An insertable electromagnetic flowmeter suitable for battery operation

Abstract

The application provides a battery-powered plug-in electromagnetic flowmeter, comprising a probe shell, an inner magnetic conducting rod, an inner magnetic conducting rod insulating plug, a winding and electrode isolation plug, a winding and electrode lead-out line cavity, a winding lead-out lining flat washer and a winding tail magnetic conducting plug. The application adopts a T-shaped tee structure to establish a self-shielding stable magnetic circuit, ensuring measurement stability; adopts an insulating film plating method on the surface of a magnetic material to realize pipeline insulation and reduce excitation current; increases a conversion drive from magnetization to constant magnetism, measurement and magnetic energy recovery, and monitors excitation current by using a single-chip component, realizes seamless transition of the excitation magnetization stage and the constant magnetism stage, reduces resistance consumption in the excitation process, realizes that excitation power consumption is reduced to 15-20 uA under the condition of positive-negative excitation period measurement in a 2-second interval, and high precision with an R ratio of 1:500 can be obtained. The application has the characteristics of simple structure, energy saving and strong stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic equipment, in particular to an insertion type electromagnetic flowmeter suitable for battery power supply. BACKGROUND

[0002] The electromagnetic flowmeter is a flow metering device for realizing flow rate detection by using electromagnetic induction principle. In the prior art, in the flow measurement with water as the medium, the electromagnetic flowmeter has a significant shortcoming that polarization effect exists in the electrode in water, and the polarization voltage is much higher than the induced electromotive force. In order to overcome this shortcoming, a better solution is to use alternating excitation, and the difference between the measurement values at the two ends of the electrode in the positive and negative excitation is used to calculate the induced electromotive force, so that the potential difference caused by polarization can be eliminated. This is a general method used in the electromagnetic flowmeter for measuring water flow. However, this will bring a new problem that the flowmeter excitation needs to use a coil (electromagnet), and a permanent magnet cannot be used, thereby resulting in large power consumption of the electromagnetic flowmeter, which is not suitable for battery power supply application. With the development of the information age, the Internet of Things has become a common demand of the society, and the mechanical household water meter in the prior art has a large shell volume, a large weight, and consumes a large amount of brass, which causes the problem of high production cost. In addition, the Internet of Things of the mechanical water meter needs to solve the conversion from mechanical display to electronic reading, that is, the so-called "electromechanical conversion", and the current electromechanical conversion still has many problems. Therefore, it is necessary to propose a new invention to solve the above two problems. SUMMARY

[0003] The present application aims to provide an insertion type electromagnetic flowmeter suitable for battery power supply, so as to solve the problems of large power consumption and high cost of the existing flowmeter.

[0004] The present application provides an insertion type electromagnetic flowmeter suitable for battery power supply, which comprises a probe shell, an inner magnetic guide rod, an inner magnetic guide rod insulation plug, a winding and electrode isolation plug, a winding and electrode lead-out line cavity, a winding lead-out lining flat washer, and a winding tail magnetic guide plug.

[0005] The probe shell is located outside the insertion type electromagnetic flowmeter, the inner magnetic guide rod is vertically installed at the center position inside the device, the inner magnetic guide rod insulation plug is sleeved and installed outside the inner magnetic guide rod, the winding and electrode isolation plug is installed on the lower surface of the inner magnetic guide rod insulation plug, the winding lead-out lining flat washer is installed inside the bottom of the probe shell, the winding tail magnetic guide plug is installed on the lower surface of the winding lead-out lining flat washer, and the winding and electrode isolation plug and the winding lead-out lining flat washer form the winding and electrode lead-out line cavity between them.

[0006] Further, the probe shell is composed of three communicating cavities, namely flow channel cavity, isolation cavity, winding and electrode wire leading-out cavity, and a self-shield stable magnetic circuit is established through the three-way structure to shield external magnetic field interference and ensure measurement stability.

[0007] Further, the probe shell, inner magnetic rod and winding tail magnetic plug are made of materials with good magnetic conductivity and have the ability to resist violent mechanical impact, and therefore are preferably made of metallic magnetic materials, such as iron-nickel alloy and industrial pure iron.

