Low temperature liquid mass flowmeter

Abstract

The application discloses a low-temperature liquid mass flowmeter, and belongs to the Coriolis force mass flowmeter field, which comprises a measuring device, a heat preservation structure arranged outside the measuring device and a stress compensation device connected with the measuring device. The application can solve the problem that the existing mass flowmeter is not applicable to measuring low-temperature liquid.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of Coriolis mass flowmeter, and particularly relates to a low-temperature liquid mass flowmeter. BACKGROUND

[0002] Coriolis mass flowmeter, also known as Coriolis flowmeter, is a device for directly measuring mass flow by using the Coriolis force generated by fluid flowing in a vibrating mother sleeve in proportion to mass flow, which is composed of a flow detection element and a converter. The Coriolis mass flowmeter realizes direct measurement of mass flow, has high precision, can measure multiple media and multiple process parameters, and is widely used in petrochemical, pharmaceutical, food and other industries.

[0003] The inventor found in the actual use process that the prior art at least has the following technical problems:

[0004] The existing Coriolis mass flowmeter is not suitable for measuring low-temperature liquid, and no heat preservation structure is provided, which is easy to cause the vaporization of low-temperature liquid, and under low-temperature conditions, the material of the mass flowmeter shrinks to generate a large stress, which affects the test precision. SUMMARY

[0005] In order to overcome the above-mentioned problems, the inventor of the present application has made long-term exploration and attempts, and through repeated experiments and efforts, continuous reform and innovation, and finally proposed a low-temperature liquid mass flowmeter, which can solve the problem that the existing mass flowmeter is not suitable for measuring low-temperature liquid.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is to provide a low-temperature liquid mass flowmeter, which comprises a measuring device, a heat preservation structure arranged outside the measuring device, and a stress compensation device connected with the measuring device.

[0007] According to the low-temperature liquid mass flowmeter, the further preferred technical scheme is that the measuring device comprises a mother sleeve and a shunt, the mother sleeve is connected with the shunt through an interface,

[0008] According to the low-temperature liquid mass flowmeter, the further preferred technical scheme is that the heat preservation structure comprises a cover shell, which is divided into a first cover shell covering the pipeline outside and a second cover shell covering the shunt; a flange, one end of the flange is connected with the interface, and the other end seals the first cover shell, and the pipeline is sleeved in the flange and connected with the interface through the flange.

[0009] The low-temperature liquid mass flowmeter further has the following preferred technical solutions: the flange comprises a male flange and a female flange, the female flange comprises a female connector connected to the interface, a female flange disc sleeved on the pipeline and sealing the first cover, and a female sleeve fixedly connected to the female connector and the flange disc at both ends and sleeved between the first cover and the pipeline; the male flange comprises a male connector inserted into the female connector, a male flange disc connected to one side of the female flange disc, and a male sleeve fixedly connected to the male connector and the male flange disc at both ends and sleeved between the female sleeve and the pipeline.

[0010] The low-temperature liquid mass flowmeter further has the following preferred technical solutions: the female sleeve and the cover form a first heat preservation layer, the male sleeve and the pipeline form a second heat preservation layer, and the cover is provided with a vacuum seal.

[0011] The low-temperature liquid mass flowmeter further has the following preferred technical solutions: the stress compensation device is an expansion joint, the expansion joint comprises a connecting ring sleeved between the female sleeve and the female connector, an elastic member arranged between the two connecting rings, and a protective cover sleeved on the connecting ring and fixedly connected to one side connecting ring at one end and gap-fitted to the other side connecting ring at the other end.

[0012] The low-temperature liquid mass flowmeter further has the following preferred technical solutions: the pipeline is divided into an inlet pipe and an outlet pipe, and the shunt body comprises a main body, an interface provided on the main body and divided into an inlet connected to the inlet pipe and an outlet connected to the outlet pipe, and double-row measuring pipes on which a driving coil and a detection coil are mounted, two ends of the double-row measuring pipes being connected to the main body and connected to the inlet pipe and the outlet pipe through the main body to form a passage.

