Pipe core clean out system

Information

  • Patent Grant
  • 6397923
  • Patent Number
    6,397,923
  • Date Filed
    Thursday, July 29, 1999
    25 years ago
  • Date Issued
    Tuesday, June 4, 2002
    22 years ago
Abstract
A system for removing waste material from the bell end of a cast iron pipe is disclosed. The system has both a cleaning assembly and an exhaust system. The cleaning assembly has a plurality of wire brushes mounted on a shaft. The shaft is mounted on a cart that also supports a movable part of the exhaust system. The cart moves the wire brushes and part of the movable part of the exhaust system into and out of the bell end of the pipe. A motor on the cart rotates the shaft and brushes, and a tilt mechanism tilts the brushes down to contact the pipe. The pipe is rotated about its central longitudinal axis as the brushes contact and clean the pipe. The rotating brushes clean the sand core from the end of the pipe, and the waste sand is drawn by the exhaust system to the bag house where it is filtered. The exhaust system also includes a stationary duct. The stationary duct has a door and a chute. Larger chunks of waste sand can be removed from the exhaust system through the door and chute.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to the production of metal pipe, and more particularly, to the production of cast ductile iron pipe with bell ends formed using sand cores, and to a system for removing the sand cores from the cast pipe before the pipe is heat treated.




2. Description of the Prior Art




In the production of objects such as elongate cast metal pipes, centrifugal casting has been commonly used. In such a casting operation, the pipe is cast in a cylindrical mold. Molten metal, such as iron, is fed into the mold through a trough. The trough has a spout at one end which is curved toward the sidewall of the mold. A sand core is inserted into the bell end of the mold to form the inside contour of the pipe bell. The bell end of the pipe's inside contour typically includes one or more annular grooves or depressions defining a gasket seat area to receive a gasket. The mold is rotated and once it is brought up to the appropriate speed, molten metal is poured into the trough. Once the bell end of the pipe has formed, the mold is moved horizontally while rotating. The stream of molten metal discharged from the spout flows tangentially onto the surface of the mold, where it is held in place by centrifugal force. The molten metal forms a homogeneous pipe with a cylindrical bore.




After the pipe has been completely cast, the mold is kept rotating until the pipe has cooled to a desired temperature. The pipe must then be taken from the casting machine and transferred to a heat treating furnace. In some instances, the sand cores are not removed from the cast pipe before annealing; instead, the sand core is allowed to disintegrate at the temperatures in the annealing oven. However, in other types of production, it is desirable to remove the sand core from the bell end of the pipe before the pipe enters the heat treating furnace. This removal of the sand core is particularly important in plants in which the pipe is set vertically and supported on its bell end in the heat treating furnace; remnant pieces of the sand core could cause the pipe to be off-balance in the furnace, and risks toppling of the pipe.




Traditionally, the sand cores have been manually removed. In the manual process, a worker hits the sand core with a hammer to break the core into smaller pieces, and then scrapes out the pieces of the core using a hoe-type of tool. However, this process has required the worker to be in close proximity to the hot pipe, and has been time consuming, adding to the expense of producing cast iron pipe.




SUMMARY OF THE INVENTION




The present invention addresses the problem of removing sand cores from the bell ends of cast metal pipes in an efficient manner.




In another aspect, the present invention provides a system for removing a sand core from a cast iron pipe in a plant for making ductile iron pipe. The ductile iron pipe has a bell end, a hollow interior and an interior surface. The plant has a casting station for casting the iron pipe with a sand core to define the shape of at least a part of the interior surface of the pipe at the bell end of the pipe. The plant also has a heat-treating station downstream from the casting station to heat treat the pipe. The system for removing the sand core is positioned so that the sand core is removed before the cast pipe reaches the heat-treating station. The sand core removal system includes a brush assembly and an exhaust system. The brush assembly includes a shaft with a central longitudinal axis and a brush mounted on the shaft. The brush assembly is rotatable about the central longitudinal axis of the shaft to clean core sand from the pipe. The exhaust system is positioned to draw core sand away from the pipe after the core sand has been cleaned from the pipe. The exhaust system includes a hood. At least part of the brush is positioned within the hood.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a top plan view of an example of a pipe manufacturing facility illustrating the pipe casting station, heat treating station, and location of the system for removing core sand of the present invention, with the parts simplified for clarity;





FIG. 2

is a side elevation of an embodiment of the system for removing waste core sand material of the present invention, shown with a brush assembly in a retracted and raised position with respect to the bell end of a cast metal pipe, shown in cross-section and with a sand core at the bell end of the pipe;





FIG. 3

is a side elevation of the system of

FIG. 2

, shown with the brush assembly in an extended and lowered position with respect to the bell end of a cast metal pipe, shown in cross-section and with the sand core removed;





FIG. 4

is an end view of the linearly-movable cart, tilting frame and drive mechanism for the cart with the exhaust system shown in section, taken along line


4





4


of

FIG. 3

, and showing the tilt frame in the position shown in

FIG. 2

to position the brush assembly in the raised position;





FIG. 5

is an end view of the linearly-movable cart, tilting frame and drive mechanism for the cart with the exhaust system shown in section, taken along line


5





5


of

FIG. 3

, and showing the tilt frame in the position shown in

FIG. 3

to position the brush assembly in the lowered position;





FIG. 6

is a top plan view of the linearly-movable cart, tilting frame and brush assembly of the waste core sand removal system of

FIGS. 2-3

, with parts of the exhaust system and parts of the support structure for the movable hood and duct removed for clarity;