[0008] Further, the part of the probe shell, inner magnetic rod and measurement medium (water) in contact, namely the measurement flow channel, needs to be insulated, and the present application realizes the insulation of the measurement flow channel by using the method of high-temperature spraying ceramic insulation layer or vacuum evaporation of parylene organic insulation film.

[0009] Further, the inner magnetic rod is wound with an enameled wire winding, and the outside of the winding has electrode leading-out wires.

[0010] Further, waterproof gaskets or waterproof glue are needed between the inner magnetic rod insulation plug and the inner magnetic rod and the probe shell.

[0011] Further, two electrodes are embedded in the winding and electrode isolation plug, and O-shaped rubber rings are used to realize sealing between the electrodes and the inner magnetic rod insulation plug, and the method of filling gaps with silicone can also be used to realize sealing.

[0012] Further, the electrode outside is led out by spot welding method, and the electrode leading-out wire first vertically passes through the leading-out hole, and then is bent along the leading wire channel on the winding and electrode isolation plug to enter the inside of the winding and electrode leading-out wire cavity.

[0013] Further, the winding tail magnetic plug is symmetrically distributed with four wire passing holes at a certain distance from the center.

[0014] Further, the top of the inner magnetic rod is a spherical head, and the spherical head and the probe shell form a flow channel.

[0015] Further, the probe shell and the inner magnetic rod are treated by the method of thermal spraying ceramic insulation film or vacuum evaporation of parylene organic film to realize insulation of the measurement flow channel.

[0016] Further, the probe shell has electrode guide grooves on both sides, and the upper part of the probe shell has a sealing pad recess at the butt joint position with the magnetic inner rod.

[0017] Further, the inner magnetic guide rod insulation plug is processed with a small hole, the inner magnetic guide rod passes through the hole and extends into the winding and electrode lead-out line cavity. Two electrode lead-through holes are opened on both sides of the hole, the two holes are opposite to the electrode holes on the inner magnetic guide rod insulation plug, and two positioning pins are processed on the other two sides of the magnetic rod through hole.

[0018] Further, the thickness of the winding lead-out lining washer is 0.25mm, which is slightly larger than the diameter of the winding enameled wire.

[0019] Further, the inner magnetic guide column is embedded in the winding tail magnetic guide plug, the inner diameter of the magnetic guide column is consistent with the tail inner diameter of the probe shell, and the magnetic guide column is in contact with the probe shell.

[0020] Further, the working circuit of the application includes an excitation drive circuit, and the working process (excitation algorithm) of the excitation drive circuit includes five steps:

[0021] (1) The forward excitation magnetic field establishment stage initializes the pins corresponding to the "forward excitation drive" and "negative excitation drive" of the single-chip microcomputer to the output mode, and outputs high level for the "forward excitation drive" and low level for the "negative excitation drive";

[0022] (2) The single-chip microcomputer releases the excitation right to U2 to take over the excitation, during the magnetization, the single-chip microcomputer needs to perform ADC sampling on the "excitation current ADC" signal, when the excitation current value sampled by the single-chip microcomputer approaches the set target, the single-chip microcomputer needs to release the control of the excitation and hand over the control right to U2, and the feedback action of U2 is used to realize "constant current excitation", according to Ampere's law, the loop integral of the magnetic field strength is proportional to the current value surrounded by the loop, therefore, constant current excitation is also "constant magnetic field". The method for the single-chip microcomputer to hand over the excitation control right to U2 is to configure the "forward excitation drive" pin as high-impedance input, at this time, R3 right side is floating, and the gate of N1 is controlled by U1 through R9;

[0023] (3) The constant magnetic field measurement stage adopts 12-bit 1Mhz sampling rate ADC, 16 times oversampling, and the ADC is configured as 500Khz rate (reduced index), the sampling time is 512uS, plus the stable time delay after U2 takes over the excitation, the constant magnetic field stage consumes a total of 562uS;

