Pipeline monitoring apparatus

Apparatus for displaying the presence or absence of a change from the normal to abnormal in the condition of a pipeline comprising at least two pairs of vanes mounted around and extending outwardly from a substantially upright shaft, wherein

• (i) at least one pair of vane members is mounted immovably on opposite sides of said shaft, the angle between said vane members being substantially 180.degree.,
• (ii) at least one other pair of vane members is mounted on said shaft, the members of each of said other pair(s) of vanes being mounted on opposite sides of said shaft and being movable relative to said immovably mounted vane members, in such a manner that,
• (a) in a first (normal) position the angle between an immovable vane member and an adjacent relatively movable vane member is not greater than about 15.degree.,
• (b) said movable vane members are adapted to move from said first (normal) position to a second (abnormal) position so that in said second position said angle is substantially zero, and
• (iii) there is means for monitoring the pipeline and a linkage linking the monitoring means to the apparatus in such a manner that when ever an undesirable change in said condition is detected said linkage is activated so as to cause said shaft on which said movable vanes are mounted to rotate sufficiently to carry the movable members from their first position to their second position, said monitoring means being adapted to monitor corrosion current supply to the pipeline and said linkage including a voltage-responsive solenoid linked between a current supply and said shaft.