Microflow measurement device and measurement method based on the mass method

Abstract

The present invention discloses a minute flow rate measuring device and measuring method based on the mass method, the measuring device comprising: an internal evaporation prevention cover; an external evaporation prevention assembly; a weighing balance; a liquid collection container; a packing assembly provided inside the liquid collection container, made of a low water absorption material, breathable, and having a containment cavity for containing the liquid to be measured between its lower end and the bottom of the liquid collection container; a capillary receiving tube having a liquid receiving port and a liquid discharge port at its upper and lower ends, respectively, with its lower end extending vertically through the packing assembly into the containment cavity and its upper end curving horizontally through the internal evaporation prevention cover; and a discharge tube installed horizontally, with its outlet passing through the external evaporation prevention assembly and aligned horizontally with the liquid receiving port, and maintaining a first interval, thereby drawing the liquid discharged from the outlet into the liquid receiving port at intervals.

Description

Technical Field

[0001] The present invention relates to the technical field of flow measurement, and specifically to a micro flow measurement device and a measurement method based on the mass method.

Background Art

[0002] Conventional micro flow measurement technologies basically adopt the mass method. The liquid to be measured for flow is injected into a container, and the cumulative flow is weighed at regular intervals to obtain the average flow error. According to the liquid collection form, it can be classified into those where the liquid outlet needle is immersed in the liquid surface in the collection container or suspended. The liquid collection form where it is immersed below the liquid surface can be further classified according to whether it is covered with an oil film or not.

[0003] In actual applications, these collection forms have their respective advantages and disadvantages. When the needle is immersed in the liquid surface, the accumulation of liquid on the needle is eliminated, but the surface tension formed between the needle and the liquid surface in the container generates an additional force that acts on the balance, causing the liquid level to continuously rise while continuously injecting the liquid into the container. In the process, the liquid outlet pressure of the needle and the surface tension continuously change, causing measurement errors. Furthermore, when the liquid surface is covered with an oil film, this error becomes even larger.

[0004] As another improvement method, the needle is vertically suspended in the capillary pipeline of the collection container to form a continuous liquid column with an extremely small height. At the same time, the liquid is guided to continuously flow downward to maintain the liquid level height unchanged, thereby avoiding the influence of the change in liquid level height on the surface tension. However, the liquid column still applies a force between the needle and the container. When the flow rate changes slightly, the change in the form of the liquid column causes a change in the acting force of the accessory, further causing errors. Neither of the above two main micro liquid flow measurement methods can enable the weighing balance to obtain a stable indication due to continuous liquid injection and surface tension. Therefore, only the instantaneous value can be dynamically read, resulting in a large measurement error.

[0005] When a needle is placed on the liquid surface and droplets are allowed to form and naturally drip into the container, sufficient time is given for the balance to read the reading between each droplet. However, problems such as nonlinear evaporation during droplet formation, dropping shock, and discrepancies in the amount of liquid remaining at the start and end times of the needle formation can lead to larger measurement errors.

[0006] Furthermore, in the case of open-type collection containers, if the liquid surface is not covered with an oil film, a large amount of evaporation will occur, affecting the measurement results. [Overview of the project] [Problems that the invention aims to solve]

[0007] The main objective of this invention is to provide a micro-flow measurement device and measurement method based on the mass method in order to solve the problem that there are still large measurement errors in micro-flow measurement in related technologies. [Means for solving the problem]

[0008] To achieve the above objective, the present invention, An internal evaporation prevention cover, An outer evaporation prevention assembly is provided covering the aforementioned inner evaporation prevention cover, A weighing balance provided inside the aforementioned internal evaporation prevention cover, A liquid collection container is provided inside the aforementioned internal evaporation prevention cover and placed on the aforementioned weighing balance, A packing assembly provided within the liquid collection container, manufactured from a low water absorption material, breathable, and having a containment cavity between its lower end and the bottom of the liquid collection container for containing the liquid to be measured, It is installed in an L-shape, with a liquid receiving port and a liquid discharge port at both the upper and lower ends, the lower end of which penetrates the packing material assembly vertically and extends into the containment cavity, and the upper end of which penetrates the internal evaporation prevention cover and curves horizontally, A minute flow rate measuring device based on the mass method is provided, comprising a discharge tube that includes a horizontal discharge segment, the end of which has a discharge port, the discharge port passing through the external evaporation prevention assembly and aligned horizontally with the liquid receiving port, and maintaining a first interval, thereby drawing the liquid discharged from the discharge port into the liquid receiving port at intervals, and the liquid outlet causing the liquid to drip into a liquid collection container at intervals.

[0009] Furthermore, the first interval is smaller than the outer diameter of the outlet and larger than the maximum distance required to form a continuous liquid column between the outlet and the liquid receiving port.

[0010] Furthermore, the first interval is smaller than half the outer diameter of the liquid outlet.

[0011] Furthermore, a conical structure is installed at the end of the horizontal outlet segment of the outlet pipe closest to the capillary receiving tube, and the outer diameter of the end of the conical structure closest to the capillary receiving tube is equal to the inner diameter of the liquid receiving opening. The first interval is the distance between the end of the conical structure closest to the capillary receiving tube and the end of the liquid receiving port.

[0012] Furthermore, the capillary tube includes a first tube segment and a second tube segment communicating with each other, the inner diameter of the second tube segment being larger than the inner diameter of the first tube segment, the second tube segment extending vertically through the packing assembly into the containment cavity, and the liquid outlet located at the lower end of the second tube segment. The first pipe segment includes one horizontal segment, and the liquid receptacle is located at the end of the horizontal segment.

[0013] Furthermore, the first pipe segment further includes one corner segment, the inner surface of which is set as an arc-shaped surface, and the corner radius of which is 1D to 2D, where D is the outer diameter of the first pipe segment.

[0014] Furthermore, the first pipe segment is installed in a cylindrical shape.

[0015] Furthermore, the first pipe segment and the second pipe segment are connected via a transition segment, the transition segment is installed in a conical shape, the smaller diameter end of the transition segment is connected to the first pipe segment, and the larger diameter end of the transition segment is connected to the second pipe segment.

[0016] Furthermore, the angle between the generatrix and axis of the transition segment is 10° to 15°.

[0017] The filler assembly can be selected from one or more of the following microporous polymer materials: polyamide, polyethylene, and polypropylene.

[0018] Optionally, the packing assembly includes a seal packing and an exhaust pipe, the seal packing being made of a low water absorption material, and the exhaust pipe passing through the seal packing and used for ventilation.

[0019] Furthermore, the inner diameter of the exhaust pipe is smaller than the inner diameter of the outlet pipe.

[0020] Furthermore, the distance between the liquid outlet and the inner bottom surface of the liquid collection container is greater than the height of the liquid in the containment cavity during measurement.

