Metal film type gas sampling device

Abstract

The invention provides a metal film type gas sampling device. The metal film type gas sampling device comprises an electromagnet, an ejector pin assembly, a sampling device main body and a metal film, a movable pipeline penetrating through two ends of the sampling device main body is arranged in the sampling device main body, the electromagnet is in airtight connection with a first end of the sampling device main body and is aligned with a corresponding opening of the movable pipeline at the end, and the metal film covers an opening of the movable pipeline at a second end of the sampling device main body; the electromagnet comprises a push rod and a coil, the coil is used for driving the push rod to move in the axial direction, the end of the push rod is fixedly connected with the ejector pin through a connecting piece, and the ejector pin assembly is coaxial with the movable pipeline and can reciprocate in the movable pipeline; the sampling device main body is also provided with a sampling branch communicated with the movable pipeline, and the sampling branch is provided with a sampling chamber for storing sampling gas. By adopting a matching structure of the ejector pin assembly and the metal film, the electromagnet receives an external electric control signal and then drives the ejector pin to puncture the metal film, so that instantaneous sampling of gas in a closed container cylinder is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas sampling, in particular to a metal diaphragm type gas sampling device. BACKGROUND

[0002] During the operation of a sealed container such as an engine or a rapid compression expander, the in-cylinder gas is always in a high-temperature and high-pressure state. Studying the changes in the composition of the in-cylinder gas at different times has a key reference significance for optimizing the operating conditions of the equipment and selecting appropriate fuel. However, the existing technology can only collect exhaust gas after the end of the operating cycle to indirectly study the composition of the in-cylinder gas. However, at this time, the gas is no longer the original gas at a certain moment during the operation, but the exhaust gas after combustion. This limitation prevents the existing technology from achieving flexible gas sampling at different times during the cycle, making it difficult to detect the dynamic changes in the in-cylinder gas during the combustion process, and further preventing a deep exploration of the underlying influence mechanism of fuel composition, operating conditions, and other factors on pollutant emissions.

[0003] Patent document CN112284838B discloses a gas sampling probe for engine test, which aims to quickly freeze the chemical reaction of the post-combustion gas and effectively reduce the temperature of the sampling needle body, thereby improving the reliability and sampling success rate of the probe and ensuring the stable operation of the sampling system. The probe includes a sampling needle body, the head and the end of the sampling needle body are respectively provided with a collection gas inlet and a collection gas outlet, the collection gas inlet and the collection gas outlet form a through collection gas channel inside the sampling needle body, and the outer side of the collection gas channel is provided with a protective agent channel and a cooling channel. However, the sampling probe of patent document CN112284838B does not have a ejector pin and a gas sampling chamber, and cannot collect gas from an external sealed container at a controllable moment. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide a metal diaphragm type gas sampling device.

[0005] According to the present application, a metal diaphragm type gas sampling device is provided, which comprises an electromagnet, an ejector pin assembly, a sampling device body and a metal diaphragm. The sampling device body is internally provided with a movable pipe passing through both ends thereof, the electromagnet is airtightly connected to the first end of the sampling device body and is aligned with the corresponding opening of the movable pipe at the end, and the metal diaphragm covers the opening of the movable pipe at the second end of the sampling device body. The electromagnet comprises a push rod and a coil, the coil is used to drive the push rod to move along the axial direction, the end of the push rod is fixedly connected with the ejector pin assembly, and the ejector pin assembly is coaxial with the movable pipe and can move in the movable pipe under the action of the pushing force. The sampling device body is also provided with a sampling branch connected with the movable pipe, and the sampling branch is provided with a sampling chamber for storing the sampled gas.

[0006] Preferably, the movable pipeline comprises a first movable pipeline and a second movable pipeline connected head to tail, the inner diameter of the first movable pipeline is larger than that of the second movable pipeline, and a step surface is formed at the transition between the two; The first movable pipeline is arranged close to the first end of the sampling device body, the second movable pipeline is arranged close to the second end of the sampling device body, and the sampling branch is communicated with the second movable pipeline.

