True density measuring device

Abstract

The present application relates to the technical field of measurement, and particularly provides a true density detection device, which aims to solve the problems of high cost and many leakage points of a true density instrument for realizing positive and reverse air intake. To this end, the present application provides a true density detection device, which comprises an air path module, the air path module comprising a buffer bin, a sample bin and an expansion bin, the buffer bin being in communication with an air inlet and an air outlet of the air path module at the same time, the volume of the buffer bin being smaller than the volume of the sample bin and the expansion bin; the sample bin and the expansion bin are in communication with the buffer bin, and the sample bin and the expansion bin can only be in communication through the buffer bin. Through the above setting, in the case of positive air intake or reverse air intake, the air intake can first enter and fill the buffer bin, and then enter the sample bin. Since the volume of the buffer bin is very small, the pressure difference between the two bins will be quickly balanced, which can effectively avoid blowing up the powdery sample, and there is no need to set a proportional valve, which is conducive to reducing the cost, simplifying the pipeline setting and reducing the leakage points.

Description

True density testing device Technical Field

[0001] This invention relates to the field of measurement technology, and specifically provides a true density detection device. Background Technology

[0002] A true density meter is a scientific instrument that precisely measures the volume of a material based on the gas displacement method. Its core principle involves infiltrating small-molecule inert gases, such as helium, into the material's fine pores, using Boyle's law to accurately calculate the sample's true volume, and simultaneously determining the sample's mass using external instruments, thus obtaining its true density. However, when measuring the true density of lightweight, powdery samples, using a forward-inlet method can cause high-pressure gas to directly rush into the sample chamber during the inlet phase. In this case, the positive pressure difference can lead to sample escape. Furthermore, during the expansion phase, a maximum negative pressure difference exists between the sample chamber and the expansion chamber, the value of which is the difference between the target pressure and atmospheric pressure, further causing sample escape and affecting the accuracy of the measurement results.

[0003] Therefore, true density analyzers are equipped with a reverse gas inlet function to reduce sample fly-off. In this function, the true density analyzer first fills the expansion chamber with gas, bringing it to the target pressure. Then, a proportional valve expands the gas in the expansion chamber to the partial pressure of the sample chamber. With reverse gas inlet, a negative pressure difference exists only during the exhaust phase, and its value is approximately 0.3 to 0.7 times the maximum negative pressure difference under forward gas inlet, thus preventing powder fly-off. However, to accommodate the reverse gas inlet function, true density analyzers typically require at least two proportional valves and very complex piping, resulting in high instrument costs, numerous potential leak points, and significant difficulty in identifying leaks. Summary of the Invention

[0004] This application aims to solve the aforementioned technical problems, namely, to address the issues of high cost and numerous leakage points in existing true density meters for achieving forward and reverse air intake.

[0005] This application provides a true density testing device, which includes a gas path module. The gas path module includes a buffer chamber, a sample chamber, and an expansion chamber. The buffer chamber is connected to both the air inlet and the air outlet of the gas path module. The volume of the buffer chamber is smaller than the volumes of the sample chamber and the expansion chamber.

[0006] Both the sample compartment and the expansion compartment are connected to the buffer compartment, and the sample compartment and the expansion compartment can only be connected through the buffer compartment.

[0007] With the above technical solution, the true density detection device can first fill the buffer chamber with gas, regardless of whether the gas is introduced in the forward or reverse direction. Then, the valve is opened to allow the gas to enter the sample chamber. Since the buffer chamber is very small, the pressure difference between the buffer chamber and the corresponding chamber will be balanced in a very short time, which can effectively prevent the powdery sample from being blown up. In addition, when the sample chamber and the expansion chamber are connected, the buffer chamber can replace the proportional valve, which helps to reduce the cost of the instrument, simplify the pipeline setup, and reduce the number of leakage points.

[0008] In the preferred embodiment of the above-mentioned true density detection device, the volume of the buffer chamber is set to be less than or equal to 2 ml.

[0009] In the preferred embodiment of the above true density detection device, the gas path module includes an air inlet channel, an air outlet channel, and a buffer channel. One end of the air inlet channel is provided with the air inlet, one end of the air outlet channel is provided with the air outlet, and the buffer channel is connected to the air inlet channel and the air outlet channel respectively.

