Patent Publication Number: US-7593227-B2

Title: Isolation valve and coolant connect/disconnect assemblies and methods of fabrication for interfacing a liquid cooled electronics subsystem and an electronics housing

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a continuation of U.S. patent application Ser. No. 10/954,792, filed Sep. 30, 2004, and published Mar. 30, 2006, as U.S. Publication No. US-2006-0065874 A1, entitled “Isolation Valve and Coolant Connect/Disconnect Assemblies and Methods of Fabrication for Interfacing a Liquid Cooled Electronics Subsystem and an Electronics Housing” by Campbell et al., which is hereby incorporated herein by reference in its entirety. 

   TECHNICAL FIELD 
   The present invention is directed to cooling assemblies and methods for removing heat from electronic devices and modules. More particularly, this invention relates to an isolation valve assembly for use with a liquid cooled electronics subsystem and associated electronics housing which supplies coolant to the liquid cooled electronics subsystem. Still more particularly, this invention relates to an enhanced connect/disconnect assembly for a thermal dissipation assembly extracting heat from heat generating components of an electronics subsystem disposed operationally within an electronics housing. 
   BACKGROUND OF THE INVENTION 
   As it is well known, as the circuit density of electronic chip devices increases in order to achieve faster and faster processing speeds, there is a correspondingly increasing demand for the removal of heat generated by these devices. The increased heat demand arises both because the circuit devices are packed more closely together and because the circuits themselves are operated at increasingly higher clock frequencies. Nonetheless, it is also known that runaway thermal conditions and excessive heat generated by chips is a leading cause of failure of chip devices. Furthermore, it is anticipated that demand for heat removal from these devices will increase indefinitely. Accordingly, it is seen that there is a large and significant need to provide useful cooling mechanisms for electronic circuit devices. 
   Each new generation of computers continues to offer increased speed and function. In most cases, this has been accomplished by a combination of increased power dissipation and increased packaging density. The net result has been increased heat flux at all levels of packaging. For example, one packaging configuration for certain large computer systems today is a multi-blade server system, with each blade containing one or more processor modules along with associated electronics, such as memory, power and hard drive devices. These blades are removable units so that in the event of failure of an individual blade, the blade may be removed and replaced in the field. One problem with this configuration is that the increase in heat flux at the blade level makes it increasingly difficult to dissipate heat by simple air cooling. 
   Further, in certain data center equipment, a rack containing blade server systems may house several hundred or more microprocessors, which sharply increases the heat dissipation requirements. These systems place an enormous burden on the facility air conditioning system, since all rack or blade server heat is conventionally dissipated into the room ambient air. These air cooled structures are becoming limited in their thermal performance capability by the modest amount of air flow available for cooling. In addition to this restriction, with projected per rack heat loads to exceed 25 kW in the near future, the burden on the facility air conditioning is very high. Thus, an alternative to the state of the art air cooling is desirable. 
   SUMMARY OF THE INVENTION 
   The needs of the prior art are addressed, and additional advantages are provided, by the present invention, which in one aspect is a coolant isolation valve assembly usable with a liquid cooled electronics subsystem which is insertable in an operational position within an electronics housing. The coolant isolation valve assembly includes at least one isolation valve and at least one actuation mechanism. The at least one isolation valve is coupled to at least one of a coolant supply line and a coolant return line providing liquid coolant to the liquid cooled electronics subsystem when operational within the electronics housing. The at least one actuation mechanism is coupled to the at least one isolation valve, and automatically translates a linear motion, resulting from insertion of the liquid cooled electronics subsystem in an operational position within the electronics housing, into a rotational motion to open the at least one isolation valve and allow coolant to pass therethrough. The at least one actuation mechanism operates to automatically close the at least one isolation valve when the liquid cooled electronics subsystem is withdrawn from the operational position within the electronics housing. 