FIG. 7

is an end view taken along line


7





7


of

FIG. 3

, with parts removed for clarity, showing the hood of the exhaust system and part of the brush assembly of the waste core sand removal system;





FIG. 8

is an enlarged quarter section view of the bell end of a cast metal pipe with the sand core in place on the pipe, with the brush assembly and hood of the waste core sand removal system in the interior of the pipe, and with the brush assembly in the raised position;





FIG. 9

is an enlarged quarter section view of the bell end of the cast metal pipe of

FIG. 8

, shown with the brush assembly in the lowered position and the sand core removed;





FIG. 10

is an enlarged quarter section view of the bell end of another size cast metal pipe, with the sand core in place on the pipe, with the brush assembly and hood of the waste core sand removal system in the interior of the pipe, and with the brush assembly in the raised position;





FIG. 11

is an enlarged quarter section view of the bell end of the cast metal pipe of

FIG. 10

, shown with the brush assembly in the lowered position and the sand core removed;





FIG. 12

is an enlarged quarter section view of the bell end of another size cast metal pipe, with the sand core in place on the pipe, with the brush assembly and hood of the waste core sand removal system in the interior of the pipe, and with the brush assembly in the raised position; and





FIG. 13

is an enlarged quarter section view of the bell end of the cast metal pipe of

FIG. 12

, shown with the brush assembly in the lowered position and the sand core removed.











DETAILED DESCRIPTION




An example of a manufacturing facility or plant


10


for manufacturing an elongate product such as cast ductile iron pipe is shown in FIG.


1


. The illustrated plant


10


includes a casting station


12


for casting iron pipe


14


. The casting station


12


may include any centrifugal casting machine


16


known in the art. The illustrated plant


10


also includes a annealing or heat-treating station


18


downstream from the casting station


12


, where the cast iron pipe is heated and cooled to produce the desired properties in the metal. In the illustrated embodiment, the heat-treating station


18


includes a carousel


20


with support stations


22


for supporting pipe and moving the pipe into, through and out of a heat-treating furnace. In the illustrated heat-treating furnace, the pipe


14


are vertical when passed through the furnace of the heat-treating station, supported on their bell ends


24


on the support stations


22


.




The pipe


14


at the casting station


12


that has exited the casting machine


16


is disposed with its central longitudinal axis


19


in a substantially horizontal position. To move the pipe from the casting station


12


to the heat treating station


18


, an overhead crane


26


is-provided. The overhead crane lifts the pipe from the casting station


12


and moves along a runway


28


to move the pipe


14


toward the next production station. Typically, the overhead crane transports the pipe in a substantially horizontal position, and includes bails with powered rollers for rotating the hot pipe during transport. Commercially available cranes may be used. A suitable crane is a P&H crane available from P&H/Morris Material Handling, Inc. of Milwaukee, Wis. Preferably, the crane bail rotates the pipe at a rate of about 3-6 rpm. It should be understood that this crane and rate of rotation are identified as examples only, and the invention is not limited to a particular crane or rate of rotation. The plant may include pipe moving apparatuses


30


,


32


as disclosed in U.S. patent application Ser. No. 09/203,902, filed on Dec. 12, 1998 and entitled “Pipe Moving Method, Apparatus and System” for up-ending and down-ending the pipes to place them on and remove them from the carousel supports


22


. A twit conveying system


34


may be adjacent to the pipe downender


32


for conveying the annealed pipe to another station in the plant.




As shown in

FIGS. 2-3

, the pipe


14


has a hollow interior


33


, and an interior surface


35


. The pipe


14


has an opening


37


at the bell end


24


. The interior surface


35


of the bell end


24


of the pipe


14


is defined at the casting station


12


by an annular sand core shown at


36


in

FIGS. 2

,


8


,


10


and


12


. After casting, the sand core is no longer needed and comprises waste material. In the illustrated type of plant, the sand core


36


is removed before the pipe reaches the heat-treating station


18


. Since in the heat-treating furnace the pipe is supported vertically, core sand at the bell end could cause the pipe to be askew on the supports


22


.




The present invention provides a system for removing the waste sand core material from the cast iron pipe. The waste sand core removal system is shown at


40


in

FIGS. 1-3

. The waste sand core removal system is connected to the plant bag house


42


in the illustrated embodiment, and the bag house is connected to an air-moving device


44


to draw air and sand through the sand core removal system to the bag house


42


. The air-moving device


44


may comprise any standard fan, and preferably is one that moves or draws at least about 12,000 cubic feet per minute of air through the sand core removal system


40


. The bag house is of standard design for filtering air in such manufacturing facilities. The sand core removal system


40


is positioned upstream of the heat-treating station


18


so that the sand core is removed from the pipe


14


before the pipe


14


reaches the heat-treating station


18


.




It should be understood that the core sand removal system of the present invention can be used in plant layouts other than that illustrated in

FIG. 1

, and that the invention is not limited to that plant layout. Moreover, the system of the present invention is not limited to plants having heat-treating furnaces with vertically-disposed pipes.




The illustrated system


40


for removing sand cores from metal pipes includes a cleaning assembly


46


and an exhaust system


48


. The cleaning assembly


46


serves to clean the core sand from the pipe. The cleaning assembly


46


is rotatable. As it rotates against the sand core, the cleaning assembly cleans waste core sand material from the pipe by rubbing, wiping, scouring, breaking off or otherwise loosening the sand off of the interior surface of the pipe. The exhaust system is positioned to move or draw the waste core sand material away from the pipe after the waste core sand material has been cleaned from the pipe.




