How to Select the Right Hydraulic Fittings and Couplers

While hydraulic fittings and couplers may not be the most attention-grabbing products, they play a crucial role in maintaining the safety and efficiency of your hydraulic system. Choosing the right hydraulic fitting or coupler is vital, and with so many types available, it can be a challenge to identify the best fitting for your specific application

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Hydraulic fittings are available in hundreds of configurations &#; in fact, there are too many types to cover in a single article. That&#;s why for the purposes of this blog post, we will focus on those most relevant to users of hydraulic tools; such as cylinders, cutters, and torque wrenches. We will look at the different types of fittings and couplers, what can go wrong, and things to consider when making your selection.

What are hydraulic fittings? 

If you&#;re new to hydraulics, let&#;s define what we mean by a fitting. Simply put, hydraulic fittings connect hoses and pipes to other system components such as tools, valves, and pumps. If you use Enerpac hydraulic tools the most common types to be aware of are: 

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What makes a good hydraulic fitting? 

Essentially, a good hydraulic fitting is one that&#;s appropriate for the specific application. This means choosing the right pressure rating, material, diameter, thread/connection type, and size.

A fitting should be easy to install and remove and should not require specialized tools or excessive force. If you&#;re choosing a coupler and your main priorities are a quick connection with minimal oil spillage it may be worthwhile paying extra for a flat face push-fit coupler.  

Also, if the coupler doesn&#;t come supplied with a protective dust cap be sure to get one &#; especially if you work at dirty industrial/construction job sites. 

What makes hydraulic fittings and couplers fail? 

When used correctly, hydraulic fittings and couplers are unlikely to fail, but its worth taking extra care to avoid the following: 

Improper installation: A poorly installed fitting can lead to leaks or even the complete failure of a whole hydraulic system. Over-tightening fittings beyond the recommended torque can cause damage to the fitting, leading to leaks. Don&#;t be tempted to use tools for couplers designed to be tightened by hand. In addition, if a coupler is not properly aligned with the hydraulic fitting this may also create stress and a risk of fatigue or damage. 

Contamination: If dirt, dust, or other contaminants get into the hydraulic fluid, they can clog the coupler and prevent it from functioning properly. This is more of a potential issue for tool users out in the field and less so for factory-based hydraulic work-holding situations. 

Impact damage: Physical damage to a coupler can cause it to become deformed, which can prevent it from operating correctly. 

Vibration: Vibration over extended periods can cause fittings to loosen over time, leading to leaks or failure. Vibration can be caused by hydraulic pumps and cavitation within the hydraulic fluid. 

Over-pressurization: If the pressure in the hydraulic system rises higher than what the coupler is designed to handle this may cause it to fail.  

Corrosion: Over time, in harsh conditions, hydraulic fittings can corrode due to exposure to moisture, chemicals, or other environmental factors. This has the potential to weaken the fittings which could lead to leakage or failure. 

Fatigue: Repeated cycles of pressure and stress can cause fatigue in the fittings, leading to cracks and failure. 

Wear and tear: Over time, fittings and couplers that include seals may become worn and therefore lose their ability to maintain a tight seal. 

Selecting Hydraulic Fittings: 5 Key Considerations  

Pressure &#; Check the maximum rated pressure needed. Components used with hydraulic tools are classified as high-pressure and typically rated for either or psi (350 or 700 bar). The fittings supplier should make this clear in their catalogs or on their website. 

Flow Rate &#; The type and size of the tool will determine the flow needed. If you need a high-flow coupler, consider the Enerpac C (cone) type or F (flat face) type. These allow for up to 4 times more flow than many standard couplers.  

Thread Type &#; These vary by region throughout the world, so make sure your fittings, tools, and hoses are compatible. If they&#;re not, an adapter or reducer may be available to solve the issue. Buying your hydraulic tools and hose connectors from a single manufacturer will help to avoid incompatibility issues. 

Coupler Connection Type &#; Choose between the common type with a threaded sleeve to hand tighten, and &#;push to fit&#; flat face types that save time and minimize oil loss and spillage.  

Material &#; The material of the fitting can influence its pressure rating and ability to withstand harsh and corrosive working environments. Also, bear in mind it&#;s not good practice to mix some metal types because of potential galvanic corrosion.  

What are the standard sizes? 

Hydraulic fittings are available in many different sizes. However, if you are using Enerpac hydraulic tools the standard fittings and couplers will most likely be ¼&#;  or 3/8&#;, with NPTF or SAE thread types. 