[0013] The low-temperature liquid mass flowmeter further has the following preferred technical solutions: the shunt body further comprises a connecting piece, and the double-row measuring pipes are fixedly connected to the main body through the connecting piece.

[0014] The low-temperature liquid mass flowmeter further has the following preferred technical solutions: the connecting piece is divided into a first connecting piece and a second connecting piece, the double-row measuring pipes are argon arc welded to the first connecting piece, the main body is argon arc welded to the second connecting piece, and the first connecting piece and the second connecting piece are argon arc welded.

[0015] The low-temperature liquid mass flowmeter further has the following preferred technical solutions: the second connecting piece is provided with a groove, and the bottom of the first connecting piece is inserted into the groove to form an arc-shaped shunt cavity.

[0016] Compared with the prior art, the technical scheme of the present application has the following advantages / benefits:

[0017] The present application improves the mass flow meter, sets the heat preservation structure outside the measuring device, prevents the low-temperature liquid from gasification, and then affects the test precision. Meanwhile, the stress compensation device is installed on the measuring device to compensate the stress, prevent the material from shrinking due to cold to generate large stress, and affect the test precision of the flow meter. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0019] Figure 1 is a cross-sectional structure schematic diagram of a low-temperature liquid mass flow meter of the present application.

[0020] Figure 2 is a connection structure schematic diagram of the expansion joint and the flange of the present application.

[0021] Figure 3 is a side view structure schematic diagram of the flow divider of the present application.

[0022] The marks in the figure are: 1 measuring device, 2 heat preservation structure, 3 expansion joint; 11 inlet pipe, 12 flow divider, 13 outlet pipe; 121 main body, 122 interface, 123 double-row measuring pipe, 124 driving coil, 125 detection coil, 126 first connecting piece, 127 second connecting piece, 128 flow dividing cavity, 129 fixing block; 1221 inlet, 1222 outlet; 21 first cover, 22 second cover, 23 male flange, 24 female flange, 26 vacuum sealing element; 231 male joint, 232 male flange plate, 233 male sleeve; 241 female joint, 242 female flange plate, 243 female sleeve; 31 connecting ring, 32 elastic element, 33 shield. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application. Therefore, the detailed description of the embodiments of the present application provided below is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application.

[0024] It should be noted that like reference numerals and letters refer to like items throughout the several views, and once an item is defined in one view, it should not be further defined and explained in subsequent views.

[0025] Embodiment:

[0026] As Figure 1 shown, a low-temperature liquid mass flowmeter comprises a measuring device 1, a heat-insulating structure 2 and a stress compensation device (expansion joint 3). The heat-insulating structure 2 is arranged outside the measuring device 1 to prevent the low-temperature liquid from vaporizing, and the expansion joint 3 serves as the stress compensation device to solve the problem of stress concentration.

[0027] It should be noted that the low-temperature liquid can be liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied natural gas or other low-temperature liquids. The present embodiment is described by taking liquid hydrogen as an example.

[0028] The measuring device 1 comprises a pipeline and a flow divider 12, and the pipeline is connected with the flow divider 12. The pipeline is divided into an inlet pipe 11 and an outlet pipe 13, and the low-temperature liquid enters the flow divider 12 from the inlet pipe 11 and then flows out from the outlet pipe 13. As Figure 3 shown, the flow divider 12 comprises a main body 121, an interface 122 and double-row measuring pipes 123. The interface 122 is arranged on the main body 121, and the interface 122 is divided into an inlet 1221 and an outlet 1222. The inlet pipe 11 is connected with the inlet 1221 through a flange, and the outlet pipe 13 is connected with the outlet 1222 through a flange. The double-row measuring pipes 123 are composed of two female sleeves, and the two ends of the double-row measuring pipes 123 are arranged close to each other on the main body 121 to form a triangular structure, and the two ends of the double-row measuring pipes 123 are communicated with the inlet pipe 11 and the outlet pipe 13, respectively, that is, the low-temperature liquid passes through the inlet pipe 11, the inlet 1221 of the main body 121, the double-row measuring pipes 123 and the outlet 1222 of the main body 121 in sequence. The two parallel test pipes are clamped and positioned by a fixing block 129 at the two ends of the double-row measuring pipes 123, a driving coil 124 is installed on the middle of the double-row measuring pipes 123, and detection coils 125 are arranged at two corners of the "triangle" on the double-row measuring pipes 123. The detection coils 125 need to be installed with magnetic steel and detection coils 125 to measure the phase difference and obtain the mass flow. The measurement of the mass flow is prior art, and thus will not be described in detail.

