VALVE CONTROL METHOD AND APPARATUS

摘要

Apparatus for controlling the aperture size of a valve in a fluid exhaust line from an individual section of glass forming machine is disclosed. The apparatus controls the aperture size of the valve in response to first and second control signals and comprises a driver connected to the valve for decreasing the aperture of the valve from a preset size to a restricted size by a series of discrete steps and then for increasing the aperture of the valve from the restricted size back to the preset size by a series of discrete steps. The driver is responsive to a directional signal and a series of electrical pulses each actuating a corresponding discrete step to decrease the size of the aperture when the directional signal is applied thereto and to increase the size of the aperture when the directional signal is removed therefrom. The apparatus also comprises a control having a first input responsive to the first control signal which when applied causes the control to provide a directional signal and a predetermined number of electrical pulses to the driver for actuating a predetermined number of discrete steps required to decrease the aperture of the valve from the preset size to the restricted size and a second input responsive to the second control signal which when applied causes the control to remove the directional signal from the driver and provide the predetermined number of electrical pulses to the driver to increase the aperture of the valve back to its preset size.