The principle of operation water meter

Water pipe on the water meter, the water meter dial are lined along the arc of several small pointer, the Central has a small red triangle, when the leading twist open water in the flow, this little red triangle on turning up. As for those little hands, regardless of water does not flow are almost motionless.
Scale disk is also written "m3" in the words, that the meaning of cubic water meters. That is, the table reading unit is cubic water meters. Because each cubic water meter of water happens to be a ton, reading tons of direct is the number, so water can easily by reading the total water use (tonnes) calculated.
water meter works then what is it? Actually very simple, because the water meter housing is fixed, its internal volume is fixed, while the water is flowing, it promotes a rotating impeller, the impeller when rotating circle, there is a constant volume of water flow through. Therefore, as long as the total number of turns the impeller rotation down, multiplied by the constant volume, we can get the total amount of water flowing through.
We have clear principles, and then to the inside of the concrete to see what kind of water meter it, because in order to prevent users from cheating, the lid of a type not allowed to open.
The internal structure of water water meters can be divided into the shell from the outside to inside, the sleeve, core Big Three. Housing is cast iron, water came out from the inlet through the lower part of the shell annular space, here called the "room under the ring." In the annular space above the "on the Central Room" and the outlet connected. The bottom of the sleeve has a filter with small holes, filter out the debris in the water. Sleeve up and down two rows of the side hole, the hole location just down the shell of the room facing the ring, obviously, the next row is a water hole, the row is a water hole. Of particular note is that both are along the row of holes round the tangent direction at an angle to play, its work as shown in animation. Note down two rows of holes in the opposite direction. Water from the next row of holes along the tangent direction of flow into the bound form a rotating flow, which the water meter is very important.
Letí»s look at the inner core, inner core is divided into upper, middle and lower-ranking, we see the upper windows, only the pointer and dial. In fact, the key is lower, and there are a plastic round, round the edge of many plastic blade, as shown above (Figure 1), called "impeller."
Impeller location right in the hole formed by the lower casing rotating flow, the current rush to round-week leaves to produce torque to spin the impeller. Leading to open the bigger, more rapid flow, the impeller to turn faster.

Impeller axis vertically upward to reach the middle, a little above the gear shaft, use it and the "decimal gear" gear, to transfer the cumulative number of purposes. "Decimal gear" role is to switch gears when the single digits 10 lap, 10-digit gear on a trip. In other words, a median turn ring gear, 10-digit is the ring gear on the turn. Gear is active by single digits, is sufficient to drive 10-digit gear. Virtually every one decimal complete with two pairs of gears to rotate in the same direction so that one pair of transmission ratio is 9: 30, another pair is 10.30, with two of the series, the overall transmission ratio is the Two of the product, that is 0.099999, can approximate 0.1.

On this basis, if you want to read seven-digit (decimal point before the time scale of four black, three red reading after the decimal point scale), you have to use the 12 pairs of gears. Together with a number of other purposes, in this small space to squeeze in the middle axis 18 and 34 gears, may be called high-density installation. I never thought, actually have a water table so much gear too!
Though we have entered the 21st century, but this mechanical water meter, with its simple and inexpensive, moist environment in long-term use without maintenance, and do not supply, power cuts will not affect the merits of the work will continue as our long-term service. Although electronic technology of water table there, but to spread to our homes of ordinary people also need a long time.