The Right Terminations for Reliable Liquid Cooling in HPC

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liquid cooling

This guest post from CPC explores the right terminations for liquid cooling in HPC, as well as why HPC manufacturers are increasingly deploying liquid cooling.

liquid cooling

High performance computing manufacturers are increasingly deploying liquid cooling. To avoid damage to electronic equipment due to leaks, secure drip-free connections are essential.

Quick disconnects (QDs) for HPC applications simplify connector selection and have terminations that fall into two categories: barbs for tubing or threaded joints.

Hose Barb Connections

Quick-disconnect couplers with barbed terminations work well for applications with flexible tubing. Barbed terminations grip the inside of tubing by expanding over the hose barb termination and then relaxing to its original diameter, creating a leak-free connection.

It’s important to find the barb connection that best suits the tubing and application.

  1. Triple barb. Fluid coupling terminations with multiple, shallow barbs are commonly used with lighter weight tubing. The triple barb design offers good retention with redundant sealing points.
  2. Locking barb. The locking barb is a good choice in environments where heavy tubing may be exposed to hose or assembly pull (being bumped or stepped on). Locking barbs fit securely without the need for hose clamps or ferrules and work well on heavy-duty tubing like EPDM.
  3. Compression. Common compression style terminations include a ring or ferrule to mate with rigid tubing and a nut to thread capture the ferrule against the termination seat.

Threaded Port Connections

Fluid couplings incorporating a threaded termination provide a reliable connection primarily at machined ports throughout the cooling loop.

Straight thread terminations for liquid cooling applications will most often incorporate an elastomeric seal to achieve a leak-free connection.

Tapered pipe thread terminations on the other hand, do not include an additional elastomeric component. The threads themselves both retain the part and create a seal. However for reliable sealing performance, thread tape or additional sealant is recommended to fill gaps between threads and aid assembly.

Common threaded terminations include:

  1. SAE Straight Thread O-Ring (ORB). This parallel thread termination features elastomeric sealing and is commonly used in North America. The mating female port requires specific machining to create a chamfered seat at the top that accepts an O-ring.
  2. NPT (National Pipe Thread). This common tapered thread is relatively easy to install—just drill and tap a mating port. However, a thread sealant (tape or compound) is required to fill in surface imperfections to create a leak-free seal.
  3. G/BSPP (British Standard Pipe Parallel). Most commonly used in Europe and Asia, this straight-thread, metric termination has a 55° flank and Whitworth thread form. While metal-to-metal sealing is covered in the standard specification, the most common sealing method will include an elastomeric seal.
  4. R/BSPT (British Standard Pipe Taper). This termination provides a simple, leak-free connection. Consistent with other tapered thread installations, tape or additional liquid sealant is recommended to ensure reliability.

QDS Specifically for Liquid Cooling

All terminations mentioned above are available in quick disconnect (QD) couplings, which allow fast, secure, repeated connections and disconnections during service and use. Integrated non-spill shutoff valves automatically stop flow, reducing spills or pressure loss during disconnection.