[0029] In the present application, the coil skeletons of the detection coils 125 and the driving coil 124, and the adhesives and tapes and other materials that need to be used are made of materials suitable for low temperatures. For example, the adhesive is DW-3, and the low-temperature materials involved in the measuring pipe accessories are made of polyimide materials.

[0030] The conventional mass flow meter only insulates the shunt fluid 12, and does not insulate the inlet pipe 11 and the outlet pipe 13, and the temperature of liquid hydrogen is extremely low, and the liquid hydrogen is easily gasified when flowing through the mass flow meter, which seriously affects the test accuracy of the mass flow meter. Therefore, the heat preservation structure 2 comprises a cover and a flange, the cover is sleeved outside the measuring device 1, one end of the flange is arranged at the interface 122, and the other end is used for sealing the cover.

[0031] Specifically, the cover is divided into a first cover 21 and a second cover 22, the first cover 21 is open at both ends, and the second cover 22 is arranged on the outer wall of the first cover 21 and communicates with the first cover 21 in the inside. The first cover 21 is sleeved outside the inlet pipe 11 and the outlet pipe 13, and is used for heat preservation of the inlet pipe 11 and the outlet pipe 13, and the second cover 22 is sleeved on the shunt fluid 12 and is used for heat preservation of the shunt fluid 12.

[0032] More preferably, the flange comprises a male flange 23 and a female flange 24, the male flange 23 is inserted into the female flange 24, the female flange 24 comprises a female connector 241, a female flange plate 242 and a female sleeve 243, the female connector 241 is installed at the interface, one end away from the female connector 241 is provided with the female sleeve 243, the female sleeve 243 is sleeved between the cover and the pipeline, the other end of the female sleeve 243 is fixedly connected with the female flange plate 242, and the female flange plate 242 seals the end opening of the first cover 21. The male flange 23 comprises a male connector 231, a male flange plate 232 and a male sleeve 233, the male flange plate 232 is arranged on the side of the female flange plate 242 away from the cover, the male sleeve 233 is arranged on the male flange plate 232, and the other end of the male sleeve 233 is fixedly connected with the male connector 231. The male connector 231 and the male sleeve 233 form an extended structure, extend into the female sleeve 243, the male connector 231 is inserted into a groove matched with the female connector 241, and communicates with the interface. The pipeline is connected with the male connector 231, and then communicates with the interface.

[0033] Specifically, the pipeline is divided into the inlet pipe 11 and the outlet pipe 13, and the flanges are arranged at the inlet and the outlet of the shunt fluid, the inlet pipe 11 is connected with the inlet through the flange, and the outlet pipe 13 is connected with the outlet through the flange. Taking the inlet of the shunt fluid as an example, one end of the inlet pipe 11 is connected with the male connector 231, and then communicates with the interface. The inlet pipe 11 is sleeved with the male sleeve 233, the female sleeve 243 and the first cover 21 in sequence from outside to inside.

[0034] In the application, the female sleeve 243 and the cover form a first heat preservation layer, the male sleeve 233 and the inlet pipe 11 form a second heat preservation layer, the first heat preservation layer and the second heat preservation layer are vacuum structures, the double vacuum layers are arranged to preserve the pipeline and the measuring device, and the heat preservation effect is good. The cover is further provided with a vacuum sealing element, the distance between the heat preservation layers is related to the diameter of the pipe, in order to meet the heat preservation requirement, the distance between the heat preservation layers needs to be adjusted according to the actual situation, and in the embodiment, the distance between the first heat preservation layers is 40-50 mm.

