Single-lever mixers: ball or ceramic?
If you are used to washing your hands with soap and water, then you are probably a fan of single lever faucets. One single knob controls both the pressure and the temperature of the water. Simple, convenient, hygienic.
HOW DOES A VALVE DIFFERENT FROM A MIXER?
Usually we do not think about it and consider these words synonymous. Clarity is introduced by GOST 19681-94: A tap is a water-folding device that provides water from the water supply system and regulates its consumption by the consumer. The mixer, in addition to what a regular tap can do, also mixes cold and hot water, and also makes it possible to regulate its temperature.
CARTRIDGE: BALL OR CERAMIC?
You are deeply mistaken if you think that the filling of all single-lever mixers is the same. The cartridge inside can be ball or ceramic (consists of tightly ground ceramic plates). The ball is called so according to the shape of the main structural element – the regulating head, made of stainless steel. The hollow ball with holes and a pin is polished to a shine and tightly seated in the body, where hot and cold water is supplied from both sides through brass pipes or a flexible hose. Inside it, the two streams mix, and medium temperature water enters the spout. A handle is attached to the pin. When it is turned, the ball rotates. With a change in its position, the cross-sections of the holes for supplying cold and hot water change. To ensure tightness of the cartridge, the holes are sealed with gaskets. In addition, the ball cartridge has a ring that limits the angle of rotation of the handle towards hot water. This is done to prevent possible burns and makes it possible to “tune” the mixer for specific water supply conditions. The ceramic cartridge consists of two washers (plates) made of cermet, which are tightly ground to each other. As a rule, they are made from the so-called aluminum oxide. But the main thing is not even the material, but the processing. The cermet for branded mixers is sonicated and a pair of washers for each cartridge are perfectly matched to each other. Thanks to this surface treatment, interaction occurs between the plates at the molecular level – not a single drop of water can penetrate between them. By the way, you can check the quality of the disassembled cartridge by placing the washers on top of each other. If they are attracted, like magnetized, and it is not so easy to disengage them, then the cartridge will not leak. (We do not recommend doing such manipulations with a new cartridge on your own – in this case, manufacturers relinquish all warranty obligations.)
Just like in the ball regulating head, the plates have holes for supplying hot and cold water, the section of which changes when the handle is turned. Unlike ball cartridges, ceramic creators have managed to completely rid the structure of friction-prone gaskets – the most vulnerable element of the water mixing mechanism. (True, there are gaskets that seal the water inlet, but they do not experience those loads.)
Ceramic cartridges are also available with three plates (movable – medium). The design is specially designed for use in plumbing systems with low working pressure. In such models, water is mixed not in the “recess” between the plates, but in the valve body, which sharply reduces resistance and allows the mixer to be used even at 0.2 atm..
Of course, in the “advanced” ceramic cartridges, there are also temperature limiters for hot water, and all kinds of bells and whistles to save money.