[0010] The sample chamber is connected to any one of the air inlet channel, the exhaust channel, or the buffer channel via a sample valve, and the expansion chamber is connected to any one of the air inlet channel, the exhaust channel, or the buffer channel via an expansion valve;

[0011] The space connecting the air intake channel, the exhaust channel, the buffer channel, the sample valve, and the expansion valve forms the buffer chamber.

[0012] In the preferred embodiment of the above-mentioned true density testing device, the diameters of the air intake channel, the exhaust channel, and the buffer channel are all set to be less than 2 mm.

[0013] In the preferred embodiment of the above-mentioned true density detection device, the expansion chamber is configured as a plurality of chambers, and the plurality of expansion chambers have different volumes.

[0014] In the preferred embodiment of the above-mentioned true density detection device, the ratio of the volume of the buffer chamber to the volume of the smallest expansion chamber is 1:5 to 1:10.

[0015] In the preferred embodiment of the above-mentioned true density detection device, the true density detection device includes a sample cup assembly, which includes a cup body and a lid. The cup body is used to contain a sample, and the lid is placed on the cup body. The lid is provided with a vent hole and is used to connect with the measurement interface of the sample chamber. The lid is also capable of filtering the sample in the airflow.

[0016] In the preferred embodiment of the above-mentioned true density testing device, the cover includes a main body, a filter element, and a sealing ring. A first groove is formed in the middle of the upper surface of the main body, and a vent hole is formed at the bottom of the first groove. The filter element is disposed in the first groove and covers the vent hole. The sealing ring is used to achieve a seal between the main body and the cup body.

[0017] In the preferred embodiment of the above-mentioned true density testing device, a second groove is provided on the periphery of the main body, and the sealing ring is set as an O-ring, which is disposed in the second groove.

[0018] In the preferred embodiment of the above-mentioned true density testing device, the filter element is set as any one of a sieve plate, a sintered filter, a filter element, and a filter plate; and / or the material of the cup body and / or the main body is set as any one of aluminum, copper, stainless steel, and titanium. Attached Figure Description

[0019] The true density testing apparatus of this application will now be described with reference to the accompanying drawings. In the drawings:

[0020] Figure 1 is an overall structural diagram of the true density testing device of this application;

[0021] Figure 2 is an overall structural diagram of the gas path module of this application;

[0022] Figure 3 is an internal perspective view of the gas path module of this application;

[0023] Figure 4 is an overall structural diagram of the sample cup assembly of this application;

[0024] Figure 5 is a cross-sectional view of the sample cup assembly of this application;

[0025] Figure 6 is an overall structural diagram of the lid in the sample cup assembly of this application;

[0026] Figure 7 is a cross-sectional view of the lid in the sample cup assembly of this application.

[0027] List of reference numerals

[0028] 2. Gas path module; 21. Sample chamber; 22. Expansion chamber; 23. Inlet channel; 24. Exhaust channel; 25. Buffer channel; 26. Inlet valve; 27. Exhaust valve; 28. Sample valve; 29. ​​Expansion valve;

[0029] 9. Sample cup assembly; 91. Cup body; 92. Lid; 921. Vent hole; 922. Main body; 9221. First groove; 9222. Second groove; 923. Filter element; 924. Sealing ring. Detailed Implementation

[0030] Preferred embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application. For example, although two expansion compartments are provided in the drawings, this is not intended to limit the scope of protection of this application, and those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0031] It should be noted that in the description of this application, terms such as "center," "upper," "lower," "left," "right," "inner," and "outer," indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Additionally, in the description of this application, "a plurality of" refers to at least two.

[0032] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0033] As described in the background section, a true density meter is a scientific instrument that precisely measures the volume of a material based on the gas displacement method. Its core principle involves using an inert gas with a small molecular diameter, such as helium, to penetrate the material's fine pores. Boyle's law is then used to accurately calculate the sample's true volume, while an external instrument determines the sample's mass, thus yielding its true density. However, when measuring the true density of lightweight, powdery samples, using a forward-inlet method can cause high-pressure gas to directly rush into the sample chamber during the inlet phase. In this case, the positive pressure difference can lead to sample escape. Furthermore, during the expansion phase, a maximum negative pressure difference exists between the sample chamber and the expansion chamber, the value of which is the difference between the target pressure and atmospheric pressure. This further contributes to sample escape, affecting the accuracy of the measurement results.

