Abstract:
A fluid cooling system and associated fitting assembly for an electronic component such as a multi-processor computer offer easy and reliable connect and disconnect operations while doing so in a minimum amount of available space without damaging associated components of an electronic device, computer or cooling system. One exemplary fitting assembly includes a manifold mount with a port that is in fluid communication with a manifold tube. A fitting is sized and configured to mate with the port and is in fluid communication with associated cooling tubes of a cold plate. A latch is pivotally mounted to the manifold mount for movement to and between a first position in which the latch secures the fitting to the manifold mount and a second position in which the fitting is capable of being disconnected from the manifold mount.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/917,977, filed on Nov. 2, 2010 by Jason R. Eagle (now issued as U.S. Pat. No. 8,456,833), the entire disclosure of which is incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to cooling of electronic components and more particularly to a fitting for coupling tubes containing cooling fluid to a fluid manifold system. 
     BACKGROUND OF THE INVENTION 
     Since the development of electronic digital computers, efficient removal of heat has played a key role in insuring the reliable operation of successive generations of computers. In many instances the trend toward higher circuit packaging density to provide reductions in circuit delay time (i.e., increased speed) has been accompanied by increased power dissipation requirements. 
     One approach to cooling such electronic components was to utilize hybrid air-to-water cooling in otherwise air-cooled machines to control cooling air temperatures. With the precipitous rise in both chip and module powers that occurred throughout the 1980s, it was determined that the most effective way to manage chip temperatures in multichip modules was through the use of indirect water-cooling. 
     The increased use of complementary metal oxide semiconductor (CMOS) based circuit technology in the early 1990s led to a significant reduction in power dissipation and a return to totally air-cooled machines. However, this was but a brief respite as power and packaging density rapidly increased, first matching and then exceeding the performance of the earlier machines. These increases in packaging density and power levels have resulted in unprecedented cooling demands at the package, system and data center levels, leading to a return of water cooling. 
     Many large scale computing systems contain multiple dual core processor modules, often as many as 16 or more. An assembly of an equal number of cold plates is often used to cool the processors. The assembly in one prior system consists of the cold plates (one cold plate for each processor module), tubing that connects groups of cold plates in series, tubing that connects each grouping of cold plates, or quadrant, to a common set of supply and return lines, and two hoses that connect to system level manifolds in the rack housing the processor modules or nodes. 
     The ability to remove a node from the liquid cooling system without adversely affecting the operation of the remaining system is provided by fluid couplers that can be uncoupled quickly and easily with virtually no liquid leakage (i.e. “quick connects”). 
     However, due to the ever increasing demand for computing capacity and often limited available space, more processor nodes are placed in closer proximity to one another with less and less available free space for the cooling systems. As such, known quick connect fittings used in prior cooling systems often do not fit in the allocated space. Other than known quick connect fittings, other options use a nut to seal either an  0 -ring, or a compression ring that pinches the tubing to make a seal. These connectors are often not feasible due to the extreme size of the components and the fact that there is no available tool or wrench clearance to connect and disconnect these types of fitting. Additionally, tightening these types of fittings produces a high torque on the delicate brazed tube assembly connected to the cold plates. The twisting torque could damage tubing, or put stress on electronic modules that the cold plates interface with. 
     Therefore, an improved fitting assembly that overcomes these problems in the prior art while still offering durable and reliable connect and disconnect operations in a minimum of available space is needed. 
     SUMMARY OF THE INVENTION 
     According to various embodiments, this invention includes a fluid cooling system for an electronic component, the electronic component with a fluid cooling system and a fitting assembly for use in a fluid cooling system for an electronic component that overcomes the above described problems and others in the prior art. 
     In one embodiment, this invention includes a cooling system for an electronic component, such as a multi-processor computer including a number of cold plates each cooling one of the processors using a cooling medium. Cooling tubes are each routed through one of the cold plates to carry the liquid cooling medium there through. A manifold assembly has a manifold tube in communication with each of the cooling tubes to transmit the liquid cooling medium to and from each of the cold plates. A number of fitting assemblies connect the various cooling tubes to the manifold assembly. In one embodiment, each fitting assembly includes a manifold with the manifold tube passing there through. A port in the manifold is in fluid communication with the manifold tube. A fitting is sized and configured to mate with the port and is in fluid communication with the associated cooling tubes of one of the cold plates. A latch is pivotally mounted to the manifold mount for movement to and between a first position in which the latch secures the fitting to the manifold mount and a second position in which the fitting is capable of being connected and disconnected from the manifold. 
