US 4,176,749 A · Materials separation

Abstract

A wash box for separating materials produced in, for example, a mining operation, into fractions of different densities. The machine is divided vertically into compartments, including at least one stratification compartment and at least one reject compartment, the raw material being delivered onto the grid, the level of water in the compartments being higher than the grid. Vertical pulsations are applied to the water in the compartments, causing the water to travel through the perforations of the grid, to stratify the material on the grid, while movement of the water through the wash box tends to carry the lighter fraction from the wash box. The pressure which pertains in the stratification compartment is continually monitored, such as by the use of a beam, emitted into a stand pipe connected to the stratification compartment, and which is reflected by the surface of the water in the stand pipe, the time taken for the beam to travel from the emitter to a receiver being used to produce an output signal, dependent upon the pressure pertaining in the stratification compartment. This continual monitoring is advantageously used to control the pulsations applied to the adjacent reject compartment, controlling the rate at which reject material falls over the edge of the grid, but may be used to advantage in the general control of operation of the wash box. Alternatively or in addition, separate conveyor means are provided, at differing vertical levels, for removing the reject materials of smaller size, which pass through the perforations of the grid, and the reject materials of larger size, which pass over the edge of the grid. Such an arrangement is particularly advantageous where the wash box is a compound wash box.

Claims21

Dependent claims

A method of controlling the operation of a wash box in the form of a vessel divided vertically into water containing compartments and having a perforate grid plate extending across upper parts of the compartments, means being associated with the vessel which is operative to apply pulsations to the water in the compartments to produce a cyclic rise and fall of liquid in the compartments, said method involving the steps of:

(a) transmitting wave energy towards the surface of the liquid in one of said compartments;
(b) receiving a reflected signal therefrom;
(c) comparing a function of the transmitted signal with a function of the received signal to derive a comparative value;
(d) acting arithmetically upon successive comparative values to derive an output signal;
and
(e) utilizing said output signal to control the operation of the wash box.

3 more elements

In a wash box comprising a vessel divided vertically into water-containing compartments, including at least one stratification compartment and a reject compartment, a perforate grid plate extending across upper parts of the compartments, the wash box comprising first pulsation means associated with the stratification compartment and which is operative to produce a cyclic rise and fall in the water in the stratification compartment and a second pulsation means associated with the reject compartment and which is operative to produce a cyclic rise and fall in the water in said reject compartment, the improvement wherein the wash box comprises:

(a) transmission means associated with the vessel to transmit signals towards the surface of the water in the stratification compartment;
(b) receiving means associated with a vessel to receive signals reflected from the surface of the water in the stratification compartment;
(c) an output device connected to the transmission means and to the receiving means and which is operative to measure the period of time between the transmission of each signal and reception of the reflected signal, and to operate arithmetically on the measured periods of time to produce an output signal which is dependent upon the change in the mean level of water in the stratification compartment;
and
(d) control mechanism associated with the second pulsation means and which is operative to vary the action of the pulsations applied to the reject compartment in accordance with the output signal.

2 more elements

Dependencies are inferred from the claim text.

Materials separation

Life of this patent

Materials separation

Life of this patent

Abstract

Claims21