CN114279510A - Anti-electromagnetic interference turbine flowmeter - Google Patents

Abstract

The invention belongs to the field of instruments and meters, and particularly relates to an anti-electromagnetic interference turbine flowmeter. The turbine flowmeter includes: the device comprises a shell, a front flow guider, a rear flow guider, a double-impeller component, a detection probe and a signal converter. Wherein, the shell is of a tubular structure with a fluid channel inside. The middle section of the fluid channel is a turbine cavity; and a probe mounting groove is formed in the outer wall of the shell corresponding to the turbine cavity. The double-impeller assembly is positioned in a turbine cavity of the fluid channel; the dual impeller assembly includes a first impeller, a second impeller, and an impeller shaft. One end of the impeller shaft is rotatably connected to the front fluid director, the other end of the impeller shaft is rotatably connected to the rear fluid director, and the detection probe is positioned in the probe mounting groove; the detection probe comprises a first probe and a second probe, and the detection probe acquires a feedback signal by adopting an electromagnetic induction type probe. The signal converter is used for outputting corresponding flow detection data according to the feedback signal; the invention solves the problem of poor anti-interference capability of the turbine flowmeter on the transformation magnetic field.

Description

Anti-electromagnetic interference turbine flowmeter

Technical Field

The invention belongs to the field of instruments and meters, and particularly relates to an anti-electromagnetic interference turbine flowmeter.

Background

The turbine flowmeter is a speed type flowmeter which comprises a turbine and a probe for detecting the rotating speed of the turbine. When the fluid passes through the turbine flowmeter, the turbine is pushed to rotate at a certain rotating speed; for a particular flow meter, there is a functional relationship between turbine speed and fluid flow therethrough; and the frequency of the pulse signal detected by the probe arranged outside the shell through the electromagnetic sensor is in direct proportion to the rotating speed of the turbine. Therefore, the flow rate of the fluid can be determined by measuring the output frequency of the sensor.

The turbine flowmeter can be used for measuring the flow of fluid such as gas medium, liquid and the like; the flowmeter has the advantages of compact structure, high reliability, relatively low cost, lightning protection, small influence of external factors such as temperature and the like. However, since the turbine flowmeter needs to realize non-contact signal detection by cutting magnetic induction lines depending on the rotation of the turbine blade, the detection accuracy of the flowmeter is easily affected by the electromagnetic interference problem. The poor anti-electromagnetic interference capability is a common fault of the turbine flowmeter, although the influence of an external magnetic field on the measurement precision of the flowmeter can be reduced by arranging a shielding case and the like; however, the interference caused by the transformed magnetic field transmitted from the source of the flowmeter still cannot be effectively solved.

Disclosure of Invention

The invention provides an anti-electromagnetic interference turbine flowmeter, aiming at solving the problem that the anti-interference capability of the turbine flowmeter on a transformation magnetic field is poor.

The invention is realized by adopting the following technical scheme:

a turbine flow meter resistant to electromagnetic interference, the turbine flow meter comprising: the device comprises a shell, a front flow guider, a rear flow guider, a double-impeller component, a detection probe and a signal converter.

Wherein, the shell is of a tubular structure with a fluid channel inside. The fluid channel is in a straight-through type and comprises an inlet end and an outlet end. The middle section of the fluid channel is a turbine cavity; and a probe mounting groove is formed in the outer wall of the shell corresponding to the turbine cavity.

The front deflector is rotatably arranged at one side of the inlet end of the fluid channel in the shell, and the front deflector is coaxially arranged with the fluid channel. The rear fluid director is rotatably arranged at one side of the outlet end of the fluid channel in the shell, and the rear fluid director and the fluid channel are coaxially arranged.

The double-impeller assembly is positioned in a turbine cavity of the fluid channel; the dual impeller assembly includes a first impeller, a second impeller, and an impeller shaft. One end of the impeller shaft is rotatably connected with the front fluid director, the other end of the impeller shaft is rotatably connected with the rear fluid director, and the impeller shaft, the front fluid director and the rear fluid director are coaxially arranged. The first impeller and the second impeller are identical turbines. The first impeller and the second impeller are in the same direction and are sleeved on the impeller shaft at intervals, and the impeller distance between the first impeller and the second impeller is an expert experience value and meets the following requirements: under the condition of the current impeller spacing, the balance coefficient of the fluid elastic disturbance generated between the adjacent impellers and the interference of the generated detectable electric signal is minimum. The installation angles of the first impeller and the second impeller on the impeller shaft have a phase difference, and the phase deviation angle of the blades of the first impeller and the second impeller is larger than the minimum detectable impeller rotation angle and is smaller than or equal to 15 degrees.

The detection probe is positioned in the probe mounting groove; the detection probe comprises a first probe and a second probe. The first probe and the second probe are respectively used for receiving feedback signals generated by the first impeller and the second impeller in the turbine cavity along with the movement of the fluid. The distance and relative position relation between the first probe and the first impeller are completely the same as those between the second probe and the second impeller.

The signal converter is used for acquiring feedback signals received by the first probe and the second probe and outputting corresponding flow detection data according to the feedback signals. The data processing process of the signal converter comprises the following processes: the feedback signal obtained by one probe is used as a detection signal, and the other probe is used as a correction signal. Converting the detection signal and the correction signal into square wave pulses A and B respectively; the timer is started at each signal rising edge of the square wave pulse a and stopped at each nearest signal rising edge of the square wave pulse B, resulting in a time difference Ti. Comparing the time difference Ti with a preset time interval T, and making the following judgment and decision:

(1) when Ti belongs to T, judging that the current signal is a noise signal, and not counting the current pulse signal;

(2) when in use

And judging that the current signal is a non-noise signal, and counting the current pulse signal.

Finally, calculating and outputting a corresponding flow detection result Q according to the current meter coefficient K of the turbine flowmeter and the recorded pulse signal frequency f; wherein Q is K · f.

As a further improvement of the invention, in the double-impeller component, the impeller distance d between the two impellers is in a negative correlation with the outer diameter R of the impeller and is in a positive correlation with the number n of blades of each impeller.

