CN204177431U - A kind of mass flow sensor - Google Patents

Abstract

The utility model relates to a mass flow sensor, comprising: a first measuring tube and a second measuring tube, the two measuring tubes have the same structure and are equal in size, and are arranged in parallel in a shell, and the axis of the straight pipe section of each measuring tube is in line with the first oblique The angle between the axis of the pipe section, the angle between the axis of the first inclined pipe section and the axis of the first port section is an obtuse angle, the angle between the axis of the straight pipe section and the axis of the second inclined pipe section, the axis of the second inclined pipe section and the second The included angles of the axes where the port segments are located are all obtuse angles. Through the technical solution of the utility model, when measuring the mass flow rate of compressed natural gas, the resistance to compressed natural gas can be reduced, and the distance can be fixed reliably to ensure that the measuring tube for compressed natural gas flow has a higher mechanical quality factor and a better Stability and strong shock resistance.

Description

A mass flow sensor

technical field

The utility model relates to the technical field of compressed natural gas, in particular to a mass flow sensor for measuring the mass flow of compressed natural gas.

Background technique

The utilization of natural gas as an energy source has the following advantages: first, natural gas is a high-quality green energy, and its combustion emissions are far lower than coal and oil, which can reduce environmental pollution; second, natural gas is a safe energy source, and its components do not Containing carbon monoxide, it can reduce the harm to humans and animals caused by leakage and other problems. At the same time, natural gas has a high ignition temperature and a narrow explosion limit, so it is safe; third, natural gas reserves are abundant and the cost of exploration and development is low. Based on the above advantages, natural gas is playing an increasingly important role in the development of new energy sources. At present, Compressed Natural Gas (CNG) is widely used in electric power, chemical industry, city gas and other fields, especially natural gas-powered vehicles, and the United States, Russia, Japan, New Zealand, Australia, Canada and other countries are vigorously promoting it. With the increasingly widespread application of CNG, the accurate measurement of CNG in the trade process is directly related to the economic interests of both sides of the trade.

The air pressure in the CNG dispenser is generally above 20MPa, and the high pressure will change the sensitive components of the metering tool, thereby affecting its metering characteristics. In addition, due to the low density of CNG, the measurement accuracy requirements for measurement tools are relatively high. The above characteristics of CNG determine that its metering method is different from ordinary fluid metering. At present, the methods that can realize high-pressure gas flow measurement mainly include ultrasonic flowmeter, thermal flowmeter and Coriolis mass flowmeter:

An ultrasonic flowmeter is an instrument that measures flow by detecting the effect of fluid flow on an ultrasonic beam (or ultrasonic pulse). Since the flow channel of the meter is not equipped with any obstructions, it is an unobstructed flowmeter, which can be used for non-contact measurement without pressure loss. However, the ultrasonic measurement method is generally not suitable for flow measurement of pipelines with a diameter below 25mm, and its application range is limited.

Thermal mass flowmeter is an instrument that uses the principle of heat transfer, that is, the heat exchange relationship between the flowing fluid and the heat source (the object heated in the fluid or the heating body outside the measuring tube) to measure the flow rate. It has small pressure loss and simple structure. features. However, its response time is long, and it is not suitable for rapid fluid flow measurement.

The Coriolis Mass Flowmeter (CMF for short) is a resonant sensor that uses the Coriolis effect generated when the fluid flows through its vibrating pipeline to affect the vibration phase or amplitude at both ends of the pipeline to measure the fluid flowing through the pipeline. Mass flow, which can be directly sensitive to fluid mass flow, has the characteristics of high precision, small pressure loss, multi-parameter measurement, etc., and is widely used in the fields of industrial measurement and process control. Compared with the thermal mass flowmeter, its outstanding advantage lies in the large range ratio, which can meet the needs of different occasions. At present, most domestic CNG dispensers use Coriolis mass flowmeters for measurement.

In the CNG filling station, the pressure, temperature, density and flow velocity of the gas are changing rapidly during the filling process, and the gas composition of the natural gas is different at different times and places, so some flowmeters are not suitable for this situation. measuring tool. At present, Coriolis mass flowmeters are widely used as the measurement tool of CNG dispensers at home and abroad. Typical applications are CNG050 produced by Micro Motion of the United States and CNGmass produced by Enders Haus (E+H) of Germany. series, SITRANS FCS200 produced by SIEMENS and so on.

