Frequently Asked Questions

Questions About Products

What is Hydraulic Quick Couplings?
In hydraulic fluid power systems, power is transmitted and controlled through a liquid under pressure within an enclosed circuit. Quick couplings are used to join or separate fluid conductors quickly and without the use of tools or special devices. Hydraulic quick couplings are often used in hydraulic systems, but they are also used in fluid transfer, hydraulic testing, and other applications.
What is hydraulic quick coupling ISO standard?
ISO has developed a series of standards for hydraulic quick couplings. It mainly regulates the main dimensional requirements of quick couplings and the performance requirements in hydraulic power system applications. Quick release couplings conforming to ISO standards are half to half interchangeable. This allows the user to purchase any manufacturer’s quick release coupling to replace the quick release coupling on the equipment
How to choose the right quick coupling?

Quick couplings are a perishable part because they often need to be connected and disconnected. They often need to be replaced within a certain period of time. However, the original quick couplings are more expensive, so it is more convenient and reasonably priced to buy the market brand quick couplings.

There are several main requirements to find a quick coupling that you can replace.

  1. Most hydraulic equipment manufacturers use ISO standard quick couplings, so the user can identify the standard for quick release couplings and quickly help the user select a replacement quick coupling.
  2. The user can look up the standard and interchangeability of quick release couplings with other brands by using the number on the existing quick release coupling.
  3. The threads are used to connect the hose or equipment to the quick coupling, so the choice of threads is very important. Pipe threads are commonly used in quick couplings, BSP threads in Europe, NPT threads in North America, and some metric threads. The user needs to choose the correct thread to replace the quick coupling on their equipment.
Working pressure of quick coupling

The ISO standard specifies the performance requirements for quick couplings used in hydraulic power systems. Working pressure is one of the most important parameters. However, these standards only regulate quick couplings for hydraulic power systems, mainly made of carbon steel. The working pressure of quick couplings made of other materials, such as stainless steel or brass, is much lower. In general, the working pressures of quick couplings of the same type are similar, except for some special heat treatments, where the properties of the material are optimized.

How to identify quick couplings?

Quick couplings can be divided into several categories, the ball lock type usually conforms to ISO7241 and can be divided into series A and series B. Flat face quick couplings often conform to ISO16028, and threaded high-pressure quick couplings have ISO14540 and ISO14541. After knowing their standards, you can measure the diameter of the male connector and determine the body of the quick release coupling according to the ISO standard size requirements. The body size of the quick coupling can be determined by measuring the diameter of the male coupler.

What is the seal ring material for the hydraulic quick couplings?

Most quick couplings use seal rings to achieve a sealing effect. When a quick coupling is disconnected, there are usually valves on both the male coupler and female coupler ends to block fluid leakage. Usually, Poppet valves and flat face valves use a deformation of the seal ring to squeeze and achieve a seal. The ball valve does not need to use a seal ring, but it uses the deformation between the steel ball and the housing to achieve a seal. Because of the different fluid materials and operating temperatures, the seal material is very important for the selection of quick couplings in different environments. Choosing the wrong seal ring material can cause leaks or even accidents during using the quick couplings. Most quick couplings are used in hydraulic equipment, so the fluid is often hydraulic oil. Therefore, the default seal ring of most quick couplings is NBR, and the working temperature is generally recommended to be below 100˚C. When higher operating temperatures are required, we use FKM, and FFKM is often used in chemical fluids. If your application environment of quick coupling is special, please consult us first when you purchase quick coupling.

how to custom a quick coupling for special applicaiton?

In many cases, customers need custom quick couplings for their projects. Equipment manufacturers, for example, will customize quick couplings for their own equipment to differentiate themselves from other manufacturers. Sometimes some assembly dimensions of quick couplings need to be specially designed to fit with other accessories for installation. Or for newly designed hydraulic systems, hydraulic pipe connections, etc.
Regardless of how you need to customize your quick coupling, it is always best to have the connection dimensions of the quick coupling conform to ISO standards at the beginning of the design process. This will make it easy for the user to purchase replacement parts on the market during the subsequent service of the product. Make the product last longer. If there is a similar competitor’s design, you can send us the sample, through communication, we help you to update and improve the design according to your needs.

To custom a quick coupling, you need to think about the questions

where the quick coupling use

the temperature they working

the pressure they working

the burst pressure 

the fluid material 

the seal ring material

the dimensions for other elements

please contact us for more info