Patent Publication Number: US-2021190218-A1

Title: Pressure regulator valve assembly for quick disconnect fittings

Description:
BACKGROUND 
     Couplings used in cooling systems or other applications may facilitate repair, upgrading, servicing, and/or replacement of components with minimal downtime. Liquid cooling systems may use various couplings depending on, among other things, the type of cooling system and the working fluid(s) used therein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a rack that includes a liquid cooling system and utilizes quick disconnect fittings that include pressure-regulating valve assemblies in accordance with embodiments of the present disclosure. 
         FIGS. 2A-C  are various views of a pressure regulator valve assembly in accordance with embodiments of the present disclosure. 
         FIG. 3  is a schematic diagram of an example quick disconnect plug that includes a pressure regulator valve assembly in accordance with embodiments of the present disclosure. 
         FIG. 4  is a schematic diagram of a quick disconnect plug with a pressure regulating valve assembly coupled to a quick disconnect socket  400  in accordance with embodiments of the present disclosure. 
         FIG. 5  is a schematic diagram of a quick disconnect fitting plug coupled to a quick disconnect socket and a pressure regulator valve assembly in the plug under pressure in accordance with embodiments of the present disclosure. 
         FIG. 6  is a schematic diagram of an example pressure regulator valve in accordance with embodiments of the present disclosure. 
         FIG. 7  is a schematic diagram of a quick disconnect fitting comprising a pressure regulator valve assembly  600  in accordance with embodiments of the present disclosure. 
         FIG. 8  is a schematic diagram of a quick disconnect fitting plug and socket coupled together and a pressure regulator valve under pressure in accordance with embodiments of the present disclosure. 
         FIG. 9  is a schematic diagram of an example socket stem that includes a high-pressure relief surface in accordance with embodiments of the present disclosure. 
     
    
    
     Figures are not drawn to scale. 
     DETAILED DESCRIPTION 
     This disclosure describes a pressure regulator valve assembly (or pressure regulating valve assembly) for use in quick disconnect fittings used in the liquid cooling of computing system components, such as processor units in rack computing solutions (e.g., blades, trays, sleds). Liquid cooling is a highly effective way to increase the performance of processor units and other computing system components (e.g., memory, storage), in part because of the increased thermal cooling capability provided by a liquid-cooled system versus an air-only cooling system. Quick disconnect (or quick connect, quick release, etc.) couplings or fittings are used to connect a fluid manifold supported by a rack to the cooling loops of the computing systems (e.g., servers) also supported by the rack. Each manifold may have many fluid loops connected to it. Each of these fluid loops has its own flow resistance, which may be significantly different from other fluid loops in the same manifold. This difference in flow resistance can cause maldistribution of fluid in the loops and may require unnecessary pump power to ensure the loops receive appropriate flow rates. 
     This disclosure describes a pressure-regulating valve with a quick disconnect coupling to reduce system-level pressure variations. The pressure-regulating valve can be integrated into a quick disconnect coupling at low cost. Other advantages are readily apparent to those of skill in the art. Among the various advantages include the low cost of integration of precision nozzle outlets in quick disconnect fitting valve assemblies, lower overall cost of cold plate-based liquid cooling solutions, reduced number of components to implement pressure regulation of fluids entering computing systems, and increased reliability of rack-level liquid cooling solutions. In embodiments, the pressure-regulating valve allows the tuning of individual loops to optimize fluid distribution. 
     Additional advantages include facilitating a simple, low-cost method to reduce facility line or information technology (IT) secondary fluid line pressure to acceptable levels for cooling distribution units (CDUs) or heat exchangers (HXs) or cold plates and assemblies. The pressure regulating valve assemblies and quick disconnect fittings utilizing these valve assemblies disclosed herein can reduce the number of components required to enable and procure a liquid-cooled system. The pressure-regulating valve assembly and quick disconnect fitting design metrics and parameters can be chosen based on existing quick disconnect designs. 
     The quick disconnect fitting and pressure-regulating valve assemblies can be chosen based on the pressure rating needed for that system and can be replaced to handle a different pressure rating in the field as needed. No matter which CDU or facility IT loop is connected, the pressure-regulating valve assemblies can maintain desired fluid pressures linking to the system (e.g., CDU or rack computing systems). 