[0021] Furthermore, the seal filler is elastic, and the seal filler is inserted and fixed inside the liquid collection container. The seal filling material is provided with through holes and mounting holes, the capillary receiving tube is fitted tightly through the through holes, and the exhaust pipe is fitted tightly through the mounting holes.

[0022] Furthermore, multiple mounting holes are provided, with the exhaust pipe installed in at least one of the mounting holes, and removable seal plugs installed in the other mounting holes.

[0023] Furthermore, the seal plug is manufactured from a low water absorption material, and the lower end surface of the seal plug is flush with the lower end surface of the seal filler.

[0024] Furthermore, the external evaporation prevention assembly includes an external windproof cover and an external evaporation prevention cover. The external evaporation prevention cover is provided above the internal evaporation prevention cover, and the external windproof cover is provided to cover the outside of the external evaporation prevention cover and the internal evaporation prevention cover. The upper end of the capillary receiving tube extends into the external evaporation prevention cover, and the liquid outlet of the liquid outlet pipe passes through the external windproof cover and the external evaporation prevention cover in sequence and is horizontally aligned with the liquid receiving port. Inside the external evaporation prevention cover, a first humidity adjustment structure for increasing the humidity inside the external evaporation prevention cover is provided.

[0025] Furthermore, the micro flow measurement device further includes an evaporation well. The evaporation well is provided inside the internal evaporation prevention cover. An axially penetrating mounting chamber is provided inside the evaporation well. The mounting chamber is fitted outside the liquid collection container and the weighing scale, and there is a gap between the liquid collection container and the weighing scale. In the evaporation well, a second humidity adjustment structure for increasing the humidity inside the mounting chamber is installed.

[0026] According to another aspect of the present invention, the above micro flow measurement device is adopted. A step of extruding the liquid to be measured for flow from the liquid outlet of the liquid outlet pipe to form a slightly convex liquid surface. A step of sucking the liquid extruded from the liquid outlet at a T1 time interval using the liquid receiving port of the capillary receiving tube. After the liquid first drips from the liquid discharge port of the capillary receiving tube into the liquid collection container, a step of reading the indication of the weighing scale at each T1 time interval. A step of determining the liquid flow rate based on the indication of the weighing scale at each T1 time is provided, including a micro flow measurement method.

Effect of the Invention

[0027] In an embodiment of the present invention, first, by aligning the outlet tube and the capillary receiving tube horizontally, a continuous liquid flow rate is converted into equally timed suction, thereby providing a stable reading time for the weighing balance and improving the reproducibility and accuracy of flow rate measurement. Next, the arrangement of the internal evaporation prevention cover and the external windbreak assembly makes it difficult for the liquid between the outlet pipe and the capillary receiving pipe, and the liquid flowing into the liquid collection container via the capillary receiving pipe, to evaporate due to the influence of external airflow. The liquid drawn in by the capillary tube is stored within the tube, and because the inner diameter of the capillary tube is extremely small, the contact area between its port and the outside air is also extremely small, thereby significantly reducing the amount of liquid evaporation. Furthermore, because the liquid receiving port of the capillary tube and the outlet port of the outlet tube are aligned horizontally, the direction of movement of the extruded liquid is perpendicular to the direction of gravity, reducing the protrusion height of the micro-convex liquid surface. This allows the capillary tube to be brought as close as possible to the outlet port, reducing the volume and mass of the micro-convex liquid surface and minimizing the influence of evaporation and residual droplets on the measurement results. Simultaneously, even if a momentary minute liquid column is generated between the outlet port and the liquid receiving port, the capillary force between the liquid receiving end of the capillary tube, the minute liquid column, and the outlet port is horizontal and perpendicular to the measurement direction of the weighing balance, thus reducing the influence on the balance's reading. Finally, a packing assembly is placed inside the liquid collection container. Since the packing assembly has low water absorption and permeability, after the liquid is injected into the containment chamber within the liquid collection container, the air inside the containment chamber can be expelled through the packing assembly, matching the pressure inside the containment chamber with the ambient pressure and ensuring a constant liquid suction rate regardless of the amount of liquid injected.

[0028] As described above, the present invention achieves technical effects that reduce minute flow rate measurement errors and improve minute flow rate measurement accuracy by improving the measuring device in multiple directions, thereby solving the problem of large measurement errors still existing in related technologies for measuring minute flow rates.

[0029] The drawings, which constitute part of the present invention, are provided to further understand the invention and to clarify other features, purposes, and advantages of the invention. The drawings and descriptions of exemplary embodiments of the invention are for interpretation purposes only and do not constitute an unreasonable limitation of the invention. [Brief explanation of the drawing]

[0030] [Figure 1] This is a schematic cross-sectional diagram of a microflow rate measuring device according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of the transparent structure of a microflow measuring device according to an embodiment of the present invention. [Figure 3] This is a schematic diagram of the structure of a liquid outlet tube and a capillary receiving tube according to an embodiment of the present invention. [Figure 4] This is a schematic diagram of the structure of a capillary tube relating to one embodiment of the present invention. [Figure 5] This is a schematic cross-sectional diagram of a microflow rate measuring device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0031] To enable those skilled in the art to better understand the means of the present invention, the technical solutions of the embodiments of the present invention will be described clearly and completely below with reference to the drawings of the embodiments of the present invention, and obviously, the embodiments described are merely some embodiments of the present invention, not all embodiments. Any other embodiments that those skilled in the art can obtain without creative work based on the embodiments of the present invention should fall within the scope of protection of the present invention.

[0032] Furthermore, terms such as "First," "Second," etc., in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not intended to describe a specific order or sequence. It should be understood that the data used in this manner are interchangeable where appropriate for the convenience of the embodiments of the invention described herein.

[0033] In this invention, directions or positional relationships indicated by terms such as "up," "down," and "inside" are directions or positional relationships based on the illustrations. These terms are used primarily to better describe the invention and its embodiments, and do not necessarily limit the devices, elements, or components to having a specific direction or being configured or operated in a specific direction.

[0034] Furthermore, some of the above terms can be used to indicate meanings other than direction or positional relationships; for example, the term "above" can, in some cases, indicate a dependency or connection. Those skilled in the art will understand the specific meanings of these terms in the present invention depending on the specific circumstances.

[0035] Furthermore, terms such as "installed," "provided," "connected," and "fixed" should be understood in a broad sense. For example, "connection" may be a fixed connection, a detachable connection, or an integrated structure; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection via an intermediate medium; and it may be internal communication between two devices, elements, or components. Those skilled in the art will be able to understand the specific meaning of the above terms in the present invention depending on the specific situation.

[0036] Furthermore, the term "plural" means two or more.