[0007] Preferably, the thimble assembly comprises a thimble connector and a thimble; The first end of the thimble connector is provided with a radial protrusion, the maximum radial dimension of the radial protrusion is adapted to the inner diameter of the first movable pipeline, so that the radial outer side of the radial protrusion forms an airtight connection with the inner wall of the first movable pipeline; The radial protrusion is fixedly connected to the tail end of the thimble; The radial dimension of the second end of the thimble connector is smaller than that of the radial protrusion, and is fixedly connected to the end of the push rod.

[0008] Preferably, the electromagnet further comprises a packaging cover plate, one side of the packaging cover plate is fixedly connected to the coil, and the other side is fixedly connected to the first end of the sampling device body; The packaging cover plate is annular, a radial boss is arranged on the radial inner side of the packaging cover plate, and the radial boss is surrounded on the inner side to form an opening for the push rod to pass through; A second O-ring groove is arranged on the end face of the radial boss away from the electromagnet, and a rubber O-ring is arranged in the second O-ring groove, after the gas sampling is completed, the high-pressure gas entering the first movable pipeline from the damaged part of the metal film pushes the thimble connector to move to the position farthest from the metal film, so that the end face of the radial protrusion away from the metal film is tightly pressed and fitted with the rubber O-ring in the second O-ring groove, forming an airtight connection.

[0009] Preferably, the electromagnet further comprises a packaging shell, and the packaging shell is fixedly connected to the side of the packaging cover plate connected with the coil; A first O-ring groove is arranged on the outer edge of the connecting surface of the packaging cover plate and the packaging shell, and a rubber O-ring is arranged in the groove for sealing.

[0010] Preferably, an external thread is arranged on the outer circumferential surface of the second end of the sampling device body, for fixed connection with an external sealed container, and the metal film is tightly pressed between the sealing surface of the sampling device body and the external sealed container.

[0011] Preferably, the included angle between the sampling branch and the second movable pipeline is less than 90 degrees, and the sampling branch is arranged to be inclined towards the direction close to the first end of the sampling device body.

[0012] Preferably, the sampling branch comprises a sampling section, and a tube wall of the sampling section is expanded radially to form the sampling chamber.

[0013] Preferably, the sampling chamber is provided with an outlet for discharging gas, and the outlet is normally closed, and after sampling is completed, the outlet can be connected by an external pipeline to discharge the sampled gas.

[0014] Preferably, the second end of the ejector pin connector is fixedly connected with the end of the push rod by an embedded fixing screw. The piston is provided with a recess on the side away from the electromagnet, the recess has an opening, the inner side of the recess is provided with a threaded hole, an embedded fixing screw is arranged in the threaded hole, the tail end of the ejector pin is deep into the recess, and the ejector pin is fixedly connected with the ejector pin connector by rotating the embedded fixing screw. The radial protrusion is a circular truncated cone, and the diameter of the outer circumferential surface away from one end of the metal film is greater than that of the other end.

[0015] Compared with the prior art, the present application has the following beneficial effects: 1. By adopting the cooperation structure of the ejector pin assembly and the metal film, the present application realizes the instantaneous sampling of the gas in the closed container cylinder after the electromagnet drives the ejector pin to pierce the metal film under the external electric control signal, and can flexibly adjust the sampling time sequence through the external control signal, thereby solving the problem that the prior art cannot accurately capture the instantaneous gas composition.

[0016] 2. By arranging the sealing connector and combining the rubber O-ring to form a multi-position sealing structure, the present application realizes the physical separation of the electromagnet and the high-temperature and high-pressure gas in the cylinder, effectively blocks the leakage path of the high-pressure gas, guarantees the operation stability of the sampling device under special working conditions, and achieves reliable sealing effect.