[0024] (4) magnetic field energy recovery phase, the single-chip microcomputer first initializes the pin corresponding to "forward excitation drive" to output, and the output is 0, delays a time Td, Td is also called dead time control time, then the pin corresponding to "negative excitation drive" outputs high, after entering this driving state, P1, N2 is turned on, in this driving state, the winding current direction does not change, but the current loop is provided by P1, N2, R7, and the current direction of R7 is reversed, if U1 adopts positive and negative power supply, its output should be negative, but since U1 adopts single-ended power supply, therefore U1 output = 0, since P1, N2 is in the driving state, the internal resistance is small, therefore the magnetic field energy can be recovered to the maximum extent, the single-chip microcomputer should always sample the excitation current ADC until the sampling value is no longer 0, indicating that the magnetic field energy recovery is completed, the excitation current is amplified by U1, then the single-chip microcomputer ADC is used to measure the excitation current, and the single power supply characteristic of the operational amplifier is used, once the ADC result is detected to be not 0, it is indicated that the excitation energy recovery is completed, and the present application can recover all the magnetic energy;

[0025] (5) negative excitation, the process of negative excitation, and the measurement process, and the magnetic field energy recovery process is the same as the positive, and will not be repeated.

[0026] The application has the following beneficial effects: the application provides an insertion type electromagnetic flowmeter suitable for battery power supply, comprising a probe shell, an inner magnetic guide rod, an inner magnetic guide rod insulation plug, a winding and electrode isolation plug, a winding and electrode lead-out line cavity, a winding lead-out lining flat washer and a winding tail magnetic guide plug. The application firstly improves the structure of the insertion type electromagnetic flowmeter, adopts a T-shaped tee structure to establish a self-shielding stable magnetic circuit, ensures measurement stability, adopts an insulation film plated on the surface of a magnetic material to realize pipeline insulation and reduce excitation current, increases conversion driving from magnetization to constant magnetism, measurement and magnetic energy recovery, uses a single-chip component to monitor excitation current, realizes seamless transition of the excitation magnetization stage and the constant magnetism stage, reduces resistance consumption in the excitation process, and the field effect tube of the driving branch arm is fully turned on with small internal resistance, the magnetization time is very short, and there is no additional resistance consumption, while in the magnetic energy recovery stage, the field effect tube of the other branch arm is fully turned on with small internal resistance, the recovery time period, and there is no additional resistance consumption, and the single power supply characteristic of the operational amplifier is used to judge the completion of the recovery through the non-zero ADC, to avoid over-driving (over-driving will lead to reverse magnetization), these improvements simplify the circuit and reduce power consumption. The traditional electromagnetic flowmeter must be excited twice for each measurement, and is changed into once positive excitation measurement, delayed for 2 seconds, and then negative excitation measurement, compared with the positive and negative measurement with a 2-second cycle, the process change saves half of the energy. The application can reduce the power consumption to 15-20uA, which has met the demand of full electronic household water meter, if equipped with a 26505E type lithium sub-battery, the nominal capacity of the battery is 9000mA.h, and according to the available capacity of 75%, it is 6750mA.h, which can support the water meter for 337500 hours = 38 years. Although the insertion type electromagnetic flowmeter of the application has the characteristics of high precision and long service life, it has better cost advantage compared with the ordinary mechanical water meter, because the shell of the mechanical water meter is large in size, heavy in weight and consumes a lot of brass, so the cost is high. If the electromagnetic flowmeter of the application is used for the manufacture of DN15 water meter, the cost will be greatly reduced, and the application has the characteristics of simple structure, energy saving and strong stability. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0028] Figure 1 The application provides an insertion type electromagnetic flowmeter probe cross-sectional view suitable for battery power supply.

[0029] Figure 2 A schematic diagram of a battery-powered electromagnetic flowmeter excitation drive circuit is provided.

[0030] Figure 3 A battery-powered electromagnetic flowmeter probe is provided.

[0031] Figure 4 A battery-powered electromagnetic flowmeter magnetically permeable inner rod is provided.

[0032] Figure 5 A battery-powered electromagnetic flowmeter magnetically permeable inner rod is provided.

[0033] Figure 6 A battery-powered electromagnetic flowmeter winding wire outlet lining flat washer is provided.

[0034] Figure 7 A battery-powered electromagnetic flowmeter winding wire tail magnetically permeable plug is provided.

[0035] Figure 8 A battery-powered electromagnetic flowmeter winding wire and electrode isolation plug is provided.

