CN216348886U

CN216348886U - Flow rate measuring device and mass flow controller

Info

Publication number: CN216348886U
Application number: CN202122403356.8U
Authority: CN
Inventors: 王海亮; 杨玉婧; 苏乾益
Original assignee: Beijing Sevenstar Flow Co Ltd
Current assignee: Beijing Huacheng Electronics Co ltd
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2022-04-19
Anticipated expiration: 2031-09-30

Abstract

The utility model provides a flow measuring device and a mass flow controller, wherein the flow measuring device comprises a measuring pipe, a sealing element, a first mounting seat and a second mounting seat, the measuring pipe comprises a main pipe section and connecting pipe sections positioned at two ends of the main pipe section, and the main pipe section is provided with two windings which are symmetrically arranged; the first mounting seat comprises a main body part and a fixing part, wherein the main body part and the fixing part are of an integral structure and are arranged at an angle; the second mounting seat is arranged on the fixing part and is opposite to the main body part, and an accommodating cavity is formed between the main body part and the second mounting seat; the sealing element is positioned in the accommodating cavity and covers the two windings and at least part of the main pipe section; the connecting pipe section passes through and is connected with the fixing part. By adopting the structure with higher processing precision, assembly precision, fixing reliability and thermal insulation performance, the heat dissipation uniformity can be effectively ensured, so that zero drift is avoided or reduced, and the working reliability is improved.

Description

Flow rate measuring device and mass flow controller

Technical Field

The utility model relates to the technical field of fluid flow measurement, in particular to a flow measurement device and a mass flow controller.

Background

The mass flow controller is used as an instrument for accurately measuring and controlling the flow of fluid (such as gas, liquid and the like), and plays an important role in scientific research and production in the fields of semiconductor microelectronic industry, special material development, chemical industry and the like. The flow measuring device is used as a core component of the mass flow controller, and the working reliability of the flow measuring device directly influences indexes such as measuring precision, linearity and repeatability of the mass flow controller.

The flow measuring device comprises a shell, a measuring pipe arranged inside the shell and a plurality of windings symmetrically arranged on the measuring pipe. Taking two windings as an example, the two windings generate heat after being electrified, and if the heat can be uniformly dissipated outwards through the shell, the working principle of the flow measuring device is as follows: when no fluid exists in the measuring pipe, the heat at the two windings is consistent, and the temperature distribution curve inside the shell is bilaterally symmetrical (bell-shaped curve); when fluid flows through the measuring pipe, the temperature of the pipe wall at the upstream of the measuring pipe is reduced because heat is taken away by the fluid, the temperature of the pipe wall at the downstream is increased because the heat is carried to the downstream from the upstream, the temperature distribution curve in the shell can deviate along with the temperature distribution curve, the temperature change can be sensed by the winding tightly attached to the pipe wall, and corresponding electric signals are output, so that the measurement of the fluid flow is realized.

However, in the prior art, the flow measuring device does not guarantee, for some reason, a uniform outward dissipation of heat, which results in a shift of the temperature profile inside the housing, which is independent of the fluid flowing through the measuring tube, known as "null shift". For example, the casing of the flow measuring device comprises a base and two plate-shaped cover bodies respectively connected to the base, each cover body is provided with a groove, the two cover bodies can be buckled after assembly, the measuring pipe is arranged in the two grooves after buckling, and the end part of the measuring pipe extends into the base and is connected with the base. Wherein, because the cover body and survey buret and connect respectively on the base, the error that produces during the assembly can influence the final cover body and the relative position of surveying buret to the winding that can't guarantee to survey on the buret is located the holistic intermediate position of casing, and then leads to the heat dissipation inhomogeneous easily, takes place "null shift" phenomenon. If the flow measuring device generates 'null shift', the influence on the working reliability is large, and the performance of the flow measuring device cannot meet the requirement.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve at least one technical problem in the prior art and provides a flow measuring device and a mass flow controller.

In a first aspect, the present invention provides a flow measuring device, which includes a measuring tube, a sealing member, a first mounting seat and a second mounting seat, wherein the measuring tube includes a main tube section and connecting tube sections located at two ends of the main tube section, and the main tube section has two windings symmetrically arranged thereon; the first mounting seat comprises a main body part and a fixing part, wherein the main body part and the fixing part are of an integral structure and are arranged at an angle; the second mounting seat is arranged on the fixing part and is opposite to the main body part, and an accommodating cavity is formed between the main body part and the second mounting seat; the sealing element is positioned in the accommodating cavity and covers the two windings and at least part of the main pipe section; the connecting pipe section passes through and is connected with the fixing part.

