Direct-reading water meter without outgoing line

Abstract

The utility model relates to the technical field of water meters, in particular to a direct-reading water meter without an outgoing line, which comprises a direct-reading water meter head, a near-field induction winding is added on the direct-reading water meter head, and the near-field induction winding is communicated with a direct-reading driving circuit PCB (printed circuit board) in a direct-reading circuit cavity through a lead groove in the near-field induction winding. A near-field power supply soft start circuit is arranged in the direct-reading drive circuit PCB and used for starting a water meter direct-reading circuit, and an external near-field main control winding is installed outside the water meter glass cover. The direct-reading water meter overcomes the problem that a wire needs to be led out of a water meter shell of a traditional direct-reading water meter, avoids the defect that the mechanical structure of the water meter shell needs to be greatly changed in the production process, fundamentally avoids faults caused by the fact that the led-out wire is broken, has the advantages of being low in cost and high in reliability, and is suitable for popularization and application. And the intelligent water meter has very important promotion significance on the development of water meter intelligence.

Description

Technical Field

[0001] The utility model relates to the technical field of water meters, in particular to a direct-reading water meter without lead wires. Background Art

[0002] Direct-reading water meters are widely welcomed in the industry for their advantages such as accurate electromechanical conversion and almost no energy consumption. With the advancement of technology, the technical field of direct-reading water meters and gas meters has gradually broken the constraints of the original photoelectric conversion of "photoelectric direct reading". In recent years, a new type of non-magnetic induction direct reading has emerged in China, which overcomes the shortcomings of photoelectric direct reading: low angular resolution, easy damage, high cost, susceptibility to ambient light interference, and poor anti-pollution ability. It has gradually become the most watched method for converting mechanical signals of mechanical instruments into electrical signals.

[0003] However, both photoelectric direct-reading water meters and non-magnetic induction direct-reading water meters have a serious disadvantage: a power supply and communication composite line (lead-out wire) needs to be led out from the inside of the water meter housing. The lead-out wire of the direct-reading water meter not only affects the mechanical structure of the original housing of the water meter, causing inconvenience and cost increase in production, but also is easy to be damaged. Therefore, the lead-out wire of the direct-reading water meter has been a problem that has plagued the industry for a long time.

[0004] To this end, the present application designs a direct-reading water meter without lead wires, which adopts near-field wireless coupling to solve the two problems of power supply of the direct-reading module inside the water meter and transmission of the direct-reading information to the outside. Utility Model Content

[0005] In order to make up for the deficiencies in the prior art, the utility model provides a direct-reading water meter without lead wires.

[0006] The utility model is realized through the following technical solutions:

[0007] A direct-reading water meter without lead wires, comprising a direct-reading water meter head, characterized in that:

[0008] A near-field induction winding is added to the head of the direct-reading water meter. The near-field induction winding is connected to a direct-reading drive circuit PCB board in the direct-reading circuit cavity through an internal lead groove of the near-field induction winding. A near-field power supply soft-start circuit is provided in the direct-reading drive circuit PCB board to start the water meter direct-reading circuit. An external near-field main control winding is installed outside the water meter glass cover.

[0009] Furthermore, in order to better realize the utility model, a boss is installed in the pointer wheel display area of ​​the direct-reading water meter head as a near-field induction winding cavity, a near-field induction winding is placed in the near-field induction winding cavity, and a semi-circular near-field induction winding internal lead groove is opened on the outer circle of the water meter glass cover sealing ring groove of the direct-reading water meter head, and the near-field induction winding internal lead groove connects the near-field induction winding cavity and the direct-reading circuit cavity.

[0010] Furthermore, in order to better realize the utility model, the near-field induction winding is wound with nylon-coated waterproof enameled wire, and sealant is poured in the near-field induction winding cavity and the direct-reading circuit cavity.

[0011] Furthermore, in order to better implement the present invention, the external near-field main control winding is installed at a position close to the near-field induction winding, and electromagnetic coupling is formed between the external near-field main control winding and the near-field induction winding.