     One can theoretically measure the liquid volumetric flow rate through each computing system in a rack by simple pressure drop taps due to the use of the nozzle outlet and valve channel. Currently, if one needs to measure flow rate through each computing system, costly in-line flow meters may need to be used. Selling computing systems with liquid cooling utilizing the quick disconnect fittings disclosed herein can help original design manufacturers (ODMS) and original equipment manufacturers (OEMs) in that liquid cooling solutions will meet safety requirements regardless of the type of computing system the quick disconnect fittings are connected to. 
     In this disclosure, the terms “valve” and “valve assembly” refer to devices that control the flow of fluid through a fluid channel. Controlling the flow of fluid can include pressure balancing the fluid in case of a pressure imbalance on either side of the valve or valve assembly. In embodiments, the term “poppet” is used to describe the valve assembly&#39;s general shape. 
       FIG. 1  is a schematic diagram  100  of a rack  102  that includes a liquid cooling system and utilizes quick disconnect fittings that include pressure-regulating valve assemblies in accordance with embodiments of the present disclosure. Rack  102  can mechanically support one or more computing systems  104  (e.g., server computing systems). Each computing system  104  can comprise a case that houses one or more computing system components, such as one or more processor units, memory, routing hardware, storage, fans, peripherals, switches, interconnects, add-in cards, etc. A computing system  104  can include a liquid cooling system to provide cooling to one or more computing system components housed within a case. A computing system  104  can include a liquid supply quick disconnect coupling  112  and a liquid return quick disconnect coupling  114 . The supply and return quick disconnect couplings  112  and  144  for one computing system  104  can connect to one or more conduits that form a loop to route incoming cooling liquid to one or more cold plates attached to one or more computing system components for cooling the computing system components and to route the heated liquid out of the computing system  104  through the return quick disconnect coupling. 
     As used herein, the terms “processor unit” and “processing unit” can refer to any processor, processor core, component, module, engine, circuitry, or any other processing element described or referenced herein. A processor unit can take various forms such as a central processing unit (CPU), a graphics processing unit (GPU), general-purpose GPU (GPGPU), accelerated processing unit (APU), field-programmable gate array (FPGA), neural network processing unit (NPU), data processor unit (DPU), accelerator (e.g., graphics accelerator, digital signal processor (DSP), compression accelerator, artificial intelligence (AI) accelerator), controller, or other types of processing units. As such, the processor unit can be referred to as an XPU (or xPU). Further, a processor unit can comprise one or more of these various types of processing units. In some embodiments, the computing system comprises one processor unit with multiple cores, and in other embodiments, the computing system comprises a single processor unit with a single core. 
     In some embodiments, the rack  102  is located in a data center, such as an enterprise data center (e.g., a data center owned and operated by a company and typically located on company premises), managed services data center (e.g., a data center managed by a third party on behalf of a company), a colocated data center (e.g., a data center in which data center infrastructure is provided by the data center host and a company provides and manages their own data center components (servers, etc.)), cloud data center (e.g., a data center operated by a cloud services provider that host companies applications and data), and an edge data center (e.g., a data center, typically having a smaller footprint than other data center types, located close to the geographic area that it serves). 
     The rack  102  can support a liquid cooling system for the computing systems  104 . The liquid cooling system can include a cooling distribution unit (CDU)  106 . CDU  106  can include a liquid supply line  108  and a liquid return line  118 . A supply manifold  110  delivers cooling liquid from CDU  106  to computing systems  104  in the rack  102  and a return manifold  116  delivers heated cooling liquid from computing systems  104  to the CDU  106 . 
     Liquid-cooled systems require a cooling IT loop or facility water connection (supply line) to connect to the respective cold plates inside computing systems  104 , Cooling Distribution Units (CDUs)  106 , or Heat Exchangers (HXs) present in the system. The liquid (e.g., water) supply line  108  in a typical water-cooled data center is maintained at a high-pressure level capable of overcoming the pressure drop of the system and maintaining the required flow rate for system cooling requirements. In order to safely provide fluid to individual cold plates inside rack computing systems, CDUs, or HXs, the fluid pressure is reduced via a pressure-regulating valve prior to entering the CDU or HX. As per the International Electrotechnical Commission (IEC) standard, any liquid-cooled systems must not leak under 5× operating pressure. 