[0036] Illustration: 1-probe shell; 2-magnetically permeable inner rod; 3-magnetically permeable inner rod insulation plug; 4-winding wire and electrode isolation plug; 5-winding wire and electrode lead-out line cavity; 6-winding wire outlet lining flat washer; 7-winding wire tail magnetically permeable plug. DETAILED DESCRIPTION

[0037] As shown in Figures 1 to 2 the embodiment of the present application provides a battery-powered electromagnetic flowmeter, comprising: probe shell 1, magnetically permeable inner rod 2, magnetically permeable inner rod insulation plug 3, winding wire and electrode isolation plug 4, winding wire and electrode lead-out line cavity 5, winding wire outlet lining flat washer 6, winding wire tail magnetically permeable plug 7.

[0038] The probe shell 1 is made of a material with good magnetic conductivity, and the current ideal materials are industrial pure iron (soft iron), permalloy, silicon steel and high-density ferrite. The probe shell 1 is composed of three communicating cavities, a first flow channel cavity, a second isolation cavity and a third winding and electrode wire leading-out cavity 5. The flow channel cavity firstly provides a channel for fluid flow, and then the outer wall of the cavity forms a part of the magnetic circuit; the isolation cavity is internally embedded with an inner magnetic conducting rod insulation plug 3 and a winding and electrode isolation plug 4, and the water and electricity isolation of the electromagnetic flowmeter is realized in the cavity. The winding and electrode wire leading-out cavity is internally provided with a magnetic rod part of the inner magnetic conducting rod 2, the magnetic rod part is wound with an enameled wire winding, and the electrode leading-out wire is provided outside the winding. The part of the probe shell in contact with the fluid is extended by a certain length, and the surface is subjected to insulation treatment. In order to minimize the length of the "air magnetic circuit", the application adopts a completely different pipeline insulation treatment from the traditional electromagnetic flowmeter: a first preferred solution is to adopt a ceramic thermal spraying process to form a dense ceramic film with a thickness of 20-100 uM on the metal surface, adopt alumina ceramic thermal spraying, and spray twice to obtain a ceramic film with a thickness of about 50 uM; a second preferred solution is to adopt vacuum evaporation of parylene organic film, adopt parylene-C material, and obtain a dense insulation film with a thickness of about 100 uM.

[0039] The inner magnetic conducting rod 2 is composed of two parts: a first part extending into the flow channel cavity of the probe shell, called "hemispherical magnetic pole", and a second part extending into the "magnetic rod" of the "winding and electrode leading-out wire cavity" of the probe shell. The "hemispherical magnetic pole" and the outer wall of the "probe shell flow channel cavity" form a radial magnetic field, which is the measurement magnetic field of the electromagnetic flowmeter. The "magnetic rod" is wound with an excitation winding for establishing the magnetic field used by the electromagnetic flowmeter. In the application, in order to minimize the internal resistance of the winding, it is necessary to minimize the length of each turn of the winding, so the diameter of the "magnetic rod" is very small, and the winding is directly wound on the "magnetic rod". The diameter of the sample magnetic rod part is only 3 mm, the winding is 4500 turns, and the average length is only 31 mm, which maximally reduces the resistance of the winding.

[0040] The inner magnetic conducting rod insulation plug 3 is made of plastic material, and the inventor adopts PPO injection molding to manufacture the part. The advantages of PPO are: resistance to hydrolysis, high molding precision and moderate cost. Other hydrolysis-resistant injection molding materials such as nylon can also be used, and ceramics can also be used. The first function of the inner magnetic conducting rod insulation plug is to support the inner magnetic conducting rod 2; the second function is to provide a channel for the electrode to extend into the fluid; the third function is to isolate the fluid flow channel from the winding to achieve water and electricity isolation. A waterproof gasket or waterproof glue is needed between the inner magnetic conducting rod insulation plug, the inner magnetic conducting rod 2, the "electrode" and the probe shell 1. Two electrodes are embedded in the inner magnetic conducting rod insulation plug 3, and the electrode leading-out wire conflicts with the winding, so the application designs a winding and electrode isolation plug 4 to obtain a special electrode leading-out wire channel.

