Would you like to know what types of hydraulic fittings are available? Then this article will help you find the answers you need. (If you don't know what a hydraulic fitting is, then you need to read this article - what is a hydraulic fitting)
Types of Hydraulic Fittings
There are many types of hydraulic fittings, so we have listed all types of hydraulic fittings for your convenience.
Hydraulic Fittings by Link Type
Hydraulic fittings are attached via a number of different connection methods, each with its own conveniences and advantages.
Compression Fittings
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Compression fittings include all types of fittings which use compressive force to connect the vessel to the fitting.
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Standard compression fittings use metal gaskets, rings, or ferrules which form a seal on the vessel through compression. The compression is typically made by tightening a nut onto the fitting over the piping and ferrule, compressing, and securing the vessel inside. Standard compression fittings do not require tools to assemble, making them convenient for quick field installations.
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Bite-type fittings are compressive fittings with a sharpened ferrule that "bites" the vessel when compressed and provides the seal. Bite-type fittings, like standard compressive fittings, require no special tools to assemble but provide a stronger, higher pressure connection.
Mechanical grip fittings are two-ferrule assemblies. The back ferrule grips the vessel while pressing up against the front ferrule, which spring-loads the front ferrule and creates a seal between the piping and fitting body. These fittings can be reassembled multiple times without damaging components or piping. They have good resistance to mechanical vibration.
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Flare fittings consist of a body with a flared or coned end. Special flaring tools are used to install the vessel inside the flared end, providing a deep seal. Flare fittings can handle higher pressures and a wider range of operating parameters than standard compression fittings.
Crimp Fittings
Crimp fittings involve placing a hose over a tubular end and crimping against it with a sleeve, ring, or crimp socket. These fittings typically require crimping tools or machines to make the connections.
End Fittings
End fittings provide specific surfaces for connecting vessels in hydraulic systems.
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Clamp ends are fittings that allow hoses or tubes to be clamped over the part.
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Plain ends are fittings with surfaces that allow pipes or tubes to be connected by adhesive, solder, welding, or other permanent means. Welding, when done properly on compatible materials, provides a strong and reliable connection.
Flange Fittings
Flange fittings are rims, edges, ribs, or collars with flush surfaces perpendicular to the attached pipe or tube. These surfaces are joined and sealed via clamps, bolts, welding, brazing, and/or threading. For more information on flanges, visit the Pipe Flanges Selection Guide on GlobalSpec.
Push-to-Connect
Push-to-connect fittings have ends that are designed to accept tubing by pushing it into the end. These fittings typically disconnect via some type of collar retraction. These connections are convenient for sections of the system requiring frequent disconnection and reconnection.
Threaded Fittings
Threaded fittings have screw threads (built-in groo ves) on their inner (female) or outer (male) surfaces designed to accept connections with matching threads. Threads that provide a simple connection but no seal are called straight threads. Tapered threads are designed to provide a tight seal for gases or fluids under pressure. Seal reliability can be improved by adding a coating or seal tape (Teflon). Especially precise threads are called "dry fit", meaning they seal without the need for an additional sealant, which is important in applications where sealant addition could cause contamination or corrosion.
Hydraulic Fittings Are Classified by Function
There are a vast number of types of fittings installed in hydraulic systems which perform different functions. The most common types are described in the table below:
- Fittings that extend or terminate pipe lengths:
Adapter, Coupling, Sleeve, Union, Cap, Plug
- Fittings that add or change direction:
Elbow，Tee，Cross
- Fittings that connect pipes of smaller size:
Reducer
- Fittings that provide special connections or functions:
Nipple，Valve
Hydraulic Fittings Are Classified by Material
- Steel Fittings:
Steel fittings are made by a combination of iron with other elements to make it more durable and heat resistant, for instance, carbon steel can tolerate a temperature range from -65°F to 500°F.
- Brass Fittings:
Brass has greater strength and durability as compared to stainless steel. They provide a leak-proof seal and can operate under pressure up to 3000 psi, however, lower pressure is recommended for the fittings made from brass.
- Plastic Fittings:
They are usually not considered suitable for hydraulic systems because they have lower strength and durability. It has good resistance to corrosion and is lower cost.
- Stainless Steel Fittings:
They are great and considered suitable for high pressure, as well as high-temperature applications. They can operate in temperatures ranging from -425°F to 1200°F. They have excellent resistance to corrosion in extreme environmental conditions and are durable.
- Aluminum Fittings:
They are corrosion resistant and lighter in weight as compared to steel. They are usually used in automotive industries.
Why Are There So Many Different Types of Hydraulic Fittings?
While there might be hundreds if not thousands of hydraulic fittings and connectors, they all boil down to three basic types. These three types are either metal seal, soft seal, or tapered thread connectors. No matter which of these types of fittings yours belongs to, it will be required to satisfy two conditions: it must seal and it must hold.
In some cases, the same mechanism can fulfill both functions, and in other cases, two different parts of the same mechanism will handle the necessary functions. Tapered pipe connectors are cut on a taper with a pipe’s diameter, and it changes along the entire threaded portion of a pipe, in order to make the connection tighter. These types of fittings require a sealer, so you can be sure there will be no leakage around the fitting, and this is usually accomplished with a chemical sealant or a tape sealant.
Do You Need to Buy Hydraulic Fittings?
If you're still not sure which fittings and connections you need for your device, we can help. Contact us at XCD Hydraulics so we can provide you with the exact fitting for your needs.
References
- https://www.globalspec.com/learnmore/flow_control_fluid_transfer/pipe_tubing_hose_accessories/hydraulic_fittings
- https://www.thomasnet.com/articles/hardware/types-of-hydraulic-fittings/
- https://www.hydraulicsdirect.com/hydraulic-fittings_a/337.htm
- https://sapphirehydraulics.com/how-to-identify-the-hydraulic-hose-fitting-you-need/
