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CN-121994318-A - Flow detection device through runner gap

CN121994318ACN 121994318 ACN121994318 ACN 121994318ACN-121994318-A

Abstract

The invention provides a flow detection device passing through a gap of a rotating wheel, which comprises a shell flow channel, the rotating wheel and a rotating shaft/bearing assembly thereof, an optical window opposite to a blade area, a light source assembly and a light detection assembly which are arranged on the same side, a shading structure for blocking direct light and a extinction cavity corresponding to a gap light path, wherein a light detection signal is amplified and filtered, ambient light can be counteracted by adopting light source modulation and differential sampling, a pulse signal corresponding to the rotation of the rotating wheel is output by a comparison and shaping circuit with hysteresis for counting and converting flow, and a threshold value can be updated in a self-adaptive mode and amplitude abnormality diagnosis can be carried out. The invention improves the light intensity contrast ratio and the anti-interference capability of the blades and the gaps through the same side light source/receiving, shading structure, extinction cavity, amplifying shaping, and realizes the stable counting and reliable flow output of small flow without reflective marks.

Inventors

  • Sun Liecai
  • LIU XIAODONG
  • ZHOU JIFENG

Assignees

  • 深圳市睿联传感科技有限公司

Dates

Publication Date
20260508
Application Date
20260303

Claims (10)

  1. 1. A liquid flow sensing device for passing through a gap of a rotor, comprising: the shell is internally provided with a flow channel for liquid to flow through, and is provided with a water inlet and a water outlet; the runner is arranged in the runner and can rotate around a rotating shaft under the pushing of liquid, the rotating shaft is supported by a bearing, the runner is provided with a plurality of blades and gaps between adjacent blades, and the surfaces of the blades are not provided with independent reflectors/reflective marks; An optical window disposed on the housing opposite the blade region of the wheel; The light source assembly and the light detection assembly are arranged on the same side of the rotating wheel and are arranged towards the blade area of the rotating wheel through the optical window; The shading structure is arranged between the light source assembly and the light detection assembly and is used for blocking the light path of the light source assembly entering the light detection assembly directly and inhibiting stray light; The light extinction cavity is arranged in the transmission light path direction corresponding to the gap of the rotating wheel and is used for absorbing detection light passing through the gap, wherein the light extinction cavity is of a labyrinth type light trap structure and comprises at least two stages of foldback channels, the inner wall of the light extinction cavity is made of black extinction materials or blackened extinction surfaces so as to reduce reflection and return of light leakage of the gap, and the light shading structure is matched with the inlet position of the light extinction cavity, so that the receiving view field of the light detection assembly does not comprise the inlet direction of the light extinction cavity; The signal processing circuit is electrically connected with the light source assembly and the light detection assembly, and is used for driving the light source assembly to emit light in a preset modulation mode, performing synchronous sampling on the output of the light detection assembly to obtain a conducting sampling value and a cutting-off sampling value, then obtaining a difference signal to form a difference signal, amplifying, filtering and comparing and shaping the difference signal with hysteresis, and outputting a pulse signal related to the rotation of the rotating wheel for external counting to obtain flow; the pulse signal is generated by the difference light intensity change formed by the blade reflected light and the gap light leakage under the combined action of the shading structure and the extinction cavity; The hemispherical reflectivity of the inner wall of the extinction cavity in the wave band corresponding to the central wavelength of the light source assembly is not more than 10%, preferably not more than 5%, and/or the inner wall is coated with at least one of black matte coating, flocking coating and anodic oxidation blackening layer.
  2. 2. The liquid flow detection device according to claim 1, wherein rough texture treatment or microstructure extinction texture is provided on the inner wall of the return channel of the labyrinth type optical trap to improve light absorption efficiency and further suppress stray light return.
  3. 3. The liquid flow detection device according to claim 1, wherein the light shielding structure comprises a light emitting aperture/collimation structure arranged on the light emitting side of the light source assembly and a receiving light shielding cover arranged on the receiving side of the light detection assembly, and the light shielding ribs are arranged in the shell, so that no direct-view light path exists between the light source assembly and the light detection assembly; The receiving view angle of the light detection component is not more than 30 degrees, and the equivalent optical path of at least two stages of foldback channels of the labyrinth type optical trap is not less than 20mm, so that the transmitted light leakage passing through the gap is absorbed by multiple reflections after entering the extinction cavity and is difficult to return to the direction of the optical window.
  4. 4. The liquid flow rate detecting device according to claim 1, wherein the optical window is of an inclined surface or an arc surface structure, and a flow guide groove or a bubble discharge groove is arranged on a flow passage side close to the optical window for guiding bubbles away from a corresponding area of the optical window, and at least one of a hydrophobic/oleophobic coating or an anti-scaling coating is arranged on the surface of the optical window.
  5. 5. The liquid flow detection device according to claim 1, wherein a piezoelectric actuator is coupled to the housing or the optical window, and the piezoelectric actuator is electrically connected to the driving circuit, and is configured to output ultrasonic vibration under a preset trigger condition to perform bubble removal/decontamination self-cleaning on the optical window area, wherein the trigger condition at least includes that the cumulative pulse number reaches a threshold value, the running time reaches a threshold value, or the differential signal amplitude is lower than a preset amplitude threshold value.
  6. 6. The liquid flow detection device according to claim 1, wherein a transparent heating layer is arranged on the optical window, the transparent heating layer is electrically connected with a temperature sensor and/or a control circuit electrically connected with the humidity sensor, and the control circuit is used for controlling the heating of the transparent heating layer according to a dew point estimation result, so that the temperature of the optical window is kept higher than a preset margin of the dew point temperature, and light intensity drift caused by dew condensation is restrained.
  7. 7. The liquid flow detection device according to claim 1, wherein the light source assembly comprises at least two light emitting devices with different center wavelengths and alternately emits light in a time division manner, the signal processing circuit is used for respectively obtaining differential signals corresponding to different wavelengths and calculating a ratio or a difference value to form a pollution/turbidity indication quantity, and the comparison threshold value, the hysteresis quantity or the amplification gain is adaptively adjusted according to the indication quantity so as to improve the counting stability under the window pollution or medium turbidity change condition.
  8. 8. The liquid flow detection device according to claim 1, further comprising an energy collection module and a power management module, wherein the energy collection module is coupled to the rotating shaft or coupled to the shell vibration caused by fluid pulsation to generate electric energy, the power management module is used for rectifying and stabilizing the electric energy and supplying power to the light source assembly, the light detection assembly and the signal processing circuit, and is provided with an energy storage device, and the signal processing circuit is used for adaptively adjusting the light source modulation duty ratio and/or the sampling frequency according to the voltage state of the energy storage device to maintain stable pulse output.
  9. 9. The liquid flow rate detection device according to claim 1, further comprising a second detection channel, wherein the second detection channel is a second optical detection channel or a rotating wheel vibration detection channel, and the signal processing circuit is used for judging the pulse frequency or phase consistency of the first detection channel and the second detection channel, outputting the pulse signal when the consistency meets a preset condition, outputting a degradation pulse signal when the consistency does not meet the preset condition, and generating fault alarm information.
  10. 10. The liquid flow rate detection apparatus according to claim 1, wherein the signal processing circuit further includes a threshold adaptation and abnormality diagnosis unit for obtaining a peak value V_max and a valley value V_min of the differential signal and calculating a differential amplitude DeltaV=V_max in a statistical period And when the amplitude of the differential signal is continuously lower than the preset amplitude threshold, controlling to execute self-cleaning or anti-fog heating, and outputting a maintenance prompt or abnormal state signal when the amplitude is still lower than the preset amplitude threshold after execution.

