US3831643A - Bag filling machine having door-type inlet valve - Google Patents

Abstract

The inlet valve is at the top of the pressure chamber, and has a casing, a door-type valve pivotally mounted within the casing which abuts against a doorstop baffle edge. The door valve includes a doorplate having Teflon bar wiping seals along two side edges and the top or hinge edge. The baffle slopes to provide a free space into which the top air is fed. The air blows between the doorplate and baffle edge as the door is in its almost closed position to sweep the abutting edges clear of particles. A time delay retards the door closing movement with respect to the opening of top air supply. Weighing mechanism controls the door opening movement. A second baffle provides an expansion chamber above the first baffle to accommodate material displaced by the door movement, and a porous wall permits escape of the air sweep air.

Description

United States Patent [191 Lau [ Aug. 27, 1974 BAG FILLING MACHINE HAVING DOOR-TYPE INLET VALVE [75] Inventor: Erwin M. Lau, Bolton, 111.

[73] Assignee: Black Products Co., Chicago, Ill. [22] Filed: May 21, 1973 [21] Appl. No.: 362,258

[52] US. Cl. 141/68, 141/83, l4l/125 177/118, 251/298 [51] Int. Cl B65b 1/18 [58] Field of Search 141/11, 67, 68, 125, 83; 177/118, 256; 277/27, 165; 251/298 [56] References Cited UNITED STATES PATENTS 2,782,962 2/1957 Mercer 251/298 3,112,776 12/1963 Riley 141/67 Primary Examiner-Houston S. Bell, Jr. Attorney, Agent, or Firm-Bayard Jones v [57] ABSTRACT The inlet valve is at the top of the pressure chamber,

and has a casing, a door-type valve pivotally mounted within the casing which abuts against a doorstop baffle edge. The door valve includes a doorplate having Teflon bar wiping seals along two side edges and the top or hinge edge. The baffle slopes to provide a free space into which the top air is fed. The air blows between the doorplate and baffle edge as the door is in its almost closed position to sweep the abutting edges clear of particles. A time delay retards the door closing movement with respect to the opening of top air supply. Weighing mechanism controls the door opening movement. A second baffle provides an expansion chamber above the first baffle to accommodate material displaced by the door movement, and a porous wall permits escape of the air sweep air.

' 1 1 Claims, 10 Drawing Figures 'suzn NF 5 PATENTEU m2? I974 I LEE 3 :i 40

BAG FILLING MACHINE HAVING DOOR-TYPE INLET VALVE This invention relates to bag filling machines in which a bag is suspended from a filling spout, and when the weight of the bag contents reaches a predetermined amount, the filling operation is automatically discontinued. It has been found that increased weighingaccuracy can be obtained if the machine is provided with a chamber which can'be closed and pressurized during the filling operation, the chamber having an inlet valve which can be opened between successive filling operations to receive a charge of the material being fed into the bag.

However, in certain types of inlet valves now used in bag filling machines, such as a butterfly-type valve, the material in the chamber tends to block the movement of the valve member into its closed position. This prevents the pressure build-up within the chamber.

The present invention provides a door-type inlet valve which maintains an effective seal in spite of the presence of the small particles which would ordinarily tend to prevent movement of the valve into its closed position.

According to my invention, the inlet valve comprises a doorplate hingedly mounted within a casing of generally rectangular cross-section, the side edges of the doorplate being provided with wiping bars whichresiliently bear against the side walls of the casing to wipe the same clean of the particulate material which fills the chamber so that a pressure resistant seal may be effected between the doorplate and the side walls of the casing.

A feature of my invention is the provision of a novel hinge construction for the door which embodies a similar wiping seal'for that edge of the door which is adjacent the hinge. The arrangement whereby wiping seals are provided for three of the four door edges permits me to provide an improved air sweep arrangement for cleaning the fourth edge of the door. The arrangement is such that the air stream will have sufficient velocity to impart a substantial kinetic energy to the particulate material so that-the contacting surfaces will be swept clean even though the particles have to be blown .into a mass of overlying material which in turn is displaced upwardly.

