Pressurized delivery system for abrasive particulate material

Information

  • Patent Grant
  • 6425804
  • Patent Number
    6,425,804
  • Date Filed
    Tuesday, March 21, 2000
    24 years ago
  • Date Issued
    Tuesday, July 30, 2002
    21 years ago
Abstract
A pressurized delivery system for abrasive particulate material includes a storage container adapted to contain the abrasive particulate material therein, an input pressure line adapted to communicate with a pressurized source, and a fluidizing pressure line communicating with the input pressure line and an inlet opening in the storage container. A back-pressure pressure line communicates with an unoccupied portion of the storage container and an output pressure line. The output pressure line, into which the abrasive particulate material is fed from the storage container, communicates with the input pressure line, the back-pressure pressure line, and an outlet opening of storage container. During operation, pressurized gas is released through the inlet opening and into the storage container such that the abrasive particulate material adjacent the outlet opening is fluidized and maintained flowable so as to achieve consistent flow of the abrasive particulate material through the outlet opening.
Description




THE FIELD OF THE INVENTION




The present invention relates generally to a system for delivering abrasive particulate material under pressure, and more particularly to a system which utilizes a pressurized source to fluidize and deliver abrasive particulate material for abrading a surface of another material, such as for abrading a portion of a silicon substrate of an ink-jet printhead to thereby form an ink fill slot in the silicon substrate.




BACKGROUND OF THE INVENTION




A conventional process, commonly referred to as sandblasting, combines abrasive particulate material, such as sand, with a pressurized source of gas, for example, air, to form an abrasive mixture under pressure and directs the abrasive mixture under pressure at a surface. Such a conventional sandblasting process is typically used for cleaning, polishing, or abrading the surface at which the abrasive mixture is directed. Existing sandblasting systems typically include a storage container adapted to contain the abrasive particulate material therein, and a pressure line through which the pressurized source of gas is directed and into which the abrasive particulate material is fed by gravity flow from the storage container.




More particularly, sandblasting has been employed to form an ink fill slot in a silicon substrate of an ink-jet printhead. Existing sandblasting systems employed for forming the ink fill slot typically rely on gravity flow, vibration of the storage container, and/or modulation of the pressure line to ensure discharge of the abrasive particulate material from the storage container, through a metering orifice, and into the pressure line. The vibration and/or modulation in these existing sandblasting systems, however, results in chaotic behavior, or inconsistent flow, of the abrasive particulate material through the metering orifice. This chaotic behavior resulting when the ink fill slot is formed with existing sandblasting systems is identified by random size and shape variations of the ink fill slot. Since the ink fill slot provides a supply of ink to a printing element of the ink-jet printhead during a printing process, a distance from the ink fill slot to the printing element effects the supply of ink to the printing element. Size and shape variations in the ink fill slot, therefore, can degrade printing performance.




Accordingly, a need exists for a system for delivering abrasive particulate material under pressure which provides consistent flow of the abrasive particulate material from a storage container, through a metering orifice, and into an output pressure line. In particular, there is a need for a method for more uniformly forming an ink fill slot in a silicon substrate of an ink-jet printhead.




SUMMARY OF THE INVENTION




One aspect of the present invention provides a pressurized delivery system for abrasive particulate material. The pressurized delivery system includes a storage container adapted to contain the abrasive particulate material therein, an inlet valve communicating with an inlet opening of the storage container, and a first flow path communicating with the inlet valve. A second flow path, adapted to communicate with a pressurized source of gas, communicates with the first flow path, and a third flow path communicates with the second flow path in parallel flow with the first flow path. A fourth flow path communicates with an unoccupied portion of an interior space of the storage container, and a fifth flow path communicates with the third flow path, an outlet opening of the storage container, and the fourth flow path. As such, a pressurized supply of the abrasive particulate material may be formed and delivered through the fifth flow path.




In one embodiment, the third flow path is in parallel flow with the first flow path from the second flow path.




In one embodiment, the abrasive particulate material includes sand, aluminum oxide, silicon carbide, quartz, or diamond dust. In one embodiment, the gas is air and in another embodiment, the gas is an inert gas for use, for example, when a material to be processed with the pressurized delivery system is sensitive to air and oxidation of the material is a concern.




