A novel sample collection tube and its usage method

Abstract

The application discloses a novel sample sampling tube, comprising a sample tube and an automatic thermal desorption instrument, and further comprising: a sealing head arranged at both ends of the sample tube and in sealing connection with the sample tube; a sample feeding needle connected with a detection end of the automatic thermal desorption instrument; a sealing structure arranged in the interior of the sealing head and used for sealing the sealing head and cooperating with the sample feeding needle; and an air pressure sensor fixed in the interior of the automatic thermal desorption instrument and connected with the sample feeding needle, and further electrically connected with a single-chip microcomputer system and a control panel. The novel sample sampling tube and the using method thereof are convenient to assemble and use, can be more convenient and stable during detection, can be convenient to replace the sealing gasket while guaranteeing the service life of the sealing gasket, reduce the maintenance cost, and can further avoid the air leakage while guaranteeing the sealing property by performing real-time air leakage detection.

Description

Technical Field

[0001] This invention relates to the field of TVOC sample sampling tube technology, specifically to a novel sample sampling tube and its usage method. Background Technology

[0002] Automated thermal desorption is a pretreatment process for TVOC samples. It typically uses an automated thermal desorption / desorption instrument in conjunction with TVOC sample collection tubes. These TVOC sample collection tubes, also known simply as TVOC sampling tubes or sample collection tubes, are used to collect airborne samples with concentrations in the range of 0.5 mg / m³. 3 ~100mg / m 3 Pipe fittings with total volatile organic compounds (TVOC).

[0003] The following are the current application methods and problems of sample collection tubes produced on the market in fully automated thermal desorption (thermal desorption):

[0004] 1. Using sealing caps on both ends of the sampling tube, the sealing caps are removed by a robotic arm during the first desorption, and then the gas path mechanism is used to seal and purge the two ends. This method has a relatively complex motion mechanism, cannot guarantee reliability, and is costly.

[0005] 2. Use a special sealing head to cover both ends of the sampling tube. The sealing head is sealed to the outside through the sealing gasket. During the first desorption, the needle is inserted into the sealing gasket to purge air. After purging, the needle is pulled out. After inserting and removing the needle multiple times, the sealing gasket is prone to leakage, and the debris of the sealing gasket will enter the needle, causing the needle to become blocked.

[0006] 3. Use a special sealing head to cover both ends of the sampling tube. The sealing head uses a spring and a waist drum ring for sealing inside. An additional sealing rubber gasket is needed on the outside of the sealing head to seal with the injection pin. The sealing rubber gasket must be embedded in the injection pin. The injection pin is a moving part installed inside the machine. Therefore, when the rubber gasket ages and cracks, it will not be able to seal effectively, resulting in air leakage and causing problems with instrument analysis. The rubber gasket is not easy to replace. It is necessary to remove the machine cover and the moving mechanism to replace it, which will result in a lot of work and cost for the later maintenance of the instrument. Summary of the Invention

[0007] Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention provides a novel sample collection tube and its usage method, aiming to solve the aforementioned problems.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A novel sample collection tube includes a sample tube and an automated thermal desorption / extraction apparatus, and further includes:

[0011] A sealing head is located at both ends of the sample tube and is sealed to the sample tube.

[0012] The sample injection pin is connected to the detection end of the automatic thermal desorption / desorption instrument;

[0013] A sealing structure is located inside the sealing head to seal the sealing head and cooperates with the injection pin.

[0014] The pressure sensor is fixed inside the automatic thermal desorption instrument and connected to the sample injection pin. It is also electrically connected to the microcontroller system and control panel.

[0015] Preferably, the sealing head includes:

[0016] The outer shell is cylindrical with a protruding center and threads at both ends;

[0017] A insertion hole, located at one end of the outer casing, is used to insert a sample tube;

[0018] A sealing ring is located inside the insertion hole;

[0019] A movable sleeve, which is threadedly connected to one end of the outer casing;

[0020] The limiting sleeve is threadedly connected to the other end of the outer shell;

[0021] A sealing gasket, located inside the limiting sleeve and at the end of the housing;

[0022] The guide hole is a tapered hole and is located at the end of the limiting sleeve;

[0023] A sealing structure is located inside the housing and extends through the sealing plug into the interior of the guide hole.