Identifying Hydraulic Fittings 

A visual check of the type and size of the fitting is the first obvious step. However, when it comes to threads, at first glance these can all look the same. Fortunately, there are ways you can narrow down the possibilities. See more on the Parker blog here.

Check to see if the thread is tapered.

First, look at the fitting from the side view to see if the thread is tapered or parallel. A tapered thread will get smaller in diameter towards the end. If you cannot tell this immediately, try using vernier calipers. The next thing you can do is check the thread pitch with a pitch gauge.

Finally, determine the nominal size by measuring the outside diameter or checking against a thread profile gauge. If you have a selection of known threaded fittings handy, checking to see how well these connect can also help.

Types of Hydraulic Couplers

A hydraulic coupler makes quick connections to your hydraulic system and typically includes male and female halves which can be connected by hand. For example, the C-Series Coupler is the standard on most Enerpac pumps and cylinders up to 10,000 psi (700 bar). You can buy them as a complete set or individually as male and female halves. Where multiple connections are needed, such as with split flow and other controlled lifting pumps, hydraulic couplers should be quick and easy to make a secure connection.

Types of Hydraulic Couplers for Enerpac Cylinders and Other Tools

Standard Regular Couplers

Common sizes of this type are ¼&#; &#; for use with small hydraulic cylinders and pumps. Some larger tools and medium-duty applications will most likely need a larger 3/8&#; coupler. Whichever you choose, the maximum flow capacity will be around 462 in3/min.

High Flow Couplers

These are available in cone or flat face types. The cone type is less prone to back pressure than other types such as ball-style couplers. On the downside, they leak a little oil when disconnecting. The alternative solution is the more expensive flat face type click fit type, which is very much leak free.

Flat Face Hydraulic Couplers

These high-flow couplers feature a quick push to connect operation and also prevent spillage of hydraulic fluid. Although these are a simple push-fit design, users should not be concerned about their safety as they are recognized by the Hydraulic Tool Manufacturers Association for safety and performance. F-Series Flush Face couplers from Enerpac are 3/8&#; and allow a generous flow capacity of in3/min (40 l/min).

Torque Wrench Couplers

As the name implies, these are for use with hydraulic torque wrenches such as the Enerpac S-, W-, RSL-, DSX-, and HMT-Series. These are used with THQ-Series twin torque wrench hoses. They are usually ¼&#; unlike the large 3/8&#; couplers used for hydraulic cylinders and pumps.

Types of Fittings

Common fitting types for use with hydraulic tools and systems.

Adapters and Reducers

Hydraulic adapter fittings are used to connect hydraulic hoses, tubes, and pipes of different sizes and types. Example uses are to connect different thread sizes or connector types, for example, from male to female threads or from NPT (National Pipe Thread) threads to SAE #4 (Society of Automotive Engineers).

Fixed Couplings

A fixed coupling simply attaches two same-sized threaded components together using female threads. A hexagonal section in the center enables the coupling to be held while attaching.

Elbow, Tee, and Cross-Fittings

Other fixed fittings for more permanent connections. Used for changing flow direction or adding an extra connection.

Dust Caps for Hydraulic Fittings and Couplers

Dust caps for hydraulic couplers prevent dirt from entering the system which could cause the coupler to fail, or lead to premature wear of internal components. Types include push-fit plastic dust caps, (sometimes with a 2-in-1 configuration for both male and female haves), and also metal screw-on caps. Both types include a retaining strap or chain to keep it attached to the tool or hose fitting.

Coupler Bleed Tools 

Considering the high pressures involved when using hydraulic tools, the risks of injury caused by projectile parts and under-skin hydraulic fluid injections are high if couplers are incorrectly used. A coupler bleed tool like the CT604 relieves hydraulic back pressure by safely bleeding the high-flow hydraulic coupler. The CT-604 is compatible with C Series couplers and works by slow hand rotation of the knob. This applies a force onto the ball or cone inside the coupler. Once the ball or cone is pushed from its seat the pressure is relieved. Read more about safe depressurization in this blog post.

Where to Buy Hydraulic Fittings and Couplers

If you are looking for hydraulic fittings to use with Enerpac tools you can get these from your nearest Enerpac distributor. If you&#;re based in the United States, you can buy hydraulic fittings online directly from Enerpac.

Conclusion

In summary, a &#;good&#; hydraulic fitting is one that matches the application, with the most important selection criteria being operating pressure, thread/connector compatibility, flow rate, and material compatibility. If you select fittings and couplers from the same manufacturer or distributor that you got your hydraulic tools from this should be easier than shopping around.