Furthermore, the main body part is provided with a first groove, the second mounting seat is provided with a second groove, and the first groove and the second groove can jointly enclose an accommodating cavity.

Furthermore, the sealing element comprises two symmetrically-arranged heat insulation blocks, the two heat insulation blocks are respectively placed in the first groove and the second groove, the two windings and at least part of the main pipe section are located between the two heat insulation blocks, and the shape of the accommodating cavity is matched with the shape of the outer contour of the sealing element so as to position the sealing element when the sealing element is assembled.

Furthermore, the fixing part is provided with a first through hole, and the connecting pipe section extends into the first through hole and is connected with the fixing part through the filling body.

Further, first through-hole includes main hole section and necking down section, and the main hole section is located between holding chamber and the necking down section, and the aperture of main hole section is greater than the aperture of necking down section, and the aperture of necking down section and the external diameter looks adaptation of connecting tube section, and the obturator is located the main hole section.

Further, still include the base, first mount pad is connected with the base, and the base is equipped with the second through-hole, and the second through-hole is corresponding with first through-hole, and the connecting pipe section stretches into to the second through-hole after passing first through-hole in, wherein, the terminal surface of connecting the pipeline section and the bottom surface parallel and level of base, and connecting pipe section and second through-hole sealing connection.

Further, still include the shell, the shell cover is established in the outside of first mount pad and second mount pad, and the shell is connected with at least one in first mount pad and the second mount pad.

Furthermore, the top surface of the sealing element protrudes out of the accommodating cavity, and the inner top wall of the shell is pressed on the top surface of the sealing element.

The wire row is arranged on the base, a third groove and a penetrating groove are formed in the bottom surface, facing the base, of the first mounting seat, one side of the penetrating groove is communicated with the accommodating cavity, and the other side of the penetrating groove is communicated with the third groove; one end of the wire row sequentially penetrates through the third groove and the penetrating groove to extend into the accommodating cavity and be electrically connected with the two windings, and the other end of the wire row is used for connecting the outer part.

In a second aspect, the present invention further provides a mass flow controller, which includes a flow measuring device, and the flow measuring device is the above flow measuring device.

The utility model has the following beneficial effects:

the utility model provides a flow measuring device which comprises a measuring pipe, a sealing piece, a first mounting seat and a second mounting seat. The measuring tube comprises a main tube section and connecting tube sections positioned at two ends of the main tube section, and the main tube section is provided with two windings which are symmetrically arranged. The first mounting seat comprises a main body part and a fixing part which are arranged at an angle and are of an integrated structure. The second mounting seat is arranged on the fixing portion and opposite to the main body portion, and an accommodating cavity is formed between the main body portion and the second mounting seat. The sealing element is positioned in the accommodating cavity and covers the two windings and at least part of the main pipe section, and the sealing element mainly covers and seals the two windings and the part of the main pipe section, which is used for arranging the windings, so that a certain sealing and protecting effect is achieved. The connecting pipe section passes through and is connected with the fixing part.

Survey the connecting pipe section of buret and being connected of fixed part, the second mount pad is connected with the fixed part, surveys promptly and all assembles to the body structure that main part and fixed part formed with the second mount pad on to make the structure compacter. Meanwhile, the integrated structure has higher processing precision, so that the accuracy of the position relation among the integrated structure, the measuring tube and the second mounting seat after assembly is favorably ensured; compared with the case that the main body part and the fixing part are of a split structure, the measuring tube and the second mounting seat are assembled by adopting the integrated structure, so that the number of parts for assembly operation can be reduced as much as possible, the assembly error can be reduced, the assembly precision can be improved, the tightness among the parts can be controlled more easily, the positions of a plurality of windings of the measuring tube and the symmetry of the overall structure of the flow measuring device can be ensured after the assembly, and the heat dissipation is more uniform; fixed more fastening and cooperation are more inseparabler between the main part of a body structure and the fixed part, and fixed reliability between them is stronger, can effectively prevent not hard up in order to avoid influencing the heat dissipation homogeneity, and both closely cooperate simultaneously to be favorable to the improvement of thermal insulation performance to guarantee the heat dissipation homogeneity.

Therefore, by adopting the structure with higher processing precision, assembly precision, fixing reliability and thermal insulation performance, the heat dissipation uniformity can be effectively ensured, so that zero drift is avoided or reduced, and the working reliability is improved.

