阅读说明：本技术 一种用于电磁水表的永磁式励磁方法及其电磁水表 (Permanent magnet type excitation method for electromagnetic water meter and electromagnetic water meter thereof ) 是由 钱金凤 刘宏亮 邱杰 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种用于电磁水表的永磁式励磁方法及其电磁水表,永磁体产生与水流体流速方向、信号电极连线方向相互正交的工作磁场,流量由信号电极检出,进入前置放大电路,由前置放大器电路完成阻抗匹配和差分放大,再送入信号处理电路,信号处理电路完成信号调理后,将处理好的信号送入微处理器电路,由微处理器电路完成流量的计算,由显示器完成流量显示。本发明通过在非采样周期内使信号电极与大地相连,释放流体的极化电势,消除永磁励磁的致命缺陷,使永磁式励磁得以应用在电磁水表上。(The invention discloses a permanent magnetic excitation method for an electromagnetic water meter and the electromagnetic water meter thereof, wherein a permanent magnet generates a working magnetic field which is orthogonal to the flow velocity direction of water fluid and the connecting direction of a signal electrode, the flow is detected by the signal electrode and enters a preamplifier circuit, the preamplifier circuit finishes impedance matching and differential amplification and then sends the amplified signal to a signal processing circuit, the signal processing circuit finishes signal conditioning and then sends the processed signal to a microprocessor circuit, the microprocessor circuit finishes flow calculation, and a display finishes flow display. The invention connects the signal electrode with the ground in the non-sampling period to release the polarization potential of the fluid, thereby eliminating the fatal defect of permanent magnet excitation and enabling the permanent magnet excitation to be applied to the electromagnetic water meter.)

1. A permanent magnet excitation method for an electromagnetic water meter is characterized in that:

1) two signal electrodes are respectively and symmetrically arranged on the inner wall of the pipeline, two permanent magnets are symmetrically arranged outside the pipeline, a working magnetic field is generated by the permanent magnets, and the connecting line direction of the working magnetic field is mutually orthogonal to the signal electrodes and the water flow direction; the grounding electrode is arranged on the inner wall of the pipeline and is connected with the ground; an input control signal S of the switch bridge is connected with a first output end of the microprocessor, signal ends X1 and X2 of the switch bridge are respectively connected with a signal electrode, and meanwhile, one input end Xd of the switch bridge is connected with a grounding electrode; the input signal of the preamplifier circuit is respectively connected with the output ends X1 'and X2' of the switch bridge; the input end of the signal processing circuit is connected with the output end of the preamplifier circuit, the output end of the signal processing circuit is connected with the input end of the microprocessor circuit, and the second output end of the microprocessor circuit is connected with the display;

2) signal ends X1 and X2 of the switch bridge in non-sampling time are connected with the grounding electrode through an Xd end of the switch bridge, so that the signal electrodes are conducted with the grounding electrode, and the two signal electrodes are connected with the ground through the grounding electrode;

3) the signal ends X1 and X2 of the switch bridge are respectively conducted with the signal ends X1 'and X2' of the switch bridge in sampling time, so that the two signal electrodes are respectively conducted with the first input end and the second input end of the preamplifier circuit, the connection between the signal electrodes and the grounding electrode is cut off, the flow signal is detected from the signal electrodes, and after the signal is processed by the preamplifier circuit and the signal processing circuit, the flow value is calculated by the microprocessor circuit and sent to the display for display.

2. A permanent magnet excitation method for an electromagnetic water meter as set forth in claim 1, wherein said switch bridge is adapted to control the connection and disconnection of the signal electrode to the ground electrode.

3. An electromagnetic water meter, characterized in that: the electromagnetic water meter comprises the permanent magnet excitation method for the electromagnetic water meter according to claim 1 or 2.

Technical Field

The invention relates to the technical field of electromagnetic water meters, in particular to a permanent magnet type excitation method for an electromagnetic water meter and the electromagnetic water meter.