[0037] Furthermore, the embodiments and features of the present invention can be combined with each other, as long as they do not contradict each other. The present invention will now be described in detail with reference to the drawings and embodiments.

[0038] To solve the problems of related technologies, as shown in Figures 1 to 3, embodiments of the present invention provide a minute flow rate measuring device based on the mass method, and this measuring device is Internal evaporation prevention cover 4, An outer evaporation prevention assembly 15 is provided covering the inner evaporation prevention cover 4, A weighing balance 3 is provided inside the internal evaporation prevention cover 4, A liquid collection container 1 is provided in the internal evaporation prevention cover 4 and placed on the weighing balance 3, A packing assembly 5 is provided inside the liquid collection container 1, is made of a low water absorption material, is breathable, and has a containment cavity 101 for containing the liquid to be measured between its lower end and the bottom of the liquid collection container 1. It is installed in an L-shape, with a liquid receiving port 83 and a liquid discharge port 82 at both the upper and lower ends, the lower end of which penetrates the packing material assembly vertically and extends into the containment cavity 101, and the upper end of which penetrates the internal evaporation prevention cover 4 and curves horizontally as a capillary receiving tube 8, The apparatus includes a horizontal discharge segment, the end of which is provided with a discharge port 70, the discharge port 70 passing through the external evaporation prevention assembly 15 and aligned horizontally with the liquid receiving port 83, and maintaining a first gap, the discharged liquid from the discharge port 70 is drawn into the liquid receiving port 83 at intervals, and the liquid outlet 82 drops the liquid into the liquid collection container 1 at intervals, and the discharge pipe 7 includes a horizontal discharge segment, the end of which is provided with a discharge port 70, the discharge port 70 passes through the external evaporation prevention assembly 15 and is aligned horizontally with the liquid receiving port 83, and maintains a first gap, thereby drawing the liquid discharged from the discharge port 70 into the liquid receiving port 83, and the liquid outlet 82 drops the liquid into the liquid collection container 1 at intervals.

[0039] In this embodiment, the installation process for the micro-flow measuring device involves placing the liquid collection container 1 on a weighing balance 3 and then placing the packing assembly 5 inside the liquid collection container 1. Of course, it is also possible to first place the packing assembly 5 inside the liquid collection container 1 and then place the liquid collection container 1 with the packing assembly 5 attached onto the weighing balance 3. Depending on the type of packing material, the arrangement method of the packing assembly 5 will differ, and if the packing assembly 5 includes a foamed type of packing material, the packing assembly 5 can be molded inside the liquid collection container 1 by a foaming method. If the packing assembly 5 is a single independent component, the packing assembly 5 can be installed and used inside the liquid collection container 1. In order to improve the liquid weighing capacity of the liquid collection container 1, the weight of the packing assembly 5 should be kept as small as possible; that is, the packing assembly 5 should be manufactured from lightweight material. In this embodiment, there is a containment cavity 101 for accommodating the liquid to be measured between the lower end of the packing assembly 5 and the bottom of the liquid collection container 1. This containment cavity 101 can accommodate a predetermined amount of liquid, i.e., the medium to be measured 2, and the volume of the containment cavity 101 must be larger than the volume of liquid required to complete the entire measurement process.

[0040] Furthermore, after the packing assembly 5 is placed inside the liquid collection container 1, the containment cavity 101 forms a relatively sealed space, thereby reducing the influence of external airflow on the rate of evaporation of the liquid inside the containment cavity 101, and also limiting the containment cavity 101 to one suitable range, which is advantageous for performing measurements.

[0041] In order to smoothly inject the liquid in the liquid receiving tube into the containment cavity 101, it is necessary to expel the air inside the containment cavity 101 at the same time as injecting the liquid into the containment cavity 101, thereby maintaining the pressure balance between the inside and outside and ensuring smooth liquid flow.

[0042] The present invention, by installing the packing assembly 5, creates a relatively sealed environment within the containment cavity 101 of the liquid collection container 1, making the liquid to be measured that enters the containment cavity 101 less susceptible to external airflow and reducing the evaporation rate of the liquid to be measured. Furthermore, the packing assembly 5 restricts the containment cavity 101 to one appropriate range, and because the packing assembly 5 is permeable, when the liquid to be measured flows into the containment cavity 101, gases inside the containment cavity 101 can be discharged, allowing the liquid to be measured to flow in smoothly.

[0043] In this embodiment, since an internal evaporation prevention cover 4 and an external evaporation prevention assembly 15 are provided, exhaust holes may be provided in the internal evaporation prevention cover 4 and the external evaporation prevention assembly 15 to allow air to flow in the internal space, or the lower ends of the internal evaporation prevention cover 4 and the external evaporation prevention assembly 15 may be in non-seal contact with the mounting surface (for example, the top surface of a desk).

[0044] After placing the liquid collection container 1, an internal evaporation prevention cover 4 can be installed to cover the weighing balance 3 and the liquid collection container 1. By installing the internal evaporation prevention cover 4, the liquid in the liquid collection container 1 becomes less susceptible to changes in external airflow, thereby reducing the amount of evaporation of the liquid in the liquid collection container 1 and further reducing measurement errors. The overall size of the internal evaporation prevention cover 4 can be designed according to the size of the weighing balance 3 and the liquid collection container 1, and this embodiment is not limited thereto. A first mounting hole may be provided at the upper end of the internal evaporation prevention cover 4, which corresponds to the upper and lower parts of the middle of the liquid collection container 1 and is used for the passage of the capillary receiving tube 8.

[0045] Furthermore, when the filler assembly 5 is formed inside the liquid collection container 1 by foaming, the capillary tube 8 is positioned in the middle of the liquid collection container 1 using specific tooling, and then the filler assembly 5 is formed between the capillary tube 8 and the side wall of the liquid collection container 1.

[0046] In this embodiment, the capillary tube 8 is installed in an L-shape, that is, it includes one horizontal tube segment 84 and one vertical tube segment 85, with the liquid receiving port 83 and liquid outlet 82 of the capillary tube 8 located at the ends of the horizontal tube segment 84 and the vertical tube segment 85, respectively. The vertical tube segment 85 extends through the first mounting hole of the internal evaporation prevention cover 4 into the packing assembly 5 and can further penetrate the packing assembly 5, allowing the liquid in the capillary tube 8 to be injected into the containment cavity 101 of the liquid collection container 1. The horizontal tube segment 84 of the capillary tube 8 is located above the internal evaporation prevention cover 4 and is used in cooperation with the outlet pipe 7 to draw the liquid pushed out from the outlet pipe 7 into the capillary tube 8.