Drawings

FIG. 1 is a schematic front view of a flow measurement device according to an embodiment of the present invention;

FIG. 2 is a schematic side view of the flow measuring device of FIG. 1;

FIG. 3 is a schematic bottom view of the flow measuring device of FIG. 1;

FIG. 4 is a schematic cross-sectional view A-A of the flow measuring device of FIG. 3;

FIG. 5 is a schematic cross-sectional view B-B of the flow measuring device of FIG. 4;

FIG. 6 is a schematic front view of the base, the first mounting seat, and the wire array of the flow measuring device of FIG. 1 after assembly;

FIG. 7 is a schematic cross-sectional view of the flow measuring device of FIG. 6 taken along line C-C;

FIG. 8 is a schematic view of the back side of the wire array of the flow measuring device of FIG. 1;

FIG. 9 is a side view of the wire array of FIG. 8;

FIG. 10 is a schematic illustration of the position of the wire array of the flow measuring device of FIG. 1 after attachment to the windings on the measurement tube;

FIG. 11 is a schematic view of a first mounting block of the flow measurement device of FIG. 1;

FIG. 12 is a bottom view of the first mounting base of FIG. 11;

FIG. 13 is a schematic top view of the first mounting base of FIG. 11;

FIG. 14 is a rear view of the first mounting base of FIG. 11;

FIG. 15 is a schematic cross-sectional view taken along line D-D of the first mount of FIG. 14;

FIG. 16 is a schematic top view of a second mounting block of the flow measuring device of FIG. 1;

FIG. 17 is a front view of the second mounting base of FIG. 16;

FIG. 18 is a schematic cross-sectional view taken along line E-E of the second mount of FIG. 17;

FIG. 19 is a schematic view of the first mounting block, the second mounting block, and the seal of the flow measuring device of FIG. 1 after assembly;

FIG. 20 is a top view of the first and second mounting blocks and seal of FIG. 19;

FIG. 21 is a schematic cross-sectional view of the first mount, the second mount, and the seal of FIG. 20 taken along line F-F;

FIG. 22 is a schematic front view of the base, first mount, second mount, seal, and wire array of the flow measurement device of FIG. 1 after assembly;

FIG. 23 is a schematic top view of the base, the first mounting seat, the second mounting seat, the sealing member, and the wire array of FIG. 22;

fig. 24 is a schematic G-G cross-sectional view of the base, first mount, second mount, seal, and wire row of fig. 22.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the flow measuring device provided by the present invention is described in detail below with reference to the accompanying drawings. In the drawings, the terms "front side", "back side", "top side", "bottom side" and "side" are used only for convenience of description and understanding, and are defined with respect to the orientation of the structures in the drawings, and do not limit the structures of actual products. For example, fig. 1 shows the overall "front" structure of the flow rate measurement device, and the opposite side is the "back" structure, and the side of each component of the flow rate measurement device that is oriented in the same direction as the overall "front" shown in fig. 1 after assembly may also be referred to as the "front" of the component, and the opposite side is the "back" of the component.

The flow measuring device provided by the utility model can be used for measuring the flow of fluid (such as gas, liquid and the like). As shown in fig. 1 to 5, 10 and 22 to 24, in some embodiments, the flow measuring device comprises a measuring tube 10, the measuring tube 10 being used for passing the fluid to be measured. The measuring tube 10 comprises a main tube section 11 and connecting tube sections 12 at both ends of the main tube section 11. The fluid to be measured can enter from the pipe orifice of the connecting pipe section 12 on one side, and flow out from the pipe orifice of the connecting pipe section 12 on the other side after passing through the main pipe section 11. The main tube section 11 has two windings 20 arranged symmetrically thereon. The winding 20 is formed by winding a metal wire on the outer side of the pipe wall of the main pipe section 11 of the measuring pipe 10, and the winding 20 is tightly attached to the pipe wall of the main pipe section 11. The two windings 20 may be energized and generate heat upon energization. Wherein, the metal wire is preferably a thermistor wire.

The flow measuring device measures the flow of the fluid by adopting a capillary heat transfer temperature difference calorimetry principle. When no fluid is present in the measuring tube 10, the heat at the two windings 20 is consistent, and the temperature distribution curve is bilaterally symmetrical (bell curve); when a fluid flows through the main pipe segment 11 of the measuring pipe 10, the temperature of the pipe wall at the upstream of the main pipe segment 11 is reduced due to heat carried away by the fluid, and the temperature of the pipe wall at the downstream is increased due to heat carried from the upstream to the downstream, and the temperature distribution curve is also shifted accordingly. According to the heat conduction characteristic of the metal material, the temperature change of the pipe wall of the main pipe section 11 can be directly reflected to the two windings 20, the balance of an electric bridge built by the two windings 20 is broken, a voltage signal is generated, and the voltage signal can reflect the flow rate of fluid in the main pipe section 11, so that the measurement of the flow rate of the fluid is realized.

