GB933748A - Vibratory feeder controls - Google Patents

Abstract

933,748. Automatic control systems. CHAIN BELT CO. March 9, 1962 [June 13, 1961], No. 9222/62. Class 38 (4). [Also in Group XXX] The feed rate of material supplied to processing apparatus by a resonant vibratory conveyer is controlled by varying the tuning of the conveyer in dependence upon the load current of the motor driving the apparatus so as to maintain a substantially constant load in the apparatus. As shown, material from a hopper 1 is fed by a vibratory conveyer 2 into processing apparatus 3, e.g. a crusher or mixer, driven by a motor 5 energized from supply leads 6 by way of a control station 7 and leads 8. The vibrator 2 is driven by a variably tuned eccentric weight vibration exciter comprising a motor 11 which has eccentric weights 21 on its shaft and which is mounted in an exciter mass 12 resiliently held between air springs 13, 14 on end plates 15, 16 of a drive housing 17 rigidly attached to the conveyer 2. The amplitude of vibration of the mass 12, and therefore the feed rate of the conveyer, varies according to the inflation pressure of the air springs 13, 14 which are supplied with air through a pipe 60 from a pressure source by way of the control station 7 and a pipe 20. The control station 7 (Fig. II, not shown), includes a first contact-making ammeter responsive to a lower limit of load current in the motor 5 and controlling an electrically actuated air valve which can reduce the inflation pressure of the springs 13, 14 by allowing air to bleed to the atmosphere, and a second ammeter responsive to an upper limit of load current and controlling a second valve which can increase the inflation pressure of the springs 13, 14 by supplying air to them by way of a high-pressure regulator. In operation, the contacts of the high-current ammeter close as the motor 5 reaches its full load operating condition ; high-pressure air is then fed to the springs 13, 14, whereby the vibratory conveyer is de-tuned and the rate of feed reduced. This continues until the contacts of the ammeter open at which point the associated air supply valve closes. If the feed rate is then such that the motor load decreases to the limit determined by the low-current ammeter, the pressure in the air springs is automatically reduced by operation of the valve associated with this ammeter, and the feed rate of the conveyer is increased. The load on the processing apparatus 3 is thus maintained substantially constant.