Tundish
{{Short description|Funnel-like device used in plumbing and metal casting}}
The word tundish originates from a shallow wooden dish with an outlet channel, fitting into the bunghole of a tun or cask and forming a kind of funnel for filling it. These were originally used in brewing.
In general, any tundish will accept flow and store a small amount of material, while dispensing material elsewhere, similar to a funnel. In contrast to a funnel, the purpose is generally to regulate flow, and achieve a more steady output with intermittent inputs, and the tundish typically will take on a different shape.
Plumbing
The term tundish is still used today in plumbing, where a funnel or hopper is filled by an outlet pipe above it. This is often provided for intermittent overflows, or where an air gap is required, to avoid possible back-contamination.{{cite book
|last=Treloar |first=R.D.
|title=Plumbing
|publisher=Blackwell
|edition=3rd
|year=2006
|isbn=978-1-4051-3962-5
|ref=Treloar, Plumbing
|pages=106, 150
}}
Rohrbeluefter_E.0127.jpg|An atmospheric vacuum breaker with a tundish
Rohrbelüfter_E.png|Functional schematic (labelled in German)
Metal casting
In metal casting, a tundish is a broad, open container with one or more holes in the bottom. It is used to feed molten metal into an ingot mould to avoid splashing and give a smoother flow. The tundish allows a reservoir of metal to feed the casting machine while ladles are switched, thus acting as a buffer of hot metal, as well as smoothing out flow, regulating metal feed to the moulds and cleaning the metal. Metallic remains left inside a tundish are known as tundish skulls{{cite web |url=http://www.websters-online-dictionary.org/Sk/Skull.html |title=Skull |accessdate=2007-08-13 |url-status=dead |archiveurl=https://web.archive.org/web/20070930190011/http://www.websters-online-dictionary.org/Sk/Skull.html |archivedate=2007-09-30 }} and need to be removed, typically by mechanical means (scraping, cutting). A casting tundish is lined with refractory bricks specific to the liquid metal which is being cast. A tundish preheater may improve performance by heating the refractory before pouring metal, and may allow removal of molten oxide and skull material while preheating.{{Cite patent|title=Method of preheating a tundish|country=US|number=3782596|pubdate=1974-01-01|assign1=United States Steel Corp.|inventor1-last=Griffiths|inventor1-first=David K.}}
References
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