As a further improvement of the invention, the optimal impeller distance d between two impellers for a double-impeller assembly with specific specification_bestThe determination method of (2) is as follows:

(1) fitting a response function eta (d) between a fluid elastic disturbance effect eta generated between the two impellers and an impeller distance d under a preset standard fluid environment;

(2) fitting a response function mu (d) between the interference effect mu of the feedback signals between the two impellers and the impeller distance d under the detection condition of a standard detection probe;

(3) calculating a balance coefficient phi between the fluid disturbance and the signal disturbance according to the following formula:

Φ(d)＝α·η(d)+β·μ(d)

in the above formula, α represents the weight of the influence of the fluid elastic disturbance effect on the detection accuracy of the flowmeter; beta represents the influence weight of the signal interference effect on the detection precision of the flowmeter;

(4) minimum value of calculated balance coefficient phi_minThe corresponding impeller distance d is the optimal impeller distance d in the double-impeller assembly with the current specification_best。

As a further improvement of the present invention, in the double-impeller assembly, the vane phase offset angle θ of the first impeller and the second impeller satisfies:

wherein a represents the minimum detectable impeller rotation angle, in particular the minimum impeller rotation angle detectable by a detection probe in the current turbine flowmeter; min {. is } represents taking a minimum function; n represents the number of blades in each impeller.

As a further improvement of the invention, the probe mounting groove comprises a first groove and a second groove. The first probe is located in the first groove, and the second probe is located in the second groove. The distance between the first groove and the second groove is determined according to the impeller distance between the first impeller and the second impeller in the double-impeller assembly; so as to satisfy: the first probe and the second probe which are arranged in the first groove and the second groove keep constant phase difference of detection signals or the phase difference meets the requirement of error limit under the standard detection state without magnetic field interference.

As a further improvement of the invention, the detection probe is matched with the shape of the probe mounting groove, and the detection probe and the probe mounting groove are assembled by adopting a direct insertion type mounting method. And the detection probe is fixedly connected with the shell through a locking bolt.

As a further improvement of the invention, the shell is made of non-magnetic conductive material; the blades are made of magnetic conductive materials.

As a further improvement of the invention, the detection probe comprises a permanent magnet and a coil, the permanent magnet is used for generating a magnetic field near the corresponding impeller, and the coil is used for receiving a feedback signal generated by cutting magnetic induction lines of the magnetic field during the rotation of the impeller in the double-impeller component.

As a further improvement of the invention, when the outer diameter of the impeller in the turbine flowmeter is 40-50mm and the number of blades of a single impeller is 8, in the double-impeller assembly, the impeller spacing is 5mm, and the phase deviation angle of the blades of the impeller is 15 degrees.

As a further improvement of the invention, an impeller shaft in the double-impeller component is connected with a front flow guider or a rear flow guider through a bearing; sealing flanges for connecting pipelines are arranged in the shell at positions corresponding to the inlet end and the outlet end of the fluid channel.

The technical scheme provided by the invention has the following beneficial effects:

the turbine flowmeter provided by the invention adopts the structural design of double turbines and double probes; the two turbines adopt two coaxial impellers with phase difference, two synchronous detection signals with phase difference can be collected through the signal processing module, interference signals in the signals are eliminated in the signal processing process of different detection signals, and therefore detection accuracy and reliability of the turbine flowmeter in a complex electromagnetic interference environment are improved.

According to the invention, through very complicated mathematical modeling and structural design, the optimal impeller distance and the optimal blade phase deflection angle between two impellers in the double-impeller assembly are determined, and the anti-interference effect of the turbine flowmeter can be expected. The turbine flowmeter has excellent performance, overcomes the inherent defects of the turbine flowmeter, and improves the market application prospect of the turbine flowmeter.

Drawings

Fig. 1 is a schematic structural diagram of an anti-electromagnetic interference turbine flowmeter provided inembodiment 1 of the present invention.

Fig. 2 is a schematic structural diagram of the remaining part of the turbine flowmeter according toembodiment 1 of the present invention, which does not include the detection probe and the signal converter.

Fig. 3 is a schematic structural view of a double impeller assembly inembodiment 1 of the present invention.

Fig. 4 is a schematic disassembly diagram of various parts in the double-impeller assembly provided inembodiment 2 of the present invention.

Fig. 5 is a schematic structural view of a positioning core sleeve inembodiment 2 of the present invention.

Fig. 6 is a schematic structural diagram of a stamping tool of a dual impeller assembly provided inembodiment 3 of the present invention (an extrusion fixture is not shown in the drawing).

Fig. 7 is a schematic view showing the positional distribution of the functional components in a plan view in the press tool according toembodiment 3 of the present invention.

Fig. 8 is a schematic structural view of a core sleeve press-fitting jig inembodiment 3 of the present invention.

Fig. 9 is a schematic structural view of a shaft press-fitting jig inembodiment 3 of the present invention.

Fig. 10 is a schematic structural view of an extrusion jig according toembodiment 3 of the present invention.

Labeled as:

1. a housing; 2. a front deflector; 3. a rear fluid director; 4. a double impeller assembly; 5. detecting a probe; 6. a signal converter; 7. locking the bolt; 11. mounting a probe in a groove; 13. sealing the flange; 41. a first impeller; 42. a second impeller; 43. an impeller shaft; 44. positioning the core sleeve; 51. a first probe; 52. a second probe; 81. a platform; 82. rotating the bracket; 83. stamping an air hammer; 411. a shaft sleeve; 412. a blade; 440. a shaft mounting cavity; 441. a chamfering structure; 821. a support; 822. rotating the base; 831. a hammer body, 832, a punching head; 841. a first positioning seat; 842. a second positioning seat; 843. a first limit guide rod; 851. a shaft limit plate; 852. a wheel limiting seat; 853. a second limiting rod; 861. a fixed seat; 862. a movable seat.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A turbine flow meter resistant to electromagnetic interference, as shown in fig. 1, comprising: the device comprises ashell 1, afront flow guider 2, arear flow guider 3, a double-impeller assembly 4, adetection probe 5 and a signal converter 6.

Wherein, theshell 1 is a tubular structure with a fluid channel inside. The fluid channel is in a straight-through type and comprises an inlet end and an outlet end. The middle section of the fluid channel is a turbine cavity; and aprobe installation groove 11 is arranged on the outer wall of theshell 1 corresponding to the position of the turbine cavity.

