Mass flowmeter

Abstract

The invention provides a mass flow meter which comprises a housing and a flow meter body arranged in the housing, and two groups of pipelines which are connected with the flow meter body and used for liquid inlet and outlet are fixed on the housing through a thermal bridge structure; the heat bridge structure seals the space between the outer wall of the pipeline and the housing, and the heat bridge structure extends in a reciprocating mode in the axial direction of the pipeline so as to prolong a heat transfer path between the pipeline and the housing; according to the mass flow meter, the thermal bridge structure is connected between the outer wall of the pipeline and the housing in a sealed mode, and the pipeline in the housing and the flow meter body can be isolated from the external environment; besides, the heat bridge structure extends in a reciprocating mode in the axial direction of the pipeline, a heat transfer path between the housing and the pipeline can be increased, the phenomenon that low-temperature liquid in the pipeline is gasified due to heat transferred by the housing can be reduced, and the measuring precision of the flowmeter is improved; and meanwhile, the frosting of the housing can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of flow measurement equipment, in particular to a mass flow meter. Background Art

[0002] For flow detection of ultra-low temperature liquids such as liquid hydrogen, in the current conventional Coriolis flowmeter, the cover of the flowmeter is directly connected to the liquid inlet and outlet components. The low-temperature liquid inside the liquid inlet and outlet components will transfer the cold directly to the cover, which will cause serious frosting of the cover; at the same time, due to the large heat exchange area between the cover and the outside world, the heat loss is serious, which will cause the liquid hydrogen in the leaching liquid component and the measuring pipeline to appear more serious gasification phenomenon, affecting the measurement accuracy of the flowmeter. Summary of the invention

[0003] The object of the present invention is to overcome the shortcomings of the background technology and provide a mass flow meter that can be used to accurately measure the flow rate of cryogenic liquid media, wherein the cryogenic liquid media includes but is not limited to liquid hydrogen, liquid nitrogen, liquid ammonia and liquid oxygen.

[0004] The embodiments of the present invention are implemented by the following technical solutions:

[0005] A mass flow meter comprises a housing and a flow meter body arranged inside the housing, and two groups of pipes connected to the flow meter body for inlet and outlet of liquid are fixed to the housing through a thermal bridge structure;

[0006] The thermal bridge structure seals between the outer wall of the pipe and the casing, and the thermal bridge structure reciprocates along the axial direction of the pipe to extend the heat transfer path between the pipe and the casing.

[0007] Furthermore, the thermal bridge structure is located inside the cover shell.

[0008] Furthermore, the thermal bridge structure includes several layers of tubular members sleeved on the pipeline; in the axial direction of the pipeline, the interlayer between any two adjacent layers of the tubular members has one end closed, and the closed ends of any two adjacent layers of the interlayer are in opposite positions.

[0009] Furthermore, the interlayer between the pipeline and the innermost tubular member in the thermal bridge structure is closed by a joint, and the joint serves as a part of the thermal bridge structure and also serves to fix the outer end of the pipeline;

[0010] The joint is located outside the housing, and the joint is connected to the pipeline to transport a medium.

[0011] Furthermore, the thermal bridge structure includes a first tubular member sleeved on the outer peripheral side of the pipeline and a second tubular member sleeved on the outer peripheral side of the first tubular member;

[0012] One end of the second tubular member is closed and connected to the casing, and the other end located inside the casing is closed and connected to the first tubular member; the other end of the first tubular member extends to the outside of the casing and is closed and connected to the joint.

[0013] Furthermore, the joint is coaxially provided with a convex annular first connecting portion and a second connecting portion, and the second connecting portion is located on the outer peripheral side of the first connecting portion;

[0014] Wherein, the first connection part is connected to the pipeline, and the second connection part is connected to the innermost tubular member in the thermal bridge structure.

[0015] Furthermore, the pipeline is arranged in a curved and circuitous shape in the housing to compensate for stress deformation of the pipeline.

[0016] Furthermore, the pipeline is arranged in a "Z" shape.

