ISO 8434-3:2005,Metallic tube connections for fluid power and general use — Part 3: O-ring face seal connectors.ISO 8434-3:2005 pdf free download.
In fluid power systems, power is transmitted and controlled through a fluid (liquid or gas) under pressure within an enclosed circuit. In general applications, a fluid may be conveyed under pressure.
Components may be connected through their ports by connections (connectors) and conductors (tubes and hoses). Tubes are rigid conductors; hoses are flexible conductors.
This part of ISO 8434 is based on the USA standard ANSI/SAE J1453. The threads for the O-ring face seal connection are unified inch threads to ISO 263. The inch threads were not changed to metric threads to ISO 261 to allow connectors complying with this standard to be used in existing applications without requiring a change to tube or hose assemblies. Also, the thread-to-nut overtorque and seal performance have been extensively tested; to change to metric threads would require an extensive test program at considerable cost without providing any functional improvement. The threads are integral to themselves, connectors of this type match only to themselves, and other than having metric threads, no value in changing could be found. Major international companies that have used these connectors have adopted the design without noting any problems. All wrench flats are dimensioned to be used with ISO standard metric wrenches.
This part of ISO 8434 specifies the general and dimensional requirements for the design and performance of O-ring face seal connectors made of steel for tube outside diameters or hose inside diameters of 6 mm through 38 mm, inclusive. These connectors are for use in fluid power and general applications where elastomeric seals can be used to prevent fluid leakage, including leakage caused by variations in assembly procedures. They are intended for the connection of tubes and hose fittings to ports in accordance with ISO 6149-1. (See ISO 12151-1 for related hose fitting specification.)
These connectors provide leakproof, full-flow connections in hydraulic systems operating from a vacuum of 6,5 kPa [0,065 bar 3)] absolute pressure to the working pressures shown in Table 1. Because many factors influence the pressure at which a system performs satisfactorily, these values shall not be understood as guaranteed minimums. For every application, it is recommended that sufficient testing be conducted and reviewed by both the user and manufacturer to ensure that required performance levels are met.
Normative references
ISO 3304, Plain end seamless precision steel tubes — Technical conditions for delivery;
ISO 3305, Plain end welded precision steel tubes — Technical conditions for delivery;
ISO 3601-3:—4), Fluid systems — Sealing devices — O-rings — Part 3: Quality acceptance criteria;
ISO 4759-1, Tolerances for fasteners — Part 1: Bolts, screws, studs and nuts — Product grades A, B and C;
Bodies shall be manufactured from carbon steel that will provide the minimurn pressure/temperature requirements specified in Clause 5, when tested in accordance with Clause 15.They shall have characteristics that make them suitable for use with the fluid to be conveyed and that will provide an effective joint Weld-on sleeves shall be made of materials classified as suitable for welding.