Detection of fruit and vegetables conveyed by water - by acoustic or electromagnetic energy reflection esp. at two positions

摘要

Objects floating in and/or transported in liquids, esp. water, are detected by sonic or electromagnetic waves emitted into the water and reflected back from the object to a receiver; the reflection pattern in the case of acoustic signals and the intensity of reflected or transmitted electromagnetic radiation are measured. Pref. two emitters and two associated receivers are used; the readings from the receiver pass to a comparator, which emits a signal if fruit or other articles are present opposite one of the receivers. Typically, the arrangement of the flow channel is such that the objects cannot pass before the second emitter and receiver. Used esp. for modern plants which transport vegetables and fruit by water and where it is necessary to detect the presence or absence of the fruit or vegetables. The appts. operates without physical contact devices. In particular, the min. detection period may be utilised where it is desired only to measure fairly large accumulations of fruit and not individual fruits.