In one embodiment, the inlet valve is a one-way valve and in one embodiment, the one-way valve is a duckbill check valve which is effective at creating a tight seal when closed despite communicating with the abrasive particulate material.




In one embodiment, an adjustable control valve is provided in-line in the first flow path before the inlet valve to set a desired flow rate of pressurized gas supplied to the inlet valve. In one embodiment, a first check valve is provided in-line in the second flow path before the first flow path and the third flow path, and a second check valve is provided in-line in the third flow path. In one embodiment, a filter is provided in-line in the third flow path after the second check valve to help keep the abrasive particulate material from back streaming into the second check valve.




In one embodiment, the fourth flow path includes an inlet orifice communicating with the unoccupied portion of the interior space of the storage container to restrict input to the fourth flow path.




In one embodiment, a baffle is positioned within the storage container above the inlet opening to disperse pressurized gas released into the interior space of the storage container so as to more evenly distribute pressurized air throughout a base of the storage container. In one embodiment, a nozzle is provided at an output end of the fifth flow path for accelerating and directing the abrasive particulate material toward a surface to be processed.




Another aspect of the present invention provides a pressurized delivery system for abrasive particulate material. The pressurized delivery system includes an input pressure line having a first end adapted to communicate with a pressurized source of gas, a fluidizing pressure line having a first end communicating with the input pressure line, and a storage container adapted to contain the abrasive particulate material therein. An inlet valve communicates with a second end of the fluidizing pressure line and an inlet opening of the storage container. A back-pressure pressure line has a first end communicating with an unoccupied portion of an interior space of the storage container, and an output pressure line has a first end communicating with a second end of the input pressure line, a second end of the back-pressure pressure line, and an outlet opening of the storage container. As such, a pressurized supply of the abrasive particulate material may be formed and delivered through the output pressure line.




Another aspect of the present invention provides a method of delivering abrasive particulate material under pressure from a storage container adapted to contain the abrasive particulate material therein. The method includes the steps of communicating an inlet valve with an inlet opening of the storage container and supplying a first gas, regulated to a first predetermined pressure, to the inlet valve. The first gas is released through the inlet valve and into the storage container, and a quantity of the abrasive particulate material is discharged through an outlet opening of the storage container to an output junction. In addition, a second gas, regulated to a second predetermined pressure, is supplied to the output junction. As such, a pressurized supply of the abrasive particulate material is formed and delivered through the output junction.




Another aspect of the present invention provides a method of abrading a portion of a silicon substrate. The method includes the steps of fluidizing abrasive particulate material with a first gas within a storage container, combining the gas fluidized abrasive particulate material with a stream of a second gas to provide a stream of the gas fluidized abrasive particulate material, and directing the stream of the gas fluidized abrasive particulate material at the silicon substrate to abrade the portion of the silicon substrate.




Another aspect of the present invention provides a method of forming an ink fill slot in a silicon substrate of an ink-jet printhead. The method includes the steps of fluidizing abrasive particulate material with a first gas within a storage container, combining the gas fluidized abrasive particulate material with a stream of a second gas to provide a stream of the gas fluidized abrasive particulate material, and directing the stream of the gas fluidized abrasive particulate material at the silicon substrate to form the ink fill slot in the silicon substrate.




Another aspect of the present invention provides an ink-jet printhead including a silicon substrate having an ink fill slot formed therein by fluidizing abrasive particulate material with a first gas within a storage container, combining the gas fluidized abrasive particulate material with a stream of a second gas to provide a stream of the gas fluidized abrasive particulate material, and directing the stream of the gas fluidized abrasive particulate material at the silicon substrate to form the ink fill slot in the silicon substrate.