Background

The working principle of the electromagnetic water meter is based on Faraday's law of electromagnetic induction. The necessary condition for maintaining the normal work of the electromagnetic water meter is a magnetic field with certain strength. At present, the magnetic field is generated in three ways: direct current excitation, power frequency sine wave excitation and rectangular wave excitation, except permanent magnet type direct current excitation, other excitation modes all need to provide current with certain intensity to ensure the intensity of a flow signal. The power consumption of the excitation module is a main component of the power consumption of the whole flow meter.

For the electromagnetic water meter powered by the battery, the excitation power consumption is reduced to the maximum extent, the service life of the battery is prolonged, and the essential requirements of the current technical development are met.

Disclosure of Invention

The invention aims to solve the defects in the prior art, and provides a permanent magnet excitation method for an electromagnetic water meter and the electromagnetic water meter thereof, so that the permanent magnet excitation method can be applied to the electromagnetic water meter.

In order to achieve the purpose, the invention provides the following technical scheme:

in a first aspect, the present invention provides a permanent magnet excitation method for an electromagnetic water meter, comprising:

1) two signal electrodes are respectively and symmetrically arranged on the inner wall of the pipeline, two permanent magnets are symmetrically arranged outside the pipeline, a working magnetic field is generated by the permanent magnets, and the connecting line direction of the working magnetic field is mutually orthogonal to the signal electrodes and the water flow direction; the grounding electrode is arranged on the inner wall of the pipeline and is connected with the ground; an input control signal S of the switch bridge is connected with a first output end of the microprocessor, signal ends X1 and X2 of the switch bridge are respectively connected with a signal electrode, and meanwhile, one input end Xd of the switch bridge is connected with a grounding electrode; the input signal of the preamplifier circuit is respectively connected with the output ends X1 'and X2' of the switch bridge; the input end of the signal processing circuit is connected with the output end of the preamplifier circuit, the output end of the signal processing circuit is connected with the input end of the microprocessor circuit, and the second output end of the microprocessor circuit is connected with the display;

2) signal ends X1 and X2 of the switch bridge in non-sampling time are connected with the grounding electrode through an Xd end of the switch bridge, so that the signal electrodes are conducted with the grounding electrode, and the two signal electrodes are connected with the ground through the grounding electrode;

3) the signal ends X1 and X2 of the switch bridge are respectively conducted with the signal ends X1 'and X2' of the switch bridge in sampling time, so that the two signal electrodes are respectively conducted with the first input end and the second input end of the preamplifier circuit, the connection between the signal electrodes and the grounding electrode is cut off, the flow signal is detected from the signal electrodes, and after the signal is processed by the preamplifier circuit and the signal processing circuit, the flow value is calculated by the microprocessor circuit and sent to the display for display.

Further, the switch bridge is used for controlling the connection and disconnection of the signal electrode and the grounding electrode.

In a second aspect, the present invention also provides an electromagnetic water meter comprising a permanent magnet excitation method for an electromagnetic water meter as claimed in claim 1 or 2.

Compared with the prior art, the invention has the beneficial effects that: the serious polarization phenomenon when the traditional direct current excitation is used for measuring the non-metallic fluid is eliminated by adopting a mode that a signal electrode is grounded to release the polarization potential in the non-sampling time, and the permanent magnet excitation in the sampling time avoids the electromagnetic field interference of the alternating current excitation.

The electromagnetic water meter adopting the method has a simple design structure, can effectively detect the flow signal under the condition of zero power consumption of the excitation module, can greatly reduce the power consumption of the electromagnetic water meter while ensuring the response speed of the meter, and prolongs the service life of a battery.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of the internal structure of the MOS transistor switch bridge circuit according to the present invention;

fig. 3 is a timing diagram of the microprocessor circuit controlling sampling and non-sampling during a single cycle time T.

Detailed Description

The present invention will now be described in more detail with reference to the accompanying drawings, in which the description of the invention is given by way of illustration and not of limitation. The various embodiments may be combined with each other to form other embodiments not shown in the following description.

In the description of the present invention, it should be noted that, for the terms of orientation, such as "central", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., it indicates that the orientation and positional relationship shown in the drawings are based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated without limiting the specific scope of protection of the present invention.