[0041] The winding and electrode lead-out line cavity 5 is a part of the probe shell 1. Inside the cavity, the internal "magnetic rod" is made of an excitation winding of enameled wire, and a 0.5-0.8 mm gap is left between the winding and the cavity inner wall for the electrode lead-out line. The winding lead-out lining washer 6 is formed by die stamping of a polyester film and is pasted on the side of the winding tail magnetic conductive plug 7 close to the winding. The purpose is to line the winding lead-out line along the radial direction. The purpose of this is to ensure that the winding is uniformly compacted. Uniform compaction of the winding is the key to saving the total length of the winding. One of the skills of the present application is to reduce the total length of the winding while ensuring the total number of turns of the winding, thereby reducing the DC resistance of the winding.

[0042] The winding tail magnetic conductive plug 7 is made of a magnetic conductive material and is consistent with the material of the probe shell 1 and the magnetic conductive inner rod 2. The plug is part of the total magnetic circuit and has two functions. First, it serves as a tail baffle for the winding, forming a fixed winding space. Second, it guides the magnetic field at the tail of the "magnetic rod" into the "probe shell", guiding the magnetic field into the "effective excitation" air magnetic circuit, i.e. the "air magnetic circuit" (magnetic gap) between the probe shell flow cavity and the magnetic conductive inner rod ball head. The winding tail magnetic conductive plug is fixed to the tail of the "magnetic rod" by adhesion. The winding tail magnetic conductive plug 7 has four wire holes drilled at a certain distance from the center and symmetrically distributed.

[0043] Circuit principle:

[0044] The main circuit of the excitation circuit is an H-bridge of field effect transistors. This is a general design. To correctly describe the principle of the present application, the H-bridge circuit needs to be further explained.

[0045] The upper two arms of the H-bridge are P-channel devices, respectively P1 and P2. The lower two arms of the H-bridge are N-channel devices, respectively N1 and N2. P1 is driven by the opposite N2 device, R1 provides pull-up drive for P1, and R5 is connected to N2.D, which is driven by N2. P2 is driven by the opposite N1 device, R2 provides pull-up drive for P1, and R6 is connected to N1.D, which is driven by N1. The winding is connected to the middle of the H-bridge. When P1 and N2 are turned on, the winding current flows from left to right. When P2 and N1 are turned on, the current flows from right to left, achieving excitation in two directions. The gate drive of N1 has two sources: first, the "forward excitation drive", which comes from the single-chip microcomputer pin. The single-chip microcomputer is a known device and is not given in the circuit. This signal is connected to the gate of N1 through R3. The second source is the output terminal 1 of operational amplifier U2, which is connected to the gate of N1 through R9.

[0046] The gate drive of N2 has two sources: the first is "negative excitation drive", the signal comes from the single-chip microcomputer pin, the single-chip microcomputer is a known device, and the circuit is not given, and the signal is connected to the gate of N2 through R4; the second is from the output end 1 of the operational amplifier U2, and is connected to the gate of N2 through R8. R7 is an excitation current sampling resistor, U1 constitutes a 101 times amplifier, which can amplify the excitation current signal by 101 times, one way of the output of U1 is connected to the ADC pin of the single-chip microcomputer, and the signal is named "excitation current ADC", and the single-chip microcomputer is not drawn in this document, which is a known device; the other way of the output of U1 is connected to the negative input end of U2 to provide negative feedback for U2. U2 constitutes a negative feedback amplifier, the positive input of U2 is "excitation current setting", the negative input is connected to the output of U1, and the output of U1 is the current sampling signal Vr1*101, Vr1 is the voltage across R1=I*R1, I is the excitation current, and the output of U1=I*R1*101. According to the working principle of the operational amplifier, when U2 receives the excitation drive, under the action of negative feedback, U2 will adjust the excitation current to: I*R1*101="excitation current setting" Therefore, the size of the excitation current can be controlled by the "excitation current setting" voltage, if the excitation current is fixed, a voltage can be provided by a voltage dividing resistor, if the excitation current can be freely adjusted, a voltage can be provided by a DAC. E1 is a lithium capacitor, which is a new product composed of a lithium battery and an electrolytic capacitor. Its characteristics are similar to those of a lithium battery, but its leakage current is much smaller than that of a lithium battery, about uA level, and its charge and discharge life is much longer than that of a lithium battery. Its specific role will be described below. BAT1 is a lithium battery, and the inventor uses 26505E type lithium battery as a sample power supply. The working process (excitation algorithm) of the above circuit is as follows:

[0047] First step, forward excitation magnetic field establishment stage

[0048] The pins corresponding to "forward excitation drive" and "negative excitation drive" of the single-chip microcomputer are initialized as output mode, and "forward excitation drive" outputs high level and "negative excitation drive" outputs low level. At this time, no matter what voltage U2 outputs, N1 is driven to be on and N2 is cut off due to the large resistance value of R8 and R9 (10K) and the small resistance value of R3 and R4 (200 ohm), and meanwhile P1 is cut off and P2 is on, so that the right positive and left negative excitation winding is driven. In the application, the large difference between the resistances is utilized to realize the switching of the single-chip microcomputer drive and the operational amplifier drive excitation. When the single-chip microcomputer port line is configured as output, the excitation control is determined by the single-chip microcomputer due to the small drive resistance of the single-chip microcomputer and the 200 ohm resistance of R3 and R4, and the effect of U2 is shielded. During this period, N1 is fully driven, so that P2 and N1 are fully on and the internal resistance is very small, and the battery voltage is almost applied to both ends of the excitation winding, so that the winding is rapidly excited and the excitation time can be estimated by L*di / dt=3.6V. In the second step, the single-chip microcomputer releases the excitation right and U2 takes over the excitation

[0049] During the excitation, the single-chip microcomputer needs to perform ADC sampling on the "excitation current ADC" signal. When the excitation current value sampled by the single-chip microcomputer approaches the set target, the single-chip microcomputer needs to release the control of the excitation and hand over the control right to U2. The feedback effect of U2 is utilized to realize constant current excitation, and according to Ampere's law, the magnetic field strength loop integral is proportional to the current value surrounded by the loop, so that the constant current excitation is also constant magnetic field. The method of the single-chip microcomputer handing over the excitation control right to U2 is to configure the "forward excitation drive" pin as high resistance input, so that R3 on the right is floating and the gate of N1 is controlled by U1 through R9. After U2 takes over the excitation, the output voltage value of U2 adjusts the D-S resistance of N1, and finally the current is stabilized to I*R1*101="excitation current setting". From the takeover of U2 to this state, it takes about 10-50uS, so that the single-chip microcomputer releases the excitation right and delays for at most 50uS to enter the constant magnetic field state, and the output voltage of the electrode loop can be measured.

[0050] The third step is the constant magnetic field measurement stage

[0051] In order to reduce power consumption, the single-chip microcomputer should complete the measurement of the electrode loop voltage as soon as possible. The inventor adopts 12-bit 1Mhz sampling rate ADC, 16 times oversampling, and configures the ADC as 500Khz rate (reduced index), and the sampling time is 2uS*16*16=512uS. In addition to the stable time delay after U2 takes over the excitation, the constant magnetic field stage consumes a total of 562uS. In the constant magnetic field stage, the magnetic field has been stabilized and no longer stores energy, so the excitation consumption in this time cannot be recovered, and therefore the shorter the constant magnetic field time is, the lower the power consumption is.