[0024] Preferably, the diameters of the protruding portions in the middle of the outer shells of the two sealing heads are different, and both are larger than the diameters of the movable sleeve and the limiting sleeve.

[0025] Preferably, the sealing structure includes:

[0026] The movable block is slidably connected to the inside of the outer casing;

[0027] The guide post is fixedly connected to one end of the movable block;

[0028] A stabilizing spring, which is sleeved on the outside of the guide post;

[0029] A fixed post, which is fixed to the other end of the movable block, extends through the sealing gasket into the interior of the guide hole;

[0030] The air intake is located at the top of the fixed post;

[0031] Multiple connection holes are provided on the side of the fixed post and communicate with the bottom of the air intake.

[0032] Preferably, the side of the movable block has a groove for gas to pass through.

[0033] Preferably, a guide block is fixed at the bottom of the injection pin, and the guide block is adapted to the fixed column.

[0034] A method for using a novel sample collection tube includes the following steps:

[0035] Step 1: Install the sample tube to be tested into the test position of the automatic thermal desorption desorber, and then move the sample injection pin into the guide hole.

[0036] Step 2: The injection pin is pressed down, causing the fixed column to move down, so that the connection hole moves away from the sealing gasket and enters the interior of the shell. At the same time, the injection pin presses against the sealing gasket to complete the seal.

[0037] Step 3: The automatic thermal desorption / desorption instrument operates. The gas to be detected between the automatic thermal desorption / desorption instrument and the sample tube flows through the injection pin, air inlet, connection hole, outer shell, and plug-in hole.

[0038] Meanwhile, the injection pin is connected to the pressure sensor, which detects the internal pressure data P in real time.

[0039] Step 4: Detect the air pressure value P detected in the nth second. n The data is transmitted to the microcontroller system to calculate whether there is a leak.

[0040] Step 5: Determine there is no air pressure leak, then continue working;

[0041] If a pressure leak is detected, stop operation and issue an alarm.

[0042] Preferably, a control panel is used to display the working status and leakage situation, while the test data is stored in its internal storage structure.

[0043] Preferably, the specific process for calculating whether a leak has occurred includes:

[0044] Step 1: Obtain the air pressure value P n ;

[0045] Step 2: Calculation

[0046] Where P0 is the rated air pressure, P m The maximum pressure reduction ratio is calculated. When P < 0, the system operates normally. When P ≥ 0, it indicates a leak and triggers an alarm.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] This invention provides a novel sample tube and its usage method, which effectively solves the problems of sample tube loading and sealing in fully automated thermal desorption applications. Similar to a quick connector, simply inserting the sample tube seals the sampled tube. During desorption, a dedicated injection pin allows for purging with air, ensuring a highly reliable seal. After purging, the injection pin is withdrawn, and the dedicated sealing head restores the seal. This allows for convenient and quick sample tube installation, excellent sealing performance, and longevity. Furthermore, the mechanical design is simple, improving reliability and reducing costs.

[0049] Meanwhile, this invention not only solves the air leakage problem but also has a leak detection alarm function. The silicone rubber sealing gasket in the sample tube sealing cap is also a consumable. This invention integrates the silicone rubber sealing gasket into the sample tube sealing cap. When the sealing ring ages and the sealing effect is poor, the user can replace the silicone rubber sealing gasket in the sample tube sealing cap by himself, eliminating the need to replace the sealing gasket at the sample injection pin in the equipment, which greatly reduces the product maintenance cost. In addition, it can be used in conjunction with this new sample sampling tube to detect air leakage, monitor the air leakage situation in real time, prevent leakage in advance, and eliminate the need for users to return to the site for resampling, which greatly reduces the labor cost. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of a novel sample collection tube according to the present invention;

[0051] Figure 2 This is an enlarged schematic diagram of the internal structure of the sealing head described in this invention;

[0052] Figure 3 This is an enlarged schematic diagram of the structure after the sealing head and the injection pin of the present invention are connected;

[0053] Figure 4 This is an enlarged schematic diagram of the connection between the sealing head and the injection pin described in this invention;

[0054] Figure 5 This is a flowchart illustrating the use of a novel sample collection tube as described in this invention.

