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Encyclopedia > Piston valve
Piston valve in a brass instrument

A piston valve is a device used to control the motion of a fluid along a tube or pipe by means of the linear motion of a piston within a chamber or cylinder. File links The following pages link to this file: Brass instrument User talk:CompUTOSer Categories: GFDL images ... File links The following pages link to this file: Brass instrument User talk:CompUTOSer Categories: GFDL images ... Image of a trumpet. ... A fluid is defined as a substance that continually deforms (flows) under an applied shear stress regardless of the magnitude of the applied stress. ... Tubing refers to a flexible hose or pipe used in plumbing, irrigation, and other industries. ... Pipe is a tube or hollow cylinder for the conveyance of fluid. ... The word linear comes from the Latin word linearis, which means created by lines. ... piston + connecting rod Components of a typical, four stroke cycle, DOHC piston engine. ... Look up chamber in Wiktionary, the free dictionary. ... Cylinder with piston in a steam engine A cylinder in the central working part of a reciprocating engine, the space in which a piston travels. ...


Examples of piston valves are:

Contents

The Walschaert valve gear on a steam locomotive (a PRR E6s). ... // The term steam engine may also refer to an entire railroad steam locomotive. ... Union Pacific Big Boy #4012 at work on a cold November 29, 1941 A steam locomotive is a locomotive powered by steam. ... Image of a trumpet. ...

Pneumatic cannons

Piston valves are some of the most powerful available in spudgunning (Spud guns), with the ability to dump several litres of pressurised air in a few thousands of a second. This fast moving air is used to fire a projectile from the exhaust barrel. As the name suggests they are used to fire vegetables, such as potatoes; wood, to simulate hurricanes; and t-shirts. They are used extensively in the film and special effects industry to simulate explosions in war films. A pneumatic potato cannon // A spud gun refers to one of two things, the classic childs toy which is used to fire small pieces of potato using a small volume of air at low pressure, or a larger pipe-based cannon which uses higher air pressure or combustion of... Special effects (abbreviated SPFX or SFX) are used in the film, television, and entertainment industry to create effects that cannot be achieved by normal means, such as depicting travel to other star systems. ...


Steam engines

Piston valves were used by James Watt in his stationary steam engines, and in many of the engines that followed. James Watt James Watt (19 January 1736 – 19 August 1819) was a Scottish inventor and engineer whose improvements to the steam engine were fundamental to the changes wrought by the Industrial Revolution. ... // The term steam engine may also refer to an entire railroad steam locomotive. ...


In the 19th century, most steam locomotives used slide valves to control the flow of steam into and out of the cylinders. In the 20th century, slide valves were gradually superseded by piston valves, particularly in engines using superheated steam. There were two reasons for this: Union Pacific Big Boy #4012 at work on a cold November 29, 1941 A steam locomotive is a locomotive powered by steam. ... The D Slide Valve was a form of rectilinear slide valve for use in rotative steam engines invented by William Murdoch and patented in 1799. ... Look up cylinder in Wiktionary, the free dictionary. ... General arrangement of a superheater installation in a steam locomotive. ...

  • 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 lubricate slide valves adequately in the presence of superheated steam

The usual locomotive valve gears, e.g. Stephenson valve gear, Walschaert valve gear, and Baker valve gear can be used with either slide valves or piston valves. Where poppet valves are used, a different gear, such as Caprotti valve gear is needed. Lubrication occurs when opposing surfaces are completely separated by a lubricant film. ... Stephenson valve gear is the oldest and simplest standard design of steam locomotive valve gear. ... This article or section does not cite its references or sources. ... Baker valve gear was the main competitor to Walschaert valve gear for steam locomotives in the United States. ... A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. ... The Caprotti valve gear is a type of valve gear invented by the Italian Arturo Caprotti. ...


Brass instruments

Cylindrical piston valves are used to change the pitch in the playing of many brass instruments. Image of a trumpet. ...


Brass instruments can be grouped into four categories, according to the primary means used to change the pitch:

  • Those using piston valves. These include most trumpets, all cornets and almost all tubas, and many others.