The present invention provides a system for delivering abrasive particulate material under pressure such that more accurately metered flow of the abrasive particulate material from a storage container, through a metering orifice, and into an output pressure line is achieved. More particularly, the present invention provides a method for more uniformly forming an ink fill slot in a silicon substrate of an inkjet printhead.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic view of a pressurized delivery system for abrasive particulate material according to the present invention;





FIG. 2

is an enlarged view of a portion of

FIG. 1

illustrating portions of the pressurized delivery system including an inlet valve in an opened state;





FIG. 3

is an enlarged view of a portion of

FIG. 1

illustrating portions of the pressurized delivery system including an inlet valve in a closed state;





FIG. 4

is a perspective view of a portion of an ink-jet printhead including an ink fill slot formed in a silicon substrate by a pressurized delivery system according to the present invention;





FIG. 5

is a top view of a portion of an ink-jet printhead including a plurality of printing elements formed on a silicon substrate and an ink fill slot formed in the silicon substrate by a pressurized delivery system according to the present invention; and





FIG. 6

is a cross-sectional view of an ink fill slot formed in a silicon substrate by a pressurized delivery system according to the present invention.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.





FIG. 1

illustrates one embodiment of a pressurized delivery system


10


for abrasive particulate material


12


according to the present invention. Pressurized delivery system


10


includes a storage container


20


, an input pressure line


30


, a fluidizing pressure line


40


, an inlet valve


50


, a back-pressure pressure line


60


, and an output pressure line


70


. Storage container


20


defines an interior space


22


adapted to contain abrasive particulate material


12


therein. When abrasive particulate material


12


is deposited within storage container


20


, an occupied portion


22




a


and unoccupied portion


22




b


of interior space


22


are defined. Unoccupied portion


22




b


includes a portion of interior space


22


devoid of abrasive particulate material


12


. Abrasive particulate material


12


may include sand, aluminum oxide, silicon carbide, quartz, diamond dust, or any other suitable abrasive material in particulate form or particulate material having suitable abrasive qualities for a desired application of pressurized delivery system


10


.




In one embodiment, storage container


20


is generally cylindrical in shape and includes a base


24


having an inlet opening


26


and an outlet opening


28


defined therein. Outlet opening


28


functions as a metering orifice through which abrasive particulate material


12


is fed to output pressure line


70


. In one embodiment, inlet opening


26


is adjacent to outlet opening


28


and a baffle


25


is provided above inlet opening


26


. In addition, base


24


of storage container


20


includes a bottom wall


24




a


, in which inlet opening


26


and outlet opening


28


are formed, and an inwardly, downwardly sloping side wall


24




b


. Inwardly, downwardly sloping side wall


24




b


facilitates gravity flow of abrasive particulate material


12


downward within storage container


20


toward outlet opening


28


.




Input pressure line


30


has a first end


32


and a second end


34


. First end


32


of input pressure line


30


is adapted to communicate with a pressurized source of gas


14


. Second end


34


of input pressure line


30


communicates with an output junction


76


of output pressure line


70


. In one embodiment, the gas is air delivered by a pressure regulating system


16


. In an alternate embodiment, the gas includes an inert gas, such as argon. Use of inert gas may be preferred, for example, when a material to be processed with pressurized delivery system


10


is sensitive to air and oxidation of the material is a concern. For clarity, the following description only refers to using pressurized air, but it is understood that use of other gases, or combinations of gases, is within the scope of the present invention.




In one embodiment, a series of check valves are provided in input pressure line


30


. The check valves include a low-pressure check valve


37


and a resister check valve


38


. In addition, a filter


39


is provided in-line in input pressure line


30


after resister check valve


38


. Filter


39


helps keep abrasive particulate material


12


from back streaming into resister check valve


38


. An example of such a filter is a 9071-20-⅛, 25 micron filter manufactured by Arrow.




Low-pressure check valve


37


is provided in-line in input pressure line


30


to prevent back flow from storage container


20


into pressure regulating system


16


if a pressure drop occurs. Low-pressure check valve


37


has a low cracking pressure, for example, ⅓ pounds per square inch (psi), to reduce overall pressure drop in the system. An example of such a check valve is a SS-6C-⅓ check valve manufactured by Nupro. Resister check valve


38


is provided in-line in input pressure line


30


after low-pressure check valve


37


. Resister check valve


38


produces a fairly constant pressure drop equal to its cracking pressure, for example, 10 psi. An example of such a check valve is a 4M-C4L-10-B check valve manufactured by Parker.