     This disclosure describes pressure regulating valve assemblies that have a “poppet” architecture for use in quick disconnect fittings in liquid cooling solutions. The valve assemblies are used in a quick disconnect plug of a quick disconnect fitting and incorporate a pintle and a valve nozzle. The valve nozzle comprises a nozzle outlet and the valve nozzle and pintle define a valve channel for the valve assembly. The volume of the valve channel and the size of the nozzle outlet can be determined to control or reduce the pressure through a quick disconnect fitting based on operational parameters of a liquid cooling system or other factors. The quick disconnect plug connects to a quick disconnect socket to form a quick disconnect fitting. In a disconnected stage, the pressure regulating valve assembly prevents drips by seating the valve assembly in a fluid inlet of a quick disconnect plug. 
     In some embodiments, in an engaged state, the valve assembly rests against a plug spring. The nozzle outlet of the valve assembly is maintained at a desired opening volume through which fluid can pass. When there is a short burst of pressure increase, such as can occur immediately after a quick disconnect plug is connected to a quick disconnect socket, the valve assembly is pushed against the plug spring, which can reduce the volume of the valve channel volume while maintaining a desired fluid pressure downstream of the valve assembly. After the incoming high fluid pressure transient has passed, the plug spring pushes the valve assembly back to its seated position against the quick disconnect socket and the valve assembly continues to regulate fluid pressure at original valve flow coefficient (Cv) values. As the volume of the valve channel volume is spring-based, the fluid pressure regulation is automatic, passive, and quick, allowing cold plate and computing system-level liquid cooling components to be designed for quick disconnect fittings utilizes the pressure-regulating valve assemblies disclosed herein for various applications. This can help reduce the cost and weight of computing systems while still meeting International Electrotechnical Commission (IEC)/Underwriters Laboratories Inc. (UL) safety guidelines. 
     In some embodiments, the valve assembly can include a pressure regulating spring (or pintle spring) between the pintle and the nozzle. The pintle spring can compress under high-pressure conditions to restrict flow through the nozzle outlet. The poppet can include a pressure relief channel. When the poppet is unseated under high-pressure conditions, the pressure relief channel is exposed and permits fluid flow at controlled rates. 
     The aforementioned embodiments, among others, are described in more detail below. 
       FIGS. 2A-C  are various views of a pressure regulator valve assembly  200  in accordance with embodiments of the present disclosure.  FIG. 2A  is a side view of a pressure regulator valve assembly  200 .  FIG. 2B  is a cross-sectional view of the pressure regulator valve assembly  200 .  FIG. 2C  is an isometric view of the pressure regulator valve assembly  200 . Pressure regulator valve assembly  200  (or simply, valve assembly  200 ) can include a pintle  202  and a valve nozzle  204 . The pintle  202  (also referred to as a pressure dampening pintle) can extend from a body  212 . Body  212  can be substantially cylindrical and sized to fit into a fluid inlet and fluid channel of a quick disconnect plug. The body  212  can include a recess  214  to accommodate an O-ring. The O-ring (shown later) can prevent drips from the plug while the plug is disconnected from a quick disconnect socket. 
     The pintle  202  can have different shapes and aspect ratios. In embodiments, the pintle  202  can be mushroom-shaped, conical, tapered, tapered spherical, semi-spherical, etc. The size and shape of the pintle  202  can be selected based on operating pressures of a liquid cooling system. The pintle  202  and the valve nozzle  204  can cooperate to create a valve channel  208  that extends through the valve nozzle  204  and a nozzle outlet  206 . The valve channel  208  can have a volume that is determined based on the operational and pressure requirements of the liquid cooling system. The valve channel is shown specifically in the cross-sectional view in  FIG. 2B . 
     The pintle  202  can be coupled to the valve nozzle by a connective member  210 . Connective member  210  can be flexible so that pintle  202  can move inwards towards the valve nozzle  204  to reduce the opening of the valve channel  208  and restrict fluid flow in a high-pressure situation. In some embodiments, a pintle spring can be used instead of a connective member  210 . Other structures can also be used to achieve similar results. 
     In some embodiments, the valve nozzle  204  includes a recess  216  to accommodate an O-ring. 
       FIG. 3  is a schematic diagram of an example quick disconnect plug  300  that includes a pressure regulator valve assembly  200  in accordance with embodiments of the present disclosure. The quick disconnect plug  300  can carry liquid to cool one or more processor units and/or other components of a computing system. The quick disconnect plug  300  includes a plug body  302  that can be received into a quick disconnect socket and secured into the socket without leaking. Together, the quick disconnect plug  300  and a corresponding quick disconnect socket comprises a quick disconnect fitting. The plug body  302  includes a fluid inlet  304 . Fluid inlet  304  allows fluid to flow from the quick disconnect socket into a fluid channel  306  in the plug body  302 . Plug body  302  can include features that allow for quick connection and disconnection of the quick disconnect plug  300  from a quick disconnect socket. A pressure regulator valve assembly  200  resides within the fluid channel  306 . 