[0047] After positioning the capillary tube 8, the external evaporation prevention assembly 15 can be installed to cover the outside of the internal evaporation prevention cover 4 and the capillary tube 8. A second mounting hole may be provided on the side of the external evaporation prevention assembly 15, and at least a portion of the outlet pipe 7 may pass through the second mounting hole horizontally to correspond to the liquid receiving port 83 of the capillary tube 8. During the liquid injection process, the liquid flows out from the outlet 70 of the outlet pipe 7 and is drawn into the capillary tube 8 via the liquid receiving port 83. Under the action of the external evaporation prevention assembly 15, the influence of changes in the external airflow on the liquid between the outlet 70 and the liquid receiving port 83 is reduced, the amount of liquid evaporation in that portion is reduced, and thus measurement errors can be reduced.

[0048] Similarly, the outlet pipe 7 has a portion that is aligned horizontally with the horizontal portion of the capillary receiving pipe 8, and the outlet 70 of the outlet pipe 7 is located at the end of this portion of the outlet pipe 7. In this embodiment, the outlet 70 of the outlet pipe 7 does not directly contact the liquid receiving port 83 of the capillary receiving pipe 8, and the two maintain a predetermined distance apart, i.e., a first distance apart. The specific value of the first distance apart should satisfy the following conditions: the liquid pushed out from the outlet 70 can form a micro-convex liquid surface of a predetermined size before contacting the liquid receiving port 83, be drawn into the capillary receiving pipe 8 via the liquid receiving port 83, and after drawing in, a continuous liquid column should not be formed between the outlet 70 and the liquid receiving port 83. In other words, the capillary receiving pipe 8 can draw in the liquid pushed out from the outlet 70 at intervals and drop the liquid into the liquid collection container 1 at intervals through the liquid discharge port 82.

[0049] In this embodiment, the flow rate measurement method using the micro-flow rate measuring device involves pushing the liquid to be measured as the measurement medium 2 out from the outlet 70 of the outlet pipe 7 to form a micro-convex liquid surface. After the liquid surface comes into contact with the liquid receiving port 83 of the capillary receiving tube 8, it is rapidly drawn in and cut by capillary action and gradually accumulated in the vertical part of the capillary receiving tube 8. After a predetermined mass of liquid has accumulated in the vertical part, the liquid drips from the liquid outlet 82 at the lower end of the vertical part into the liquid collection container 1. Next, the current mass of the liquid collection container 1 can be obtained using the weighing balance 3, and the mass of the dripped liquid can be obtained, thereby allowing the liquid flow rate to be obtained using the mass method.

[0050] In this embodiment, first, by aligning the outlet tube 7 and the capillary receiving tube 8 horizontally, the continuous liquid flow rate is converted into equally timed suction, thereby providing a stable reading time for the weighing balance 3, improving the reproducibility and accuracy of flow rate measurement. Next, the arrangement of the inner evaporation prevention cover 4 and the outer evaporation prevention assembly 15 makes it difficult for the liquid between the outlet pipe 7 and the capillary receiving pipe 8, and the liquid flowing into the liquid collection container 1 via the capillary receiving pipe 8, to evaporate due to the influence of the external airflow. The liquid drawn in by the capillary tube 8 is stored inside the capillary tube 8, and because the inner diameter of the capillary tube 8 is extremely small, the contact area between its port and the outside air is also extremely small, thereby significantly reducing the amount of liquid evaporation. Furthermore, since the liquid receiving port 83 of the capillary receiving tube 8 and the outlet port 70 of the outlet tube 7 are aligned horizontally, the direction of movement of the extruded liquid is perpendicular to the direction of gravity, which reduces the protrusion height of the micro-convex liquid surface. This allows the capillary receiving tube 8 to be brought as close as possible to the outlet port 70, reducing the volume and mass of the micro-convex liquid surface and minimizing the influence of evaporation and residual droplets on the measurement results. Simultaneously, even if a momentary minute liquid column is generated between the outlet port 70 and the liquid receiving port 83, the capillary force between the liquid receiving end of the capillary receiving tube 8, the minute liquid column, and the outlet port 70 is horizontal and perpendicular to the measurement direction of the weighing balance 3, thus reducing the influence on the reading of the weighing balance 3. At the same time, because the liquid outlets 82 of the capillary receiving tube 8 drop the liquid into the liquid collection container 1 at intervals, a continuous liquid column is not formed between the liquid outlets 82 and the liquid collection container 1. As a result, there is no additional force acting between the capillary receiving tube 8 and the liquid collection container 1, and measurement errors are not caused even if the flow rate changes.

[0051] Finally, a packing material assembly 5 is placed inside the liquid collection container 1. Since the packing material assembly 5 has low water absorption and permeability, after the liquid is injected into the containment chamber inside the liquid collection container 1, the air inside the containment chamber can be expelled through the packing material assembly 5, matching the pressure inside the containment chamber with the ambient pressure and ensuring a constant liquid suction rate without being affected by the amount of liquid injected.

[0052] As described above, the present invention achieves technical effects that reduce minute flow rate measurement errors and improve minute flow rate measurement accuracy by improving the measuring device in multiple directions, thereby solving the problem of large measurement errors still existing in related technologies for measuring minute flow rates.

[0053] Furthermore, in order to facilitate the formation of a predetermined micro-convex liquid at the end of the outlet pipe 7, in this embodiment, the end of the horizontal outlet segment of the outlet pipe 7 closest to the capillary receiving pipe 8 is set up as a conical structure, the outer diameter of the conical structure at the end closest to the capillary receiving pipe 8 is equal to the diameter of the liquid receiving port 83, and the first interval is the interval between the conical structure at the end closest to the capillary receiving pipe 8 and the end of the liquid receiving port 83.

[0054] The first interval should satisfy a predetermined condition in order for the capillary tube 8 to be able to draw in the liquid to be measured at intervals. If the first interval is too small, a continuous liquid column will be formed between the outlet 70 of the outlet tube 7 and the liquid receiving port 83 of the capillary tube 8. At this time, since the capillary tube 8 is in the process of continuous drawing, the liquid outlet 82 of the capillary tube 8 will be in a continuous dripping state, and there will not be an appropriate time to read the reading on the weighing balance 3. If the first interval is too large, the slightly convex liquid surface pushed out from the outlet 70 will not be able to contact the liquid receiving port 83 of the capillary tube 8, and it may not be possible to draw the liquid into the capillary tube 8 properly.

[0055] Therefore, in this embodiment, as shown in Figure 3, the first interval is smaller than the outer diameter of the outlet 70 and larger than the maximum distance required to form a continuous liquid column between the outlet 70 and the liquid receiving port 83. Furthermore, in one preferred embodiment, the first interval is smaller than half the outer diameter of the outlet 70. In one embodiment, the mass of the smallest micro-convex droplet pushed out from the outlet 70 is 0.03 mg, and the degree of droplet protrusion can be determined according to the tension of the liquid.