The air sweep arrangement for the fourth edge of the door includes a baffle or wall inside of the casing, the edge of which serves as a doorstop against which the side surface of the fourth edge of the door abuts. An air stream is provided which blows between the abutting surfaces just prior to the time that they move into engagement with each other. Thus, the abutting surfaces are swept clean of particulate material by theair stream so that the fourth edge seal will be pressure resistant.

A further feature of my invention is the provision, in the inlet valve structure, of a free space which serves as an expansion .chamber to accommodate the particulate material that is displaced by the doorplate as it moves into its closed position.

The use of my door-type inlet valve provides a comparatively large opening so that the chamber may be rapidly filled. When packing certain types of material, .it ispossible for an experienced operator to fill from six to eight (SO-pound) bags each minute. Each filling operation comprises a bag-filling stage, and achamberfilling stage. The operator removes the bag from the spout and places an empty bag on the spout during the chamber-filling stage. He is able, with practice, to accomplish the bag replacement in a matter of two or three seconds. Therefore, a rapid filling inlet valve construction will materially speed up the entire operation.

Other objects, features and advantages of my invention will become apparent as the description proceeds.

In the drawings: FIGQl is a side elevation ofa bag filling machine embodying my invention;

FIG. 2 is a rear elevation thereof;

FIG. 3 is a plan view, with the feed hopper removed;

FIG. 4-is an enlarged vertical section of the inlet valve structure taken along line 4-4 of FIG. 3;

FIG-5 is a vertical section taken along line 5--5 of FIG. 4;

FIG. 6 is a section taken along line 66 of FIG. 5 showing the side wiping seal;

FIG. 7 is an enlarged section showing the hinge wiping seal;

FIG. 8 is a view similar to FIG. 4 but showing the door in almost closed position;

FIG. 9 is an elevation of the door shaft, with the location of the doorplate shown in broken lines.

FIG. 10 is a circuit diagram illustrating the operation of my invention.

With reference now to FIG. 1, the bag filling machine comprises the machine framework 10 which supports a chamber 11 adapted to receive the powdered or granular material to be fed into the bags. A bag-supporting spout l2 communicates with the lower end of the chamber 11 and is mounted at the upper end of a spout-supporting frame 13. The spout-supporting frame may also serve as a support for other equipment .not shown, such as a bag clamp and a bag saddle.

The spout-supporting frame 13 is connected to suit able scale mechanism 14, such as that shown in my US. Pat. No. 3,540,539, granted November 17, 1970. Since the spout-supporting frame 13 has relative vertical movement with respect to the machine framework 10, a flexible connection is provided between the spout 12 and the chamber 11 in the form of a rubber tube 15.

A valve-type bag 16 is slipped over the spout 12 to receive material located in the chamber 11. A fluidizing pad .17 .is located in the lower end of the chamber 11 and is connected to an air supply pipe 18 through valve 18a. Fluidization of the material in the lowerpart of the chamber 11 will cause the material to flow horizontally through the tube 15 and spout 12 into the bag 16. Aspout valve in the form of an air-actuated pinch valve 19 engages the rubber tube 15 to cut off the flow of fluidized material through the spout when the contents of the bag reach a predetermined weight, such as 50 pounds.

Located above thechamber 11 and secured thereto is an inlet valve structure 20 comprising a casing 21 and a door-type valve 22. The top wall 23 of the casing 21 has an inlet opening 46 (FIG. 3) for communication with a supply hopper 47 located above it.

As shown in FIG. 4, the casing 21 also includes side walls 24, a forwardly and upwardly inclined upper front wall 25, a lower front wall 26, an upper rear wall 27 and a lower rear wall 28. A horizontal plate 29 connects rear wall parts 27 and 28.