As shown in fig. 2, thefront deflector 2 is rotatably installed at one side of the inlet end of the fluid passage in thehousing 1, and thefront deflector 2 is coaxially disposed with the fluid passage. Therear fluid director 3 is rotatably installed at one side of the outlet end of the fluid passage in thehousing 1, and the rear fluid director is coaxially arranged with the fluid passage.

Thetwin impeller assembly 4 is located within the turbine chamber of the fluid passageway. As shown in fig. 3, thedual impeller assembly 4 includes afirst impeller 41, asecond impeller 42, and animpeller shaft 43. One end of theimpeller shaft 43 is rotatably connected to thefront fluid director 2, and the other end is rotatably connected to therear fluid director 3, and the three are coaxially arranged. Specifically, theimpeller shaft 43 in the double-impeller assembly 4 is connected with thefront deflector 2 or therear deflector 3 through a bearing. Thefirst impeller 41 and thesecond impeller 42 are identical turbines. Thefirst impeller 41 and thesecond impeller 42 are arranged on theimpeller shaft 43 in the same direction and in a sleeved mode at intervals, the impeller distance between thefirst impeller 41 and the second impeller is an expert experience value, and the following conditions are met: under the condition of the current impeller spacing, the balance coefficient of the fluid elastic disturbance generated between the adjacent impellers and the interference of the generated detectable electric signal is minimum. Thefirst impeller 41 and thesecond impeller 42 are installed on theimpeller shaft 43 with a phase difference in which theblades 412 are out of phase by 15 ° or more from the minimum detectable impeller rotational angle.

Thedetection probe 5 is positioned in theprobe mounting groove 11; theinspection probe 5 includes afirst probe 51 and asecond probe 52. Thefirst probe 51 and thesecond probe 52 are used for receiving feedback signals generated by thefirst impeller 41 and thesecond impeller 42 in the turbine cavity along with the movement of the fluid respectively. The distance and relative positional relationship between thefirst probe 51 and thefirst impeller 41 are completely the same as those between thesecond probe 52 and thesecond impeller 42. Thedetection probe 5 comprises a permanent magnet and a coil, the permanent magnet is used for generating a magnetic field near the corresponding impeller, and the coil is used for receiving a feedback signal generated by cutting magnetic induction lines of the magnetic field in the rotation process of the impeller in the double-impeller assembly 4.

The signal converter 6 is configured to obtain feedback signals received by thefirst probe 51 and thesecond probe 52, and output corresponding flow detection data according to the feedback signals. The data processing process of the signal converter 6 includes the following processes: the feedback signal obtained by one probe is used as a detection signal, and the other probe is used as a correction signal. Converting the detection signal and the correction signal into square wave pulses A and B respectively; the timer is started at each signal rising edge of the square wave pulse a and stopped at each nearest signal rising edge of the square wave pulse B, resulting in a time difference Ti. Comparing the time difference Ti with a preset time interval T, and making the following judgment and decision:

(1) when Ti belongs to T, judging that the current signal is a noise signal, and not counting the current pulse signal;

(2) when in use

And judging that the current signal is a non-noise signal, and counting the current pulse signal.

Finally, calculating and outputting a corresponding flow detection result Q according to the current meter coefficient K of the turbine flowmeter and the recorded pulse signal frequency f; wherein Q is K · f.

The present embodiment provides a turbine flowmeter that uses adual impeller assembly 4 having two impellers with a specific phase difference, and aseparate sensing probe 5 is provided for each impeller. The double-impeller assembly 4 is coaxially arranged in the use process, so that the two impellers can keep rotating in the same direction and at the same speed in the detection process. However, since the two impellers have a certain phase offset angle of theblades 412, the feedback signals of the cutting lines generated by the two impellers have a specific phase difference.

In this scenario, the present embodiment compares the two feedback signals acquired by thedetection probe 5 with each other, and corrects them. When the flowmeter operates in a high electromagnetic interference environment, the two probes can obtain two paths of detection signals. According to the relation between the actual phase difference and the theoretical phase difference in the two paths of signals, the detection signals are subjected to specific signal processing, interference signals can be distinguished and eliminated, and only useful real signals are reserved. Thereby achieving the effects of anti-electromagnetic interference and automatic calibration; the detection accuracy and reliability of the turbine flowmeter in a complex electromagnetic environment are improved.

One technical key point of the scheme provided by the embodiment is the setting of the impeller distance between the two impellers. When the impeller distance between two impellers in the double-impeller assembly 4 is set to be too wide, obvious fluid disturbance can be caused between the two impellers, so that the final flow detection result is influenced, and the double-impeller assembly 4 can be seriously or even damaged. The solution of this embodiment is theoretically intended to set the distance between the two impellers small enough so that thedouble impeller assembly 4 can be nearly equivalent to a single impeller. However, in the practical application process, the distance between the impellers cannot be too small, so that the detection signals on the impellers need to be measured independently, and then two independent detection signals are generated for signal processing, so that the anti-interference effect is realized. When the distance between the impellers is too small, when the two probes detect the feedback signals on the respective corresponding impellers, interference occurs between the magnetic fields generated by the two probes, and the feedback signals acquired by thedetection probe 5 are misaligned.

In addition, in the turbine flowmeter provided in the present embodiment, the impeller distance between the two impellers in thedual impeller assembly 4 is actually related to the number of theouter diameter blades 412 of the impellers, and these two parameters affect the fluid elastic disturbance effect generated in the fluid by the two impellers. Specifically, for thedual impeller assembly 4 in an ideal condition, the impeller spacing d is inversely related to the impeller outer diameter R and is positively related to the number n ofblades 412 of each impeller.