[0017] 3. By the integrated design of the sealing structure and the sampling device main body, the present application forms a temporary gas storage space, realizes the temporary storage of the instantaneous sampling gas, avoids the loss or pollution of the sampling gas, and provides a convenient condition for subsequent accurate gas composition analysis and measurement. BRIEF DESCRIPTION OF DRAWINGS

[0018] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 It is a sectional view of the overall structure of the gas sampling device mainly embodied by the present application; Figure 2 It is an exploded view of the overall structure of the gas sampling device mainly embodied by the present application; Figure 3 It is an exploded view of the local structure of the gas sampling device mainly embodied by the present application.

[0019] As shown in the drawings: DETAILED DESCRIPTION

[0020] The application will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the application. These are all within the scope of protection of the application.

[0021] The metal film type gas sampling device is designed for engine, fast compression expander and constant volume bomb, etc. The core function is to realize the accurate sampling of in-cylinder instantaneous gas composition. The structure design and working principle are as follows.

[0022] The overall structure of the device mainly includes an electromagnet 2, a thimble assembly, a sampling device body 4 and a metal film 11. The inside of the sampling device body 4 is provided with a movable pipe, the movable pipe penetrates through both ends of the sampling device body 4, the electromagnet 2 is connected in airtight manner to the first end of the sampling device body 4, and is aligned with the opening of the movable pipe at the first end; the metal film 11 covers the opening of the movable pipe at the second end of the sampling device body 4.

[0023] The electromagnet 2 includes a push rod 5 and a coil 6, the coil 6 is used to drive the push rod 5 to move in the axial direction, the end of the push rod 5 extends from the coil 6 towards one side of the sampling device body 4, and the end of the push rod 5 is coaxial with the movable pipe of the sampling device body 4.

[0024] The ejector assembly comprises an ejector connector 7 and an ejector pin 8. The first end of the ejector connector 7 is provided with a radial protrusion 71, and the side of the radial protrusion 71 away from the electromagnet 2 is provided with a recess having an opening. The inner side of the recess is provided with a threaded hole 10 and a matching embedded fixing screw. The head end of the ejector pin 8 extends into the movable pipe of the sampling device body 4, and the diameter of the movable pipe is larger than the diameter of the ejector pin 8 by a certain value, so that the ejector pin 8 can move freely in the movable pipe. The tail end of the ejector pin 8 extends into the recess of the radial protrusion 71, and the embedded fixing screw is tightened to fixedly connect the ejector pin 8 and the ejector connector 7, so that they can move synchronously. The radial protrusion 71 can be a circular truncated cone, and the outer circumferential surface thereof is a tapered surface. The diameter of the tapered surface away from one end of the metal film 11 is the largest, and the diameter of the tapered surface close to one end of the metal film 11 is the smallest. After the metal film 11 is pierced by the ejector pin 8, the high-pressure gas in the external sealed container enters the second movable pipe 162 and the first movable pipe 161 from the broken metal film 11, and then acts on the outer edge tapered surface of the radial protrusion 71 from the right side, thereby pushing the ejector connector 7 to the left to the limit position. At this time, the end surface of the radial protrusion 71 away from the metal film 11 is tightly attached to the rubber O-ring in the second O-ring groove 13, forming an airtight connection. The second end of the ejector connector 7 is provided with an axial protrusion, and the end of the push rod 5 is provided with a recess. The second end of the ejector connector 7 extends into the recess at the end of the push rod 5, and the axial protrusion and the recess are provided with corresponding threaded holes 10. The embedded fixing screw is inserted into the threaded holes 10 of the axial protrusion and the recess to fixedly connect them. Therefore, under the drive of the push rod 5, the ejector pin 8 can move coaxially and reciprocally in the movable pipe of the sampling device body 4.