[0055] In the figure: 10 Sample tube, 20 Sealing head, 21 Outer shell, 22 Insertion hole, 23 Sealing ring, 24 Movable sleeve, 25 Limiting sleeve, 26 Sealing gasket, 27 Guide hole, 30 Sealing structure, 31 Movable block, 32 Guide post, 33 Stabilizing spring, 34 Fixed post, 35 Air inlet, 36 Connection hole, 40 Sample injection pin, 41 Guide block, 50 Automatic thermal desorption instrument, 60 Pressure sensor. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0057] Please see Figure 1 A novel sample sampling tube is disclosed, comprising a sample tube 10 and an automatic thermal desorption / desorption apparatus 50. The automatic thermal desorption / desorption apparatus 50 is a conventional automatic thermal desorption / desorption apparatus. The sample tube 10 is a tube for storing the gas to be measured. It also includes sealing heads 20, which are disposed at both ends of the sample tube 10 and are sealed to the sample tube 10. The sample tube 10 and the sealing heads 20 at both ends combine to form the novel sample sampling tube of this application. An injection pin 40 is connected to the detection end of the automatic thermal desorption / desorption apparatus 50. The automatic thermal desorption / desorption apparatus 50 is the detection instrument for the novel sample sampling tube, and the injection pin 40 is a matching pin used in conjunction with the novel sample sampling tube of this application, and is an indispensable part of the novel sample sampling tube of this application.

[0058] Specifically, in this embodiment, please refer to Figure 1 , 2 3 and 4, the sealing head 20 consists of a shell 21, a insertion hole 22, a sealing ring 23, a movable sleeve 24, a limiting sleeve 25, a sealing gasket 26, a guide hole 27, and a sealing structure 30. The shell 21 is cylindrical and stepped, protruding in the middle, and has threads at both ends to mate with the sealing ring 23 and the movable sleeve 24. An insertion hole 22 is provided at one end of the shell 21, through which the sample tube 10 can pass and enter the interior of the insertion hole 22. The end face of the movable sleeve 24 has a hole to mate with the sample tube 10. To ensure a seal between the sample tube 10 and the shell 21, a sealing ring 23 is provided at the connection between the sample tube 10, the shell 21, and the movable sleeve 24 (e.g., ...). Figure 2 The sealing ring 23 is located at the bottom of the insertion hole 22. To further ensure the seal, the sample tube 10 is press-fitted with the sealing ring 23.

[0059] A sealing gasket 26, made of silicone rubber, is provided at the end of the outer shell 21 away from the insertion hole 22. One end of the outer shell 21 abuts against the sealing gasket 26, and the limiting sleeve 25 is tightly attached to the sealing gasket 26. A sealing structure 30 is provided inside the outer shell 21 to cooperate with the injection pin 40. A guide hole 27, which is a tapered hole, is provided on the end face of the limiting sleeve 25 to cooperate with the insertion of the injection pin 40. When the sealing gasket 26 needs to be replaced, the limiting sleeve 25 can be unscrewed for replacement. It is no longer necessary to replace the sealing gasket inside the injection pin, making the operation simpler and more practical, and reducing maintenance costs.

[0060] Specifically, the sealing structure 30 proposed in this embodiment consists of a movable block 31, a guide post 32, a stabilizing spring 33, a fixed post 34, an air inlet 35, and multiple connecting holes 36. The movable block 31 is slidably connected to the inside of the outer casing 21, with one end fixed to the guide post 32 and the other end fixed to the fixed post 34. The fixed post extends through the sealing gasket 26 into the interior of the guide hole 27, and the fixed post 34 is in close contact with the sealing gasket 26. The air inlet 35 is located at the top of the fixed post 34, and the connecting holes 36 are located on the side of the fixed post 34. The sealing gasket 26 is located inside and communicates with the bottom of the air inlet 35. The stabilizing spring 33 is sleeved on the outside of the guide post 32. To ensure that the gas can enter the injection pin 40 from the inside of the sample tube 10 during the test without being unexpectedly blocked, a groove is opened on the side of the movable block 31. At the same time, a through hole is opened inside the outer shell 21. Thus, during the test, the injection pin 40 and the sample tube 10 can communicate through the air inlet 35, the connecting hole 36, the groove, the through hole, and the insertion hole 22. The specific test process is as follows.

