Apparatus for the conveyance of cohesive particulate material

Claim 3

The method according to claim 1 characterized in that the point near the outlet orifice of the hopper at which gas under pressure is introduced, is situated an amount above the outlet orifice between one-third and one-sixth of the height above the outlet orifice of the top of the slanted walls of the hopper.

Claim 4

The method according to claim 1 in which the average rate of flow of the gas introduced intermittently with the delivery pipe is of the order of one-fifth of the average transport rate of the particulate material through the delivery pipe.

Claim 5

The method according to claim 1 characterized in that the gas intermittently introduced into the delivery pipe is delivered with an on-off time ratio of approximately 1:1 and a cycle frequency of 1 cycle per second.

Claim 6

The method according to claim 1 characterized in that the flow rate of the gas under pressure introduced into the space above the surface of the particulate material in the hopper is regulated so that it is equal to the flow rate of the material from the hopper.

Claim 7

The method according to claim 1 in which the flow rate of the gas introduced into the hopper at a point near the outlet orifice is not greater than one-fourth of the rate of transport of the particular material along the delivery pipe.

Claim 8

Apparatus for conveying cohesive particulate materials from storage means to a remote delivery point characterized by a mass flow hopper, as the storage means, having an exit orifice too small to obviate bridging of the material when propelled by gravity alone, a delivery pipe connected to the said exit orifice means and leading to the delivery point, means for applying gas under pressure to the surface of the material in the hopper with a flow rate equal to the transport rate of the material from the hopper, means for introducing gas under pressure into the hopper at a point neat to the outlet orifice and for regulating the flow rate so that it does not exceed one-fourth of the transport rate of the material from the hopper and means for intermittently introducing pressurized gas into the delivery pipe at a point near to but spaced away from the junction thereof with the outlet orifice of the hopper whereby the particulate material in the delivery pipe is divided into discrete plugs separated by gas-filled spaces.

Claim 9

Apparatus for conveying cohesive particulate materials from storage means to a remote delivery point characterized by a mass flow hopper, as the storage means, having an exit orifice too small to obviate bridging of the material when propelled by gravity alone, a delivery pipe connected to the said exit orifice means and leading to the delivery point, means for applying gas under pressure to the surface of the material in the hopper with a flow rate equal to the transport rate of the material from the hopper, means for introducing gas under pressure into the hopper at a point neat to the outlet orifice and for regulating the flow rate so that it does not exceed one-fourth of the transport rate of the material from the hopper and means for intermittently introducing pressurized gas into the delivery pipe at a point near to but spaced away from the junction thereof with the outlet orifice of the hopper whereby the particulate material in the delivery pipe is divided into discrete plugs separated by gas-filled spaces.

Claim 10

Apparatus according to claim 7 in which the hopper has a lower part with walls slanting inwardly towards the outlet orifice characterized in that the said point near the outlet orifice for introduction of gas under pressure into the hopper, is spaced from the outlet orifice by an amount between one-third and one-sixth of the overall height of the said lower part of the hopper.

Claim 11

Apparatus according to claim 7 characterized in that pressurized gas is intermittently introduced into the delivery pipe through a valve which is controlled to open and shut cyclically by an oscillator.

Claim 12

Apparatus according to claim 9 characterized in that the oscillator is an electronic oscillator.

Claim 13

Apparatus according to claim 7 characterized in that the delivery pipe has a short length of its wall in the form of a gas-permeable sleeve with a jacket surrounding the said short length of pipe wall and with an air entry port in the jacket coupled to a source of intermittent pulses of pressurized gas.

Claim 14

Apparatus for conveying cohesive particulate materials from storage means to a remote delivery point, characterized by: a mass flow hopper as the storage means; an exit aperture for the mass flow hopper which is too small to obviate bridging of the particulate material when propelled by gravity alone; a delivery pipe connected to the said exit orifice and leading to a delivery point; means for applying gas under pressure to the surface of the material in the hopper; means for regulating the volume flow rate of the said gas applied to the surface of the material in the hopper so that it is substantially equal to the volume flow rate of material down the hopper; means for introducing gas under pressure into the hopper at a point near to the outlet orifice; means for regulating the volume flow rate of the said gas introduced at the point near to the hopper outlet orifice so that it does not exceed one-fourth of the volume flow rate of material down the hopper; air introduction means comprising gas introduction paths distributed around the circumference of the delivery pipe at a location along such pipe which is near to but spaced away from the junction thereof with the hopper outlet orifice such paths communicating with the interior of the pipe; means for intermittently supplying gas under pressure to the gas introduction paths whereby the particulate material in the delivery pipe is divided into discrete plugs separated by gas-filled spaces; and means for regulating the average volume flow rate of the gas supplied to the said introduction paths so that it is of the order of one-fifth of the average volume flow rate of particulate material through the delivery pipe.

Claim 15

Apparatus for conveying cohesive particulate materials from storage means to a remote delivery point, characterized by: a mass flow hopper as the storage means; an exit aperture for the mass flow hopper which is too small to obviate bridging of the particulate material when propelled by gravity alone; a delivery pipe connected to the said exit orifice and leading to a delivery point; means for applying gas under pressure to the surface of the material in the hopper; means for regulating the volume flow rate of the said gas applied to the surface of the material in the hopper so that it is substantially equal to the volume flow rate of material down the hopper; means for introducing gas under pressure into the hopper at a point near to the outlet orifice; means for regulating the volume flow rate of the said gas introduced at the point near to the hopper outlet orifice so that it does not exceed one-fourth of the volume flow rate of material down the hopper; air introduction means comprising gas introduction paths distributed around the circumference of the delivery pipe at a location along such pipe which is near to but spaced away from the junction thereof with the hopper outlet orifice such paths communicating with the interior of the pipe; means for intermittently supplying gas under pressure to the gas introduction paths whereby the particulate material in the delivery pipe is divided into discrete plugs separated by gas-filled spaces; and means for regulating the average volume flow rate of the gas supplied to the said introduction paths so that it is of the order of one-fifth of the average volume flow rate of particulate material through the delivery pipe.