AS 4624:2005 pdf – Combination controls for gas

AS 4624:2005 pdf – Combination controls for gas.
2.2.5 Accidental displacement of parts
Every part shall be secure against accidental displacement and shall he constructed to maintain a fixed relationship between essential parts under normal and reasonable conditions of handling and usage to ensure continued compliance with this Standard.
2.2.6 Calibration
Means provided for factory calibration shall be factory sealed to prevent accidental shifting after calibration.
2.2.7 Attachment of knobs, handles, movable dials and pointers
Knobs, handles, movable dials and pointers, where supplied, shall be securely attached to
their spindles.
2.2.8 Springs
Springs shall be resistant to corrosion. The ends of a helical spring shall be flat and in a plane perpendicular to the axis of the spring. The coils of a cylindrical helical spring shall not be able to overlap.
2.2.9 Securing of parts
Adhesives shall not be used for securing parts together without additional mechanical fixing means, except for labels.
2.2.10 Sharp edges
Constituent parts shall be free from sharp edges that may cause damage or injury.
2.2.11 Ignition means incorporated in combination control
Where a means of ignition is incorporated in a combination control, the control shall he sufficiently robust to prevent distortion or damage in performing this additional operation.
2.2.12 Means of limiting the travel of manual vahes
The iiicans of limiting the travel of a manual %ale shall be so arranged that it cannot he displaced or damaged.
2.2.13 holes for assembly or mounting
Holes for screws, pins. etc., intended for the assembly of parts or for mounting shall not open into gasways and shall provide a minimum wall thickness of 1 mm from gasways.
2.2.14 Permanent scaling of non-functional holes
Non-functional holes used for manufacture and which form a passage between gasways and the atmosphere shall he permanently sealed by mechanical means.
2.2.15 Self-tapping screws
Self-tapping screws, other than those that form a fully swaged machine type thread, shall not be used to secure together the external joint of a gas-carrying component that may be removed in servicing. The application of thread-forming screws shall be limited to malleable materials and shall not result in deformation or cracking of the component.
2.3 DESIGN
2.3.1Safety functions—‘Fail-safe’type
All safety functions of a combination control shall be of the fail-safe type.2.3.2 Safety device cannot be overridden
No means shall be incorporated to bypass，hold open or partly open any safety functionwhen it should be closed.
2.3.3Accessibility of integral parts
Integral parts that may require adjustment shall be accessible for adjustment.2.3.4 Adjusting devices
Adjusting devices shall be arranged to prevent movement other than manual adjustment.2.3.5 Locking device
The tightening of a locking device shall not alter the setting.2.3.6Design of adjustable regulator
The design of an adjustable regulator shall be such that at no point in the range ofadjustment is it possible for the regulator to be rendered ineffective.