[0061] When not in use, the movable block 31 is tightly pressed against the sealing gasket 26, sealing the connection. The fixed post 34 is also in close contact with the sealing gasket 26, sealing the connection and effectively preventing gas leakage. During testing, the injection pin 40 moves the fixed post 34 until it presses against the sealing gasket 26, sealing the connection. At this time, the connection hole 36 moves away from the sealing gasket 26 and enters the interior of the outer shell 21, where it connects with the insertion hole 22. Gas can then pass through the injection pin 40 (existing technology) and communicate with the interior of the new sample sampling tube through the air inlet 35 and the connection hole 36 to complete gas flow. Conversely, when no longer in use, the restoring force of the stabilizing spring 33 can push the movable block 31 and the fixed post 34 back to their initial positions, simplifying operation, reducing mechanical damage to the sealing gasket 26, reducing gas leakage, and ensuring a tight seal.

[0062] To ensure that the novel sample collection tube of this application can be properly installed on the detection stage of the existing automatic thermal desorption instrument, the diameters of the protruding parts in the middle of the outer shells 21 of the two sealing heads 20 are different, and both are larger than the diameters of the movable sleeve 24 and the limiting sleeve 25.

[0063] Please see Figure 3 and 4 To further prevent leakage and ensure gas flow at the injection pin 40, a guide block 41 is fixed at the bottom of the injection pin 40, and a groove is provided at the top of the fixing post 34, which is adapted to the guide block 41.

[0064] In another embodiment, please refer to Figure 3To prevent gas leakage during detection and ensure the detection results, a pressure sensor 60 is fixed inside the automatic thermal desorption / desorption instrument 50. The detection end of the pressure sensor 60 is connected to the sample injection pin 40, and the power and signal terminals are electrically connected to the microcontroller system and control panel. The specific connection method is the most common connection method in existing electrical systems, which can achieve the effect of stable connection and stable signal transmission. The details will not be elaborated further.

[0065] In this embodiment, please refer to Figure 5 This application also includes a method for using a novel sample collection tube, specifically comprising the following steps:

[0066] Step 1: Install the sample tube to be tested into the test position of the automatic thermal desorption desorption instrument 50, and then move the sample injection pin 40 to the guide hole 27 and enter the interior of the guide hole 27.

[0067] Step 2: The injection pin 40 is pressed down, which moves the fixing column 34 downward, so that the connecting hole 36 moves away from the sealing gasket 26 and enters the interior of the outer shell 21. At the same time, the injection pin 40 presses against the sealing gasket 26 to complete the seal.

[0068] Step 3: The automatic thermal desorption and desorption instrument 50 is in operation. The gas to be detected between the automatic thermal desorption and desorption instrument 50 and the sample tube 10 flows through the injection pin 40, the air inlet 35, the connection hole 36, the outer shell 21 and the insertion hole 22.

[0069] Meanwhile, the injection pin 40 is connected to the pressure sensor 60, and the pressure sensor 60 detects the internal pressure data P in real time.

[0070] Step 4: Detect the air pressure value P detected in the nth second. n The data is transmitted to the microcontroller system to calculate whether there is a leak.

[0071] Step 5: Determine there is no air pressure leak, then continue working;

[0072] If a pressure leak is detected, stop operation and issue an alarm.

[0073] The control panel displays the working status and leakage situation, while the internal storage structure stores the test data.

[0074] The specific process for calculating whether a leak has occurred includes:

[0075] Step 1: Obtain the air pressure value P n ;

[0076] Step 2: Calculation

[0077] Where P0 is the rated air pressure, P mThe maximum pressure reduction ratio is calculated. When P < 0, the system operates normally. When P ≥ 0, it indicates a leak and triggers an alarm.