Resister check valve


38


develops a pressure in both input pressure line


30


, between low-pressure check valve


37


and resister check valve


38


, and fluidizing pressure line


40


which is higher than a pressure in input pressure line


30


after resister check valve


38


. As such, a higher regulated pressure is developed before resister check valve


38


and a lower regulated pressure is developed after resister check valve


38


. This higher pressure, before resister check valve


38


, produces a drive pressure for fluidizing pressure line


40


. A benefit of resister check valve


38


is that it automatically produces a fairly constant pressure drop regardless of output pressure settings. In an alternate embodiment, a first pressure regulator (not shown) is provided in-line in input pressure line


30


before fluidizing pressure line


40


and a second pressure regulator (not shown) is provided in-line in input pressure line


30


after fluidizing pressure line


40


. The first and second pressure regulators, however, must each be adjusted in response to output pressure setting changes to develop the desired pressure drop within input pressure line


30


for producing drive pressure for fluidizing pressure line


40


.




Fluidizing pressure line


40


has a first end


42


and a second end


44


. First end


42


of fluidizing pressure line


40


communicates with an input junction


36


provided in input pressure line


30


between low-pressure check valve


37


and resister check valve


38


. Second end


44


of fluidizing pressure line


40


communicates with inlet valve


50


. As such, fluidizing pressure line


40


provides a by-pass flow path which is in parallel flow with input pressure line


30


from input junction


36


. In one embodiment, a control valve


46


is provided in-line in fluidizing pressure line


40


before inlet valve


50


. Control valve


46


is an adjustable valve used to set a desired flow rate, referred to as a fluidizing flow rate, of pressurized air supplied to inlet valve


50


. An example of such a control valve is a MNV-1K needle valve manufactured by Clippard.




Inlet valve


50


communicates with fluidizing pressure line


40


on an input side


52


(

FIG. 2

) and inlet opening


26


of storage container


20


on an output side


54


(FIG.


2


). Inlet valve


50


has an opened state, illustrated in

FIG. 2

, and a closed state, illustrated in

FIG. 3

, depending on an operational state of pressurized delivery system


10


. Inlet valve


50


is a one-way valve that permits substantially no flow in an upstream direction while permitting flow only in a downstream direction from fluidizing pressure line


40


to storage container


20


. In one embodiment, inlet valve


50


is made of a flexible material, for example, rubber, and is commonly referred to as a flapper, or duckbill, check valve. The duckbill check valve is effective at creating a tight seal when closed despite communicating with abrasive particulate material


12


. An example of such a check valve is a VL1490-102 check valve manufactured by Vernay Laboratories.




In an alternate embodiment, inlet valve


50


is a porous material (not shown) that permits air to flow from fluidizing pressure line


40


to storage container


20


, but does not permit abrasive particulate material


12


to flow into fluidizing pressure line


40


. The porous material suitably includes natural stones, micro-screen, filter cloth, or similar performing material. An example of such a material is a macroporous material formed of nylon and having a mesh opening of 8 microns manufactured by Spectrum.




Back-pressure pressure line


60


has a first end


62


and a second end


64


. First end


62


of back-pressure pressure line


60


communicates with unoccupied portion


22




b


of interior space


22


of storage container


20


. Second end


64


of back-pressure pressure line


60


communicates with output junction


76


of output pressure line


70


. An inlet orifice


66


is provided at first end


62


of back-pressure pressure line


60


and has a diameter less than that of back-pressure pressure line


60


. As such, inlet orifice


66


restricts input of air into back-pressure pressure line


60


and reduces sensitivity of the system to differing levels of abrasive particulate material


12


contained within storage container


20


. It is theorized that back-pressure created by inlet orifice


66


increases a head on outlet opening


28


so that a head created by abrasive particulate material


12


itself is not the sole contributor to flow of abrasive particulate material


12


through outlet opening


28


. Thus, variation of flow caused by differing levels of abrasive particulate material


12


within storage container


20


is reduced.




Output pressure line


70


has a first end


72


and a second end


74


. First end


72


of output pressure line


70


communicates with second end


34


of input pressure line


30


, second end


64


of back-pressure pressure line


60


, and outlet opening


28


of storage container


20


at output junction


76


. An abrasive pinch


77


is provided in output pressure line


70


and a vent pinch


78


is provided in a vent tube


79


communicating with output pressure line


70


before abrasive pinch


77


. In addition, a nozzle


80


is provided at second end


74


of output pressure line


70


. Nozzle


80


accelerates and directs abrasive particulate material


12


toward a surface to be processed. Abrasive pinch


77


and vent pinch


78


are used during operation of pressurized delivery system


10


, as is known in the art.