Externally mounted on the side walls 24 are bearing blocks 30 which receive the end portions 31 of the door shaft 32. As shown in FIG. 9, the central portion of the door shaft 32 is slabbed as at 33. The bearing blocks 30 include bushings 30a and an O ringseal 301; (FIG.

The door valve 22 comprises the shaft 32 and a doorplate 34 which overlies and is secured to the slabbed central portion 33 by bolts 35 and clampsing caps 36.

The doorplate 34 is preferably a laminated structure comprising side sheets 37 and spacer plates 38, which are spaced inwardly from the two side edges of the door to provide a channel 39.

A wiping bar 40 fabricated from a wear-resistant sealing material, such as Teflon, (tetrafluoroethylene (TFE) fluorocarbon resins and fluorinated ethylenepropylene (FEP) resins) is located within thechannel 39, one at each side edge of the doorplate 34, as shown in FIG. 6. An expansion element 41 is located between the spacer strip 38 and the wiping bar 40. This may be any suitable spring element; I have found that a length of rubber tubing is satisfactory, such as inch tubing having a wall thickness of 3/32 inch, the diameter being slightly greater than the width of the channel 39 so that the tubing is stressed.

One end portion 31 of the door shaft 32 is extended through the bearing block 30 and keyed to a collar 42, shown in FIGS. 2 and 3, which carries an arm 43. The arm is connected by a piston rod 44 to a fluid cylinder 45. The cylinder is supported at its outer end from a suitable bracket 48, as shown in FIG. 3.

In operation, the fluid cylinder. which is shown as an air-actuated cylinder, causes movement of the door between the open position shown in FIG. 4 and a closed position shown in dotted lines in FIG. 8. Throughout the range of movement, the wiping bars 40 are urged against the inner surface of the side walls 24 and sweep it clear of material to provide the desired pressure resistant seal.

A block 50 extends across the interior of the casing 21 at a point just beneath the horizontal connecting plate 29. This block has formed therein a semicylindrical recess or groove 51 ofa diameter equal to the diameter of the door shaft 32. The edge of the doorplate 34 adjacent the recess 51 is provided with a channel similar to channel 39, a wiping bar 52, and an expansion element similar to the expansion element 41. Thus, the wiping bar 52 is urged against the surface of the semicylindrical groove 51 to maintain the parts free of particulate material thus providing a wiping seal which prevents the escape of air.

A second opening 55 is provided in the top wall 23, and a porous fabric 56 overlies the opening 55 and is held in place by a frame 57. The frame 57 is removably,

secured to the top plate 23 by bolts and wing nuts 58 so that the fabric 56 can be removed for clean-out puroses. p A removable baffle plate 59, secured to the side walls 24 by suitable bolts, is located within the casing 21 in such a position that it forms a downwardly and rearwardly inclined continuation of the upper front wall 25. The lower edge 60 is so located that it will be engaged by the side surface of the free end portion of the doorplate 34. The lower edge 60 of the baffle plate 59 is cut at an angle so that the contact between the parts will be essentially a line contact.

Depending from the top plate 23 at the forward edge of the inlet opening 46 is a vertical baffle 61. As the material from the supply hopper 47 drops downwardly into the chamber 11 and the casing 21, both the chamber 11 and the casing 21 will be filled, except for two spaces 65, 67 defined by the lower edges of the baffles 59 and 61. Here the level of the material is indicated by the dotted lines 62 and 63 respectively, the exact slope being determined by the angle of repose of the particular material involved.

In the lower front wall 26 an air inlet opening 64 is formed, opening into the space 65 above the material level 62. Due to the baffle 59, the air inlet is never blocked.

As the doorplate 34 moves from its fully opened position of FIG. 4 toward its closed position, there will be a narrow gap 66 between the doorplate 34 and the edge 60 when the parts are in the almost closed position shown in FIG. 8. Low pressure air supplied through opening 64 into the space 65, at a rate of 35 cu. ft. per minute, for example, will remove the small amount of material adjacent the lower edge 60 and pass upwardly through the narrow gap 66 and through the material lying above'the baffle 59 into the space 67. The air escapes from the space 67 through the porous fabric 56.

