This paper describes methods for measuring, under working conditions, the charcteristics of commercial screening plant. These methods have been developed by the Road Research Laboratory as part of a programme of research into the problems arising in the production of roadmaking aggregates to meet British Standars specifications. Earlier papers give a description of investigations made under labortory conditions to develop a formual for expressing the efficiency of spparation of a sdcreen and to study the factors affeting this efficiency. The methods described include the measurement of the efficiencies of separation of each of the screens of a commercial plant from the grading and output of the screened cgippings, of amplityde and frequency of vibrtion by means of a stoboscope, of angle of slope by means of a clinometer and of aperture size by means of specially designed taper gauges. The paper also describes how the information can be of direct use to the quarry operator.
Abstract