In the illustrated embodiment, the cleaning assembly


46


comprises a brush assembly. The illustrated brush assembly includes a shaft


50


and a plurality of annular brushes


52


mounted concentrically on the shaft


50


. The shaft


50


and annular brushes


52


are rotatable about the central longitudinal axis


54


of the shaft


50


.




Although the brush assembly


46


could comprise a single brush on a shaft, use of a plurality of individual annular brushes


52


is advantageous. Brushes of various diameters may be selected and grouped so that the outer contour of the brush assembly corresponds generally to the contour of the interior surface


35


of the bell end


24


of the pipe


14


. Thus, as shown in

FIGS. 8-13

, larger diameter brushes may be provided to correspond with grooves, recesses or indentations


47


in the interior surface


35


of the bell end


24


of the pipe


14


. Smaller diameter brushes may be provided to correspond with raised areas


49


of the interior surface


35


of the bell end


24


of the pipe


14


and areas of decreased pipe inner diameter. In FIGS.


8


,


10


, and


12


, some of the larger diameter brushes are shown at


52




a


and some of the smaller diameter brushes are shown at


52




b


. As shown in

FIGS. 9

,


11


and


13


, use of the illustrated combinations of brushes allows for part of the brush assembly to reach into the grooves or indentations


47


when the brush assembly


46


is in the lowered position.




Various combinations of brushes are shown in

FIGS. 8-13

. In the embodiment of

FIGS. 8-9

, combinations of 6-inch diameter, 6-½-inch diameter, and 7-inch diameter brushes are used, totaling


15


individual brushes. Other combinations and numbers of brushes may be used, as shown in the embodiment of

FIGS. 10-11

and the embodiment of

FIGS. 12-13

. Other diameter brushes may also be used, such as 8-inch Manufacturing unit of Jason Incorporated of Cleveland, Ohio, as knot wire wheel brushes, using either stainless steel wire or steel wire for the brush element


51


mounted on annular arbors


53


. The arbors


53


are mounted concentric on the shaft


50


, and may be keyed to the shaft if desired. It should be understood that these brushes and brush diameters are provided by way of example only; other brushes may be used in other configurations, and it is expected that other materials may be used as well. It is expected that one of ordinary skill in the art would consult a brush supplier to obtain a suitable brush for the environment, and would select a material that will withstand the temperatures of the pipe at this stage of the manufacturing process, and select a material that will be economical while providing a satisfactory working life.




It should also be understood that devices other than brushes may be used in the cleaning assembly. For example, it may be desirable to use grinding wheels, or combinations of wheels and brushes for the cleaning assembly. Alternatively, a bladed object could be used to remove the core without contacting the iron pipe; a blade or knives could be used for scoring the core. Instead of a rotating cleaning assembly, a needle gun or chipping hammer could be used. The selected cleaning mechanism can be moved into and out of the interior of the pipe to clean the waste core material from the pipe.




The shaft


50


of the cleaning or brush assembly


46


may comprise a single piece or a multiple-piece element. For example, the shaft may include a mandrel at the end to which the brushes are mounted. The shaft


50


or mandrel may have a reduced diameter portion


56


adjoining an annular shoulder


59


at the juncture with the remainder of the larger diameter part of the shaft, as shown at


56


in

FIGS. 8-13

. A washer


58


may bear against the shoulder


59


, with the first brush


52


placed against the washer


58


. Another washer


60


may be placed against the last brush


52


, and then the entire group of brushes may be locked in place with a nut


62


threaded onto the free end


84


of the shaft


50


or mandrel. If production shifts to another type of pipe, the nut


62


can be removed so that the brushes


52


may be moved or replaced to change the contour of the brush assembly. Worn brushes can also be readily replaced in this manner. The nut


62


can then be replaced and tightened to lock the new group of brushes in place on the shaft or mandrel.




In the illustrated sand core removal system


40


, the cleaning or brush assembly


46


is moved in three ways: the cleaning or brush assembly


46


is moved linearly into and but of the hollow interior


33


of the pipe in a direction parallel to the central longitudinal axis


19


of the pipe


14


; the cleaning or brush assembly


46


is pivotable about a tilt axis


70


to move the assembly between the raised position shown in

FIG. 2

to the lowered position shown in

FIG. 3

; and the cleaning or brush assembly


46


is rotatable about the central longitudinal axis


54


of the shaft


50


.




To move the cleaning or brush assembly


46


linearly toward and away from the pipe


14


, the illustrated cleaning or brush assembly


46


is mounted on a linearly-movable cart


72


. In the illustrated embodiment, the linearly movable cart


72


includes a frame


74


mounted on two sets of wheels


76


and axles


78


. The frame


74


is mounted on the axles through pillow blocks


80


or other suitable bearings. The wheels


76


are set to roll along a set of parallel rails


82


. The rails


82


are supported on I-beams


84


. The I-beams


84


are supported on a support frame


86


that rests on the plant floor. The illustrated support frame


86


positions the cart


72


and brush assembly


46


above the plant floor, aligned generally with the level of pipes carried by the overhead crane


26


. To prevent the rolling cart


72


from tipping over, a pair of elongate rods


88


are provided, overlying and generally parallel to the rails


82


above the wheels


76


, serving to trap the wheels


76


between the rods


88


and the rails


82


. The ends of the rods


88


may be connected to suitable supports. An outer guard


90


may extend along the length of both of the rails


82


and rods


88


. For clarity of illustration, the guard


90


is not shown in FIG.


6


.