   In another aspect, a coolant connect/disconnect assembly is provided for a liquid cooled electronics subsystem which is insertable in an operational position within an electronics housing. This coolant connect/disconnect assembly includes a compression valve coupling and an isolation valve assembly. The compression valve coupling includes a first fitting and a second fitting. The first fitting is associated with the liquid cooled electronics subsystem and the second fitting is associated with the electronics housing. The first fitting and the second fitting automatically engage to allow coolant flow therethrough when the liquid cooled electronics subsystem is inserted in the operational position within the electronics housing, and automatically disengage to prevent coolant flow when the liquid cooled electronics subsystem is withdrawn from the operational position within the electronics housing. The isolation valve assembly is disposed within the electronics housing serially and in fluid communication with the second fitting of the compression valve coupling. The isolation valve assembly includes an isolation valve disposed in at least one of a coolant supply line and a coolant return line within the electronics housing, and an actuation mechanism. The actuation mechanism automatically translates a linear motion, resulting from insertion of the liquid cooled electronics subassembly in the operational position within the electronics housing, into motion to open the isolation valve and allow coolant flow therethrough. The actuation mechanism operates to automatically close the isolation valve when the liquid cooled electronics subsystem is withdrawn from the operational position within the housing. 
   In a further aspect, a liquid cooled electronics system assembly is provided which includes a plurality of electronics subsystems and an electronics housing. The plurality of electronics subsystems are insertable into the electronics housing in an operational position. The assembly further includes a liquid coolant subsystem for providing liquid coolant to at least one electronics subsystem of the plurality of electronics subsystems. The liquid coolant subsystem includes at least one isolation valve assembly having an isolation valve and an actuation mechanism. The isolation valve is coupled to at least one of a coolant supply line and a coolant return line providing liquid coolant to the at least one electronics subsystem when operational within the electronics housing. The actuation mechanism is coupled to the isolation valve and automatically translates a linear motion, resulting from insertion of the at least one electronics subsystem in the operational position within the electronics housing, into a rotational motion to open the isolation valve and allow coolant flow therethrough. The actuation mechanism operates to automatically close the isolation valve when the at least one electronics subsystem is withdrawn from the operational position within the electronics housing. 
   Methods for fabricating the isolation valve and coolant connect/disconnect assemblies disclosed herein are also described and claimed. 
   Further, additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
       FIG. 1A  depicts one embodiment of a computer blade server system within which a liquid coolant subsystem can be employed, in accordance with an aspect of the present invention; 
       FIG. 1B  depicts a side elevational view of one embodiment of a blade for the blade server system of  FIG. 1A ; 
       FIG. 1C  depicts an end elevational view of one embodiment of a blade server housing for the blade server system of  FIG. 1A , with the multiple blades of the blade server system removed therefrom; 
       FIG. 2  is a cross-sectional side elevational view of a simplified embodiment of a blade and blade server housing employing a compression valve coupling allowing blind connection of coolant flow paths to provide coolant from the blade server housing to one or more cold plates within the blade, in accordance with an aspect of the present invention; 
       FIG. 3  depicts a cross-sectional side elevational view of one embodiment of a blade server housing showing a blade partially removed, wherein multiple coolant connect/disconnect assemblies are shown each including an isolation valve assembly in series with a compression valve coupling, in accordance with an aspect of the present invention; 
       FIG. 4  is a side elevational view of the blade and blade server housing embodiment of  FIG. 3  showing the blade in operational position within the blade server housing, and showing the compression valve fittings engaged and the isolation valve assemblies engaged to allow coolant flow therethrough, in accordance with an aspect of the present invention; 
       FIG. 5  is an isometric view of one embodiment of an isolation valve assembly, in accordance with an aspect of the present invention; 
       FIG. 5A  is an exploded view of the isolation valve assembly of  FIG. 5 , in accordance with an aspect of the present invention; 
       FIG. 6  is a partially assembled isometric view of the isolation valve assembly of  FIGS. 5 &amp; 5A  showing the ball valve gate in a closed position, in accordance with an aspect of the present invention; 
       FIG. 7  is a partially assembled isometric view of the isolation valve assembly of  FIGS. 5 &amp; 5A  showing the ball valve gate in an open position, in accordance with an aspect of the present invention; 
       FIG. 8  is an isometric view of another embodiment of an isolation valve assembly, in accordance with an aspect of the present invention; 
       FIG. 8A  is an exploded view of the isolation valve assembly of  FIG. 8 , in accordance with an aspect of the present invention; 
       FIG. 9  is a partially cut-away isometric view of the isolation valve assembly of  FIGS. 8 &amp; 8A  showing the butterfly valve in a closed position, in accordance with an aspect of the present invention; and 
       FIG. 10  is a partially cut-away isometric view of the isolation valve assembly of  FIGS. 8 &amp; 8A  showing the butterfly valve in an open position, in accordance with an aspect of the present invention. 
