Feeding method for providing granular material to a hopper

Abstract

A method for feeding granular material into a hopper using a vacuum pump having a suction inlet communicating with the interior of a conduit to feed by vacuum a plurality of receivers connected to the conduit and vertically supported thereby.

The following is claimed: 
     
         1 . A method for feeding granular resin material to a hopper for temporary storage therein preparatory to molding or extruding the granular resin material into plastic parts, comprising:
 a) drawing a vacuum stream upwardly thorough a vertically oriented conduit;   b) laterally connecting at least one receiver to the conduit for vertical support by the conduit, connection of the receiver to the conduit facilitating draw of vacuum in the receiver from the conduit;   c) drawing separate granular resin material/vacuum streams into each of the receivers responsively to vacuum drawn in the receiver from the vertically oriented conduit;   d) downwardly deflecting the granular resin material in the granular material/vacuum stream entering each receiver as drawn by the vacuum;   e) maintaining a valve in the bottom of each receiver closed while continuing draw of vacuum therein, thereby preventing downward flow of granular resin material out of the receiver into a hopper below the receiver;   f) sensing granular resin material weight in the hopper with a load cell;   g) upon weight of granular resin material in the hopper exceeding a preselected value, halting vacuum draw within the receiver by closing the connection between the receiver and the conduit, thereby permitting weight of granular resin material in the receiver to open the flap valve for downward flow of granular resin material out of the receiver and into the hopper.   
     
     
         2 . A method for feeding granular resin material to a hopper for temporary storage therein preparatory to molding or extruding the granular resin material into plastic parts, comprising:
 a) a drawing vacuum stream through an upwardly extending conduit;   b) connecting at least one receiver to the conduit thereby facilitating draw of vacuum in the receiver from the conduit;   c) drawing granular resin material/vacuum streams into each of the receivers responsively to a vacuum in the receiver drawn from the conduit;   d) maintaining a valve in the bottom of each receiver closed while continuing draw of vacuum therein, thereby preventing downward flow of granular resin material out of the receiver into a hopper;   e) continuously sensing weight of granular resin material in the hopper;   f) upon granular resin material weight in the hopper exceeding a preselected value, halting vacuum draw within the receiver and opening the valve for downward flow of material out of the receiver.   
     
     
         3 . A method for feeding granular material to a hopper for temporary storage therein, consisting of:
 a) a drawing vacuum stream upwardly through a conduit;   b) connecting at least one receiver to the conduit, connection of the receiver to the conduit facilitating draw of vacuum in the receiver from the conduit;   c) drawing granular material/vacuum streams into each of the receivers responsively to a vacuum drawn from the conduit;   d) maintaining the bottom of each receiver closed while continuing draw of vacuum therein, thereby preventing downward flow of granular resin material out of the receiver into a hopper below the receiver;   e) sensing granular material weight in the hopper;   f) upon granular material weight in the hopper exceeding a preselected value, halting the vacuum draw within the receiver, thereby permitting the bottom of the receiver to open and the granular material to flow downwardly out of the receiver.   
     
     
         4 . The method of  claim 2  wherein the conduit is vertically oriented. 
     
     
         5 . The method of  claim 4  wherein the conduit is vertical. 
     
     
         6 . The method of  claim 2  wherein the receiver is connected to the conduit laterally and receives vertical support therefrom. 
     
     
         7 . The method of  claim 2  wherein the step of drawing granular material/vacuum streams into the receivers further comprises drawing separate granular material/vacuum streams into the receivers. 
     
     
         8 . The method of  claim 2  wherein the valve maintained closed at the bottom of each receiver is a flap valve. 
     
     
         9 . The method of  claim 2  wherein the step of sensing material weight in the hopper is performed using a load cell. 
     
     
         10 . The method of  claim 2  wherein the step of halting vacuum draw within the receiver comprises closing the connection between the receiver and the conduit. 
     
     
         11 . The method of  claim 3  wherein sensing granular material weight in the hopper is performed continuously. 
     
     
         12 . The method of  claim 3  wherein sensing granular material weight in the hopper is performed intermittently. 
     
     
         13 . The method of  claim 3  further consisting of connecting the receiver laterally to the conduit to receive vertical support therefrom. 
     
     
         14 . The method of  claim 3  wherein the step of drawing granular material/vacuum streams into the receivers further consists of drawing separate granular material/vacuum streams into the receivers. 
     
     
         15 . The method of  claim 3  wherein the step of permitting the bottom of the receiver to open consist of permitting a flap valve to open. 
     
     
         16 . The method of  claim 3  wherein the step of sensing material weight in the hopper further consists of sensing material weight in the hopper by loading a load cell. 
     
     
         17 . The method of  claim 3  wherein the step of halting vacuum draw within the receiver further consists of closing the connection between the receiver and the conduit. 
     
     
         18 . A method for feeding granular material to a hopper for storage therein, comprising:
 a) drawing a vacuum stream upwardly through a conduit;   b) laterally connecting a plurality of receivers to the conduit for support by the conduit, connection of the receivers to the conduit facilitating draw of vacuum in the receivers from the conduit;   c) drawing separate granular material/vacuum streams into each of the receivers, responsively to vacuum drawn in the receiver from the conduit;   d) downwardly deflecting the granular material in the granular material/vacuum stream entering each receiver as drawn by the vacuum;   e) maintaining the bottom of each receiver closed by continuing draw of vacuum thereinto, thereby preventing downward flow of granular material out of the receiver into a hopper below the receiver;   f) sensing granular material weight in each of the hoppers and generating signals proportional thereto;   g) providing the signals to a microprocessor;   h) processing the signals with the microprocessor to determine weight and weight change of granular material in each of the hoppers;   i) upon weight of granular resin material in an individual hopper exceeding a preselected value, halting vacuum draw within the receiver associated with that hopper by closing the connection between the receiver and the conduit, thereby permitting weight of granular material in the receiver to open the receiver bottom for downward flow of granular material out of the receiver and into the hopper;   j) upon a given receiver emptying by downward flow of granular material out of the receiver and into the hopper, resuming vacuum draw in that receiver by opening the vacuum connection between the receiver and the conduit, with the vacuum drawing the receiver bottom closed, thereby resuming flow of granular material into the given receiver.