What's the structure of the valve before the water meter?
The valve is gate valve, the valve core and the dam gate principle is same, the gate heart rises, the water flows out the gate heart to be lower, the water is smaller, until closes!
Ball valve (valve core is a hole with the ball, when the hole with one side of the rotation to parallel with the body, that is, when left and right, there will be water outflow, when the side of the hole to go with the valve body vertical, that is close to the valve wall, there will be no water flow.