In order to determine the optimal impeller spacing of thedual impeller assembly 4 in the turbine flowmeter, the present implementation also proposes a new digitization processing method. In this method, the optimum impeller spacing d between the two impellers is specified for a particular specification of thetwin impeller assembly 4_bestThe determination method comprises the following steps:

(1) fitting a response function eta (d) between a fluid elastic disturbance effect eta generated between the two impellers and an impeller distance d under a preset standard fluid environment;

(2) fitting a response function mu (d) between the interference effect mu of the feedback signals between the two impellers and the impeller distance d under the detection condition of thestandard detection probe 5;

(3) calculating a balance coefficient phi between the fluid disturbance and the signal disturbance according to the following formula:

Φ(d)＝α·η(d)+β·μ(d)

in the above formula, α represents the weight of the influence of the fluid elastic disturbance effect on the detection accuracy of the flowmeter; beta represents the influence weight of the signal interference effect on the detection precision of the flowmeter;

(4) minimum value of calculated balance coefficient phi_minThe corresponding impeller distance d is the optimal impeller distance d in the double-impeller assembly 4 with the current specification_best。

After acquiring enough test data, the above method for determining the optimal impeller spacing can be obtained in a computer through corresponding software simulation. And produces the optimum impeller spacing for atwin impeller assembly 4 of any specification.

In the present embodiment, another factor affecting the detection accuracy of the turbine flowmeter is the phase deviation angle of theblade 412 between the two impellers in thedual impeller assembly 4. It is contemplated that too little phase skew of thevanes 412 will not allow the phase difference of the feedback signal between the twovanes 412 to be easily measured, and that too little phase skew of thevanes 412 will cause significant fluid drag between the twovanes 412. Therefore, the present embodiment makes the phase deviation angle θ of theblades 412 of thefirst impeller 41 and thesecond impeller 42 limited as follows:

wherein a represents the minimum detectable impeller rotation angle, in particular the minimum impeller rotation angle detectable by thedetection probe 5 in the current turbine flowmeter; min {. is } represents taking a minimum function; n represents the number ofblades 412 in each impeller. Under the state of the phase deflection angle of theblade 412, the reliability of the detection result in a complex electromagnetic environment can be ensured, and the detection precision of the turbine flowmeter can be obviously improved.

In the present embodiment, the outer diameter of the impeller in the rotational flowmeter is 40-50mm, and the number of theblades 412 of a single impeller is 8, so the impeller pitch in thedual impeller assembly 4 is set to 5mm, and the phase deviation angle of theblades 412 of the impeller is 15 °.

As shown in fig. 2, theprobe installation groove 11 of the present embodiment includes a first groove and a second groove. Afirst probe 51 is located in the first slot and asecond probe 52 is located in the second slot. The distance between the first groove and the second groove is determined according to the impeller distance between thefirst impeller 41 and thesecond impeller 42 in the double-impeller assembly 4; so as to satisfy: thefirst probe 51 and thesecond probe 52 which are arranged in the first groove and the second groove keep constant phase difference of detection signals or the phase difference meets the requirement of error limit under the standard detection state without magnetic field interference.

In order to facilitate the installation of thedetection probe 5, the state problem of thedetection probe 5 can be guaranteed in the using process, and the detection error caused by the shaking or the offset of thedetection probe 5 is eliminated. In the embodiment, thedetection probe 5 is assembled in theprobe installation groove 11 by adopting a direct insertion type installation method, so that the structural connection between thedetection probe 5 and theprobe installation groove 11 is ensured to be firm. In addition, the stability and the anti-vibration effect of the turbine flowmeter are further improved. The embodiment also fixedly connects thedetection probe 5 with theshell 1 through alocking bolt 7.

Thehousing 1 of the turbine flowmeter in the present embodiment should be made of a non-magnetic conductive material, specifically 304 stainless steel in the present embodiment, and in addition, other materials, such as a resin material, may be selected according to the corrosion resistance, structural strength, aging resistance, and cost of the specific application scenario, under the constraint of satisfying the non-magnetic conductivity. Theblades 412 of the turbine flowmeter in this embodiment are made of a magnetically conductive material. Specifically, the present embodiment employs 440C stainless steel for theblades 412 in the dual turbine assembly.

In addition, in order to facilitate the installation and use of the turbine flowmeter, the present embodiment is provided with sealingflanges 13 for connecting pipes in thehousing 1 at positions corresponding to the inlet and outlet ends of the fluid passage. In order to be convenient to adapt to different application scenes, the sealingflange 13 at the end part of the turbine flowmeter provided by the embodiment is assembled with theshell 1 in an exchangeable connection mode. Thereby being convenient for being matched with sealingflanges 13 with different specifications for use.

Example 2

The present embodiment provides adual impeller assembly 4 for a tamper-resistant flowmeter, and thedual impeller assembly 4 is a key component in the turbine flowmeter inembodiment 1. The assembly requires very high structural dimensions and machining accuracy. Therefore, if the conventional precision machine tool is used for production, the difficulty of the machining process and the final machining cost are difficult to control. The present embodiment designs the requireddouble impeller assembly 4 as a split-assembly product and as four different parts according to different structural features. And further the difficulty of the processing technology and the production cost can be greatly reduced.

Specifically, thedual impeller assembly 4 includes two identical impellers coaxially disposed with aspecific blade 412 phase angle and a specific impeller spacing on theimpeller shaft 43. Thedual impeller assembly 4 is assembled by an assembly process. As shown in fig. 4, the parts of thetwin impeller assembly 4 include: afirst impeller 41, asecond impeller 42, apositioning core sleeve 44 and animpeller shaft 43. Of the above four parts, thefirst impeller 41 and thesecond impeller 42 are conventional impeller products, and can be used in common with existing products. Theimpeller shaft 43 is also available in connection with existing products and is relatively difficult to machine if custom machining is required. The only part that requires special machining is the locatingcore sleeve 44. Although thepositioning core sleeve 44 in this embodiment is a special component designed for the product of this embodiment, the difficulty of processing the component itself is low. And thus the production cost can be effectively controlled. The core technical feature of thepositioning core sleeve 44 is the limitation of special specification and size for the characteristic tea grower. The requirement of 44-degree machining precision of the positioning core sleeve is high.

Aiming at the four parts, the assembly of the double-impeller component 4 can be completed by adopting a simple stamping process, so that the process difficulty is greatly reduced and the production cost is effectively controlled compared with the integrated product processing process. Aiming at the requirement of the processing technology, theimpeller shaft 43 in the embodiment is in interference fit with theshaft mounting cavity 440 of thepositioning core sleeve 44; the second section of thepositioning core sleeve 44 is in interference fit with the inner hole of thesecond shaft sleeve 411; the first section of thepositioning core sleeve 44 is in interference fit with the inner hole of thefirst shaft sleeve 411.

