Vacuum conveyor system

A conveyor system for transporting a transportable material by means of a fluid for transporting the transportable material from a first conveying line portion to a second conveying line portion, said conveying line portions comprising a plurality of pipes forming a continuous conveying line, said system comprising:

• a conveyor device in fluid connection to said second conveying line portion operative to provide negative air pressure or vacuum through said conveying line;
• a material feeder for having an ambient opening and connected to an inlet end of the first conveying line portion for continuously feeding the transportable material;
• wherein the conveyor device comprises an upper material level sensor, wherein the upper material level sensor is used to monitor an upper material level inside the conveyor device and, via a material level sensor line, to give an upper material level signal to a controller,
• wherein the conveyor device further comprises a lower material level sensor, wherein the lower material level sensor is used to monitor a lower material level inside the conveyor device, and to give a lower material level signal to the controller, and,
• wherein the controller, via a control signal line, is used to transmit a control signal to a valve adjacent a downstream side of the material feeder and adapted to aspirate air being injected into the system via said valve, through which valve the air enters into the conveying line and is mixed with the transportable material in the conveying line so that a mixture of air and transportable material is obtained in the conveying line, and wherein the valve is controlled by a proportional actuator that is controlled by the control signal,
• wherein the controller is adapted to generate the control signal based on the upper and lower material level signals to control the amount of air being injected into the conveying line at the material feeder, and thereby the ratio of air to transportable material in the mixture of air and transportable material in the conveying line.