In use, abrasive particulate material


12


is disposed within interior space


22


of storage container


20


to a level such that first end


64


of back-pressure pressure line


60


communicates with unoccupied portion


22




b


of interior space


22


. In one illustrative embodiment, abrasive particulate material


12


is aluminum oxide. Pressurized air


14


is regulated and supplied, by pressure regulating system


16


, to first end


32


of input pressure line


30


, and first end


42


of fluidizing pressure line


40


after passing through low-pressure check valve


37


. To operate pressurized delivery system


10


, abrasive pinch


77


is opened, as illustrated in FIG.


1


. Resister check valve


38


, however, remains closed until a predetermined pressure differential, for example, 10 psi, occurs across resister check valve


38


. This develops higher pressure before resister check valve


38


and produces drive pressure for fluidizing pressure line


40


. When the predetermined pressure differential does occur across resister check valve


38


, pressurized air


14


is released through resister check valve


38


and through filter


39


to output junction


76


.




During operation, control valve


46


is adjusted to establish a desired fluidizing flow rate of pressurized air


14


to inlet valve


50


. In one illustrative embodiment, with a standardized pressure of 4 psi, the fluidizing flow rate is adjusted to 6.0 standard cubic feet per hour (SCFH). The flow of pressurized air


14


causes inlet valve


50


to open, as illustrated in FIG.


2


. As such, pressurized air


14


, referred to as a fluidizing air stream, is released into interior space


22


of storage container


20


, through inlet opening


26


. Thereafter, baffle


25


disperses, or spreads out, pressurized air


14


released into interior space


22


of storage container


20


so as to more evenly distribute pressurized air


14


throughout base


24


of storage container


20


. Since outlet opening


28


is adjacent to inlet opening


26


, abrasive particulate material


12


adjacent outlet opening


28


is “fluidized.” Essentially, abrasive particulate material


12


adjacent outlet opening


28


develops a fluidic trait and, as such, is maintained flowable through outlet opening


28


. Thus, abrasive particulate material


12


is more accurately metered as it flows consistently through outlet opening


28


and to output junction


76


where it joins pressurized air


14


released through resister check valve


38


.




While abrasive particulate material


12


flows through outlet opening


28


, a portion of the fluidizing air stream released into storage container


20


by inlet valve


50


is released through outlet opening


28


and to output junction


76


with abrasive particulate material


12


. A portion of the fluidizing air stream released into storage container


20


by inlet valve


50


also permeates through abrasive particulate material


12


to unoccupied portion


22




b


of interior space


22


where it is vented through back-pressure pressure line


60


to output junction


76


. As such, abrasive particulate material


12


and the portion of the fluidizing air stream released through outlet opening


28


with abrasive particulate material


12


, pressurized air


14


released through resister check valve


38


, and the portion of the fluidizing air stream vented through back-pressure pressure line


60


, come together at output junction


76


to form a pressurized abrasive particulate material/air mixture


18


. As such, pressurized abrasive particulate material/air mixture


18


is supplied to output pressure line


70


. Thereafter, pressurized abrasive particulate material/air mixture


18


is accelerated through nozzle


80


.




To discontinue operation, or develop a stand-by state, of pressurized delivery system


10


, abrasive pinch


77


is closed. With abrasive pinch


77


closed, pressurized air


14


no longer flows through pressurized delivery system


10


. Inlet valve


50


, therefore, returns to the closed state, as illustrated in FIG.


3


. Thus, a static mode of pressurized delivery system


10


is established.




Referring to

FIGS. 4-6

, one illustrative application of pressurized delivery system


10


is for forming an ink fill slot


122


in a silicon substrate


120


of an ink-jet printhead


100


for an ink-jet printer (not shown).

FIG. 4

illustrates a portion of ink-jet printhead


100


including a printing, or drop ejecting, element


110


formed on substrate


120


. Ink fill slot


122


, formed in substrate


120


, provides a supply of ink (not shown) to a plurality of printing elements


110


as illustrated in FIG.