     In one embodiment, the latch is generally U-shaped with a pair of legs each extending from a central portion of the latch and the legs are pivotally coupled to opposite sides of the manifold. The central portion of the latch captures the fitting onto the manifold when the latch is in the first position. The fitting assembly may include a load screw threadably inserted through the central portion of the latch to engage the fitting when the latch is in the first position to thereby secure the fitting to the manifold. In one embodiment, a longitudinal axis of the load screw is aligned with a longitudinal axis of the port when the latch is in the first position to align the holding force of the fitting with the manifold. A bearing plate may be mounted on the fitting and positioned to be engaged by the load screw when the latch is in the first position to thereby alleviate stress and avoid damage to the fitting. A pair of spaced channels may be formed on opposite sides of the fitting to assist in installation and removal of the fitting relative to the manifold. The same fitting assembly design according to one embodiment of this invention may be utilized for either the supply side of the cooling fluid medium for the cold plate or the return side of the cooling fluid medium for the cold plate. 
     The invention in various embodiments includes a fluid cooling system for electronic components such as computers, electronic components or computers with a fluid cooling system and a fitting assembly for use in such environments. The fitting assembly provides the advantages of offering easy and reliable connect and disconnect operations while doing so in a minimum amount of available space without the need for extensive tool operation space or damaging the associated components of the electronic device, computer or cooling system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a cooling system for a number of electronic components according to one embodiment of this invention; 
         FIG. 2  is an enlarged view similar to  FIG. 1  showing a fitting assembly coupled to a manifold of the cooling system; 
         FIG. 3A  is an enlarged view of the fitting assembly of  FIGS. 1-2  partially disassembled; 
         FIG. 3B  is a view similar to  FIG. 3A  with the fitting assembly in a substantially assembled configuration; 
         FIG. 4  is a cross-sectional view taken along line  4 - 4  of  FIG. 3B  of the fitting assembly; and 
         FIG. 5  is a schematic drawing of an exemplary electronic component and associated fluid cooling system in which the fitting of this invention may be used. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments and aspects of this invention are shown in the attached drawings in which  FIG. 5  schematically shows a cooling system  10  for an electronic component  12  such as a computer rack subsystem or the like. The electronic component or computer rack subsystem  12  may include a number of nodes  14 , each of which includes a dual core-processor. During operation of the processors, heat is generated which is dissipated by the cooling system  10  according to various embodiments of this invention. The cooling system  10  according to one embodiment of this invention utilizes a liquid cooling medium  16  such as water, although other liquid cooling mediums may be utilized within the scope of this invention. The cooling medium  16  is supplied to the cooling system  10  via a supply line  18  and extracted from the cooling system  10  via a return line  20 . According to the exemplary cooling system shown in  FIG. 5 , the cooling medium supply line  18  is fed to one of two water conditioning units  22 , although another number of water conditioning units  22  may be utilized. The cooling medium  16  is discharged from the water conditioning units  22  into a supply side manifold assembly  24 . The supply side manifold assembly  24  distributes the cooling medium  16  to a number of cold plates  26  ( FIG. 1 ) which are juxtaposed to the various nodes  14  of the electronic component or computer  12  to thereby cool the associated component via heat transfer to the cooling medium. Any number of nodes may be present in the electronic component  12 . The heated cooling medium  16  is extracted from the cold plates  26  through a return side manifold assembly  25  and processed through a heat exchanger  28 , after which the cooling medium  16  is discharged through the water conditioning units  22  to the return line  20  of the cooling system  10 . As will be appreciated, the exemplary electronic component cooling system  10  shown in  FIG. 5  is for illustration only and other designs of cooling systems, for electronic components or computers may be utilized within the scope of this invention. 
