Schrader: Manufacturer of tyre valves, pressure to perfection

Valve cores,
the valve core equipped with its check valve for inflation and pressure measurement.

The bridge for screwing the valve core into its housing.
The seat with its joint providing a static seal from the valve body.
The valve with its spring for introducing or draining fluid and guaranteeing sealing under pressure in the rest position.

Some examples of materials and finishes:
Materials: Brass, stainless steel, elastomer
Joint: Polychloroprene, Nitrile-butadine, Hydrogenated nitrile-butadine, Fluorocarbon, EDPM
Body finish: Rough, Enamelled, Enamelled copper plate

Some examples of applications by model:
Air, nitrogen, R12, R22, R134a, oils, Halon, SF6, Petrols, butane, propane..

VALVE CORES ARE DEFINED BY THEIR CHARACTERISTICS
and, depending on the type selected, these characteristics vary, depending on the material, the finish and the design of each valve core.

Detachment pressure:
This is the air pressure necessary to overcome the resistance of the spring that keeps the valve closed, allowing air to pass through.
Opening pressure:
This is the pressure necessary to open the valve significantly, causing a significant debit to pass through the valve core.
Debit :
It is measured in the direction of the air loss under a pressure of 7 bars, the valve being open to the max. The air is then put back under normal conditions.
Min. travel:
This is the valve opening travel necessary to allow the min. air debit necessary for a pressure measurement, for example.
Max. travel:
(valid only for short valve cores with spring above the bridge). This is the valve opening travel not to be exceeded to avoid damaging the valve core’s spring.
Working pressure:
This is the pressure under which the valve core’s check valve can operate without damage being done to it. In static this pressure can be significantly higher.
Tightening torque:
This is the tightening torque which must be applied to the valve core to achieve sealing.