Water meter is an instrument for measuring water flow, mostly the cumulative flow of water. Generally divided into two types: volumetric water meter and speed water meter. It originated in Britain and has a history of nearly 200 years. When choosing the specifications of water meters, we should first estimate the size and range of the flow used under normal circumstances, and then choose the most common flow as the first choice.
structure
The internal structure of traditional water meter can be divided into three parts: shell, sleeve and inner core from outside to inside. The shell is made of pig iron, and the water passes through the lower annular space of the shell after coming out of the water inlet, which is called the "lower annular chamber" here. Above this annular space, there is an "upper ring chamber" communicating with the water outlet. There is a filter screen with small holes at the bottom of the sleeve to filter out impurities in water.
There are upper and lower rows of circular holes on the side of the sleeve, and the positions of the holes are opposite to the upper and lower annular cavities of the shell. Obviously, the lower row is the water inlet hole and the upper row is the water outlet hole. It is particularly noteworthy that these two rows of holes are made obliquely along the tangent direction of the circle. Note that the upper and lower rows of holes are in opposite directions. The tangential inflow of water from the lower drainage hole is bound to form a rotating water flow, which is very important for the work of the water meter.
The inner core is divided into upper, middle and lower layers. From the glass window, you can see the upper layer, only the pointer and dial. In fact, the most important thing is the lower level. There is a plastic wheel inside, and there are many plastic blades on the edge of the wheel, which is called "impeller".