     Referring to  FIGS. 1 and 2 , one embodiment of the cold plate  26  for the node  14  of the electronic component  12  coupled to the cooling system  10  according to this invention is shown. The supply side manifold assembly  24  is shown in  FIG. 1  for simplicity; however, the return side manifold assembly  25  likewise includes the same components and elements as those shown in  FIG. 1  with comparable functions in a return mode as opposed to a supply mode for the cooling fluid medium  16 . The supply side manifold assembly  24  includes dual front end manifold lines  30 ,  32  for the cooling medium  16 , each of which project from a downstream junction block  36 . An upstream junction block  38  has an assembly manifold disconnect fitting  39  through which the fluid cooling medium  16  enters the supply side manifold assembly  24 . A manifold tube  34  extends between the upstream and downstream junction blocks  38 ,  36  of the manifold assembly  24 . Each cold plate  26  shown schematically in  FIGS. 1 and 2  includes first and second cooling tubes  40  each coupled to a fitting assembly  42  mounted on the manifold tube  34 . In one embodiment, the cooling tubes  40  are brazed to a fitting  44  sitting atop the fitting assembly  42  so that the cooling medium  16  may pass from the manifold tube  34  through the fitting assembly  42  and into the cooling tubes  40  of the associated cold plate  26  and to thereby cool the processor node associated with the cold plate  26 . The fitting  44  of each fitting assembly  42  is mounted atop a manifold  46 . The fitting assembly  42  includes a longitudinal passage  48  there through for the manifold tube  34 . According to one embedment of this invention, the fitting  44  is securely retained atop the manifold  46  by a latch  50  pivotally coupled to the manifold  46  which captures the fitting  44  securely on the manifold  46 . As previously noted, the fitting assembly  42  of this invention is readily employed in the supply side manifold assembly  24  as shown in  FIGS. 1-2  as well as the return side manifold assembly  25  ( FIG. 5 ). 
     Referring to  FIGS. 3A-4 , one embodiment of the fitting assembly  42  according to this invention is shown in various configurations. Each fitting assembly generally includes the manifold  46 , the fitting  44 , and the latch  50  in one embodiment. The manifold  46  includes an upper manifold mount  52  having an upper face  54  with a port  56  oriented generally vertically in the manifold  46 . A chassis mount aperture  58  is provided in the lower portion of the manifold  46  for securing the fitting assembly  42  in the electronic component cooling system  10  as appropriate for the supply or return of the cooling fluid medium  16 . The port  56  is in communication with the cooling medium  16  in the manifold tube  34 . The port  56  is sized and configured to receive a downwardly extending projection  60  on the fitting  44  as shown particularly in  FIG. 4 . A main cooling fluid passage  62  extends through the projection  60  and the fitting  44  and is in communication with the cooling tubes  40 , two of which are shown in an upper and lower configuration in the embodiment presented in the drawings. The projection  60  includes an outer annular groove  64  into which is seated a first O-ring  66  which seals the projection  60  against a throat  68  of the manifold  46  as shown in  FIG. 4 . Additionally, a lower flange  70  surrounding the projection  60  on the fitting  44  includes an annular groove  72  in which is seated a second O-ring  74  to seal the fitting against the upper face  54  of the manifold mount  52 . 
     The fitting  44  includes an upper groove  76  sized and configured to receive a bearing plate seated  78  in the groove  76 . The bearing plate  78  has a central seat  80  on its upper face. The bearing plate  78  may be easily installed and adhesively retained in the groove  76  in the fitting  44  as needed. The bearing plate  78  may be selectively removed from the fitting  44  as needed for replacement, repair, repositioning or the like. Pair of undercut channels  82  are each on one opposite faces of the fitting  44 . These channels  82  are available for convenient and secure installation and removal of the fitting onto the manifold  46  without damaging the various components of the system. For example, a tool, such as the jaws of pliers or other device, may be seated within the spaced channels  82  for securely gripping and manipulating the fitting  44  for installation and removal relative to the manifold  46 . 
     The latch  50  is pivotally coupled to the manifold mount  52  as shown generally in  FIGS. 3A-3B . In one embodiment, the latch  50  has a generally inverted U-shape with a pair of legs each extending from a central portion  86  of the latch  50 . A distal end portion of each leg  84  is pivotally coupled to one of two opposite faces of the manifold mount  52 . A pivotal connector, such as a rivet  88  or other device, pivotally secures the leg to the manifold mount. As such, the latch  50  may be pivoted to and between a first position in which the latch  50  captures and overlies the fitting  44  when it is mounted to the manifold mount  52  as shown in  FIG. 3B . In this orientation, the latch  50  extends generally vertically and is aligned with the longitudinal axis  90  of the fitting  44  and the manifold  46 . The latch  50  may be likewise pivoted to a second position as shown in  FIG. 3A  in which the upper face  54  of the manifold mount  52  is exposed and the latch  50  is in generally a horizontal orientation to provide access to the manifold mount  52  and port  56  for installation and removal of the fitting  44 . Naturally, the orientation of the latch  50  in the configuration shown in  FIG. 3A  is opposite from the face of the fitting  44  on which the cooling tubes  40  are joined to the fitting  44  so as to provide access and operation for these components as described. 
