Liquid level tracking liquid mass weighing method and apparatus

Abstract

The present application relates to the technical field of micro liquid flow standard device, more particularly, it is especially related to a liquid surface tracking type liquid mass weighing method and device.The present application comprises: S1, using a spectral confocal sensor to monitor the liquid level in the weighing container in real time; S2, driving the liquid inlet pipe by a motor control module, so that the lower end of the liquid inlet pipe keeps a constant relative position with the liquid level; S3, continuously recording the liquid mass by a weighing device; S4, using the constant relative position to regard the surface tension as a system constant, and deducting the weighing initial value to eliminate the influence of the surface tension on the dynamic weighing uncertainty.The present application can keep the distance between the liquid surface and the liquid injection pipe constant, and the error is controlled within 0.5mm, so that the surface tension becomes a stable system error and is eliminated, and the influence of the surface tension on the micro liquid mass weighing uncertainty is eliminated.

Description

Technical Field

[0001] This invention relates to the field of micro-liquid flow rate standard devices, and more specifically, to a liquid level tracking liquid mass weighing method and device. Background Technology

[0002] During the dynamic weighing of small liquid flow rates, the buoyancy changes and outlet pressure fluctuations are caused by the pipe being submerged in the liquid surface and the depth gradually increasing. In addition, there is a surface tension between the pipe and the liquid surface. Under the condition of small liquid flow rates, these factors will have a significant impact on the actual weighing value.

[0003] Existing technologies cannot dynamically weigh minute liquid flow rates within a given range. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the objective of this invention is to propose a liquid level tracking liquid mass weighing method and apparatus, enabling dynamic weighing of minute liquid flow rates within a wide flow range, and effectively reducing the impact of surface tension changes on weighing uncertainty.

[0005] To achieve the above and other related objectives, the present invention provides a liquid level tracking liquid mass weighing method, comprising: S1. Use a spectral confocal sensor to monitor the liquid level in the weighing container in real time; S2. Drive the liquid inlet pipe through the motor control module to keep the lower end of the liquid inlet pipe in a constant relative position with the liquid surface; S3. Continuously record the mass of the liquid using a weighing device; S4. By using a constant relative position to treat surface tension as a system constant, the initial value of the weighing is subtracted to eliminate the influence of surface tension on the uncertainty of dynamic weighing.

[0006] In one embodiment of the present invention, the distance error between the lower end of the liquid inlet pipe and the liquid surface in step S2 is ≤ ±0.05 mm.

[0007] In one embodiment of the present invention, the continuous recording of liquid mass by weighing device in step S3 is achieved within a flow rate range of 0.0003~0.003 m3 / h.

[0008] In one embodiment of the present invention, the motor control module includes a motor and a lead screw mechanism.

[0009] In one embodiment of the present invention, the liquid inlet pipe, the spectral confocal sensor, and the outer side of the container are provided with a windproof cover.

[0010] In one embodiment of the present invention, step S4, which utilizes the constant relative position to treat surface tension as a system constant and subtracts the initial value of the weighing to eliminate the influence of surface tension on the uncertainty of dynamic weighing, includes: According to the surface tension calculation formula: , Where σ is the surface tension between the pipe and the water, which is constant. Therefore, the surface tension changes with the cosine of the contact angle θ. The change of θ is negligible. The surface tension is a constant value, that is, the surface tension of the initial value recorded by the weighing equipment is consistent. Thus, the weighing mass within the measurement period is free from the influence of surface tension.

[0011] In one embodiment of the present invention, the weighing device is an electronic balance.

[0012] In one embodiment of the present invention, a concave meniscus is formed between the liquid inlet pipe and the liquid surface.

[0013] The present invention also provides a liquid level tracking liquid mass weighing device, comprising: A spectral confocal sensor is used to monitor the liquid level in a weighing container in real time. The motor control module is used to drive the liquid inlet pipe so that the lower end of the liquid inlet pipe maintains a constant relative position with the liquid surface. Weighing equipment is used to continuously record the mass of liquids and uses the constant relative position to treat surface tension as a system constant, subtracting the initial value of the weighing to eliminate the influence of surface tension on the uncertainty of dynamic weighing.

