Flange connection

1: Flange connection is the valve with the pipeline or equipment between the most used connection form. Refers to the flange, gaskets and bolts connected to each other as a group of combined sealed structure of the detachable connection. Pipe flanges shall be used in the equipment to refer to the inlet and outlet flanges of the equipment. Flange connection easy to use, can withstand greater pressure. Flange connection can be applied to a variety of nominal size, the nominal pressure valve, but the use of temperature has a certain limit, at high temperature conditions, due to the flange connection bolts prone to creep phenomenon caused by leakage, the general situation of LAN connection recommended in the ≤350℃ temperature use.

According to the combination of surface shape can be divided into the following:

Smooth type: for valves with low pressure. Processing more Convenient

Concave-convex: High working pressure, can use medium hard washer

Tenon Groove Type: Available plastic deformation of the larger gasket, in the corrosive medium used more widely, better sealing effect

Trapezoidal Groove: A valve or high temperature valve used for working pressure ≥60kg/Square centimeter with an oval metal ring as washer

Lens type: Washer is a lens shape, made of metal. High pressure valves or high temperature valves for working pressure ≥ 100 kg/cm

O-Ring type: Newer flange connection form, the sealing effect is more reliable than normal plain washer

2: Connect to the Clamp

Use bolts to directly connect the valve and the two pipes through the clamp.

3: Welding Connection

Welding connection refers to the valve body with welded groove, through the welding method and piping system connected to a form of connection.

GB/t 12224, API600, ASME B 16.34 standards on the welding groove made provisions.

The welding connection between the valve and the pipe is divided into the butt welding connection (BW) and the Socket Welding connection (SW), and the socket welding end shall conform to the provisions of jb/t 1751. The butt Joint (BW) can be applied to various sizes, pressure and high-temperature conditions, Socket welding (SW) is generally applicable to ≤dn50 valves.

4: Thread Connection

This is a simple connection method, often used in small valves. It is divided into two different situations:

Direct seal: internal and external thread directly to the sealing function. In order to ensure that the connection is not leaking, often with lead oil, wire hemp and PTFE raw materials with fill, of which PTFE raw materials, widely used. This material has good corrosion resistance, excellent sealing effect, easy to use and save, disassembly, it can be completely removed, because it is a layer of Non-stick film, than lead oil, line hemp superior.

Indirect seal: The force of thread tightening, passed to the washer in two planes, so that the washer is sealed.

5: Card Sleeve Connection

The working principle of the card sleeve connection is that when tightening the nut, the card sleeve is under pressure to bite the edge of the pipe outside the wall, and the outside cone of the card sleeve is closed with the cone of the joint inside the pressure, so it can reliably prevent leakage.

The advantages of this form of connection are:

1 small size, light weight, simple structure, easy disassembly;

2 strong connection force, wide use, high pressure (1000 kg/square centimeter), high temperature (650 ℃) and shock vibration;

3 can choose a variety of materials, suitable for anti-corrosion;

4 processing accuracy requirements are not high;

5) Easy to install at high altitude.

6: Clamp Connection

This is a quick connection method that requires only two bolts and is suitable for low pressure valves that are often removed.

7: Inner self-tightening connection

The inner self-tightening connection is a kind of connection form which uses the pressure of the medium to tighten itself. Its seals are in the inner cone, with the opposite side of the medium into a certain angle, the medium pressure to the inner cone, and passed to the seal ring, at a certain angle of the cone, resulting in two of the force, one with the center line of the body parallel to the outside, another pressure to the body wall. The force behind this is the self tightening. The greater the pressure of the media, the greater the tension. So this type of connection is suitable for high-pressure valves. It is more than the flange connection, to save a lot of material and manpower, but also need a certain preload, so that in the valve pressure is not high, the use of reliable.

The valve, which is made by the principle of self tightness sealing, is usually high pressure valve. Valve connection is also a lot of forms, such as some do not have to remove the small valve, with the pipe welded together, some non-metallic valves, using socket connection, and so on. The valve user should be treated according to the circumstances.

8: Other

Other forms of valve connection are many, such as the need to remove the small valve, with the pipe welded together, and some non-metallic valves, the use of socket connection, and so on. The valve user should be treated according to the circumstances.