[0012] Furthermore, in order to better realize the utility model, the external near-field main control winding is excited, and the excitation adopts a high-frequency AC source with a frequency of 2Mhz; the external near-field main control winding and the near-field induction winding both adopt a self-inductance of 21uH, and the resonant capacitor adopts 300P.

[0013] Furthermore, in order to better realize the utility model, the purpose of the near-field power supply soft start circuit is to prevent the inability to start the direct reading circuit inside the water meter due to the near-field coupling efficiency being too low. The circuit uses a larger energy storage capacitor E1 to first store the relatively weak induced electric energy on the energy storage capacitor, and then suddenly turns on the LDO to supply power to the water meter direct reading circuit after the voltage of the energy storage capacitor is high enough.

[0014] When the LDO is not turned on, since a high input impedance field effect transistor is used as a soft-start acceleration switch and the LDO is in a low power consumption state, the resonant circuit composed of the near-field induction winding and the resonant capacitor has a high Q value. Even a very small mutual inductance coupling will accumulate sufficient voltage on E1.

[0015] Furthermore, in order to better realize the utility model, when receiving external data, the lead-free direct-reading water meter first needs to use the near-field main control winding to power the water meter through high-frequency excitation, and then send data to the water meter through ASK keying modulation. The digital coding method used is pulse width coding.

[0016] Furthermore, in order to better implement the present utility model, the leadless direct-reading water meter adopts a proportional pulse width encoding method when sending data to the outside, specifically:

[0017] The returned data starts with absorbing the carrier. The absorption and non-absorption of equal pulse width is regarded as a bit. The absorption and non-absorption pulse width = 80uS:80uS is bit1, and the absorption and non-absorption pulse width = 50uS:50uS is bit0. The absorption and non-absorption refers to absorbing more carrier energy through R1. When N2 is turned on, the access of R1 will cause L3 to absorb more excitation signal energy from L1. During the period when the water meter sends data to the outside, the controller outside the water meter needs to continuously provide excitation signal to L1. The external control circuit needs to determine whether L1 absorbs more energy and demodulate the data sent by the water meter. The advantage of the encoding method for sending data to the outside by the water meter is that the average value = 0, so there is no DC component, and a very high AC amplifier can be used to amplify the weak signal demodulated after impedance modulation.

[0018] Furthermore, in order to better implement the present utility model, the process of the direct-reading water meter without lead wires communicating with the outside is as follows:

[0019] S1, carrier activation, first the master controller sends an activation carrier through the external near-field master control winding, the duration is 10mS-1500mS, which needs to be determined according to the distance and overlap between the external near-field master control winding and the near-field induction winding inside the water meter;

[0020] S2, after sending the instruction, the carrier activates the water meter. If the carrier continues to be sent, the water meter will return the data after a 5mS delay after the power soft start is completed; if the carrier is intermittent and exceeds 20uS, the water meter believes that the master end wants to send data to the water meter, and the water meter cancels the automatic completion of direct reading and data return process, and enters the master control data receiving process instead;

[0021] S3, the water meter sends back data. The water meter will upload data in two cases: first, there is no carrier interruption after the master control activates the water meter. After the water meter completes the power soft start, it delays for 5mS and automatically uploads data. Second, the master control sends a carrier interruption after activating the water meter, and then sends data to the water meter. The water meter responds to the master control data before answering.

[0022] The beneficial effects of the utility model are:

[0023] The utility model is a non-leading direct-reading water meter that uses near-field radio to achieve energy coupling and communication inside and outside the water meter housing. Energy is provided to the inside of the water meter through wireless near-field induction, and internal and external communication is achieved through inductive coupling. Therefore, it is possible to completely avoid leading wires from the water meter housing. The advantages are:

[0024] First, it can significantly reduce costs;

[0025] Second, it can significantly improve product quality by avoiding water meter damage caused by lead damage;

[0026] Third, it avoids the wiring coupling between the water meter base meter and the intelligent components, which greatly facilitates the water meter calibration and on-site maintenance;

