| 摘要 |
<p>In a method of and apparatus for continual remote monitoring of a local condition, such as the temperature, the pressure, or the volume, of a liquid in a machine in operation and which includes one or more parts wherein liquid is contained and fulfils a function the success of which is contingent upon a variable quantity in a range departure from which is susceptible of interfering with, or at least impairing to a greater or lesser degree, the operation of the machine, light is transmitted by means of optical fibres (13 to 18) from a source (12) to light-responsive indicating means (11) along a trajectory passing through the liquid container, and there is mounted in the container an opaque plate (41) the position or attitude of which changes as the quantity to be monitored of the liquid varies such that a warning indication is given when said liquid quantity departs from said range. The light is preferably split into a plurality of beams passing through the container such that the plate affects each beam in succession as said liquid quantity varies. Preferably, the optical fibres are contained in a bundle outside the container and are divided into separate optical paths on each side of the plate within the container, the plate and the divided optical paths being contained in a closed casing (20) located within the liquid container.</p> |
