A silt detector

A silt or sludge level detector for use in a liquid environment comprises a body which defines therein a channel that is oriented substantially vertically in use; and a float assembly which is located within the channel, the float assembly defining a silt platform and being arranged to sink when a predetermined weight of silt has accumulated on the silt platform, wherein the body of the detector carries a first sensor element and the float assembly carries a second sensor element; the float assembly has a first configuration in which the first and second sensor elements are in a first spaced relationship with respect to each other and a second configuration in which the first and second sensor contacts are in a second spaced relationship with respect to each other, and wherein when the float assembly sinks, it causes a change in its configuration from the first configuration to the second configuration and the silt detector generates an alarm signal when the float is in its second configuration. The detector body may include one or more openings at a predetermined location between the top and bottom ends, such that when the accumulation of silt in the liquid environment reaches a height that is equal to the or each opening, the silt is then able to enter the body through the or each opening. The first and second sensors may be magnetic sensors.