| 摘要 |
A safety device for ensuring an operator retains an air supply even if a ring mains supply (1) or his individual hose (4) thereto should fail there is an emergency supply (6) from a compressed air bottle which is fed to the operator's face mask (2) via a valve (3). The valve (3) switches from mains/mask to emergency supply/mask when the mains pressure falls below the emergency supply pressure. <IMAGE> |