Thefirst impeller 41 includes afirst shaft sleeve 411 andblades 412 arranged on thefirst shaft sleeve 411 in a rotating array. Thesecond impeller 42 includes asecond hub 411 andblades 412. Thesecond impeller 42 and thefirst impeller 41 have the same specifications except for the inner diameter of theshaft sleeve 411, and the inner diameter of thesecond shaft sleeve 411 is larger than that of thefirst shaft sleeve 411.

As shown in FIG. 5, thepositioning core sleeve 44 contains a cylindricalshaft mounting cavity 440; the outer circumference of thepositioning core sleeve 44 is divided into three sections along one end to the other end in a step-type reducing mode; wherein the outer circumference of the first section matches the inner diameter of saidfirst hub 411. The outer circumference of the second section matches the inner diameter of thesecond bushing 411. The outer circumference of the third section is larger than the inner diameter of thesecond hub 411. The length of the first segment of thepositioning core sleeve 44 is greater than the thickness of thefirst sleeve 411. The length of the second segment of thepositioning core housing 44 is equal to the sum of the thickness of thesecond shaft housing 411 and the preset impeller spacing.

Theimpeller shaft 43 is an optical axis, and the outer diameter of theimpeller shaft 43 is equal to the inner diameter of theshaft mounting cavity 440 of thepositioning core sleeve 44. The upper and lower ends of theimpeller shaft 43 are also chamfered for ease of installation.

Further, in the present embodiment, the first section of thepositioning core housing 44 includes a straight cylindrical portion and achamfered structure 441 portion with a tapered outer diameter at the front end of the straight cylindrical portion; the length of the straight cylindrical portion is equal to the width of thefirst sleeve 411; the total volume of the chamferedstructure 441 portion is equal to the volume of the third segment of thepositioning core sleeve 44.

In this embodiment, thechamfer structure 441 of thepositioning core sleeve 44 has two functions: first, the structural assembly is facilitated, and thepositioning core housing 44 having the chamfer is easily inserted into theboss 411 of each impeller. And plays a guiding role; the probability of part deformation and product scrapping caused by junction deviation in the machining process is reduced. Secondly, a structure identical to the third section of thepositioning core sleeve 44 can be obtained through the deformation of thechamfering structure 441, so that the structural consistency of the two ends of thefirst impeller 41 and thesecond impeller 42 is maintained in the finished product, and a better flow detection effect is generated.

It should be noted that: the present embodiment produces the same nut-like structure by deforming chamferedstructure 441 under pressure; this result is also beneficial for improving the structural stability and strength of the assembled assembly. Of course, in other embodiments, the turning after assembly may ensure that the structures on both sides of thefirst impeller 41 and thesecond impeller 42 are consistent.

In this embodiment, thefirst impeller 41, thesecond impeller 42, thepositioning core housing 44 and theimpeller shaft 43 are made of 440C stainless steel material subjected to heat treatment of hardness and strength. The material can meet the requirement of magnetic conductivity, and has good weather resistance, corrosion resistance and structural strength. In the present embodiment, in order to reduce the structural deformation of the twin-impeller assembly 4 during the machining process, the material is also subjected to heat treatment processing of hardness and strength.

The double-impeller component 4 provided in this embodiment is assembled by the following assembly method:

(1) coaxially placing thepositioning core sleeve 44, thesecond impeller 42 and thefirst impeller 41 in sequence from top to bottom, and executing a first stamping action; so that thefirst impeller 41 snaps into thealignment core housing 44 at the intersection of the first and second segments and thesecond impeller 42 snaps into thealignment core housing 44 at the intersection of the second and third segments.

(2) Inserting theimpeller shaft 43 into the assembly in the previous step at a position corresponding to theshaft mounting cavity 440 in thepositioning core sleeve 44, and performing a second stamping action; so that theimpeller shaft 43 penetrates theshaft mounting cavity 440 in thepositioning core sleeve 44 and the portions of theimpeller shaft 43 protruding at both ends of thepositioning core sleeve 44 are of equal length.

(3) The assembly in the above step is placed in a jig, and the upper end and the lower end of the jig are provided with through holes matched with theimpeller shaft 43; theimpeller shaft 43 extends from the through hole, and the part of the jig corresponding to thechamfer structure 441 in thepositioning core sleeve 44 comprises an extrusion groove which is the same as the third section structure in thepositioning core sleeve 44.

(4) A third stamping action is performed on the jig of the previous step, so that the chamferedstructure 441 is deformed into the same structure as the third section of thepositioning core sleeve 44.

According to the description of the assembly process, the assembly process of the product provided by the embodiment is relatively simple, the assembly processing efficiency is good, personnel training is easy to carry out, and the assembly process is suitable for large-scale industrial automatic processing, so that the production cost of the product can be effectively reduced, and obvious economic benefits are generated.

In order to improve the yield of assembly and processing and reduce the overall production cost in the embodiment, thechamfer structure 441 of thepositioning core sleeve 44 is locally annealed before processing, so that the hardness of thechamfer structure 441 part is reduced. And then after the assembly is finished, carrying out integral heat treatment and/or surface treatment according to the requirements of physical and chemical properties, and further obtaining the required final product of the double-impeller assembly 4. For example, the product can be subjected to finish machining to remove burrs, and the deformation rates of different structures are detected; quenching treatment is carried out, or other processing such as electroplating and polishing is carried out on the product, so that the comprehensive performance of the double-impeller assembly 4 is improved.

Example 3

In order to effectively improve the assembly efficiency of the twin-impeller unit 4 inembodiment 2, reduce assembly damage, and improve assembly accuracy and yield. The embodiment further provides a punching tool special for the double-impeller assembly 4.

The punching tool can adopt the parts in theembodiment 2, and the double-impeller component 4 meeting the requirements is processed through three times of punching actions. As shown in fig. 6 and 7, the press tool includes:platform 81, runingrest 82, punchingpress air hammer 83, core cover pressure equipment tool, axle pressure equipment tool and extrusion tool.

