Quick couplers have many uses in chemical, manufacturing, transport, testing, and other industries, a quick connect coupler allows rapid tool replacement and provides a significant increase in productivity. For example, hydraulic testing processes. Quick couplings significantly reduce the time required to test each assembly. Realizing the increase in efficiency far outweighs the increased costs, Many industries are rapidly adopting quick couplings.
Then how to choose your hydraulic quick couplings for your applications? What are the main factors you should think about?
1. Connection Mechanism of hydraulic quick coupling
There are kinds of connection mechanisms that are designed for different conditions, and choosing an effective and safe connect mechanism is very important. Common types of connections include ball and sleeve, and push to connect, With a ball and sleeve coupling, the user simply needs to pull back the female sleeve from the male ball to connect or disconnect the coupler. Push-to-connect couplings allow you to push either end into the other to connect, while Luer fittings require the operator to twist the coupling. Cam-lock couplings come with connectors that fold down to connect the application.
The machine manufacturers will always choose quick coupling with a suitable connection mechanism, that makes the machine work safely and efficiently. The most popular connection mechanism is ball locked, push to connect. That is why ISO 7241 (both A and B) a developed by this connection Mechanism.
2. The valve option
The quick coupling are working for a hydraulic or other liquid circuits, it can help the circuit connect and disconnect to make people easy to change some parts. That the valve is important to prevent liquid leaks. There are types of valves, Ball valve, Poppet, and flat face. The ball valve that prevents the liquid leak by the ball was pushed to the connecting hole that the material deformation to prevent the liquid leak. The poppet and flat face will use a seal ring to prevent the leak.
Comparing the valve that uses seal materials, the ball valve is usually used for some high-pressure applications because the ball valve can work at a very high temperature, but the disadvantage is that the ball valve easy to be damaged by the impurities in the hydraulic oil or some other impurities. Use the seal rings, we have to pay attention to the material of the seal because they are different performance on different temperatures or different liquid materials.
3. Seal Materials
1， Nitrile (NBR) Buna-N & Low-Temp
Temperature range: Buna-N between -40°C and +135°C (intermittent up to +150°C); Low-Temp between -65°C and +120°C
Applications: Nitrile (NBR) is currently the most extensively used elastomer in the Fluid Seal Industry. Furthermore, Nitrile oil seals incorporate exquisite reluctance to hydraulic oils, water, silicone greases, petroleum-based oils and fluids, and alcohols. Nitrile presents great stability of working attributes such as high tensile strength, high abrasion resistance, and low compression set combined with low cost.
Resistant to: Water, Petroleum Oils & Fluids, Hydraulic Oils
2，Viton® (Fluoropolymer FKM)
Temperature range: between -20°C and +205°C or between -45°C and +230°C (intermittent/compound-specific)
Applications: FKM Fluorocarbon oil seals distinguish a great resistance to solvents and petroleum oils. They are, therefore, great for high-temperature installations and have present low compression set attributes. Additionally, they are adapted for use with large chemical exposure and hard vacuum applications.
Resistant to: Transmission Fluids, Gasoline, Petroleum Oils
4. Pipe Thread
Thread is the most important thing is for personal user, because quick couplings are usually used on the equipments, they need to connect to other components like fittings and hydarulic tubes, if the customer bought the wrong thread, it cannot work for his applications. Different countries use the very different thread and because of some countries will import equipment countries, in their marketing, all threads are covered.
National Pipe Thread Tapered (NPT) is a U.S. standard for tapered threads used to join pipes and fittings. ANSI/ASME standard B1.20.1 covers threads of 60-degree form with flat crests and roots in sizes from 1/16 inch to 24 inch Nominal Pipe Size [NPS]
There is also a semi-compatible variant called National Pipe Thread Tapered Fine (NPTF) also called Dryseal American National Standard Taper Pipe Thread, defined by ANSI B1.20.3, designed to provide a more leak-free seal without the use of teflon tape or other sealant compound.
British Standard Pipe (BSP) threads are used commonly in many countries outside the U.S. The most common BSP threaded fittings are tapered with pressure tight joints achieved by the threads.
The ISO metric screw threads are the most commonly used type of general-purpose screw thread worldwide.[1] They were one of the first international standards agreed when the International Organization for Standardization (ISO) was set up in 1947.
5. Pressure
The Pressure is the last one but the most important thing we need to think about for the applications. Don’t use the normal pressure quick couplings on the high pressure equipments, it is very dangerous.
usually, the normal quick coupling can work at a 3000-4500 PSI, that as the currently tech, that most of the quick couplings can work well. 10000 PSI is a important line to choose a higher requirements on the quick coupling types or designs.