[0027] Fourth, direct reading realizes the conversion of mechanical signal into electrical signal of water meter, and its advantages are: accuracy, especially the non-magnetic induction direct reading of domestic utility models in recent years, which is not only accurate but also low-cost. However, it is limited by the need to lead wires from the water meter shell, which has brought resistance to the widespread use of non-magnetic induction direct reading. The utility model paves the way for direct reading water meters in intelligent applications, which is of great significance to the intelligentization of water meters in my country. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the three-dimensional structure of the direct-reading water meter head of the utility model;

[0029] Figure 2 The second is a three-dimensional structural schematic diagram of the direct-reading water meter head of the utility model;

[0030] Figure 3 It is a schematic diagram of the top view of the structure of the direct-reading water meter head of the utility model;

[0031] Figure 4 The figure is a schematic diagram of the upward structure of the direct-reading water meter head of the utility model;

[0032] Figure 5 It is a longitudinal cross-sectional view of the direct-reading water meter without lead wires of the utility model;

[0033] Figure 6 It is the near-field power supply soft start circuit of the utility model;

[0034] Figure 7 This is a PCM encoding method diagram of the utility model;

[0035] Figure 8 This is a diagram of the proportional pulse width encoding method of the utility model.

[0036] In the figure,

[0037] 1. Direct-reading water meter head, 2. Character wheel cavity, 3. Pointer wheel display area, 4. Near-field induction winding cavity, 5. Near-field induction winding, 6. Water meter glass cover sealing ring groove, 7. Near-field induction winding internal lead groove, 8. Near-field induction winding outlet, 9. Direct-reading circuit lead outlet, 10. Direct-reading circuit cavity, 11. Direct-reading drive circuit PCB board, 12. Near-field induction winding leads, 13. External near-field main control winding, 14. Water meter bell, 15. Water meter glass cover. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the utility model provided in the accompanying drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents selected embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0040] Figure 1-Figure 8 This is a specific embodiment of the utility model, which is a lead-free direct-reading water meter. There are many methods for realizing direct reading of water meters at present, but the traditional direct-reading methods all require a power supply and communication composite line to be drawn out from the water meter housing. This lead line will not only cause major mechanical changes to the water meter housing, but also the wires at the outlet are easily damaged by scratches caused by the water meter bell when it is tightened. At the same time, with the development of intelligent water meters, the intelligent components of water meters need to obtain data from the water meter base meter, and the traditional direct-reading water meter needs to draw wires from the inside of the water meter housing, which will cause the water meter intelligent components and the water meter base meter to form a tight coupling, which will bring great disadvantages to the water meter calibration.

[0041] This embodiment improves the traditional direct-reading water meter by adding: a near-field sensing winding cavity and a near-field sensing winding lead groove, the near-field sensing winding is embedded in the near-field sensing winding cavity, and the lead of the near-field sensing winding is embedded in the near-field sensing winding lead groove, and the lead is connected to the direct-reading circuit cavity along the groove. The near-field sensing winding cavity and the near-field sensing winding lead groove are both potted with potting glue, and the near-field sensing winding preferably uses nylon-coated waterproof enameled wire, thereby achieving the purpose of not requiring external leads for the direct-reading water meter. In order to read the data of the direct-reading water meter from the outside of the water meter, it is necessary to install an external near-field main control winding for reading outside the water meter glass cover, covering the position of the near-field sensing winding inside the water meter as much as possible in space, so that the two internal and external windings achieve: energy coupling and data coupling through mutual inductance.

[0042] First of all, in order to achieve direct reading, the water meter direct reading circuit requires energy. To solve this problem, this embodiment requires an external near-field main control winding to provide excitation, using high-frequency AC excitation. According to the law of electromagnetic induction, the magnetic flux of the two coils overlap, thus forming a mutual inductance relationship. The external excitation energy can be received by the internal winding of the water meter and DC is obtained after rectification.

[0043] Secondly, in order to ensure that the water meter direct reading circuit can be started smoothly, this embodiment designs a direct reading water meter near-field induction power soft start circuit, which can ensure that the internal direct reading circuit can be started smoothly under weak power, thereby improving reliability.