[0052] The fourth step is the magnetic field energy recovery stage

[0053] The single-chip computer firstly initializes the pin corresponding to the "forward excitation drive" as output and outputs 0, delays a time Td, which is also called dead time control time, to avoid the upper and lower direct through of the bridge, and then outputs high level to the pin corresponding to the "negative excitation drive", enters this driving state, P1, N2 is turned on, in this driving state, the winding current direction does not change, but the current loop is provided by P1, N2, R7, and the current direction of R7 is reversed, if U1 is powered by positive and negative power supply, its output should be negative, but since U1 is powered by single-ended, therefore U1 output = 0, since P1, N2 is in the driving state, the internal resistance is small, therefore the magnetic field energy can be maximally recovered, during which the single-chip computer needs to always sample the excitation current ADC until the sampling value is no longer 0, indicating that the magnetic field energy recovery is completed. The excitation current is amplified by U1, then the single-chip computer ADC measures the excitation current, and uses the single power supply characteristic of the operational amplifier, once the ADC result is detected to be not 0, it indicates that the excitation energy recovery is completed, the present application can recover all the magnetic energy. During the magnetic field energy recovery process, attention also needs to be paid to a key device: E1, E1 is a lithium capacitor, which allows external current to be reversed to charge the device, in the case of small charging capacity, the terminal voltage of E1 remains unchanged, this feature makes it possible to recover the magnetic energy of the electromagnetic flowmeter powered by a disposable lithium battery, the disposable lithium battery (mainly lithium thionyl chloride battery) is strictly not allowed to be reversed, if the disposable lithium battery is repeatedly charged, the battery will be damaged, but the existence of E1 makes it possible to recover the magnetic energy. Another way to recover the magnetic energy is to parallel a large electrolytic capacitor across the battery BAT1, but the recovered magnetic energy will still cause the voltage of the electrolytic capacitor to rise by tens of mV, which will still damage the disposable lithium battery and reduce its service life, therefore, the parallel connection of the lithium capacitor in the power supply circuit is a key technology for magnetic energy recovery.

[0054] Fifth step, negative excitation

[0055] The process of negative excitation, as well as the measurement process and the magnetic field energy recovery process, is the same as the positive direction, and will not be repeated here.

[0056] The above only describes the preferred embodiments of the present application and is not used to limit the present application, for those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A battery powered insertion electromagnetic flow meter, characterized in that, It includes: The probe shell (1), the inner magnetic guide rod (2), the inner magnetic guide rod insulation plug (3), the winding and electrode isolation plug (4), the winding and electrode lead-out line cavity (5), the winding lead-out lining flat washer (6), the winding tail magnetic guide plug (7); The probe shell (1) is located outside the plug-in electromagnetic flowmeter, the inner magnetic guide rod (2) is vertically installed at the center position inside the device, the inner magnetic guide rod (2) is sleeved and installed with the inner magnetic guide rod insulation plug (3) outside, the inner magnetic guide rod insulation plug lower surface is installed with the winding and electrode isolation plug (4), the probe shell (1) bottom inner side position is installed with the winding lead-out lining flat washer (6), the winding lead-out lining flat washer (6) lower surface is installed with the winding tail magnetic guide plug (7), the winding and electrode isolation plug (4) and the winding lead-out lining flat washer (6) form the winding and electrode lead-out line cavity (5) between the regions, the working circuit suitable for the battery-powered plug-in electromagnetic flowmeter, including the excitation circuit, the main circuit of the excitation circuit including the H bridge of the field effect tube; The upper two arms of the H bridge are P channel devices, respectively P1 and P2, the lower two arms of the H bridge are N channel devices, respectively N1 and N2, P1 is driven by the opposite N2 device, R1 provides pull-up drive for P1, the two ends of R1 are connected to the source and gate of P1 respectively, R5 is connected to the drain of N2 (N2.D), the other end of R5 is connected to the gate of P1, P2 is driven by the opposite N1 device, R2 provides pull-up drive for P2, the two ends of R2 are connected to the source and gate of P2 respectively, one end of R6 is connected to the drain of N1, the other end of R6 is connected to the gate of P2, the winding is connected to the middle of the H bridge, when P1 and N2 are turned on, the current flows from the left end of the winding to the right end, when P2 and N1 are turned on, the current flows from the right end of the winding to the left end; The gate drive of N2 has two sources: first, the negative excitation drive signal, the negative excitation drive signal comes from the single-chip microcomputer pin, the negative excitation drive signal is connected to the gate of N2 through R4; The second way is the output signal of operational amplifier U2, U2 output is connected to the gate of N1 through R9 and to the gate of N2 through R8, one end of R7 is grounded, the other end of R7 is connected to the positive input end of U1, the source of N1 and the source of N2 respectively, U1 is an amplifier, one way of the output of U1 is connected to the ADC pin of the single-chip microcomputer; the other way of the output of U1 is connected to the negative input end of U2, providing negative feedback for U2, U2 constitutes a negative feedback amplifier, the positive input of U2 is set for excitation current, and the negative input is connected to the output of U1.