[0056] In this embodiment, the capillary receiving tube 8 is installed in an L-shape, and further improvements are made. Specifically, because the inner diameter of the capillary receiving tube 8 is very small, the liquid capacity that can be stored is extremely limited, and if the cumulative volume of the aspirated liquid is greater than the volume of the capillary tube, it will drip into the collection container. Once it drips, the liquid spreads into a flat, thin layer, the surface area increases significantly, and the rate of evaporation increases rapidly. Therefore, in order to increase the liquid storage capacity of the capillary receiving tube 8 without affecting the capillary action of the capillary receiving tube 8 and to reduce the rate of liquid evaporation, the capillary receiving tube 8 in this embodiment has a variable diameter structure.

[0057] Specifically, as shown in Figures 1 and 2, in this embodiment, the capillary receiving tube 8 includes a first tube segment 80 and a second tube segment 81 that communicate with each other, the first tube segment 80 includes a horizontal tube segment 84, and the vertical tube segment 85 includes the second tube segment 81, the inner diameter of the second tube segment 81 is larger than the inner diameter of the first tube segment 80, the second tube segment 81 extends vertically through the packing assembly 5 into the containment cavity 101, the liquid outlet 82 is located at the lower end of the second tube segment 81, the first tube segment 80 includes one horizontal segment, and the liquid receiving port 83 is located at the end of the horizontal segment.

[0058] In this embodiment, the inner diameter of the first tube segment 80 is small, allowing it to draw in liquid under capillary action and hold a predetermined mass of liquid. The inner diameter of the second tube segment 81 is large, significantly increasing the liquid holding capacity, reducing the frequency of liquid dripping, and decreasing the amount of liquid evaporation. By combining the first tube segment 80 and the second tube segment 81, the capillary receiving tube 8 can draw in liquid smoothly, while simultaneously increasing the liquid holding capacity of the capillary receiving tube 8 and reducing the amount of liquid evaporation due to its small cross-sectional area.

[0059] Furthermore, in the present invention, since the capillary tube 8 is L-shaped, after being divided into a first tube segment 80 and a second tube segment 81, there are two types of structural configurations. In one configuration, the first tube segment 80 includes some horizontal tube segments 84, and the second tube segment 81 includes the remaining horizontal tube segments 84 and all vertical tube segments 85. In the other configuration, the first tube segment 80 includes all horizontal tube segments 84 and some vertical segments, and the second tube segment 81 includes the remaining vertical tube segments 85. The liquid needs to flow horizontally and then vertically within the capillary tube 8. Therefore, in order to facilitate the flow process of the liquid, the structural configuration of the capillary tube 8 in this embodiment is preferable in which the first tube segment 80 includes all horizontal tube segments 84 and some vertical tube segments 85, and the second tube segment 81 includes only the remaining vertical tube segments 85.

[0060] After the liquid is drawn in, it changes from horizontal to vertical flow within the capillary tube 8. The vertical liquid in the tube moves downward under the influence of gravity. However, since the direction of horizontal liquid movement is perpendicular to the direction of gravity, the horizontal liquid in the tube must be kept continuous with the vertical liquid at the corners of the capillary tube 8 in order to achieve continuous liquid drawing. For this reason, it is necessary to ensure that the corners of the capillary tube 8 are as smooth as possible to prevent localized resistance from occurring, which could cause interruptions in liquid continuity or gas buildup. If the radius of the corner is too large, the size of the capillary tube 8 extending outside the liquid collection container 1 will be too long, which may cause a balance load unevenness problem. Therefore, in this embodiment, the corner is further improved.

[0061] Specifically, in this embodiment, the first pipe segment 80 further includes a corner segment 801 for connecting the horizontal pipe segment 84 and the vertical pipe segment 85, the inner surface of the corner segment 801 is set as an arc-shaped surface, and the corner radius of the corner segment 801 is 1D to 2D, where D is the outer diameter of the first pipe segment 80. In addition, in order to ensure smooth suction of liquid, the liquid receiving port 83 facing the liquid outlet pipe 7 must be cylindrical, so that the capillary force does not change with changes in pipe diameter. Furthermore, both the first pipe segment 80 and the second pipe segment 81 are set in a cylindrical shape.

[0062] Since the inner diameter of the second pipe segment 81 is larger than the inner diameter of the first pipe segment 80, in order to reduce the effect of the change in the inner diameter of the pipe segment on the liquid in the first pipe segment 80 after it enters the second pipe segment 81, as shown in Figure 4, the first pipe segment 80 and the second pipe segment 81 in this embodiment are connected via a transition segment 84. The transition segment 84 is installed in a conical shape, with the smaller diameter end of the transition segment 84 connected to the first pipe segment 80 for a smooth transition, and the larger diameter end of the transition segment 84 connected to the second pipe segment 81 for a smooth transition. This allows the liquid to be sufficiently impregnated into the inner wall of the pipe after it enters the transition segment 84, and the air to be gradually discharged, thereby allowing the liquid to flow smoothly within the transition segment 84 and the second pipe segment 81. In one embodiment of the transition segment 84, the angle between the generatrix of the transition segment 84 and the axis of the transition segment 84 is 10° to 15°. The ratio of the inner diameter of the second pipe segment 81 to the inner diameter of the first pipe segment 80 is (1.5~3):1.

[0063] Furthermore, based on this, the connection between the small-diameter end of the transition segment 84 and the first pipe segment 80 may be chamfered in an arc shape, and the connection between the large-diameter end of the transition segment 84 and the second pipe segment 81 may also be chamfered in an arc shape.

[0064] In this invention, the filler assembly 5 needs to have low water absorption and permeability. Therefore, in one embodiment of the filler assembly 5, the filler assembly 5 is made of a porous material with low water absorption, and the micropores can be used to expel air after the liquid has been injected into the containment cavity 101 to balance the internal and external pressure. For example, polymer materials such as polyamide, polyethylene, and polypropylene having micropores can be used.

[0065] In another embodiment of the filler assembly 5, as shown in Figures 1 and 2, the filler assembly 5 includes a seal filler 50 and an exhaust pipe 51, the seal filler 50 being made of a low water absorption material, for example, a polymer material such as polyamide, polyethylene, or polypropylene can be used. In this embodiment, the seal filler 50 is not permeable, and the ventilation needs of the filler assembly 5 are met by the exhaust pipe 51, which penetrates the seal filler 50. After the liquid is injected into the containment cavity 101, the air inside the containment cavity 101 can be discharged through the exhaust pipe 51, thereby maintaining the internal and external pressure balance.