This movement of the air sweeps the surfaces bounding the gap 66 free of particulate material so that when the parts move into fully closed position, an effective pressure seal is made.

As the width of the gap 66 approaches zero, the velocity of the air stream increases markedly so that sufficient kinetic energy is imparted to the particles as to force them into the overlying material which is loose and boiling.

Movement of the door 22 into its closed position will cause the material above and in front of the door to be displaced upwardly into the expansion chamber provided by the space 67. Thus the door does not have to work against the weight of the entire column of material in the supply hopper 47.

The low pressure air supplied through opening 64 is known in the art as top air, that is, the air which is supplied to the top of the chamber 11 to pressurize it during the bag-filling stage of the cycle. The top air supply is controlled by a suitable valve 69 (FIG. 2), such as a double-acting air actuated pinch valve operating on the flexible top air supply conduit 68.

The air cylinder 45 has a flow control valve 70 (FIG. 1) interposed in the actuating air connection 71 which closes the door valve 22. This acts as a delay means to slowup the operation of the door valve in order to assure that the top air is being fed into the space 65 as the door valve 22 moves into its almost closed position.

The operation is best illustrated by the electric circuit diagram of FIG. 10, although it is understood that an equivalent pneumatic control circuit may be employed.

The circuit 75 includes a cycle-initiating relay 76 having a start button 77 and also includes a cycleterminating switch 78 which is actuated by the scale mechanism 14. When the contents of the bag reaches a predetermined weight, the scale mechanism trips, and opens the switch 78 to terminate the bag-filling operation. The circuit 75 also includes a normally closed solenoid valve 79 and a normally open solenoid valve80. The normally closed solenoid valve 79, when energized, supplies actuating air to the door valve cylinder 45 and to the actuating cylinders of the various valves indicated in F l6. to perform the functions indicated by the legends, and which are associated with the bagfilling operation. This operation is initiated by depressing the start button, and terminated by the tripping of the scale mechanism.

Then the normally open solenoid valve 80 opens and supplies actuating air to the elements to cause them to perform the reverse function, and the elements remain in this condition until the start button 77 is again depressed.

Although only a preferred embodiment of my invention has been shown and described herein, it will be understood that various modifications and changes can be made in the construction shown without departing from the spirit of my invention, as pointed out in the appended claims.

I claim:

1. A bag filling machine adapted for receiving material from a supply bin comprising a pressure chamber, a bag filling spout connected with the lower part of said chamber, means for causing material in the lower part of said chamber to flow horizontally through said spout and into a bag, spout valve means for controlling the flow of material through said spout, means for supplying chamber air under pressure to said chamber, and inlet valve means for admitting material to said pressure chamber comprising a casing at the upper end of said pressure chamber and having front, side and back and top walls, an inlet opening in the top wall thereof, and a doortype valve located within said casing, a baffle extending from said front wall and having its lower edge portion spaced rearwardly from the front wall of said casing, said door valve comprising a shaft and a doorplate secured thereto, said shaft being rotatably mounted at a point rearwardly of said baffle and at a point above the lower edge thereof, said shaft and doorplate being movable between a substantially vertical open position, and a closed position in which the side surface of the outer portion of said doorplate will abut said lower edge of said baffle, door valve operating means, cycle initiating means for opening said spout valve means and for actuating said door operating means to close said door valve, cycle terminating means, including bag weight responsive means, for closing said spout valve and for actuating said door operating means to open said door valve when the contents of the bag have reached a predetermined weight.

2. A bag filling machine as claimed in claim 1 in which said door operating means comprises a doubleacting air cylinder, actuating air supply means for each end of said cylinder, said cycle initiating means controlling the actuating air supply for actuating said cylinder into the valve closed position, said cycle terminating means controlling the actuating air supply for moving said cylinder into the valve open position, said chamber air supply means including an air actuated chamber air supply valve, said cycle initiating means also controlling the actuating air to said chamber air supply valve to open same. and delay means interposed between said cycle initiating means and said door valve operating means to delay the movement of said door valve into fully closed position until after said chamber air supply valve has been opened.

