Hydraulic hose fittings are key components in hydraulic systems, serving as the connection point between the hose and various fluid circuit components such as pumps, actuators and valves. The right fittings not only ensure efficient fluid transfer, but also play a vital role in maintaining system pressure and preventing leaks. Here, we will explore the different types of hydraulic hose fittings commonly used in various applications.
1. NPT Fittings: National Pipe Thread (NPT) fittings are widely used due to their ability to form a tight seal through thread engagement. These fittings are primarily used in pipelines and hydraulic systems that carry fluids under pressure. The tapered design of NPT fittings creates a leak-proof connection when properly installed.
This is a dry seal thread; a domestic tapered pipe thread for fuel delivery, which can be used for both male and female end fittings. NPTF male threads can be mated with NPTF, NPSF or NPSM female threads. NPTF pipe fittings are similar to BSPT pipe fittings but are not interchangeable, with most sizes having different thread pitches and a 60° thread angle, while BSPT threads have a 55° thread angle.
2. BSP fittings: British Standard Pipe (BSP) fittings are similar to NPT, but with different thread angles and sizes. BSP fittings are available in both parallel (BSPP) and tapered (BSPT) versions, providing flexibility for different applications. They are commonly used in hydraulic systems in the UK and Europe.
The British Standard Straight Pipe (BSP) thread, also known as the Whitworth standard thread. It can be either straight (BSPP) or tapered (BSPT), both with an inverted taper. The flanges are similar to SAE Type 61 or 62 flanges (except for -10*).
Port fittings are usually made through BSPP threads. The sealing is by a soft metal sealing ring. bspp (straight) male threads can be mated with either bspp (straight) female threads or female ports. bspp male threads fittings are straight with a 30° tapered seat. BSPP female threads are also straight with a 30° tapered seat. The female port is straight threaded with a sealing face. The seal at the port is provided by an O-ring or soft metal spacer on the male fitting.BSPP (straight thread) fittings are similar to NPSM fittings but are not interchangeable. Most sizes of threads have a different pitch, and the thread pitch angle is 55° compared to 60° for NPSM threads (-10 is a non-SAE specification for flanges).
BSPT (tapered) male threads can be mated with BSPT (tapered) female threads or BSPP (straight) female threads BSPT male threads are tapered. BSPT male threads are tapered and form a seal at the threads when mated with BSPT (tapered) female or BSPP (straight) female ports BSPT fittings are similar to, but not interchangeable with, NPTF fittings. Most of the threads have different pitches, with a 55° thread pitch angle, while the NPSM thread pitch angle is 60°.
3. JIC Fittings: Joint Industrial Committee (JIC) fittings feature a 37-degree flare for a secure, leak-proof connection. They are commonly used in high-pressure hydraulic applications and are compatible with a wide range of hose and piping systems. Their rugged design makes them ideal for harsh working environments.
37° Taper Angle (JIC) The Society of Automotive Engineers (SAE) specifies that a 37° taper angle or taper seat can be used for high pressure hydraulic lines. These fittings are commonly referred to as JIC fittings. the JIC male threads are straight threads that can only be mated with the JIC female threads, which are straight threads with a 37° taper seating surface, and the JIC female threads, which are also straight threads with a 37° taper seating surface. Their seal is formed at the 37° taper seating surface. Certain sizes of threads are identical to SAE 45° taper angle threads and the taper angle should be carefully measured to differentiate.
4. SAE Fittings: Society of Automotive Engineers (SAE) fittings are frequently used in automotive and industrial applications. These fittings come in a variety of styles, including straight, elbow, and tee configurations, allowing for flexible design options. SAE fittings typically use a flare seal, which is very effective for high-pressure situations.
SAE (45° Taper Angle) This is the term used for tube fittings with a 45° taper angle or seat. These fittings are commonly used for soft copper tubing because the material is easily machined to a 45° angle. These fittings are suitable for low-pressure applications - for example, in fuel lines and refrigeration lines. 45° SAE male threads can only be mated with 45° SAE female threads, which are straight threads with a 45° tapered seat. The SAE male thread is straight and has a 45° taper seating face, while the SAE female thread is also straight and has a 45° taper seating face. The seal is formed at the 45° taper seating surface. Some sizes of threads are identical to the SEA 37° taper angle threads. The taper angle should be carefully measured for zone rows.
O-ring end seal male threads can only be mated with O-ring end seal female threads, which are straight threads with an O-ring; female threads are straight threads with a sealing face, where the male thread seals at the O-ring and the female thread seals at the sealing
5. Metric fittings: Metric fittings are becoming more common as globalization progresses. These fittings come in a variety of thread sizes and configurations that match the specifications typically required for European equipment. Their standardization makes them easily compatible with a wide range of hydraulic components.
