Since many factors should be considered, temperature, pressure, percent of concentration, etc. Remember, bray carries epdm, bunan, and teflon molded discstems, thus one should select a teflon disc stem and a teflon seat for this application. It can withstand pressures of up to 6000 psi dependent on valve size and a temperature range of. The valve seat is a critical component of an engine in that if it is improperly positioned, oriented, or formed during manufacture, valve leakage will occur which will adversely affect the. Material description color reinforced teflon rptfe reinforced polytetrafluoroethylene rptfe is the standard seat used in most noncavity truflo ball valves.
Chapter 4 describes digital valve controllers, analog positioners, boosters, and other control valve accessories. Although valve shell material selection is very important, other components must receive the same care when it comes to materials selection. Please refer to our ball valve catalogs, e201, e204 or e205. The single port valves are used where the shut off requirements are stringent. Durable metal seat design and material also provides fully guaranteed throttling service performance, which makes kitz metal seated ball valves function as a reliable control valve. Ball valve seat selection guide triad process equipment.
The key specifications for cast steel valves body materials are astm a216 wca, wcb, wcc, astm a352 lcblcc lowtemperature, and astm. Engineering bulletin ball valve seat and seal materials. On color service aplic tion ptfe virgin polytetrafluoroethylene45 c160 c 49 f320 f 70 bar psi 140 bar 2000 psi 140 bar 2000 psi 140 bar 2000 psi 140 bar 2000 psi. If we leave mechanical and dimensional considerations aside, a valve seat material with greater thermal conductivity will transfer heat from the.
Bunan bunan hycar or nitrile is an all purpose polymer with good resistance to air, water, solvents, oil and hydraulic fluids, alcohols, glycols and propane and butane. Choosing the right seat material is the most challenging. On older engines with cast iron cylinder heads the valve seat was cut straight into the iron. Ball valve seat seal selection guide standard ball valve seat selections ball valve seat guide for steam use material technical description typical colour approx. Assured automation offers a variety of butterfly valves for a wide range of industrial applications. I have an onan p220 gas engine in which the intake valve seat insert on the one cylinder has become loose in its bore. In these valves metal to metal seating surface or soft seating with ptfe or other material is used to make the seat. A valve seat material bray a subsidiary of bray international. Valve seats copper bronze alloy valve seat material.
Seat material guide sure seal seat chart is to be used only as a guide in selec ng the most sa sfactory combina on of elastomers for resistance to various chemical solu ons. The most economical bray coating material will be noted with an asterisk. This bulletin provides an overview of these valve seat mate. Various seat materials are available at kitz to meet these applications. Applications valve seat seal materials global supply line. Flowtek offers peek in two grades, unfilled and filled. Ball valve seat materials and applications virgin ptfepolytetrafluoroethylene ptfe or tfe teflon is a fluorocarbon based polymer and typically is the most chemically resistant of all plastics while retaining excellent thermal and electrical insulation properties.
Typically we hard face a stainless steel seat with stellite then lap the ball to the seat for tight shutoff. In these valves metal to metal seating surface or soft seating with ptfe or other material is. When selecting seats, always consult the pressuretemperature and corrosion resistant charts. C a352lc1 a352lcb a352lcc low temperature alloy steel. In a fourstroke race engine, the valve seats play an important part in the mechanical reliability and heat management of the valves. Bunan hycar or nitrile bunan is a generalpurpose polymer which has good resistance to oil, water, solvents and hydraulic. Chapter 2 develops the vital topic of control valve performance. Butterfly valve seat selection guide assured automation. Its chemical compatibility is excellent for almost all applications. The pt ratings of ball valves are limited by the body materials as well as the seat materials. Various forms of this valve seat are available angle, globe, forged, bar stock, and split constructions. This bulletin releases a generalized chart showing ball valve seat material properties for various seat materials currently offered in milwaukee valve company commercial and industrial valve.
Metso sealing technology provides for applications from 320 to 500f 198 to 260c and pressures from vacuum to 1480 psi 102 bar. Xtreme seat materials unique design, with low permeability and controlled crystallinity, produces a valve seat with less. Sure, there may be two, three, four or more of them in the cylinder head, but unless you have xray eyes, one alloy looks pretty much the same as another. Fillers including graphite enable this seat material to have a better cycle life than other filled or reinforced tfe seats. These properties make it a superb seat choice for elevated pressure coupled with elevated temperature. Control valve and regulator section notes that fci 702 has been intended to apply to control valve seat leakage. The valve guide enables valve movement and stroke as a consequence of acceleration by camshaft and keeps the valve in the center of. Epdm is a standard seat material offered in bray resilientseated butterfly valves. The packing operates on an interference fit with the body and therefore will seal in pressure and vacuum. Stellite offers a good combination of relative hardness and corrosion resistance. Torque adder delrin pom this seat is very rigid and does not undergo cold flow. No application carbon steel cs cmnfe a105n k03504 a216wcb c22.
A valve s trim performance is determined by the disk and seat interface and the relation of the disk position to the seat. In addition the guiding, the seat material, the actuator thrust, the pressure drop and the type of fluid all play part in how well particular control valves shuts off. Note this chart is meant to be used as a guide only and is based on average conditions. The valve body, bonnet, packing, et cetera that also come in contact with the flow medium are not considered valve trim. This seating material has excellent chemical resistance and low coefficient of friction. Specifically formulated to provide enhanced performance across a wide temperature and pressure range, devlon vapi is now widely specified by valve manufacturers and has rapidly gained approval for use by major oil and gas producers. Additional seat materials molybdenum disulfide coated. Integral guide inside body keeps wedge selfcentered during valve opening and closing.
