What is an ORB Fitting?
Commonly known as the O-ring boss (ORB), these types of fittings are defined by the SAE J1926 standard. It defines the dimensions for both the male and female parts.
The male part consists of threads given by the Unified Thread Standard (UNF/ASME B 1.1) with a groove for the placement of an O-ring. The female part has a seat or chamfer from where the threads begin. When the two parts are connected, the rubber-like O-ring compresses between the two seats of the male and female parts. This allows for an extremely tight seal between the two parts, compensating for the dimensional variations.
Given the variation of standards employed for fluid conveyance throughout the world, one may require a fitting with ORB fittings at one end and NPT, NPS, AN, or JIS at the other. They are commonly manufactured using high-strength carbon or stainless steel to withstand the high-pressure applications they are used in.
Thread Description
The thread is defined in the format #X – YY UNF, where X is the major diameter (Dmaj) that identifies the thread length, and YY is the pitch that defines the distance between each thread. Each thread has an angle of 60O.
Dmaj is given by the following formula: Dmaj = X × 0.013 in + 0.060 till X =12, and is measured in inches while the pitch is defined by thread per inch (TPI). For X > 12, X itself defines Dmaj. Below are some common thread sizes.
Advantages of ORB Fittings
They are many advantages of using ORB fittings. The fact that they’re widely available offering a combination of unions, tees, swivels, and bends for use in various applications. The O-ring allows for an extremely tight seal that can withstand high pressures, useful for hydraulic and other automotive applications. The room for play allows them to be reassembled multiple times without leading to cracks or deformation due to overtightening.
Disadvantages of ORB Fittings
Ironically, their strongest element, the O-ring, is also their weakest point. To use them at high pressures, they must be able to withstand the temperature as well. The fitting itself is made from high grades of steel capable of withstanding high temperatures, but the O-ring may melt or crack and lead to leaks. It must also be compatible with the media carried; otherwise, the O-ring may erode and lead to a failure in connection.
According to the sizing table above, multiple thread standards come with the same pitch; hence selecting an undersized fitting may lead to loose-fitting. Additionally, selecting a longer fitting than specified may lead to an improperly compressed O-ring.
Frequently Asked Questions
What fittings are required for a data center liquid cooling system?
Data center liquid cooling systems typically require stainless steel adapters, elbows, tees, reducers, isolation ball valves, flexible hose connections, and quick disconnect couplings.
These components connect coolant distribution units (CDUs), secondary fluid network headers, rack drops, manifolds, and server-level cooling equipment.
Titan Fittings supplies 304 and 316L stainless steel connection components for data center liquid cooling infrastructure, helping customers source compatible fittings, valves, and couplings for cooling loop installations.
Why are 316L stainless steel fittings used in data center liquid cooling?
316L stainless steel is frequently selected for data center liquid cooling because of its corrosion resistance, mechanical durability, and compatibility with many water-based coolant systems.
Its low-carbon composition also helps reduce sensitization-related corrosion concerns associated with certain welding operations.
Titan Fittings offers 316L stainless steel fittings for cooling infrastructure where reliable connections and appropriate material compatibility are essential.
Final material selection should account for the coolant formulation, corrosion inhibitors, and operating conditions.
What components connect a secondary cooling header to a server rack?
A typical rack-drop assembly uses a branch connection from the cooling header, size-reduction fittings, isolation ball valves, flexible hose assemblies, and appropriate quick disconnect couplings.
These components connect the secondary fluid network's supply and return headers to the rack-level cooling equipment.
Titan Fittings supplies stainless steel transition fittings, full-port isolation valves, flexible hose connections, and OCP Large Quick Connectors (LQCs) for rack-drop applications.
What is the difference between LQC and UQD quick disconnects?
LQC (Large Quick Connector) and UQD (Universal Quick Disconnect) couplings are used in different areas of data center liquid cooling systems.
LQC couplings are designed for larger-flow connections such as rack drops and certain CDU-to-manifold interfaces. UQD couplings are generally used for smaller, server-level cooling connections inside the rack.
Titan Fittings supplies quick disconnect solutions for both infrastructure and in-rack applications, helping customers select connections based on location, flow requirements, and serviceability.
What role do isolation ball valves play in liquid cooling systems?
Isolation ball valves allow individual cooling branches, racks, or equipment sections to be shut off for maintenance without necessarily draining the entire coolant distribution loop.
Full-port ball valves are commonly selected to minimize flow restrictions and pressure losses.
Titan Fittings supplies stainless steel isolation ball valves for rack-drop and cooling infrastructure applications where dependable coolant shutoff and system serviceability are essential.
Proper isolation procedures must still be followed before disconnecting or servicing equipment.
What fittings are compatible with PG25 and deionized water coolants?
304 and 316L stainless steel fittings are commonly used with PG25 propylene glycol solutions, deionized water, and other formulated water-based coolants when material compatibility requirements are satisfied.
However, compatibility depends on more than the metal. Seal materials, corrosion inhibitors, fluid chemistry, and operating temperature must also be evaluated.
Titan Fittings supplies stainless steel cooling fittings for these applications and recommends verifying seal compatibility and coolant manufacturer requirements before final specification.
More questions: Data Center Liquid Cooling Fittings & Components