Abstract:
A piping assembly for a compressed air assembly and a method of forming the piping assembly. The piping assembly comprises hollow aluminum tubing having first and second ends. First and second threaded connector members associated with first and second compressed air assembly components. A compression fitting is associated with each end of the aluminum tubing and each compression fitting is configured to sealingly engage a respective one of the threaded connector members.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 60/228,754 filed Aug. 30, 2000. 
     
    
     
       BACKGROUND  
         [0002]    The present invention relates to air compressors. More particularly, the present invention relates to an air compressor piping system and a method of interconnecting compressed air components.  
           [0003]    Historically, compressed air systems have used iron or steel pipe with threaded pipe and fitting members to transport fluid to the point of use. When installing these systems, pipes frequently need to be cut to a custom length and threaded with special tooling. Furthermore, special sealants are often required in joining the threaded pipe to the fittings to make the joint pressure tight. Alternative systems have been made from copper pipe, which typically uses soldered joints, or stainless steel pipe which may require welding. All this work greatly increases the installation time and resources needed to assemble the compressed air system piping.  
           [0004]    Over time, the iron, steel and copper pipes typically corrode. Such corrosion often results in a loss of air flow and increased pressure drops. Additionally, corrosion debris can loosen and flow downstream into compressed air components thus contaminating the system and causing potential problems to filters, tools, and other equipment.  
         SUMMARY  
         [0005]    The present invention relates to a piping assembly for a compressed air assembly. The piping assembly comprises at least a first length of hollow aluminum tubing having first and second ends. A first threaded connector member is adapted to be associated with a first compressed air assembly component and a second threaded connector member is adapted to be associated with a second compressed air assembly component. A compression fitting is associated with each end of the aluminum tubing. Each compression fitting is configured to sealingly engage a respective one of the threaded connector members.  
           [0006]    A method of interconnecting members of a compressed air system and a method of forming a piping assembly for a compressed air system are also provided. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a schematic drawing illustrating a compressed air system utilizing the piping system of the present invention.  
         [0008]    [0008]FIG. 2 is a side elevational view of a portion of piping of the present invention.  
         [0009]    [0009]FIG. 3 is an end view of the piping of the present invention along the line  3 - 3  in FIG. 2.  
         [0010]    [0010]FIG. 4 is an isometric view of an illustrative pipe bender usable with the preferred piping of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]    Referring to FIG. 1, an illustrative compressor system  10  incorporating a piping system  50  that is a preferred embodiment of the present invention is shown. The illustrated compressor system  10  includes, for example, a compressor  12 , a compressed air storage tank  14 , a distribution block  16  for connecting point of use components and a downstream line  18 . Other compressor system components may also be used together with or in place of any or all of the illustrated components. The compressor components  12 - 18  are interconnected utilizing the preferred piping system  50 . The piping system  50  includes round aluminum piping  52 , various threaded connectors  54 - 58  and a plurality of compression fittings  60 .  
         [0012]    The threaded connectors  54 - 58  can be of numerous configurations. While the system is not limited to the illustrated connectors, the illustrated connectors are briefly described. Unions  54  can be utilized for joining two lengths of piping. A suitable union is available from Ingersoll-Rand Company under part no. 54563861. Straight male studs  56  are generally utilized to interconnect a length of piping to one of the compressor components. A suitable straight male stud is available from Ingersoll-Rand Company under part no. 54563895. Tee unions  58  are utilized to split the piping into multiple branches. A suitable tee union is available from Ingersoll-Rand Company under part no. 54563960. Other connectors, for example, 45° and 90° elbows, may also be used. Additionally, mounting brackets  20  and the like may be utilized to support the piping  52  between the various components.  