[0066] In this embodiment, the seal packing material 50 is made of a lightweight foamed material with low water absorption and high elasticity, and the inner diameter of the exhaust pipe 51 is the same as the inner diameter of the outlet pipe 7. The weight of the seal packing material 50 and the exhaust pipe 51 must be kept as small as possible to improve the liquid weighing capacity of the liquid collection container 1. After the seal packing material 50 is formed between the capillary receiving pipe 8 and the inner wall of the liquid collection container 1 using a foaming method, the inner diameter value of the outlet pipe 7 is obtained based on the minimum flow rate of the target to be measured, the same exhaust pipe 51 is selected as the standard exhaust pipe 51, and the exhaust pipe 51 is inserted into the seal packing material 50 to achieve constant velocity "liquid intake and gas discharge". Finally, for other target flow rates, a standard exhaust pipe 51 of an integer multiple is inserted into the seal packing material 50 to achieve pressure balance at different flow rates.

[0067] In another embodiment, the seal filler 50 may be a pre-formed member, and at least two through-holes may be formed in the seal filler 50 axially during pre-formation. One through-hole can be used as a through-hole for the second pipe segment 81 of the capillary receiving tube 8 to pass through and tightly fit, and the other through-hole can be used as a mounting hole for the exhaust pipe 51 to pass through and tightly fit. The outer diameter of the seal filler 50 matches the inner diameter of the liquid collection container 1, and the seal filler 50 can be inserted into and fixed in the liquid collection container 1 under the elastic action of the seal filler 50.

[0068] In one preferred embodiment of the exhaust pipe 51, since the exhaust pipe 51 is used to discharge gas from the liquid collection container 1 after the liquid has entered the liquid collection container 1, if the inner diameter of the exhaust pipe 51 is the same as the inner diameter of the outlet pipe 7, a pressure balance between the inside and outside of the liquid collection container 1 can be achieved. However, considering that the viscosity of the gas is lower than that of the liquid, the gas discharge rate is greater than the liquid intake rate, and the inner diameter of the exhaust pipe 51 also affects the amount of liquid evaporation in the liquid collection container 1. Therefore, in this embodiment, the inner diameter of the exhaust pipe 51 is set to be smaller than the inner diameter of the outlet pipe 7, thereby achieving constant velocity "liquid intake and gas discharge," further reducing the amount of liquid evaporation, and improving measurement accuracy.

[0069] In some environments, multiple exhaust pipes 51 may be required, so multiple mounting holes that penetrate axially may be pre-formed in the seal filler 50. If only one exhaust pipe 51 is needed, the exhaust pipe 51 may be inserted into only one mounting hole, and the remaining mounting holes may be sealed with seal plugs to prevent the liquid from evaporating from the mounting hole. If multiple exhaust pipes 51 are needed, the corresponding seal plugs may be selected and removed according to the number of exhaust pipes 51, the corresponding mounting holes may be opened, and the multiple exhaust pipes 51 may be inserted one by one into each mounting hole.

[0070] To facilitate the determination of the size of the cavity 101, the lower end surface of the seal plug is preferably flush with the lower end surface of the seal filler 50, thereby eliminating the need to consider the size of the space in the mounting hole where the exhaust pipe 51 is not inserted when determining the size of the cavity, and the seal plug is manufactured from a low water absorption material.

[0071] In order to easily discharge the gas in the containment cavity 101, in this embodiment, the lower end surface of the exhaust pipe 51 is flush with the lower end surface of the seal filler 50, or lower than the lower end surface of the seal filler 50.

[0072] In one embodiment of the exhaust pipe 51, the exhaust pipe 51 is installed in an L-shape, the vertical segment of the exhaust pipe 51 is provided in the mounting hole, and the horizontal segment of the exhaust pipe 51 is located above the sealant 50.

[0073] In the liquid collection container 1, the liquid outlet 82 of the capillary tube 8 must not come into contact with the surface of the collected liquid inside the liquid collection container 1. The advantages of this are as follows: First, by preventing the liquid outlet 82 from being inserted into the liquid surface, forces such as surface tension, buoyancy, and liquid pressure from affecting the flow of the liquid inside the capillary tube 8, thereby ensuring that the discharge flow rate is stable and does not change due to the rise in the liquid level inside the liquid collection container 1.

[0074] Next, in the conventional method where the liquid outlet 82 is inserted below the liquid surface, a predetermined amount of liquid must be pre-stored in the liquid collection container 1 to cover the liquid outlet 82. Thus, the effective weighing range is reduced, and as a result, a balance with a larger weighing capacity must be used, which in turn leads to a certain weighing error and limits the overall measurement accuracy. On the other hand, if the liquid outlet 82 of the capillary receiving tube 8 is controlled so that it does not come into contact with the collected liquid surface in the liquid collection container 1, it is no longer necessary to pre-store liquid in the liquid collection container 1. The effective weighing range occupies at least 70% or more of the balance, allowing the use of a balance with a smaller weighing capacity, further improving the minimum weighing capacity, and significantly improving the overall measurement accuracy.

[0075] To achieve the above objective, the length extending from the lower end of the seal packing material 50 of the liquid outlet 82 must be determined according to the volume of liquid to be collected in the liquid collection container 1. Specifically, the distance between the liquid outlet 82 and the inner bottom surface of the liquid collection container 1 is greater than the height of the liquid in the containment cavity 101 being measured.

[0076] To further reduce the evaporation rate of the liquid being measured, as shown in Figure 5, the micro-flow rate measuring device in this embodiment further includes an evaporation well 11, which is provided inside the internal evaporation prevention cover 4, and an axially penetrating mounting chamber 14 is provided inside the evaporation well 11, which is fitted to the outside of the liquid collection container 1 and the weighing balance 3, with a radial gap between the mounting chamber 14 and the liquid collection container 1 and the weighing balance 3, and a second humidity adjustment structure 13 for increasing the humidity inside the mounting chamber is installed in the evaporation well. In one embodiment of the second humidity adjustment structure 13, the second humidity adjustment structure 13 includes a housing groove opened at the upper end of the evaporation well, and an evaporable liquid is contained in the housing groove.

[0077] Specifically, in this embodiment, an evaporation well 11 is additionally positioned inside the internal evaporation prevention cover 4. The evaporation well 11 is fitted to the weighing balance 3 and the liquid collection container 1 via the mounting chamber 14. The evaporation well 11 maintains a gap between itself and the weighing balance 3 and the liquid collection container 1, and does not come into contact with them, so that the weight of the evaporation well 11 does not affect the weighing balance 3. In this embodiment, the mounting chamber 14 is a chamber that penetrates axially, the weighing balance 3 is located at the bottom of the mounting chamber 14, and the capillary receiving tube 8 can enter the liquid collection container 1 via the top of the mounting chamber 14.

