An individual sampler

Abstract

The application discloses an individual sampler, which comprises a shell, a sampling pump and a buffer chamber installed in the shell, an air inlet nozzle and an air outlet arranged on the shell, a pipeline connection between an air inlet of the sampling pump and the air inlet nozzle, one of chamber walls of the buffer chamber being an elastic diaphragm, a chamber air inlet and a chamber air outlet arranged on the buffer chamber, a pipeline connection between the chamber air inlet and an air outlet of the sampling pump, a connection between the chamber air outlet and the air outlet, a differential pressure sensor installed in the shell, an adjusting mechanism for closing or opening the chamber air outlet installed in the buffer chamber, and a storage battery for supplying power to the sampling pump. The individual sampler can convert the pulsating airflow generated by the diaphragm pump into constant airflow, and can also detect air leakage of the system, so that the air leakage of the system is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas sampling, and particularly relates to an individual sampler. BACKGROUND

[0002] The individual sampler is a kind of instrument for detecting the air quality around the carrier, which is used for sampling and detecting harmful gas or particulate matter in the environment and air. The individual sampler is a kind of special sampling equipment which can work for a long time, is small and light, easy to operate, convenient to use and stable in performance. The specific structure of the individual sampler is disclosed in the publication with the patent number 202123450826.2. Generally, the air inlet nozzle of the sampler is connected to the harmful gas absorption bottle or the particulate matter absorption filter membrane device through a pipeline, and the harmful gas absorption bottle or the particulate matter absorption filter membrane device can be clamped at the collar of the operator. In this way, the individual sampler can provide gas sampling power, and the gas enters the harmful gas absorption bottle or the particulate matter absorption filter membrane device from the vicinity of the mouth and nose of the operator, and then is discharged after passing through the sampler. The harmful gas is absorbed by the corresponding absorption material in the absorption bottle, or the particulate matter is filtered by the filter membrane. Finally, the amount of harmful gas absorbed in the absorption bottle or the amount of particulate matter in the filter membrane is detected to obtain the amount of target substance. Finally, the concentration of harmful gas or particulate matter can be obtained by dividing the amount of harmful gas or particulate matter by the gas flow sampled by the individual sampler. Therefore, the accuracy of the sampling gas flow of the sampler directly determines the accuracy of the concentration of particulate matter or harmful gas.

[0003] The sampling flow requirements for harmful gas detection and particulate matter detection are different. The orifice plate flowmeter is generally used to detect the gas flow. The orifice plate flowmeter is generally arranged upstream or downstream of the sampling pump of the individual sampler, and the gas flow of the system is obtained by pressure difference. A smaller sampling flow is required when sampling harmful gas, and a larger sampling flow is required when detecting particulate matter. However, the sampling power of the individual sampler is provided by a micro diaphragm pump, and the flow range of the diaphragm pump is fixed. The flow size can only be changed by adjusting the motor speed. However, this method can only be adjusted in a narrow range. The flow channel of the micro diaphragm pump of the existing individual sampler is connected to the constant flow buffer bin, and the size of the flow channel cannot be changed. This makes the pressure difference of the flow measurement small and the pressure change not sensitive in the case of small flow. In the case of large flow, the medium flow rate is large, the resistance is high, the power loss is large, and in addition, the current individual sampler cannot perform self-checking for gas leakage. Once the system leaks, the sampling flow may be inaccurate, and the inaccurate flow may lead to inaccurate detection results.

[0004] In order to solve the above technical problems, the patent number is: 202011055615.6 patent disclosure file discloses a kind of with precision flow regulating device's micro diaphragm pump, the diaphragm pump is increased on the basis of original pump body flow regulating device, the structure of this flow regulating device is very complex, it includes adjusting motor, speed regulating component and adjusting device.And adjusting device includes: shaft sleeve and shaft core, the circular recess is arranged in the shaft sleeve, the gas output from mixing bin can be injected into the circular recess, shaft core can enter the inside of circular recess, and the outer wall of shaft sleeve and the circular recess are provided with a plurality of holes, adjusting device enters the amplitude of circular recess by shaft core, to adjust the number of hole for gas inflow or outflow, although this structure can solve the above technical problems, but the scheme still has greater technical defects:

[0005] First, in the patent file of 202011055615.6, the structure of adjusting device is very complex, the transmission between adjusting device and adjusting motor is also very complex, the structure of rotating inner shaft core, telescopic shaft core and shaft sleeve is very complex, and since the diaphragm pump is micro pump, the overall size of these components is relatively small, the processing difficulty of overall component is very high, and the processing cost is also very high.

[0006] Second, in the patent file, flow regulating device and diaphragm pump are fixed with each other, which increases the length and size of diaphragm pump assembly, and further increases the size and weight of individual sampler.

[0007] Third, in the scheme, since diaphragm pump and flow regulating device are connected in one body, generally speaking, when diaphragm pump is damaged, it needs to be replaced together with flow regulating device, which leads to high difficulty in maintenance and replacement, and high maintenance and replacement cost.

