What Are Hydraulic Fittings?
Hydraulic fittings are essential components that connect oil tubes, hoses, and other hydraulic parts. They must ensure a secure connection, reliable sealing, compact size, low pressure loss, high flow rate, easy installation and removal, and good process performance.
Types of Hydraulic Fittings
In hydraulic systems, the connection types and construction of hydraulic fittings vary based on the application:
What are the Connection Methods for Hydraulic Fittings?
Flange Connections
Used for metal pipes with an outer diameter greater than 50mm.
Small-Diameter Connections
These can be categorized into straight, elbow, three-way, and four-way fittings based on the number of channels and the direction of flow.
What are the connect methods of the hydraulic fittings?
Hydraulic fittings are connected using different methods such as expansion, welding, and ferrule types.
Flare Type Fittings:
- Before assembly, the tubes are placed into a special tool.
- Tube sleeves and tubes are pressed against the tapered surface of the fitting body with a nut for sealing.
- The tube sleeve prevents the tube from rotating when the nut is tightened.
- These fittings are simple, reliable, easy to assemble and maintain, and are suitable for connecting thin-walled low-pressure pipes like copper and thin-walled steel pipes.
Bite Type Fittings:
- These consist of a fitting body, nut, and ferrule.
- The ferrule is a metal ring with a sharp blade and an inner rounded end.
- When the nut is tightened, the conical contact between the nut and the fitting body forms a seal, while the ferrule scrapes the pipe’s surface to ensure a tight joint.
- Bite type fittings are lightweight, compact, offer reliable sealing, are easy to work with, and are widely used in hydraulic systems with working pressures up to 32MPa, suitable for high-precision pipelines.
Welding Type Fittings:
- First, the nut is installed on the nozzle, which is then welded to the end of the oil tube.
- The nozzle and fitting body are installed when the nut is tightened.
- There are two sealing methods:
- Spherical and Conical Surface Contact: Requires loose installation but has poor sealing performance and low working pressure.
- O-Ring Seal: Suitable for high-pressure systems with pressures up to 32MPa.
- Welded fittings are simple, easy to manufacture, reliable, and do not require high precision in pipe size, though they demand high welding quality.
