Slide valve - Revision history

Red marquis at 04:44, 2 March 2010

2010-03-02T04:44:31Z

← Older revision		Revision as of 04:44, 2 March 2010
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	~~[[File:Slide-valve cylinder, three-quarter view (Heat Engines, 1913).jpg\|thumb\|right\|Cylinder, with slide valve removed to show ports]]~~		The '''slide valve''' is a rectilinear valve used to control the admission of steam into, and emission of exhaust from, the cylinder of a steam engine.
	[[File:Slide-valve_cylinder,_section_(Heat_Engines,_1913).jpg\|right\|thumb\|280px\|A double-acting slide valve cylinder.<br />Steam enters via the steam port ''SP'', and is admitted by the slide valve ''SV''  through the upper passage ''S''  to push down the piston ''P''. At the same time, exhaust steam from below the piston passes back up the lower passage ''S'', via the valve cavity, to exhaust ''E''. As the piston descends, the valve moves upwards to admit steam below the piston and release exhaust from above.]]
	The '''slide valve''' is a [[rectilinear]] valve used to control the admission of steam into, and emission of exhaust from, the cylinder of a steam engine.
	[[File:Steam_engine_slide-valve_cylinder_animation.svg\|thumb\|right\|The [[:File:Steam_engine_slide-valve_cylinder_animation.svg\|image description page]] explains how this [[Scalable vector graphics\|SVG]] animation can be viewed]]

	==Use==		==Use==
	In the 19th century, most steam locomotives used slide valves to control the flow of steam into and out of the [[~~Cylinder (steam locomotive)\|~~cylinder]]s. In the 20th century, slide valves were gradually superseded by [[piston valves]], particularly in engines using ~~[[Superheater\|~~superheated]] steam. There were two reasons for this:		In the 19th century, most steam locomotives used slide valves to control the flow of steam into and out of the [[cylinder]]s. In the 20th century, slide valves were gradually superseded by [[piston valves]], particularly in engines using superheated steam. There were two reasons for this:

	* With piston valves, the steam passages can be made shorter. This reduces resistance to the flow of steam and improves efficiency.		* With piston valves, the steam passages can be made shorter. This reduces resistance to the flow of steam and improves efficiency.
	* It is difficult to ~~[[Lubrication\|~~lubricate]] slide valves adequately in the presence of superheated steam.		* It is difficult to lubricate slide valves adequately in the presence of superheated steam.

	~~{{clear}}~~
	== Murdoch's D slide valve ==		== Murdoch's D slide valve ==
	~~[[File:Murdoch's long D slide valve (Jamieson, Elementary Manual on Heat Engines).jpg\|thumb\|right\|Murdoch's long D slide valve]]~~
	The '''D slide valve''', or more specifically '''Long D slide valve''', is a form of slide valve, invented by [[William Murdoch]] and patented in 1799. It is named after the hollow central D-sectioned piston.		The '''D slide valve''', or more specifically '''Long D slide valve''', is a form of slide valve, invented by [[William Murdoch]] and patented in 1799. It is named after the hollow central D-sectioned piston.

	This valve worked by "connecting the upper and lower valves so as to be worked by one rod or spindle, and in making the stem or tube which connects them hollow, so as to serve for an induction pipe to the upper end of the cylinder." This allowed two valves to do the work of four.		This valve worked by "connecting the upper and lower valves so as to be worked by one rod or spindle, and in making the stem or tube which connects them hollow, so as to serve for an induction pipe to the upper end of the cylinder." This allowed two valves to do the work of four.

	The above description (referring to upper and lower valves) clearly relates to an engine with a vertical cylinder, such as a [[beam engine]]. Where the cylinders are horizontal, as in a [[steam locomotive]], the valves would be side-by-side.		The above description (referring to upper and lower valves) clearly relates to an engine with a vertical cylinder, such as a beam engine. Where the cylinders are horizontal, as in a steam locomotive, the valves would be side-by-side.

	==Balanced slide valve==		==Balanced slide valve==
	The balanced slide valve was invented by the ~~[[Scotland\|~~Scottish]] engineer [[Alexander Allan ~~(locomotive engineer)\|Alexander Allan]]~~. It was not much used in the [[UK]] but, at one time, had great popularity in the [[USA]]. It gave some of the advantages of a piston valve to a slide valve by relieving the pressure on the back of the valve, thus reducing friction and wear.		The balanced slide valve was invented by the Scottish engineer Alexander Allan. It was not much used in the UK but, at one time, had great popularity in the USA. It gave some of the advantages of a piston valve to a slide valve by relieving the pressure on the back of the valve, thus reducing friction and wear.