The illustrated embodiment of the sand core removal system includes a drive mechanism


92


. The drive mechanism


92


serves to move the linearly movable cart


72


, tilting frame


102


and cleaning or brush assembly


46


toward and away from the pipe


14


. The illustrated drive mechanism


92


moves the cart


72


along the rails


82


, and comprises a pneumatic drive, with a cylinder


94


and a piston


96


. The cylinder


94


is secured to the support frame through a cross-beam


98


. The piston


96


is secured to the frame


74


of the rolling cart


72


. A suitable drive mechanism


92


is a commercially available pneumatic cylinder from Parker Hannifin Corp. of Cleveland, Ohio, model 3.25 DB-2AU14A 16.000, having a stroke length of 16 inches, a cylinder diameter of 3.25 inches, and operating at a pressure of 100 psi. It should be understood that this drive mechanism is identified for purposes of illustration only, and that the present invention is not limited to this particular drive and is not limited to hydraulic drives. Other types of drives may be used such as hydraulic cylinders, chain and sprocket, rack and pinion, and standard linear drive mechanisms, for example. However, a pneumatic drive is preferred; since the cart is moved up to where an element carried by the cart contacts the pipe, the give provided by a pneumatic drive is advantageous.




The frame


74


of the rolling cart


72


has a pair of spaced upright channels


100


that carry and support a tiltable frame


102


. The tiltable frame


102


has a pair of spaced upright bars


104


carrying pins


106


that are received in bearings


108


supported on the upright channels


100


. The pins


106


have co-linear central longitudinal axes along the tilt axis


70


of the tiltable frame


102


. Thus, the tiltable frame


102


is suspended on the upright channels


100


of the rolling cart


72


, and may pivot or tilt about the tilt axis


70


defined by the central longitudinal axes of the pins


106


. As shown in

FIG. 6

, the tilt axis


70


is spaced from and parallel to the central longitudinal axis


54


of the shaft


50


of the brush assembly


46


.




The tiltable frame


102


also includes a base plate


110


connected to the two upright bars


104


through welding or other suitable connection means. An electric motor


112


is mounted off-center on the base plate


110


, along with two off-center support plates


114


. The off-center support plates


114


may be connected to the base plate through welding, for example, or other suitable connection means. The off-center support plates


114


are spaced and include aligned apertures. A spacer tube


116


extends between and is connected to the off-center support plates


114


. The shaft


50


of the brush assembly


46


extends through the aligned apertures of the off-center support plates


114


, through the spacer tube


116


and through suitable bearings


118


at each off-center support plate


114


. Thus, the cleaning or brush assembly


46


is supported on the tiltable frame


102


with the shaft central longitudinal axis


54


parallel to the tilt axis


70


of the tiltable frame


102


. As shown in

FIG. 6

, the annular brushes


52


and shaft


50


extend out beyond the tiltable frame


102


and linearly-movable cart


72


.




One end of the shaft


50


is connected to a mechanism such as a drive wheel that is connected through a drive belt or chain


120


to be driven by the motor


112


. Preferably, the motor


112


selectively rotates the shaft


50


, and rotation of the shaft


50


and the entire brush assembly


46


is preferably at a rate of about 1700-1800 rpm. The drive belt or chain


120


may be covered by a guard


122


. A standard squirrel cage 3-phase motor may be used.




In the illustrated embodiment, a powered tilting device


124


is connected to the linearly movable cart


72


and to the base plate


110


of the tiltable frame


102


to tilt the tiltable frame


102


about its tilt axis


70


to thereby move the cleaning or brush assembly


46


toward and away from the interior surface


35


of the pipe


14


at the bell end


24


. The powered tilting device


124


may comprise a pneumatic drive, with a cylinder pivotally connected to the frame


74


and the piston pivotally connected to the other frame


102


. A suitable powered tilting device is a commercially available pneumatic cylinder from Parker Hannifin Corp. of Cleveland, Ohio, model 3.25DB-2AU14A 6.000, having a stroke length of 6 inches, a cylinder diameter of 3.25 inches, and operating at a pressure of 100 psi. It should be understood that this powered tilting device is identified by way of example only, and that the present invention is not limited to this particular tilting device or to pneumatic devices. Other commercially available mechanisms may be used, such as hydraulic cylinders, for example. However, a pneumatic device is preferred to bounce the brushes up and down on the core, and to yield or give under excessive pressure.




As shown in

FIGS. 2-3

, in the illustrated embodiment, the tilt axis


70


is generally parallel to the central longitudinal axis


19


of the pipe; pivoting the cleaning or brush assembly about the tilt axis


70


moves the axis of rotation


54


toward and away from the interior surface


35


of the pipe. In the illustrated embodiment, the axis of rotation


54


of the cleaning or brush assembly


46


is parallel to the central longitudinal axis


19


of the pipe


14


, although it should be understood that this alignment is not necessary.




As shown in

FIGS. 2-3

, the linearly-movable cart


72


also supports part of the exhaust system


48


of the sand core removal system


40


. The exhaust system


48


in the illustrated embodiment includes a hood


130


and a movable duct


132


supported to move with the cart


72


and cleaning or brush assembly


46


. The hood


130


overlies at least part of the cleaning or brush assembly


46


; in the illustrated embodiment, the hood


130


overlies the annular brushes


52


of the brush assembly


46


and is movable into and out of the hollow interior


33


of the pipe


14


through the opening


37


at the bell end


24


of the pipe


14


. The hood


130


is connected to the movable duct


132


so that the movable duct may receive exhaust from the hood.




As shown in

FIGS. 2-5

, the linearly-movable cart


72


in the illustrated embodiment has a pair of upright metal angles


131


attached to each upright channel


100


. Each pair of upright metal angles


131


is connected to a horizontal angle


133


that is connected to two horizontal angles


135


that support the movable exhaust duct


132


. These connections can be through welding, nuts and bolts, screws, or other standard connections. The hood


130


is connected to and supported by the movable duct


132


.