[0008] Finally, in the patent file of 202011055615.6, in paragraphs 0031 and 0032, the sampling principle and process of small flow sampling and large flow sampling are recorded, wherein in small flow sampling, the gas sample output from air pump 200 enters from A road, and then is discharged from B road and C road, wherein B road channel is a normally open channel, and C road is an actual sampling channel, the gas flow of gas channel C road can realize small flow control, then the individual sampler needs to be connected with harmful gas absorption bottle or particulate matter absorption filter membrane device, obviously, the harmful gas absorption bottle or particulate matter absorption filter membrane device must be communicated with the discharge port of gas channel C road to realize small flow sampling, and this sampling method makes particulate matter or harmful gas pass through sampling pump and adjusting device first, and finally enters harmful gas absorption bottle or particulate matter absorption filter membrane device, so that particulate matter and harmful gas will adhere to the channel of upstream pipeline, sampling pump and adjusting device, resulting in more inaccurate sampling result. SUMMARY

[0009] The technical problem solved by the present application is to provide an individual sampler which can convert the pulsating airflow generated by a diaphragm pump into constant airflow and adjust the ventilation resistance of the system to meet the speed regulation requirement of the sampling pump.

[0010] To solve the above technical problem, the technical scheme of the present application is as follows: an individual sampler comprises a shell, a sampling pump and a buffer chamber are installed in the shell, an air inlet is arranged on the shell and connected with a harmful gas absorption bottle or a particulate matter absorption filter device, chamber air inlets and chamber air outlets are arranged on the buffer chamber, the sampling pump is provided with an air inlet and an air outlet, the sampling pump and the buffer chamber are communicated with each other and arranged between the air inlet and the air outlet to form a sampling air path, one of the chamber walls of the buffer chamber is an elastic diaphragm, a flow sensor for detecting the sampling flow is arranged on the sampling air path, an adjusting mechanism for adjusting the sectional area of the chamber air outlet is installed in the buffer chamber, and a storage battery for supplying power to the sampling pump is arranged in the shell.

[0011] As a preferred scheme, the adjusting mechanism comprises a sealing member which is slidingly or rotatably installed in the buffer chamber and driven by a linear power device or a rotary power device to move between an open position and a closed position.

[0012] As a preferred scheme, a normally open air outlet is further arranged on the buffer chamber, the normally open air outlet and the chamber air outlets are communicated with an air outlet channel, the air outlet channel is connected to the sampling air path, the linear power device or the rotary power device drives the sealing member to switch between the open position and the closed position, and the sealing member is in sealing cooperation with the corresponding chamber air outlet when in the closed position.

[0013] As a preferred scheme, the sealing member comprises a sealing rod which is axially slidingly installed in the buffer chamber, the end of the sealing rod is in sealing cooperation with the chamber air outlet, and the linear power device is installed in the buffer chamber and in transmission cooperation with the sealing rod.

[0014] As a preferred scheme, the sealing member comprises a rotary disc which is rotatably installed in the buffer chamber, the rotary disc is in sealing cooperation with the chamber wall where the chamber air outlet is located, a plurality of air vents with different diameters are arranged on the rotary disc, the rotary power device drives the rotary disc to rotate so that one of the air vents is in position cooperation with the chamber air outlet or the rotary disc seals the chamber air outlet.

[0015] As a preferred scheme, a gas guide sleeve is fixed on the buffer chamber, the gas outlet end of the gas guide sleeve is communicated with the chamber gas outlet, the sealing member comprises a piston rod and a piston installed on the end of the piston rod, the piston is axially and sealingly slidably installed in the gas guide sleeve, the piston divides the gas guide sleeve into a gas outlet chamber and an adjusting chamber, the side wall of the gas guide sleeve is provided with a plurality of axially distributed adjusting air holes, the adjusting air holes communicate the gas outlet chamber with the inner cavity of the buffer chamber, and the piston rod is driven by the linear power device.

[0016] As a preferred scheme, an outer sleeve is fixed outside the buffer chamber, a piston cavity sleeve is fixed in the outer sleeve, a communication cavity is arranged between the piston cavity sleeve and the outer sleeve, the sealing member comprises a piston rod and a piston installed on the end of the piston rod, the piston is axially and sealingly slidably installed in the piston cavity sleeve, the piston divides the piston cavity sleeve into a gas outlet chamber and an adjusting chamber, the side wall of the piston cavity sleeve is provided with a plurality of axially distributed adjusting air holes, the adjusting air holes communicate the piston cavity sleeve with the communication cavity, the gas outlet chamber is communicated with the chamber gas outlet of the buffer chamber, the outer sleeve is provided with a gas outlet, the piston rod is driven by the linear power device.

[0017] As a preferred scheme, a gas guide block is detachably fixed outside the buffer chamber, the position of the gas guide block corresponds to the positions of the chamber gas outlet and the normally open gas outlet, the gas outlet channel is arranged on the gas guide block, the gas guide block is provided with branch channels for communicating the chamber gas outlet and the normally open gas outlet with the gas outlet channel, and a hole plate corresponding to the chamber gas outlet and the normally open gas outlet is detachably installed between the corresponding branch channel and the chamber gas outlet and the branch channel and the normally open gas outlet.

[0018] As a preferred scheme, the gas inlet nozzle and the exhaust port are integrated on a gas circuit connector, the shell is provided with a mounting groove, the gas circuit connector is provided with a gas inlet communication channel and a gas outlet communication channel which are independent of each other, the shell is provided with a connecting gas nozzle and an exhaust communication channel in the mounting groove area, the gas circuit connector is detachably and sealingly fixed in the mounting groove by bolts, the gas inlet communication channel communicates the gas inlet nozzle with the connecting gas nozzle, the connecting gas nozzle is communicated with the gas inlet of the sampling pump through a pipeline, and the gas outlet communication channel and the exhaust communication channel communicate the exhaust port and the chamber gas outlet of the buffer chamber.

