Conveying systems

Abstract

A conveying system for conveying a conveyable material from a hopper where the system includes a fluid port located below the hopper outlet and in a vertical flow path into hopper outlet that can be momentarily opened for an on the go release of a charge of compressed air directly upward into the hopper outlet and into the underside of the bridge in the hopper to either disintegrate or unlock the bridged particles from each other thereby causing the bridged material to fall into the hopper outlet and into the conveying system where the material can be transported to a remote location or to remove any material that may be adhering to the wall during an emptying phase.

I claim: 
     
         1 . A conveying system comprising:
 a gravity hopper having a top opening for receiving a conveyable material and a lower hopper outlet for directing the conveyable material therefrom wherein the conveyable material is subject to forming a bridge over the lower hopper outlet thereby preventing flow of the conveyable material from the gravity hopper;   a housing having a material receiving chamber connected to the hopper outlet for carrying the conveyable material away from the lower hopper outlet;   a bridge breaker located vertically below the lower hopper outlet with said bridge breaker having a fluid chamber therein and a top fluid port located in a separator between the material receiving chamber and the fluid chamber in the bridge breaker, said bridge breaker including a slideable piston having a first end momentarily displaceable for opening or closing the top fluid port in the separator; and   a source of pressurized gas located in the fluid chamber for an on demand delivery of a charge of gas upward through the top fluid port when the top fluid port is in an open condition with the charge of gas flowing upward into an underside of a bridge of material over the hopper outlet to disintegrate the bridge of material from below thereby allowing the conveyable material forming the bridge to fall into the material receiving chamber in the conveying system.   
     
     
         2 . The conveying system of  claim 1  wherein the piston comprises a shaft with the first end including a resilient cap for blocking the fluid port when the piston is in a closed condition and a second end larger than the first end with the second end located in a further chamber with the second end having a top face and a bottom face isolated from each other through a slideable seal, said piston responsive to a differential pressure between the top face and the bottom face of the second end for axially displacing the piston from a closed condition to an open condition or from an open condition to a closed condition through changing the differential pressure on opposite faces of the second end. 
     
     
         3 . The conveying system of  claim 1  wherein the gravity hopper has a central axis and the top fluid port is located along the central axis. 
     
     
         4 . The conveying system of  claim 1  including a control station for manually opening and closing the top fluid port in response to a flow condition in the gravity hopper. 
     
     
         5 . The conveying system of  claim 1  including a sensor for detecting the presence of a bridge in the hopper with the sensor connected to a control station to momentarily open
 the top fluid port either automatically or through an operator activation. 
 
     
     
         6 . The conveying system of  claim 1  wherein a stagnation pressure in the bridge breaker P 2  is less than the pressure P 1  above the bridge and the charge of gas comprise a continuous flowing air jet, a variable flowing air jet, a single pulse of air or a repeated pulse of air. 
     
     
         7 . The conveying system of  claim 1  wherein the piston includes a compression spring for normally maintaining the piston in a closed condition in the absence of a control signal from the control station. 
     
     
         8 . A bridge breaker connectable to an underside of a hopper flow outlet comprising:
 a housing having a chamber for receiving and storing a pressurized gas therein;   a separator member having a top fluid port positionable below the hopper flow outlet and in a path of a conveyable material falling into the hopper outlet;   a piston in the housing, said piston movable from a normally closed condition until the top fluid port is an open condition to release a charge of the pressurized gas upward through the top fluid port into an underside of a bridge of conveyable material to disrupt the bridge.   
     
     
         9 . The bridge breaker of  claim 8  including a control station for manually or automatically opening the top fluid port in response to a presence of the bridge of conveyable material and closing the top fluid port before material from the bridge can fall into the top fluid outlet port. 
     
     
         10 . The bridge breaker of  claim 8  wherein a top end of the piston includes a sealing member and a spring normally biasing the piston toward a closed condition for sealingly closing the top fluid port to prevent the conveyable material from falling into the top fluid port. 
     