       FIG. 3  shows a pressure regulator valve assembly  200  in a position within the fluid channel  306  when the plug  300  is not coupled to a socket. It is understood that when the plug  300  is not connected to a socket, the pressure regulator valve assembly  200  is positioned proximate the fluid inlet  304  of the plug to prevent leakage. O-ring  310  seals the fluid inlet  304 . In the disconnected state, the valve assembly O-ring  310  prevents drips by seating the valve assembly  200  in the fluid inlet  304  of the plug  300 . In embodiments, O-ring  312  also prevents drips by sealing against a wall of the fluid channel  306 .  FIGS. 4 and 5  illustrate the plug  300  connected to a socket. 
       FIG. 4  is a schematic diagram of a quick disconnect plug with a pressure regulating valve assembly coupled to a quick disconnect socket  400  in accordance with embodiments of the present disclosure. The socket  400  includes a socket body  402 . Socket body  402  can include a receptacle to receive the plug  300  to allow the passage of fluid from the socket through the plug without leaks at or up to a predetermined pressure. The socket  400  also includes quick connect and/or quick disconnect features. 
     Within the socket body  402  is a socket spring  408  and a plunger  406 . A portion of the plug body  302  can push on the plunger  406  which is resisted by the socket spring  408  to cause a plug face  320  to be seated against a socket face  420 . The arrows represent fluid flow direction. 
     The socket  400  includes a socket stem  404 . When the plug  300  is connected to socket  400 , the socket stem  404  pushes the pressure regulator valve assembly  200  into the fluid channel  306  and against the plug spring  308 . The socket stem  404  is rigidly affixed within the socket body  402 .  FIG. 4  illustrates a no pressure or relatively low-pressure example. Under no pressure or relatively low-pressure conditions (or operational conditions within an ideal tolerance), the pressure regulator valve assembly  200  is seated against the socket stem  404 . 
       FIG. 5  is a schematic diagram of a quick disconnect fitting plug coupled to a quick disconnect socket and a pressure regulator valve assembly in the plug under pressure in accordance with embodiments of the present disclosure. As can be seen in  FIG. 5 , when fluid is flowing through the quick disconnect fitting from the socket to the plug at high pressure, the pressure regulator valve assembly  200  is pushed away from the socket stem  404 . The fluid pressure pushes the pressure regulator valve assembly  200  further against plug spring  308 , which increases a volume of the fluid channel  306  between the pressure regulator valve assembly  200  and the socket stem  404 . The liquid flow can be controlled by a change in the volume of the valve channel  208  volume due to the pintle  202  being pushed towards the valve nozzle  204  by the high-pressure liquid due to a flexible connective member connecting the pintle  202  to the valve nozzle  204  or a pintle spring located between the pintle  202  and the valve nozzle  204 . When the high-pressure subsides, the plug spring  308  pushes the valve assembly  200  back to the seated position against the socket stem  404  (as shown in  FIG. 4 ). 
     O-ring  312  is shown in  FIGS. 3-5 . O-ring  312  prevents fluid from flowing around the valve assembly  200  and helps to direct fluid into the valve channel  208 . 
       FIG. 6  is a schematic diagram of an example pressure regulator valve assembly  600  in accordance with embodiments of the present disclosure. Pressure regulator valve assembly  600  is similar to that shown in  FIGS. 2A-C . Pressure regulator valve assembly  600  includes a pintle  602  and a valve nozzle  604 . Valve nozzle  604  includes an outlet  606  through which fluid flowing through a valve channel  608  exits the valve nozzle  604 . 
     The pintle  602  is shown to be a slightly different shape and aspect ratio than shown in  FIGS. 2A-C . As mentioned previously, the pintle shape and size of a pressure regulating valve assembly can be selected based on operational parameters. 
     The valve assembly  600  includes a pintle spring  610 . Pintle spring  610  can couple the pintle  602  with the valve nozzle  604 . Pintle spring  610  can compress when the pintle experiences high fluid pressure causing the valve assembly  600  to become unseated and the volume of the valve channel  608  to decrease. In some embodiments, the pintle  602  includes a low-pressure fluid bypass channel  612  that extends from a surface of the pintle  602  to the valve channel  608  (shown in  FIGS. 7 and 8 ). 