[0019] As a preferred scheme, a filter membrane is further arranged in the mounting groove, and the filter membrane is pressed and fixed in the mounting groove by the gas circuit connector.

[0020] The individual sampler has the following advantages: 1. The elastic diaphragm of the buffer chamber can expand when the internal air pressure of the buffer chamber is relatively large, and the elastic diaphragm can contract when the internal air pressure is relatively small, so that the air flow discharged from the buffer chamber can be stabilized, and the pulsating air flow characteristics of the diaphragm pump can be eliminated; 2. The adjusting mechanism is arranged in the interior of the buffer chamber, and the size of the buffer chamber is not increased as a whole, so that the overall size of the individual sampler is not affected, and since the adjusting mechanism can adjust the cross-sectional area of the chamber air outlet, the air resistance can be adjusted. When harmful gas detection is performed, a small flow is required, and the diaphragm pump of the individual sampler runs at a low speed to control the sampling flow. At this time, the cross-sectional area of the adjusting chamber air outlet can be reduced, and the individual sampler can still maintain a certain air resistance under the condition of small flow. In order to ensure that the flow reaches the specified flow, since the air outlet cross-sectional area is small, the diaphragm pump needs to increase the speed to reach the rated sampling flow, so that the situation that the diaphragm pump is unstable in speed or the starting torque is too small under the condition of small flow can be avoided. When particulate matter detection is performed, a large flow is required, and the cross-sectional area of the chamber air outlet can be increased. In this way, there is a large air outlet area, so that the sampling air resistance is not too large, and the speed of the diaphragm pump is not too fast, so that the sampling requirements of different flows can be met, and the volume of the individual sampler is as small as possible.

[0021] The buffer chamber is further provided with a normally open air port, the normally open air port and the chamber air outlet are communicated with the air outlet channel, the air outlet channel is connected to the sampling air path, the linear power device or the rotary power device drives the sealing member to switch between the opening position and the closing position, the sealing member is in sealing cooperation with the corresponding chamber air outlet when being in the closing position, therefore, the total air outlet cross-sectional area can be changed by sealing or not sealing the chamber air outlet by the sealing member, so that the ventilation resistance and the sampling flow of the individual sampler can be accurately adjusted, and at this time, since the total air outlet cross-sectional area is either the cross-sectional area of the normally open air port or the sum of the cross-sectional areas of the normally open air port and the chamber air outlet, therefore, the flow sensor can adopt an orifice flowmeter as the detection, the total air outlet cross-sectional area of the buffer chamber is used as the throttle orifice plate, when harmful gas detection is performed, a small flow is required, the diaphragm pump of the individual sampler needs to operate at a low speed to control the sampling flow, at this time, the chamber air outlet can be sealed and the normally open air port is always opened, since only one normally open air port is opened at this time, the cross section of the air outlet is relatively small, the individual sampler can still maintain a certain differential pressure under the condition of small flow, so that the differential pressure sensor can accurately detect the differential pressure, the differential pressure is kept in the detection range of the differential pressure sensor, the detection result is more accurate, and in order to ensure that the flow reaches the specified flow, since the air outlet cross-sectional area is small and the ventilation resistance is large, the diaphragm pump needs to increase the speed to reach the sampling flow, so that the situation that the speed of the diaphragm pump is unstable or the starting torque is small under the condition of small flow can be avoided; when particle detection is performed, the chamber air outlet can be opened, so that there is a large air outlet area, thereby avoiding that the ventilation resistance of sampling is too large under the condition of large flow, and the speed of the diaphragm pump can also be prevented from being too fast, and the whole structure is arranged in the buffer chamber, without occupying additional space, so that the sampling requirements of different flows are met, and the volume of the individual sampler is as small as possible.

[0022] Since the sealing member includes a rotary disc, the rotary disc is rotatably installed in the buffer chamber, the rotary disc is in sealing cooperation with the chamber wall where the chamber air outlet is located, a plurality of ventilation holes with different diameters are arranged on the rotary disc, the rotary power device drives the rotary disc to rotate so that one of the ventilation holes is positionally corresponding to the chamber air outlet or the rotary disc seals the chamber air outlet, the rotary disc can be driven to rotate by the rotary power device, so that the ventilation holes with different diameters on the rotary disc are corresponding to the air outlet, the size of the overall air outlet cross section can be changed, so that the sampling flow is adjusted, of course, if the air outlet needs to be sealed, the solid plate surface of the rotary disc can be sealed with the air outlet to seal the air outlet, so that the buffer chamber in the structure does not need to be opened again.

[0023] The air guide sleeve is fixed on the buffer chamber, the air outlet end of the air guide sleeve is communicated with the chamber air outlet, the sealing member comprises a piston rod and a piston installed on the end of the piston rod, the piston is axially and sealingly slidably installed in the air guide sleeve, the piston divides the air guide sleeve into an air outlet chamber and an adjusting chamber, the side wall of the air guide sleeve is provided with a plurality of axially distributed adjusting air holes, the adjusting air holes communicate the air outlet chamber with the inner cavity of the buffer chamber, and the piston rod is driven by the linear power device. Therefore, the axial movement of the piston rod driven by the linear power device drives the axial movement of the piston, changes the size of the air outlet chamber, changes the number of the adjusting air holes communicated with the air outlet chamber, changes the size of the communication cross-sectional area between the buffer chamber and the air outlet chamber, and also realizes the adjustment of the air passage resistance, and meets the requirements of different sampling conditions.