[0078] To reduce the amount of liquid evaporation in the liquid collection container 1, it is necessary to improve the gas humidity inside the internal evaporation prevention cover 4. For this reason, in this embodiment, a containment groove 131 is provided at the upper end of the evaporation well 11, and the containment groove 131 is filled with evaporable liquid 132. The evaporation of the liquid in the containment groove 131 brings the humidity inside the internal evaporation prevention cover 4 to saturation and maintains that level, thereby maximizing the reduction of the amount of liquid evaporation in the liquid collection container 1 and further improving measurement accuracy.

[0079] In one embodiment of the housing groove 131, the housing groove 131 may be installed as an annular groove opened in the circumferential direction of the evaporation well 11, and the annular groove is located on the outside of the mounting chamber 14.

[0080] Based on the above embodiment, in order to further reduce the amount of liquid evaporation, as shown in Figure 5, the external evaporation prevention assembly 15 in this embodiment includes an external windbreak cover 6 and an external evaporation prevention cover 10, the external evaporation prevention cover 10 is provided on top of the internal evaporation prevention cover 4, the external windbreak cover 6 is provided covering the outside of the external evaporation prevention cover 10 and the internal evaporation prevention cover 4, the upper end of the capillary receiving tube 8 extends into the external evaporation prevention cover 10, the outlet 70 of the outlet tube 7 penetrates the external windbreak cover 6 and the external evaporation prevention cover 10 in sequence and is aligned horizontally with the liquid receiving port 83, and a first humidity adjustment structure 9 is provided inside the external evaporation prevention cover 10 to increase the humidity inside the external evaporation prevention cover 10. In one embodiment of the first humidity adjustment structure 9, the first humidity adjustment structure 9 includes a moist water-absorbing strip fitted inside the external evaporation prevention cover 10.

[0081] Specifically, in this embodiment, the outer evaporation prevention cover 10 is provided on the upper part of the inner evaporation prevention cover 4 and is located inside the outer windbreak cover 6. The outer evaporation prevention cover 10 covers the portion of the capillary receiving tube 8 that extends from the inner evaporation prevention cover 4, that is, it covers at least the horizontal tube segment 84 of the capillary receiving tube 8. The outlet 70 of the outlet tube 7 penetrates the outer evaporation prevention cover 10, that is, the horizontal outlet segment penetrates the outer evaporation prevention cover 10 and is aligned horizontally with the horizontal tube segment 84. A moist water-absorbing strip is provided inside the outer evaporation prevention cover 10.

[0082] Specifically, the outlet 70 of the outlet tube 7 and the liquid receiving port 83 of the capillary receiving tube 8 do not come into direct contact, and they maintain a predetermined distance from each other. As a result, the liquid to be measured between the outlet 70 and the liquid receiving port 83 comes into contact with the outside air, causing a certain amount of evaporation. Therefore, in this embodiment, an outer evaporation prevention cover 10 is installed on top of the inner evaporation prevention cover 4. The outer evaporation prevention cover 10 covers the outlet 70 and the liquid receiving port 83, and a moist water-absorbing strip is installed inside the outer evaporation prevention cover 10. The liquid contained in the water-absorbing strip can bring the air humidity inside the outer evaporation prevention cover 10 to a stable humidity saturation state. This saturates the air humidity near the outlet 70 and the liquid receiving port 83, reducing the amount of evaporation during the process in which the liquid is drawn into the capillary receiving tube 8 through the liquid receiving port 83, and further improving measurement accuracy.

[0083] Furthermore, in this embodiment, the water-absorbing strip is installed in two places, and the two water-absorbing strips are fitted onto the inner top surface of the outer evaporation prevention cover 10 and the outer top surface of the inner evaporation prevention cover 4, respectively.

[0084] According to another aspect of the present invention, a method for measuring minute flow rates is provided, employing the above-mentioned minute flow rate measuring device, The steps include: pushing the liquid to be measured for flow rate out of the outlet 70 of the outlet pipe 7 to form a slightly convex liquid surface; The steps include using the liquid receiving port 83 of the capillary receiving tube 8 to suck up the liquid pushed out from the outlet port 70 at T1 time intervals, After the liquid first drips from the liquid outlet of the capillary receiving tube 8 into the liquid collection container 1, the reading on the weighing balance 3 is read at each T1 time interval, The process includes the step of determining the liquid flow rate based on the reading of the weighing balance 3 at each T1 hour.

[0085] Specifically, in this embodiment, the liquid to be measured for flow rate is pushed out from the outlet 70 of the outlet pipe 7 to form a slightly convex liquid surface. After the liquid surface comes into contact with the liquid receiving port 83 of the capillary receiving tube 8, it is rapidly drawn in and cut by capillary action and gradually accumulated in the vertical section of the capillary receiving tube 8. After a predetermined mass of liquid has accumulated in the vertical section, the liquid drips from the liquid outlet 82 at the lower end of the vertical section into the liquid collection container 1. Next, the current mass of the liquid collection container 1 can be obtained using the weighing balance 3, and the mass of the dripped liquid can be obtained, thereby allowing the liquid flow rate to be obtained using the mass method. When using the mass method, the liquid flow rate can be calculated by accumulating the readings at each T1.

[0086] In this invention, since there is a gap between the outlet 70 of the outlet pipe 7 and the liquid receiving port 83 of the capillary receiving pipe 8, the liquid pushed out from the outlet 70 needs to form a predetermined micro-convex liquid surface in order to be drawn into the liquid receiving port 83. In this embodiment, time T1 is the sum of the time required to form the micro-convex liquid surface and the time required for the liquid receiving port 83 to draw in the liquid in that portion. Therefore, the specific value of T1 needs to be designed according to the properties of the liquid to be measured for flow rate, the structure of the outlet pipe 7, and the structure of the capillary receiving pipe 8, and this embodiment does not limit the specific numerical value.

[0087] When the micro-flow rate measuring device includes an evaporation well 11 and an outer evaporation prevention cover 10, when measuring the flow rate, first the air humidity inside the inner evaporation prevention cover 4 and the air humidity inside the outer evaporation prevention cover 10 are controlled to set values, and then the liquid to be measured is injected into the outlet pipe 7 to perform the flow rate measurement process. During measurement, the air humidity inside the inner evaporation prevention cover 4 and the air humidity inside the outer evaporation prevention cover 10 can be monitored in real time and controlled simultaneously, and the amount of liquid evaporation during measurement can also be reduced.

[0088] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various modifications and changes to the invention. Any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and principles of the invention should be included within the scope of protection of the present invention. [Explanation of Symbols]

[0089] 1 Liquid collection container, 101 containment cavity, 2 medium to be measured, 3 weighing balance, 4 internal evaporation prevention cover, 5 packing assembly, 50 seal packing, 51 exhaust pipe, 6 external windproof cover, 7 outlet pipe, 70 outlet, 8 capillary receiving pipe, 80 first pipe segment, 801 corner segment, 81 second pipe segment, 82 liquid outlet, 83 liquid receiving port, 84 horizontal pipe segment, 85 vertical pipe segment, 9 first humidity control structure, 10 external evaporation prevention cover, 11 evaporation well, 13 second humidity control structure, 131 containment groove, 132 evaporable liquid, 14 mounting chamber, 15 external evaporation prevention assembly.