As shown in

FIGS. 2-3

, the exhaust system


48


also includes a stationary duct


140


connected to receive exhaust from the movable duct


132


when the hood


130


is within the interior


33


of the pipe


14


. The stationary duct


140


remains stationary as the linearly movable cart


72


, movable duct


132


and hood


130


move toward and away from the pipe


14


. In the illustrated embodiment, the stationary duct


140


is telescopically received in the movable duct


132


as the rolling cart


72


, movable duct


132


and hood


130


are moved by the pneumatic cylinder


94


. In the illustrated embodiment, the stationary duct


140


leads into the bag house


42


. The bag-house fan


44


serves as an air-moving device for moving air and waste material or sand from the core


36


into the hood


130


and through the movable duct


132


to the stationary duct


140


, and from the stationary duct to the bag house


42


.




As shown in

FIGS. 2-3

, the bottom of the hood


130


is spaced slightly above the interior surface


35


of the pipe


14


, leaving a small gap


142


. The gap


142


allows for air to enter the hood


130


, pulling loose sand from the core


36


with it, as indicated by the arrows labeled


143


in FIG.


3


.




As shown in

FIGS. 2-3

. the stationary duct


140


of the illustrated embodiment also includes a door


150


and a chute


152


for waste material. The chute


152


and door


150


are positioned at the location where the stationary duct


140


extends upward at a steep angle. Any large chunks of sand from the core that are too heavy for the fan


44


to pull up this steep incline into the bag house may accumulate at the chute


152


upstream of the door


150


in the area shown at


153


. The pressure drop in the stationary duct


140


due to operation of the fan


44


will generally keep the door


150


closed. However, when the pressure in the stationary duct


132


is beyond a set level, the door


150


may open a passage to the chute


152


for the waste material or debris. The chunks of waste material or debris will then travel down the chute


152


for collection and disposal. The level of pressure in the stationary duct may be varied by slowing or stopping the fan


44


so that the door


150


may be opened.




The system for removing sand cores of the present invention may be computer controlled. As illustrated schematically in

FIG. 1

, a computer or programmable logic component


200


may be connected to receive input, shown at


202


in

FIG. 1

, such as an electrical signal from the crane or from a sensor such as a limit switch to sense when the crane has been aligned with the brush assembly and its linear travel stopped. The programmable logic component


200


can be connected through outputs shown at


204


to control operation of the drive mechanism


92


to move the cart


72


along the rails


82


, to start the motor


112


to begin rotating the brush assembly


46


, and after the brushes


52


and hood


130


have moved into the interior


33


of the pipe


14


, to actuate the powered tilting device


124


to tilt the frame


102


to lower the rotating brushes. The programmable logic component


200


could also be connected to control operation of the powered rollers on the crane


26


so that the direction of rotation of the pipe can be changed during the waste removal process. Alternatively, a separate programmable logic component could control the crane. The programmable logic element


200


could also be connected to control operation of the fan


44


so that the speed of rotation can vary depending upon use.




In the illustrated embodiment, a vertical plate


145


is attached to the exhaust system


48


near the brushes


52


. As shown in

FIG. 3

, the cart


72


is pushed toward the pipe until the plate


145


contacts the bell end of the pipe, or until the plate contacts the outer pancake portion


210


of the core


36


. The plate


145


has apertures through which the shaft


50


extends, and provides an opening through which air and waste may travel to enter the exhaust system. Since the distance between the plate


145


and the brushes is fixed, moving the cart


72


until the plate


145


contacts the pipe or core ensures that the brushes


52


are properly positioned within the pipe. The distance between the plate


145


and the brushes


52


can be preset and would depending on whether the pipe or the core is contacted by the plate


145


.




A commercially-available programmable logic component may be used. A suitable programmable logic and motion control system is available from Allen-Bradley Co./Rockwell Automation, of Milwaukee, Wis. and other locations, with standard ladder logic suitably programmed, as will be understood by those skilled in the art. It is expected that the supplier would be consulted for selection of an appropriate model of component. A standard PLC with standard logic may be programmed by one skilled in the programming art, such as an electrical engineer, or more sophisticated programming could be developed if desired. It should be understood that this computer control is identified for purposes of illustration only, and that the invention is not limited to use of programmable logic components, to components from this supplier, or to any particular program, computer or PLC.




The present invention also defines a method of removing core sand from the bell end of a cast metal pipe using the system as described above. Preferably, the step of removing the core sand from the cast metal pipe occurs before the pipe is heat-treated at the heat-treating station


18


.




In operation, after a pipe


14


has been cast at the casting station


12


, the pipe is substantially horizontal. The crane


26


is moved along the runway


28


to a position overlying the pipe


14


, and the horizontal pipe is lifted by the crane. Powered rollers on the crane bails rotate the pipe


14


about its horizontal central longitudinal axis


19


. The crane


26


moves along a path defined by the runway


28


until the pipe is aligned with the brush assembly


46


of the sand core removal system


40


. The crane stops its linear movement at the sand core removal system


40


, but the powered rollers preferably continue to rotate the pipe


14


about its central longitudinal axis


19


. At this time, the linearly-movable cart


72


is in the retracted position shown in FIG.


2


. Preferably, the support frame


86


for the sand core removal system


40


positions the removal system above the plant floor, with the axis


54


of the shaft


50


positioned between the level of the pipe central axis


19


and the level of interior surface


35


of the bottom of the pipe


14


.