[0044] Again, this embodiment defines the inductance of the inner and outer windings of the water meter and the parameters of the matching resonant capacitor, and also makes clear provisions for the operating frequency, thus making preparations for product standardization.

[0045] Finally, this embodiment defines the external meter reading process of the leadless direct-reading water meter using near field communication, as well as the communication modulation method and encoding rules, so as to ensure good feasibility and compatibility.

[0046] like Figure 1-Figure 5 As shown, compared with the traditional direct-reading water meter head, this embodiment adds a near-field induction winding cavity in the pointer wheel display area of ​​the meter head, and the near-field induction winding (receiving winding) is installed in this cavity. The near-field induction winding is preferably wound with nylon-coated waterproof enameled wire. After the winding is embedded in the near-field induction winding cavity, it is necessary to fill the near-field induction winding cavity with sealant to isolate the external water environment. The internal lead groove of the near-field induction winding is opened outside the groove of the sealing ring of the water meter glass cover. The lead of the near-field induction winding is inserted from the "near-field induction winding outlet" into the internal lead groove of the near-field induction winding, around half of the outer circle of the direct-reading water meter head to reach the direct-reading circuit outlet, and the lead is inserted into the direct-reading circuit cavity and welded to the direct-reading circuit PCB. The internal lead groove of the near-field induction winding needs to be filled with a potting glue to play a role in sealing and waterproofing. At the same time, it is preferred to use nylon-coated waterproof enameled wire to further improve the waterproof ability.

[0047] After the final assembly of this embodiment is completed, no lead wires are led out of the water meter housing. The direct-reading water meter without lead wires obtains energy from the outside of the water meter glass cover through a near-field induction coil to achieve direct reading. The near-field induction coil is also used to achieve data exchange with the outside.

[0048] like Figure 5As shown, when the external part needs to read the direct-reading water meter data, an external near-field master winding needs to be installed above the water meter glass cover and at the position covered by the near-field induction winding inside the water meter to form an electromagnetic coupling between the two. According to the law of electromagnetic induction, the magnetic flux of two coils that are close to each other in space will be coupled, forming a mutual induction relationship, and the degree of coupling can be measured by the mutual inductance coefficient. In order to provide the energy required for direct reading inside the water meter, the near-field master coil outside the water meter is required to be excited, which is called excitation. The excitation uses a high-frequency AC source. In order to be more standardized, the preferred frequency of the excitation signal in this embodiment is: 2Mhz, and the external near-field master winding and the near-field induction coil both use 21uH self-inductance, and the resonant capacitor uses 300P. This is the preferred value, which is a parameter defined for more standardization. Of course, other parameters can also be used, but there will be no better effect, which will only lead to inconsistent technical standards in the industry and cause compatibility difficulties. It cannot be used as an excuse to bypass the utility model.

[0049] like Figure 6 As shown, due to the uncertainty of the distance between the two coils involved in near-field induction, the coupling efficiency between the two coils will vary greatly. If the coupling efficiency is low, the power obtained by the near-field induction winding inside the water meter is very small, which may not be enough to start the water meter direct reading circuit. To solve this problem, this embodiment adopts a water meter direct reading circuit near-field power supply soft start circuit. As shown in the circuit diagram, L1 is an external main control winding, C3 is a resonant capacitor, and C3L1 constitutes a series resonant circuit. L3 is a near-field induction winding inside the water meter, C4 is a resonant capacitor, and C4L3 constitutes a parallel resonant circuit. U2 is a full-bridge rectifier device. The excitation signal of L1 sensed by L3 obtains the maximum amplitude through resonance. E1 is an energy storage capacitor. U3 is a DO device with Enable. When EN=0, U3 is in a low-power state, and the output = 0V. P1 is a P-channel field effect transistor, and N1 is an N-channel field effect transistor. When the voltage of E1 is lower than the breakdown voltage of Z1, R13 has no current, so the voltage across the two ends is 0. When E1 is higher than the breakdown voltage of Z1, R13 has current, and the voltage across R13 is not 0. When the voltage across R13 is sufficient to turn on P1, P1 turns on, provides current to R12, turns on N1, and N1 short-circuits Z1 to further turn on P1 to form positive feedback, accelerating the conduction of P1. R12 provides the EN signal of U3 to turn on LDO. Since the capacity of E1 is large, the stored electric energy is sufficient to start the direct reading circuit and support the completion of direct reading.