[0017] Furthermore, the flow meter body comprises a dual-channel measuring tube and a diverter, the dual-channel measuring tube is bent in the housing to form a triangular structure, and two ends of the dual-channel measuring tube are installed on the diverter in a gathered state.

[0018] Furthermore, the diverter has two groups of three-way flow paths, wherein the first group of pipelines is connected to one end of the dual-channel measuring tube through the first group of three-way flow paths, and the second group of pipelines is connected to the other end of the dual-channel measuring tube through the second group of three-way flow paths.

[0019] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0020] In the mass flowmeter of the present invention, the pipeline for liquid inlet and outlet of the flowmeter body is fixed on the cover shell by a thermal bridge structure. The thermal bridge structure is sealed between the outer wall of the pipeline and the cover shell, and the pipeline inside the cover shell and the flowmeter body can be isolated from the external environment. In addition, the thermal bridge structure extends back and forth along the axial direction of the pipeline, which increases the heat transfer path between the cover shell and the pipeline, and can reduce or avoid the vaporization phenomenon of low-temperature liquid inside the pipeline, thereby improving the measurement accuracy of the flowmeter. At the same time, it can also reduce frosting of the cover shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The internal structure of the mass flow meter of the embodiment of the present invention is shown in FIG. Figure 1 ;

[0022] Figure 2 The internal structure of the mass flow meter of the embodiment of the present invention is shown in FIG. Figure 2 ;

[0023] Figure 3 for Figure 2 An enlarged view of part A in FIG.

[0024] Icons: 1-cover, 2-flowmeter body, 20-diverter, 200-three-way flow path, 21-dual-channel measuring tube, 3-pipeline, 4-thermal bridge structure, 40-tubular part, 400-first tubular part, 401-second tubular part, 41-interlayer, 42-sealing structure, 5-joint, 50-first connecting part, 51-second connecting part. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Reference Figures 1 to 3 A mass flowmeter includes a cover 1 and a flowmeter body 2 arranged inside the cover 1, the flowmeter body 2 is connected to the external environment of the cover 1 through two groups of pipes 3, wherein one group of pipes 3 is used for liquid inlet of the flowmeter body 2 and the other group of pipes 3 is used for liquid outlet of the flowmeter body 2.

[0027] In order to solve the problem of frosting of the cover 1 and the heat transfer between the cover 1 and the pipeline 3 causing the liquid in the pipeline 3 to be easily vaporized, in the present invention, a thermal bridge 4 is added between the cover 1 and the pipeline 3 to reduce the heat transfer between the cover 1 and the pipeline 3; specifically, the above-mentioned two groups of pipelines 3 are fixed to the cover 1 through the thermal bridge structure 4, so as to distinguish from the situation in which the pipelines in the traditional flow meter are directly welded and fixed to the cover.

[0028] Reference Figure 1 and Figure 3 In fact, the thermal bridge structure 4 is sealed between the outer wall of the pipe 3 and the housing 1, so that the interior of the housing 1 is isolated from the external environment.

[0029] Among them, the thermal bridge structure 4 extends back and forth along the axial direction of the pipe 3 to extend the heat transfer path between the pipe 3 and the cover 1. Therefore, the thermal bridge structure 4 can adopt a ripple structure similar to the water surface. The thermal bridge structure 4 spreads to the surrounding areas with the pipe 3 as the ripple center and is connected to the cover 1 on the surrounding side.

[0030] Reference Figure 3In this embodiment, in order to further extend the heat transfer path of the thermal bridge structure 4, the thermal bridge structure 4 includes several layers of tubular members 40 sleeved on the pipeline 3, and in the axial direction or length extension direction of the pipeline 3, the interlayer 41 between any two adjacent layers of tubular members 40 has one end closed, and the closed ends of any two adjacent layers of interlayer 41 are in opposite positions. Therefore, during the heat transfer process, the heat needs to be continuously transferred through the pipe walls of the several layers of the aforementioned tubular members 40.

[0031] It is easy to understand that the tubular member 40 can be a circular tube, or a pipe with a triangular, quadrilateral, pentagonal or other irregular shapes in cross section. In this embodiment, several tubular members 40 are all circular tube structures.

