Pneumatic conveying apparatus automatically operable successively for weight responsive filling, and for activation, discharging, purging, against back pressure, and venting

Claim 1

Material transporting apparatus comprising a pressure vessel including a gas permeable diaphragm bridging the lower part of said vessel above the bottom thereof and dividing it into a material plenum thereabove, and a gas plenum therebelow, a fill valve to admit flowable material through the top of said vessel into said material plenum to upstand from said diaphragm, a compressed gas inlet connection including a gas valve into said gas plenum, a discharge connection from the upper part of said material plenum including a discharge valve disposed in said discharge connection, a purge bypass connecting said material plenum and said discharge connection downstream from said discharge valve, a purge valve disposed in said purge bypass, also a check valve therein downstream of said purge valve and adapted to be urged closed in direction of said purge valve by back pressure acting thereagainst from downstream thereof, a vent discharge from said vessel including a vent valve, means responsive to the weight of material in said vessel, circuitry including said weight responsive means and being automatically operable to open said fill valve, said circuitry then being actuated by said weight responsive means to close said fill valve, then to close said purge valve while opening said gas inlet valve to admit pressurized gas substantially uniformly through said diaphragm and to activate said material to a high state as the pressure rises in excess of a predetermined high pressure to actuate said pressure sensitive control means to open said discharge valve for said material to pass upwardly and onward through said discharge connection, the pressure falling below a predetermined lower pressure to actuate said pressure sensitive control means to close said discharge valve and said gas inlet valve and to open said purge valve, the compressed gas at falling pressure purging through said purge bypass including said purge valve and said check valve, and onwardly through said discharge connection, the pressure continuing falling to a still lower predetermined level to act through said circuitry to close said purge and to open said vent valve, said check valve guarding against back pressure urging gas bearing purge material back up said purge connection, the residual compressed gas purging upwardly through said vent discharge, and the pressure falling to approximately atmospheric whereby to open said fill valve, as aforesaid.

Claim 3

The method of transporting pulverulent material comprising the steps of passing material through an inlet into a closable container onto a gas permeable diaphragm, generating a signal responsive to a predetermined weight of material in said container, closing said material inlet when said signal is generated, closing a bypass conduit from a discharge conduit to the container, and with the container to pass upwardly therethrough to activate the material therein and opening the discharge conduit from the container while closing gas admission, as the pressure in the container drops to predetermined value closing the discharge and opening the bypass conduit to bypass the material to be purged through the bypass and back into the discharge conduit downstream from the container, and as the pressure in the container falls to a still lower predetermined value, employing a check valve in the bypass conduit between bypass conduit closure and discharge conduit to protect against back pressure from the discharge conduit downstream thereof, closing the bypass and opening a vent through which residual pressurized gas and any residual material may be vented as the container pressure returns to substantially atmospheric, then repeating the cycle of steps aforesaid.

Claim 4

The method of transporting pulverulent material comprising the steps of passing material through an inlet into a closable container onto a gas permeable diaphragm, generating a signal responsive to a predetermined weight of material in said container, closing said material inlet when said signal is generated, closing a bypass conduit from a discharge conduit to the container, and with the container to pass upwardly therethrough to activate the material therein and opening the discharge conduit from the container while closing gas admission, as the pressure in the container drops to predetermined value closing the discharge and opening the bypass conduit to bypass the material to be purged through the bypass and back into the discharge conduit downstream from the container, and as the pressure in the container falls to a still lower predetermined value, employing a check valve in the bypass conduit between bypass conduit closure and discharge conduit to protect against back pressure from the discharge conduit downstream thereof, closing the bypass and opening a vent through which residual pressurized gas and any residual material may be vented as the container pressure returns to substantially atmospheric, then repeating the cycle of steps aforesaid.