The French GAZ is a commonly used pipe fitting. These fittings have a metric thread with a 24° tapered seat. They are similar to German DIN fittings, but their threads differ in some dimensions. Although both are metric threads, all sizes of French fittings use fine threads, while German DIN fittings are larger and use
Coarse threads are used. Most port connections are flanged. French standard flanges differ from SAE and hellip standard flanges; they have a raised tab on the end face of the flange. This flange is called a Poclain type flange.
The German DIN (German Industrial Standard) is a commonly used pipe fitting. The so-called metric pipe couplings usually refer to DIN pipe couplings. The flanges are standard type 61 or 62 flanges (except -10). 24° DIN conical ball joints can be fitted with the three female threads shown. The male fitting is a ball-ended metric straight thread with a 24° taper seat and a ball-ended countersunk hole that mates with the O.D. of the inner tube of the fitting being used. Female threads to mate with the male thread include, for example, a 24° tapered ball-ended female thread with O-ring, metric fittings, or a general-purpose 24° or 60° tapered ball-ended female thread.
DIN 60° taper ball male fittings can only be fitted with universal 24° or 60° taper ball female fittings. The male thread is a straight metric thread with a 60° cone seat. The female thread is a metric straight thread with a universal 24° and 60° taper seat. When using a taper seat angle gauge to measure taper angles, use a 30° taper angle gauge.
6.JIS fitting: Most Japanese equipment uses fittings with a 30° taper seat and imperial standard straight pipe threads, often referred to as JIS (Japanese Industrial Standard) fittings. These fittings are not interchangeable with imperial fittings as the tapers are in opposite directions. All flanges are type 61 or 62 flanges (except -10*).
Japanese 30° taper angle male fittings can only be mated with Japanese 30° taper angle female threads. The female and male threads are straight with a 30° cone seat. The seal is formed at the 30° cone seat. The thread on Japanese 30° taper angle fittings conforms to JIS B 0202, which is the same as the BSPP thread. Both British and Japanese fittings have 30° taper seats, but they are not interchangeable as the British fittings have taper seats in the opposite direction to the Japanese fittings.
Komatsu type 30° taper angle straight thread fittings are identical to Japanese 30° taper angle straight thread fittings except for the difference in thread.
Komatsu fittings have a metric fine thread that conforms to JIS B 0207. Komatsu fittings are sealed at their 30° cone angle.
Komatsu flange couplings are similar to SAE 61 flange couplings and are completely interchangeable. The O-ring dimensions of the various flange sizes are not the same. When replacing Komatsu flanges with SAE type flanges, be sure to use SAE type o-ring.
7. Quick Disconnect Fittings: Quick disconnect fittings are ideal for applications that require frequent connection and disconnection, allowing for quick changes without the use of tools. These fittings come in a variety of designs, but typically use a ball lock mechanism to ensure a secure connection under pressure.
There are different ways of connecting pipes and pipe fittings in the hydraulic system, and the screwed-in end of the pipe adopts a connecting thread.
Taper threads are mainly used in low and medium pressure hydraulic systems by virtue of their vertebrae screwing and sealing operations using substances such as PTFE.
The sealing effect of fine thread is very good, often used in high-pressure systems, but it needs to use a combination of washers or O-rings for the end face of the closed work, and sometimes also use copper washers, which is more suitable for connecting the pipe wall is thicker in the pipeline, and its components are mainly the body of the connector, the receiver and the nut.
In use, the fitting body will be buckled to the hose, with the use of the previously mentioned gasket to seal the end face, between the fitting body and the receiver with rubber sealing, and sometimes also use the spherical sealing way to carry out.
As the pipe fitting belongs to the detachable connection element, it must meet the normal requirements of solid connection, strong sealing, reasonable size, small pressure loss, good process performance, etc. In addition, it must also meet the requirements of convenient disassembly and assembly.
Therefore, do not underestimate that a small pipe fitting, because only its existence can support the existence of the entire hydraulic system.
In summary, choosing the correct hydraulic hose fittings is critical to the efficient and safe operation of hydraulic systems. Understanding the various types available, including NPT, BSP, JIC, SAE, Metric, Jis, and Quick Disconnect fittings, will enable engineers and technicians to make informed choices that will improve system performance and life. Proper installation and maintenance of these fittings will greatly reduce the risk of leaks and system failures.