Among them, the common Coriolis mass sensor uses the principle that when the fluid flows in the vibrating tube, a Coriolis force proportional to the mass flow will be generated to measure the mass flow. At present, people generally use the vibrating tube Coriolis mass flow sensor, which is mainly composed of a sensitive unit and a secondary instrument, in which the sensitive unit a includes the measuring tube a1, a2, the exciter a5 and the vibration pickup a3, a4; the secondary instrument b It includes closed-loop control unit b1 and flow calculation unit b2, which are the control and signal processing systems of sensitive units respectively. The sensitive unit outputs the vibration signal related to the measured flow rate; the closed-loop control unit b1 provides the excitation signal to the exciter a5 to keep the measuring tube in a resonant state, and track the vibration frequency of the measuring tubes a1 and a2 in real time; flow calculation The unit b2 processes the output signals of the sensor vibrators a3 and a4 and outputs measurement information, from which the mass flow and density of the measured fluid can be determined.

Due to the U-shaped tube with a large curvature, the above-mentioned sensor will have a large resistance to the flow of compressed natural gas, and there are few fixed distance components, so it is difficult to ensure a high mechanical quality factor, good stability and strong shock resistance .

Utility model content

The technical problem to be solved by the utility model is how to reduce the resistance caused to the compressed natural gas when measuring the mass flow rate of the compressed natural gas, and how to reliably determine the distance, so as to ensure that the measuring tube for the compressed natural gas flow has a high mechanical quality factor, Better stability and strong shock resistance.

For this purpose, the utility model proposes a mass flow sensor for measuring the mass flow of compressed natural gas, comprising: a first measuring tube and a second measuring tube, the structure of the first measuring tube and the second measuring tube The same, equal in size, set in parallel in the shell, wherein each measuring tube includes a straight pipe section, a first arc section, a second arc section, a third arc section, a fourth arc section, a first inclined pipe section, The second inclined pipe section, the first port section and the second port section, wherein the first circular arc section, the first inclined pipe section, the third circular arc section, and the first port section are respectively connected with the second circular arc section and the second inclined pipe section , the fourth arc segment, and the second port segment are symmetrical to a plane that is vertical and equally divides the straight pipe segment, the first arc segment is connected to the straight pipe segment, the first inclined pipe segment is connected to the first arc segment, and the third arc segment is connected to To the first inclined pipe section, the first port section is connected to the third arc section, the second arc section is connected to the straight pipe section, the second inclined pipe section is connected to the second arc section, and the fourth arc section is connected to the second inclined section Pipe section, the second port section is connected to the fourth arc section, the angle between the axis of the straight pipe section and the axis of the first inclined pipe section, the angle between the axis of the first inclined pipe section and the axis of the first port section are obtuse angles, and the straight pipe section The included angle between the axis of the second inclined pipe section and the axis of the second inclined pipe section, and the included angle between the axis of the second inclined pipe section and the axis of the second port section are all obtuse angles; the exciter is arranged on the straight pipe section of the first measuring tube and the second measuring tube The straight pipe section is vertical and equally divided on the plane of the straight pipe section; the first detector is arranged at the connection between the first circular arc section and the first inclined pipe section of the first measuring tube and the second measuring tube; the second detector, It is arranged at the connecting part of the second arc section of the first measuring tube and the second measuring tube and the second inclined pipe section; the first flow divider is arranged outside the housing and connected with the first port section; the second flow divider is arranged at the The outside of the casing is connected to the second port segment; the first nut is arranged outside the casing and connected to the first shunt; the second nut is arranged outside the casing and connected to the second shunt.

Preferably, the exciter includes a coil, a magnetic steel and a fixed bracket, and the coil and the magnetic steel are arranged coaxially, and the fixed bracket is respectively welded to the first measuring tube and the second measuring tube by brazing.

Preferably, the first detector and the second detector respectively include a coil, a magnetic steel and a fixed bracket, and the coil and the magnetic steel are coaxially arranged, and the fixed bracket is respectively welded to the first measuring tube and the second measuring tube by brazing .

Preferably, it also includes: a first distance plate, arranged on the first measuring tube and the connection part of the first port section and the third arc section on the second measuring tube; a second distance plate, arranged on the first measuring tube And the connecting portion of the third arc segment on the second measuring tube and the first inclined tube segment; the third spacer plate is arranged on the first measuring tube and the connection between the second port segment and the fourth arc segment on the second measuring tube part; the fourth spacer plate is arranged on the first measuring tube and the connecting part of the fourth arc segment on the second measuring tube and the second inclined tube segment.