     
         11 . The bridge breaker of  claim 10  wherein the piston includes a head and a shaft having a first end connected to the sealing member and a second end connected to the head with the shaft vertically slideable within a bearing in the bridge breaker. 
     
     
         12 . The bridge breaker of  claim 11  including a control chamber with the head located in a control chamber in the bridge breaker with the head slideable between a first position on a one end of the control chamber to a second position in the control chamber in response to a pressure differential between a top face of the head and a bottom face of the head. 
     
     
         13 . The bridge breaker of  claim 12  including a port for connecting the control chamber to a source of pressurized air and a compression spring for automatically closing the port in response to a lowering of a differential pressure between the top face of the head and the bottom face of the head. 
     
     
         14 . The bridge breaker of  claim 8  wherein the piston is maintained in an open condition to allow a continuous upward air jet into the hopper outlet with a momentum of an upward force of the continuous upward air jet overcome either by a momentum of the falling conveyable material or the continuous upward air jet having a smaller diameter than the hopper outlet so both the continuous upward air jet and the falling conveyable material can coexist in the same passage. 
     
     
         15 . The method of breaking a bridge in a gravity hopper having a top inlet for receiving a conveyable material and a bottom outlet for gravity discharging the conveyable material therefrom comprising the steps of:
 directing the conveyable material into the gravity hopper until the conveyable material forms a bridge over the hopper outlet;   momentarily directing a charge of pressurized gas upward through a downward facing hopper outlet and into the underside of the bridge to break up the bridge.   
     
     
         16 . The method of  claim 15  including the step of directing the charge of air through an upward facing fluid port in communication with a chamber containing air at a pressure P 2 , which may equal or less than a pressure P 1  above the bridged material. 
     
     
         17 . The method of  claim 16  wherein the fluid port is opened and closed in response to an on demand signal from a control station. 
     
     
         18 . The method of  claim 16  wherein the fluid port is opened and closed in response to sensing of a presence of a bridge in the hopper. 
     
     
         19 . The method of  claim 15  wherein the charge of air is directed vertically upward from the fluid port and the material is prevented from flowing into the fluid port either through rapidly closing the fluid port or maintaining a flow through the fluid port sufficient to deflect conveyable material away from the fluid port. 
     
     
         20 . The method of  claim 19  wherein the charge of air flows from a chamber in a bridge breaker and through a chamber in a conveying system before entering the hopper outlet. 
     
     
         21 . A conveying system comprising:
 a hopper having a hopper outlet for directing a conveyable material downward into the hopper outlet;   a fluid port for directing a pulse of air vertically upward into and through the hopper outlet and into an underside of a bridge of conveyable material over the hopper outlet to disintegrate the bridge of conveyable material from below the bridge of conveyable material.   
     
     
         22 . The conveying system of  claim 21  including a source of pressurized air having a stagnation air pressure greater than an air pressure in the hopper outlet. 
     
     
         23 . The conveying system of  claim 21  wherein an air pressure on a topside of the bridge of conveyable material over the hopper outlet is greater than an air pressure on the underside of the bridge of conveyable material over the hopper outlet. 
     
     
         24 . The conveying system of  claim 21  including an optical sensor for determining if a bridge of conveyable material exists over the hopper outlet. 
     
     
         25 . The conveying system of  claim 21  including a retractable plug for opening and closing the fluid outlet port in response to formation of the bridge of conveyable material over the hopper outlet. 
     
     
         26 . The conveying system of  claim 24  including a compression spring engaging the retractable plug for urging the retractable plug into a closed condition after a portion of the air in an air chamber has been released through the fluid port. 
     
     
         27 . The conveying system of  claim 26  wherein the housing connects to the hopper outlet and the fluid port opens vertically upward into the hopper fluid outlet. 
     
     
         28 . The conveying system of  claim 27  including a pneumatic conveying line connected to the hopper outlet with a source of conveying air connected to the conveying line. 
     
