A mechanical water meter is an instrument used to measure water flow and water consumption. Its internal structure can be divided into three parts from the outside to the inside: the shell, the sleeve, and the inner core.
The working principle of the mechanical water meter is as follows:
The water flow drives the impeller: the shell is fixed, and there is a certain volume space inside it. When the water flows, it flows into the sleeve from the lower hole of the water meter along the tangential direction to form a rotating water flow. This rotating water flow will drive the impeller in the inner core located at the lower hole position of the sleeve to rotate. There are many plastic blades on the edge of the impeller. The water flow impacts the blades to generate torque, which makes the impeller rotate. The speed of the impeller is proportional to the water flow, that is, the larger the faucet is opened, the faster the water flow is, and the faster the impeller rotates. For example, in daily life, when we fully open the faucet, the water flow is large and the impeller will rotate quickly; when we open the faucet very small and the water flow is small, the rotation speed of the impeller will slow down accordingly.
Counting mechanism measurement: There are counting mechanisms such as "decimal gears" in the water meter. Every time the single-digit gear rotates ten times, the tens-digit gear rotates one time. When the single-digit gear rotates one time, the tens-digit gear rotates one-tenth of a time, and so on to achieve multi-level counting. As the impeller rotates, these gears also gradually rotate, thereby converting the rotation of the impeller into corresponding digital changes, and then accumulating and counting the amount of water passing through the water meter. Since each circle of the impeller rotation represents a certain amount of water passing through, as long as the number of impeller rotations is accumulated and multiplied by the constant volume corresponding to each circle (this constant volume is determined by the design and manufacture of the water meter, and different water meters may have differences), the total amount of water flowing through can be obtained. For example, for a certain water meter, the volume of water corresponding to one circle of the impeller is 50 ml. If the impeller rotates 100 times, the total water consumption is 50 ml × 100 = 5000 ml, that is, 5 liters.
Various pulse signal metering forms:
Reed switch - magnet: add reed switch and magnet to the mechanical water meter, and use the reed of the reed switch to open and close cyclically under the action of the magnet, so as to output metering pulse signal. For example, when the impeller rotates, the magnet will rotate with the rotating parts. Every time it passes the position of the reed switch, the reed of the reed switch will open and close once, and then output a pulse signal, which is converted into the corresponding water volume value through the counting system.
Hall element - magnet: by adding Hall element and magnet, a sensor based on magnetoelectric conversion technology is formed. When the magnet installed on the counting disk rotates with the counting turntable, the Hall element will output a counting pulse every time it passes the Hall element. This is also a way to convert mechanical rotation into digital pulse signals for accurate water consumption.
Photoelectric conversion: install a photoelectric converter at the turntable of the water meter, and set a groove on the turntable. Every time the turntable rotates one circle, the groove will complete an electrical conversion when it passes the photoelectric converter, thereby outputting a counting pulse. This principle is also one of the ways to ensure that the water meter can accurately measure the water consumption.
Infrared sensor device: An infrared sensor device is installed at each position corresponding to the scale under the code disk of the mechanical water meter, and a data processor composed of a CPU and a single-chip microcomputer is installed inside the upper cover. The infrared sensor on each scale collects its scale display information to the processor and then runs the program to display the water meter data. This setting can accurately obtain the water meter reading through the infrared sensing and data processing system, while ensuring that a relatively accurate measurement result can be provided even in complex environments.