   

   BEST MODE FOR CARRYING OUT THE INVENTION 
   As used herein “liquid cooled electronics subsystem” refers to any receptacle, compartment, node, book, drawer, blade, etc., containing one or more heat generating components of a computer system or other electronics system employing liquid cooling. The term “electronics module” includes any heat generating component of a computer system or electronics system, and may be, for example, one or more integrated circuit devices, or one or more packaged electronics devices (such as a processor module). The term “electronics housing” includes any frame, rack, chassis, etc. designed to receive one or more liquid cooled electronics subsystems; and may be, for example, a stand alone computer processor having high, mid or low end processing capabilities. In one embodiment, an electronics housing may comprise one or more blade server system chassis, each having one or more blades requiring cooling. 
   By way of example, various aspects of the present invention are disclosed hereinbelow with reference to a blade server system, one embodiment of which is depicted in  FIGS. 1A-1C . The blade server system  100  of  FIG. 1A  includes an electronics housing or blade server chassis  110  and multiple blades  120  (each comprising one example of an electronics subsystem) which insert into the blade server chassis when in operational position. 
     FIG. 1B  depicts one simplified embodiment of a blade  120 . This electronics subsystem includes multiple processors upon which reside respective air cooled heat sinks  122 . In this example, each blade is a complete computer system, and includes, for example, DASD  124  and memory chips  126 . Electrical connectors  128  are provided for electrically connecting blade  120  to the blade server chassis  110  ( FIG. 1C ). As shown in  FIG. 1C , corresponding electrical connectors  130  are disposed within the blade server chassis for making electrical connection to connectors  128  when the blade is inserted therein in an operational position. 
   As noted, advances in semiconductor technology have led to exponential increases in microprocessor performance. This has resulted in steep increases in the amount of cooling required to ensure package operation and reliability. In data center equipment, such as racks containing multiple blade server systems, hundreds or even thousands of microprocessors may be placed in close proximity, resulting in significant heat dissipation requirements. 
     FIG. 1B  depicts the conventional use of air cooled heat sinks for the blades of the blade server system. These air cooled heat sinks might include a vapor chamber base to spread heat from the chip package and transfer it, via fins, to the ambient air. Unfortunately, these air cooled structures are limited in their thermal performance capability by the relatively modest amount of air flow available for cooling. In addition, with projected rack heating loads to exceed 25 kW in the near future, the burden on facility air conditioning continues to grow, particularly when a facility contains a large number of blade server systems. Thus, as an alternative, liquid coolant based solutions are believed to be advantageous. Unfortunately, liquid based solutions are accompanied by reliability concerns, and must be designed to be leak-proof. In addition, the customer would require the option of inserting and removing a blade in the field while the system is in operation. Thus, the cooling system also needs to be modular. In addition to the benefits noted, liquid cooling can further reduce device temperature, thus enhancing processor performance. 
