Steam Engine Design/Historic - Revision history

Mjn at 03:07, 30 May 2011

2011-05-30T03:07:22Z

← Older revision		Revision as of 03:07, 30 May 2011
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	{{Category=Steam Engine}}		{{Category=Steam Engine}}
			[[Steam Engine Research]]

	=Engines=		=Engines=

Mjn at 03:13, 23 May 2011

2011-05-23T03:13:13Z

← Older revision		Revision as of 03:13, 23 May 2011
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	=Engines=		=Engines=

	~~(Reference the~~ Wikipedia article ~~here)~~		See Wikipedia article on Steam Engines [http://en.wikipedia.org/wiki/Steam_engine].

	==Uniflow Engines==		==Uniflow Engines==

Mjn: spelling in horz. vs. vertical section

2011-05-23T02:15:43Z

spelling in horz. vs. vertical section

← Older revision		Revision as of 02:15, 23 May 2011
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	From ''Steam Engineering: A Text Book'' by William R. King		From ''Steam Engineering: A Text Book'' by William R. King

	Of the two ~~form sof~~ engines, the ''horizontal'' and ''vertical'', the former is very generally ~~usind~~ in plants of small and moderate powers. it is cheaper in construction and much more accessible for inspection and repair than the vertical engine, though it occupies more floor space. The main objection to horizontal engines of large power is the difficulty of supporting the weight of the piston and preventing it from cutting the cylinder and wearing it ~~outo f~~ true when traveling at the high piston ~~spseeds~~ required in modern practice.		Of the two forms of engines, the ''horizontal'' and ''vertical'', the former is very generally used in in plants of small and moderate powers. it is cheaper in construction and much more accessible for inspection and repair than the vertical engine, though it occupies more floor space. The main objection to horizontal engines of large power is the difficulty of supporting the weight of the piston and preventing it from cutting the cylinder and wearing it out of true when traveling at the high piston speeds required in modern practice.

	It is because of this objection that the vertical engine is used in plants of large power. The shaft of a vertical engine rests in ~~bearnigs~~ which are part of the bed plat that rests on the foundation, the cylinder being held in vertical framing, thus throwing the weight of the piston on the bearings. The vertical engines runs more ~~smootly~~ and with a ~~greatermechanical~~ efficiency than the horizontal engine, due to the fact that the unbalanced forces inseparable from the operation ~~fo teh~~ steam engine are more easily counteracted. In accessibility for repairs and the excessive head room required are it's chief disadvantages.		It is because of this objection that the vertical engine is used in plants of large power. The shaft of a vertical engine rests in bearings which are part of the bed plat that rests on the foundation, the cylinder being held in vertical framing, thus throwing the weight of the piston on the bearings. The vertical engines runs more smoothly and with a greater mechanical efficiency than the horizontal engine, due to the fact that the unbalanced forces inseparable from the operation of the steam engine are more easily counteracted. In accessibility for repairs and the excessive head room required are it's chief disadvantages.

Mjn at 02:13, 23 May 2011

2011-05-23T02:13:35Z

← Older revision		Revision as of 02:13, 23 May 2011
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	A careful examination of the slide valve (in black, center) shows the flow of steam into the left side of the cylinder while venting steam out of the right.		A careful examination of the slide valve (in black, center) shows the flow of steam into the left side of the cylinder while venting steam out of the right.

			==Horizontal vs. Vertical Engines==

			From ''Steam Engineering: A Text Book'' by William R. King

			Of the two form sof engines, the ''horizontal'' and ''vertical'', the former is very generally usind in plants of small and moderate powers. it is cheaper in construction and much more accessible for inspection and repair than the vertical engine, though it occupies more floor space. The main objection to horizontal engines of large power is the difficulty of supporting the weight of the piston and preventing it from cutting the cylinder and wearing it outo f true when traveling at the high piston spseeds required in modern practice.

			It is because of this objection that the vertical engine is used in plants of large power. The shaft of a vertical engine rests in bearnigs which are part of the bed plat that rests on the foundation, the cylinder being held in vertical framing, thus throwing the weight of the piston on the bearings. The vertical engines runs more smootly and with a greatermechanical efficiency than the horizontal engine, due to the fact that the unbalanced forces inseparable from the operation fo teh steam engine are more easily counteracted. In accessibility for repairs and the excessive head room required are it's chief disadvantages.