[0034] Therefore, true density analyzers are equipped with a reverse gas inlet function to reduce sample fly-off. In this function, the true density analyzer first fills the expansion chamber with gas, bringing it to the target pressure. Then, a proportional valve expands the gas in the expansion chamber to the partial pressure of the sample chamber. With reverse gas inlet, a negative pressure difference exists only during the exhaust phase, and its value is approximately 0.3 to 0.7 times the maximum negative pressure difference under forward gas inlet, thus preventing powder fly-off. However, to accommodate the reverse gas inlet function, true density analyzers typically require at least two proportional valves and very complex piping, resulting in high instrument costs, numerous potential leak points, and significant difficulty in identifying leaks.

[0035] To address the issues of high cost and numerous leaks associated with existing true density meters that require both forward and reverse air intake, this application provides a true density testing device, including a gas path module. The gas path module comprises a buffer chamber, a sample chamber, and an expansion chamber. The buffer chamber is connected to both the air inlet and outlet of the gas path module, and its volume is smaller than that of the sample chamber and the expansion chamber. Both the sample chamber and the expansion chamber are connected to the buffer chamber, and the sample chamber and the expansion chamber can only be connected through the buffer chamber.

[0036] With the above technical solution, the true density detection device can first fill the buffer chamber with gas, regardless of whether the gas is introduced in the forward or reverse direction. Then, the valve is opened to allow the gas to enter the sample chamber. Since the buffer chamber is very small, the pressure difference between the buffer chamber and the corresponding chamber will be balanced in a very short time, which can effectively prevent the powdery sample from being blown up. In addition, when the sample chamber and the expansion chamber are connected, the buffer chamber can replace the proportional valve, which helps to reduce the cost of the instrument, simplify the pipeline setup, and reduce the number of leakage points.

[0037] The true density detection device of this application will now be described with reference to Figures 1 to 7. Figure 1 is an overall structural diagram of the true density detection device of this application; Figure 2 is an overall structural diagram of the gas path module of this application; Figure 3 is an internal perspective view of the gas path module of this application; Figure 4 is an overall structural diagram of the sample cup assembly of this application; Figure 5 is a cross-sectional view of the sample cup assembly of this application; Figure 6 is an overall structural diagram of the cover of the sample cup assembly of this application; and Figure 7 is a cross-sectional view of the cover of the sample cup assembly of this application.

[0038] As shown in Figures 1 to 7, in a preferred embodiment, the true density detection device includes a gas path module 2 and a sample cup assembly 9. The gas path module 2 includes a buffer chamber, a sample chamber 21, and an expansion chamber 22. The buffer chamber is connected to both the air inlet and outlet of the gas path module 2, and its volume is smaller than the volumes of the sample chamber 21 and the expansion chamber 22. Both the sample chamber 21 and the expansion chamber 22 are connected to the buffer chamber, and the sample chamber 21 and the expansion chamber 22 can only be connected through the buffer chamber.

[0039] Referring first to Figures 2 and 3, in this embodiment, the buffer chamber is constructed through the body of the gas path module 2. Specifically, the gas path module 2 includes an inlet channel 23, an exhaust channel 24, and a buffer channel 25. One end of the inlet channel 23 has an inlet port, and one end of the exhaust channel 24 has an exhaust port. The buffer channel 25 is connected to both the inlet channel 23 and the exhaust channel 24. The sample chamber 21 is connected to any one of the inlet channel 23, the exhaust channel 24, or the buffer channel 25 via a sample valve 28. The expansion chamber 22 is connected to any one of the inlet channel 23, the exhaust channel 24, or the buffer channel 25 via an expansion valve 29. The space connecting the inlet channel 23, the exhaust channel 24, the buffer channel 25, the sample valve 28, and the expansion valve 29 forms the buffer chamber. Multiple expansion chambers 22 are provided, and each expansion chamber 22 has a different volume.