   One technique for providing a modular, liquid cooled electronics subsystem is described in commonly assigned, co-pending U.S. patent application Ser. No. 10/675,628, filed Sep. 30, 2003, entitled “Thermal Dissipation Assembly and Fabrication Method for Electronics Drawer of a Multiple-Drawer Electronics Rack,” the entirety of which is hereby incorporated herein by reference. Presented herein below are several alternative coolant subsystem embodiments for a liquid cooled electronics subsystem, which are both modular and highly reliable. The concepts presented are applicable to any type of packaging structure wherein one level of packaging is inserted into a higher level of packaging and where heat dissipation requirements are significant. 
     FIG. 2  depicts one embodiment of a blade server system  200  having a blade chassis or housing  210  and one or more blades  220  inserted therein. Each blade includes one or more processors  221  over which a respective cold plate  222  is disposed. Cooling liquid flows through appropriate tubing  224  within the blade, and is provided from a facility coolant source passing through manifolds  240  and  250  associated with the electronics housing  210 . Self-sealing compression valve couplings  230  include a first fitting  232  and a second fitting  234  between the blade  220  and the housing  210  portions of the coolant supply lines. This allows blade  220  to be removed and returned to the electronics housing without any impact on the liquid cooling circuit. A supply manifold  240  receives liquid coolant from a supply line(s)  241  and provides liquid coolant to the coolant tubing  224  within the respective blade via an inlet coolant line  242 . Similarly, an outlet manifold  250  receives system coolant from the coolant tubing of blade  220  via a respective coolant outlet line(s)  252  and discharges the heated coolant from manifold  250  via a return line  251 . 
   The first fitting and second fitting of the compression valve coupling are a blind connect/disconnect coupling which automatically establishes a fluid connection when blade  220  is inserted into an operational position within the electronics housing, and which automatically disengage when the blade is removed from the operational position. By way of example, non-latching, automatic self-sealing couplings are available in the art from Parker Hannifin Corporation of Fort Worth, Tex. Other automatic self-sealing couplings appropriate for use in accordance with the present invention are also commercially available. Preferably, the self-sealing coupling opens and seals automatically as the liquid cooled electronics subsystem is inserted into and is removed from the operational position within the electronics housing. Because of the catastrophic nature of a failure of the second fitting, it is desirable to provide a further guarantee that liquid coolant can not discharge into the housing with withdrawal of an electronics subsystem. This might occur, for example, should a poppet within the second fitting of the compression valve stick, resulting in coolant being discharged into the blade server housing. 
     FIG. 3  depicts a further embodiment of the present invention wherein a coolant connect/disconnect assembly  300  is employed within the blade server housing  210  on both the coolant supply line and the coolant return line. Each connect/disconnect assembly  300  includes an isolation valve assembly and, for example, the compression valve coupling  230  of  FIG. 2 . The second fitting  234  of the compression valve coupling again couples to the first fitting  232  associated with the respective removable blade  220  as the blade is brought into or docked in an operable position within the housing. 
   The isolation valve assembly  310  provides an additional level of coolant isolation protection for the system. In the event of failure of the quick connect coupling, the isolation valve assembly also ensures that coolant will not spray under pressure onto the electronics subsystems. Isolation valve assembly  310  includes an isolation valve disposed within a valve housing  312  and an actuation mechanism  314  coupled to the isolation valve. Actuation mechanism  314  includes a linearly translatable interface member  316 , and converts linear movement of member  316  to, for example, rotational movement of the isolation valve. In the embodiment shown in  FIG. 3 , blade  220  is partially removed from the electronics housing  210  and thus the interface member  316  is shown extended, and the associated isolation valve is closed (see  FIG. 6 ). The second fitting of the compression valve coupling and the isolation valve of the isolation valve assembly are shown in fluid communication and are disposed in series to ensure closing of, e.g., the coolant inlet line and coolant outlet line upon withdrawal of the associated blade from the blade server chassis. The isolation valve assembly could, if desired, also be employed within the individual blades of the blade server system. However, the isolation valve assembly is particularly beneficial on the high pressure side of the compression valve couplings, that is, the blade server chassis side of the coupling. The first fitting  232  in the respective blade is less likely to cause damage since there is less force on that coolant coupling when the blade is removed. 