Most importantly, to ensure safety, you must install and disassemble your fittings correctly, which means using the specified torque for threaded fittings and always depressurizing the system before removing any coupler or fitting.

 

This article will fit you like a glove. I will explain in 5 minutes what types of hydraulic fittings exist.

Hey, a word of advice!

Link to zkhthydraulics

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As you read the article, click on the different types of fittings. It will open a new tab to see each type in more detail. I know you love to know more.

So, let&#;s go!

What is a hydraulic fitting?

A quick definition of fitting:

Fittings are mechanical elements that allow two or more pipe or hose elements to be connected safely and efficiently. There are several types of fittings used in different applications and environments, each with its own characteristics and benefits.

Hydraulic fittings are a special type of fitting used in hydraulic systems to connect pipes and hoses that carry fluids normally under high pressure. These hydraulic systems are in a wide variety of applications, from heavy machinery, process industry, and construction vehicles to industrial production equipment and lifting and handling systems.

We design Hydraulic fittings to withstand high pressures and temperatures. They provide a tight, secure connection in demanding working environments.

They can be made from a variety of materials, such as stainless steel, brass, aluminum, or plastic. In addition, they can be available in a variety of shapes and sizes to suit the needs of each application (straight, elbow, tee, cross&#;).

Let&#;s get down to what is interesting, as I guess it is already clear to you what a fitting is.

Types of hydraulic fittings

They are divided into two main categories: high-pressure fittings and low-pressure fittings. High-pressure fittings are used in systems that convey fluids at high pressure, such as hydraulic systems of heavy machinery or drilling equipment.

Low-pressure fittings are used in systems that convey fluids at low pressure, such as lubrication systems. They are connected to pipes and hoses by different methods, such as threading, compression, or mechanical bonding.

They can also have different shapes, such as straight fittings, elbows, tees, or cross fittings. These allow pipes and hoses to be joined at different angles and configurations. It is important to select the right type of hydraulic fitting for each application to ensure a secure and durable connection.

In addition, hydraulic fittings must be installed and maintained correctly to prevent leaks and damage to the system. In summary, hydraulic fittings are a key component in hydraulic systems. They are essential to ensure the safe and reliable operation of the equipment and machinery that use them.

Let&#;s look at the different types in a little more detail.

A double-ring compression fitting, also known as a compression union fitting, double olive fitting or double ferrule, or &#;Swagelok&#; fitting, is a type of fitting used in piping and hose systems to create a secure, leak-tight connection. This type of fitting is commonly used in medium or high-pressure fluid handling applications.

Simply connect them to the pipe and tighten them with a wrench or open-end wrench to achieve a watertight connection.

One of the advantages of double-ring fittings is that they are relatively easy to install and do not require soldering glue, or special tools.

Another advantage of double-ring fittings is that they are very versatile and can be used with different sizes of pipes and hoses, such as copper, stainless steel, and plastic tubing. It is important to make sure that the double ring fitting is compatible with the type of tubing used and that it is seamless.

And, stay tuned, because I have all the sizes and fittings you need. Elbows, reducers, crosses, tees, valves, sleeves, and many more. In addition, I manufacture them in 316/L stainless steel. They can also be manufactured in 904, Alloy 20, Duplex, Superduplex, Incoloy, Hastelloy, Inconel, Monel, or other materials upon request.

And if you want the technical data sheet of the double ring fitting, don&#;t be shy and click on download:

FICHA TÉCNICA DOUBLE RING FITTING EN

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ASME hydraulic fittings

ASME B16.11 , and PSI fittings are a type of high-pressure fitting used in industrial applications where a secure, high-pressure resistant connection is required. These fittings are designed and manufactured to American Society of Mechanical Engineers (ASME) B16.11 specifications. They are available in different sizes and shapes to suit the needs of each application.

The number used to describe these fittings (, , and PSI) indicates the ASME pressure rating they can withstand. ASME B16.11 PSI fittings are suitable for high-pressure applications requiring a maximum strength of up to pounds per square inch. ASME B16.11 PSI fittings are suitable for even more demanding applications requiring a maximum strength of up to pounds per square inch. Finally, ASME B16.11 PSI fittings are the strongest. They are used in applications requiring a maximum strength of up to pounds per square inch.

This standard covers NPT and Socket Weld connections, although we also have them in BSPP.