As shown in fig. 1-7 and 11-24, in some embodiments, the flow measuring device further includes a first mount 30, a second mount 40, and a seal 50. The first mount 30 includes a main body portion 31 and a fixing portion 32. The main body 31 and the fixing portion 32 are integrally formed and angularly disposed therebetween. The second mounting seat 40 is disposed on the fixing portion 32, the second mounting seat 40 is disposed opposite to the main body portion 31, and an accommodating cavity is formed between the main body portion 31 and the second mounting seat 40. The sealing element 50 is located in the accommodating cavity and covers the two windings 20 and at least part of the main pipe segment 11, and the sealing element 50 mainly covers and seals the two windings 20 and the part of the main pipe segment 11 for arranging the windings 20, so that a certain protection effect is provided for the two windings 20 and the part of the main pipe segment 11. Meanwhile, since the main body 31 and the fixing portion 32 are disposed at an angle, when the second mounting seat 40 is disposed on the fixing portion 32, at least a portion of the fixing portion 32 can correspond to the receiving cavity, so that the connecting pipe section 12 can pass through and be connected to the fixing portion 32. The term "integral structure" means that the main body 31 and the fixing portion 32 are an integral piece, and the two parts are formed by integral processing.

On the one hand, the dimensional tolerance of the integral structure formed by the main body portion 31 and the fixing portion 32 is easier to control and the machining precision is higher than the dimensional tolerance of two separately machined independent pieces. Meanwhile, the main body portion 31 and the fixing portion 32 are integrally formed, so that the problem of assembly error is avoided compared with two independent pieces to be assembled.

In this connection, the second mounting socket 40 is connected to the fastening portion 32 to enable assembly with the above-mentioned monolith, while the measurement tube 10 is also connected to the fastening portion 32 via the connecting tube section 12 to enable assembly with the monolith. That is, the measurement pipe 10 and the second mount 40 are each fitted to the integral piece formed by the body portion 31 and the fixing portion 32, which makes the structure more compact. Meanwhile, the integral piece is higher in machining precision, so that the accuracy of the position relation between the integral piece and the measuring pipe 10 and the position relation between the integral piece and the second mounting seat 40 after assembly can be guaranteed. In addition, the measuring tube 10 and the second mounting seat 40 are assembled by adopting the integral piece, so that the number of parts for assembling operation can be reduced as much as possible, the assembling error can be reduced, the assembling precision can be improved, and the tightness between the parts can be controlled more easily.

In order to avoid "zero drift" or minimize "zero drift" of the flow measuring device, it should be ensured that the two windings 20 of the measuring tube 10 are located at the middle position of the whole structure after assembly is completed, and the whole structure of the flow measuring device should be left-right symmetrical with respect to the center line (as shown in fig. 1 and 4), so that the heat emitted by the two windings 20 can be uniformly radiated outwards, and the influence on the flow measurement of the fluid is reduced. The machining and assembly accuracy of the components of the flow measurement device directly affect the position of the two windings 20 of the assembled measurement tube 10 and the symmetry of the overall structure of the flow measurement device.

For example, in the embodiment shown in the figures, it is only necessary to ensure that the two windings 20 are assembled to the main pipe section 11 of the measuring pipe 10 at symmetrical positions, the measuring pipe 10 and the second mounting block 40 are connected to the fixing portion 32 at predetermined positions, and so on, to enable the assembled flow measuring device to meet the relevant requirements. Therefore, the 'null shift' can be avoided or reduced after the assembling precision is improved by the method.

On the other hand, the main body 31 and the fixing portion 32 are integrally formed, so that the main body 31 and the fixing portion 32 can be fixed more tightly and fit more tightly. The fixing reliability between the main body part 31 and the fixing part 32 is stronger, so that the main body part 31 and the fixing part 32 are prevented from loosening, and the influence on the heat dissipation uniformity caused by the change of the relative positions of the main body part 31 and the fixing part 32 is effectively avoided; meanwhile, the close fit of the main body 31 and the fixing portion 32 is also beneficial to the improvement of the heat preservation performance, thereby ensuring the uniformity of heat dissipation. Therefore, the "null shift" can be avoided or reduced even after the fixing reliability and the heat retaining performance of the main body portion 31 and the fixing portion 32 are improved in the foregoing manner.

By integrating the two aspects, the zero drift is effectively avoided or reduced, the working reliability of the flow measuring device can be improved, and the performance of the flow measuring device is ensured. In addition, the main body portion 31 and the fixing portion 32 are formed as a single integral piece, which is beneficial to reducing the number of parts and improving the assembly and production efficiency.