[0014] As described above, the liquid level tracking liquid mass weighing method and apparatus of the present invention has the following beneficial effects: The present invention provides a liquid level tracking liquid mass weighing method that can achieve dynamic weighing of small liquid flow rates within the range of (0.0003~0.003) m3 / h, and effectively reduce the influence of surface tension changes on the weighing uncertainty.

[0015] The present invention provides a liquid level tracking liquid mass weighing method that can achieve a constant distance between the liquid level and the injection tube, and control the error within 0.5 mm, thereby transforming surface tension into a stable systematic error and eliminating it, thus eliminating its influence on the uncertainty of small liquid mass weighing.

[0016] The present invention provides a liquid level tracking liquid mass weighing method that calculates and corrects the speed of the injection pipe motor in real time to ensure that the position of the inlet pipe relative to the liquid surface is constant and the error does not exceed 0.5 mm. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the liquid film on the liquid surface of the inlet pipe in a liquid level tracking liquid mass weighing method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of an experimental test of motor control for a liquid level tracking liquid mass weighing method according to an embodiment of the present invention. Detailed Implementation

[0018] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0020] Terms such as "first" or "second" may be used to describe various components, but these components are not limited by the terms described above. The terms described above are used to distinguish one component from another; for example, without departing from the scope of the concept according to this disclosure, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

[0021] Furthermore, "connected / linked" indicates that one component is directly electrically connected to another component or indirectly electrically connected through another component. Unless otherwise explicitly stated in the sentence, the singular form may include the plural form. Additionally, the terms "comprising / including" or "containing / including" as used in this specification indicate the presence or addition of one or more components, steps, operations, and elements. Specific structural or functional descriptions of examples of embodiments of the concepts disclosed in this specification are merely illustrative to describe examples of embodiments of the concepts, and examples of embodiments of the concepts can be implemented in various forms, but these descriptions are not limited to the examples of embodiments described in this specification.

[0022] Based on the concept, various modifications and changes can be applied to examples of embodiments, such that examples of embodiments will be illustrated in the accompanying drawings and described in the specification. However, examples of embodiments based on the concept are not limited to specific embodiments, but include all changes, equivalents, or substitutions included within the spirit and scope of this disclosure.

[0023] It should be understood that when describing an element as "connected" or "linked" to another element, the element may be directly connected or linked to the other element, or it may be connected or linked to the other element via a third element. Conversely, it should be understood that when an element is described as "directly connected to" or "directly linked to" another element, no other element is placed between them. Other expressions describing relationships between components (i.e., "between" and "directly between" or "adjacent to" and "directly adjacent to") need to be interpreted in the same way.

[0024] The terminology used in this specification is for the purpose of describing specific examples of implementations only and is not intended to limit this disclosure. The singular form may include the plural form unless there is an explicit contrary meaning in the context. It should be understood in this specification that the terms "comprising" or "having" indicate the presence of the features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts, or combinations thereof.

[0025] Unless otherwise defined, all terms used herein (including technical or scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art. If a term is not clearly defined in a common dictionary in this specification, it shall be interpreted as having the same meaning as in the context of the relevant art, and not as an ideal or overly formal meaning.

[0026] Descriptions of known components and processing techniques may be omitted to avoid unnecessarily obscuring the embodiments of this disclosure.

[0027] Throughout this specification, the same reference numerals refer to the same elements. Therefore, even if a reference numeral is not mentioned or described with reference to one drawing, it may be mentioned or described with reference to another drawing. Furthermore, even if a reference numeral is not shown in one drawing, it may be mentioned or described with reference to another drawing.

[0028] Additionally, the logic level of a signal may be different from or opposite to the logic level described. For example, a signal described as having a logic "high" level may optionally have a logic "low" level, and a signal described as having a logic "low" level may optionally have a logic "high" level.