Preferably, it also includes: a first reinforcement sleeve, arranged at the connection between the first port section of the first measuring tube and the first flow divider; a second reinforcement sleeve, arranged at the second port section of the first measuring tube and the second The connection part of the shunt; the third reinforcement sleeve is arranged on the connection part between the first port section of the second measuring tube and the first flow divider; the fourth reinforcement sleeve is arranged on the second port section of the second measuring tube and the second The connection part of the shunt.

Preferably, the first shunt is connected to the first reinforcement sleeve and the third reinforcement sleeve by argon arc welding, and the second shunt is connected to the second reinforcement sleeve and the fourth reinforcement sleeve by argon arc welding , the first reinforcing sleeve and the second reinforcing sleeve are welded to the first measuring tube by brazing, the third reinforcing sleeve and the fourth reinforcing sleeve are welded to the second measuring tube by brazing, and the first A shunt and a second shunt are welded to the housing by argon arc welding.

Preferably, it further includes: a temperature sensor and a fixing piece, the fixing piece is used to fix the temperature sensor to the first distance plate.

Preferably, it also includes: a supporting beam, arranged between the first measuring tube and the second measuring tube, the two ends of which are welded to the first shunt and the second shunt by argon arc welding, and connected to the first measuring tube and the second shunt The second measuring tube is parallel and is used to fix and support the wires inside the housing.

Preferably, it further includes: a connecting pipe and a mating flange, the connecting pipe is used to connect the housing and the mating flange, and the mating flange is sealed with the mating bolt through a rubber post.

Preferably, it further includes: a pressure switch, arranged on the upper surface of the casing, used to detect the pressure inside the casing, and send a prompt message when the pressure is greater than the warning threshold.

Preferably, grooves are provided on the side of the housing.

Through the above technical solution, when measuring the mass flow of compressed natural gas, the resistance to compressed natural gas can be reduced, and the distance can be fixed reliably to ensure that the measuring tube for compressed natural gas has a high mechanical quality factor and good stability and strong shock resistance.

Description of drawings

The features and advantages of the present utility model can be more clearly understood by referring to the accompanying drawings. The accompanying drawings are schematic and should not be construed as any limitation to the present utility model. In the accompanying drawings:

Fig. 1 shows a schematic structural view of a mass flow sensor according to an embodiment of the present invention;

Fig. 2 shows a front view of a mass flow sensor according to an embodiment of the present invention;

Fig. 3 shows a top view of a mass flow sensor according to an embodiment of the present invention;

Fig. 4 shows a schematic structural view of a measuring tube in a mass flow sensor according to an embodiment of the present invention;

Fig. 5 shows a schematic diagram of a detector and an actuator in a mass flow sensor according to an embodiment of the present invention;

Fig. 6 shows a schematic diagram of a distance plate in a mass flow sensor according to an embodiment of the present invention;

Fig. 7 shows a schematic diagram of the installation relationship between the distance plate and the measuring tube in the mass flow sensor according to an embodiment of the present invention;

Fig. 8 shows a schematic diagram of a fixing part in a mass flow sensor according to an embodiment of the present invention;

Fig. 9 shows a schematic diagram of the installation relationship between the fixing piece and the distance plate in the mass flow sensor according to an embodiment of the present invention;

Fig. 10 shows a schematic diagram of the shell side surface of a mass flow sensor according to an embodiment of the present invention.

Explanation of reference numbers:

1-first measuring tube; 2-second measuring tube; 3-exciter; 4-first detector; 5-second detector; 6-first distance plate; 7-second distance plate; 8 - the third distance plate; 9 - the fourth distance plate; 10 - the first nut; 11 - the second nut; 12 - the first diverter; 13 - the second diverter; 14 - the first reinforcement sleeve; 15 - The second reinforcement sleeve; 16-the third reinforcement sleeve; 17-the fourth reinforcement sleeve; 18-support beam; 19-connecting pipe; 20-fitting flange; 24-straight pipe section; 25-first arc section; 26-second arc section; 27-first inclined pipe section; 28-second inclined pipe section; 29-third arc section; 30-fourth arc section ; 31 - the first port section; 32 - the second port section; 34 - the housing.