       FIG. 7  is a schematic diagram of a quick disconnect fitting  700  comprising a pressure regulator valve assembly  600  in accordance with embodiments of the present disclosure.  FIG. 7  illustrates a no- or low-pressure situation. The quick disconnect fitting  700  includes a plug  702  connected to a socket  712 . The plug  702  is similar to plug  300 . Socket  712  is similar to socket  400 . 
     Plug  702  includes a plug body  703  that can be received into a quick disconnect socket  712  and secured into the socket  712  without leaking. The plug  702  includes a fluid inlet  704 . Fluid inlet  704  allows fluid to flow from the socket  712  into a fluid channel  706 . Plug  702  can include features that allow for quick connection and disconnection of the plug  702  from socket  712 . 
     Plug  702  includes a valve assembly  600  (shown with low-pressure fluid bypass channel  612 ). Valve assembly  600  is shown to reside in fluid channel  706  (against plug spring  708  when the plug  702  is connected to the socket  712 ). 
     The socket  712  can include a receptacle for receiving the plug  300  to allow the passage of fluid from the socket through the plug without leaks at or up-to a predetermined pressure. The socket  712  also includes the features for quick connect and/or disconnect. 
     Within the socket  712  is a socket spring  718  and a plunger  716 . A portion of the plug  702  can push on the plunger  716 , which is resisted by the socket spring  718  to seat the plug  702  against the socket  712 . 
     The socket  712  includes a socket stem  714 . When the plug  702  is connected to socket  712 , the socket stem  714  pushes the pressure regulator valve assembly  600  into the fluid channel  706  and against the plug spring  708 . The socket stem  714  is rigidly affixed within the socket  712 .  FIG. 7  illustrates a no pressure or relatively low-pressure example. Under no pressure or relatively low-pressure conditions (or operational conditions within an ideal tolerance), the pressure regulator valve assembly  600  is seated against the socket stem  714 . As pressure fluctuates at the system level, the size of the valve assembly fluid outlet remains constant and increased fluid pressure causes the valve assembly  600  to be displaced laterally within the plug fluid channel within the quick disconnect fitting  700 . That is, the valve assembly  600  can slide within the fluid channel in response to varying fluid pressure conditions upstream from the valve assembly. 
     The valve assembly  600  can include a holder  614 . Holder  614  can house the pintle  602 . The pintle  602  can include a low-pressure fluid bypass channel  612  that extends from a surface of the pintle to the valve channel  608 . When seated, the pintle  602  seats against the holder  614  and the socket stem  714 , which seals the low-pressure fluid bypass channel  612 . 
     The holder  614  can also include a recess to accommodate the O-ring (e.g., O-ring  710  in  FIG. 7 ). The O-ring  710  can create a seal in fluid inlet  704  of plug  702 . 
       FIG. 8  is a schematic diagram of a quick disconnect fitting  700  and a pressure regulator valve assembly  600  under high fluid pressure in accordance with embodiments of the present disclosure. As can be seen by  FIG. 8 , under high pressure, the valve assembly  600  unseats from the socket stem  714 . The fluid pressure pushes the pressure regulator valve assembly  600  against plug spring  708 , which increases a volume of the fluid channel  706  between the pressure regulator valve assembly  600  and the socket stem  714 . Volumes  802  and  804  in  FIG. 8  represent portions of the plug&#39;s fluid channel exposed under high-pressure conditions. The valve channel  608  in the valve nozzle  604  is shown to be reduced. The liquid flow can be controlled by the change in the valve channel  608  volume due to the pintle  602  being pushed towards the valve nozzle  604  by the high-pressure liquid. When the high pressure subsides, the plug spring  708  pushes the valve assembly  600  back to the seated position against the socket stem  714  (as shown in  FIG. 7 ). 
     Referring back to  FIG. 7 , under high-pressure conditions, a pressure drop occurs between P 1 , the fluid pressure upstream of the valve assembly, and P 2 , the fluid pressure downstream from the valve assembly, with P 1  being greater than P 2 . If P 1  is much greater than P 2  (e.g., a water hammer event occurs), then the pressure will push the pintle  602  and the pintle spring  610  will compress. The repositioning of the pintle  602  closer to the valve nozzle  604  reduces the valve channel volume and reduces fluid flow. The spring force of pintle spring  610  can be chosen based on the pressure balancing requirements and operational parameters of the liquid cooling system. 
