Priming: Difference between revisions
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(Created page with "Category:Definitions Priming (foaming in North America) is a condition in the boiler of a steam locomotive in which water is carried over into the steam delivery. It may ...") |
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Priming (foaming in North America) is a condition in the boiler of a steam locomotive in which water is carried over into the steam delivery. It may be caused by impurities in the water, which foams up as it boils, or simply too high a water level. It is harmful to the valves and pistons, as lubrication is washed away, and can be dangerous as any water collecting in the cylinders is not compressible and if trapped may fracture the cylinder head or piston. | Priming (foaming in North America) is a condition in the boiler of a steam locomotive in which water is carried over into the steam delivery. It may be caused by impurities in the water, which foams up as it boils, or simply too high a water level. It is harmful to the valves and pistons, as lubrication is washed away, and can be dangerous as any water collecting in the cylinders is not compressible and if trapped may fracture the cylinder head or piston. | ||
From [[Gary Kubicek Loco-Notes]]: | |||
: We know that as the pressure in a boiler gets higher, so does the temperature of the water in the boiler. If this pressure is suddenly decreased, the water erupts or violently changes to steam. This sudden decrease in pressure occurs immediately under a safety valve each time the safety valve releases and, if the water is carried high in the boiler, the violent change of water to steam carries some water out the safety valve giving quite a shower - this is referred to as [[Priming|priming]]. | |||
: [[File:Priming with Safety Valve over Crown Sheet.PNG|thumb|center|500px|Priming with Safety Valve over Crown Sheet]] | |||
== References == | == References == | ||
* [http://en.wikipedia.org/wiki/Priming_%28steam_locomotive%29 "Priming", <i>Wikipedia</i>] | * [http://en.wikipedia.org/wiki/Priming_%28steam_locomotive%29 "Priming", <i>Wikipedia</i>] | ||
Revision as of 10:27, 15 May 2021
Priming (foaming in North America) is a condition in the boiler of a steam locomotive in which water is carried over into the steam delivery. It may be caused by impurities in the water, which foams up as it boils, or simply too high a water level. It is harmful to the valves and pistons, as lubrication is washed away, and can be dangerous as any water collecting in the cylinders is not compressible and if trapped may fracture the cylinder head or piston.
From Gary Kubicek Loco-Notes:
- We know that as the pressure in a boiler gets higher, so does the temperature of the water in the boiler. If this pressure is suddenly decreased, the water erupts or violently changes to steam. This sudden decrease in pressure occurs immediately under a safety valve each time the safety valve releases and, if the water is carried high in the boiler, the violent change of water to steam carries some water out the safety valve giving quite a shower - this is referred to as priming.