[0029] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0030] Please see Figure 1 , Figure 2 , Figure 1 This is a schematic diagram of the liquid film on the liquid surface of the inlet pipe in a liquid level tracking liquid mass weighing method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a motor control experiment for a liquid level tracking liquid mass weighing method according to an embodiment of the present invention. The present invention provides a liquid level tracking liquid mass weighing method, comprising: S1. Use a spectral confocal sensor to monitor the liquid level in the weighing container in real time; S2. Drive the liquid inlet pipe through the motor control module to keep the lower end of the liquid inlet pipe in a constant relative position with the liquid surface; S3. Continuously record the mass of the liquid using a weighing device; S4. By using a constant relative position to treat surface tension as a system constant, the initial value of the weighing is subtracted to eliminate the influence of surface tension on the uncertainty of dynamic weighing.

[0031] In one embodiment of the present invention, by working together with a high sampling rate electronic balance and a spectral confocal sensor, a liquid mass weighing technology that reduces the impact of dynamic effects is achieved within a flow rate range of (0.0003~0.003) m³ / h. This reduces the impact of dynamic effects such as liquid surface fluctuations and surface tension fluctuations, thereby improving the stability and accuracy of weighing small flow liquids.

[0032] In one embodiment of the present invention, the dynamic mass method liquid flow device with a constant relative position between the inlet pipe and the liquid surface uses a spectral confocal sensor to monitor the liquid level height. The motor controls the movement speed of the lead screw and the inlet pipe, and the relative position between the inlet pipe and the liquid surface height remains unchanged. The liquid surface distance error is controlled within ±0.05mm, which can ensure that the liquid surface and the inlet pipe are always connected by a concave meniscus liquid surface.

[0033] Specifically, in step S2, the distance error between the lower end of the inlet pipe and the liquid surface is ≤ ±0.05 mm.

[0034] Specifically, the continuous recording of liquid mass by weighing equipment in step S3 is achieved within a flow rate range of 0.0003~0.003 m3 / h.

[0035] Specifically, the motor control module includes a motor and a lead screw mechanism.

[0036] Specifically, the inlet pipe, the spectral confocal sensor, and the outside of the container are equipped with windproof covers.

[0037] Specifically, step S4, which treats surface tension as a system constant using a constant relative position and subtracts the initial value of the weighing to eliminate the influence of surface tension on the uncertainty of dynamic weighing, includes: According to the surface tension calculation formula: , Where σ is the surface tension between the pipe and the water, which is constant. Therefore, the surface tension changes with the cosine of the contact angle θ. The change of θ is negligible. The surface tension is a constant value, that is, the surface tension of the initial value recorded by the weighing equipment is consistent. Thus, the weighing mass within the measurement period is free from the influence of surface tension.

[0038] Specifically, the weighing device is an electronic balance. A concave meniscus is formed between the liquid inlet pipe and the liquid surface.

[0039] The present invention also provides a liquid level tracking liquid mass weighing device, comprising: A spectral confocal sensor is used to monitor the liquid level in a weighing container in real time. The motor control module is used to drive the liquid inlet pipe so that the lower end of the liquid inlet pipe maintains a constant relative position with the liquid surface. Weighing equipment is used to continuously record the mass of liquids and uses the constant relative position to treat surface tension as a system constant, subtracting the initial value of the weighing to eliminate the influence of surface tension on the uncertainty of dynamic weighing.

[0040] In one embodiment of the present invention, the main interaction between the inlet pipe and the liquid surface is surface tension. Since the positions of the pipe and the liquid surface are relatively fixed, and the absolute value of the relative positional error does not exceed 0.05 mm, the surface tension is calculated using the formula... Here, σ represents the surface tension between the pipe and the water, which is constant. Therefore, the surface tension changes with the cosine of the contact angle θ. The change in θ is negligible. The magnitude of θ is related to temperature, humidity, pressure, and changes in the contact surface. During the experiment, changes in the contact surface between the pipe and the liquid surface cause changes in the surface tension, which will have a certain impact on the actual weighing value. The relative position change range between the inlet pipe and the liquid surface is ±0.05mm, and the change in θ is negligible. Therefore, the surface tension is considered to be a constant value, that is, the surface tension of the initial values ​​recorded by the weighing equipment is consistent. Thus, the weighing mass during the measurement period eliminates the influence of surface tension.