[0050] In order to prevent the inability to start the direct reading circuit inside the water meter due to the low near-field coupling efficiency, this embodiment specially designs a near-field power supply soft start circuit for the water meter direct reading circuit. The circuit uses a larger energy storage capacitor E1 to first store the relatively weak inductive electric energy on the energy storage capacitor, and then suddenly turns on the LDO to supply power to the water meter direct reading circuit after the voltage of the energy storage capacitor is high enough. In the LDO non-starting stage, since a high input impedance field effect tube is used as a soft start acceleration switch, and the LDO is in a low power consumption state, the resonant circuit composed of the near-field induction winding and the resonant capacitor has a high Q value, and even if the mutual inductance coupling is very small, sufficient voltage will be accumulated on E1.

[0051] The above circuit is only an implementation example of the near-field power supply soft start circuit of the leadless direct-reading water meter direct-reading circuit. In order to realize the leadless direct-reading water meter, this application needs to adopt power supply soft start in the near-field induction power supply. There are many methods that can be implemented, all of which are within the scope of the claims of this utility model.

[0052] In order to realize the near-field power supply soft start of the water meter internal circuit, the near-field main control winding is required to first perform an activation cycle of the water meter. This cycle is used for the near-field power supply soft start circuit of the water meter direct reading circuit to charge the energy storage capacitor. Calculated by the energy storage capacitor 220uF storing energy to 6V and the charging current 1mA, the charging time is about: 1.32S.

[0053] If the reading device outside the water meter wants to read the data of the leadless direct-reading water meter involved in this embodiment, it first needs to use the near-field main control winding to power the water meter through high-frequency excitation, and then send data to the water meter through ASK keying modulation. The digital encoding method used is: pulse width coding (PCM), such as Figure 7 As shown, this embodiment preferably adopts the following encoding method: idle width = 30uS, Bit0 carrier width = 50uS, Bit1 carrier width = 80uS.

[0054] C1, R3, R4 and C2 form a π-type filter, which can recover the binary data from the ASK keying modulation, and then provide it to the water meter direct reading processing microcontroller after level conversion, and the microcontroller completes the decoding work.

[0055] The water meter uses load impedance modulation to send data to the outside. Figure 6 R1, N2, when TX is BIT1, N2 is driven to conduct, R1 becomes the load of U2 output, because R1 is small, it will cause L3 to absorb L1's power significantly increased, the near field communication slave uses load impedance modulation to achieve reverse data transmission, which is a common method of near field communication and is not within the scope of this application. However, the reverse data communication encoding method used in this application is not available in the prior art, specifically:

[0056] The returned data starts with absorbing the carrier. The absorption and non-absorption of proportional pulse width is regarded as a bit. The absorption and non-absorption pulse width = 80uS:80uS is bit1, and the absorption and non-absorption pulse width = 50uS is bit0 (such as Figure 8 As shown); the so-called "absorption" and "non-absorption" refer to whether more carrier energy is absorbed through R1. When N2 is turned on, the connection of R1 will cause L3 to absorb more excitation signal (carrier) energy from L1. During the period when the water meter sends data to the outside, the controller outside the water meter needs to continuously provide an excitation signal (carrier) to L1, and the external control circuit needs to determine whether more energy is absorbed by L1 and demodulate the data sent by the water meter. The encoding method for sending data to the outside by the water meter involved in this embodiment has the following advantages: the average value = 0, so there is no DC component, and a very high-multiple AC amplifier can be used to amplify the weak signal demodulated after impedance modulation.

[0057] The process of externally reading water meter data is as follows:

[0058] a) Carrier Activation

[0059] First, the master controller sends an activation carrier through the near-field master control winding, with a duration of 10mS-1500mS, which depends on the distance and overlap (mutual inductance coefficient) between the near-field master control winding and the near-field sensing winding inside the water meter. In intelligent water meter applications, such as Nbiot water meters and Cat1 water meters, the external near-field master control winding is only 8-15mm away from the near-field sensing winding inside the water meter, and they overlap in space. Therefore, the coupling degree of the two windings is relatively high, and the carrier activation time only needs 10mS.

