Programmable alarm system for marine loading arms

Abstract

A system for sensing the positon in space of the outer end of an articulated fluid loading arm while it is connected to a marine tanker or other transport vessel, and for sounding an alarm if the arm's operating envelope is exceeded. The sensing system includes means for determining various angles representative of the orientation of the booms or limbs of the arm, and a microprocessor for using these angles to compute the spatial position of the arm's outboard end. The boundaries between the safe and unsafe areas of operation of the arm are stored in a digital memory and compared with the actual position of the arm. The boundaries which define the safe areas can be any desired shape, and the shape can be readily changed by storing a new set of boundary values in the digital memory. If desired, the location of the boundaries can be made to depend upon the velocity of the arm as it is being maneuvered. When the outboard end of the arm moves into an unsafe area an alarm sounds, and the system is shut down if the arm moves a predetermined distance farther into the unsafe area.