2. A battery powered insertion electromagnetic flow meter according to claim 1, characterized in that, The probe shell (1) is a T-shaped structure of a communication tubular body, and its internal cavity can be divided into three parts according to the function, which are flow channel cavity, isolation cavity and winding and electrode lead-out cavity.

3. A battery powered insertion electromagnetic flow meter according to claim 2, wherein, The outer side of the inner magnetic guide rod (2) is wound with enameled wire winding, and the outer side of the winding has electrode lead-out wire, and the surface of the part of the probe shell (1) in contact with the fluid is insulated.

4. A battery powered insertion electromagnetic flow meter according to claim 3, wherein, The inner magnetic guide rod (2) is wound with excitation winding.

5. A battery powered insertion electromagnetic flow meter according to claim 4, wherein, The inner magnetic guide rod insulating plug (3) and the inner magnetic guide rod (2), and the probe shell (1) need to be added with waterproof gaskets or waterproof glue.

6. A battery powered insertion electromagnetic flow meter according to claim 5, wherein, Two electrodes are embedded in the winding and electrode isolation plug (4), and the electrodes and the inner magnetic guide rod insulating plug (3) are sealed by O-shaped rubber rings or filled with silicone to realize sealing.

7. A battery powered insertion electromagnetic flow meter according to claim 6, wherein, The electrode leads are introduced by spot welding on the outside of the electrode, and the electrode leads are first vertically inserted into the lead hole, and then bent along the lead channel on the winding and electrode isolation plug (4) into the winding and electrode lead cavity (5).

8. A battery powered insertion electromagnetic flow meter according to claim 7, wherein, The winding tail magnetic guide plug (7) is provided with four wire holes.

9. A battery powered insertion electromagnetic flow meter according to claim 8, wherein, The top of the inner magnetic guide rod (2) is a spherical head, and a flow channel is formed between the spherical head and the probe shell (1). The probe shell (1) and the inner magnetic guide rod (2) are treated by thermal spraying insulation film or vacuum evaporation of parylene. The probe shell (1) has electrode guide grooves on both sides, and the probe shell (1) has a sealing pad recess at the upper joint position with the inner magnetic guide rod (2). A small hole is processed in the middle of the inner magnetic guide rod insulating plug (3), and the inner magnetic guide rod (2) is inserted into the winding and electrode lead cavity (5) through the hole. Two electrode lead wire holes are opened on both sides of the hole, and the two holes are opposite to the electrode hole on the inner magnetic guide rod insulating plug (3). Two positioning pins are processed on the other two sides of the magnetic guide rod hole. The winding lead gasket (6) has a thickness of 0.25mm, which is slightly larger than the diameter of the winding enameled wire. The winding tail magnetic guide plug (7) is embedded with a magnetic guide column, and the magnetic guide column is consistent with the inner diameter of the tail of the probe shell (1) and contacts the probe shell (1).

10. A battery powered insertion electromagnetic flow meter according to claim 9, wherein, The working process of the excitation circuit includes the following steps: First step, forward excitation magnetic field establishment stage, initialize the corresponding pins of the single-chip microcomputer forward excitation drive and negative excitation drive to output mode, output high level for forward excitation drive and low level for negative excitation drive; Second step, the single-chip microcomputer releases the excitation control right to U2, in the magnetizing stage, the single-chip microcomputer needs to sample the excitation current ADC signal, when the single-chip microcomputer samples the excitation current value close to the set target, the single-chip microcomputer needs to release the control of excitation and hand over the control right to U2, using the negative feedback of U2, configuring the forward excitation drive pin as high resistance input, and using U1 to control the gate of N1 through R9, using the output and input state switching of the single-chip microcomputer pin to realize the handover of excitation control right; Third step, constant magnetic measurement stage, after U2 takes over the excitation control right, the magnetic field enters the constant stage; Fourth step, magnetic field energy recovery stage, the single-chip microcomputer first initializes the corresponding pin of the forward excitation drive to output and outputs 0, and then delays for a time Td, and then the corresponding pin of the negative excitation drive outputs high level; Fifth step, negative excitation, the process of negative excitation, and the measurement process, and the magnetic field energy recovery process are the same as the forward excitation.

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