	=Valve Design=		=Valve Design=

Mjn: /* Continuous Flow Engines */

2011-05-23T01:16:23Z

Continuous Flow Engines

← Older revision		Revision as of 01:16, 23 May 2011
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	[[Image:Steam-Engine-Cont-Flow.png]]		[[Image:Steam-Engine-Cont-Flow.png]]

			A careful examination of the slide valve (in black, center) shows the flow of steam into the left side of the cylinder while venting steam out of the right.

	=Valve Design=		=Valve Design=

Mjn: /* Engine Valve Design */

2011-05-23T01:14:25Z

Engine Valve Design

← Older revision		Revision as of 01:14, 23 May 2011
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	[[Image:Steam-Engine-Cont-Flow.png]]		[[Image:Steam-Engine-Cont-Flow.png]]

	=~~=Engine~~ Valve Design==		=Valve Design=

	There are several common styles of conventional valves in steam engines		There are several common styles of conventional valves in steam engines

Mjn: /* Engine */

2011-05-23T01:13:54Z

Engine

← Older revision		Revision as of 01:13, 23 May 2011
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	{{Category=Steam Engine}}		{{Category=Steam Engine}}

	=~~=Engine=~~=		=Engines=

	(Reference the Wikipedia article here)		(Reference the Wikipedia article here)

			==Uniflow Engines==

			In a uniflow engine steam is admitted only on one side of the piston. At the point of maximum expansion of the steam, an exhaust vent is exposed allow remaining steam to vent. Thus, steam flows in a single direction: into the cylinder, then out of it. Steam control is done via a ball, bump, or piston valve.

			[[Image:Design-5-A.png]]

			==Continuous Flow Engines==

			In a continuous flow engine, steam is admitted on either side of the piston, depending on it's position in the stroke. Typically, a slide valve is used to alternately admit steam into one side of the piston or the other and vent spent steam.

			[[Image:Steam-Engine-Cont-Flow.png]]

	==Engine Valve Design==		==Engine Valve Design==

Mjn: /* Engine Valve Design */

2011-05-09T21:18:05Z

Engine Valve Design

← Older revision		Revision as of 21:18, 9 May 2011
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	* cam actuated poppet valve		* cam actuated poppet valve
	* bump (or bash) valve		* bump (or bash) valve
			* slide valve

	Some illustration of slide valve designs:		Some illustration of slide valve designs:

Mjn: Created page with "{{Category=Steam Engine}} ==Engine== (Reference the Wikipedia article here) ==Engine Valve Design== There are several common styles of conventional valves in steam engines *..."

2011-05-01T20:11:01Z

Created page with "{{Category=Steam Engine}} ==Engine== (Reference the Wikipedia article here) ==Engine Valve Design== There are several common styles of conventional valves in steam engines *..."

New page

{{Category=Steam Engine}}

==Engine==

(Reference the Wikipedia article here)

==Engine Valve Design==

There are several common styles of conventional valves in steam engines

* slide valve
* piston slide valve
* cam actuated poppet valve
* bump (or bash) valve

Some illustration of slide valve designs:

<gallery widths="350px" heights="500px" perrow="2">
File:Slide_Valve_Without_Valve_Gear.JPG
File:Piston_Slide_valve.jpg
File:Poppet_Valve_Construction.JPG
</gallery>

Each of these has their own advantages and disadvantages often depending on steam conditions and desired durability. Please consult an engineering manual such as [http://books.google.com/books?id=NsNCAAAAIAAJ&printsec=frontcover&dq=valves+and+valve+gears&as_brr=1 ''Valves And Valve Gears''] for a detailed discussion of this.

For the simple valves shown above it is not possible to vary the steam cutoff ratio during operation. This usually detrimentally impacts efficiency as one has to set the cutoff ratio higher than needed to keep the engine from stalling during load variation. For this reason a multitude of valve gears were developed for the three basic types of valve designs. The valve gears allow for the adjustment of the cutoff ratio during operation.

Slide Valve and Piston Slide Valve Valve Gears

<gallery widths="350px" heights="500px" perrow="2">
File:Stephenson Valve gear.JPG
File:Marshall Gear.JPG
File:Stevens Gear.JPG
File:Joy Gear.JPG
File:Hackworth Gear.JPG
File:Gooch Gear.JPG
File:Fink Gear.JPG
File:Baker Gear.JPG
File:Allen gear.JPG
</gallery>

Poppet Valve Valve Gears

<gallery widths="350px" heights="500px" perrow="2">
File:Sulzer Gear (poppet).JPG
File:Lentz Gear (poppet).JPG
File:Skinner Universal Unaflow (Double acting Poppet).JPG
File:Walschaert Gear.JPG
</gallery>