[0024] The air guide block is detachably fixed outside the buffer chamber, the position of the air guide block corresponds to the positions of the chamber air outlet and the normally open air outlet, the air outlet channel is arranged on the air guide block, the air guide block is provided with branch channels for communicating the chamber air outlet and the normally open air outlet with the air outlet channel, and the air guide block and the buffer chamber are detachably installed with hole plates corresponding to the chamber air outlet and the normally open air outlet, and each hole plate is located between the corresponding branch channel and the chamber air outlet or the branch channel and the normally open air outlet. The air guide block can better set and install the hole plates, and can also facilitate the setting of the branch channels and the communication of the air outlets, and the installation of the hole plates can replace hole plates with different hole diameters, thereby meeting the adjustment requirements of the sampling flow.

[0025] The air inlet nozzle and the air outlet are integrated on the air path connector, the housing is provided with a mounting groove, the air path connector is provided with an air inlet communication channel and an air outlet communication channel which are independent of each other, the housing is provided with a connecting air nozzle and an air outlet communication channel in the mounting groove region, the air path connector is detachably and sealingly fixed in the mounting groove through bolts, the air inlet communication channel communicates the air inlet nozzle with the connecting air nozzle, the connecting air nozzle is communicated with the air inlet of the sampling pump through a pipeline, and the air outlet communication channel and the air outlet communication channel communicate the air outlet with the chamber air outlet of the buffer chamber. The air inlet nozzle and the air outlet are integrated on the air path connector, so that they can be integrally manufactured, the air path connector can be directly injection molded by using plastic material, and a filter film is further arranged in the mounting groove, the filter film is pressed and fixed in the mounting groove by the air path connector, the filter film can provide filtration when the particulate matter absorption filter device is not installed, so that large particles are prevented from entering the sampling pump and causing damage to the pump body, and the detachable installation of the air path connector also facilitates the replacement of the filter film. BRIEF DESCRIPTION OF DRAWINGS

[0026] The application will be further described below in combination with the drawings and examples.

[0027] Figure 1 is a structural perspective view of the present invention embodiment 1 ;

[0028] Figure 2 is another angle structural perspective view of the present invention embodiment 1 ;

[0029] Figure 3 is an internal perspective view of the present invention embodiment 1 ;

[0030] Figure 4 is a side schematic view of the present invention embodiment 1 ;

[0031] Figure 5 is Figure 4 a cross-sectional view at A-A;

[0032] Figure 6 is Figure 5 an enlarged schematic view at B;

[0033] Figure 7 is a perspective view of the buffer chamber;

[0034] Figure 8 is a perspective view with the elastic septum hidden;

[0035] Figure 9 is another angle perspective view with the elastic septum hidden;

[0036] Figure 10 is a side schematic view of the buffer chamber;

[0037] Figure 11 is Figure 10 a cross-sectional view at C-C;

[0038] Figure 12 is Figure 10 a cross-sectional view at D-D;

[0039] Figure 13 is a structural schematic view of the buffer chamber of the present invention embodiment 2;

[0040] Figure 14 is a structural schematic view of the rotating disc of the present invention embodiment 2;

[0041] Figure 15 is a structural schematic view of the buffer chamber of the present invention embodiment 3;

[0042] Figure 16 is a structural schematic view of the buffer chamber of the present invention embodiment 4;

[0043] In the attached diagram: 1. Housing; 101. Connecting nozzle; 102. Pressure detection nozzle; 103. Exhaust connection channel; 104. Mounting recess; 2. Control panel; 3. Air connector; 31. Inlet nozzle; 32. Inlet connection channel; 33. Outlet connection channel; 34. Filter membrane; 35. Exhaust port; 4. Hook; 5. Sampling pump; 51. Inlet of sampling pump 5; 52. Outlet of sampling pump 5; 6. Buffer chamber; 61. Elastic diaphragm; 62. Pressure ring; 63. Mounting recess; 64. Normally open port; 65. Chamber outlet; 7. Differential pressure sensor; 8. Upstream differential pressure sensor; 9. Air guide block; 91. Outlet. 92. Branch channel; 93. Air outlet; 94. Large-diameter orifice plate; 95. Small-diameter orifice plate; 10. Chamber air inlet; 11. Adjustment mechanism; 111. Gear motor; 112. Driven gear; 113. Sealing rod; 114. Screw sleeve; 115. Drive gear; 116. Rotary disk; 1161. Vent hole; 117. Rotary power device; 118. Air guide sleeve; 119. Piston rod; 1110. Piston; 1111. Air outlet chamber; 1112. Adjustment air hole; 1113. Internal thread gear motor; 1114. Outer sleeve; 1115. Connecting cavity; 1116. Piston chamber sleeve; 12. Detection port. Detailed Implementation

[0044] The present invention will be further described in detail below through specific embodiments.