Detailed ways

In order to more clearly understand the above purpose, features and advantages of the utility model, the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

In the following description, a lot of specific details have been set forth in order to fully understand the utility model, but the utility model can also be implemented in other ways different from those described here, therefore, the protection scope of the utility model is not limited by the following limitations of the specific embodiments disclosed.

As shown in Figures 1 and 2, a mass flow sensor according to an embodiment of the present invention is used to measure the mass flow of compressed natural gas, including: a first measuring tube 1 and a second measuring tube 2, the first measuring tube 1 The structure is the same as that of the second measuring tube 2, the size is equal, and it is arranged in parallel in the housing 34, wherein, as shown in Figure 4, each measuring tube includes a straight pipe section 24, a first arc section 25, a second arc section 26, The third arc section 29, the fourth arc section 30, the first inclined pipe section 27, the second inclined pipe section 28, the first port section 31 and the second port section 32, wherein the first arc section 25, the first inclined pipe section The pipe section 27, the third arc section 29, and the first port section 31 are respectively connected with the second arc section 26, the second inclined pipe section 28, the fourth arc section 30, and the second port section 32 to vertically and equally divide the straight pipe section 24 The plane is symmetrical, the first arc section 25 is connected to the straight pipe section 24, the first inclined pipe section 27 is connected to the first arc section 25, the third arc section 29 is connected to the first inclined pipe section 27, and the first port section 31 is connected to To the third arc section 29, the second arc section 26 is connected to the straight pipe section 24, the second inclined pipe section 28 is connected to the second arc section 30, the fourth arc section 30 is connected to the second inclined pipe section 28, the second The port section 32 is connected to the fourth arc section 30, the angle between the axis of the straight pipe section 24 and the axis of the first inclined pipe section 27, the angle between the axis of the first inclined pipe section 27 and the axis of the first port section 31 are obtuse angles, The angle between the axis of the straight pipe section 24 and the axis of the second inclined pipe section 28, and the angle between the axis of the second inclined pipe section 28 and the axis of the second port section 32 are obtuse angles; as shown in Figure 5, it also includes: exciter 3. Set on the straight pipe section 24 of the first measuring tube 1 and the straight pipe section of the second measuring tube 2 and vertically and equally divide the straight pipe section 24 on the plane; the first detector 4 is arranged on the first measuring tube 1 and the second measuring tube 2 The connecting portion of the first arc segment 25 of the measuring tube 2 and the first inclined tube segment 27; the second detector 5 is arranged between the second arc segment 26 of the first measuring tube 1 and the second measuring tube 2 and the second inclined segment The connection part of the pipe section 28; the first flow divider 12 is arranged outside the casing 34 and is connected to the first port section 31; the second flow divider 13 is arranged outside the casing 34 and is connected to the second port section 32; the first nut 10 , arranged outside the housing 34 , connected to the first shunt 12 ; the second nut 11 , arranged outside the outer casing 34 , connected to the second shunt 13 .

According to the Coriolis effect, the two measuring tubes are fixedly welded on both sides of the measuring tube with double distance plates, and the two measuring tubes are parallel and firmly welded to the outer end surface of the shunt to form a tuning fork to eliminate external vibration Impact. Under the excitation of the electromagnetic exciter, the two measuring tubes vibrate at their natural frequency, and the vibration phase is opposite. Due to the vibration effect of the measuring tube, each fluid microgroup flowing in the tube gets a Coriolis acceleration, and the measuring tube is subjected to a distributed Coriolis force opposite to the acceleration direction. Because the direction of the Coriolis force on the inlet and outlet sides of the measuring tube is opposite, the measuring tube is twisted, and the twisting degree is proportional to the instantaneous mass flow rate in the tube. The two electromagnetic detectors located on the inlet side and the outlet side of the measuring tube detect two vibration signals during each vibration of the tuning fork, and the phase difference of the two signals is proportional to the twist of the detection tube, that is, the instantaneous flow rate. Proportional. By calculating the phase difference between the signals, the mass flow can be calculated.

Since the angle between the axis of the straight pipe section and the inclined pipe section is an obtuse angle, and the angle between the axis of the inclined pipe section and the port section is an obtuse angle, and the two are connected by a circular arc section, the excessive smoothness, when the compressed natural gas flows from the measuring tube, It will not cause large resistance to compressed natural gas, and effectively improve the performance and mechanical quality factor of the resonant sensor, greatly reducing the influence of the flow field, small flow resistance, low pressure loss, and can measure the mass flow of gas, simple processing and low cost Low.