[0025] The electromagnet 1 can further comprise a packaging shell 1 and a packaging cover plate 3. The packaging shell 1 and the packaging cover plate 3 can be fastened and connected by screws and threaded holes. The coil 6 is fixedly arranged on the end surface of the packaging cover plate 3 facing the packaging shell 1. The outer edge of the end surface can be provided with an annular first O-ring groove 12, and a rubber O-ring is arranged in the groove, thereby forming an initial seal at the joint of the packaging shell 1 and the packaging cover plate 3, forming a sealed gas environment inside the packaging shell 1, preventing the gas in the external sealed container from entering, and then entering the movable pipe of the sampling device body 4, thereby polluting the sampling gas. The end surface of the packaging cover plate 3 away from the packaging shell 1 is provided with a hollow threaded connection part 31. The threaded connection part is provided with an opening on the side of the packaging cover plate 3 facing the packaging shell 1, providing a passage for the ejector pin 8 to pass through. The first end of the sampling device body 4 is provided with a threaded joint 41. The threaded connection part and the threaded joint are provided with matching internal and external connection threads 15. The two are matched, so that the sampling device body 4 and the packaging cover plate 3 are fixedly and airtightly connected. Specifically, the outer circumferential surface of the threaded connection part 31 can be provided with a mounting outer hexagon 14, and the mounting outer hexagon 14 is fastened and installed by rotating.

[0026] The movable pipe inside the sampling device body 4 includes a first movable pipe 161 and a second movable pipe 162 connected in sequence, the inner diameter of the first movable pipe 161 is larger than that of the second movable pipe 162, so that a step surface is formed at the transition between the two. The first movable pipe 161 is connected to the corresponding movable pipe opening of the electromagnet 2, and the second movable pipe 162 is connected to the corresponding movable pipe opening of the metal film 11. The inner diameter of the first movable pipe 161 is adapted to the maximum outer diameter of the radial protrusion 71, so that the radial outer side of the radial protrusion 71 is in airtight connection with the inner wall of the first movable pipe 161. A radial boss 33 is formed inside the opening 32 in the packaging cover plate 3, and the opening 32 is formed inside the radial boss 33. The diameter of the opening 32 is smaller than the inner diameter of the first movable pipe 161 and also smaller than the diameter of the radial protrusion 71. The opening 32 provides a passage for the push rod 5 to pass through when the electromagnet is energized, pushing the ejector pin 8 to pierce the metal film 11.

[0027] A second O-ring groove 13 is provided on the end face of the radial boss 33 away from the electromagnet 2, and a rubber O-ring is arranged in the groove to further strengthen the sealing effect. When the metal film gas sampling device is working, the radial protrusion 71 moves to the left limit position in the direction close to the electromagnet 2 (away from the metal film 11) and abuts against the end face of the radial boss 33; when the radial protrusion 71 moves to the right limit position in the direction close to the metal film 11, it abuts against the step surface at the transition between the first movable pipe 161 and the second movable pipe 162. The rubber O-ring in the second O-ring groove 13 prevents the gas in the first movable pipe 161 from leaking into the opening 32, and the gas inside the packaging shell 1 also cannot flow into the first movable pipe 161 through the opening 32 in the opposite direction, thereby polluting the sampling gas.

[0028] The sampling device body 4 also includes a sampling branch 17 that communicates with the second movable pipe 162. The sampling branch 17 is inclined at an angle less than 90 degrees to the second movable pipe 162, and is inclined towards the direction close to the first end of the sampling device body 4. The sampling branch 17 has a sampling section 171, the pipe wall of the sampling section 171 is expanded radially to form a sampling chamber 18 inside for storing the sampling gas, and a normally closed outlet 19 is provided on the pipe wall of the sampling section 171. When the sampling is completed, the outlet 19 can be connected to an external pipeline, at which time the outlet 19 is opened to discharge the sampling gas for determination of the gas composition.

[0029] In use, the metal film gas sampling device is arranged in an external sealed container, and an external thread 20 can be provided on the outer circumferential surface of the second section of the sampling device body 4, which is fastened to the external sealed container, and the metal film 11 is pressed against the sealing surface of the device and the external sealed container, forming an initial isolation and sealing structure inside the device before sampling.

[0030] The working principle of the metal film gas sampling device is described below in terms of the initial state before sampling and the action state during and after sampling.