[0041] In one embodiment of the present invention, an electronic balance, a spectral confocal sensor, and a liquid injection tube control motor work together to weigh a small amount of liquid.

[0042] In one embodiment of the present invention, the distance between the injection tube and the liquid surface is set and adjusted to a set position by a motor.

[0043] In one embodiment of the present invention, the flow rate is set, the motor speed is calculated and assigned a value.

[0044] In summary, the liquid level tracking liquid mass weighing method of the present invention can achieve dynamic weighing of minute liquid flow rates within the range of (0.0003~0.003) m³ / h, and effectively reduce the influence of surface tension changes on the weighing uncertainty. The present invention can maintain a constant distance between the liquid surface and the injection pipe, with the error controlled within 0.5 mm, thereby transforming surface tension into a stable systematic error and eliminating it, thus eliminating its influence on the weighing uncertainty of minute liquid flows.

[0045] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A liquid level tracking method for liquid mass weighing, characterized in that, include: S1. Use a spectral confocal sensor to monitor the liquid level in the weighing container in real time; S2. Drive the liquid inlet pipe through the motor control module to keep the lower end of the liquid inlet pipe in a constant relative position with the liquid surface; S3. Continuously record the mass of the liquid using a weighing device; S4. By using a constant relative position to treat surface tension as a system constant, the initial value of the weighing is subtracted to eliminate the influence of surface tension on the uncertainty of dynamic weighing.

2. The liquid level tracking liquid mass weighing method according to claim 1, characterized in that, The distance error between the lower end of the inlet pipe and the liquid surface in step S2 is ≤ ±0.05 mm.

3. The liquid level tracking liquid mass weighing method according to claim 1, characterized in that, The continuous recording of liquid mass by weighing equipment in step S3 is achieved within a flow rate range of 0.0003~0.003 m3 / h.

4. The liquid level tracking liquid mass weighing method according to claim 1, characterized in that, The motor control module includes a motor and a lead screw mechanism.

5. The liquid level tracking liquid mass weighing method according to claim 1, characterized in that, The inlet pipe, the spectral confocal sensor, and the outside of the container are all equipped with windproof covers.

6. The liquid level tracking liquid mass weighing method according to claim 2, characterized in that, Step S4, which treats surface tension as a system constant by utilizing a constant relative position and subtracts the initial value of the weighing to eliminate the influence of surface tension on the dynamic weighing uncertainty, includes: According to the surface tension calculation formula: ， Where σ is the surface tension between the pipe and the water, which is constant. Therefore, the surface tension changes with the cosine of the contact angle θ. The change of θ is negligible. The surface tension is a constant value, that is, the surface tension of the initial value recorded by the weighing equipment is consistent. Thus, the weighing mass within the measurement period is free from the influence of surface tension.

7. A liquid level tracking liquid mass weighing method according to claim 6, characterized in that, The weighing device is an electronic balance.

8. The liquid level tracking liquid mass weighing method according to claim 1, characterized in that, The inlet pipe forms a concave meniscus with the liquid surface.

9. A liquid level tracking liquid mass weighing device, characterized in that, include: A spectral confocal sensor is used to monitor the liquid level in a weighing container in real time. The motor control module is used to drive the liquid inlet pipe so that the lower end of the liquid inlet pipe maintains a constant relative position with the liquid surface. Weighing equipment is used to continuously record the mass of liquids and uses the constant relative position to treat surface tension as a system constant, subtracting the initial value of the weighing to eliminate the influence of surface tension on the uncertainty of dynamic weighing.

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