As shown in fig. 5 and fig. 11 to 24, in some embodiments, the main body portion 31 and the fixing portion 32 are disposed at a right angle, that is, the main body portion 31 and the fixing portion 32 are perpendicular to each other. Of course, in other embodiments not shown in the drawings, the angle between the main body portion 31 and the fixing portion 32 may be an acute angle or an obtuse angle. In particular, in some embodiments, the second mounting seat 40 is connected to a side of the fixing portion 32 facing the accommodating cavity, so that the volume of the second mounting seat 40 assembled with the first mounting seat 30 can be reduced, and the structure is more compact. Specifically, in the embodiment shown in the drawings, the second mount 40 is attached to the fixing portion 32 by a first screw 91. The flow measuring device further includes a base 70, and the first mounting block 30 is attached to the base 70 by a second screw 92. Of course, in other embodiments not shown in the drawings, the second mounting seat 40 may also be connected to a side surface of the fixing portion 32 facing away from the main body portion 31.

In some embodiments, the seal 50 may be made of a solid material that is capable of insulating, for example, the seal 50 may be insulating cotton made of polyimide foam. The two windings 20 and at least part of the main pipe section 11 wrapped by the sealing element 50 can be insulated, so that heat dissipation is reduced, and measurement of fluid flow is facilitated. In addition, even if the structures (such as the first mounting seat 30 and the second mounting seat 40) outside the accommodating cavity are not assembled tightly enough to form a gap, the sealing element 50 can reduce the influence of the gap on the uniformity of heat dissipation.

Further, as shown in fig. 5, 13 to 19 and 24, in some embodiments, the main body 31 is provided with a first groove 311, the second mounting seat 40 is provided with a second groove 41, and when the first mounting seat 30 and the second mounting seat 40 are assembled, the first groove 311 and the second groove 41 together enclose an accommodating cavity. The sealing member 50 can be simultaneously in contact fit with the first recess 311 and the second recess 41, thereby facilitating the placement of the sealing member 50. Preferably, the shape of the receiving cavity formed by the first recess 311 and the second recess 41 may be adapted to the shape of the outer contour of the seal 50 to position the seal 50 when it is assembled. That is, the sealing element 50 fills the entire accommodating cavity, and the outer surface of the sealing element 50 is attached to the cavity walls (i.e., the bottom wall and the side walls in two directions) of the accommodating cavity in three directions. Because the accommodating cavity is formed after the first mounting seat 30 and the second mounting seat 40 are assembled, in the assembling process, the cavity wall of the accommodating cavity can accurately position the sealing element 50, the sealing element 50 is prevented from being dislocated, and the symmetry of the overall structure after assembly is ensured, so that the heat dissipation of the two windings 20 is uniform, and zero drift is avoided or reduced.

Specifically, in some embodiments, the sealing member 50 includes two symmetrically disposed heat-insulating blocks 51, the two heat-insulating blocks 51 can be respectively placed in the first groove 311 and the second groove 41, and the shapes of the first groove 311 and the second groove 41 are matched with the shape of the corresponding heat-insulating block 51, so as to perform a good positioning function on each heat-insulating block 51. For example, in the specific embodiment shown in the figures, the two thermal insulation blocks 51 are long, the cross section of each thermal insulation block 51 is rectangular, and accordingly, the first groove 311 and the second groove 41 are also rectangular grooves, and after the two thermal insulation blocks 51 are respectively arranged in the first groove 311 and the second groove 41, the groove walls of the first groove 311 and the second groove 41 are attached to the corresponding thermal insulation blocks 51 for positioning.

When the first mounting seat 30 is connected to the second mounting seat 40 (for example, after the second mounting seat 40 is connected to the side of the fixing portion 32 facing the accommodating cavity), the two heat insulation blocks 51 are covered by the two windings 20 and at least a part of the main pipe section 11, that is, the two windings 20 and at least a part of the main pipe section 11 are located between the two heat insulation blocks 51, which is more convenient for assembly. In the process, as the first mounting seat 30 and the second mounting seat 40 are fixedly connected, the two insulation blocks 51 clamp the two windings 20 and the main pipe section 11, and can also play a certain fixing role. Of course, it will be understood that in other embodiments, the seal 50 may be pre-wrapped around both the windings 20 and the main tube segment 11, and the seal 50, the windings 20, and the measurement tube 10 may be assembled integrally with the first and second mounting blocks 30, 40.