     
         29 . The conveying system of  claim 27  wherein the conveyable material in the hopper has a higher bulk density at a bottom of the hopper than at the top of the hopper. 
     
     
         30 . The method of conveying material from a gravity hopper comprising the steps of;
 directing a conveyable material into a gravity hopper;   gravitationally directing the conveyable material downward into a hopper outlet;   conveying the material away from the hopper outlet; and   directing a stream of air upward into the hopper outlet.   
     
     
         31 . The method of  claim 30  wherein the stream of air is a pulse of air which is directed upward into a bridged region of the conveyable material where a bulk density of the conveyable material is highest. 
     
     
         32 . The method of  claim 31  where the pulse of air travels as a shock wave into the hopper outlet. 
     
     
         33 . The method of  claim 30  of normally maintaining an air pressure on a topside of conveyable material at proximately the same as an air pressure on the underside of the conveyable material through directing air upward into the hopper outlet and opposite to a gravitational flow direction of the conveyable material from the hopper outlet. 
     
     
         34 . The method of  claim 33  wherein a stagnation pressure of the air in a chamber connected to the hopper outlet is maintained at a pressure greater than the air pressure in the hopper outlet. 
     
     
         35 . The method of  claim 34  wherein the pressure of the air in the chamber is maintained a pressure lesser than an air pressure above a bridge of conveyable material but greater than an air pressure in the hopper outlet. 
     
     
         36 . The method of  claim 35  including directing the pulse of air vertically upward into the hopper outlet while there is no downward flow of conveyable material through the fluid outlet. 
     
     
         37 . The method of  claim 36  wherein the pulse of air is released from an air chamber having a stagnation pressure greater than an air pressure in a conveying outlet connected to the fluid outlet. 
     
     
         38 . The method of  claim 37  wherein the stagnation air pressure in the chamber is greater than the air pressure in a conveying chamber below the hopper outlet so the air released into the hopper outlet flows upward into an underside of the region of conveyable material in the hopper. 
     
     
         39 . The method of  claim 30  including the step of directing the air through the hopper outlet during a hopper emptying phase to remove material that may be adhered to the sidewall but not bridged over the hopper outlet. 
     
     
         40 . The method of  claim 30  including the step of maintaining an above atmospheric pressure in the hopper by directing the material into the hopper through a butterfly valve on an inlet of the hopper and directing the air upward through the hopper outlet while the above atmospheric pressure is being maintained in the hopper inlet. 
     
     
         41 . A bridge breaker for a gravity hopper having a downward facing hopper outlet comprising:
 a source of air; and   an upward facing outlet in alignment with the downward facing hopper outlet, said upward facing outlet directing a charge of air from the source of air vertically upward into the downward facing hopper outlet to disrupt or prevent blockage of flow of a conveyable material through the hopper outlet.   
     
     
         42 . The bridge breaker of  claim 41  wherein the charge of air comprise either a continuous flow of air from the upward facing outlet or a series of timed pulses from the upward facing outlet. 
     
     
         43 . A gravity hopper including:
 a downward discharging hopper outlet;   a converging sidewall for directing a conveyable material into the downward discharging outlet; and   an upward facing air outlet in fluid alignment with the downward discharging outlet so that a charge of air emanating from the upward facing air outlet enters the downward discharging hopper outlet from below the hopper outlet and flows upward to encounter the conveyable material in the gravity hopper which may be bridged over the hopper outlet from a location below a bridge of conveyable material to thereby maintain a flow conveyable material through the hopper outlet.   
     
     
         44 . The gravity hopper of  claim 43  including a valve connected to an inlet to the gravity hopper for maintain a pressurized flow of the conveyable material into the gravity hopper. 
     
     
         45 . The gravity hopper of  claim 43  including a control station for opening and closing the air outlet to deliver either a pulse of air, a series of pulses of air or a continual flow of air into the hopper outlet.