Furthermore, if the terms "first" and "second" are used for descriptive purposes only, they are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. Thus, a definition of "a first" or "a second" feature may explicitly or implicitly include one or more of the features, and in the description of the invention, "a number" means two or more unless explicitly defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "assembled", "connected", and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; or may be a mechanical connection; the two elements can be directly connected or connected through an intermediate medium, and the two elements can be communicated with each other. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.

As shown in figure 1, the invention provides a permanent magnet excitation method for an electromagnetic water meter, wherein two permanent magnets 1 are symmetrically arranged at two sides of a pipeline 2, and the polarities of the two permanent magnets are in the same direction. An aqueous fluid flows through the pipe 2, and an insulating layer is provided inside the pipe 2. The inner wall of the pipeline 2 is provided with a signal electrode 3 perpendicular to the diameter direction of the magnetic field, the inner wall of the pipeline 2 which is equidistant to the two signal electrodes is provided with a grounding electrode 4, and the electrodes 3 and 4 are insulated from the pipeline 2.

The input control signal S end of the switch bridge 5 is connected with the output end of the microprocessor circuit 8, and the signal end X1 of the switch bridge 5 is respectively connected with the two signal electrodes 3. Meanwhile, the other input terminal Xd of the switching bridge 5 is connected to the ground electrode 4.

The input signal of the preamplifier circuit 6 is connected to X1 'and X2' of the switch bridge 5, respectively. The input of the signal processing circuit 7 is connected to the output of the preamplifier circuit 6. The output of the signal processing circuit 7 is connected to an input of a microprocessor circuit 8.

The permanent magnet 1 generates a working magnetic field which is orthogonal to the flow velocity direction of water fluid and the connection direction of the signal electrode 3, a flow signal is detected by the electrode 3 and enters the preamplifier circuit 6, the preamplifier circuit 6 completes impedance matching and differential amplification, the obtained signal is sent to the signal processing circuit 7, the signal processing circuit 7 completes signal conditioning, the processed signal is finally sent to the microprocessor circuit 8, the microprocessor circuit 8 completes flow calculation, and a flow value is sent to the display 9 to complete flow display.

The detection of the conduction between the signal electrode 3 and the grounding electrode 4 and the detection of the flow signal are realized by the microprocessor circuit 8 through outputting a control signal S to control the switch bridge 5: during the non-sampling time, the microprocessor circuit 8 outputs a control signal S to enable X1, X2 and Xd of the switch bridge to form a passage, and a polarization potential generated on the signal electrode 3 due to the fact that the detected fluid is polarized by a direct current electric field is led into the ground through the conduction of the two electrodes 3 and the grounding electrode 4, so that the polarization of the electrode 3 is effectively removed; during the sampling time, the microprocessor circuit 8 outputs the control signal S to make the X1 and X1 ', and X2 and X2' of the switch bridge 5 form a path respectively, and the signal electrode and the ground electrode are disconnected to detect the flow signal.

The switch bridge 5 can adopt an integrated chip of 4 MOS tube switches, such as MPM3013 and the like, and can also be realized by discrete components; the preamplifier circuit 6 may employ a low drift, high common mode rejection ratio, high input impedance precision operational amplifier such as the operational amplifier ADA 4528.

In the schematic diagram of fig. 2, when the output voltage control signal S of the microprocessor circuit 8 is at a high level, G3 and G4 of the switch bridge 5 are turned on, and the signal electrode 3 is connected to the ground electrode 4; when the output voltage control signal S of the microprocessor circuit 8 is at a low level, G1 and G2 of the switch bridge 5 are turned on, and the detection of the flow rate signal is completed.

In the timing diagram shown in fig. 3, the electromagnetic water meter operates in such a manner that V + and V-alternate within a single cycle time T, and a flow signal is detected once at V-. The control signals for the switch bridge 5 are provided by a microprocessor circuit 8.

The invention also provides an electromagnetic water meter, which can effectively detect the flow signal under the condition of zero power consumption of the excitation module by adopting the permanent magnet excitation method, and can greatly reduce the power consumption of the electromagnetic water meter and prolong the service life of a battery while ensuring the response speed of the meter.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.