[0031] (I) Before sampling (initial state) Before sampling starts, the device is in a standby sealed state. At this time, the thimble assembly (including the thimble connecting piece 7 and the thimble 8) is located at the initial position on the left side close to the electromagnet 2, the tip of the thimble 8 maintains a preset distance from the metal film 11, and the metal film 11 is not punctured. The radially protruding part 71 towards the end face of the electromagnet 2 and the rubber O-ring in the second O-ring groove 13 form a tight fit, the electromagnet 2 does not receive an external electric control signal, the coil 6 does not generate an electromagnetic force, at this time, the tightness between the radially protruding part 71 and the rubber O-ring is provided by the spring of the electromagnet, and the spring force is directed away from the metal film 11. In this state, the complete metal film 11 is tightly attached to the sealing surface of the external sealed container, effectively blocking the communication between the high-temperature and high-pressure gas in the cylinder and the inside of the device, laying a foundation for subsequent precise sampling.

[0032] (II) During sampling (puncture and gas introduction) When instantaneous sampling is needed, an external 24V electric control signal is transmitted to the electromagnet 2, and the coil 6 generates an electromagnetic thrust after being energized. Under the action of the electromagnetic thrust, the push rod 5 drives the thimble connecting piece 7 and the thimble 8 to move synchronously to the right, and the tip of the thimble 8 gradually approaches and punctures the metal film 11 to form a sampling gas inlet channel. After the metal film 11 is damaged, the high-temperature and high-pressure gas in the external sealed container cylinder enters the second movable pipeline 162 through the channel, is guided to the sampling branch 17, and then is smoothly introduced into the sampling chamber 18 by the sampling branch 17, completing the collection of instantaneous gas. At this time, the thimble assembly remains in the right limit position, and the thimble 8 is still at the damaged place of the metal film 11, ensuring that the gas flow channel remains unobstructed and ensuring that the sampling gas enters the sampling chamber 18 smoothly.

[0033] (III) After sampling (sealing and gas temporary storage) After the gas collection is completed, the coil 6 is powered off, and the electromagnetic thrust disappears. Due to the high-pressure state maintained in the outer sealed container cylinder, the high-pressure gas acts on the right end face of the needle connecting piece 7, generating a leftward thrust, pushing the needle assembly as a whole to reset to the left, until the right tapered surface of the needle connecting piece 7 is tightly pressed against the rubber O-ring in the second O-ring groove 13. This pressing action forms a reliable high-pressure sealing structure, blocking the path of gas leakage from the opening 32 to the inside of the packaging shell 1, thereby physically separating the electromagnet 2 in the packaging shell 1 from the high-temperature and high-pressure gas in the cylinder, ensuring the stability of the device operation. The collected gas is contained in the sampling chamber 18, forming a temporary gas storage structure, which can control the gas reaction in the external sealed container to stop and prevent new gas from entering the sampling chamber 18 to contaminate the sampling gas. Subsequently, the sampling gas can be guided out through the outlet 19 to connect to the detection equipment for composition determination and analysis.

[0034] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0035] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

Claims

1. A metal membrane gas sampling device, characterized in that, It includes an electromagnet (2), a pin assembly, a sampling device body (4), and a metal membrane (11). The sampling device body (4) has an internal movable pipe running through both ends. The electromagnet (2) is airtightly connected to the first end of the sampling device body (4) and aligned with the corresponding opening of the movable pipe at that end. The metal film (11) covers the opening of the movable pipe at the second end of the sampling device body (4). The electromagnet (2) includes a push rod (5) and a coil (6). The coil (6) is used to drive the push rod (5) to move axially. The end of the push rod (5) is fixedly connected to the ejector assembly. The ejector assembly is coaxial with the movable pipe and can reciprocate within the movable pipe. The main body (4) of the sampling device is also provided with a sampling branch (17) connected to the movable pipeline, and a sampling chamber (18) for storing the sampling gas is provided on the sampling branch (17).