[0078] By using the above method in conjunction with the new sample collection tube for leak detection, real-time monitoring of leaks can be achieved, allowing for early prevention and eliminating the need for users to return to the site for resampling, thus significantly reducing labor costs.

[0079] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel sample collection tube, comprising a sample tube and an automated thermal desorption / extraction apparatus, characterized in that, Also includes: A sealing head, located at both ends of a sample tube and sealingly connected to it, comprises: a cylindrical outer shell with threads at both ends; a limiting sleeve threaded to one end of the outer shell; a sealing gasket located inside the limiting sleeve and at the end of the outer shell; a guide hole at the end of the limiting sleeve; an injection pin connected to the detection end of an automatic thermal desorption / desorption apparatus; a sealing structure located inside the outer shell for sealing the sealing head and cooperating with the injection pin; and a pressure sensor fixed inside the automatic thermal desorption / desorption apparatus and connected to the injection pin, while also electrically connected to a microcontroller system and a control panel. The outer shell protrudes in the middle; the sealing head further includes: an insertion hole, which is opened at one end of the outer shell for inserting a sample tube; a sealing ring, which is disposed inside the insertion hole; a movable sleeve, which is threaded to one end of the outer shell; the guide hole is a tapered hole; the sealing structure extends through the sealing plug to the inside of the guide hole; a sealing gasket is provided at the end of the outer shell away from the insertion hole, the sealing gasket is a silicone fluororubber sealing gasket, one end of the outer shell abuts against the sealing gasket, and the limiting sleeve is tightly attached to the sealing gasket; The sealing structure includes: a movable block slidably connected to the inside of the housing, with a groove on its side for gas passage; a guide post fixedly connected to one end of the movable block; a stabilizing spring sleeved on the outside of the guide post; a fixed post fixed to the other end of the movable block and extending through the sealing gasket into the inside of the guide hole; an air inlet at the top of the fixed post; and multiple connecting holes on the side of the fixed post, communicating with the bottom of the air inlet. When not in use, the movable block is tightly against the sealing gasket, sealing the connection, and the fixed post is also in close contact with the sealing gasket, sealing the connection and effectively preventing gas leakage. During testing, the injection pin moves the fixed post against the sealing gasket until it seals the connection.

2. The novel sample collection tube according to claim 1, characterized in that, The diameters of the protruding portions in the middle of the outer shells of the two sealing heads are different, and both are larger than the diameters of the movable sleeve and the limiting sleeve.

3. The novel sample collection tube according to claim 1, characterized in that, The bottom of the injection pin is fixed with a guide block, which is adapted to the fixed column.

4. A method for using a novel sample collection tube, characterized in that, A novel sample sampling tube based on any one of claims 1-3 comprises the following steps: Step 1: Install the sample sampling tube to be tested into the detection position of the automatic thermal desorption / desorption instrument, and then move the injection pin to the guide hole and enter the interior of the guide hole; Step 2: Press down the injection pin to drive the fixing column to move down, so that the connection hole moves away from the sealing gasket and enters the interior of the outer shell, while the injection pin abuts against the sealing gasket to complete the seal; Step 3: The automatic thermal desorption / desorption instrument operates, and the gas to be detected between the automatic thermal desorption / desorption instrument and the sample tube flows through the injection pin, the air inlet, the connection hole, the outer shell, and the insertion hole; at the same time, the injection pin is connected to the pressure sensor, and the pressure sensor detects the internal pressure data P in real time; Step 4: Detect the pressure value detected at the nth second. The data is transmitted to the microcontroller system to calculate whether there is a leak; Step 5: If no air pressure leak is detected, continue working; if an air pressure leak is detected, stop working and issue an alarm.

5. The method of using the novel sample collection tube according to claim 4, characterized in that, The control panel displays the working status and leakage situation, while its internal storage structure stores the test data.

6. The method of using the novel sample collection tube according to claim 4, characterized in that, The specific process for calculating whether there is a leak includes: Step 1, obtaining the air pressure value. ; Step 2: Calculation ; in, Rated air pressure, The maximum pressure reduction ratio; when P < 0, normal operation occurs; when... If this is the case, it indicates a leak and triggers an alarm.

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