The Schrader valve (also called American valve ) is a type of pneumatic tire valve used in almost every motor vehicle in the world today. The Schrader company, named after it, was founded in 1844 by August Schrader. The original Schrader valve design was created in 1891, and patented in the United States in 1893.
The Schrader valve consists of a valve stem in which the thread core is threaded, and is used on almost all the tires of motor cars and motorcycle tires and the most wide-framed bicycle tires. The valve core is a helmet valve aided by a spring.
Video Schrader valve
Usage
In addition to tubeless and tubeless tires, Schrader valves with varying diameters are used in many cooling and air conditioning systems to enable service, including refilling with refrigerant; by a plumber conducting a leak-pressure test into a pipe installation; as bleeding and test ports on the fuel rails of some fuel injection engines; on air bicycle shock absorbers to allow adjustment of air pressure according to the weight of the rider; and in the buoyancy compensator (BC) SCUBA system inflators where the ability to easily disconnect air hose (even under water) without losing air tank is essential. Schrader valves are also widely used in high-pressure hydraulic systems on aircraft. Many domestic firefighters use an internal valve that is identical to the Schrader valve, but with leverage on it to allow rapid discharge of the pressurized content.
Maps Schrader valve
Valve
The Schrader valve consists of an external cylindrical cylindrical metal tube, usually of a nickel-plated brass. At the center of the exterior end is a metal pin pointing along the valve stem axis; the end of the pin is approximately flat with the tip of the valve body.
All Schrader valves used on tires have threads and bodies of a single standard size at the outer end, so hats and tools are generally universal for valves in all common applications. The core of the valve can be removed or tightened with the tool.
Industrial Schrader valves are available in different diameter and valve core variants and are used in refrigeration, propane, and various other uses.
The new development is a Schrader valve rod with integrated transmitter for tire pressure monitoring system (TPMS).
Cap
Close the valve is important on the Schrader valve because if not installed, dirt and water can enter the inside of the valve stem, potentially disturbing or contaminating the sealing surface and causing leakage.
Metals, and some hard plastic valve caps have a rubber-washer seal (or rubber-rubber-washer) seal inside to help make airtight seal (airtight seals). Cover helps prevent air from leaking out of the valve. In addition, the rubber washer prevents the hat from loosening and falls due to vibration and is therefore lost, acting as a cushion between the lid and the valve stem and in this way dampening vibrations, although most hats are a softer plastic manufacture. the need for a separate seal is not necessary.
Schrader versus other valve types
While Schrader's valves are almost universal on car tires, bicycle tubes have Schrader or Presta valves, with most of the higher bikes having Presta valves. Both Schrader and Presta types are good at sealing high pressure. Their main difference is that the Schrader valve is larger and has a spring that closes the valve except when the pin is pressed. Schrader valves are used in various types of compressed gases and applications of pressurized liquids such as small torches and grille cylinders, and air shocks. The Schrader valve is also seen as more complex (requires two more than one seal), and is heavier than the Presta valve.
The Presta valve rod is 6 mm in diameter, while the Schrader valve rod for bicycle tires is 8 mm, thus requiring larger diameter holes in the bicycle rims. Although there is no concern for the wider rim of the bike, it will weaken the narrow wheel rim, preventing its use on racing bikes (roads). Another disadvantage of Schrader is that the air chuck must hit the spring pin before air can flow during inflation (and potentially insert the debris into the tube or seal inside the valve), while the Presta valve relies on a small knurled nut to keep the lid. To fill a bicycle tire with a Presta-valved tube in a gas station requires an adapter, while a Schrader-valved tube does not. Cyclists also need to purchase a Presta pump, or more commonly a double valve-capable pump for both Schrader and Presta valves. At this point, most CO2 inflators are also just Presta, although some manufacturers are developing a compatible head of the Schrader inflator that uses pressure to open Schrader's valve. Presta valves are also available in a wide range of bar lengths for aero-bike rims. The detachable core of the Presta valve has become common in many applications, especially tubeless tires where the ability to introduce sealants to tires via a rod is considered useful.
Dunlop ("England") valves are sometimes used on bicycles in certain countries including Japan and the Netherlands, but are rarely found in the United States. The Dunlop valve is compatible with the Presta inflator.
Dimensions
External thread: UNEF 5/16x32 fine thread
Internal thread: 0.209 in OD x 36 TPI
References
External links
- TRA (The Tire and Rim Association, Inc.)
- Schrader-Bridgeport International
Source of the article : Wikipedia
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