The rotatingbracket 82 includes abracket 821 and arotating base 822. Thesupport 821 comprises a vertical rod and a horizontal rod which are perpendicular to each other, and the vertical rod is fixedly arranged in the center of theplatform 81 through arotating base 822; therotary base 822 is used for driving thesupport 821 to rotate and respectively stay at three different punching stations.

Ram air hammer 83 includes aram body 831 and aram head 832. Theram air hammer 83 is arranged below the cross rod; the punchinghead 832 of the punchingair hammer 83 is shaped like a cake, and the pressing direction is downward. Thepunch 832 is centrally provided with a first axial bore having an inner diameter matching the outer diameter of theimpeller shaft 43.

As shown in fig. 8, the core housing press-fitting jig is located outside thebracket 821 and just below the first punching station of the punchingair hammer 83. The core sleeve press-fitting jig comprises afirst positioning seat 841, asecond positioning seat 842 and a first limitingguide rod 843. Thefirst positioning seat 841 is fixedly installed on the surface of theplatform 81. A first wheel groove for accommodating thefirst impeller 41 is arranged on the upper surface of thefirst positioning seat 841; the bottom of the first wheel groove is provided with a limit groove matched with the bottom profile of thefirst impeller 41. A plurality of first limitingguide rods 843 which extend vertically and upwards are arranged around thefirst positioning seat 841. Thesecond positioning seat 842 has the same structure as thefirst positioning seat 841; thesecond positioning seat 842 is a split structure split along the longitudinal direction, and includes a left half seat and a right half seat. Limiting guide holes which are the same as the first limitingguide rod 843 in position and matched with the apertures are formed in the peripheries of the left half seat and the right half seat; thesecond positioning seat 842 is sleeved on the first limitingguide rod 843. Thesecond positioning seat 842 is provided with a second wheel groove for accommodating thesecond impeller 42, and the bottom surface of the second wheel groove is also provided with a limit groove; and the limiting grooves in thefirst positioning seat 841 and thesecond positioning seat 842 deflect relatively, and the deflection angle is equal to the phase deflection angle of thepreset blade 412. The thickness of the bottom of the second wheel groove in thesecond positioning seat 842 is equal to the preset impeller distance; the centers of the bottoms of thefirst positioning seat 841 and thesecond positioning seat 842 are provided with through holes with inner diameters not smaller than the outer diameter of the second section of thepositioning core sleeve 44.

As shown in fig. 9, the shaft press-fitting jig is located outside thebracket 821 and just below the second press station of thepress air hammer 83. The shaft press-fitting jig comprises ashaft limiting plate 851 and awheel limiting seat 852; a plurality of second limitingguide rods 853 extending vertically upwards are arranged on the periphery of thewheel limiting seat 852, and limiting guide holes with the same positions as the second limitingguide rods 853 and matched apertures are arranged on the periphery of theshaft limiting plate 851; theshaft limit plate 851 is sleeved on the secondlimit guide rod 853. Theshaft stopper plate 851 has a shaft through hole formed therein to match the outer diameter of theimpeller shaft 43. Thewheel limiting seat 852 is internally provided with an impeller groove matched with the combined profile of thefirst impeller 41, thesecond impeller 42 and thepositioning core sleeve 44; the depth of the impeller groove is flush with the height of the assembly. The center of the bottom of the impeller groove is provided with a second shaft hole, the inner diameter of the second shaft hole is matched with the outer diameter of theimpeller shaft 43, and the depth of the second shaft hole is equal to the length of the part of theimpeller shaft 43 extending to the two sides of the impeller in the double-impeller assembly 4.

As shown in fig. 10, the pressing jig is located outside thebracket 821 and just below the third press station of thepress air hammer 83. The extrusion jig comprises a fixedseat 851 and amovable seat 852. Thebase 851 is mounted on theplatform 81 at the bottom; the upper portion of the fixingbase 851 includes a first limiting groove, and the bottom of the first limiting groove is provided with an extrusion groove, and the extrusion groove is matched with the outer contour of the third section of thepositioning core sleeve 44. The extrusion grooves are used for extruding the chamferedstructure 441 at the bottom of thepositioning core sleeve 44 into the same structure as the third section of thepositioning core sleeve 44. A second shaft hole is further formed in the fixingseat 851 below the extrusion groove, the inner diameter of the second shaft hole is matched with the outer diameter of theimpeller shaft 43, and the depth of the second shaft hole is equal to the length of the part of theimpeller shaft 43, extending out of the two sides of the impeller, in the double-impeller assembly 4. Themovable seat 852 is structurally symmetrical with the fixedseat 851 and is located above the fixedseat 851; themovable seat 852 is provided with a second limiting groove, and the total groove depth when the first limiting groove and the second limiting groove are combined is equal to the height of the combination of thefirst impeller 41, thesecond impeller 42 and thepositioning core sleeve 44.

The working process of the stamping tool is as follows:

firstly, an operator or a manipulator places thefirst impeller 41 in thefirst positioning seat 841, and thefirst impeller 41 is engaged with the contour of the limiting groove in thefirst positioning seat 841; then, the splitsecond positioning seat 842 is completely assembled and then inserted downwards along the first limitingguide rod 843, so that thesecond positioning seat 842 is close to thefirst positioning seat 841; then, thesecond impeller 42 is placed in thesecond positioning seat 842, and thesecond impeller 42 is engaged with the limiting groove in thesecond positioning seat 842. Finally, thepositioning core sleeve 44 is inserted into the inner hole of theshaft sleeve 411 of thesecond impeller 42. And then, the initialization of the core sleeve press-fitting jig is completed.

Next, therotary frame 82 rotates theram air hammer 83 to the first press station, and thepress head 832 presses downward to perform the first press operation. Thepositioning core housing 44 is pressed into thefirst impeller 41 and thesecond impeller 42, and thefirst impeller 41 is snapped into thepositioning core housing 44 at the intersection of the first segment and the second segment, and thesecond impeller 42 is snapped into thepositioning core housing 44 at the intersection of the second segment and the third segment.