[0040] In this embodiment, two expansion chambers 22 are provided, as shown in Figure 3. The larger expansion chamber 22 is connected to the air intake channel 23 through a corresponding expansion valve 29, and the smaller expansion chamber 22 is connected to the exhaust channel 24 through a corresponding expansion valve 29. The sample chamber 21 is connected to the exhaust channel 24 through a sample valve 28. Of course, the positions of the air intake channel 23 and the exhaust channel 24 are not fixed. Air can also enter through the exhaust channel 24 on the right side of the figure, in which case exhaust occurs through the air intake channel 23 on the left side, depending on the specific installation method of the device. Furthermore, in this embodiment, the volume of the buffer chamber is set to be less than or equal to 2 ml, the pipe diameters of the air intake channel 23, the exhaust channel 24, and the buffer channel 25 are set to be less than 2 mm, and the ratio of the volume of the buffer chamber to the volume of the smallest expansion chamber 22 is 1:5 to 1:10. Specifically, the volume of the buffer chamber is set to 2ml, the diameter of the air intake channel 23, the exhaust channel 24 and the buffer channel 25 are all set to 1.6mm, the volume of the smallest expansion chamber 22 is 10ml, and the ratio of the volume of the buffer chamber to its volume is 1:5.

[0041] Referring to Figures 4 to 7, the sample cup assembly 9 includes a cup body 91 and a lid 92. The cup body 91 is used to hold the sample, and the lid 92 covers the cup body 91. The lid 92 is provided with a vent hole 921. The lid 92 is used to connect with the measurement interface of the sample chamber 21, and the lid 92 can filter the sample in the airflow. The lid 92 includes a main body 922, a filter element 923, and a sealing ring 924. A first groove 9221 is formed in the middle of the upper surface of the main body 922. A vent hole 921 is formed at the bottom of the first groove 9221. The filter element 923 is disposed in the first groove 9221 and covers the vent hole 921. The sealing ring 924 is used to achieve a seal between the main body 922 and the cup body 91. A second groove 9222 is formed on the periphery of the main body 922. The sealing ring 924 is an O-ring and is disposed in the second groove 9222.

[0042] In this embodiment, the vent 921 is located at the center of the cover 92, the first groove 9221 is circular, and the filter element 923 is a sieve plate in the shape of a small disc. The shape of the first groove 9221 matches that of the filter element 923. The cup body 91 and the main body 922 of the cover 92 are made of aluminum. When assembling the cover 92, the filter element 923 is first placed in the first groove 9221 and gently squeezed to make the filter element 923 adhere to the bottom of the first groove 9221. At this time, the filter element 923 can cover the vent 921. Then, the sealing ring 924 is fitted into the second groove 9222. When it is necessary to remove the filter element 923, simply use a thin rod to push the filter element 923 out from the vent 921.

[0043] The following section first describes the detection process of the true density detection device of this application.

[0044] The detection process consists of four stages, which will be introduced first using forward air intake as an example. The first stage is the air intake stage, during which the following cycle is executed: intake valve 26 opens - intake valve 26 closes - sample valve 28 opens - sample valve 28 closes - pressure is measured. That is, the air intake method is pulse intake, and each intake first enters the buffer chamber, and then through the buffer chamber into the sample chamber 21. Until: pressure > target pressure - first specific parameter, sample valve 28 is opened and kept open, and the following cycle begins: intake valve 26 opens - intake valve 26 closes - pressure is measured. That is, the air intake method remains pulse intake, but at this time the buffer chamber and sample chamber 21 remain connected, and each intake directly enters the sample chamber 21 through the buffer chamber. Until: pressure ≥ target pressure, the pressure is allowed to balance, and the current pressure and temperature are read, then sample valve 28 is closed. It can be seen that at this time, intake valve 26, exhaust valve 27, sample valve 28, and expansion valve 29 are all in the closed state.