As shown in fig. 1 to 5, in some embodiments, the flow measuring device further includes a housing 60, the housing 60 is housed outside the first and second mounting

seats

30 and 40, and the housing 60 is directly connected to at least one of the first and second mounting

seats

30 and 40. In the specific embodiment shown in the figures, the housing 60 and the first mounting seat 30 are directly connected and fixed by a third screw 93. The shell 60 can protect the first mounting seat 30, the second mounting seat 40, the measuring pipe 10, the sealing element 50 and other parts inside the shell, and the shell 60 has a good heat preservation effect and is beneficial to ensuring the heat dissipation uniformity. If there is a gap between the first mounting seat 30 and the second mounting seat 40 after the assembly, the housing 60 can also shield the gap, so as to reduce the influence of the gap on the uniformity of heat dissipation. In addition, the relative positions of the housing 60 and the first and second mounting

seats

30 and 40 are fixed and reliable, and the relative movement caused by vibration and other factors can be avoided in the use process of the flow measuring device, so that the structural symmetry of the flow measuring device is ensured.

It should be noted that the housing 60 is not limited to being directly connected to the first and/or second mounting

seats

30 and 40, and in some embodiments, the housing 60 may be directly connected to the base 70. At this time, the case 60 is mounted on the base 70, a closed chamber is formed between the case 60 and the base 70, the first mount 30, the second mount 40, the seal 50, at least a part of the measurement pipe 10, and the winding 20 are placed in the chamber, and the above-described structure in the chamber is bilaterally symmetric with respect to the center line.

As shown in fig. 5, 19 and 24, in some embodiments, the receiving cavity has an opening, a portion of the sealing member 50 extends out of the receiving cavity through the opening, i.e., the top surface of the sealing member 50 protrudes out of the receiving cavity, and the inner top wall of the housing 60 presses against the top surface of the sealing member 50. The seal 50 is compressed by the housing 60 to further ensure that the seal 50 does not become misaligned or loose. It should be noted that the sealing element 50 and the cavity wall of the accommodating cavity may be fixed by gluing or the like; the sealing element 50 and the wall of the accommodating cavity do not need to be additionally connected at the moment, so that the manufacturing process is simplified, and the production efficiency is improved.

Further, as shown in fig. 5, in some embodiments, the housing 60 is attached to at least a portion of an outer surface of an integral structure formed by the first mounting seat 30 and the second mounting seat 40, so that the relative positions of the housing 60 and the first mounting seat 30 and the second mounting seat 40 are fixed and reliable, the package is tight and firm, relative movement due to factors such as vibration is avoided during the use of the flow measuring apparatus, and the fluctuation of the internal ambient airflow is reduced as much as possible, so as to reduce the influence on the uniformity of heat dissipation, and thus reduce "null shift" during the use.

Preferably, in the embodiment shown in the drawings, the bottom surface of the second mounting seat 40 and the top surface (i.e. the surface facing the accommodating cavity) of the fixing portion 32 of the first mounting seat 30 are both flat surfaces, so that the second mounting seat 40 can be tightly attached to the fixing portion 32 after being assembled to the fixing portion. In addition, after the second mounting seat 40 is assembled with the fixing portion 32, the outer surface of the back surface of the second mounting seat 40 is flush with the outer surface of the back surface of the first mounting seat 30 (i.e., the end surface of the fixing portion 32 away from the main body portion 31), and the top surface of the second mounting seat 40 is flush with the top surface of the main body portion 31 of the first mounting seat 30. That is, the first mounting seat 30 and the second mounting seat 40 are assembled to form a cube with regular outer contour. Meanwhile, the housing 60 is also a cube, the inner wall of the housing 60 can be attached to the circumferential outer surface of the integral structure formed by the first mounting seat 30 and the second mounting seat 40, and due to the existence of the part of the sealing element 50 extending out of the accommodating cavity, a certain gap is formed between the housing 60 and the top of the integral structure. The first mounting seat 30, the second mounting seat 40, and the housing 60 have simple structures and low manufacturing costs.

As shown in fig. 4 and 10, in some embodiments, both connecting pipe sections 12 of the measuring pipe 10 are connected to the main pipe section 11 in a bent manner and in the same direction. As shown in fig. 4, 12 and 13, the fixing portion 32 is provided with two first through holes 321, and the connecting pipe section 12 extends into the first through holes 321 and is connected to the fixing portion 32 through the filling body. Wherein, the filling body is formed by a material capable of performing a fixing function, for example, the filling body is formed by a glue used for adhesive connection, and at this time, the connecting pipe section 12 and the first through hole 321 are fixed by adhesion; or formed of solder for welding, in which case the connecting pipe section 12 is welded and fixed to the first through hole 321.

