副本(1)[www.staffempire.com]-BS 1212-1-1990 Float operated valves. Specification for piston type float operated valves.pdfVIP免费

BS1212:Part1:1990UDC621.646.618:621.646.2-314.1:669.35’50BritishStandardsInstitution.NopartofthispublicationmaybephotocopiedorotherwisereproducedwithoutthepriorpermissioninwritingofBSIBritishStandardFloatoperatedvalvesPart1.Specificationforpistontypefloatoperatedvalves(copperalloybody)(excludingfloats)RobinetsaflotteurPartie1.Robinetsaflotteurdetypepiston(corpsenalliagedecuivre)(aI’exclusiondesflotteurs)-SpecificationsSchwimmerventiIeTeil1.Kolbenschwimmerventile(mitGehauseausKupfer)(ausgenommenSchwimmer)BritishStandardsInstitutionLicensedcopy:PONTYPRIDDCOLLEGE,13/02/2008,UncontrolledCopy,©BSIBS1212:Part1:1990ForewordThisPartofBS1212hasbeenpreparedunderthedirectionoftheBuildingServicesStandardsCommitteeandspecifiesrequirementsforpistontypefloatoperatedvalves(exclud-ingfloats).ItsupersedesBS1212:Part1:1953,whichiswithdrawn.ThenewfeaturesinthisPartofBS1212includethefollowing:(a)thepossibleproductionofcertaincomponentsfromplasticsmaterials;(b)anextensionoftherangeofsizesofplasticsseats;(c)aseatnumberingsystem;(d)abottomentryinletconnectionanditsassociatedinletelbow,withadjustablestay;(e)arecognitionofthegreaterliftingeffortofplasticsfloatsovercopperfloatsofequivalentsize;(f)thesupplyofsize3/8andsize'12leverswithadownturnportionfittedwithafloatadjusterandthumbscrew;(9)afurthermethodofproductionfortwopiecelevers(h)atestforplasticsbacknutstrength,inlinewithBS1212:Part3;(j)atestforplasticslocknutstrength;(k)arecognitionofcurrentmanufacturingpracticebydeletionofreferencetotheuseofagatetippedseats.DuetothefactthatvalvescoveredbythisPartofBS1212donotprovidetheappropriatebacksiphonageprotectionrequiredbytheWaterByelaws,itisrecommendedinthecaseofnominalsizevalvesthatavalvecoveredbyoneoftheotherPartsofBS1212beusedforapplicationswherebacksiphonageprotectionisrequired.Alternatively,avalvecoveredbyBS1212:Part1canbeusedinthesecasesifasuitableprotectivedeviceisconnectedtothefeedpipertothevalve.Fornominalsize%andabove,suchadeviceshouldbeusedwheneverbacksiphonageprotectionisrequir...