Hydraulic hose fittings are used to connect hydraulic hoses, tubes and pipes to pumps, valves, cylinders and other components of the hydraulic system. There are many types, shapes, materials, threads and sealing options for hydraulic hose couplings. Choosing the wrong coupling can reduce the efficiency of the entire hydraulic system and even pose safety problems. If you are unsure about the types of hydraulic hose fittings, you can refer to our guide to learn how to choose the most suitable fittings for your hydraulic work.
What are hydraulic fittings?
Hydraulic fittings are mechanical parts used to connect different parts of the hydraulic system (such as tubes, pipes, and hoses). They enable the fluid to flow seamlessly throughout the system, thereby achieving optimal functionality.
The fittings design comes in various shapes and sizes to withstand high pressure and temperature fluctuations. Different types of hydraulic hose fittings include elbow, straight, tee, and cross fittings, and each type of fitting has its specific application in the system.
Hydraulic Hose Assembly—Choose Hydraulic Fittings for Crimping
During the assembly process of the hose, it is necessary to decide which type of hydraulic fittings to use. The crimping fittings is the most commonly used method for assembling hydraulic hoses. How to select the appropriate fittings for assembling the hose? Before starting to assemble any hose, you need to confirm the five main issues related to the hose connector stamp (size, temperature, application, material/medium, and pressure). Once these are determined, the hose assembly technicians can start the crimping process of the hydraulic hose and fittings. Then, how to perform the crimping of the hydraulic hose and fittings? This process may vary depending on the model of the crimping machine, but usually, the technicians will mark the insertion depth on the hose, apply lubricant on the fitting rod, push it into the end of the hose, and then insert it into the crimping mold. Finally, the technicians apply pressure by starting the power device of the crimping machine to permanently fix the connector on the hose. The hose assembly technicians can help you find the best hydraulic fittings and answer any of your questions.
Material type of the hose fittings
The material used for hydraulic hose fittings determines their performance. The most common fittings are made of steel, stainless steel, brass or plastic.
Steel fittings and ss fittings are made of iron and other metals, making them more durable and improving their heat resistance.
напрыклад, carbon steel fittings made from a mixture of iron and carbon can withstand temperatures ranging from -65°F to 500°F.
Stainless steel fittings can be used in working temperature range is from -425°F to 1200°F.
They are ideal choices for high-corrosion environments. Generally, their rated pressure can reach up to 10,000 psi. Some specially designed stainless steel fittings have a rated pressure of up to 20,000 psi.
Brass fittings are less strength and durability to those of stainless steel. But they can also achieve leak-free operation and comply with SAE, ISO, DIN, DOT and JIS standards. The temperature range of brass fittings is from -65°F to 400°F. They can withstand up to 3000 psi of pressure, but it is usually recommended to use a lower pressure range.
Plastic fittings are less popular in hydraulic applications. They are generally considered more corrosion-resistant, but have lower strength and poorer durability. Therefore, although they are inexpensive, due to the higher rated pressure of metal fittings, they are more favored in the hydraulic industry.
Aluminum fittings are much lighter than steel ones and are also more corrosion-resistant. Due to their light weight, they are widely used in the automotive industry.
Types of hydraulic hose fittings
The two main types are:
Permanent Crimp Fittings (crimp fitting) - the most common type of fittings. These fitting require the use of a crimping machine to attach the hose to the fitting.
Field Attachable (pushlock fittings) - If you cannot use a crimping tool and your hose is compatible with "field attachable fitting", then they are an excellent choice.
Fitting Ends and Connector Types as below:
Hydraulic components have different types of ends and connectors, such as flange ends, pipe thread connectors, and tapered thread connectors. The choice of each type is based on the specific requirements of the hydraulic system.
Understanding these connector types is crucial for maintaining safe and efficient hydraulic operations.
Ушчыльняльнае кольца (ORFS)
The ORFS fittings adopts a high-pressure O-ring design, providing a highly leak-free service.
Because they can withstand high pressure and intense vibration conditions, they are widely used in hydraulic applications.
Examples of ORFS include:
Straight thread O-ring (STO): Known for its robust and reliable sealing mechanism, it achieves excellent sealing through the use of straight threads and O-rings. Elbow ORFS accessories, three-way ORFS accessories, and cross ORFS accessories.
BSP hydraulic fittings
These components comply with the BSP standard and are frequently used in high-pressure hydraulic systems due to their ability to provide leak-free sealing under extreme conditions.
Flange fittings
These fittings are specifically designed for high-pressure hydraulic applications and are easy to install and remove. They are particularly suitable for large-sized applications that require higher pressure. The flange fittings can distribute the bearing stress over a larger area, thereby providing a secure connection and withstanding high pressure and heavy loads.
Pipe Thread Connectors
This is the most commonly used type of hydraulic component in medium and low pressure systems. The pipe thread connector forms a tight seal through the deformation of the thread itself. They come in various types and sizes to meet the requirements of different hydraulic systems.
Tapered Thread Connectors
These connectors are similar to pipe thread connectors, but the threads are in a taper shape. The taper shape enables the threads to form a seal when tightened, and they are commonly used in medium and high-pressure hydraulic systems.
How to Choose Right Hydraulic Fittings
Sealing Type and Thread Type
If you are using NPT (National Pipe Thread) pipe thread fittings, please be extremely careful. Although using such fittings to repair leaks seems simple, just tightening the fittings is enough, this can increase the risk of the fitting breaking. Repeated replacements (loosening and re-tightening the fitting) are more likely to occur. To prevent accidental leaks, use elastic sealing rings that comply with standards such as DIN 2353, SAE J1453, etc., and switch to non-conical JIC fittings. If you use elastic sealing rings, keep the temperature conditions within the recommended range. Unfortunately, even a single overheating event can damage all the sealing rings and cause multiple leaks.
Pressure level
The hydraulic equipment usually comes with higher working pressure. To adapt with the high working pressure, more and more customers tend to use O-ring seals. They are more resistant to cracks. O-ring seals can also over-torqueing and leakage. In terms of material, the stainless steel hose fittings have the highest rated pressure.
Vibration
Vibration can affect the hydraulic hoses, potentially causing changes in torque and leading to fatigue. Please make sure to check for any leaks or damages in the areas with significant vibration.
Температура
The temperature range of the hose fitting is determined by three factors: material, coating and seal (if used). To achieve leak-free operation, if the working temperature permits, please use an O-ring seal. Please refer to the table below to understand the temperature ranges of the most common fittings and sealing materials. If you need hydraulic hoses and fittings to work under extreme temperatures, we offer special options. Contact us for more information.
Chemical compatibility and working fluid
Based on experience, the inner tube, outer cover, fittings and O-rings of the hose should be chemically compatible with each other. When choosing hoses for gas applications, extra caution should be exercised, especially in cases where there is a possibility of leakage, to avoid explosions, fires and exposure to toxic gases. It is essential to consult the manufacturer to confirm whether the hydraulic hose and fittings of the hydraulic system are chemically compatible. Additionally, pay close attention to whether the seals are compatible with the type of hydraulic oil used in the system.
Usability
Everything went smoothly until you needed to replace the parts. The delivery cycle is only a few weeks, and you need it now. Usually, most NPT and JIC parts are in ample supply and there are various configurations to choose from. Therefore, if you are using any specific parts with a long delivery cycle, please select those that are easier to find or have more stock available.
If you’re looking for reliable, hydraulic fittings that deliver precision, leak-free performance — Sinopulse is here to help. And want free samples or want to know more information about the hydraulic fitting types, please contact us.