[0035] In the application, the heat preservation structure is not limited to the vacuum inside, and the heat preservation structure can also be filled with a foaming agent, which is a polyurethane foaming heat preservation material.

[0036] When the temperature changes, the material will expand or shrink, if the expansion and shrinkage degrees of different parts of the structure are different, or the expansion and shrinkage of the structure are limited, thermal stress will be generated, the thermal stress is too large to exceed the allowable stress of the material, the internal stress is too large to affect the test accuracy of the flowmeter, in order to solve the problem, the stress compensation device is arranged in the application to compensate the stress, so as to eliminate the thermal stress.

[0037] The stress compensation device is an expansion joint 3, as shown in the drawings, expansion joints are arranged on the female flanges at both ends of the shunt, the expansion joint 3 is arranged between the female joint and the female sleeve, and the expansion joint 3 comprises a connecting ring 31, an elastic element 32 and a shield 33. Figure 2 The connecting ring has two, one is arranged at the end of the female joint, and the other is arranged at the end of the female sleeve, the elastic element 32 is a spring, which is arranged between the two connecting rings 31 and fixedly connected with the connecting rings 31 at both ends, the cross section of the connecting ring 31 is L-shaped, the shield 33 for supporting is arranged at the top of the connecting ring 31, one end of the shield 33 is fixedly connected with the connecting ring 31 on the female sleeve, and the other end is in gap cooperation with the connecting ring 31 on the female joint.

[0038] After the low-temperature liquid enters, each component is caused to shrink, the elastic element 32 is deformed along the female sleeve in the axial direction, the axial length of the female sleeve is compensated, and the thermal stress is eliminated, and meanwhile, the expansion joint 3 is arranged at the connection between the female sleeve and the female joint, so that stress concentration is prevented.

[0039] In the application, in addition to the expansion joint 3 described in the embodiment, the stress compensation device can also be a bend type expansion joint or a sleeve type expansion joint.

[0040] The existing measuring tube is directly connected with the main body 121 by brazing, and the direct welding of the measuring tube and the main body 121 is prone to cause excessive stress and deformation of the measuring tube, and the brazing material is not resistant to hydrogen embrittlement, and is not suitable for measuring low-temperature liquid hydrogen. In order to solve the above problems, the connecting piece is arranged at the connecting position of the main body 121 and the double-row measuring tube 123, so as to prevent the deformation of the measuring tube caused by the direct welding of the main body 121 and the measuring tube, and the main body 121 and the connecting piece are connected by argon arc welding, and the measuring tube and the connecting piece are connected by argon arc welding, so as to prevent the hydrogen embrittlement phenomenon, and cause the embrittlement and cracking of the shunt.

[0041] More preferably, the connecting piece is divided into a first connecting piece 126 and a second connecting piece 127, both of which are cylindrical, and the second connecting piece 127 is provided with a groove matched with the bottom of the first connecting piece 126, and the bottom of the first connecting piece 126 is recessed and arc-shaped, and the bottom of the first connecting piece 126 is inserted into the groove to form an arc-shaped shunt cavity 128. The double-row measuring tube 123 and the first connecting piece 126 are connected by argon arc welding, the main body 121 and the second connecting piece 127 are connected by argon arc welding, and the first connecting piece 126 and the second connecting piece 127 are connected by argon arc welding.

[0042] In use, the low-temperature liquid enters the main body 121 through the inlet pipe 11, the male joint 231 and the female joint 241 in turn, and then passes through the smooth transition shunt cavity 128 to divide the low-temperature liquid into two paths and enter the double-row measuring tube 123, and the Coriolis force is generated by vibration. The shunt cavity 128 is arranged in an arc-shaped structure, which can make the low-temperature liquid flow more uniformly. After detection, the low-temperature liquid passes through the shunt cavity 128 again and flows into the outlet pipe 13, completes the shunt and confluence, and finally flows out from the outlet pipe 13.