         [0013]    The piping  52  is interconnected to the threaded connectors  54 - 58  using compression fittings  60 . The preferred compression fittings  60  include a compression nut  62  and a ferrule  64 . The piping  52  is inserted into the respective connector  54 - 58  and the compression nut  62  is tightened over the ferrule  64 . As the nut  62  is tightened, the ferrule  64  is pressed into the connector  54 - 58 , causing the ferrule  64  to compress against the piping  52  and the compression nut  62 , thereby providing a fluid tight connection. The ferrules  64  may be, but do not have to be, of the bite type. The piping  52  does not require any special preparation, for example, threading, etching or the like, prior to connection. The piping  52  is simply cut to a desired length such that it can be positioned into the desired connector. Additionally, the compression seal created between the ferrule  64 , piping  52  and connector  54 - 58  is extremely reliable and leak free without the use of additional material and process steps (i.e.: applying sealant to threads, soldering, welding, etc.). The fitting materials are chosen to address environmental considerations, for example, thermal expansion, mechanical strength, and atmospheric &amp; galvanic corrosion resistance. A preferred fitting material is nickel plated brass.  
         [0014]    Referring to FIGS. 2 and 3, the preferred piping  52  will be described. The preferred piping  52  is round extruded aluminum tubing. The ductile nature of the aluminum tubing allows the piping  52  to be bent as necessary to accommodate the configuration of a given compressed air assembly  10 . The malleable and ductile nature of the aluminum allows the piping  52  to be bent utilizing a pipe bender  100 , similar to that shown if FIG. 4, or the like into many smooth radius shapes R, thereby minimizing the need for various types of elbow fittings. Reducing the number of elbow type fittings allows for quicker installation and minimizes the number of potential leak points. The extrusion and the smooth radius bends leave an extremely smooth, continuous surface finish that minimizes the flow losses and pressure drops of the compressed air.  
         [0015]    While a ductile tubing is desired, the piping  52  must also have sufficient strength to withstand the forces associated with the compressed air pressure. To provide such, the extruded aluminum tubing is age hardened utilizing a thermal or chemical treatment to increase the strength and hardness of the tubing. The aluminum material and age hardening process are chosen such that the tubing has sufficient strength while maintaining a desired degree of ductility. Many combinations of material and hardening can be utilized to balance these desired attributes. A preferred material and treatment is 6063-T4 as recognized under the Aluminum Association standards, the 6063 designating a specific mixture of aluminum, magnesium and silicon and the T4 designating a solution heat-treated and naturally aged hardening process. One inch tubing manufactured with these parameters and having a 22 mm outside diameter and a wall thickness of approximately 1.5 mm has been found to support working air pressures of at least 250 psi and to permit a smooth 180° bend with an inside radius of 75 mm. Other piping sizes may also be used. The piping  52  is preferably manufactured such that the tubing is bendable to 180° with a minimum bend radius less than four times the outside diameter of the tubing.  
         [0016]    To further enhance the piping performance, the preferred piping  52  is anodized along the inside and outside surfaces. The aluminum is immersed in an acid electrolyte bath through which an electrical current is passed. This causes a coating of aluminum oxide  70  to grow on the internal and external surfaces of the aluminum tubing. The coating thickness and surface characteristics can be controlled to meet a desired level of corrosion resistance. The preferred anodization standard is Aluminum Association specification AA-MM32 C11 C22 A213, the MM32 designating a directional sanding, the C11 and C22 designating a chemical degreasing and a medium matte etched finish, and the A213 indicating a film thickness of 0.0003 inches. The aluminum oxide  70  created by the anodizing provides a first, primary boundary of corrosion resistance for the piping  52 . Additionally, the aluminum material has a natural corrosion resistance that provides a secondary boundary of corrosion resistance. In an Accelerated Environmental Test performed by Applied Technical Services, Incorporated utilizing a salt spray under method ASTM B117-97, piping manufactured in accordance with the above anodization standard showed no corrosion after  1100  hours while common commercial black steel pipe showed severe red rust after  250  hours under the same conditions.  
         [0017]    The piping assembly  50  of the present invention provides piping  52  having a smooth, corrosion resistant surface finish that minimizes flow losses and pressure drops. Additionally, the piping assembly allows extremely reliable, fast and versatile piping configurations.