The pipe joint is a detachable connection between the oil pipe and the oil pipe, and the oil pipe and the hydraulic component. It should meet the requirements of convenient assembly and disassembly, reliable connection, reliable sealing, small size, large oil flow capacity, small pressure loss, and good processing technology. And so on.
1), the classification standard of pipe joints
1. According to the connection method of the oil pipe and the pipe joint, the pipe joint mainly has the welding type, the sleeve type, the flaring type, and the crimping type.
2. According to each type of pipe joint, there are straight-through joints, right-angle joints, three-way joints, etc. according to the number and direction of the joints.
3. According to the connection with the machine body, it can be divided into thread connection and flange connection. In addition, there are some pipe joints for special purposes.
2) Selection standards for hydraulic pipe joints
1. Card sleeve type pipe joint
This type of pipe joint mainly includes three components of a compression nut with a connector body 4 with a 24° tapered hole and a ferrule 2 with a sharp inner edge for compression. When the nut is tightened, the ferrule is pushed into the 24° taper hole and deformed to make the ferrule form a spherical contact seal with the conical surface of the joint body. At the same time, the inner cutting edge of the ferrule is inserted into the outer wall of the tubing l and an annular shape is pressed out on the outer wall. Groove, so as to play a reliable sealing role. The bite-type pipe joint has the advantages of simple structure, good performance, light weight, small size, convenient use, no welding, less stringent requirements on the axial size of the steel pipe, and good vibration resistance. The working pressure can reach 31.5MPa, which is ideal in hydraulic systems. The pipeline connection piece.
2. Flared pipe joints
This type of pipe joint has two structural forms: A type and B type. It is composed of a joint body l with a 90° outer cone and a nut with a 90° inner cone hole. Place the pipe that has been punched into the bell mouth between the outer cone of the joint body and the inner cone hole of the pipe sleeve (or B-nut), and tighten the nut so that the bell mouth of the pipe is pressed against the outer cone of the joint and The gap created by the taper hole in the pipe sleeve (or B-type nut) plays a role of sealing. The ferrule joint has simple structure, good performance, convenient processing and use. It is suitable for medium and low pressure pipeline systems with oil and gas as the medium. The working pressure depends on the allowable pressure of the pipe material and is generally 3.5MPa-16MPa.