[0032] Among them, the thermal bridge structure 4 can be located entirely outside the cover 1, or the thermal bridge structure 4 can be located partially outside the cover 1 and partially inside the cover 1; in this embodiment, the thermal bridge structure 4 is located inside the cover 1, which can reduce the thermal contact between the heat transfer structure 4 and the external environment, and further reduce the heat transfer to the pipeline 3.

[0033] Reference Figure 2 and Figure 3 In this embodiment, the thermal bridge structure 4 has two groups of tubular members 40 , that is, the thermal bridge structure 4 includes a first tubular member 400 sleeved on the outer peripheral side of the pipeline 3 , and a second tubular member 401 sleeved on the outer peripheral side of the first tubular member 400 .

[0034] Reference Figure 3 , wherein one outer end of the second tubular member 401 is closed and connected to the cover shell 1, and the other end of the second tubular member 401 located inside the cover shell 1 is closed and connected to the first tubular member 400, and the closing method is a sealing structure 42 arranged between the outer wall of the end of the first tubular member 400 and the inner wall of the end of the second tubular member 401; one outer end of the first tubular member 400 extends to the outside of the cover shell 1 and is closed and connected to the joint 5.

[0035] Reference Figure 3 , the joint 5 is located on the outside of the cover 1, and the function of the joint 5 is to connect with the pipeline 3 to transport the liquid medium; wherein, a convex annular first connection part 50 and a second connection part 51 are coaxially arranged on the joint 5, and the second connection part 51 is located on the outer peripheral side of the first connection part 50, wherein the protruding length of the first connection part 50 is greater than the protruding length of the second connection part 51, the first connection part 50 is connected to the pipeline 3, and the second connection part 51 is connected to the innermost tubular member 40 in the thermal bridge structure 4, that is, in this embodiment, the second connection part 51 is connected to the outer end of the first tubular member 400.

[0036] Therefore, the joint 5 in this embodiment can be used as a part of the thermal bridge structure 4 for heat transfer, and the joint 5 can also fix the outer end of the pipe 3; the heat transfer path is increased by the thermal bridge 4, the heat transfer between the pipe 3 and the cover 1 is limited, and the cover 1 will not frost due to low temperature.

[0037] Reference Figure 1 and Figure 2 The flowmeter body 2 includes a dual-channel measuring tube 21 and a diverter 20. The dual-channel measuring tube 21 includes two sets of parallel pipeline flow paths. In the cover 1, the dual-channel measuring tube 21 is bent into a triangular structure, and the two ends of the dual-channel measuring tube 21 are installed on the diverter 20 in a gathered state.

[0038] Among them, there are two groups of three-way flow paths 200 in the diverter 20, wherein the first group of pipelines 3 is connected to one end of the dual-channel measuring tube 21 through the first group of three-way flow paths 200, and the second group of pipelines 3 is connected to the other end of the dual-channel measuring tube 21 through the second group of three-way flow paths 200, that is, the liquid medium enters the diverter 20 along one group of pipelines 3 and is diverted to the dual-channel measuring tube 21, and the liquid medium flowing out of the dual-channel measuring tube 21 is converged to the other group of pipelines 3 through the diverter 20 for discharge.

[0039] The dual-channel measuring tube 21 is provided with corresponding detection components. When the liquid medium flows in the dual-channel measuring tube 21, a Coriolis force proportional to the mass flow rate will be generated. This force will cause the dual-channel measuring tube 21 to vibrate torsional, and the detection coils installed at both ends of the dual-channel measuring tube 21 will generate signals with different phases. The phase difference between the two signals is proportional to the mass flow rate of the fluid flowing through the sensor. By measuring these phase differences, the mass flow rate of the fluid can be calculated. The structural principle is the existing technology and will not be repeated here.

[0040] In addition, when the liquid medium flows through the internal parts of the cover 1 such as the joint 5, the pipe 3 and the diverter 20, the above-mentioned parts will shrink because they are in direct contact with the liquid medium. At the same time, the temperature of the cover 1 is relatively high, which is inconsistent with the shrinkage of the structure of the above-mentioned internal parts, which will hinder the shrinkage. Therefore, the pipe 3 is more likely to shrink and deform along the direction of stress.