[0045] The second stage is the low-pressure reading stage. During this stage, the expansion valve 29 and exhaust valve 27 are opened, and the pressure is measured simultaneously. This means that the buffer chamber, expansion chamber 22, and the external environment or exhaust pipe are all connected at this time. The pressure is maintained until it is less than atmospheric pressure plus a second specific parameter. Then, exhaust valve 27 and expansion valve 29 are closed, and the pressure is allowed to equalize before the current pressure and temperature are read. It can be seen that at this time, inlet valve 26, exhaust valve 27, sample valve 28, and expansion valve 29 are all closed.

[0046] The third stage is the expansion stage, during which the following cycle is executed: sample valve 28 opens - sample valve 28 closes - expansion valve 29 opens - expansion valve 29 closes - pressure is measured. That is, the gas in sample chamber 21 enters expansion chamber 22 in a pulsed manner through the buffer chamber. This continues until: pressure < proportional coefficient × expected pressure + (1 - proportional coefficient) × inlet pressure. Then, sample valve 28 and expansion valve 29 are opened, pressure is allowed to balance, and the current pressure and temperature are read. Finally, expansion valve 29 is closed. The expected pressure is determined by the previous balance pressure. It can be seen that at this time, inlet valve 26, exhaust valve 27, and expansion valve 29 are all closed, while sample valve 28 is open.

[0047] The fourth stage is the exhaust stage, during which the following cycle is executed: sample valve 28 opens - sample valve 28 closes - exhaust valve 27 opens - exhaust valve 27 closes - pressure is measured until: pressure < atmospheric pressure + first specific parameter, then sample valve 28, expansion valve 29 and exhaust valve 27 are opened until pressure < atmospheric pressure + second specific parameter.

[0048] During reverse air intake, only the sample valve 28 and the expansion valve 29 in each stage need to be swapped, which will not be elaborated here. Furthermore, the method of determining the sample volume by measuring the pressure at each stage is also existing technology, and will not be elaborated here either. In addition, unlike existing technologies that use a proportional valve to prevent blow-off when there is a maximum negative pressure difference, as can be seen from the above detection process, the true density detection device of this application, through pulsed air intake (i.e., multi-stage air intake), can cooperate with the buffer chamber. Whether there is a high pressure difference between the intake chamber and the sample chamber 21, or a high pressure difference between the expansion chamber 22 and the sample chamber 21, high-pressure gas can first enter the buffer chamber, and then the sample valve 28 is opened to quickly achieve pressure balance between the buffer chamber and the sample chamber 21. This eliminates the need for a proportional valve, reducing device cost and space occupation. Specifically, under forward air intake and high pressure differential conditions, after each intake of air through the air inlet, the gas will first be stored in the buffer chamber, and then the sample valve 28 will be opened to allow the gas in the buffer chamber to enter the sample chamber 21. Similarly, under reverse air intake and high pressure differential conditions, after each exhaust of the expansion chamber 22, the gas will first be stored in the buffer chamber, and then the sample valve 28 will be opened to allow the gas in the buffer chamber to enter the sample chamber 21.

[0049] Furthermore, existing true density meters require adjustments to the air intake and exhaust directions in different modes, which makes the internal piping of the instrument very complex. However, as can be seen from the above detection process, the true density detection device of this application does not require adjustments to the air intake and exhaust directions, whether the air intake is in the forward or reverse direction. This simplifies the setup of the air path module 2, reduces the cost of the device, and reduces the number of leakage points while ensuring measurement accuracy and anti-flying function.

[0050] It should be explained that the specific configuration of the buffer chamber is not fixed and can be modified by those skilled in the art according to requirements. For example, although in this embodiment the buffer chamber is composed of the connecting spaces between the various channels, its configuration is not fixed. In an alternative embodiment, the buffer chamber can be configured as an independent compartment like the expansion chamber 22. However, considering the normal function of the buffer chamber, its volume should be minimized as much as possible. Therefore, forming the buffer chamber through the connecting spaces between the channels is a better choice. Furthermore, although in this embodiment the various channels are constructed through the body of the gas path module 2, its configuration is not mandatory. In an alternative embodiment, the various channels can be configured as external pipelines. That is, any of the connections between the air inlet, exhaust outlet, sample chamber 21, and expansion chamber 22 can be achieved through external pipelines. In this case, the configuration of the buffer channel 25 is not mandatory. For example, the buffer chamber can be constructed using a three-way valve, where the three ports of the three-way valve can be connected to the air inlet channel 23, the exhaust channel 24, and the sample chamber 21, respectively. However, considering the need to reduce leakage points, constructing each channel through the main body of the air circuit module 2 is a better option.

