Creativity knows no bounds, and instrumentation is a revolutionary invention. Today, we introduce a national invention patent—an ultrasonic flow sensor and its assembly method. This patent was applied for by Huizhong Instrument Co., Ltd., and was granted authorization on September 28, 2016.
Content Description
This invention relates to an ultrasonic flow sensor and its assembly method, particularly a flow meter that uses ultrasonic detection technology to measure the flow rate or heat of liquid in a pipeline, belonging to the fields of acoustics and sensing technology.
Background of the Invention
Currently, existing ultrasonic flow sensors, especially small-diameter ultrasonic flow sensors, typically rely on reflectors to transmit ultrasonic waves. These reflectors come in various forms, including sheet-like and cylindrical shapes. They are generally fixed by inserts or directly by the reflector itself fitting into the pipe section. For example, my patent application, "Measuring Pipe Section for Ultrasonic Flow and Calorimeter Converter with Beam Function," Chinese Patent No. ZL201020275319.2, uses an interference fit between the reflector and the pipe section for fixation. Other methods involve fixing the reflector by two longitudinally split halves, such as Chinese Patent No. 200810176267.0. Still others use cylindrical reflectors, fixed by matching circular holes on the pipe section. These ultrasonic flow sensors suffer from drawbacks such as high assembly precision requirements, numerous components, and complex structures.
Summary of the Invention
The purpose of this invention is to provide an ultrasonic flow sensor and its assembly method. The reflector is fixed in a simple way, the structure is simple, the assembly is convenient and quick, it is strong and reliable, and there are few components, thus solving the problems existing in the background technology.
The technical solution of the present invention is: an ultrasonic flow sensor, comprising a pipe section, a central sleeve, and a reflector, wherein the central sleeve is provided inside the pipe section, and the reflector is directly fixed on the central sleeve.
The figure is a schematic diagram of the structure of Embodiment 1 of the present invention.
In this invention, the pipe segment is provided with a pair of sensor mounting holes, each housing an ultrasonic sensor. The ultrasonic sensors are positioned within these mounting holes, and a central sleeve is positioned between the two ultrasonic sensors. The central sleeve has central sleeve fixing holes that match the sensor mounting holes, and the ultrasonic sensors are matched with reflectors. The central sleeve can be a complete tube with flush ends, its length exceeding the distance between the center lines of the pair of sensor mounting holes. A hole is formed in the wall of the central sleeve corresponding to the sensor mounting hole, and the reflector is fixed to the wall of the central sleeve corresponding to the sensor mounting hole. Alternatively, it can be an incomplete tube with at least one non-flush end, the wall of which extends to the position corresponding to the sensor mounting hole. The reflector is fixed to the wall of the central sleeve extending to the sensor mounting hole, and the length of the central sleeve, including its extended wall, is greater than the distance between the center lines of the pair of sensor mounting holes. The middle portion of the central sleeve has a reduced inner diameter, forming a measurement channel. Ultrasonic sensors are positioned on both sides of this reduced portion to improve measurement accuracy. The central sleeve is provided with an O-ring installation groove, and an O-ring is installed in the O-ring installation groove to seal between the pipe section and the central sleeve.
The central sleeve of this invention has two main functions: first, it provides a carrier for fixing the reflectors at both ends; second, it reduces the local flow area of the tube section, increasing the flow velocity of the measured medium passing through its channel and improving the measurement resolution of the instrument. The middle section is a fixed-length, reduced-length channel used to measure the flow velocity of the measured medium, generally located between two ultrasonic sensors or two reflectors. The length of the reduced section will not exceed the length between the outer contours of the closest distance between the two ultrasonic sensors or two reflectors; the cross-sectional area of the reduced section can vary with a constant area or a variable area.
The central sleeve is a one-piece structure, with the narrowed section in the middle integrally formed with both ends, making it a separate structure. It is divided into two or three sections radially along the central sleeve. The narrowed section in the middle is a single, indivisible unit, and the two or three sections are connected together by insertion, snap-fit, or other methods. Alternatively, the central sleeve can be divided into three sections: the narrowed section in the middle, the wall at the front end of the narrowed section, and the wall at the rear end of the narrowed section. Another option is to divide the central sleeve into two sections: the narrowed section and the wall at one end form one section, and the wall at the other end forms another section.
The central sleeve is fixed and positioned by an ultrasonic sensor mounted on the pipe section, or by other functional components and structural parts mounted on the pipe section, such as temperature sensors, fixing pins, clips, and threads. The reflector can be sheet-like or other shapes, such as a convex hemispherical shape. The reflector has clips on both sides, and the wall of the central sleeve has grooves that match the clips. The clips on both sides of the reflector are respectively engaged in the grooves on the central sleeve, thus fixing the reflector. The position and angle of the grooves on the central sleeve are determined according to the matching position and angle between the ultrasonic sensor and the reflector. The reflector can also be fixed to the central sleeve by other methods, such as bonding, welding, or injection molding inserts.
The beneficial effects of this invention are as follows: Because the reflector is directly assembled onto the central sleeve of the integrated structure, the entire flow sensor structure and assembly are simpler and more reliable, reducing production costs while significantly improving production efficiency. This invention features a simple and reasonable structure, convenient installation, high reliability, high measurement accuracy, and strong adaptability, and can be widely used in flow sensors for ultrasonic water meters, heat meters, and flow meters.
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