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Valve stem

From Wikipedia, the free encyclopedia
For the shaft which transmits motion from the outside to the inside of a valve, see Valve § Stem.
Replacing a valve stem.

A valve stem is a self-contained valve that opens to admit gas to a chamber (such as air to inflate a tire),[1] and is then automatically closed and kept sealed by the pressure in the chamber, or a spring,[2][3] or both, to prevent the gas from escaping.[4]

There are many types of valves, and they are most commonly used on automobile, motorcycle, and bicycle tires, but also for many other applications. The most common type is the Schrader valve, but some road bicycles with skinny tires instead use the Presta valve.[5][6][7][8]

Schrader

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Schrader valve stem
Main article: Schrader valve

Schrader valves consist of a valve stem into which a poppet valve is threaded with a spring attached. They are used on virtually all automobile and motorbike tires and on wider-rimmed bicycle tires. In addition to tires, Schrader valves of varying diameters are used in refrigeration and air conditioning systems, plumbing, engine fuel injection, suspension systems, and SCUBA regulators, allowing the user to remove and attach a hose while in use. The Schrader valves in the fuel injector rail of many automobiles are used as a quick and easy point to check fuel pressure or connect an injector cleaner cartridge.[9][10][11][12][13][14][15][16]

Presta

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Presta valve stem
Main article: Presta valve

Presta valves (also called Sclaverand valves or French valves) are normally only used on bicycles. The stem has a narrower diameter (nominally 6 mm) than the thinnest (nominally 8 mm) Schrader type, and so the bore of the hole in the rim through which the stem passes can be smaller. Has a locknut that needs to be opened to inflate/deflate.[17][18]

Dunlop (or Woods)

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Dunlop (or Woods) valve stem
Main article: Dunlop valve

Dunlop valves (also called Woods valves or English valves) were the dominating bicycle valves in the European region and many other countries. As of 2021, Presta valves are just as common in these regions. Dunlop valves are still widely used especially on low to medium-priced bicycles (city and trekking bikes).[19] They can be pumped up with a Presta bicycle pump.[20]

Regina

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Regina Valve stem

The "Regina Valve" is very similar to the Presta and mostly used in Italy.[21][circular reference] The central threaded pin is so short that it does not protrude from the valve tube and therefore cannot be bent. In order to close the valve tightly, a small, loose nut is placed on this threaded rod with a diameter of only around 1.5 mm and screwed on by hand. A threaded rod is enough. By tightening the nut, the valve disc with the conical sealing body is pressed against the valve seat.

Rim drilling:⌀ 6.5 mm

Thread DIN 7756 • outside VG 6×32 •outside VG 5.2×24 at the upper end

Maximum pressure 15 bars.

Others

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Many other valves are used only in certain regions or for limited purposes.

Invisible tire valves are different in design from traditional tire valves. An inflator stem is not used; instead, a removable cap on a valve stem embedded in the tire rim is fitted, with only the cap visible. When inflating the tire, the cap is first removed, typically with a coin, and then a "portable" dedicated inflator stem is screwed onto the valve stem. Through the inflator, the tire is inflated as usual.

References

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  1. ^ García-Ramírez, Yasmany (2022). "Real Driving on Under-inflated Rear Tire on Horizontal Curves: A Road Experimental Study". Proceedings of the 8th International Conference on Vehicle Technology and Intelligent Transport Systems. SCITEPRESS - Science and Technology Publications. doi:10.5220/0011056900003191.
  2. ^ "Pressure". Pressure. 2020. doi:10.5040/9781682661031.
  3. ^ Tools for pressing. Spring plungers with helicoidal compression steel spring or gas spring, BSI British Standards, retrieved 2023-09-25
  4. ^ Hydraulic fluid power. Pressure reducing valves, sequence valves, unloading valves, throttle valves and check valves. Mounting surfaces, BSI British Standards, retrieved 2023-09-25
  5. ^ "Handmade Automobiles". Handmade Automobiles. 2009. doi:10.5040/9781350904057.
  6. ^ Motorcycle Headlamps, SAE International, retrieved 2023-09-25
  7. ^ "The Repair of Single Tube Bicycle Tires". Scientific American. 75 (5): 125–126. 1896-08-01. doi:10.1038/scientificamerican08011896-125. ISSN 0036-8733.
  8. ^ Hydraulic fluid power. Pressure reducing valves, sequence valves, unloading valves, throttle valves and check valves. Mounting surfaces, BSI British Standards, retrieved 2023-09-25
  9. ^ Eugene A. Sloane (1991). Sloane's Complete Book of All-terrain Bicycles. Simon and Schuster. pp. 313–. ISBN 978-0-671-67587-5.
  10. ^ "poppet valve, n.", Oxford English Dictionary, Oxford University Press, 2023-03-02, retrieved 2023-09-25
  11. ^ Karmakar, Sibdas; Karmakar (2022-02-16), "Diameters and Conjugate Diameters", Analytical Geometry: Two Dimensions, London: CRC Press, pp. 273–300, retrieved 2023-09-25
  12. ^ "Air conditioning system cost", Air Conditioning, Routledge, pp. 367–373, 2014-05-09, ISBN 978-1-315-79406-8, retrieved 2023-09-25
  13. ^ Pressure regulators for use with medical gases, BSI British Standards, retrieved 2023-09-25
  14. ^ "Unit 1 Welcome to Plumbing", Plumbing, Routledge, pp. 13–32, 2007-08-15, ISBN 978-0-08-055005-3, retrieved 2023-09-25
  15. ^ Marine Carburetors and Fuel Injection Throttle Bodies, SAE International, retrieved 2023-09-25
  16. ^ Bauer, Wolfgang (2021-10-01), "Suspension Systems Basics", Hydropneumatic Suspension Systems, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 1–22, ISBN 978-3-662-63771-5, retrieved 2023-09-25
  17. ^ Christopher Wiggins (5 June 2014). Bike Repair and Maintenance. DK Publishing. pp. 16–. ISBN 978-1-61564-511-4.
  18. ^ Hydraulic fluid power. Pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves. Mounting surfaces, BSI British Standards, retrieved 2023-09-25
  19. ^ Hydraulic fluid power. Pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves. Mounting surfaces, BSI British Standards, retrieved 2023-09-25
  20. ^ Sheldon Brown's Bicycle Glossary
  21. ^ "Fahrradventil". Wikipedia DE. Retrieved 27 March 2023.
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