5


. Although

FIG. 5

illustrates one common configuration of a plurality of printing elements


110


including two parallel rows of printing elements


110


along ink fill slot


122


, other configurations of printing elements


110


employed in ink-jet printers, including approximately circular and single row configurations, are within the scope of the present invention.




As illustrated in

FIG. 4

, printing element


110


includes a layer


112


having an ink feed channel


113


formed therein, a resistor


116


positioned within ink feed channel


113


, and a nozzle plate


118


having a nozzle


119


formed therein. Ink feed channel


113


forms a drop ejection chamber


115


surrounding resistor


116


on three sides. Ink (not shown) is supplied from ink fill slot


122


to drop ejection chamber


115


through a pair of opposed projections


114


provided at an entrance to ink feed channel


113


. Nozzle


119


is operatively associated with resistor


116


such that droplets of ink are ejected through nozzle


119


(e.g., normal to the plane of resistor


116


) and toward a print medium (not shown) upon heating of a quantity of ink by resistor


116


. As such, alphanumeric characters and graphics are formed on the print medium (not shown).




As illustrated in

FIG. 6

, substrate


120


has a first surface


124


and a second surface


126


upon which printing element


110


is formed. Second surface


126


is opposed to and substantially parallel with first surface


124


. In one embodiment, substrate


120


comprises a single crystal silicon wafer, commonly used in the microelectronics industry. In addition, ink fill slot


122


communicates with both first surface


124


and second surface


126


, and converges from first surface


124


toward second surface


126


. As such, ink fill slot


122


provides a supply of ink (not shown) to second surface


126


and, therefore, printing element


110


.




In accordance with the present invention, pressurized delivery system


10


is used to form ink fill slot


122


in silicon substrate


120


by directing a stream of pressurized abrasive particulate material/air mixture


18


at first surface


124


of silicon substrate


120


. The stream of pressurized abrasive particulate material/air mixture


18


is directed at first surface


124


at least until ink fill slot


122


communicates with second surface


126


of silicon substrate


120


. Since ink fill slot


122


provides the supply of ink to printing element


110


during the printing process, printing performance depends on uniformity of ink fill slot


122


. A distance from an edge of ink fill slot


122


to drop ejection chamber


115


, for example, determines how rapidly drop ejection chamber


115


can refill with ink after ink is ejected from drop ejection chamber


115


during the printing process. How rapidly drop ejection chamber


115


can refill with ink, in turn, effects a frequency of operation of printing element


110


and, therefore, printing speed. Compared with existing sandblasting systems employed for forming ink fill slot


122


, pressurized delivery system


10


has been shown to significantly reduce size and shape variations of ink fill slot


122


.




While pressurized delivery system


10


has been described and illustrated for use in forming ink fill slot


122


in silicon substrate


120


of ink-jet printhead


100


with pressurized abrasive particulate material/air mixture


18


, it is apparent that pressurized delivery system


10


is useful for other cleaning, polishing, abrading or related operations. Other example embodiments of pressurized delivery system


10


are employed for removing paint, rust, or other foreign materials from surfaces including metal, concrete, or the like, cleaning or polishing jewelry or corroded articles, and/or abrading or polishing steel or other metal components.




Fluidizing pressure line


40


supplies pressurized air


14


to storage container


20


so as to fluidize a quantity of abrasive particulate material


12


contained therein. As such, abrasive particulate material


12


flows consistently through outlet opening


28


of storage container


20


to join pressurized air


14


supplied to output pressure line


70


. Pressurized delivery system


10


, therefore, provides a system for delivering abrasive particulate material under pressure such that more accurately metered flow of the abrasive particulate material from a storage container, through a metering orifice, and into an output pressure line is achieved.




Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations calculated to achieve the same purposes may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. Those with skill in the chemical, mechanical, electro-mechanical, electrical, and computer arts will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This application is intended to cover any adaptations or variations of the preferred embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.



