Hydraulic quick couplings can be some of the most overlooked components in many applications. While selecting the proper couplings may seem like a task you wouldn’t need to think twice about, there is a surprising amount of research that goes into purchasing the correct hydraulic couplings.
First, you need to identify what the coupling’s main goal will be within the application, then think about the various types of hydraulic couplings that are available and what makes them different. Finding the difference can allow you to zero in on your application’s specific requirements and make the best choice for you. Here are some things to consider when deciding on what couplings fit your needs.
What are hydraulic couplings?
Hydraulic couplings give users the ability to quickly and safely connect and disconnect various hydraulic lines at critical points within the hydraulic system. The coupling sets are made up of two halves – a male nipple and a female coupler, both of which are typically valved in hydraulic applications to automatically stop and start flow during connection and disconnection.
Hydraulic coupling valves: to have or not to have
Based on the presence of valving in the coupling, hydraulic couplings generally fall into one of two groups, either double shut-off or straight-thru.
Double shut-off couplings are used extensively when it is important to minimize fluid loss upon disconnection. Both halves of the coupler, the body, and the nipple, contain shut-off valves. These valves open automatically when the body and nipple are connected and close automatically when the two halves are disconnected—keeping fluid loss to a minimum.
Straight-thru couplings have no valves in either half and are ideal for maximum flow applications, such as water. Their smooth, open bore offers the lowest pressure drop of any quick disconnect coupling and allows them to be thoroughly cleaned. Since there are no valves in either half, the fluid flow should be shut off before the coupling is disconnected.
What are the different types of hydraulic couplings?
Manual connect
These couplings offer the ability to connect and disconnect in hydraulic applications with no tools. The user must pull the sleeve back while making a connection, so this is commonly a two-handed operation.
Screw-to-connect
Also known as thread-to-connect, screw-to-connect couplings have a threaded design. The male nipple has the external threads, while the female coupler contains the receiving threads on the interior of the sleeve. These threads reduce accidental disconnection associated with vibration and movement making screw-to-connect couplings the ideal choice for high pressure, high cycle applications.
Push-to-connect
Push-to-connect couplings offer a simple and easy connection. Simply push the two halves together without the use of any tools. The user does not need to pull the sleeve back during connection, so this is commonly a one-handed operation. These couplings are good for applications that require repeated connection and disconnection.
Non-spill
Non-spill couplings are designed to minimize spillage and air inclusion when disconnecting due to their flat face valve design.
How to choose a hydraulic coupling for your application
When selecting the correct coupling, use Parker's proven STAMP process:
Size:
Hydraulic couplings come in different sizes. Knowing the size that you need based on your system and other components, like hoses, pipes, pumps, etc., is key to choosing the right coupling. Selecting the wrong size can impact proper flow velocity resulting in sluggish system performance or excessive pressure drops, damage, and leaks. You can narrow down size selection based on your system's flow rate and acceptable levels of pressure loss.
Temperature:
Identify two temperatures when selecting a coupling – ambient temperature (temperature outside) and media temperature (temperature of the media conveyed through the system). Parker offers a variety of different seal materials to meet different temperature requirements.
Application:
Answer questions about the application before purchasing a hydraulic coupling. Understanding if your application has dynamic or static pressure, high vibration/impulse, indoor/outdoor use, etc. Asking these questions upfront helps focus on choosing the best coupling set for your needs.
Media:
The product you order must be compatible with the fluid it conveys. Parker has a media/fluid compatibility chart that shows what fluids are recommended by coupling material.
Pressure:
When considering pressure, knowing both the system’s working pressure and any surge pressures and spikes is essential. Couplings rated pressure are provided so you can choose the right product for your system. Rated pressures for hydraulic couplings range from 30 to 15,000 psi. ISO 5598 defines rated pressure as, “the qualified operating pressures which are recommended for a component or a system by the manufacturer.” Parker-rated pressures have been established based on laboratory tests which include, but are not limited to, static burst tests and multiple cycle impulse tests.
Learn more about Parker couplings
Not only does your Colliflower ParkerStore have the parts for almost all hydraulic applications, but also the product experts to help you determine the exact type of couplings you need for your system.
Our Colliflower product experts can walk you through the below Hydraulic Coupling Selection Checklist to determine the right couplings:
What are the functional requirements of the coupling?
What is the maximum working pressure of the application?
Which seals and body material are compatible with the system’s fluid?
Is the application static or dynamic?
What size coupler is required?
What is the maximum pressure drop suitable for the application?
Does the application require the ability to connect and disconnect under pressure?
What are the media temperature and ambient temperature?
What end configurations are required?
Is an industry interchange coupler required?
Are air inclusion and fluid loss concerns in the application?
The Wrap
When you need to select a quality coupler for your hose - no matter the job - visit your Colliflower ParkerStore for expert guidance to find your best solution! Or, Contact Us / Request a Quote today, and let us get you back to work - FAST!