     When the pintle  602  unseats from up against the socket stem  714 , the low-pressure fluid bypass channel  612  will be exposed to the lower pressure P 2  at position  804  in  FIG. 8 . When the pressures P 1  and P 2  are balanced, the plug spring  708  will then force the pintle  602  back into the seated position up against the plunger  716 . Plug spring  708  can include a spring force that is chosen based on the flow requirements, pressure balancing requirements, and/or other operational concerns for the liquid cooling system. 
       FIG. 9  is a schematic diagram of an example socket stem  714  that includes a high-pressure relief surface in accordance with embodiments of the present disclosure. Socket stem  714  can include a seating surface  902  that can interact with valve assembly  200  or valve assembly  600 . The seating surface  902  can contact the valve assembly and push the valve assembly into the fluid channel when the plug is connected to the socket. In no- or low-pressure conditions, the valve assembly is seated against seating surface  902 . 
     The seating surface  902  can include a high-pressure relief surface  904 . The high-pressure relief surface  904  can be milled or cut into the seating surface  902 . The high-pressure relief surface  904  can allow high-pressure liquid to contact the pintle  602  or  202  and unseat the pintle  602  or  202  from the seated position. 
     In some embodiments, a quick disconnect plug can comprise plug sensors that generate plug sensor data that can be monitored to determine plug performance. For example, a force sensor can be used to monitor the amount of compression of a plug spring. In another example, one or more position sensors (e.g., Hall sensor, proximity sensor) can be used to detect a position of a valve assembly within the plug body. If monitored plug sensor data meets a criterion, an alert can be generated. For example, an alert can be generated if force sensor data generated by a force sensor exceeds a spring compression threshold value indicating that the spring has compressed by more than a threshold amount. In another example, an alert can be generated if position sensor data generated by a position sensor indicates that the valve assembly has been pushed past a certain point in the plug body by liquid flowing into the plug. Such alerts can indicate the presence of a high-pressure event in the plug (e.g., a water hammer event). The monitoring of plug sensor data can be performed by the computing system. The alert can be provided to the operating system of the computing system to which the plug is attached and/or a remote orchestrator (e.g., network function virtualization orchestrator (NFVO)). For example, in response to an alert, the computing system could shut itself down or the orchestrator could take one or more of various actions, such as causing the computing system to shut down, causing a CDU to which the computing system is attached to shut down, cause the CDU to reduce the amount of liquid flowing to the computing system, and moving jobs executing on the computing system to another computing system in the same rack or a different rack. 
     In general, this disclosure pertains to a pressure regulating valve assembly and the placement of the valve assembly in quick disconnect fitting plugs. The valve assembly has a valve channel whose volume can change dynamically based on fluid pressure conditions within the quick disconnect fitting. 
     The following pertains to further examples. 
     Example 1 is a quick disconnect plug comprising: a fluid channel; a fluid inlet; and a valve assembly comprising: a pintle; and a valve nozzle comprising an outlet, the pintle and valve nozzle defining a valve channel, the valve channel having a volume that can decrease in response to high-pressure fluid entering the fluid inlet; the valve assembly residing within the fluid channel, the quick disconnect plug to carry liquid to cool one or more processor units of a computing system. 
     Example 2 comprises the quick disconnect plug of Example 1, further comprising a plug spring within the fluid channel, the valve assembly residing between the plug spring and the fluid inlet. 
     Example 3 comprises the quick disconnect plug of Example 2, the valve assembly to slidably move toward the plug spring in response to high-pressure fluid entering the fluid inlet. 
     Example 4 comprises the quick disconnect plug of Example 1, wherein the valve assembly comprises a pintle spring between the pintle and the valve nozzle. 
     Example 5 comprises the quick disconnect plug of Example 1, wherein the pintle comprises a low-pressure fluid bypass channel. 
     Example 6 comprises the quick disconnect plug of Example 1, wherein the pintle is coupled to the valve nozzle by a flexible member. 
     Example 7 comprises the quick disconnect plug of Example 1, further comprising an O-ring surrounding a portion of the pintle or a portion of the valve nozzle. 
