AS 2473.2 pdf download – Valves for compressed gas cylinders Part 2: Outlet connections (threaded) and stem (inlet) threads
2.1 VALVE OUTLET CONNECTIONS
The outlet connections specified in this Standard are listed in Table 2.1, and assigned to nominated gases in Table 2.2. The standard valve outlet connections are for use within the pressure range up to 20 000 kPa, based on the pressure conditions of the gas as specified in AS 2030.1. The pressure range applying to the valve outlet connection is intended to protect downstream equipment like pressure regulators from over-pressurized conditions (see Clause 2.2).
In addition, outlet connections for certain compressed gases are specified for use at settled pressures in the range between 20 001 and 31 500 kPa, and between 31 501 and 42 500 kPa. For oxygen, additionally an outlet connection is specified for use between 20 001 and 25 000 kPa, and one for use at settled pressures between 25 001 and 31 500 kPa. For liquefied petroleum gases the standard and limited outlet connections (Types 21, 26 and 41), apply up to 3450 kPa.
For non-toxic, non-flammable refrigerant gases, the standard connection (Type 34) applies up to 5600 kPa. Where the gas is not listed in Table 2.2, or is a gas mixture, the valve outlet connection shall be that given in Table 2.3 for the appropriate classification of gas or gas mixture, and for a pressure range up to 20 000 kPa.
The dimensions of the connections shall be according to Figures 2.1 to 2.28, ensuring the functional interchangeability of all the components of the connection. The leak tightness and integrity of each connection shall conform to Clause 2.2.
1 Following long standing practice from the first editions of AS 2473, the external thread in outlet connections is modified by reduction of major, minor and pitch diameters by 0.10 to 0.15 mm to provide for ease of assembly in service. However, the tolerance band for the major diameter should be decreased to maintain thread engagement at minimum material conditions. This practice is similar to that in CGA V-1.
2 The outlet connections in this Standard are known by their Type number (e.g. Type 10). This designation or its abbreviation (e.g. T10) should be used where outlet connection identification is required on product, for example on connection nuts (see Clause 2.3) or on cylinder valves (see AS 2473.1).
3 Thread designations in Tables 2.1 to 2.3 are from various origins, and care is necessary in their interpretation.
In the designation 0.825-14 NGO-LH-EXT, the value 0.825 refers to the major diameter and 14, to the threads per inch. In the designation G5/8 RH INT, G5/8 is a nominal size and comes from AS 1722.2 and RH (or LH) and EXT or (INT) have been added in this Standard to indicate whether right or left hand threads are specified and whether the thread in the valve is internal or external.
2.2 GAS PRESSURE AND MATERIAL COMPATIBILITY Only regulators, manifolds and ancillary equipment with inlet connections compatible with the valve outlet connections in this standard, rated for the appropriate pressure, compatibility with the relevant gas, and intended application shall be connected to or installed downstream of the valve outlet connection. Each outlet connection provides for screw threads that do not seal, but only hold a nipple against a seat in the valve outlet or against a washer.
For the purpose of this standard, nipples modified to incorporate O-rings or soft tips, and handwheels to permit hand tight connections, shall be considered in compliance if the non-interchangeability specified in the Scope and all other requirements in this Standard are maintained. The leak tightness requirements for the inlet connections of assembled equipment intended to be connected to the valve outlets of this Standard shall be those applying to such equipment and its intended application. All materials used in outlet connections shall be suitable for use with the chemical and physical properties (including pressure) of the intended gases, and of a strength and durability under repeated use, to ensure an adequate service life of the connection. Material specifications are not covered by this Standard.