The pipe materials of the two measuring pipes can be 316L stainless steel, titanium, Hastelloy, and of course other materials can also be selected according to the needs. The measuring tube can be integrally formed, or assembled from straight pipe sections, circular arc sections and inclined pipe sections.

When the fluid does not flow through the sensor, the vibrator excites the measuring tube to vibrate at its natural frequency. At this time, the frequency and phase of the sinusoidal signals detected by the two detectors on the inlet side and the outlet side of the measuring tube are exactly the same, and there is no phase difference. Since the measuring tube is empty at this time, the resonant frequency of the measuring tube is the density reference frequency, that is, the frequency when there is no fluid, and the measured real-time density and fluid mass flow values are both 0. When the fluid flows through the sensor, firstly, the flow of the fluid in the measuring tube causes the Coriolis effect to appear, and the two ends of the measuring tube are affected by the distributed Coriolis force of equal magnitude and opposite direction due to the influence of torque, which is manifested as a sinusoidal signal detected by the two detectors There is a phase difference between them, which is proportional to the mass flow rate of the fluid, and the real-time mass flow rate of the fluid can be obtained by detecting the size of the phase difference.

Preferably, the exciter 3 includes a coil, a magnetic steel and a fixed bracket, and the coil and the magnetic steel are arranged coaxially, and the fixed bracket is respectively welded to the first measuring tube 1 and the second measuring tube 2 by brazing. The exciter is used to excite the vibration of the measuring tube. Through the closed-loop control system, the measuring tube is in a state of simple harmonic vibration, and the sensor is vibrated at its natural frequency.

Preferably, the first detector 4 and the second detector 6 respectively include a coil, a magnetic steel and a fixed bracket, and the coil and the magnetic steel are arranged coaxially, and the fixed bracket is respectively welded to the first measuring tube 1 and the second measuring tube 1 by brazing. Tube 2.

Both the exciter and the detector are used in conjunction with a coil and a magnetic steel. The exciter is installed at the central axis of the middle straight pipe section of the two relative measuring pipes, and the detector is located at the smooth transition connection between the first part of the measuring pipe, the arc pipe section and the inclined pipe section. place, and the direction of the detector is installed outward. Together they form a good closed-loop system, which makes the detection tube of the sensor have a stable working state, reduces the influence of external disturbances, and improves the self-regulation ability.

As shown in Figure 7, preferably, it also includes: a first spacer plate 6, which is arranged on the connection part between the first port segment 31 and the third arc segment 29 on the first measuring tube 1 and the second measuring tube 2; Two spacer plates 7 are arranged on the first measuring tube 1 and the connection part of the third arc section 29 on the second measuring tube 2 and the first inclined tube section 27; the third spacer plate 8 is arranged on the first measuring tube 1 And the connection portion between the second port segment 32 and the fourth arc segment 30 on the second measuring tube 2; the fourth spacer plate 9 is arranged on the fourth arc segment 30 on the first measuring tube 1 and the second measuring tube 2 The connecting portion with the second inclined pipe section 28.

As shown in Figure 6, the four spacer plates are composed of two E-type plates, the two spacer plates are located at the smooth connection between the arc section of the measuring tube and the port section, and the two spacer plates are located at the end of the measuring tube The smooth connection between the inclined pipe section and the circular arc section realizes the double distance mode through two sets of spacer plates respectively, so that the resonance frequency of the measuring pipe is high, the stability is good, and the shock resistance is strong. And each spacer plate is also provided with a number of through holes, so that the internal circuit of the shell can pass through, which is beneficial to the layout of the internal circuit.

The distance plate fixes the two measuring tubes at the same time by means of vacuum brazing, so that the measuring tubes are not easily deformed, and the characteristics of the two measuring tubes are as identical as possible, while providing the limited distortion and bending required for flow measurement. The position of the distance plate in the straight pipe section can change the resonant frequency of the sensor, so the position of the double spacer plate in the straight pipe section can be determined according to the designed frequency, so as to reduce the vibration coupling of the internal measuring pipe and enhance the shock resistance of the measuring pipe .