[0045] Example 1

[0046] like Figures 1 to 12 As shown, an individual sampler includes a housing 1. A sampling pump 5 and a buffer chamber 6 are installed inside the housing 1. The sampling pump 5 is a diaphragm pump. The housing 1 is equipped with an air inlet 31 and an exhaust port 35. The air inlet 31 is used to connect to a hazardous gas absorption bottle or a particulate matter absorption filter membrane device. In this embodiment, the housing 1 is also equipped with a hook 4 for easy attachment of the sampler. This hook 4 can be hooked onto the worker's belt or a special shoulder strap. The hazardous gas absorption bottle or particulate matter absorption filter membrane device is clipped to the worker's collar and connected to the air inlet 31 on the housing 1 via a hose. When the sampler is activated, gas enters through the worker's mouth and nose, passes through the hazardous gas absorption bottle or particulate matter absorption filter membrane device, and then enters the sampler. The hazardous gas is absorbed by the absorption medium in the absorption bottle, while the particulate matter is filtered by the filter membrane in the particulate matter absorption filter membrane device. Finally, the total amount of hazardous gas can be determined by detecting the hazardous gas absorbed in the absorption medium, and the total amount of particulate matter can be determined by weighing the filter membrane.

[0047] The air inlet 51 of the sampling pump 5 is in pipeline communication with the air inlet nozzle 31, one of the chamber walls of the buffer chamber 6 is an elastic diaphragm 61, the buffer chamber 6 is provided with a chamber air inlet 10 and a chamber air outlet 65, the chamber air inlet 10 is in pipeline communication with the air outlet 52 of the sampling pump 5, the chamber air outlet 65 is in communication with the air outlet 35, thus forming a sampling gas path, the sampling gas path is provided with a flow sensor for detecting the sampling flow, wherein, in the embodiment, the buffer chamber 6 is located downstream of the sampling pump, of course, the buffer chamber 6 can also be located upstream of the sampling pump, the flow sensor in the embodiment adopts an orifice flowmeter, wherein, the housing 1 is further provided with a differential pressure sensor 7 for detecting the pressure difference between the inside and outside of the buffer chamber 6, and the chamber air outlet 65 of the buffer chamber serves as a throttling element of the orifice flowmeter, the inside of the buffer chamber 6 is fixed with an adjusting mechanism 11 for adjusting the cross-sectional area of the chamber air outlet 65, and the housing 1 is provided with a storage battery for supplying power to the sampling pump 5, which can provide power for the entire sampler to ensure long-time operation.

[0048] In the embodiment, the housing 1 is further provided with an operation panel 2 for display and operation, which can display some parameters of the sampler and can be conveniently adjusted.

[0049] In the embodiment, the buffer chamber 6 is a rectangular chamber, the number of the elastic diaphragms 61 is two, the two opposite chamber walls of the buffer chamber 6 are provided with mounting recesses 63, the elastic diaphragms 61 are placed in the mounting recesses 63 and are fixed by the compression rings 62, wherein, the compression rings 62 are fixed on the mounting recesses 63 by screws to press and fix the elastic diaphragms 61, the buffer chamber 6 can effectively store and adjust the gas flow, the elastic diaphragm 61 can expand when the internal pressure of the buffer chamber 6 is high, and can contract when the internal pressure is low, so as to ensure the stable flow of the gas discharged from the buffer chamber 6 and eliminate the pulsating flow characteristics of the diaphragm pump.

[0050] In the embodiment, the adjusting mechanism 11 includes a blocking element slidingly or rotatably installed in the buffer chamber 6, the blocking element is driven by a linear power device or a rotary power device 117 to move between an open station and a closed station. By moving the blocking element between the open station and the closed station, the chamber air outlet can be closed or the cross-sectional area of the chamber air outlet 65 can be changed, the blocking element is in sealing cooperation with the corresponding chamber air outlet 65, the buffer chamber 6 is provided with a detection port 12 for detecting the internal pressure of the buffer chamber 6, and one of the detection ends of the differential pressure sensor 7 is in communication with the detection port 12.

[0051] Of course, in this embodiment, the individual sampler can adjust the ventilation resistance of the individual sampler by adjusting the cross-sectional area of the chamber outlet 65.

[0052] In this embodiment, the buffer chamber 6 is further provided with a normally open air port 64, the normally open air port 64 and the chamber outlet 65 are both in communication with an air outlet channel 91, the air outlet channel 91 is in communication with the air outlet 35, the aperture of the normally open air port 64 is smaller than the aperture of the air outlet, and in this embodiment, the exterior of the buffer chamber 6 is detachably fixed with a gas guide block 9 by a bolt, the position of the gas guide block 9 corresponds to the positions of the chamber outlet 65 and the normally open air port 64, the air outlet channel 91 is arranged on the gas guide block 9, the gas guide block 9 is provided with branch channels 92 that are in communication with the chamber outlet 65 and the normally open air port 64 and the air outlet channel 91, and the gas guide block 9 and the buffer chamber 6 are detachably installed with orifice plates that correspond to the chamber outlet 65 and the normally open air port 64 one by one, each orifice plate is located between the corresponding branch channel 92 and the chamber outlet 65 or between the branch channel 92 and the normally open air port 64, and the gas guide block 9 is further provided with an air outlet hole 93, which is in communication with the air outlet channel 91 and in turn the air outlet 35.

[0053] In this embodiment, the normally open air port 64 and the chamber outlet 65 actually form an orifice plate throttling structure in the above structure, and therefore, the pressure difference between the inside and outside of the buffer chamber 6 can be detected by the differential pressure sensor 7 to detect the air outlet flow of the buffer chamber 6.