[0043] When the low-temperature liquid is in the inlet pipe 11 or the outlet pipe 13, it is within the heat preservation range of the first heat preservation layer and the second heat preservation layer, which can effectively prevent the low-temperature liquid from being gasified. In addition, the male sleeve and the female sleeve are heat bridge paths, and when the low-temperature liquid flows to the male joint and the female joint, the heat flows along the direction of the male flange plate and the female flange plate through the heat bridge path. Since the heat bridge is the only heat propagation path, the heat exchange between the outside and the inside is greatly reduced, and the heat preservation effect is enhanced.

[0044] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0045] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0046] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature "under", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0047] The above is only the preferred embodiment of the present application, and it should be pointed out that the above preferred embodiment should not be regarded as a limitation on the present application, and the protection scope of the present application should be limited by the scope defined by the claims. For those skilled in the art, without departing from the spirit and scope of the present application, a number of improvements and refinements can also be made, which should also be regarded as the protection scope of the present application.

Claims

1. A cryogenic liquid mass flowmeter characterized by, The utility model relates to a measuring device, a heat preservation structure arranged outside the measuring device and a stress compensation device connected with the measuring device. The measuring device comprises a pipeline and a shunt, and the pipeline is connected with the interface of the shunt. The heat preservation structure comprises a cover shell, which is divided into a first cover shell covering the pipeline and a second cover shell covering the shunt; a flange, one end of which is connected with the interface and the other end of which seals the first cover shell, and the pipeline is sleeved in the flange and connected with the interface through the flange. The flange comprises a male flange and a female flange, and the female flange comprises a female connector connected with the interface, a female flange plate sleeved outside the pipeline and sealing the first cover shell, and a female sleeve fixedly connected with the female connector and the female flange plate at both ends and sleeved between the first cover shell and the pipeline; the male flange comprises a male connector inserted into the female connector, a male flange plate connected with one side of the female flange plate, and a male sleeve fixedly connected with the male connector and the male flange plate at both ends and sleeved between the female sleeve and the pipeline. The stress compensation device is an expansion joint, which comprises a connecting ring sleeved on the female sleeve and the female connector, an elastic member arranged between the two connecting rings, and a shield sleeved on the connecting ring and fixedly connected with one side connecting ring at one end and gap-fitted with the other connecting ring at the other end; the cross section of the connecting ring is L-shaped. A first heat preservation layer is formed between the female sleeve and the cover shell, a second heat preservation layer is formed between the male sleeve and the pipeline, the first heat preservation layer and the second heat preservation layer are vacuum structures, and a vacuum sealing member is arranged on the cover shell.

2. A cryogenic liquid mass flowmeter according to claim 1, wherein, The pipeline is divided into an inlet pipe and an outlet pipe, and the shunt comprises a main body, an interface arranged on the main body and divided into an inlet connected with the inlet pipe and an outlet connected with the outlet pipe, and double-row measuring pipes on which driving coils and detection coils are installed, two ends of the double-row measuring pipes being connected with the main body and connected with the inlet pipe and the outlet pipe through the main body to form a passage.

3. A cryogenic liquid mass flowmeter according to claim 2 wherein, The shunt further comprises a connecting piece, and the double-row measuring pipes are fixedly connected with the main body through the connecting piece.

4. A cryogenic liquid mass flowmeter according to claim 3 wherein, The connecting piece is divided into a first connecting piece and a second connecting piece, the double-row measuring pipes are argon arc welded with the first connecting piece, the main body is argon arc welded with the second connecting piece, and the first connecting piece and the second connecting piece are argon arc welded.

5. A cryogenic liquid mass flowmeter according to claim 4 wherein, The second connecting piece is provided with a groove, and the bottom of the first connecting piece is inserted into the groove to form an arc-shaped shunt cavity.

6. A cryogenic liquid mass flowmeter according to claim 5 wherein, ​

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