The composition of the pressure vessel and the role of the components

1. Cylinder: The main pressure space required for a pressure vessel to store materials or complete a chemical reaction. It is one of the most important pressure components of a pressure vessel. Mobile tank

The function of the cylinder is to provide the pressure-bearing space required by the process. It is one of the most important pressure-bearing components of the pressure vessel, and its inner diameter and volume often need to be determined by process calculations. Cylindrical barrels (ie cylinders) and spherical barrels are the most commonly used barrel structures in engineering.

When the diameter of the cylinder is small (generally less than 500mm), the cylinder can be made of seamless steel pipe, at this time there is no longitudinal weld on the cylinder; when the diameter is large, the steel plate can be rolled into a cylinder on the plate rolling machine or the steel plate can be used in the hydraulic press The upper press is made into two semi-cylinders, and the two are welded together with welds to form a complete cylinder. Since the direction of the weld is parallel to the longitudinal direction of the cylinder (ie, the axial direction), it is called a longitudinal weld, or a longitudinal weld for short. If the diameter of the container is not very large, there is generally only one longitudinal weld; as the diameter of the container increases, due to the limitation of the size of the steel plate, there may be two or more longitudinal welds. In addition, a container with a shorter length can be directly connected to the two ends of a cylinder to form a closed pressure space, thus forming a pressure container shell. However, when the container is long, due to the limitation of the size of the steel plate, it is necessary to first coil and weld the steel plate into several sections of cylinder (a section of the cylinder is called a cylinder section), and then consist of two or more cylinder sections. Group welding into a cylinder of the required length. The connection welds between the cylinder section and the cylinder section, and between the cylinder body and the end head, are called circumferential welds, or ring welds for short, because their direction is perpendicular to the axial direction of the cylinder.

2. Head: Effectively ensure sealing, save materials and reduce the workload of processing and manufacturing;

Manufacturing process of mobile tanks

Sealing head refers to the element used to close the end of the container to isolate the internal and external media, also known as end caps. The head of a cylindrical container is generally a revolving shell. According to the shape of the head surface, it can be divided into convex shape, cone shape, flat shape and combined shape. Convex heads refer to heads whose outer surface is convex, such as hemispherical, elliptical, dish-shaped and spherical heads without folding edges. Some gas cylinders use a combined bottom head with a convex surface inward, which can not only ensure the strength, but also meet the needs of safe use. 3. Sealing device: The reliability of the sealing device largely determines whether the pressure vessel is normal and safe. To run

4. Opening and connecting pipes: opening holes of various sizes or installing connecting pipes on the cylinder or head of the pressure vessel, as well as installing pressure gauges, liquid level gauges, safety valves, thermometers, etc., to open holes for the process Requirements and maintenance needs.

The design of pressure vessel openings and nozzles is based on a large number of theoretical and scientific experimental research work at home and abroad. In recent years, the connection between butt joints and shells has been subjected to local stresses generated by external forces and external bending moments, and most of them have adopted WRC Bulletin No. 107 method to calculate, the key equipment also uses the finite element method to calculate the stress of each part in detail. Since the opening and the pipe are the parts of the vessel with complex stress, many accidents originate in this part. 5. Support: The pressure vessel depends on The support is supported and fixed on the foundation.

6. Safety accessories: to ensure the safe use of pressure vessels and the normal progress of the process.

Pressure vessel safety accessories refer to auxiliary devices or instruments that ensure the safe operation of pressure vessels, including safety valves, bursting disc devices, pressure gauges, liquid level gauges, and temperature measuring instruments. The selection of pressure vessel safety accessories should be compatible with the medium and its working conditions, and the installation location should be convenient for inspection and maintenance.

The "Pressure Vessel Safety Technical Supervision Regulations" of the Ministry of Labor stipulates that: pressure vessel safety accessories implement a regular inspection system, safety valves are generally checked at least once a year, and rupture discs are regularly replaced according to actual usage; the calibration and maintenance of pressure gauges should comply with the state The regulations of the planning department; implement a regular maintenance system for liquid level gauges; pressure vessels that need to control the wall temperature must be equipped with temperature measuring instruments or thermometers, and they should be regularly calibrated.