Preferably, it also includes: a first reinforcement sleeve 14 arranged at the connection between the first port section 31 of the first measuring tube 1 and the first flow divider 12; a second reinforcement sleeve 15 arranged at the first measuring tube 1 The connection part of the second port section 32 and the second flow divider 13; the third reinforcement sleeve 16 is arranged on the connection part of the first port section 31 of the second measuring tube 2 and the first flow divider 12; the fourth reinforcement sleeve 17 is provided The connecting portion between the second port section 32 of the second measuring tube 2 and the second shunt 13 .

Preferably, the first shunt 12 is connected to the first reinforcement sleeve 14 and the third reinforcement sleeve 16 by argon arc welding, the second shunt 13 is connected to the second reinforcement sleeve 15 and the fourth reinforcement sleeve 17 by argon arc welding, and the second shunt 13 is connected to the second reinforcement sleeve 15 and the fourth reinforcement sleeve 17 by argon arc welding. A reinforcing sleeve 14, a second reinforcing sleeve 15 are welded to the first measuring tube 1 by brazing, a third reinforcing sleeve 16 and a fourth reinforcing sleeve 17 are welded to the second measuring tube by brazing, 2 the first shunt 12 and the second The two shunts 13 are welded to the casing 34 by argon arc welding.

As shown in FIG. 9 and FIG. 10 , preferably, it further includes: a temperature sensor (not shown in the figure) and a fixing piece 21 , and the fixing piece 21 is used to fix the temperature sensor to the first distance plate 6 .

The temperature sensor fixing part can directly fix the temperature sensor on the distance plate, and can more directly feel the temperature change in the sensor, so as to obtain the sensing value closer to the actual temperature in the detection tube, so as to improve the subsequent processing accuracy.

As shown in Fig. 3, preferably, it also includes: a supporting beam 18, which is arranged between the first measuring tube 1 and the second measuring tube 2, and its two ends are welded to the first shunt 12 and the second shunt by argon arc welding 13, and parallel to the first measuring tube 1 and the second measuring tube 2, for fixing and supporting the wires inside the housing 34. The supporting beams are used to fix and support each wire, which makes wiring more convenient and facilitates regularization and simplification of the internal structure of the housing.

Preferably, it also includes: a connecting pipe 19 and a mating flange 20, the connecting pipe 19 is used to connect the shell 34 and the mating flange 20, and the mating flange 20 is sealed with the mating bolt through a rubber column. The sealing effect and the convenience of installation can be improved by extruding the rubber column and the matching bolt.

Preferably, it further includes: a pressure switch 23, which is arranged on the upper surface of the casing 34, and is used to detect the pressure inside the casing 34, and send a prompt message when the pressure is greater than the warning threshold. By installing a pressure switch on the sensor shell to detect pressure changes inside the sensor shell, a timely warning can be given when the internal pressure is high to prevent damage to the sensor.

As shown in FIG. 10 , preferably, grooves are provided on the side of the casing 34 , which can increase the overall strength of the casing. The shell 34 can specifically be divided into two parts, an upper shell and a lower shell, for easy disassembly and installation.

The technical scheme of the utility model has been described in detail above in conjunction with the accompanying drawings. Considering that in the related art, the U-shaped pipe with a large curvature will generate relatively large resistance to the flow of compressed natural gas, and there are few fixed distance components, it is difficult to ensure a relatively High mechanical quality factor, good stability and strong shock resistance. Through the technical solution of the present application, when measuring the mass flow rate of compressed natural gas, the resistance to compressed natural gas can be reduced, and the distance can be fixed reliably to ensure that the measuring tube for compressed natural gas flow has a higher mechanical quality factor, better stability and strong shock resistance.

In the present invention, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance. The term "plurality" means two or more, unless otherwise clearly defined.

The above descriptions are only preferred embodiments of the utility model, and are not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (10)

1. a mass flow sensor, for measuring the mass rate of compressed natural gas, is characterized in that, comprising:

First measuring tube and the second measuring tube, described first measuring tube is identical with described second measuring tube structure, and size is equal, is set in parallel in shell, and wherein, every root measuring tube comprises straight length, first arc section, second arc section, three-arc section, 4th arc section, first inclined tube section, second inclined tube section, first segment port and the second segment port, wherein, the first arc section, first inclined tube section, three-arc section, first segment port respectively with the second arc section, second inclined tube section, 4th arc section, second segment port is with plane symmetry that is vertical and decile straight length, first arc section is connected to straight length, first inclined tube section is connected to the first arc section, three-arc section is connected to the first inclined tube section, and the first segment port is connected to three-arc section, and the second arc section is connected to straight length, second inclined tube section is connected to the second arc section, 4th arc section is connected to the second inclined tube section, and the second segment port is connected to the 4th arc section, the angle of straight length place axis and the first inclined tube section place axis, the angle of the first inclined tube section place axis and the first segment port place axis is obtuse angle, the angle of straight length place axis and the second inclined tube section place axis, the angle of the second inclined tube section place axis and the second segment port place axis is obtuse angle,