After the first punching operation is completed, the punchinghead 832 is lifted, and an operator or a robot takes the combined body of thesecond positioning seat 842 off from the upper side of the secondspacing guide rod 853, detaches the left half seat and the right half seat in thefirst positioning seat 841, and takes the first combined body of the assembledfirst impeller 41, the assembledsecond impeller 42 and the assembledpositioning core sleeve 44 off. Meanwhile, theshaft limiting plate 851 in the shaft press-fitting jig is detached, and the first assembly is placed in the impeller groove in thewheel limiting seat 852. Then, theshaft stopper plate 851 is re-inserted into thesecond stopper guide 853 while theimpeller shaft 43 is inserted into theshaft stopper plate 851, and the lower end of theimpeller shaft 43 is inserted into the upper opening of thepositioning core 44 while theimpeller shaft 43 is coaxially and vertically aligned with the first assembly below. And finishing the initialization of the shaft press-fitting jig.

In addition, in order to further prevent theimpeller shaft 43 from being bent or broken due to the position deviation during the execution of the second punching operation, the height of the punchinghead 832 may be appropriately lowered so that the first shaft hole in the punchinghead 832 is sleeved on theimpeller shaft 43.

Then therotary bracket 82 rotates the punchingair hammer 83 to the second punching station; thepunch 832 is depressed to perform a second punching action so that theimpeller shaft 43 extends through theshaft mounting cavity 440 in thepositioning core housing 44 and the portions of theimpeller shaft 43 extending at both ends of thepositioning core housing 44 are of equal length. After the second stamping action is completed, the stampinghead 832 is raised. The operator or the robot removes theshaft stopper plate 851 and removes the second combination of the first combination of theimpeller shafts 43 having been assembled.

Then, themovable seat 852 in the extrusion jig is removed, the second assembly is sent into the first limit groove of the fixedseat 851 in the extrusion jig, and then themovable seat 852 is covered, so that the upper and lower extending parts of theimpeller shaft 43 in the second assembly are just inserted into the second shaft holes in the fixedseat 851 and themovable seat 852. And finishing the initialization of the pressurizing jig.

Next, thepunch 832 presses down for the third time to complete the third punching operation; deforming the chamferedstructure 441 into the same structure as the third segment of thepositioning core sleeve 44. After the punching operation is completed, the punchinghead 832 is lifted, and the operator or the robot removes the movable part to take out the assembleddual impeller assembly 4.

In this embodiment, when theplatform 81 is used as a polar coordinate plane and the mounting point of thebracket 821 is used as a pole, the adjacent polar angles among the first stamping station, the second stamping station and the third stamping station are 120 °, and the pole diameters from the center point to the pole of the three stamping stations are equal; and the three punching stations are sequentially arranged according to a preset clockwise or anticlockwise sequence.

The punching tool comprises a controller, and the controller is used for controlling the rotatingbase 822 to rotate 120 degrees at each time, so that the three punching stations are sequentially switched.

The pressure value and the stamping depth of the stampingair hammer 83 during stamping action execution on three stamping stations are different, and the controller is also used for controlling the stampingair hammer 83 to circularly switch the pressure value and the stamping depth of each stamping action, so that stamping action execution on different stamping stations according to the preset pressure value and the stamping depth corresponding to each station is realized.

The punching machine in the embodiment is used as semi-automatic equipment, the parameters of each punching are automatically set by control, and after the initialization of each jig is completed, operators of other equipment issue punching instructions to the controller.

In this embodiment, the periphery of the fixedseat 851 is provided with a plurality of third limiting guide rods extending vertically upwards, and the periphery of themovable seat 852 is provided with limiting guide holes which have the same positions as the third limiting guide rods and are matched with the apertures; themovable seat 852 is sleeved on the third limiting guide rod.

The peripheries of thefirst positioning seat 841, thesecond positioning seat 842, theshaft limiting plate 851, thewheel limiting seat 852, the fixedseat 851 and themovable seat 852 are all provided with connecting lugs which protrude outwards and are used for connecting limiting guide rods. And thefirst positioning seat 841 corresponds to the position of the connecting lug on thesecond positioning seat 842. Theshaft stopper plate 851 corresponds to the position of the engaging lug on thewheel stopper seat 852. The fixedseat 851 corresponds to the position of the engaging lug on themovable seat 852. The connecting lug on thefirst positioning seat 841 is fixedly connected with the firstlimit guide rod 843. The engaging lug of thewheel limiting seat 852 is fixedly connected with the second limitingguide rod 853. The engaging lug on the fixingbase 851 is fixedly connected with the third limiting guide rod. Limiting guide holes for the first limitingguide rod 843, the second limitingguide rod 853 or the third limiting guide rod to penetrate through are formed in connecting lugs in thesecond positioning seat 842, theshaft limiting plate 851 and themovable seat 852.

The tops of the first limitingguide rod 843, the second limitingguide rod 853 and the third limiting guide rod are provided with conical tips with gradually reduced outer diameters.

The rod bodies of the firstlimit guide rod 843 and the secondlimit guide rod 853 are also sleeved with return springs.

This embodiment is through setting up corresponding spacing guide arm outside each tool, restricts the direction of motion in the tool stamping process, avoids appearing the skew and leads to the product to scrap. Meanwhile, the reset spring can reset the jig again after the punching is finished every time, so that an operator or a mechanical arm can take out finished products or semi-finished products assembled in the jig conveniently.

Considering that thesecond positioning seat 842 needs to be assembled and disassembled frequently during the use process, in the present embodiment, handles protruding outwards are disposed on the outer sides of the left half seat and the right half seat in thesecond positioning seat 842. Thesecond positioning seat 842 can be conveniently taken down from the core sleeve press-fitting jig.