Description

Flow detection device through runner gap Technical Field The invention relates to the technical field of detection equipment, in particular to a flow detection device through a gap of a rotating wheel. Background In the detection of the flow rate and the flow of a liquid pipeline in the scenes of household appliances, industry, water treatment, medical treatment and the like, the flow is calculated by outputting pulse signals and counting by a host computer. The existing scheme comprises the following steps: 1) Hall type flow meters typically utilize the change in voltage of a magnetic pole as the wheel rotates through a hall element to generate PWM pulses for counting, thereby scaling the flow. 2) The photoelectric flowmeter utilizes liquid to push the rotating wheel to rotate, realizes 'shielding/non-shielding' to cause the voltage change of the receiving end through a photoelectric reflection mode or a coded gear/shielding photoelectric pair tube (correlation/transmission), and forms PWM pulse counting to realize flow detection. The prior art has the following defects: 1) The problem of the structure and medium suitability of the Hall plus magnet scheme is that the Hall scheme needs to add a magnet on an impeller, so that the impeller is easy to be bigger and heavier, the moment of inertia is increased, the low flow response is poor, the metering precision is reduced, and meanwhile, the magnet and the assembly thereof can pollute the detected liquid or introduce adverse factors. 2) The technology and durability of the photoelectric + reflective mark/color punctuation scheme is that existing photoelectric schemes often implement detection by providing reflective areas or color punctuation on the wheel. The process links of the additional reflecting structure/mark are increased, and under the conditions of long-term water flow flushing, scaling, material aging and the like, the reflecting characteristics are easy to drift, so that the signal amplitude is unstable, the threshold value is difficult to keep consistent for a long time, and the risk of counting leakage or counting error occurs. 3) The problems of assembly and environmental sensitivity of the shielding/encoding gear photoelectric scheme are that the shielding type photoelectric pair tube often depends on stricter light path alignment and assembly tolerance, and in the pipeline working condition, factors such as scale, turbidity change, bubble attachment, condensation and the like can change light paths and light intensities to cause shielding edge shake, pulse burr or amplitude attenuation, and additional anti-interference and maintenance design is needed to ensure long-term stability. The problems of dew/bubble, window scaling and the like are typical interference sources affecting the stability of optical detection. 4) The small flow detection capability has a gap, namely, under the working condition of small flow, the rotating speed of the rotating wheel is low, the reflection/shielding change amplitude is small, the receiving end often shows a weaker analog signal (for example, the peak-to-peak value is only of a smaller magnitude), and the metering pulse can be stably formed by higher gain amplification, filtering and comparison shaping. 5) The pipeline liquid level sensor is mainly used for judging the state of 'liquid exists or not', and the detection mechanism and the output form of the pipeline liquid level sensor generally do not meet the requirement of flow/flow rate measurement on 'continuous pulse-count conversion', so that the pipeline liquid level sensor is difficult to directly replace a flowmeter. Accordingly, the prior art has shortcomings and needs further improvement. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides a flow detection device passing through a gap of a rotating wheel. In order to achieve the above object, the present invention is specifically as follows: the invention provides a liquid flow detection device passing through a runner gap, comprising: the shell is internally provided with a flow channel for liquid to flow through, and is provided with a water inlet and a water outlet; the runner is arranged in the runner and can rotate around a rotating shaft under the pushing of liquid, the rotating shaft is supported by a bearing, the runner is provided with a plurality of blades and gaps between adjacent blades, and the surfaces of the blades are not provided with independent reflectors/reflective marks; An optical window disposed on the housing opposite the blade region of the wheel; The light source assembly and the light detection assembly are arranged on the same side of the rotating wheel and are arranged towards the blade area of the rotating wheel through the optical window; The shading structure is arranged between the light source assembly and the light detection assembly and is used for blocking the light path of the light source assembly entering the lig