Snifting valve

A poppet valve is a valve that opens at low pressure and can pass through air, until the negative pressure disappears. It has various applications in the automotive, pumps, turbines and plumbing.

Automotive

In the automotive sector, a poppet valve is a common up to the early 20th century form of valve control for four-stroke engines. In this case, the intake valve is not, for example via a cam, mechanically forced control. The valve is opened only over the sub- pressure created in the intake stroke in the combustion chamber. At the end of the intake stroke, it is closed by a spring again.

The disadvantage compared with mechanically operated valves is both a pressure loss because the incoming air must constantly keep the valve open against the spring force. On the other hand, the poppet for modern engines is not fixed rotational speed sufficient. This opens the valve sufficiently, the spring would have to be relatively weak, but then she can not close fast enough, the valve at a higher speed.

As a poppet valve and the Entlüftergummi of the oil filler neck is called the crankcase, this part has been installed at various Citroën, Peugeot and Renault models, including the Citroën 2CV ( " duck ").

Piston pump

Away from the automotive sniffing valves ( as for example in hydraulic ram ) used on piston pumps. For each stroke of a small amount of air is sucked through the blow valve. It serves as the attitude of the air cushion in the connected pressure vessels (air chamber, Hydrophore ).

Turbine

In direct flow for the generation of hydroelectric power, they are used to keep the water level below the rotor constant, so this is not wading in the water and would be slowed down by it.

Sanitary

Also used sniffer valves in plumbing, for example, if a washing machine and a normal sink use the same sewer. The blow valve is installed and prevents the expressed liquor of the washing machine entrains the water in the water trap according to the trap by the sink.