There is some overlap between these categories. In addition to its three valves, the trumpet uses a small slide for pitch correction, while the tenorbass and bass trombone both use one or two rotary valves in addition to the slide. The superbone does not fit in to any of the above categories. For Trumpet Winsock, see Winsock. ... Bâ™­ cornet The cornet is a brass instrument that closely resembles the trumpet. ... The tuba is one of the largest of low-brass instruments and is one of the most recent additions to the modern symphony orchestra, first appearing in the mid-19th century, when it largely replaced the ophicleide. ... It has been suggested that this article or section be merged into brass instrument. ... The horn is a brass instrument consisting of tubing wrapped into a coiled form. ... Slide could be related to any of these. ... The trombone is a musical instrument in the brass family. ... A key is a small rectangular button on a musical instrument that is depressed to cause the instrument to create a sound of a particular pitch. ... A serpent is a bass wind instrument with a mouthpiece like a brass instrument but side holes like a woodwind instrument. ... Military bugle in Bâ™­ A French marine bugler at a ceremony in Kuwait City celebrating the success of Operation Desert Storm in 1991 Bugler redirects here. ... The trombone is a musical instrument in the brass family. ... The Superbone is a hybrid trombone. ...


Where piston (or rotary) valves are used, three is the normal minimum (as on a trumpet) and four is not uncommon.


When a piston valve is opened ("pressed" and "pushed down"), each valve changes the pitch by diverting the air stream through additional tubing, thus lengthening the instrument and lowering the harmonic series on which the instrument is vibrating. The following list shows how each valve or combination of valves will affect the pitch from the fundamental. This is true of all brass instruments, however some alternative fingerings are necessary to provide accurate pitch using the fourth and subsequent valves in instruments which have them.

  • second valve - one half step
  • first valve - one whole step
  • first and second valves - one and a half steps. Also achievable by third valve alone but the note will usually be flat
  • second and third valves - two whole steps
  • first and third valves - a perfect fourth, or two and a half steps. Will be sharp unless some means of compensation is used.
  • first, second, and third valves - a tritone, or three whole steps. Will be very sharp unless some means of compensation is used.

A fourth valve is sometimes found on more professional instruments, which creates a perfect fourth, or two and a half steps. Instruments such as the tuba, euphonium, and piccolo trumpet have this valve. Also, on rare instruments, there is a fifth valve, which creates a lower octave of the note, or six tones. These valves are found mostly on tubas and other low brass instruments. More valves than five is ultra rare, but they have been seen, such as on the six-valved cimbasso.


The first piston valve instruments were developed just after the start of the 19th century. The St√∂lzel valve (invented by Heinrich Stoelzel in 1814) was an early variety. In the mid 19th century the Vienna valve was an improved design. However most professional musicians preferred rotary valves for quicker, more reliable action, until better designs of piston valves were mass manufactured in towards the end of the 19th century. Since the early decades of the 19th century, piston valves have been the most common on brass instruments. Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ...


See also

The D Slide Valve was a form of rectilinear slide valve for use in rotative steam engines invented by William Murdoch and patented in 1799. ... A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. ... The sleeve valve is a type of valve for piston engines that has a number of advantages over the more common poppet valve, used in most engines, as well as disadvantages that have precluded its widespread adoption to date. ... External Links Corliss Steam Engine Corliss Steam Engine The Corliss Steam Engine of 1876 ...

External links

  • Early valve designs
  • Why was the valve invented?
  • Elements of Brass Instrument Construction with good discussion of valve types and history
  • Piston valves resources
  • Visual explanations of some types of piston valve

  Results from FactBites:
 
Sanitary fill tube and piston valve assembly for a pouch packaging machine - Patent 5822958 (3151 words)
The piston valve member is actuated by a plunger rod and is guided by a pair of arcuate guide slots formed in the spreader to accurately move the piston valve between open and closed position.
The plunger rod and the piston valve member may include elongated internal passages therein and the piston valve member closely fits into a discharge outlet from the hollow interior of the spreader to accurately control and meter material being fed into a pouch.
The piston valve and plunger mechanism are held in the hollow interior passageway of the fill tube and have a central opening extending through the shaft of the plunger and the piston valve to allow a compressed gas to be used to blow out any product caught in the discharge outlet.
Adjustable piston valve damper - Patent 5647461 (2421 words)
As the piston moves an additional amount of oil substantially equal to the volume of the piston rod entering or exiting the cylinder tube is forced through the piston valving or through a compression valve on the base of the cylinder tube in combination with the piston valving.
The control valve is selectively tuned by adjusting the amount of clearance between the moving valve element and its bore wherein a designed-in clearance is utilized to provide a continuous amount of limited flow through the control valve.
During a compression stroke of the piston assembly 19, the outer perimeter 46 of the annular valve disc 45 deflects upward off the annular rib 36 permitting flow from the flow passages 38 and 39 into the extension chamber 16 from the compression chamber 17.
  More results at FactBites »

 
 

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