[0041] Therefore, in order to solve the problem of excessive shrinkage stress and deformation of the pipeline 3 under ultra-low temperature, the pipeline 3 is arranged in a curved and circuitous shape in the housing 1 to compensate for the stress deformation of the pipeline 3.

[0042] Reference Figure 1 and Figure 2In this embodiment, the pipeline 3 is arranged in a "Z" shape, so that the material of the pipeline 3 meets the shrinkage stress requirements of the pipeline 3 at low temperatures, eliminating the influence of excessive stress on the performance of the flow meter. At this time, the stress is mainly concentrated at the bend of the "Z"-shaped pipeline 3, so the pipeline 3 has the ability to compensate for deformation without affecting the measurement accuracy and damaging the equipment.

[0043] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A mass flow meter, comprising a housing (1) and a flow meter body (2) arranged inside the housing (1), two groups of pipes (3) connected to the flow meter body (2) for inlet and outlet of liquid are fixed to the housing (1) through a thermal bridge structure (4), characterized in that: The thermal bridge structure (4) seals between the outer wall of the pipe (3) and the casing (1), and the thermal bridge structure (4) extends reciprocatingly along the axial direction of the pipe (3) to extend the heat transfer path between the pipe (3) and the casing (1).

2. The mass flow meter according to claim 1, characterized in that: The thermal bridge structure (4) is located inside the cover shell (1).

3. The mass flow meter according to claim 2, characterized in that: The thermal bridge structure (4) comprises a plurality of layers of tubular members (40) sleeved on the pipe (3); in the axial direction of the pipe (3), one end of the interlayer (41) between any two adjacent layers of the tubular members (40) is closed, and the closed ends of any two adjacent layers of the interlayer (41) are in opposite positions.

4. The mass flow meter according to claim 3, characterized in that: The interlayer (41) between the pipe (3) and the innermost tubular member (40) in the thermal bridge structure (4) is closed by a joint (5); The joint (5) is located outside the housing (1), and the joint (5) is connected to the pipeline (3) to transport the medium.

5. The mass flow meter according to claim 4, characterized in that: The thermal bridge structure (4) comprises a first tubular member (400) sleeved on the outer peripheral side of the pipeline (3) and a second tubular member (401) sleeved on the outer peripheral side of the first tubular member (400); One end of the second tubular member (401) is closed and connected to the casing (1), and the other end located inside the casing (1) is closed and connected to the first tubular member (400); the other end of the first tubular member (400) extends to the outside of the casing (1) and is closed and connected to the joint (5).

6. The mass flow meter according to claim 4 or 5, characterized in that: The joint (5) is coaxially provided with a convex annular first connecting portion (50) and a second connecting portion (51), and the second connecting portion (51) is located on the outer peripheral side of the first connecting portion (50); The first connection portion (50) is connected to the pipeline (3), and the second connection portion (51) is connected to the innermost tubular member (40) in the thermal bridge structure (4).

7. The mass flow meter according to any one of claims 1 to 5, characterized in that: The pipeline (3) is arranged in a curved and circuitous manner inside the housing (1) to compensate for stress deformation of the pipeline (3).

8. The mass flow meter according to claim 7, characterized in that: The pipeline (3) is arranged in a "Z" shape.

9. The mass flow meter according to any one of claims 1 to 5, characterized in that: The flow meter body (2) comprises a dual-channel measuring tube (21) and a flow divider (20); the dual-channel measuring tube (21) is bent in the housing (1) to form a triangular structure, and both ends of the dual-channel measuring tube (21) are mounted on the flow divider (20) in a gathered state.

10. The mass flow meter according to any one of claims 1 to 9, characterized in that The flow divider (20) has two sets of three-way flow paths (200); The first group of pipelines (3) are connected to one end of the dual-channel measuring tube (21) through the first group of three-way flow paths (200), and the second group of pipelines (3) are connected to the other end of the dual-channel measuring tube (21) through the second group of three-way flow paths (200).

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