Claims
  • 1. A pressurized delivery system for abrasive particulate material, the pressurized delivery system comprising:a storage container defining an interior space adapted to contain the abrasive particulate material therein, the storage container including a base having an inlet opening and an outlet opening defined therein; an inlet valve communicating with the inlet opening; a first flow path communicating with the inlet valve; a second flow path communicating with the first flow path and adapted to communicate with a pressurized source of gas; a third flow path communicating with the second flow path; a fourth flow path communicating with an unoccupied portion of the interior space of the storage container; and a fifth flow path communicating with the third flow path, the outlet opening, and the fourth flow path.
  • 2. The pressurized delivery system of claim 1, wherein the third flow path is in parallel flow with the first flow path from the second flow path.
  • 3. The pressurized delivery system of claim 1, wherein the abrasive particulate material includes at least one of sand, aluminum oxide, silicon carbide, quartz, and diamond dust.
  • 4. The pressurized delivery system of claim 1, wherein the gas is air.
  • 5. The pressurized delivery system of claim 1, wherein the gas is an inert gas.
  • 6. The pressurized delivery system of claim 1, wherein the inlet valve is a one-way valve.
  • 7. The pressurized delivery system of claim 6, wherein the one-way valve is a duckbill check valve.
  • 8. The pressurized delivery system of claim 1, further comprising:an adjustable control valve provided in-line in the first flow path before the inlet valve.
  • 9. The pressurized delivery system of claim 1, further comprising:a first check valve provided in-line in the second flow path before the first flow path and the third flow path; and a second check valve provided in-line in the third flow path.
  • 10. The pressurized delivery system of claim 9, further comprising:a filter provided in-line in the third flow path after the second check valve.
  • 11. The pressurized delivery system of claim 1, wherein the fourth flow path includes an inlet orifice communicating with the unoccupied portion of the interior space of the storage container, the inlet orifice restricting input to the fourth flow path.
  • 12. The pressurized delivery system of claim 1, further comprising:a baffle positioned within the storage container above the inlet opening.
  • 13. The pressurized delivery system of claim 1, further comprising:a nozzle provided at an output end of the fifth flow path.
  • 14. A pressurized delivery system for abrasive particulate material, the pressurized delivery system comprising:an input pressure line having a first end and a second end, the first end adapted to communicate with a pressurized source of gas; a fluidizing pressure line having a first end and a second end, the first end of the fluidizing pressure line communicating with the input pressure line intermediate the first and second ends of the input pressure line; an inlet valve communicating with the second end of the fluidizing pressure line; a storage container defining an interior space adapted to contain the abrasive particulate material therein, the storage container including a base having an inlet opening and an outlet opening defined therein, the inlet opening communicating with the inlet valve; a back-pressure pressure line having a first end and a second end, the first end of the back-pressure pressure line communicating with an unoccupied portion of the interior space of the storage container; and an output pressure line having a first end and a second end, the first end of the output pressure line communicating with the second end of the input pressure line, the second end of the back-pressure pressure line, and the outlet opening of the storage container.
  • 15. The pressurized delivery system of claim 14, wherein a portion of the input pressure line is in parallel flow with the fluidizing pressure line.
  • 16. The pressurized delivery system of claim 14, wherein the abrasive particulate material includes at least one of sand, aluminum oxide, silicon carbide, quartz, and diamond dust.
  • 17. The pressurized delivery system of claim 14, wherein the gas is air.
  • 18. The pressurized delivery system of claim 14, wherein the gas is an inert gas.
  • 19. The pressurized delivery system of claim 14, wherein the inlet valve is a one-way valve.
  • 20. The pressurized delivery system of claim 19, wherein the one-way valve is a duckbill check valve.
  • 21. The pressurized delivery system of claim 14, further comprising:an adjustable control valve provided in-line in the fluidizing pressure line before the inlet valve.
  • 22. The pressurized delivery system of claim 14, further comprising:a first check valve provided in-line in the input pressure line before the fluidizing pressure line; and a second check valve provided in-line in the input pressure line after the fluidizing pressure line.
  • 23. The pressurized delivery system of claim 22, further comprising:a filter provided in-line in the input pressure line after the second check valve.
  • 24. The pressurized delivery system of claim 14, wherein the back-pressure pressure line includes an inlet orifice communicating with the unoccupied portion of the interior space of the storage container, the inlet orifice restricting input to the back-pressure pressure line.
  • 25. The pressurized delivery system of claim 14, further comprising:a baffle positioned within the storage container above the inlet opening.
  • 26. The pressurized delivery system of claim 14, further comprising:a nozzle provided at the second end of the output pressure line.
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