Meanwhile, the positions of the abutting surfaces of the left half seat and the right half seat are provided with locking bodies for alignment, and each locking body comprises a lock tongue and a lock groove which are respectively arranged on the left half seat and the right half seat. Thesecond positioning seat 842 can be assembled conveniently through the lock tongue and the lock groove structure, so that the assembling precision of the second positioning seat and the second positioning seat is ensured. Meanwhile, thesecond positioning seat 842 is prevented from being loosened in the stamping process, and the assembly precision of the product is effectively improved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. An anti-electromagnetic interference turbine flow meter, comprising:

the shell is of a tubular structure with a fluid channel inside, the fluid channel is in a straight-through type and comprises an inlet end and an outlet end, and the middle section of the fluid channel is a turbine cavity; a probe mounting groove is formed in the outer wall of the shell corresponding to the turbine cavity;

the front deflector is rotatably arranged at one side of the inlet end of the fluid channel in the shell, and the front deflector is coaxially arranged with the fluid channel;

the rear fluid director is rotatably arranged on one side of the outlet end of the fluid channel in the shell, and the rear fluid director and the fluid channel are coaxially arranged;

a double impeller assembly located within a turbine chamber of the fluid passageway; the dual impeller assembly comprises a first impeller, a second impeller and an impeller shaft; one end of the impeller shaft is rotatably connected to the front fluid director, and the other end of the impeller shaft is rotatably connected to the rear fluid director, and the impeller shaft, the front fluid director and the rear fluid director are coaxially arranged; the first impeller and the second impeller are identical turbines; the first impeller and the second impeller are arranged on the impeller shaft in the same direction in a sleeved mode at intervals, the impeller distance between the first impeller and the second impeller is an expert experience value, and the requirements are that: under the condition of the current impeller spacing, the balance coefficient of the fluid elastic disturbance generated between the adjacent impellers and the interference of the generated detectable electric signal is minimum; the installation angles of the first impeller and the second impeller on the impeller shaft have phase difference, and the blade phase deflection angle of the first impeller and the second impeller is larger than the minimum detectable impeller rotation angle and is less than or equal to 15 degrees;

the detection probe is positioned in the probe mounting groove; the detection probe comprises a first probe and a second probe, and the first probe and the second probe are respectively used for receiving feedback signals generated by the first impeller and the second impeller in the turbine cavity along with the movement of the fluid; the distance and the relative position relation between the first probe and the first impeller are completely the same as those between the second probe and the second impeller; and

the signal converter is used for acquiring feedback signals received by the first probe and the second probe and outputting corresponding flow detection data according to the feedback signals; the data processing process of the signal converter comprises the following processes: taking a feedback signal acquired by one probe as a detection signal, and taking the other probe as a correction signal; converting the detection signal and the correction signal into square pulses A and B, respectively, starting a timer at each rising edge of the square pulse A, and starting a timer at each nearest signal of the square pulse BStopping the timer at the rising edge to obtain a time difference Ti; comparing the time difference Ti with a preset time interval T, and making the following judgment and decision: when Ti belongs to T, judging that the current signal is a noise signal, and not counting the current pulse signal; (2) when in use

Judging a current signal to be a non-noise signal, and counting a current pulse signal; finally, calculating and outputting a corresponding flow detection result Q according to the current meter coefficient K of the turbine flowmeter and the recorded pulse signal frequency f; wherein Q is K · f.

2. The anti-electromagnetic interference turbine flow meter of claim 1, wherein: in the double-impeller component, the impeller distance d between two impellers and the outer diameter R of the impeller form a negative correlation relationship, and form a positive correlation relationship with the number n of blades of each impeller.

3. The anti-electromagnetic interference turbine flow meter of claim 2, wherein: for a double-impeller assembly with a specific specification, the method for determining the optimal impeller distance between two impellers comprises the following steps:

(1) fitting a response function eta (d) between a fluid elastic disturbance effect eta generated between the two impellers and an impeller distance d under a preset standard fluid environment;

(2) fitting a response function mu (d) between the interference effect mu of the feedback signals between the two impellers and the impeller distance d under the detection condition of a standard detection probe;

(3) calculating a balance coefficient phi between the fluid disturbance and the signal disturbance according to the following formula:

Φ(d)＝α·η(d)+β·μ(d)

in the above formula, α represents the weight of the influence of the fluid elastic disturbance effect on the detection accuracy of the flowmeter; beta represents the influence weight of the signal interference effect on the detection precision of the flowmeter;

(4) minimum value of calculated balance coefficient phi_minThe corresponding impeller distance d is the optimal impeller space in the double-impeller assembly with the current specificationDistance.

4. The anti-electromagnetic interference turbine flow meter of claim 1, wherein: in the double-impeller assembly, the vane phase deviation angle theta of the first impeller and the second impeller satisfies the following condition:

wherein a represents the minimum detectable impeller rotation angle, in particular the minimum impeller rotation angle detectable by a detection probe in the current turbine flowmeter; min {. is } represents taking a minimum function; n represents the number of blades in each impeller.

5. The anti-electromagnetic interference turbine flow meter of claim 1, wherein: the probe mounting groove comprises a first groove and a second groove; the first probe is positioned in a first groove, the second probe is positioned in a second groove, and the distance between the first groove and the second groove is determined according to the impeller distance between a first impeller and a second impeller in the double-impeller assembly so as to satisfy the following conditions: the first probe and the second probe which are arranged in the first groove and the second groove keep constant phase difference of detection signals or the phase difference meets the requirement of error limit under the standard detection state without magnetic field interference.

6. The anti-electromagnetic interference turbine flow meter of claim 5, wherein: the shape of the detection probe is matched with that of the probe mounting groove, and the detection probe and the probe mounting groove are assembled by adopting a direct insertion type mounting method; and the detection probe is fixedly connected with the shell through a locking bolt.

7. The anti-electromagnetic interference turbine flow meter of claim 1, wherein: the shell is made of a non-magnetic conductive material; the blades are made of magnetic materials.

8. The anti-electromagnetic interference turbine flow meter of claim 1, wherein: the detection probe comprises a permanent magnet and a coil, the permanent magnet is used for generating a magnetic field near the corresponding impeller, and the coil is used for receiving a feedback signal generated by cutting magnetic induction lines of the magnetic field in the rotating process of the impeller in the double-impeller component.

9. The anti-electromagnetic interference turbine flow meter of claim 1, wherein: when the outer diameter of the impeller in the turbine flowmeter is 40-50mm and the number of blades of a single impeller is 8, the impeller interval in the double-impeller component is 5mm, and the phase deviation angle of the blades of the impeller is 15 degrees.

10. The anti-electromagnetic interference turbine flow meter of claim 1, wherein: an impeller shaft in the double-impeller component is connected with the front flow guider or the rear flow guider through a bearing; and sealing flanges for connecting pipelines are arranged in the positions, corresponding to the inlet end and the outlet end of the fluid channel, in the shell.

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