Device for and method of controlling the level in appropriate containers

Abstract

A device for controlling the level in a container of a liquid which will emit infra-red rays and particularly molten metal is described. The device comprises a housing, at least one longitudinal window at one end of the housing and arranged so that when in use it will overlook an edge of a container containing the liquid, the level of which is to be controlled; and at least one photo-element for sending out an electrical signal through said window to said liquid; at least one second window which is substantially punctiform and which overlooks a substantially constant portion of the liquid in the container and within the vertical field of adjustment; and a second photo-element in cooperation with the second window for sending out a pilot signal, and circuitry to correct the signal indicating the liquid level of the container by means of the pilot signal and for amplifying and comparing the signal coming from the correction circuit. The device when in use is positioned so that the optical axis thereof is at an angle to a line vertical to the liquid level in the container, whereby the longitudinal window cooperates with the edge of the liquid containing container, the level of which is to be measured and controlled. Additional windows and photo-electric elements can be utilized to accomplish ancillary functions, including adjusting the speed of withdrawal of liquid from the container and/or to adjust the quantity of liquid in the container as, for example, in a continuous casting ingot mold. The device is simple in construction, easily operated, and accurate.