     Example 8 is a quick disconnect fitting comprising: a quick disconnect plug comprising: a fluid channel; a fluid inlet, and a valve assembly comprising: a pintle; and a valve nozzle comprising an outlet, the pintle and valve nozzle defining a valve channel, the valve channel having a volume that can decrease in response to high-pressure fluid entering the fluid inlet; the valve assembly residing within the fluid channel; and a quick disconnect socket to receive the quick disconnect plug, the quick disconnect socket comprising a socket stem to contact the valve assembly and push the valve assembly into the fluid channel upon the quick disconnect socket receiving the quick disconnect plug; the quick disconnect fitting to carry liquid to cool one or more processor units in a computing system. 
     Example 9 comprises the quick disconnect fitting of Example 8, wherein the socket stem comprises a seating surface to contact the valve assembly and a high-pressure relief surface cut into the seating surface, the high-pressure relief surface to allow high-pressure liquid to contact the pintle. 
     Example 10 comprises the quick disconnect fitting of Example 8, wherein the quick disconnect socket comprises a plunger, the quick disconnect plug to push against the plunger when the quick disconnect plug is received into the quick disconnect socket. 
     Example 11 comprises the quick disconnect fitting of Example 8, wherein the valve assembly comprises a pintle spring between the pintle and the valve nozzle. 
     Example 12 comprises the quick disconnect fitting of Example 8, wherein the pintle comprises a low-pressure fluid bypass channel. 
     Example 13 comprises the quick disconnect fitting of Example 12, wherein the low-pressure fluid bypass channel extends from a surface of the pintle into the valve channel. 
     Example 14 comprises the quick disconnect fitting of Example 8, the quick disconnect plug comprising a plug spring in the fluid channel, the valve assembly residing between the plug spring and the fluid inlet, the socket stem to push the valve assembly against the plug spring when the quick disconnect plug is connected to the quick disconnect socket. 
     Example 15 comprises the quick disconnect fitting of Example 14, the valve assembly to slidably move toward the plug spring in response to high-pressure fluid entering the fluid inlet. 
     Example 16 is a computing system comprising: a quick disconnect plug comprising: a fluid channel; a fluid inlet; and a valve assembly comprising: a pintle; and a valve nozzle comprising an outlet, the pintle and valve nozzle defining a valve channel, the valve channel having a volume that can decrease in response to high-pressure fluid entering the fluid inlet, the valve assembly residing in the fluid channel; and one or more processor units cooled by liquid that enters the quick disconnect plug. 
     Example 17 comprises the computing system of Example 16, the quick disconnect plug further comprising a plug spring within the fluid channel, the valve assembly residing between the plug spring and the fluid inlet. 
     Example 18 comprises the computing system of Example 17, the valve assembly to slidably move toward the plug spring in response to high-pressure fluid entering the fluid inlet. 
     Example 19 comprises the computing system of Example 16, wherein the valve assembly comprises a pintle spring between the pintle and the valve nozzle. 
     Example 20 comprises the computing system of Example 16, wherein the pintle comprises a low-pressure fluid bypass channel. 
     Example 21 comprises the computing system of Example 16, further comprising an O-ring surrounding a portion of the pintle or a portion of the valve nozzle. 
     Example 22 comprises the computing system of Example 16, wherein the computing system is located in a rack. 
     Example 23 comprises the computing system of Example 22, wherein the quick disconnect plug is connected to a quick disconnect socket that is connected to a supply manifold that supplies cooling liquid to one or more additional computing systems in the rack. 
     Example 24 is a quick disconnect plug comprising: a fluid channel; a fluid inlet; and a pressure regulation means located within the fluid channel to maintain a fluid pressure downstream from the pressure regulation means under varying fluid pressures upstream from the pressure regulation means. 
     In the description and claims, the terms coupled and connected, along with their derivatives, may be used. In particular examples, connected may be used to indicate that two or more elements are in direct physical or electrical contact with each other. Coupled may mean that two or more elements are in direct physical or electrical contact. However, coupled may also mean that two or more elements may not be in direct contact with each other, but yet may still cooperate or interact with each other. 
     Reference in the specification to “one example” or “some examples” means that a particular feature, structure, or characteristic described in connection with the example is included in at least an implementation. The appearances of the phrase “in one example” in various places in the specification may or may not be all referring to the same example. 
     Although examples have been described in language specific to structural features and/or methodological acts, it is to be understood that claimed subject matter may not be limited to the specific features or acts described. Rather, the specific features and acts are disclosed as sample forms of implementing the claimed subject matter.