     FIG. 4  depicts the assembly of  FIG. 3  with blade  220  shown in an operational position within blade server chassis  210 , and first fitting  232  and second fitting  234  engaged to allow coolant to pass therethrough. In addition, each interface member  316  is translated, resulting in actuation mechanism  314  rotating the respective isolation valve in each isolation valve housing  312  to an open position. 
   One embodiment of an isolation valve assembly  310 , in accordance with an aspect of the present invention, is depicted in  FIGS. 5-7 . In this embodiment, the valve assembly  310  includes a ball valve housing  312  and an actuation mechanism  314  having a linearly reciprocating interface member  316 . The ball valve housing  312  is disposed, for example, in series within the inlet line  242  with second compression valve socket  234 . This isolation valve assembly provides enhanced shut off actuation upon withdrawal of a blade from the blade server housing. The isolation valve assembly would be mechanically coupled to the blade server housing, while the blade need only have a rigid member aligned to the interface member  316  to present a solid surface to contact the interface member when the blade is inserted into the operational position within the blade server housing. Isolation valve assembly  310  provides a reliable shut off of coolant flow when the blade connection is broken, and a reliable turn on of coolant flow when the blade is reconnected in an operational position. 
     FIG. 5A  depicts a more detailed embodiment of the isolation valve assembly of  FIG. 5 . The actuation mechanism  314  includes a rack  500  and pinion gear  510 . One end of rack  500  comprises the interface member  316 . Rack  500  reciprocates linearly via guide pins  524  and appropriately provided guide pin grooves within the rack. One or more rack return springs  512  are employed to ensure automatic closing of the ball valve gate when the blade is removed from the operational position. The rack and pinion reside between a support block  520  and a cover plate  522 . The cover plate, support block, and ball valve housing are, in one embodiment, fastened together rigidly, and the resultant assembly is rigidly fastened to, for example, the blade server chassis. The rack&#39;s motion is restrained by the cover plate, guide block, and guide pins. 
   A shaft  530  connects pinion gear  510  to a ball valve gate  540  (in one embodiment). Gate  540 , which resides within a lower ball valve housing  550  and an upper ball valve housing  560 , rotates 90° between a closed position and an open position, depending upon whether rack  500  is extended by springs  512  or translated by the associated blade (not shown). The ball valve gate is shown to be in series and in fluid communication with the second fitting or socket  234  of a corresponding compression valve coupling as depicted in  FIGS. 3 &amp; 4 . In operation, the rack moves laterally when contacted by a respective electronics subsystem, while the rack teeth engage the pinion gear, which rotates the ball valve gate with respect to the ball valve housing by means of the common shaft. 
     FIG. 6  depicts the isolation valve assembly of  FIGS. 5 &amp; 5A  with the rack return springs  512  relaxed, the rack  500  extended, and the ball valve gate  540  in a closed position relative to the ball valve housing, i.e., the axis of the center hole in the ball valve gate is rotated perpendicular to the axis of fluid passage in the ball valve housing, thus preventing fluid flow. Cover plate  522  and upper ball valve housing  560  are shown in phantom and exploded view for clarity. The isolation valve assembly depiction of  FIG. 6  assumes that the associated blade has been disengaged from the interface member end of rack  500 , and is in a non-operational position. In the event of failure of fitting  234 , the isolation valve assembly ensures that coolant can not spray under pressure onto the electronics of the blade or the electronics of the blade server chassis. The ball valve body should be coupled to the blade server coolant supply by means of a hose, tube, pipe, etc. As used herein, “facility coolant” or “blade server coolant supply” refers to data center coolant provided through the blade server chassis, and which by way of example, may refer to cooled (and possibly conditioned) water or other coolant. 
