Thread Specifications - Best Materials

1 B6 PRODUCTS Thread SpecificationsCylinder Valve ThreadsNGT and NPT ThreadsThe NGT (National Gas Taper) Thread is the commonly used valve-to-cylinder con-nection. The male Thread on the valve has about two more threads at the large endthan the NPT in order to provide additional fresh threads if further tightening is nec-essary. Additionally, the standard 3 4" NGT valve inlet provides the greater tightnessat the bottom of the valve by making the valve threads slightly straighter than thestandard taper of 3 4" per foot in NPT connections. In all other respects NPT andNGT threads are ConnectionsCGA OutletsThe CGA (Compressed Gas Association) outlets are standard for usewith various compressed gases.

2 The relation of one of these outlets toanother is fixed so as to minimize undesirable connections. They havebeen so designed to prevent the interchange of connections which mayresult in a "-18 NPT Thread ConnectionThis connection also is used for vapor or liquid withdrawal. It has a 3 8"diameter Thread , and 18 threads per inch, National Pipe Taper 555 CGA 555 is the standard cylinder valve outlet connection for liquid with-drawal of butane and/or propane. Thread specification is .903" 14 NGO LH EXT, which means .903" diameter Thread , 14 threads perinch, National Gas Outlet form, left-hand external 182, or SAE FlareThis connection assures a leak-tight joining of copper tubing to brassparts without need for brazing or silver soldering.

3 The common size usedon LP-Gas valves and fittings is 3 8" SAE (Society of AutomotiveEngineers) flare. Although this connection is referred to as a 3 8", because3 8" OD tubing is used, the Thread actually measures 5 8". The specifica-tions are .625 18 UNF 2A RH EXT, which means .625" diameterthread, 18 threads per inch, Unified Fine Series Class 2 Tolerances, right-hand, external 510 or POLMost widely used in this industry, POL is the common name for the stan-dard CGA 510 connection. Thread specification is .885" 14 NGO LH INT, meaning .885" diameter Thread , 14 threads per inch, National GasOutlet form, left-hand internal Thread . ECII POL outlet connections forLP-Gases conform to this I OutletThis connection is designed to mate with either a 15 16" Female ACME ora Male POL (CGA510).

4 It complies with the ANSI Standard forOutdoor Cooking Appliances and the Standard forContainer Connections. A back check assembly in the outlet is designedto prevent gas flow until a leak free connection is made with an inletadapter. These standards apply to barbecue grill cylinders manufacturedafter October II OutletThis connection is designed to mate with the Quick Connect Male plugthat complies with the ANSI Standard for Outdoor CookingAppliances and the Standard for Container connections. Aback check assembly in the outlet is designed to prevent gas flow until aleak free connection is made with an inlet adapter. These standardsapply to barbecue grill cylinders manufactured after October engagement of allOverall length of all except NGTO verall length of NGTC opper TubingNutCylinderValveOutletCylinderValv eOutletNippleNutCylinder Valve OutletNutNippleInlet ConnectionsBecause of the many Thread forms available on equipment used in the LP-Gasindustry today, the maze of letters, numbers and symbols which make up variousthread Specifications becomes confusing.

5 To help eliminate some of this confu-sion, a brief explanation of some of the more widely used Thread Specifications isshown ConnectBack Check Assembly15 16" Female ACME -Right HandBack Check , CGA 510