Talk:Piston

message: Am I the only one who noticed that the introduction is worded funny?
"In general, a piston is a lubricated sliding shaft that fits tightly inside the opening of a cylinder. Its purpose is to change the volume enclosed by the cylinder, to exert a force on a fluid inside the cylinder, to cover and uncover ports, or some combination of these. A rubber seal is sometimes used to keep the lubricate within the shaft. Due to the constant motion of the machine this seal wears quickly and should be replaced with every servicing. If the seal should break during usage there can be disastrous long lasting consequences for the machine."
If it is, is there a way to reword this?
SniperWolf1564 10:57, 16 May 2007 (UTC)
replies: text: I agree that the introduction was awful and I have re-written it. Biscuittin (talk) 11:09, 30 March 2008 (UTC)
thread_title:  Poorly worded introduction? 

message: Hello. Does anybody heard about a new kind of piston, connected to a shaft? Such piston have angular motion (rather than linear motion) and produces less friction to the chamber walls.
A while ago I saw a documentary (in Discovery Channel or BBC, doesn't fully remember) that shows a Japanese engine that uses such piston. I think it would enrich this article.
If anybody know piston specifications mail to me at : karthirevi@rediffmail.com (I did: Nikevich (talk) 01:59, 11 November 2010 (UTC)
thread_title:  Angular Moving Piston 

message: Is there no article on piston seizures in the English language WP (cause and effect)? In the German language WP, there is :de:Kolbenfresser. --Abe Lincoln 15:07, 11 October 2006 (UTC)
thread_title:  [[Piston seizure]] 

message: hello, could anyone tell me the length of time that a piston is still for between directions (from down back up ) and also is there a name for this. Thanks
:Whilst the crank is turning the piston only stops instantaneously at the top and bottom of it's stroke. These are known as 'top dead centre' and 'bottom dead center' respectively.
The exact amount of time spent at top and bottom dead centre depends on the speed of rotation of the connecting crankshaft and the amount of play at the big and small ends. As long as the crankshaft is running at a continuous speed and any play in the big and small end is negligible why should the piston connected to it spend any more time at angle zero as at any other angel of its rotation?
AdrianAbel (talk) 12:05, 29 April 2008 (UTC)
thread_title:  timing 

message: I am attempting to model the flow in and out of a single piston cylinder arrangement.  
On the down stroke the pressure in the cylinder decreases and a one way valve opens to admit fluid into the cylinder, on the up stroke the other one way valve opens (and the first closes) as the piston “pushes” fluid out of the cylinder.  
I will firstly begin modeling assuming the fluid in the cylinder is incompressible but later as the model becomes more complex I will model using compressible theory gas theory.  
If any one has any information or knows where I can get any information on the basic formulations of the energy, continuity and momentum equations could you please email me at:  14107864@sun.ac.za
Thank you
Paul
Suggest physics and mechanical-engineering texts, handbooks, and/or courses. Sorry not to be of more help. Nikevich (talk) 01:59, 11 November 2010 (UTC)
thread_title:  Governing equations 

message: I am an engineer and I can not believe what is happening here. I can not find a word about materials for piston, and than I tried plunger, and I discovered an engineering article there. Wow--Billy the lid (talk) 08:55, 27 December 2007 (UTC)
replies: text: Hey Billy,
A new article for called "Piston pump" still needs to be made; at present it simply links to this article; so the redirect needs removing and text has to be added. I made an additional image for the types of piston pumps which can be added to that article: File:Piston pump types.png
KVDP (talk) 09:25, 27 May 2010 (UTC)
thread_title:  Piston and plunger 

message: The introduction assumes that all pistons are reciprocating, hence implying that all are continuously moving. This is clearly wrong (see the first query on this talk page). What about the piston used in a Pneumatic cylinder? That article links here, but there is no suggestion here that a piston could be part of a linear actuator of some kind. -- EdJogg (talk) 13:15, 18 August 2010 (UTC)
thread_title:  What about a piston for a [[Pneumatic cylinder]]? 