     FIG. 7  again shows the assembled isolation valve assembly of  FIGS. 5 &amp; 5A  with cover plate  522  and upper ball valve housing  560  exploded and shown in phantom. In this example, rack return springs  512  are compressed by rack  500 , which is assumed to be engaging a blade in operational position within the blade server housing. The compressed rack return springs  512  provide the force to return the rack to the extended position and close the valve when the blade is removed. When the rack is compressed as shown, the ball valve gate  540  is in an open position, with the axis of the center opening in the ball valve gate coincident with the axis of the fluid passage in the ball valve body. 
     FIG. 8  depicts an alternate embodiment of an isolation valve assembly, generally denoted  800 , in accordance with an aspect of the present invention. Assembly  800  can be used in place of assembly  310  of  FIGS. 5-7 . In this example, the interface member  810  is assumed to be mechanically connected to or integrated with the blade (not shown). Assembly  800  includes an isolation valve disposed within a housing  830  and an actuation mechanism  820  for translating linear reciprocal motion of interface member  810  to a rotational motion for opening and closing the isolation valve within isolation valve housing  830 . The isolation valve is again shown in series and in fluid communication with a second fitting portion  234  of a blind quick connect/disconnect coupling. 
     FIG. 8A  depicts an exploded view of the isolation valve assembly of  FIG. 8 . As shown, the actuation mechanism includes a structural housing  826  within which is disposed a cam  822  and a cam/valve return spring  824 . A cover  828  seals housing  826  except for an appropriately sized opening aligned to receive the reciprocating interface member  810  attached to the associated blade. In this example, cam  822  is mechanically connected via a shaft  842  to a butterfly valve  840 . Butterfly valve  840  resides within a lower valve housing  850  and an upper valve housing  860  and is in series and in fluid communication with the second fitting  234  of the blind connect/disconnect coupling. 
   In  FIG. 9 , the assembled isolation valve assembly  800  is partially broken away to show cam  822  in a neutral position with the cam spring  824  relaxed and the butterfly valve  840  in closed position blocking any coolant flow. In  FIG. 10 , the interface member  810  is shown engaging cam  822  applying a force to spring  824  resulting in torsional stress on the spring and opening butterfly valve  840 . The torsional stress of spring  824  ensures return of cam  822  to the neutral position when the interface member  810  is removed withdrawal of the blade from an operational position within the blade server chassis. 
   Those skilled in the art will note from the above discussion that provided herein are an isolation valve assembly, a coolant connect/disconnect assembly, a liquid cooled electronics system assembly, and methods of fabrication thereof, which advantageously allow repeated automatic shut-off and opening of isolation valves associated with a liquid coolant subsystem employed to cool one or more heat generating components of an electronics subsystem which is operable when inserted into an electronics housing. The isolation valve assembly is reusable even after failure of an associated compression valve coupling. Automatic valve shut-off and automatic valve opening are provided via an actuation mechanism which translates a linear movement of the electronics subassembly within the electronics housing to a rotational movement of the isolation valve. Reliable module level and rack level liquid cooling of a plurality of electronics subsystems is facilitated for various electronics systems, such as a single computer or larger computing and data processing equipment. Further, the concepts presented can be employed to design valve shut-off to occur momentarily prior to de-coupling, as well as valve opening to occur momentarily after coupling of the electronics subsystem in an operational position within the electronics housing. This ensures significantly lower pressure on the compression valve coupling fittings at the time of de-coupling and at the time of coupling of the electronics subsystem to the liquid coolant subsystem. The mechanical actuation member of the isolation valve assembly can be separate from the compression valve coupling, and may be positioned within the electronics housing or within the electronics subsystem. A result of this is that the mechanical structure incorporating the compression valve coupling does not need to be located at the point of valve actuation. 
   Although preferred embodiments have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the following claims.