THE BALANCE VALVE WATER METER.
THE balance valve water meter, here illustrated, is a single piston meter with three working parts—the piston and two valves. The cylinder and working parts are made of composition metal, and the heads of galvanized iron, any rust or corrosion within the apparatus being thus guarded against. For it the makers claim absolute noiselessness under any pressure, and accuracy in measurement under any and all flows, besides durability and cheapness.
This meter contains no springs or leather packing, liable to get out of repair, and is claimed to work equally well in clear, sandy or muddy water, any sediment or foreign substance being thrown out at each vibration of the piston, or lodged in pockets cast in the cylinder head and half-round valve case.
The cylinder or shell of the meter has simply a substantial, narrow bearing ring at each end, in which the piston, which is hollow and airtight, works. These rings occupy about one-third of the length of the inside of the cylinder, which is thus washed out at each stroke, the rest being cored out in the casting, and any sediment or sand running directly into pockets below, in the centre of the half-round valve case. The piston in its passage through the bearing rings is not bound in any manner, but is free to turn or roll, equal wear all around being thus insured.
The half-round valve case is the lower half of the meter and holds the half-round valve. Like the cylinder, it contains two bearing rings and has two pockets, as before said, for the reception of any sediment or grit. It also contains an exhaust port at each end and a seat in the centre for the B valve, with exhaust and inlet ports.
The B valve is an ordinary slide valve operated on its seat by the piston above in the main cylinder. The half-round valve consists of a casting half-round in shape with four inlet ana two exhaust ports. It works in the case, having a stroke only twice the width of the inlet ports, and is balanced in its case by an equal pressure on all sides.
The counting register is driven by a rocking shaft operated by the piston, on top of which and outside of the meter is attached a swiveled pawl, which operates a crown ratchet wheel above and connected with gearing on the crown register which moves the dial hands at each stroke. The object in placing the working parts of the escapement on the outside of the meter is to prevent the pawls from corroding or sticking.
The operation of the meter is as follows: In entering, the water passes down between the two plungers of the piston into the inlet port of the half-round valve (at the left of the cut), thence into the inlet port in the bottom of cylinder, and into the head of the meter. This starts the piston, which in its transit operates the B valve, opening a port into which the water flows, passing into the right lower half of the head and changing the half-round valve, which opens the inlet port of this valve at the right of the cut. The water now flows through this port carrying the piston back to the starting point and changing as it goes the B valve; this motion is kept up continually, the piston working the B valve, which opens a port to work half-round valve, and this in turn opens port to work the piston. The two wide ports in the half-round valve are exhaust ports, and are always open at either one end or the other, ». e., as the water is entering through the inlet port at one end cf the meter, it is being exhausted at the other through the wide port. The water which is used to change the half-round valve is exhausted into the middle port in the half-round valve case, and joins the main exhaust below.