Driver, is arranged at the straight length of the first measuring tube with the straight length of the second measuring tube and in the plane of vertical and decile straight length;

First detecting device, is arranged at the first arc section of the first measuring tube and the second measuring tube and the connecting portion of the first inclined tube section;

Second detecting device, is arranged at the second arc section of the first measuring tube and the second measuring tube and the connecting portion of the second inclined tube section;

First shunt, is arranged at housing exterior, is connected with the first segment port;

Second shunt, is arranged at housing exterior, is connected with the second segment port;

First nut, is arranged at housing exterior, is connected to the first shunt;

Second nut, is arranged at housing exterior, is connected to the second shunt.

2. mass flow sensor according to claim 1, it is characterized in that, described driver comprises coil, magnet steel and fixed support, and coil and magnet steel are coaxially arranged, and fixed support is welded in the first measuring tube and the second measuring tube respectively by soldering.

3. mass flow sensor according to claim 1, it is characterized in that, described first detecting device and the second detecting device comprise coil, magnet steel and fixed support respectively, and coil and magnet steel are coaxially arranged, and fixed support is welded in the first measuring tube and the second measuring tube respectively by soldering.

4. mass flow sensor according to claim 1, is characterized in that, also comprise:

First distance plate, is arranged at the connecting portion of the first segment port and three-arc section on the first measuring tube and the second measuring tube;

Second distance plate, is arranged at the connecting portion of three-arc section and the first inclined tube section on the first measuring tube and the second measuring tube;

3rd distance plate, is arranged at the connecting portion of the second segment port and the 4th arc section on the first measuring tube and the second measuring tube;

4th distance plate, is arranged at the connecting portion of the 4th arc section and the second inclined tube section on the first measuring tube and the second measuring tube.

5. mass flow sensor according to claim 1, is characterized in that, also comprise:

First reinforcing sleeve, is arranged at the first segment port of the first measuring tube and the connecting portion of the first shunt;

Second reinforcing sleeve, is arranged at the second segment port of the first measuring tube and the connecting portion of the second shunt;

3rd reinforcing sleeve, is arranged at the first segment port of the second measuring tube and the connecting portion of the first shunt;

4th reinforcing sleeve, is arranged at the second segment port of the second measuring tube and the connecting portion of the second shunt.

6. mass flow sensor according to claim 5, it is characterized in that, described first shunt is connected with described first reinforcing sleeve and the 3rd reinforcing sleeve by argon arc welding, described second shunt is connected with described second reinforcing sleeve and the 4th reinforcing sleeve by argon arc welding, described first reinforcing sleeve, second reinforcing sleeve is by Welding extremely described first measuring tube, described 3rd reinforcing sleeve and the 4th reinforcing sleeve are by Welding extremely described second measuring tube, described first shunt and the second shunt are soldered to described shell by argon arc welding, the side surface of described shell is provided with groove.

7. mass flow sensor according to claim 4, is characterized in that, also comprise: temperature sensor and fixture, and described fixture is used for described temperature sensor to be fixed on described first distance plate.

8. mass flow sensor according to claim 1, it is characterized in that, also comprise: brace summer, be arranged between the first measuring tube and the second measuring tube, two ends are soldered to the first shunt and the second shunt by argon arc welding, and parallel with the second measuring tube with described first measuring tube, for wire that is fixing and supporting outer inside.

9. mass flow sensor according to any one of claim 1 to 8, is characterized in that, also comprises:

Connecting pipe and adapting flange, described connecting pipe is for connecting described shell and described adapting flange, and described adapting flange is by rubber column and connect bolt seal.

10. mass flow sensor according to any one of claim 1 to 8, is characterized in that, also comprises:

Pressure switch, is arranged at the upper surface of described shell, for detecting the pressure of enclosure, and sends information when pressure is greater than threshold value of warning.