The connecting pipe section 12 of the measuring pipe 10 extends into the first through hole 321 to be connected and fixed in the above manner, so that the assembly difficulty is relatively small, and the connection is firm. Meanwhile, as the processing precision of the hole structure is high, the size of the first through holes 321 is easy to guarantee to be accurate, as long as the sizes of the two first through holes 321 are consistent, the first through holes 321 are filled with materials (such as colloid, soldering tin and the like) for forming the filling body, the usage amount of the materials in the two first through holes 321 is easy to control, and almost the same amount can be guaranteed more accurately, so that the bilateral symmetry of the structure is guaranteed, and zero drift is avoided or reduced.

Further, the first through hole 321 includes a main hole segment 3211 and a necking segment 3212, and the main hole segment 3211 is located between the accommodating cavity and the necking segment 3212. The bore diameter of the main bore section 3211 is larger than the bore diameter of the neck section 3212. The diameter of the neck segment 3212 is adapted to the outer diameter of the connecting tube segment 12 to facilitate passage of the connecting tube segment 12 therethrough. The filler is located within the primary bore segment 3211. When assembling, the measuring tube 10 may first pass through the main hole segment 3211 from top to bottom and extend into the constricted segment 3212, and then fill the main hole segment 3211 with a material such as glue or solder, so that the filling material is retained in the main hole segment 3211 and does not flow out of the constricted segment 3212.

Note that, if the base 70 is connected to the lower portion of the first mounting seat 30, the first through hole 321 may be a hole having a constant diameter, and in this case, the bottom opening of the first through hole 321 may be closed by the base 70, and the filler may be similarly held in the first through hole 321.

As shown in fig. 5, in some embodiments, first mount 30 is coupled to a base 70. The base 70 is provided with a second through hole 71, and the second through hole 71 corresponds to the first through hole 321. The connecting pipe section 12 passes through the first through hole 321 and then extends into the second through hole 71 until the end surface of the connecting pipe section 12 is flush with the bottom surface of the base 70. Since the flow measuring device as a whole needs to be assembled to other structures and the bottom surface of the base 70 needs to be fitted to the structures, aligning the end surface of the connecting pipe section 12 with the bottom surface of the base 70 facilitates subsequent assembly with other structures. Furthermore, the connecting pipe section 12 and the second through hole 71 can be hermetically connected by gluing, welding, or the like.

As shown in fig. 5, 7 to 15, in some embodiments, the bottom surface of the first mounting seat 30 facing the base 70 is provided with a third groove 33 and a through groove 34, and the third groove 33 is communicated with the outside of the first mounting seat 30 from the side surface thereof. Specifically, as shown in fig. 11, the groove bottom of the third groove 33 is parallel to the bottom surface of the base 70, and the side of the third groove 33 corresponding to the front surface of the first mounting seat 30 (i.e., the side of the main body 31 away from the fixing portion 32) is open, so that the third groove 33 can communicate with the outside of the first mounting seat 30 after the first mounting seat 30 is mounted on the base 70. One side of the through groove 34 is communicated with the accommodating cavity, and the other side is communicated with the third groove 33.

In addition, the flow measuring device further includes a wire row 80, and the wire row 80 is flat. As shown in fig. 8 to 10, the wire row 80 includes a first segment, a second segment and a third segment, which are sequentially connected to each other, the first segment and the third segment are substantially parallel to each other, the third segment is provided with a plurality of connection terminals 81, and the plurality of connection terminals 81 are used for electrically connecting with the two windings 20, so as to provide power for the two windings 20 and/or output electrical signals generated by the two windings 20. The side of the second section facing away from the first and third sections is connected to an electronic component 100, and during operation, the electronic component 100 performs a signal processing function.

When assembling, one end of the wire bar 80 sequentially passes through the third groove 33 and the through groove 34 to extend into the accommodating cavity and electrically connect to the two windings 20, and the other end of the wire bar 80 is located outside the first mounting seat 30 and is used for connecting external components (e.g., an external power supply, a control board, etc.). In the embodiment shown in the drawings, the third section of the wire row 80 is inserted into the accommodating cavity through the through slot 34 and electrically connected to the two windings 20 through the connection terminal 81 thereon, the second section of the wire row 80 is disposed in the third groove 33, and the first section of the wire row 80 is located outside the first mounting seat 30.

Further, the width of the line row 80 is matched with the groove width of the third groove 33, and the groove width of the third groove 33 refers to the dimension of the third groove 33 in the direction perpendicular to the routing direction of the line row 80. On the one hand, as long as carry out rational design with the position of third recess 33, just can be through third recess 33 with the accurate location of line row 80 to intermediate position to be convenient for guarantee the symmetry of structure. On the other hand, through being connected of first mount pad 30 and base 70, can make first mount pad 30 compress tightly line row 80 to strengthened the reliability of line row 80 location and installation, the installation is stable, prevents that line row 80 from becoming flexible, avoids line row 80 not flexible back position removal and influence overall structure's symmetry, and then has guaranteed flow measuring device's operational reliability, is favorable to avoiding or reducing "zero drift". Meanwhile, the groove depth of the third groove 33 is preferably 0.1mm to 0.3mm, thereby ensuring that the wire array 80 is not crushed while allowing the wire array 80 to pass therethrough. In addition, the base 70 is further provided with an avoiding groove 72, when the electronic component is assembled, the avoiding groove 72 is located below the third groove 33, and the electronic component 100 is placed in the avoiding groove 72 to prevent the electronic component 100 from interfering with the base 70.