[0054] The orifice plates in this embodiment are two, one is a small-aperture orifice plate 95 installed between the normally open air port 64 and the branch channel 92, and the other is a large-aperture orifice plate 94 installed between the chamber outlet 65 and the branch channel 92, and the orifice plates can be clamped and fixed by the gas guide block 9 and the buffer chamber 6 or can be fixed by being screwed at the air outlet. By replacing orifice plates with different apertures, the size of the air outlet cross section can be changed, and it is very convenient to adjust the flow rate.

[0055] The chamber outlet 65 of the conventional buffer chamber 6 of the existing individual sampler cannot adjust the outlet area, so the chamber outlet 65 cannot meet the requirements of very low or very high flow, that is, the range of the existing individual sampler is relatively narrow. When the outlet area of the chamber outlet 65 is fixed, the flow can only be adjusted by adjusting the speed of the diaphragm pump. For example, when the flow requirement is very low, the speed of the diaphragm pump is low, which may cause the following problems: 1. The speed of the diaphragm pump may be too low to start; 2. The speed of the diaphragm pump is low, which causes large fluctuations in airflow, affecting the stability of the airflow; 3. The speed of the diaphragm pump is low, and the overall flow is low, so the pressure difference between the buffer chamber 61 and the external pressure is small, which causes the differential pressure detection accuracy of the orifice flowmeter to be low, and the detection result is not accurate. Therefore, in order to adapt to the sampling and detection of harmful gases, the individual sampler can only set the aperture of the chamber outlet 65 to be small when it leaves the factory. However, when a large flow is required, the aperture of the chamber outlet 65 is small, so the air resistance is very large, and the speed of the diaphragm pump needs to be increased, which may cause the speed of the diaphragm pump to exceed the rated speed and cause damage to the diaphragm pump. Therefore, the range of the existing individual sampler is small.

[0056] When the individual sampler of the present embodiment needs to sample and detect harmful gases, a small flow is required, the normally open air port 64 is opened and the chamber outlet 65 is closed. At this time, the channel cross-sectional area flowing out of the buffer chamber 6 is small, so the air resistance is larger than that of the existing technology. In order to achieve the set flow, the speed of the diaphragm pump needs to be increased, so that the speed of the diaphragm pump can be close to or lower than the starting speed of the diaphragm pump during small flow sampling, and the phenomenon of shutdown or unstable speed of the diaphragm pump due to low speed can be avoided. In addition, when small flow sampling is required, only the normally open air port 64 is opened, so the pressure difference between the inside and outside of the buffer chamber is relatively large, so the orifice flowmeter has higher accuracy when detecting the pressure difference, and the detection result is more accurate.

[0057] When particulate matter sampling and detection is required, the detection flow of particulate matter is generally large, and sometimes the sampling flow can be 10 times the harmful gas sampling flow. At this time, the chamber outlet 65 can be opened, the total outlet area is increased, and the air resistance is not too large. Therefore, the diaphragm pump can meet the large flow requirement of particulate matter sampling by appropriately increasing the speed, so that the diaphragm pump can operate at a safe speed, ensuring the sampling continuity and reliability of the individual sampler.

[0058] As shown in FIG. 9, the individual sampler of the present embodiment comprises a buffer chamber 6, a diaphragm pump 7, a normally open air port 64, a chamber outlet 65, and an orifice flowmeter 8. Figure 5 , 8 , 9, 11 and Figure 12As shown, the blocking member includes a blocking rod 113, which is axially slidingly installed in the buffer chamber 6, and the end of the blocking rod 113 is sealingly matched with the chamber gas outlet 65. The linear power device is installed in the buffer chamber 6 and is drivingly matched with the blocking rod 113.

[0059] In the embodiment, the number of the chamber gas outlets 65 is one, and the number of the always-open gas outlets 64 is also one. Of course, the number of the chamber gas outlets 65 can be two, and the two chamber gas outlets 65 have different diameters, and two sets of blocking rods 113 are arranged, and each set of blocking rods 113 is driven by a corresponding linear power device, so that more combinations can be formed. Combination one: the always-open gas outlet 64 is opened, and the two chamber gas outlets 65 are closed; combination two: the always-open gas outlet 64 is opened, the small-diameter chamber gas outlet 65 is opened, and the large-diameter chamber gas outlet 65 is closed; combination three: the always-open gas outlet 64 is opened, the small-diameter chamber gas outlet 65 is closed, and the large-diameter chamber gas outlet 65 is opened; and combination four: the always-open gas outlet 64 is opened, and the two chamber gas outlets 65 are opened.

[0060] In the embodiment, the linear power device includes a reduction motor 111, the output shaft of the reduction motor 111 is fixed with a driving gear 115, the blocking rod 113 is fixed with a driven gear 112 which is meshed with the driving gear 115, the buffer chamber 6 is fixed with a screw sleeve 114, the blocking rod 113 is threadedly installed in the screw sleeve 114, the driving gear 115 drives the driven gear 112 to rotate, and the rotation of the driven gear 112 drives the blocking rod 113 to axially move, so that the blocking or opening of the chamber gas outlet 65 can be completed. Of course, the linear power device can also be a linear motor, and the blocking rod 113 is directly slidingly installed in the buffer chamber 6, and the linear motor can directly drive the blocking rod 113 to linearly slide to complete the blocking or opening.