	==See also==		==See also==
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	==External links==		==External links==
	~~{{commonscat\|Steam engines with slide valves}}~~
	* [http://oldenginehouse.users.btopenworld.com/slide.htm The Slide Valve]		* [http://oldenginehouse.users.btopenworld.com/slide.htm The Slide Valve]

	~~{{Machine configurations\|state=uncollapsed}}~~

	[[Category:Engine valves]]		[[Category:Engine valves]]
	[[Category:Engines]]		[[Category:Engines]]
	[[Category:Engine technology]]		[[Category:Engine technology]]

Red marquis at 04:42, 2 March 2010

2010-03-02T04:42:15Z

← Older revision		Revision as of 04:42, 2 March 2010
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	[[Category:Engine valves]]		[[Category:Engine valves]]
	[[Category:~~Engine~~]]		[[Category:Engines]]
	[[Category:Engine technology]]		[[Category:Engine technology]]

Red marquis at 04:41, 2 March 2010

2010-03-02T04:41:43Z

New page

[[File:Slide-valve cylinder, three-quarter view (Heat Engines, 1913).jpg|thumb|right|Cylinder, with slide valve removed to show ports]]
[[File:Slide-valve_cylinder,_section_(Heat_Engines,_1913).jpg|right|thumb|280px|A double-acting slide valve cylinder.<br />Steam enters via the steam port ''SP'', and is admitted by the slide valve ''SV''  through the upper passage ''S''  to push down the piston ''P''. At the same time, exhaust steam from below the piston passes back up the lower passage ''S'', via the valve cavity, to exhaust ''E''. As the piston descends, the valve moves upwards to admit steam below the piston and release exhaust from above.]]
The '''slide valve''' is a [[rectilinear]] valve used to control the admission of steam into, and emission of exhaust from, the cylinder of a steam engine.
[[File:Steam_engine_slide-valve_cylinder_animation.svg|thumb|right|The [[:File:Steam_engine_slide-valve_cylinder_animation.svg|image description page]] explains how this [[Scalable vector graphics|SVG]] animation can be viewed]]

==Use==
In the 19th century, most steam locomotives used slide valves to control the flow of steam into and out of the [[Cylinder (steam locomotive)|cylinder]]s. In the 20th century, slide valves were gradually superseded by [[piston valves]], particularly in engines using [[Superheater|superheated]] steam. There were two reasons for this:

* With piston valves, the steam passages can be made shorter. This reduces resistance to the flow of steam and improves efficiency.
* It is difficult to [[Lubrication|lubricate]] slide valves adequately in the presence of superheated steam.

{{clear}}
== Murdoch's D slide valve ==
[[File:Murdoch's long D slide valve (Jamieson, Elementary Manual on Heat Engines).jpg|thumb|right|Murdoch's long D slide valve]]
The '''D slide valve''', or more specifically '''Long D slide valve''', is a form of slide valve, invented by [[William Murdoch]] and patented in 1799. It is named after the hollow central D-sectioned piston.

This valve worked by "connecting the upper and lower valves so as to be worked by one rod or spindle, and in making the stem or tube which connects them hollow, so as to serve for an induction pipe to the upper end of the cylinder." This allowed two valves to do the work of four.

The above description (referring to upper and lower valves) clearly relates to an engine with a vertical cylinder, such as a [[beam engine]]. Where the cylinders are horizontal, as in a [[steam locomotive]], the valves would be side-by-side.

==Balanced slide valve==
The balanced slide valve was invented by the [[Scotland|Scottish]] engineer [[Alexander Allan (locomotive engineer)|Alexander Allan]]. It was not much used in the [[UK]] but, at one time, had great popularity in the [[USA]]. It gave some of the advantages of a piston valve to a slide valve by relieving the pressure on the back of the valve, thus reducing friction and wear.

==See also==
* [[Valve gear]]
* [[Piston valves|Piston Valve]]
* [[Poppet valve]]
* [[Sleeve valve]]
* [[Corliss valve]]

==External links==
{{commonscat|Steam engines with slide valves}}
* [http://oldenginehouse.users.btopenworld.com/slide.htm The Slide Valve]

{{Machine configurations|state=uncollapsed}}

[[Category:Engine valves]]
[[Category:Engine]]
[[Category:Engine technology]]