Method and apparatus for the pneumatic conveying of bulk material

A method for the pneumatic conveying of bulk material comprising the steps of

• a. introducing a conveyor gas into a conveyor conduit;
• b. introducing material to be conveyed into the conveyor conduit for conveying by the conveyor gas;
• c. passing gas through a by-pass conduit which has communications with the conveyor at a plurality of spaced positions, the pressure distribution in the by-pass conduit being substantially adapted to the pressure distribution which occurs in normal operation in the conveyor conduit;
• d. positioning a plurality of shut-off means in spaced relation along said by-pass conduit thereby to divide said by-pass conduit into a series of sections each of which is between adjacent shut-off means, said shut-off means serving only to permit or shut off flow through said by-pass conduit and not serving to communicate flow between said by-pass conduit and said conveyor conduit;
• e. positioning a plurality of flow transfer valves in each section, each of said valves being adapted to permit the flow of gas from said by-pass conduit into said conveyor conduit when the pressure difference between the by-pass conduit and the conveyor conduit exceeds a preselected threshold value due to a pressure drop in the conveyor conduit downstream of a gas flowimpeding accumulation of material in the conveyor conduit,
• whereby gas is transferred from the by-pass conduit into the conveyor conduit simultaneously by way of all of said flow transfer valves in such sections which are disposed between said accumulation of material and the next following downstream shut-off means.