[0060] b) Issue instructions

[0061] After the carrier activates the water meter, if the carrier continues to be sent (without interruption), the water meter will return data after a delay of about 5mS after the power soft start is completed. If the carrier is interrupted and exceeds 20uS, the water meter believes that the master end wants to send data to the water meter, and the water meter cancels the automatic completion of direct reading and data return process, and enters the master data receiving process instead.

[0062] The first gap in the carrier is called the data transmission synchronization gap, or synchronization gap for short.

[0063] After the Gap is synchronized, the master sends data starting from the carrier. 50uS carrier + 30uS Gap represents Bit0, and 80uS carrier + 30uS Gap represents Bit1. 8 bits are a byte. After the data is sent (the last Gap), the carrier continues to be provided.

[0064] c) Water meter feedback data

[0065] The water meter will upload data in two cases: First, there is no carrier interruption after the master control activates the water meter. After the water meter completes the power soft start, it delays about 5mS and automatically uploads data. Second, the master control activates the water meter and sends a carrier interruption, then sends data to the water meter. The water meter responds to the master control data before answering.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.

Claims

1. A direct-reading water meter without lead wires, comprising a direct-reading water meter head (1), characterized in that: A near-field induction winding (5) is added to the direct-reading water meter head (1); the near-field induction winding (5) is connected to a direct-reading drive circuit PCB board (11) in a direct-reading circuit cavity (10) through an internal lead groove (7) of the near-field induction winding; a near-field power supply soft start circuit is provided in the direct-reading drive circuit PCB board (11) for starting the water meter direct-reading circuit; and an external near-field main control winding (13) is installed outside the water meter glass cover (15).

2. The direct-reading water meter without lead wire according to claim 1 is characterized in that: A boss is installed in the pointer wheel display area (3) of the direct-reading water meter head (1) as a near-field induction winding cavity (4), a near-field induction winding (5) is placed in the near-field induction winding cavity (4), a semicircular near-field induction winding internal lead groove (7) is opened on the outer ring of the water meter glass cover sealing ring groove (6) of the direct-reading water meter head (1), and the near-field induction winding internal lead groove (7) connects the near-field induction winding cavity (4) and the direct-reading circuit cavity (10).

3. The direct-reading water meter without lead wires according to claim 2 is characterized in that: The near-field induction winding (5) is wound with nylon-coated waterproof enameled wire, and sealant is poured into the near-field induction winding cavity (4) and the direct-reading circuit cavity (10).

4. The direct-reading water meter without lead wires according to claim 1 is characterized in that: The external near-field main control winding (13) is installed at a position close to the near-field induction winding (5), and electromagnetic coupling is formed between the external near-field main control winding (13) and the near-field induction winding (5).

5. The direct-reading water meter without lead wires according to claim 4 is characterized in that: The external near-field main control winding (13) is excited, and the excitation adopts a high-frequency AC source with a frequency of 2Mhz; the external near-field main control winding (13) and the near-field induction winding (5) both adopt a self-inductance of 21uH, and a resonant capacitor adopts 300P.

6. The direct-reading water meter without lead wires according to claim 1 is characterized in that: The purpose of the near-field power supply soft start circuit is to prevent the inability to start the direct reading circuit inside the water meter due to the near-field coupling efficiency being too low. The circuit uses a larger energy storage capacitor E1 to first store the relatively weak induced electric energy on the energy storage capacitor, and then suddenly turns on the LDO to supply power to the water meter direct reading circuit after the voltage of the energy storage capacitor is high enough. When the LDO is not turned on, since a high input impedance field effect transistor is used as a soft start acceleration switch, and the LDO is in a low power consumption state, the resonant circuit composed of the near-field induction winding and the resonant capacitor has a very high Q value, and even if the mutual inductance coupling is very small, sufficient voltage will be accumulated on E1.

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