3. An inlet valve structure for the upper end of the pressure chamber of a bag filling machine comprising a casing having front, side and back and top walls, an inlet opening in the top wall thereof, and a door-type valve located within said casing to control passage of particulate material into said pressure chamber, a baffle extending from said front wall and having its lower edge portion spaced rearwardly from the front wall of said casing, said door valve comprising a shaft and a doorplate secured thereto, said shaft being rotatably mounted at a'point rearwardly of said baffle and at a point above the lower edge thereof, said shaft and doorplate being movable between a substantially vertical open position, and a closed position in which the side surface of the outer portion of said doorplate will abut said lower edge of said baffle, door valve operating means, said doorplate extending the full width of said casing and having along its side edges sealing means engaging said side walls and means sealing the upper edge of .said doorplate adjacent said shaft with respect to the rear wall of said casing, and means supplying air to the upper part of said pressure chamber to pressurize said chamber .when said door is in closed position.

4. An inlet valve structure as claimed in claim 3 including control means for causing operation of said air supply means as said door valve moves into its almost closed position so as to sweep the abutting portions of said baffle edge and said doorplate side surface clean of particulate material.

5. An inlet valve structure as claimed in claim 4 in which said air supply means includes an inlet located in said front wall beneath said baffle.

6. An inlet valve structure as claimed in claim 4 in which said lower baffle edge is cut at an angle to provide essentially a line contact between said baffle edge and said doorplate.

7. An inlet valve structure as claimed in claim 3 which includes common control means for actuating said door valve operating means into valve closed position and for actuating said air supply means, and delay means interposed between said control means and said door valve operating means to assure that air will be supplied to said pressure chamber as said door valve moves into its almost closed position.

8. An inlet valve structure as claimed in claim 3 in which the side edges of said doorplate are recessed to provide a channel, said sealing means comprising a wiping bar disposed in each channel, and resilient means interposed between said wiping bar and the bot tom of said channel to resiliently urge said wiping bar against said side walls to provide a wiping seal.

9. An inlet valve structure as claimed in claim 3 in which said shaft is slabbed, said doorplate being secured to said shaft at said slabbed portion, said casing including a block overlying said shaft and doorplate and having a semi-cylindrical groove receiving said slabbed shaft portion, the upper edge of said doorplate being recessed to provide a channel, a wiping bar disposed in said channel,'and resilient means located between said wiping bar and the bottom of said channel to urge said wiping bar against the surface of the semicylindrical groove of said block to provide a wiping seal between the upper end of said door valve and said block.

rial.

11. An inlet valve structure as claimed in claim 10 in which said air supply means is also operative as said door valve moves into its almost closed position, said top wall above said expansion chamber having a porous portion permitting escape of said air through said expansion chamber and into the atmosphere.

Claims (11)

1. A bag filling machine adapted for receiving material from a supply bin comprising a pressure chamber, a bag filling spout connected with the lower part of said chamber, means for causing material in the lower part of said chamber to flow horizontally through said spout and into a bag, spout valve means for controlling the flow of material through said spout, means for supplying chamber air under pressure to said chamber, and inlet valve means for admitting material to said pressure chamber comprIsing a casing at the upper end of said pressure chamber and having front, side and back and top walls, an inlet opening in the top wall thereof, and a door-type valve located within said casing, a baffle extending from said front wall and having its lower edge portion spaced rearwardly from the front wall of said casing, said door valve comprising a shaft and a doorplate secured thereto, said shaft being rotatably mounted at a point rearwardly of said baffle and at a point above the lower edge thereof, said shaft and doorplate being movable between a substantially vertical open position, and a closed position in which the side surface of the outer portion of said doorplate will abut said lower edge of said baffle, door valve operating means, cycle initiating means for opening said spout valve means and for actuating said door operating means to close said door valve, cycle terminating means, including bag weight responsive means, for closing said spout valve and for actuating said door operating means to open said door valve when the contents of the bag have reached a predetermined weight.