It should be noted that the second mounting seat 40 is connected to the fixing portion 32 of the first mounting seat 30 through the first screw 91, the first mounting seat 30 is connected to the base 70 through the second screw 92, and the housing 60 is connected to the first mounting seat 30 through the third screw 93, wherein the first screw 91, the second screw 92 and the third screw 93 can be effectively connected without being excessively arranged, so that the problem that the screw holes are dislocated and cannot be normally mounted is not easily caused during assembly.

The utility model also provides a mass flow controller, which comprises the flow measuring device. Because above-mentioned flow measuring device's structure can improve "zero drift" phenomenon, flow measuring device's operational reliability is higher, and the performance is better. Therefore, the overall performance index of the mass flow controller comprising the flow measuring device is greatly improved, the measuring precision is higher, the repeatability is better, and the performance is reliable.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the utility model, and these modifications and improvements are also considered to be within the scope of the utility model.

Claims

1. A flow measuring device, comprising a measuring tube, a sealing element, a first mounting seat and a second mounting seat, wherein,

the measuring tube comprises a main tube section and connecting tube sections positioned at two ends of the main tube section, and the main tube section is provided with two windings which are symmetrically arranged;

the first mounting seat comprises a main body part and a fixing part, wherein the main body part and the fixing part are of an integral structure, and an angle is formed between the main body part and the fixing part;

the second mounting seat is arranged on the fixing part and is opposite to the main body part, and an accommodating cavity is formed between the main body part and the second mounting seat;

the sealing element is positioned in the accommodating cavity and covers the two windings and at least part of the main pipe section;

the connecting pipe section penetrates through and is connected with the fixing part.

2. The flow measuring device of claim 1, wherein the main body portion is provided with a first recess and the second mounting seat is provided with a second recess, the first recess and the second recess being capable of cooperatively enclosing the receiving chamber.

3. The flow measuring device of claim 2, wherein the sealing element comprises two symmetrically arranged insulating blocks, the two insulating blocks are respectively placed in the first groove and the second groove, the two windings and at least part of the main pipe section are located between the two insulating blocks, and the shape of the accommodating cavity is adapted to the shape of the outer contour of the sealing element so as to position the sealing element when the sealing element is assembled.

4. The flow measuring device of claim 1, wherein the fixing portion is provided with a first through hole, and the connecting tube section extends into the first through hole and is connected to the fixing portion by a filler.

5. The flow measuring device of claim 4, wherein the first bore includes a main bore section and a constricted section, the main bore section being located between the receiving chamber and the constricted section, the main bore section having a larger bore diameter than the constricted section, the constricted section having a bore diameter that is compatible with an outer diameter of the connecting tube section, and the filler being located within the main bore section.

6. The flow measuring device of claim 4, further comprising a base, wherein the first mounting seat is connected to the base, the base is provided with a second through hole, the second through hole corresponds to the first through hole, the connecting pipe section penetrates through the first through hole and then extends into the second through hole, wherein the end surface of the connecting pipe section is flush with the bottom surface of the base, and the connecting pipe section is hermetically connected to the second through hole.

7. The flow measuring device of any of claims 1-6, further comprising a housing that covers the outside of the first and second mounting seats, the housing being coupled to at least one of the first and second mounting seats.

8. The flow measuring device of claim 7, wherein a top surface of the sealing member protrudes from the receiving chamber, and an inner top wall of the housing presses against the top surface of the sealing member.

9. The flow measuring device of claim 1, further comprising a base and a wire array, wherein,

the first mounting seat is connected to the base, a third groove and a penetrating groove are formed in the bottom surface, facing the base, of the first mounting seat, one side of the penetrating groove is communicated with the accommodating cavity, and the other side of the penetrating groove is communicated with the third groove;

one end of the wire row sequentially penetrates through the third groove and the penetrating groove to extend into the accommodating cavity and be electrically connected with the two windings, and the other end of the wire row is used for being connected with an external part.

10. A mass flow controller comprising a flow measuring device, characterized in that the flow measuring device is a flow measuring device according to any one of claims 1 to 9.