[0061] In the embodiment, the linear power device includes a reduction motor 111, the output shaft of the reduction motor 111 is fixed with a driving gear 115, the blocking rod 113 is fixed with a driven gear 112 which is meshed with the driving gear 115, the buffer chamber 6 is fixed with a screw sleeve 114, the blocking rod 113 is threadedly installed in the screw sleeve 114, the driving gear 115 drives the driven gear 112 to rotate, and the rotation of the driven gear 112 drives the blocking rod 113 to axially move, so that the blocking or opening of the chamber gas outlet 65 can be completed. Of course, the linear power device can also be a linear motor, and the blocking rod 113 is directly slidingly installed in the buffer chamber 6, and the linear motor can directly drive the blocking rod 113 to linearly slide to complete the blocking or opening. Figure 5 and Figure 6As shown, the air inlet nozzle 31 and the air outlet 35 are integrated on the air path joint 3, the housing 1 is provided with a mounting recess 104, the air path joint 3 is provided with an air inlet communication channel 32 and an air outlet communication channel 33 which are independent of each other, the housing 1 is provided with a connecting air nozzle 101 and an air outlet communication channel 103 in the area of the mounting recess 104, the air path joint 3 is detachably and sealingly fixed in the mounting recess 104 by bolts, the air inlet communication channel 32 connects the air inlet nozzle 31 and the connecting air nozzle 101, at the same time, the housing 1 is also provided with a pressure detection nozzle 102 which is in communication with the air inlet communication channel 32, and a corresponding upstream differential pressure sensor 8 is fixed in the housing 1, one connecting port of the upstream differential pressure sensor 8 is connected with the pressure detection nozzle 102, and the other connecting port can be in communication with the outside of the individual sampler, so that the upstream differential pressure sensor 8 can detect the pressure difference between the air inlet communication channel 32 and the outside, thereby detecting the flow of upstream gas, the connecting air nozzle 101 is in communication with the air inlet 51 of the sampling pump 5 through a pipeline, the air outlet communication channel 33 and the air outlet communication channel 103 connect the air outlet 35 and the chamber air outlet 65 of the buffer chamber 6, and the air outlet 52 of the sampling pump 5 is in communication with the chamber air inlet 10 of the buffer chamber 6 through a hose.

[0062] The mounting recess 104 is also provided with a filter membrane 34 which is pressed and fixed in the mounting recess 104 by the air path joint 3, and the filter membrane 34 can filter external particles when there is no harmful gas absorption bottle or particulate matter absorption filter device connected, so as to avoid large particles from entering the sampling pump 5 and causing damage.

[0063] Example 2

[0064] As Figure 13 and Figure 14As shown, the structure in this embodiment is basically the same as that in embodiment 1, except that the structure inside the buffer chamber 6 has been changed. In this embodiment, the sealing component includes a rotating disk 116, which is rotatably installed inside the buffer chamber 6. The rotating disk 116 is sealed to the chamber wall where the chamber outlet 65 is located. The rotating disk 116 is provided with several vent holes 1161 of different diameters. The rotating power device 117 drives the rotating disk 116 to rotate so that one of the vent holes 1161 corresponds to the position of the chamber outlet 93, or the rotating disk 116 blocks the chamber outlet 65. In this embodiment, the normally open vent 64 can be omitted, and the different diameter vent holes 1161 on the rotating disk 116 can be used directly to change and adjust the outlet cross-sectional area. Of course, a normally open vent 64 can also be provided, which can also achieve the same change in the outlet cross-sectional area. The rotating power device 117 can be implemented by a geared servo motor. As for the rotation angle of the rotary disk 116 driven by the geared motor, this can be determined using existing position detection structures, such as Hall sensors.

[0065] Example 3

[0066] like Figure 15 As shown, the structure in this embodiment is basically the same as that in embodiment 1, except that a gas guide sleeve 118 is fixed on the buffer chamber 6. The gas guide sleeve 118 is fixed to the outside of the buffer chamber 6 by bolts. The air outlet end of the gas guide sleeve 118 is connected to the air outlet 65 of the chamber. The sealing component includes a piston rod 119 and a piston 1110 installed at the end of the piston rod 119. The piston 1110 is axially and slidably installed in the gas guide sleeve 118. The piston 1110 divides the gas guide sleeve 118 into an air outlet chamber 1111 and an adjustment chamber. The side wall of the gas guide sleeve 118 is provided with a plurality of axially distributed adjustment air holes 1112. The adjustment air holes 1112 connect the air outlet chamber 1111 with the inner cavity of the buffer chamber 6. The piston rod 119 is driven by the linear power device.

[0067] In this embodiment, the linear power device uses an internal thread geared motor 1113. The internal thread geared motor 1113 includes an internal threaded sleeve and a geared motor that drives the internal threaded sleeve to rotate. The internal threaded sleeve is threadedly connected to the piston rod 119 to form a screw and nut mechanism. Therefore, when the geared motor drives the internal threaded sleeve to rotate, it will drive the piston rod 119 to move axially. The piston rod 119 drives the piston 1110 to move axially, thereby changing the size of the exhaust chamber 1111. This changes the number of regulating air holes 1112 that are connected to the exhaust chamber 1111, thereby changing the cross-sectional area of ​​the connection between the buffer chamber 6 and the exhaust chamber 1111, thus achieving the adjustment of the flow range.

[0068] Of course the above-mentioned embodiments are all using the orifice plate flowmeter, of course can also use electronic flowmeter, also can realize the detection of flow.