The linear drive mechanism


92


is actuated to push the linearly-movable cart


72


along the rails


82


toward the pipe, and the brushes


52


and hood


130


enter the opening


37


at the bell end


24


of the pipe, and move into the interior


33


of the pipe. At this time, the brushes


52


are spaced above the sand core


36


in the pipe. The air-moving device


44


is already operating so that air is moved or drawn into the hood


130


through the gap


142


, and into the movable duct


132


and stationary duct


140


. From the stationary duct


140


, the air is moved or drawn into the bag house


42


where it is filtered. The cart


72


fit stops forward motion when the plate


145


contacts the exterior of the bell end of the


65


pipe. With the cart so positioned, the brushes of the cleaning assembly should be properly aligned with the corresponding shape of the pipe interior, as shown in

FIGS. 8

,


10


and


12


.




The motor


112


is actuated to commence rotating the brush assembly


46


. After the brushes have commenced rotating, the tilting device


124


is actuated. The tilting device pushes upward on one side of the base plate


110


of the tiltable frame


102


, on the side supporting the motor


112


in the illustrated embodiment. The tiltable frame


102


tilts about is tilt axis


70


, lowering the brushes to the lowered position as shown in FIG.


3


. The brushes


52


, rotating at speeds of 1700-1800 revolutions per minute, contact the rotating sand core


36


, breaking the sand core into smaller pieces to clean the sand from the interior surface


35


of the bell end


24


of the pipe


14


. The draft from the air-moving device


44


pulls the waste sand into the hood


130


of the exhaust system


48


. Smaller chunks and particles of sand are drawn into the bag house


42


, where they are filtered from the air and collected. Larger chunks of waste sand that do not travel up the steeply inclined part of the stationary duct


140


are collected adjacent the door


150


to the chute


152


at collection location


153


. The door


150


is closed at this time due to the pressure differential. The pipe continues to rotate throughout the time the brushes are cleaning the sand from the pipe.




After a predetermined time, the direction of rotation of the pipe


14


on the crane rollers may be reversed to improve cleaning of the pipe. Alternatively or in addition, the direction of rotation of the brush assembly


46


could be reversed. In addition, instead of keeping the brushes


52


in the lowered position throughout the cleaning cycle, it may be desirable to bounce the brushes up and down against the surface of the sand core.




As shown in

FIGS. 8-13

, the overall contour of the cleaning or brush assembly


46


allows the longer bristles of some of the brushes to reach into the grooves or indentations


47


of the interior surface


35


of the pipe to insure that the interior surface


35


is thoroughly cleaned of sand.




The pancake portion of the sand core


36


, on the outside of the pipe


14


and shown at


210


in

FIGS. 2

,


8


,


10


and


12


may be removed manually with a hammer or the like before or after the pipe reaches the sand core removal system


40


. Alternatively, the cleaning or brush assembly


46


could include brushes or other devices that would also clean the pancake off of the pipe.




After the sand core has been cleaned from the interior surface


35


of the pipe


14


, the brush assembly


46


may be raised away from the surface


35


back to the position shown in

FIG. 1

by retracting the piston of the tilting device


124


, thereby pulling downward on the motor side of the base plate


110


. As the motor side of the base plate


110


is pulled down, the tiltable frame


102


tilts about its tilt axis


70


to raise the brush assembly


46


. The motor


112


may be stopped and then the piston


96


of the linear drive


92


may be retracted into the cylinder


94


, thereby pulling the rolling cart


72


, the brush assembly


46


, hood


130


and movable duct


132


away from the pipe. As the movable assembly is pulled back, part of the stationary duct


140


telescopes into part of the movable duct


132


. The movable assembly is pulled back until the hood


130


clears the end of the pipe. The crane


26


is then actuated to begin moving linearly along the runway


28


to move the pipe downstream to the upender


30


. The pipe is then placed upright with its bell end


24


on one support station


22


of the carousel


20


. The carousel


20


is rotated to move the pipe through the heat-treating furnace


18


. The heat-treated pipe is removed from the support station


22


by the downender


32


and the pipe then moved to the conveying system


34


for finishing.




Preferably, air continues to move or be drawn through the exhaust system


48


even when the sand core removal system is in the position shown in FIG.


2


. The continuous flow of air should adequately cool the ducts between pipe cleanings. The air-moving device


44


may be slowed or stopped periodically so that the pressure in the stationary duct is beyond a set level, allowing the door


150


to be opened. When the door


150


is opened, larger chunks of waste sand that have collected at location


153


can then be removed through the chute


152


.




For removing sand cores from cast pipe, the materials used for the parts should be suitable for the anticipated temperatures in the area of the pipe. Generally, most of the parts of the brush assembly, exhaust system, linearly-movable cart and tilting frame are made of steel. Stainless steel may be used, although less expensive forms are desirable provided they provide a suitable working life.




Although the invention has been described in terms of removing a sand core from a cast metal pipe, it should be understood that the invention may be used to remove other waste materials from a casting. For example, the invention may be used in cleaning a pipe end by grinding the pipe after the sand core has been removed and after the pipe has been heat treated and cooled. Use of the exhaust system of the present invention in combination with the cleaning assembly in such a finishing operation can limit the amount of fine metal particles released to the plant environment. The expression “waste materials” should thus be understood to include the sand core in the pipe after casting as well as metal material to be removed in a finishing operation.




And although the present invention is shown with its exhaust system connected to the bag house for the plant, it should be understood that the exhaust system could be connected to a special collector. For example, it may be desirable to collect the sand from the sand core alone for recycling or for separate disposal. If the invention is used to collect metal particles, it may be desirable to collect these particles separate from other waste in the plant for recycling. Thus, the exhaust system could be connected to a separate collector or filter and air-moving device.