message: I just deleted a discussion line about magnetically moving pistons, it seemed not serious, but then I started searching about the subject on the net and found lots of things. I'm wondering if it should not be mentioned in the article.  —Preceding unsigned comment added by 70.187.173.135 (talk) 16:12, 30 October 2010 (UTC)
thread_title:  Magnetic pistons? 

message: Double-acting cylinders (usually, if not always pneumatic) do not necessarily have piston rods. It is likely to amaze people who know something of technology, but, there are several companies who make these, and they are a commercial success. I'm not sure about high-flux magnets installed into the piston that "couple" with external magnets (or just solid ferromagnetic pieces), but there are definitely rodless cylinders with a relatively-wide slot in the cylinder wall. A sealing strip prevents leakage, and the piston is relatively long -- maybe 3 or4 times its diameter. Piston rings (O-rings or other) are at both ends, and the center portion, as it moves, "peels" off the sealing strip, permitting the actuator to move through the slot. At the other end, an identical structure "re-applies" the sealing strip. There probably are wipers for the slot edges and the strip.
This topic should be part of an article (again, not checking) about rodless cylinders, better yet, part of an article about cylinders in mech. engineering in general. Nikevich (talk) 01:59, 11 November 2010 (UTC)
thread_title: Pistons for rodless cylinders

message: This should be an article about a piston - not a piston engine.
There should be explained the parts of a piston, for instance what is a "Piston skirt" etc.
Is it called wall, skirt, mantle, mantel? no help from wikipedia.--173.170.92.3 (talk) 17:02, 20 January 2011 (UTC)
thread_title: Piston skirt?

message: The section "Internal combustion engines" has become a discussion of the merits and disadvantages of two-stroke and four-stroke engines, which has nothing to do with the pistons themselves. This discussion can be found elsewhere in other WP articles, and has no place here. Chris the speller yack 16:49, 7 December 2011 (UTC)
replies: text: Delete the whole article. There's barely a line in here that achieves any sort of encyclopedic standard. Andy Dingley (talk) 16:50, 7 December 2011 (UTC)
thread_title:  Two-stroke vs. four-stroke — text removed 

message: Removed from "Drawbacks section":
Chris the speller yack 23:07, 7 December 2011 (UTC)
thread_title:  More off-topic text removed 

message: Quote:
These engines typically use crosshead pistons. The main piston has a large piston rod extending downwards from the piston to what is effectively a second smaller-diameter piston. The main piston is responsible for gas sealing and carries the piston rings. The smaller piston is purely a mechanical guide. It runs within a small cylinder as a trunk guide and also carries the gudgeon pin. Because of the additional weight of these pistons, they are not used for high-speed engines
Unquote
There is no machinery part named crossheead piston, such thing does not exist. Crosshead is not smaller diameter piston, it is not even circular, it is straight line bearing consisting of shoe and guide. There is no another gudgeon pin, and best of all is last comment. Crosshead is mounted on engines where trunk system can not perform the task of annulating side forces well enough. Side forces in engines grow with size of piston and its weight, therefore crossheads can be found on engines with large bore, mainly with bore over 300-400 mm. (MAN is world leading manufacturer of crosshead engines, starts from 350 mm)  — Preceding unsigned comment added by 93.137.29.202 (talk) 11:01, 9 May 2013 (UTC)
thread_title: Please remove following nonsence

message: Shouldn't there be a subsection regarding the history of the piston/cylinder invention, particularly pertaining to steam engines, and preceded by the motion of automatic safety valves (for limiting boiler pressure)? Cesiumfrog (talk) 12:54, 7 January 2014 (UTC)
replies: text: There should be a whole article here, where at the moment we have almost nothing. The invention of the steam engine piston (Papin 1690, although some claim Huygens; also the Russians have a doubtful claim that Polzunov was the first with a workable piston actuated by steam pressure rather than atmospheric pressure against a condensed vacuum) is relatively simple and the gradual development of its seal is the interesting part. The development of the machinery for machining an accurate cylinder is by far the most important and complex aspect - we could have a whole article on that alone. Safety valve, which AFAIK has relatively little direct connection to the piston's history, is a much more complete article than piston. Andy Dingley (talk) 13:13, 7 January 2014 (UTC)
thread_title:  history 

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