[0051] Furthermore, the configuration of the expansion chamber 22 is not fixed; those skilled in the art can modify its specific configuration as needed. For example, although two expansion chambers 22 are provided in this embodiment, their configuration is not fixed. In an alternative embodiment, the number of expansion chambers can be one, three, etc. As another example, in this embodiment, the volume of the smallest expansion chamber 22 is 10ml, and the volume of the buffer chamber is 2ml. However, those skilled in the art can also change the volume of the buffer chamber as needed. In an alternative embodiment, the volume of the buffer chamber can be set to 1ml, in which case the ratio of the buffer chamber volume to the smallest expansion chamber 22 volume is 1:10, which can also quickly balance the pressure difference while taking into account the intake speed. Of course, those skilled in the art can also modify the diameter of the intake channel 23, exhaust channel 24, and buffer channel 25 as needed, as long as it does not impede the normal functioning of the buffer chamber.

[0052] It should also be explained that the true density detection device's sample escape prevention function includes two aspects. One is flow restriction, that is, the aforementioned buffer chamber at the source is used to prevent the sample from escaping due to high pressure difference during the air intake process. The other is filtration, which is achieved by setting up the sample cup assembly 9 to prevent the sample from leaving the sample cup assembly 9, thus preventing inaccurate detection results and avoiding damage to the device.

[0053] In existing technologies, the cover 92 in the sample cup assembly 9 is typically constructed from a single piece of sintered filter element or filter sheet. Its side surface machining is poor, making it impossible to install the sealing ring 924. This results in a gap between the cover 92 and the cup body 91 that is much larger than the filtration diameter of the cover 92 and the diameter of the powder sample. During testing, this causes extremely fine sample powder to escape from the gap between the cover 92 and the cup body 91 when there are changes in air pressure or airflow. Furthermore, each sample loading process requires opening and closing the cover 92, and these operations wear down the cover 92. Therefore, frequent measurements of the true density meter's actual volume are necessary to maintain the accuracy of the true density meter.

[0054] In this embodiment, the main body 922 of the cover 92 and the cup body 91 can be sealed by a sealing ring 924, and the filter element 923 on the cover 92 can cover the vent hole 921, thereby achieving filtration. When the sample cup assembly 9 enters the sample chamber 21 and docks and seals with the measurement interface of the sample chamber 21, the top of the filter element 923 can rest against the bottom of the measurement interface. At this time, suction and air intake are performed through the vent hole 921, and the filter element 923 will not be blown away. Furthermore, since the filter element 923 is set as a small circular piece, its diameter is smaller than that of the filter element 923 in the prior art, resulting in a smaller side area, which significantly reduces the gaps that may cause leakage. At the same time, the bottom surface of the filter element 923 is in contact with the plane of the main body 922, which improves the side seal to a front seal, further reducing the possibility of leakage. In addition, there is no need to operate the filter element 923 each time the sample is changed, so the wear of the filter element 923 is avoided, and the frequency of re-measuring the true volume of the filter element 923 is significantly reduced.

[0055] Those skilled in the art will understand that the specific configuration of the sample cup assembly 9 is not fixed. In one alternative embodiment, the cover 92 may be constructed using only the filter element 923, omitting the metal cover 92 and the sealing ring 924. However, considering both sealing and filtration effects, assembling the cover 92 using the main body 922, filter element 923, and sealing ring 924 is a preferred choice. In another alternative embodiment, the filter element 923 may be a sieve plate, sintered filter, filter element, or filter plate made of different materials, such as a PTFE powder sintered filter, a stainless steel powder sintered filter, a titanium powder sintered filter, a PTFE / PP filter element, etc. The main body 922 of the cup body 91 and the cover 92 may also be made of copper, stainless steel, or titanium.