2. A bag filling machine as claimed in claim 1 in which said door operating means comprises a double-acting air cylinder, actuating air supply means for each end of said cylinder, said cycle initiating means controlling the actuating air supply for actuating said cylinder into the valve closed position, said cycle terminating means controlling the actuating air supply for moving said cylinder into the valve open position, said chamber air supply means including an air actuated chamber air supply valve, said cycle initiating means also controlling the actuating air to said chamber air supply valve to open same, and delay means interposed between said cycle initiating means and said door valve operating means to delay the movement of said door valve into fully closed position until after said chamber air supply valve has been opened.

3. An inlet valve structure for the upper end of the pressure chamber of a bag filling machine comprising a casing having front, side and back and top walls, an inlet opening in the top wall thereof, and a door-type valve located within said casing to control passage of particulate material into said pressure chamber, a baffle extending from said front wall and having its lower edge portion spaced rearwardly from the front wall of said casing, said door valve comprising a shaft and a doorplate secured thereto, said shaft being rotatably mounted at a point rearwardly of said baffle and at a point above the lower edge thereof, said shaft and doorplate being movable between a substantially vertical open position, and a closed position in which the side surface of the outer portion of said doorplate will abut said lower edge of said baffle, door valve operating means, said doorplate extending the full width of said casing and having along its side edges sealing means engaging said side walls and means sealing the upper edge of said doorplate adjacent said shaft with respect to the rear wall of said casing, and means supplying air to the upper part of said pressure chamber to pressurize said chamber when said door is in closed position.

4. An inlet valve structure as claimed in claim 3 including control means for causing operation of said air supply means as said door valve moves into its almost closed position so as to sweep the abutting portions of said baffle edge and said doorplate side surface clean of particulate material.

5. An inlet valve structure as claimed in claim 4 in which said air supply means includes an inlet located in said front wall beneath said baffle.

6. An inlet valve structure as claimed in claim 4 in which said lower baffle edge is cut at an angle to provide essentially a line contact between said baffle edge and said doorplate.

7. An inlet valve structure as claimed in claim 3 which includes common control means for actuating said door valve operating means into valve closed position and for actuating said air supply means, and delay means interposed between said control means and said door valve operating means to assure that air will be supplied to said pressure chamber as said door valve moves into its almost closed position.

8. An inlet valve structure as claimed in claim 3 in which the side edges of said doorplate are recessed to provide a channel, said sealing means comprising a wiping bar disposed in each channel, and resilient means interposed between said wiping bar and the bottom of said channel to resiliently urge said wiping bar against said side walls to provide a wiping seal.

9. An inlet valve structure as claimed in claim 3 in which said shaft is slabbed, said doorplate being secured to said shaft at said slabbed portion, said casing including a block overlying said shaft and doorplate and having a semi-cylindrical groove receiving said slabbed shaft portion, the upper edge of said doorplate being recessed to provide a channel, a wiping bar disposed in said channel, and resilient means located between said wiping bar and the bottom of said channel to urge said wiping bar against the surface of the semicylindrical groove of said block to provide a wiping seal between the upper end of said door valve and said block.

10. An inlet valve structure as claimed in claim 3 which includes a second baffle depending from the front edge of said inlet opening and having its lower edge spaced from said first baffle, said second baffle being spaced rearwardly from said front wall to provide an expansion space, the material displaced by movement of said door valve into said closed position moving upwardly along said first baffle, said expansion space accommodating the displacement of said material.

11. An inlet valve structure as claimed in claim 10 in which said air supply means is also operative as said door valve moves into its almost closed position, said top wall above said expansion chamber having a porous portion permitting escape of said air through said expansion chamber and into the atmosphere.

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