A forged valve body is produced by forging and machining solid steel. Valve material selection chart material selection guide. Devlon vapi thermoplastic valve seats james walker. Pt rating charts introduced in this literature show only ball seat ratings. The importance of coatings to todays valves should not be overlooked, of course. Ball valve seat rating chart mvtb01001, page 1 of 2 february 7, 2001 this bulletin releases a generalized chart showing ball valve seat material pressure ratings versus temperature for various seat materials currently offered in milwaukee valve company commercial and industrial valve products, as presented on sheet 2 of this bulletin. Ball valves, general purpose and special application 60. Learn about the key astm material specifications for valves. So im now thinking about making my own seats but am wondering what material to use. It displays good compressions, tensile strength and abrasion resistance. Engineering bulletin ball valve seat and seal materials seat materials applications t virgin ptfe polytetrafluoroethylene is a fluorocarbonbased polymer. The valve head seals off the inlet or outlet duct of the closed valve from the valve seat in the cylinder head.
The combination of ceramic tool steel made of tungsten carbide and the large amounts of permanently embedded lubricants is especially suited for dry combustion occurring in. Flexible wedge is able to compensate for seat surface distortion and body deformation caused by piping stress. We have a broad range of valve seat materials to suit your application, have a look at the table below or call us on 01992 515880 to talk to us in more depth about your project. These parts include valve seat s, disc, glands, spacers, guides, bushings, and internal springs. Valve trim is loosely defined as the closure elements in a valve, including disc, ball and seats, as well as the stem or spindle, all of which are exposed to. Gate valve material list gate valve 10 11 l1 h l w class 150 class 300. This would need to be done by someone else, which is not difficult to arrange but i had not planned on the cost of the valve seat material. Modentic valve seat material selection guide valve seat material selection guide. Diesel, gasoline petrol powder metal and cast valve seats inserts.
In general, the valve seat will conduct much of the heat away from the valve head during the time the valve is shut. Sep 10, 2015 various forms of this valve seat are available angle, globe, forged, bar stock, and split constructions. Size type end drilling body disc shaft seat operator example. Small engines, light vehicle, heavyduty, industrial. For a modulating butterfly valve, for example, the valve body may be considered a nonimpingement site while the disk, portions of the seat and retainer, stem, etc would be considered subject to impingement. Valve seats should be replaced during each and every rebuild in order to insure a proper valvetoseat contact. It is the most universal and economical of seat materials offered by bray. Understanding valve design and alloys by doug kaufman to the naked eye, a valve is a valve is a valve.
Material group common name material type forging spec uns casting spec. Polytetrafluoroethylene is a fluorocarbonbased polymer. Stainless steel impregnated teflon seats combine the strength of metal with the lubricity of ptfe. These parameters are guidelines, and customers are responsible for materials of construction being compatible with their valve application. Integral seat d these trim numbers are not included in api 600. The valve seat in an internal combustion gasoline or diesel engine is the surface against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed. Valves feature a diverse range of additional equipment, depending on the engine load and type of use, such as hardening and armouring for the valve heads and valve stem faces. Chapter 5 is a comprehensive guide to selecting the best control valve for an. For service with severe flashing, hydraulic shock, high temperature or abrasive media. Ptfe is noncontaminating and accepted by fda for use in food services. Thus use of a stainless steel body may be permissible but a more burn resistant. Torque adders to the standard seats indicated in catalog page d delrin this seat is very rigid and does not undergo cold. These engines generally liked leaded fuel and higher octanes to keep temperatures down and the lead again helps reduce preignition which can result in t.
Seat code material description color 578 virgin tfe ptfe virgin tfe is a common seat material used in many ball valves. Keystone series 36 and 37 klok high performance butterfly valves adjustable shaft packaging polymer seated valves the kloks unique shaft packing is composed of 3 rings of braided ptfe rope between one ptfe vring at the top and bottom. You can also find individual datasheets in our materials section. Performance engine valve technology materials and designs. Carbon filled tfe carbon filled tfe is an excellent seat material for steam applications as well as high efficiency oilbased thermal fluids. If line isolation andor absolute tight shutoff is a normal expectation of the valve application, the fci control valve and regulator sections recommend specifying another standard, such as api 598, valve test and inspection. New valve seats should be a relatively soft material, such as bronze or nodular iron heat treated to rockwell rc32 or less.
It can withstand pressures of up to 6000 psi dependent on valve size and a temperature range of 70f to 180f. The width of the contact zone valve face to valve seat should be at least 1mm. What is the material of engine valve seats and valves. Use a gear operator or valve actuator to fix the valve position when used for throttling service. Milwaukee valve company technical bulletin engineering. Please consult at controls for seat material selection for your unique applications. A cast valve body is manufactured by pouring liquid metals into molds and is common for valves above 2 inches in diameter. Materials of construction component valve body materials stainless steel carbon steel brass material gradeastm specification 1 stem nut 316 ss lowalloy steel grade 7a194. Double seated control valves have very poor shut off capabilities. Standard seat selections seat code material technical description color approx. Delrin can withstand pressures of up to 6000 psi dependent on valve size and a temperature. The valve seat is a critical component of an engine in that if it is improperly positioned, oriented, or formed during manufacture, valve.
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