Claims

1. A micro-flow rate measuring device based on the mass method, An internal evaporation prevention cover, An outer evaporation prevention assembly is provided covering the aforementioned inner evaporation prevention cover, A weighing balance provided inside the aforementioned internal evaporation prevention cover, A liquid collection container is provided inside the aforementioned internal evaporation prevention cover and placed on the aforementioned weighing balance, A packing assembly provided within the liquid collection container, manufactured from a low water absorption material, breathable, and having a containment cavity between its lower end and the bottom of the liquid collection container for containing the liquid to be measured, It is installed in an L-shape, with a liquid receiving port and a liquid discharge port at both the upper and lower ends, the lower end of which penetrates the packing material assembly vertically and extends into the containment cavity, and the upper end of which penetrates the internal evaporation prevention cover and curves horizontally, A minute flow rate measuring device based on the mass method, comprising a horizontal discharge segment, the end of which of the horizontal discharge segment is provided with a discharge port, the discharge port passing through the external evaporation prevention assembly and being aligned horizontally with the liquid receiving port, and maintaining a first interval, thereby drawing the liquid discharged from the discharge port into the liquid receiving port at intervals, and the liquid outlet causing the liquid to drip into the liquid collection container at intervals.

2. The minute flow rate measuring device based on the mass method according to claim 1, characterized in that the first interval is smaller than the outer diameter of the outlet and larger than the maximum distance required to form a continuous liquid column between the outlet and the liquid receiving port.

3. The minute flow rate measuring device based on the mass method according to claim 2, characterized in that the first interval is smaller than half the outer diameter of the outlet.

4. A conical structure is installed at the end of the horizontal outlet segment of the outlet pipe closest to the capillary receiving tube, and the outer diameter of the end of the conical structure closest to the capillary receiving tube is equal to the inner diameter of the liquid receiving opening. The minute flow rate measuring device based on the mass method according to claim 2, characterized in that the first interval is the interval between the end of the conical structure closest to the capillary receiving tube and the end of the liquid receiving port.

5. The capillary receiving tube includes a first tube segment and a second tube segment communicating with each other, the inner diameter of the second tube segment being larger than the inner diameter of the first tube segment, the second tube segment extending vertically through the packing assembly into the containment cavity, and the liquid outlet located at the lower end of the second tube segment. The minute flow rate measuring device based on the mass method according to claim 1, characterized in that the first pipe segment includes one horizontal segment, and the liquid receiving port is located at the end of the horizontal segment.

6. The minute flow rate measuring device based on the mass method according to claim 5, characterized in that the first pipe segment and the second pipe segment are connected via a transition segment, the transition segment is installed in a conical shape, the small diameter end of the transition segment is connected to the first pipe segment, and the large diameter end of the transition segment is connected to the second pipe segment.

7. The microflow rate measuring device based on the mass method according to claim 1, characterized in that the packing material assembly is one or more of polyamide, polyethylene, and polypropylene polymer materials having micropores.

8. The minute flow rate measuring device based on the mass method according to claim 1, wherein the packing assembly includes a seal packing material and an exhaust pipe, the seal packing material is made of a low water absorption material, and the exhaust pipe penetrates the seal packing material.

9. The minute flow rate measuring device based on the mass method according to claim 8, characterized in that the inner diameter of the exhaust pipe is smaller than the inner diameter of the outlet pipe.

10. The seal filler material is elastic, and the seal filler material is inserted and fixed inside the liquid collection container. The minute flow rate measuring device based on the mass method according to claim 8 or 9, characterized in that the seal filling material is provided with through holes and mounting holes, the capillary receiving tube is fitted tightly through the through holes, and the exhaust pipe is fitted tightly through the mounting holes.

11. The minute flow rate measuring device based on the mass method according to claim 10, characterized in that a plurality of mounting holes are provided, the exhaust pipe is provided in at least one of the mounting holes, and a removable seal plug is provided in the other mounting holes.

12. The minute flow rate measuring device based on the mass method according to claim 11, characterized in that the seal plug is manufactured from a low water absorption material and the lower end surface of the seal plug is flush with the lower end surface of the seal filler.

13. The minute flow rate measuring device based on the mass method according to claim 1, characterized in that the distance between the liquid outlet and the inner bottom surface of the liquid collection container is greater than the height of the liquid in the containment cavity during measurement.

14. The external evaporation prevention assembly includes an external windproof cover and an external evaporation prevention cover, the external evaporation prevention cover being provided on top of the internal evaporation prevention cover, and the external windproof cover being provided to cover the outside of the external evaporation prevention cover and the internal evaporation prevention cover. The upper end of the capillary receiving tube extends into the outer evaporation prevention cover, and the outlet of the liquid outlet tube passes through the outer windproof cover and the outer evaporation prevention cover in sequence, and is positioned horizontally with the liquid receiving port. The minute flow rate measuring device based on the mass method according to claim 1, characterized in that a first humidity adjustment structure for increasing the humidity inside the external evaporation prevention cover is provided inside the external evaporation prevention cover.

15. The minute flow rate measuring device based on the mass method according to claim 14, characterized in that the first humidity control structure includes a moist water-absorbing strip fitted inside the external evaporation prevention cover.

16. The minute flow rate measuring device further includes an evaporation well, the evaporation well is provided within the internal evaporation prevention cover, and an axially penetrating mounting chamber is provided inside the evaporation well, the mounting chamber is fitted to the outside of the liquid collection container and the weighing balance, and there is a radial gap between the liquid collection container and the weighing balance. The minute flow rate measuring device based on the mass method according to claim 14, characterized in that the evaporation well is provided with a second humidity adjustment structure for increasing the humidity inside the mounting chamber.

17. The minute flow rate measuring device based on the mass method according to claim 16, characterized in that the second humidity control structure includes a containment groove opened at the upper end of the evaporation well, and an evaporable liquid is contained in the containment groove.

18. A method for measuring minute flow rates, employing a minute flow rate measuring device described in any one of claims 1 to 17, The steps include: pushing the liquid to be measured for flow rate out of the outlet of the outlet pipe to form a slightly convex liquid surface; Using the liquid receiving port of the capillary receiving tube, T １ A step of sucking up the liquid that is pushed out from the outlet at time intervals, After the liquid first drips from the liquid outlet of the capillary receiving tube into the liquid collection container, each T １ The steps include reading the reading of the weighing balance at time intervals, Each T １ A method for measuring minute flow rates, characterized by comprising the step of determining the liquid flow rate based on the reading of the weighing balance over time.

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