Adjustable control valve system for rotating disc filter and method of operating the system

A control system for regulating a vacuum imposed from a disc sector of a rotating disc filter to a central core of the disc filter, the control system and central core being housed in a vacuum box, the system comprising:

• a valve, an actuator, a controller and a pressure sensor,
• the valve comprising a valve body configured to extend around a portion of an outer circumference of the core, the valve body comprising an open end configured for permitting filtrate to pass through the disc sector to the core and into the vacuum box and a closed end configured for preventing flow of filtrate through the disc sector to the core and into the vacuum box with a middle portion disposed therebetween for partially restricting the flow of filtrate through the disc segment to the core, the closed end facing forward in a direction of rotation of the disc filter, the open end facing rearward opposite to direction of rotation of the disc filter,
• the valve body being connected to the actuator for adjusting a position of the closed end of the valve body with respect to the core whereby the actuator can move the valve body forwardly about the core and rearwardly about the core,
• the actuator being in communication with the programmable controller, the controller receiving signals from the pressure sensor, the pressure sensor configured to be disposed inside the vacuum box, the controller being programmed to send a signal to the actuator resulting in rearwardly movement of the valve body when the controller receives a signal from the pressure sensor that a pressure in the vacuum box is above a predetermined level, the controller also being programmed to send a signal to the actuator resulting in forwardly movement of the valve body when the controller receives a signal from the pressure sensor that the pressure in the vacuum box is below a predetermined level.

A method of controlling a vacuum level in a disc filter, the disc filter having a rotating disc with a plurality of disc sectors and a central core with a vacuum across the disc sectors to the core drawing filtrate through the disc sectors and into the core, the rotating disc and core being disposed inside a vacuum box, the method comprising the following steps:

• providing a valve body having an open end for permitting filtrate to pass through the disc segments and the core into the vacuum box and a closed end for preventing flow of filtrate through the disc sector and core,
• establishing a predetermined pressure value for the vacuum box,
• sensing a pressure level in the vacuum box,
• in response to the pressure level in the vacuum box falling below the predetermined value, moving the closed end of the valve body forward in the direction of rotation of the disc,
• in response to the pressure level in the vacuum box exceeding the predetermined value, moving the closed end of the valve body rearward in the direction opposite of rotation of the disc.

A method of controlling a vacuum level in a disc filter, the disc filter having a rotating disc having a plurality of disc sectors mounted to a core that rotates, a pressure drop from the disc sectors to the core drawing filtrate through the disc sectors and into the core, the rotating disc and core being disposed inside a vacuum box, the method comprising the following steps:

• providing a valve body having an open end for permitting filtrate to pass through the disc sectors and core into the vacuum box and a closed end for preventing flow of filtrate through the disc segment and core,
• connecting an actuator to the valve body for adjusting a position of the closed end of the valve body with respect to the core whereby the actuator can move the valve body forwardly about the core in a direction of rotation of the disc filter and rearwardly about the core in a direction opposite to the rotation of the disc filter,
• connecting the actuator to a programmable controller having a memory, the controller receiving signals from a pressure sensor disposed inside the vacuum box, the controller being programmed to send a signal to the actuator resulting in rearwardly movement of the valve body when the controller receives a signal from the pressure sensor that the pressure in the vacuum box is above a predetermined level, the controller also being programmed to send a signal to the actuator resulting in forwardly movement of the valve body when the controller receives a signal from the pressure sensor that the pressure in the vacuum box is below a predetermined level,
• establishing a predetermined pressure value for the vacuum box, recording the predetermined pressure value in the memory of the controller,
• sensing a pressure level in the vacuum box with the pressure sensor,
• sending a signal indicating the pressure level to the controller,
• determining whether the pressure level in the vacuum box is above or below the predetermined pressure value,
• in response to the pressure in the vacuum box falling below the predetermined value, sending a signal from the controller to the actuator to move the valve body forward in the direction of rotation of the disc,
• in response to the pressure in the vacuum box exceeding the predetermined value, sending a signal from the controller to the actuator to move the valve body rearward in the direction opposite of rotation of the disc.