2. The metal membrane gas sampling device as described in claim 1, characterized in that, The movable pipe includes a first movable pipe (161) and a second movable pipe (162) connected end to end. The inner diameter of the first movable pipe (161) is larger than the inner diameter of the second movable pipe (162), and a step surface is formed at the transition between the two. The first active pipe (161) is located at the first end near the main body (4) of the sampling device, and the second active pipe (162) is located at the second end near the main body (4) of the sampling device. The sampling branch (17) is connected to the second active pipe (162).

3. The metal membrane gas sampling device as described in claim 2, characterized in that, The ejector assembly includes an ejector connector (7) and an ejector (8); The first end of the ejector pin connector (7) is provided with a radial protrusion (71). The maximum radial dimension of the radial protrusion (71) is adapted to the inner diameter of the first movable pipe (161), so that the radial outer side of the radial protrusion (71) forms an airtight connection with the inner wall of the first movable pipe (161). The radial protrusion (71) is fixedly connected to the tail end of the ejector pin (8); The radial dimension of the second end of the ejector pin connector (7) is smaller than that of the radial protrusion (71), and it is fixedly connected to the end of the push rod (5).

4. The metal membrane gas sampling device as described in claim 1, characterized in that, The electromagnet (2) also includes an encapsulation cover plate (3), one side of which is fixedly connected to the coil (6), and the other side is fastened to the first end of the sampling device body (4); The encapsulation cover (3) is annular, and a radial boss (33) is provided on the radial inner side of the encapsulation cover (3). The radial boss (33) surrounds the opening (32) through which the push rod (5) passes. The radial boss (33) has a second O-ring groove (13) on the end face away from the electromagnet (2). A rubber O-ring is arranged in the second O-ring groove (13). After the gas sampling is completed, the high-pressure gas entering the first active pipe (161) from the damaged part of the metal membrane (11) pushes the pin connector (7) to move to the position furthest away from the metal membrane (11), so that the end face of the radial protrusion (71) away from the metal membrane (11) is pressed tightly against the rubber O-ring in the second O-ring groove (13) to form an airtight connection.

5. The metal membrane gas sampling device as described in claim 1, characterized in that, The electromagnet (2) also includes a housing (1), which is fastened to the side of the housing (3) connected to the coil (6); The outer edge of the connection surface between the encapsulation cover plate (3) and the encapsulation shell (1) is provided with a first O-ring groove (12), and a rubber O-ring is provided in the groove for sealing.

6. The metal membrane gas sampling device as described in claim 1, characterized in that, The outer circumferential surface of the second end of the sampling device body (4) is provided with an external thread (20) for fastening to the external sealed container. The metal membrane (11) is pressed between the sampling device body (4) and the sealing surface of the external sealed container.

7. The metal membrane gas sampling device as described in claim 1, characterized in that, The angle between the sampling branch (17) and the second active pipe (162) is less than 90 degrees, and the sampling branch (17) is inclined toward the first end of the sampling device body (4).

8. The metal membrane gas sampling device as described in claim 1, characterized in that, The sampling branch (17) includes a sampling section (171), the wall of which expands radially to form the sampling chamber (18).

9. The metal membrane gas sampling device as described in claim 1, characterized in that, The sampling chamber (18) is provided with an outlet (19) for venting gas. The outlet (19) is normally closed. After sampling is completed, the outlet (19) can be connected to an external pipeline and the sampling gas can be vented.

10. The metal membrane gas sampling device as described in claim 3, characterized in that, The second end of the ejector pin connector (7) is fixedly connected to the end of the push rod (5) by an embedded fixing screw; The radial protrusion (71) has a recess on the side away from the electromagnet (2). The recess has an opening and a threaded hole (10) is provided inside the recess. An embedded fixing screw is provided in the threaded hole (10). The tail end of the ejector pin (8) is inserted into the recess. The ejector pin (8) is fixedly connected to the ejector pin connector (7) by tightening the embedded fixing screw. The radial protrusion (71) is frustum-shaped, and the diameter of the end of its outer circumference away from the metal film (11) is larger than that of the other end.

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