It should also be understood that although the illustrated embodiment uses power devices such as the pneumatic drives


92


and


124


to move the cart


72


and to tilt the frame


102


, these movements could be accomplished manually as well. Moreover, as discussed above, other types of drives may be used, such as hydraulic cylinders, chain and sprocket, rack and pinion and commercially available linear drives, although drives that yield and that allow the cleaning assembly to be bounced up and down are preferred.




Although the illustrated embodiment shows structures that allow for movement of the cleaning and exhaust assemblies into the pipe, relative movement could alternatively be accomplished by providing structures that move the pipe. For example, the exhaust system and cleaning assembly could be kept linearly stationary, and the pipe could be moved linearly toward and away from the cleaning assembly and hood. Instead of pivoting the cleaning assembly to raise and lower it, the pipe could be moved to contact the cleaning assembly.




It should also be understood that the cleaning or brush assembly


46


could be raised and lowered through means other than tilting, such as through a vertical lift mechanism. Alternatively, the shaft


50


of the cleaning or brush assembly could be made to pivot up and down about a horizontal axis perpendicular to the pipe central longitudinal axis


19


, to thereby move the cleaning assembly against and away from the interior surface of the pipe. In such cases, the system need not have a tilting frame as illustrated.




While only a specific embodiment of the invention has been described and shown, it is apparent that various alterations and modifications can be made therein. It is, therefore, the intention in the appended claims to cover all such modifications and alterations as may fall within the scope and spirit of the invention. Moreover, the invention is intended to include equivalent structures and structural equivalents to those described herein.



