switch to the low flow level and shuts off the power supply to the large pump head. When it is determined to be a high flow rate demand, it quickly switches the gas path switching valve to the high flow level and simultaneously starts the large pump head. This precise gas path level switching ensures that the sampler can operate in the best condition under different flow rate demands, improving the sampling efficiency and accuracy.

[0066] By employing a control strategy based on differential pressure data, the control unit can rationally allocate the operation of the large and small pump heads. In low-flow mode, only the small pump head operates, avoiding unnecessary operation of the large pump head and reducing energy consumption and equipment wear. In high-flow mode, the large and small pump heads work together, fully utilizing the high-flow delivery capacity of the large pump head, while the small pump head also plays an auxiliary and stabilizing role in airflow, improving overall pumping efficiency. In high-flow mode, the control unit adjusts the rotational speed of the large and small pump heads via PWM signals, dynamically adjusting the operating parameters of the pump heads according to actual flow requirements and gas path pressure conditions, making the flow output more stable and accurate, and meeting the stringent flow requirements of different sampling scenarios.

[0067] It should be noted that the specific steps for adjusting the speed of the large and small pump heads via PWM signals include:

[0068] When the high and low samplers are in high flow mode, the control unit uses a PID control algorithm to calculate the required PWM signal duty cycle in real time based on the difference between the preset high flow target flow value and the actual sampled flow.

[0069] The control unit transmits the generated PWM signal with a specific duty cycle to the drive circuits of the large pump head and the small pump head respectively.

[0070] The drive circuits for the large and small pump heads adjust the average voltage applied to the large and small pump head motors according to the duty cycle of the received PWM signal, thereby precisely controlling the speed of the large and small pump heads.

[0071] A high / low sampler control method based on a pump head structure with varying sizes, specifically including:

[0072] The system is equipped with a gas path switching module and a diaphragm pump head of different sizes. The gas path switching module is used to switch the gas path status of the diaphragm pump head of different sizes to achieve the conversion between high flow mode and low flow mode. The diaphragm pump head of different sizes is used to achieve different pumping efficiencies. In high flow mode, the two pump heads work together, while in low flow mode, the small pump head works alone.

[0073] The differential pressure probe measures the pressure difference between the air paths of different pump heads and feeds it back to the control unit.

[0074] The control unit controls the speed of the diaphragm pump head and the air path switching module based on the pressure difference data between the air paths of different pump heads.

[0075] In some embodiments, the gas path switching module includes a first buffer, a second buffer, a first capillary tube, a second capillary tube, and a gas path switching valve. The specific structural design of the gas path switching module is as follows:

[0076] When the gas path switching valve is in the low flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in a short-circuit state, and part of the airflow does not participate in external sampling. The small pump head works alone, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

[0077] When the gas path switching valve is in the high flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in working condition, and part of the airflow passes through the large pump head and the second capillary tube in sequence before being discharged from the air outlet. The small pump head works together, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

[0078] A computing device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of any of the above-described high / low sampler control methods based on a large / small pump head structure.

[0079] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the above-described high / low sampler control methods based on a large / small pump head structure.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high / low sampler based on a large / small pump head structure, characterized in that, include: The gas path switching module is used to switch the gas path status of the large and small pump heads of the diaphragm pump, realizing the conversion between high flow mode and low flow mode; Diaphragm pumps have different pump heads, one large and one small, to achieve different pumping efficiencies. In high flow mode, both pump heads work together, while in low flow mode, the small pump head works alone. Differential pressure probes are used to measure the pressure difference between different pump head air paths and feed it back to the control unit; The control unit is used to control the speed of the diaphragm pump head and the air path switching module based on the pressure difference data between the air paths of different pump heads.

2. The high / low sampler based on a large / small pump head structure according to claim 1, characterized in that, The gas path switching module includes a first buffer, a second buffer, a first capillary tube, a second capillary tube, and a gas path switching valve. The specific structural design of the gas path switching module is as follows: When the gas path switching valve is in the low flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in a short-circuit state, and part of the airflow does not participate in external sampling. The small pump head works alone, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet. When the gas path switching valve is in the high flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in working condition, and part of the airflow passes through the large pump head and the second capillary tube in sequence before being discharged from the air outlet. The small pump head works together, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

3. The high / low sampler based on a large / small pump head structure according to claim 2, characterized in that, The inner diameter of the second capillary is greater than or equal to twice the inner diameter of the first capillary, and the length of the second capillary is less than or equal to half the length of the first capillary.

4. The high / low sampler based on a large / small pump head structure according to claim 3, characterized in that, The differential pressure probe measures the pressure difference between different pump head gas paths based on a sampling point, which includes: The first sampling point is located on the gas path at the connection between the gas outlet of the small pump head and the first capillary tube. A first pressure sensor is set at the first sampling point to collect the output pressure when the small pump head works alone. The second source point is located on the gas path at the connection between the outlet end of the large pump head and the second capillary tube. In high flow mode, it is connected to the outlet end manifold through the high flow setting of the gas path switching valve. A second pressure sensor is installed at the second source point.

5. The high / low sampler based on a large / small pump head structure according to claim 4, characterized in that, The connection points between the first and second pressure sensors and the air path are designed with equal diameter and are equipped with a temperature compensation module.

6. The high / low sampler based on a large / small pump head structure according to claim 5, characterized in that, The control unit controls the gas path switching module based on the pressure difference data between different pump head gas paths, specifically including: The pressure difference value is calculated based on the pressure difference data between the air paths of different pump heads; When the differential pressure is less than the preset threshold, it is determined to be a low flow demand. The control unit controls the gas path switching valve to switch to the low flow position and shuts off the power supply to the large pump head. When the differential pressure exceeds the preset threshold, it is determined to be a high flow demand. The control unit controls the gas path switching valve to switch to the high flow position and simultaneously starts the large pump head and the small pump head. At the same time, the speed of the large and small pump heads is adjusted through the PWM signal.

7. A high / low sampler control method based on a pump head structure with varying sizes, characterized in that, Specifically, it includes: The system is equipped with a gas path switching module and a diaphragm pump head of different sizes. The gas path switching module is used to switch the gas path status of the diaphragm pump head of different sizes to achieve the conversion between high flow mode and low flow mode. The diaphragm pump head of different sizes is used to achieve different pumping efficiencies. In high flow mode, the two pump heads work together, while in low flow mode, the small pump head works alone. The differential pressure probe measures the pressure difference between the air paths of different pump heads and feeds it back to the control unit. The control unit controls the speed of the diaphragm pump head and the air path switching module based on the pressure difference data between the air paths of different pump heads.

8. The high / low sampler control method based on a large / small pump head structure according to claim 7, characterized in that, The gas path switching module includes a first buffer, a second buffer, a first capillary tube, a second capillary tube, and a gas path switching valve. The specific structural design of the gas path switching module is as follows: When the gas path switching valve is in the low flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in a short-circuit state, and part of the airflow does not participate in external sampling. The small pump head works alone, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet. When the gas path switching valve is in the high flow position, the airflow enters the first buffer through the air inlet and is split to the small pump head and the large pump head. The large pump head is in working condition, and part of the airflow passes through the large pump head and the second capillary tube in sequence before being discharged from the air outlet. The small pump head works together, and the remaining airflow passes through the small pump head, the first capillary tube and the second buffer in sequence before being discharged from the air outlet.

9. A computing device, characterized in that, The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the high / low sampler control method based on a large / small pump head structure as described in any one of claims 7-8.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the steps of the high and low sampler control method based on the large and small pump head structure as described in any one of claims 7-8.

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