And if you want the ASME Fittings datasheet download it in a second here:

FICHA TÉCNICA ASME FITTINGS EN

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As you can see, I am giving you little gifts with the technical data sheets. In the end, it is all very well to know what each one is, but it is necessary to know more in detail.

Let&#;s go to the single-ring fitting.

Redfluid&#;s single-ring fittings are designed for joining pipes and tubing in hydraulic systems and comply with the Deutsches Institut fϋr Normung DIN / ISO -1 standard. These fittings are available in different sizes, from 4 to 42 mm OD, to suit different tubing or pipe diameters. Depending on the series and pipe diameter, these fittings can withstand up to 800 bar.

The range of single-ring fittings includes a wide variety of shapes, such as straight, cross, tees, elbows, mixed male or female x-ring thread, wall bushings, and weld fittings, among others. These fittings are available in two standard materials: 316 stainless steel and carbon steel.

In summary, Redfluid&#;s single-ring fittings are a reliable solution for connecting pipes and tubing in hydraulic systems and are available in different sizes and shapes to suit the needs of each application. In addition, their ability to withstand high pressures makes them ideal for applications that require additional strength.

If you are interested in seeing the difference between a single ring fitting and a double ring fitting in much more detail, you can click HERE.

And as in any case, here is the technical data sheet of the single ring:

FICHA TÉCNICA SINGLE RING FITTINGS EN

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Hydraulic quick and automatic fittings

There are two types of automatic and quick fittings available: Push-in fittings and push-on fittings.

• Push-On Fittings: They consist of an outer metal nut and a small inner nipple. The tube is inserted into the nipple and tightened with the outer nut.

• Push-In Fittings: The tube is inserted into the push-in fitting and an outer ring, which is usually red or blue plastic, holds the tube without the need to tighten any nuts. They are also called &#;Festo&#; type.

Both types of fittings are available in brass or stainless steel and can be found in a wide variety of shapes and forms, and in different threads, including BSP, BSPT, NPT, and metric. They are also available in different dimensions, from 4 mm to 16 mm outside diameter (OD).

If you are a fan of this type of fittings, I recommend downloading the quick and automatic fittings datasheet:

FICHA TÉCNICA AUTOMATIC FITTIGNS EN

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High-pressure hydraulic fittings

There is a wide range of products that are suitable for working pressures above 400 bar, up to bar. For high pressures, special connections known as &#;cone & thread&#; MP (Medium Pressure) or &#;cone & thread&#; HP (High Pressure) are used. MP products normally work up to bar, while HP products can work up to bar.

Needle valves, ball valves, and check valves are included, as well as fittings in different shapes, such as elbows, tees, sleeves, and plugs. In addition, the fittings are available in Male x Male, Male x Female, or Female x Female versions. It is one of the typical fittings for hydrogenerators or high-pressure hydrogen pipelines. The connection is watertight and high pressure. These fittings can only be connected to pipes with specially coned ends compatible with the rest of the fittings. We provide a complete solution for the coning of any installation and we supply already coned according to your lengths.

They are usually manufactured in 316 stainless steel. If you do not find the adapter you are looking for, we can manufacture it for you.

You can also download the technical data sheet of the high-pressure fittings and valves. And this is the last of this article:

FICHA TÉCNICA HIGH PRESSURE FITTINGS EN

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Certificates for hydraulic fittings

This part is very useful, either way aim well.

In the industrial world, the safety and reliability of equipment and systems are of vital importance to ensure process quality and efficiency. In this regard, fittings and other pipe fittings must comply with a number of norms and standards to ensure their quality and performance.

• Certificates for double ring fittings: EN 2.2 or 3.1
• Certificates for ASME fittings: EN 3.1, EAC (GOST TRCU), SHELL, PEMEX, BP, REPSOL, TOTAL, ENI, PED 97/23CE and PED /68/EU approvals.
• Certificates for single ring fittings: EN 2.2 or 3.1
• Certificates for push-in and push-in fittings: /, /65/EC, NSF/ANSI169, PED /68/EU, SILCON FREE, MOCA / CE, ISO :
• Certificates for high-pressure fittings: EN 2.2 or 3.1

Well, I don&#;t want to go on any longer, otherwise I&#;ll be labeled as tedious.

I hope this article has been useful for you to better understand the different types of fittings and their characteristics.

If you have any questions or need more information about our products or services, do not hesitate to contact us. We are at your disposal to help you in everything you need and offer you the best solution for your specific application.

Contact us to discuss your requirements of interlock din hydraulic fittings. Our experienced sales team can help you identify the options that best suit your needs.