     The central portion  86  of the latch  50  includes a threaded hole  92  sized and configured to receive therein a load screw  94 . With the fitting  44  initially seated on the manifold  46  and the projection  60  of the fitting  44  extending into the port  56 , the latch  50  is pivoted into the position shown in  FIG. 3B  with the load screw  94  retracted in the hole  92 . The load screw  94  is threadably advanced through the hole  92  and a terminal end of the load screw  92  contacts the seat  80  on the bearing plate  78 . Continued rotation and advancement of the load screw  94  toward the bearing plate  78  forces the bearing plate  78  and fitting  44  downwardly into a secure and mating relationship with the manifold  46 . The bearing plate  78  distributes the forces delivered by the load screw  94  evenly across the fitting  44  so as to avoid any damage to the fitting  44  which, in one embodiment, is constructed of copper. Moreover, the load screw  94 , bearing plate  78 , fitting projection  60  and port  56  are generally aligned along the longitudinal axis  90  of the fitting assembly  42  as shown generally in  FIG. 4  such that the force delivered by the latch  50  and load screw  94  is axially aligned with the projection  60  of the fitting  44  and the port  56  to provide a secure, stable and reliable connection between the fitting  44  and the manifold  46  for fluid communication of the cooling medium  16  through the assembly. 
     Moreover, the cooling medium  16  flowing through the fitting  44  is inhibited from leaking as a result of the dual O-rings  66 ,  74  on different surfaces between the mating fitting  44  and manifold  46 . In one embodiment, the O-rings  66 ,  74  are positioned on respective sealing surfaces that are not co-planar and, in one embodiment, are orthogonal or perpendicular to one another to form sealing interfaces between the fitting and the manifold mount for enhanced sealing effectiveness. The copper fitting  44  in one embodiment of the cooling system  10  is brazed to the terminal ends of the cooling tubes  40  for reliability during operation of the cooling system  10 . The load delivered by the latch  50  creates a seal along the longitudinal axis  90  as shown in  FIG. 4  in a top-down actuation position as shown in  FIG. 3B . The load screw  94  and latch  50  deliver the load directly along the longitudinal axis  90  and eliminate the need for multiple fasteners as in prior art fitting assemblies. Moreover, the fitting  44  and latch  50  of various embodiments of this invention eliminate the need for tool or wrench clearance in a horizontal, vertical or other orientation to actuate a large nut or other mechanical device and effectuate a sealing engagement between the fitting  44  and manifold  46 . Commonly, two wrenches are required to secure a known fitting assembly to the manifold in a cooling system for an electronic component, one wrench to tighten the fitting and one to keep the assembly from twisting during the tightening motion. The limited space constraints and accessibility of the electronic component and associated cooling system components limit the utility of such prior fitting assemblies for a cooling system. The latch  50  and fitting assembly  42  of various embodiments of this invention offer the direct top-down axial fitting actuation without the need for tool access other than in the axial direction for a screwdriver, Allen wrench or the like for the load screw  94 . Tool access off of the longitudinal axis  90  ( FIG. 4 ) is not required, thereby allowing for tighter and more compact arrangement of the components of the electronic component cooling system  10  according to this invention. The fitting  44  may be manually pushed into the port  56  on the manifold mount  52  and once the O-rings  66 ,  74  seal to the manifold mount  52 , the latch  50  is pivoted into the position shown in  FIG. 3B . The load screw  94  is retracted to provide for clearance when the latch  50  is pivoted from the position shown in  FIGS. 3A  to the position shown in  FIG. 3B . Once in position as in  FIG. 3B , the load screw  94  evenly engage the bearing plate  78  which in one embodiment is stainless steel, on the top of the fitting  44 . The bearing plate  78  prevents debris and excess wear on the copper fitting  44  by the actuation of the load screw  94 . The relatively small contact area of the load screw  94  against the bearing plate  78  along the longitudinal axis  90  of the fitting  44  decouples the screw torque from the remainder of the assembly. This protects the cooling tubes  40  from being damaged and from putting tension on the fitting  44  that could impact proper alignment and positioning of the cooling tubes  40 . The load screw  94  is driven downwardly to a fixed torque that is sufficient to bring the base of the fitting  44  in direct contact with the upper face  54  of the manifold mount  52 . Advantageously, the fitting  44  of this invention provides redundancy because the various mating surfaces and  0 -rings  66 ,  74  between the manifold mount  52  and the fitting  44  are in different planes and proper positioning of the various components can be visually inspected and determined when the fitting  44  is appropriately seated on the manifold mount  52 . 
     Nonetheless, those of ordinary skill in the art may appreciate that based on the principles of this invention that modifications and changes may be made to the embodiments of the invention shown and described herein without departing from the scope of this invention. Therefore, the invention lies in the claims hereinafter appended.