Claims
  • 1. A system for removing waste material from the bell ends of cast metal pipe, the pipe having a central longitudinal axis, a hollow interior and an interior surface, the system comprising:a casting station for casting a cast metal pipe having a bell end; waste material at the bell end of the cast metal pipe; a cleaning assembly to clean the waste material from the pipe, at least one of at least part of the cleaning assembly and the pipe being movable so that at least part of the cleaning assembly is inside the pipe and outside of the pipe at different times; and an exhaust system positioned to move waste material away from the pipe after the waste material has been cleaned from the pipe; wherein the exhaust system includes an intake, a first waste outlet and a waste flow path, the waste flow path extending to a position downstream from the first waste outlet, and wherein the first waste outlet and the waste flow path are positioned so that waste material of a relatively heavier weight exits the exhaust system through the first waste outlet and so that waste material of a relatively lighter weight travels through the waste flow path to a position downstream of the first waste outlet.
  • 2. The system of claim 1 wherein the cleaning assembly is pivotable about a tilt axis parallel to the central longitudinal axis of the pipe to move the axis of rotation toward and away from the interior surface of the pipe.
  • 3. The system of claim 1 wherein the cleaning assembly is rotatable about an axis of rotation and movable in and out of the pipe in a direction parallel to the central longitudinal axis of the pipe.
  • 4. The system of claim 3 wherein the axis of rotation of the cleaning assembly is parallel to the central longitudinal axis of the pipe.
  • 5. The system of claim 1 wherein the exhaust system includes a movable duct movable toward and away from the hollow interior of the pipe, a stationary duct connected to receive exhaust from the movable duct, and an air-moving device for drawing air and waste material into the movable duct and from the movable duct into the stationary duct.
  • 6. The system of claim 5 wherein the stationary duct includes a chute for waste material and a door to open a passage to the chute when pressure in the stationary duct is beyond a set level, said door defining said first waste outlet.
  • 7. The system of claim 5 wherein the exhaust system includes a hood supported to move with the cleaning assembly, the hood being connected to the movable duct.
  • 8. The system of claim 3 wherein the cleaning assembly includes a shaft having a central longitudinal axis and a brush mounted on the shaft, the central longitudinal axis of the shaft defining the axis of rotation for the cleaning assembly.
  • 9. The system of claim 8 further comprising:a linearly-movable cart; a tiltable frame supported on the cart, the tiltable frame being tiltable about a tilt axis, the cleaning assembly being supported on the tiltable frame with the shaft central longitudinal axis parallel to the tilt axis of the tiltable frame and with the shaft and brush extending out beyond the tiltable frame and the cart; a motor mounted on the tiltable frame for rotating the shaft; a powered tilting device connected to the cart and the tiltable frame to tilt the tiltable frame about its tilt axis to thereby move the brush of the cleaning assembly toward and away from the interior surface of the pipe; a drive mechanism for moving the cart, tilting frame and brush assembly toward and away from the pipe.
  • 10. The system of claim 9 wherein the exhaust system includes:a hood and a movable duct supported to move with the cart, the hood overlying at least a part of the cleaning assembly and being movable into and out of the hollow interior of the pipe, at least part of said hood defining the intake into the exhaust system; a stationary duct connected to receive exhaust from the movable duct when the hood is within the interior of the pipe, the stationary duct being stationary as the cart and movable duct and hood move toward and away from the pipe; and an air-moving device for drawing air and waste material into the hood and through the movable duct to the stationary duct.
  • 11. The system of claim 10 wherein the stationary duct includes a chute for waste material and a door to open a passage to the chute for the waste material when pressure in the stationary duct is beyond a set level, and wherein said door defines said first waste outlet.
  • 12. The system of claim 10 wherein the cleaning assembly has a plurality of brushes mounted concentrically on the shaft, said brushes having varying diameters to define an outer contour corresponding generally to the contour of the interior surface of the bell end of the pipe.
  • 13. The method of removing core sand from the bell end of a cast metal pipe using the system of claim 1, the method including rotating the pipe about its central longitudinal axis while the cleaning assembly is within the interior of the pipe.
  • 14. The system of claim 1 wherein at least one of at least part of the exhaust system and pipe is movable so that at least part of the exhaust system is inside the pipe and outside the pipe at different times.
  • 15. In a plant for making ductile iron pipe with a bell end, a hollow interior and an interior surface, the plant having a casting station for casting the iron pipe with a sand core to define the shape of at least a part of the interior surface of the pipe at the bell end of the pipe, the plant also having a heat-treating station downstream from the casting station to heat treat the pipe, a system for removing the sand core from the cast iron pipe before the cast pipe reaches the heat-treating station comprising:a brush assembly including a shaft having a central longitudinal axis and a brush mounted on the shaft, the brush assembly being rotatable about the central longitudinal axis of the shaft to clean core sand from the pipe; and an exhaust system positioned to move core sand away from the pipe after the core sand has been cleaned from the pipe, tie exhaust system including a hood; wherein at least part of said brush is positioned within said hood.
  • 16. The method of removing core sand from the bell end of a cast iron pipe before the pipe is heat-treated using the system of claim 15.
  • 17. The system of claim 15 further comprising:a linearly-movable cart; a tiltable frame supported on the cart, the tiltable frame being tiltable about a tilt axis, the brush assembly being supported on the tiltable frame with the shaft central longitudinal axis parallel to the axis of the tiltable frame and with the shaft and brush extending out beyond the tiltable frame and the cart; a motor mounted on the tiltable frame for rotating the shaft; a powered tilting device connected to the cart and the tiltable frame to tilt the tiltable frame about its tilt axis to thereby move the brush assembly toward and away from the interior surface of the pipe; a drive mechanism for moving the cart, tilting frame and brush assembly toward and away from the pipe.
  • 18. The system of claim 17 wherein the exhaust system includes:a stationary duct connected to receive exhaust from the movable duct when the hood is within the interior of the pipe, the stationary duct being stationary as the cart and movable duct and hood move toward and away from the pipe; and an air-moving device for drawing air and sand from the core into the hood and through the movable duct to the stationary duct; and wherein the hood is movable into and out of the hollow interior of the pipe.
  • 19. The system of claim 18 wherein the stationary duct includes a chute for sand and a door to open a passage to the chute for the sand when pressure in the stationary duct is beyond a set level.
  • 20. The system of claim 15 wherein the brush assembly has a plurality of brushes mounted concentrically on the shaft, said brushes having varying diameters to define an outer contour corresponding generally to the contour of the interior surface of the bell end of the pipe.
  • 21. The system of claim 15 wherein the plant includes a crane for moving a pipe from the casting station to the heat treating station, the crane including rollers for rotating the pipe about its central longitudinal axis, the crane being movable through a path to align the pipe with the brush assembly.
  • 22. In a plant for making ductile iron pipe with a bell end, a hollow interior and an interior surface, the plant having a casting station for casting the iron pipe with a sand core to define the shape of at least a part of the interior surface of the pipe at the bell end of the pipe, the plant also having a heat-treating station downstream from the casting station to heat treat the pipe and a crane for moving a pipe from the casting station to the heat- treating station while rotating the pipe about its central longitudinal axis, a system for removing the sand core from the cast iron pipe before the cast pipe reaches the heat-treating station comprising:a brush assembly including a shaft and a plurality of annular brushes mounted concentrically on the shaft, the shaft having a central longitudinal axis and the shaft and annular brushes being rotatable about the central longitudinal axis of the shaft; a linearly-movable cart; a tiltable frame supported on the cart, the tiltable frame being tiltable about a tilt axis, the brush assembly being supported on the tiltable frame with the shaft central longitudinal axis spaced from and parallel to the tilt axis of the tiltable frame, the shaft and annular brushes extending out beyond the tiltable frame and cart; a motor on the tiltable frame for rotating the shaft; a drive mechanism for moving the cart, tilting frame and brush assembly toward and away from the pipe, the annular brushes being movable into the interior of the pipe; a powered tilting device connected to the cart and the tiltable frame to tilt the tiltable frame about its tilt axis to thereby move the brush assembly toward and away from the interior surface of the pipe; an exhaust system positioned to move core sand away from the pipe after the core sand has been cleaned from the pipe, the exhaust system including: a hood and a movable duct supported to move with the cart, the hood overlying the annular brushes of the brush assembly and moving into and out of the interior of the pipe; a stationary duct connected to receive exhaust from the movable duct when the hood is within the interior of the pipe, the stationary duct being stationary as the cart, movable duct and hood move; and an air-moving device for moving air and sand from the sand core into the hood and through the movable duct to the stationary duct; wherein at least one of the stationary duct and movable duct is received inside the other of said stationary duct and movable duct in a telescoping manner.
  • 23. The system of claim 22 wherein the interior surface of the bell end of the pipe has a contour and Wherein the annular brushes have diameters to define an outer contour corresponding generally to the contour of the interior surface of the bell end of the pipe.
  • 24. The system of claim 22 wherein the stationary duct includes a chute for sand and a door to open a passage to the chute when pressure in the stationary duct is beyond a set level.
  • 25. The method of removing core sand from a cast iron pipe using the system of claim 22.
  • 26. The method of claim 25 wherein the pipe is rotated about its central longitudinal axis as the brushes are rotated against the sand core.
  • 27. The method of claim 26 wherein the pipe is rotated in two different directions as the brushes are rotated against the sand core.
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Entry
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