[0069] Embodiment 4

[0070] As Figure 16 shown, the structure of the present embodiment is basically the same as that of embodiment 3, except that the outside of the buffer chamber 6 is fixed with an outer sleeve 1114, the inner of the outer sleeve 1114 is fixed with a piston cavity sleeve 1116, a communication cavity 1115 is arranged between the piston cavity sleeve 1116 and the outer sleeve 1114, the plugging member includes a piston rod 119 and a piston 1110 mounted on the end of the piston rod 119, the piston 1110 is axially and sealingly slidably mounted in the piston cavity sleeve 1116, the piston 1110 divides the piston cavity sleeve 1116 into an air outlet chamber and an adjusting chamber, the side wall of the piston cavity sleeve 1116 is provided with a plurality of axially distributed adjusting air holes 1112, the adjusting air holes 1112 communicate the piston cavity sleeve 1116 with the communication cavity 1115, the air outlet chamber 1111 communicates with the chamber air outlet of the buffer chamber 6, the outer sleeve 1114 is provided with an air outlet, and the piston rod 119 is driven by the linear power device. After the outer sleeve 1114 is arranged outside the buffer chamber 6, the outer sleeve 1114 can be located in the idle space of the shell 1, and the piston rod 119 and the internally threaded speed reducer motor 1113 are all located in the buffer chamber, so that the volume of the buffer chamber can be further reduced, and the volume of the whole sampler can also be smaller.

[0071] The above-mentioned embodiments are only the description of the preferred embodiments of the present application, and do not limit the scope of the present application. Various modifications and improvements of the technical solutions of the present application made without departing from the design spirit of the present application shall fall within the protection scope determined by the claims of the present application.

Claims

1. A personal sampler, comprising a housing, wherein a sampling pump and a buffer chamber are installed inside the housing, the housing is provided with an air inlet and an air outlet, the air inlet being for connection to a harmful gas absorption bottle or a particulate matter absorption filter membrane device, the buffer chamber is provided with a chamber air inlet and a chamber air outlet, the sampling pump is provided with an air inlet and an air outlet, the sampling pump and the buffer chamber are interconnected and disposed between the air inlet and the air outlet to form a sampling gas path; one of the chamber walls of the buffer chamber is an elastic diaphragm, and a flow sensor for detecting the sampling flow rate is provided on the sampling gas path, characterized in that: The buffer chamber is equipped with an adjustment mechanism for adjusting the cross-sectional area of ​​the chamber's air outlet. A battery for powering the sampling pump is housed within the outer casing. The adjustment mechanism includes a sealing component slidably installed within the buffer chamber, driven by a linear or rotary power device to move between an open and closed position. A gas guide sleeve is fixed to the buffer chamber, with its outlet end communicating with the chamber's air outlet. The sealing component includes a piston rod and a piston mounted at the end of the piston rod. The piston is axially and slidably installed within the gas guide sleeve, dividing it into an outlet chamber and an adjustment chamber. The sidewall of the gas guide sleeve has several axially distributed adjustment holes. The air outlet chamber is connected to the inner cavity of the buffer chamber, and the piston rod is driven by the linear power device; or the buffer chamber is fixed with an outer sleeve, and a piston sleeve is fixed inside the outer sleeve, with a connecting cavity between the piston sleeve and the outer sleeve. The sealing element includes a piston rod and a piston installed at the end of the piston rod. The piston is axially and slidably installed in the piston sleeve, and the piston divides the piston sleeve into an air outlet chamber and an adjustment chamber. The side wall of the piston sleeve is provided with several axially distributed adjustment air holes, which connect the piston sleeve to the connecting cavity. The air outlet chamber is connected to the chamber outlet of the buffer chamber. An air outlet is provided on the outer sleeve, and the piston rod is driven by the linear power device.

2. The individual sampler as described in claim 1, characterized in that: The buffer chamber is also provided with a normally open air port. Both the normally open air port and the chamber air outlet are connected to the air outlet channel. The air outlet channel is connected to the sampling air path. The linear power device or rotary power device drives the sealing component to switch between the open position and the closed position. When the sealing component is in the closed position, it is in a sealing fit with the corresponding chamber air outlet.

3. The individual sampler as described in claim 2, characterized in that: A guide block is detachably fixed to the outside of the buffer chamber. The position of the guide block corresponds to the position of the chamber's air outlet and normally open air outlet. The air outlet channel is set on the guide block. The guide block is provided with a branch channel that connects the chamber's air outlet and normally open air outlet to the air outlet channel. A perforated plate corresponding to the chamber's air outlet and normally open air outlet is detachably installed between the guide block and the buffer chamber. Each perforated plate is located between the corresponding branch channel and the chamber's air outlet, and between the branch channel and the normally open air outlet.

4. An individual sampler as described in any one of claims 1 to 3, characterized in that: The air inlet and exhaust port are both integrated on the air connector. The housing is provided with an installation groove. The air connector is provided with independent air inlet and air outlet channels. The housing is provided with a connecting air nozzle and an exhaust channel in the installation groove area. The air connector is detachably and sealed in the installation groove by bolts. The air inlet channel connects the air inlet and the connecting air nozzle. The connecting air nozzle is connected to the air inlet of the sampling pump through a pipe. The exhaust channel and the exhaust channel connect the exhaust port and the chamber outlet of the buffer chamber.

5. The individual sampler as described in claim 4, characterized in that: The installation trough is also equipped with a filter membrane, which is pressed and fixed in the installation trough by the air passage connector.

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