[0056] Furthermore, even when the cover 92 includes a main body 922, a filter element 923, and a sealing ring 924, the specific arrangement of the cover 92 is not fixed. In one alternative embodiment, the second groove 9222 around the main body 922 can be omitted, in which case the sealing ring 924 is directly fitted onto the periphery of the main body 922. In another alternative embodiment, those skilled in the art can modify the shape and position of the vent 921, the first groove 9221, and the filter element 923 as needed.

[0057] Those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments in the claims of this application can be used in any combination.

[0058] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A true density detection device, characterized in that, The true density detection device includes a gas path module (2), which includes a buffer chamber, a sample chamber (21), and an expansion chamber (22). The buffer chamber is connected to both the air inlet and the air outlet of the gas path module (2). The volume of the buffer chamber is smaller than the volumes of the sample chamber (21) and the expansion chamber (22). The sample chamber (21) and the expansion chamber (22) are both connected to the buffer chamber, and the sample chamber (21) and the expansion chamber (22) can only be connected through the buffer chamber. The gas path module (2) includes an air inlet channel (23), an air outlet channel (24), and a buffer channel (25). One end of the air inlet channel (23) is provided with the air inlet, and one end of the air outlet channel (24) is provided with the air outlet. The buffer channel (25) is connected to the air inlet channel (23) and the air outlet channel (24) respectively. The sample chamber (21) is connected to the air inlet channel (23) through a sample valve (28). The exhaust channel (24) or the buffer channel (25) is connected. The expansion chamber (22) is connected to the intake channel (23), the exhaust channel (24) or the buffer channel (25) through the expansion valve (29). The space between the intake channel (23), the exhaust channel (24), the buffer channel (25), the sample valve (28) and the expansion valve (29) forms the buffer chamber. The intake method is pulse intake. When the intake is in the forward direction and there is a high pressure difference, after each intake from the intake port, the gas will be stored in the buffer chamber first, and then the sample valve (28) will be opened to allow the gas in the buffer chamber to enter the sample chamber (21). When the intake is in the reverse direction and there is a high pressure difference, each time the expansion chamber (22) exhausts, the gas will also be stored in the buffer chamber first, and then the sample valve (28) will be opened to allow the gas in the buffer chamber to enter the sample chamber (21).

2. The true density detection device according to claim 1, characterized in that, The volume of the buffer chamber is set to be less than or equal to 2 ml.

3. The true density detection device according to claim 1, characterized in that, The diameters of the intake channel (23), the exhaust channel (24), and the buffer channel (25) are all set to be less than 2 mm.

4. The true density detection device according to claim 1, characterized in that, The expansion compartment (22) is configured as a plurality of such compartments, and the plurality of such expansion compartments (22) have different volumes.

5. The true density testing device according to any one of claims 1-4, characterized in that, The ratio of the volume of the buffer compartment to the volume of the smallest expansion compartment (22) is 1:5 to 1:

10.

6. The true density detection device according to claim 1, characterized in that, The true density detection device includes a sample cup assembly (9), which includes a cup body (91) and a lid (92). The cup body (91) is used to hold the sample, and the lid (92) is placed on the cup body (91). The lid (92) is provided with a vent hole (921). The lid (92) is used to connect with the measurement interface of the sample chamber (21), and the lid (92) can filter the sample in the airflow.

7. The true density detection device according to claim 6, characterized in that, The cover (92) includes a main body (922), a filter element (923), and a sealing ring (924). A first groove (9221) is provided in the middle of the upper surface of the main body (922), and a vent hole (921) is provided at the bottom of the first groove (9221). The filter element (923) is disposed in the first groove (9221) and covers the vent hole (921). The sealing ring (924) is used to achieve a seal between the main body (922) and the cup body (91).

8. The true density detection device according to claim 7, characterized in that, The main body (922) has a second groove (9222) on its periphery, and the sealing ring (924) is set as an O-ring, and the sealing ring (924) is set in the second groove (9222).

9. The true density detection device according to claim 7, characterized in that, The filter element (923) is configured as any one of a sieve plate, a sintered filter, a filter element, and a filter plate; and / or the cup body (91) and / or the main body (922) are made of any one of aluminum, copper, stainless steel, and titanium.

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