The basic structure of pressure vessel
Pressure vessels mainly have three forms: cylindrical, spherical, and rectangular. Among them, rectangular vessels are mostly used as small atmospheric storage tanks due to their poor pressure-bearing capacity; spherical vessels, due to manufacturing reasons, are usually used as large and medium-sized storage tanks with a certain pressure; while the round and simple vessels are easy to manufacture and install. The internal parts are convenient, and the pressure-bearing capacity is good, so it is the most widely used in industry.
Thin-walled cylindrical pressure vessels are usually formed by coil welding of steel plates. It is generally composed of simplified characters, heads, supports, flanges, sealing devices, safety accessories, instruments, manholes, process takeovers, etc., as shown in Figures 1-5.
- Cylinder and head
The cylinder and the head are the main pressure components that constitute the container space. According to the different geometric shapes, the simplified form can be divided into cylindrical, conical, spherical, elliptical, rectangular, etc. The head can be divided into the flat cap, dish, hemispherical, spherical crown, elliptical, and cone. Shaped seal first and so on.
Support is a component used to support and fix equipment. According to the different structural forms of pressure vessels, three common types are vertical vessel support, horizontal vessel support, and spherical vessel support. The vertical container supports include: leg supports, support supports, ear supports, and skirt supports; horizontal container supports include: support, saddle, and ring supports, of which saddle The bearing has the most applications. The spherical container mostly adopts column or skirt support. The selection of the support form is mainly based on the quality, structure, load-bearing, operation and maintenance requirements of the vessel.
- Safety accessories and instruments
To ensure the container’s safe, stable, and reliable operation, it is often necessary to install some safety accessories and instruments on the container. Pressure vessel safety accessories include safety valves, bursting disc devices, emergency shut-off devices, safety interlocking devices, etc.; instruments include pressure gauges, liquid level gauges, thermometers, etc.
- Opening and taking over
In the pressure vessel, due to the process requirements and the need for maintenance and testing, installation holes of various sizes and process pipes are often opened on the cylinder or head, such as manholes (or hand holes), sight glass holes, and material inlet and outlet pipes. The installation of pressure gauges, safety valves, liquid level gauges, etc.
- Sealing device
There are many sealing devices on the pressure vessel, such as the detachable connection between the cylinder and the head, the connection between the container nozzle and the outer pipe, the manhole, and the hand hole, etc. The sealing device avoids the leakage of the medium to ensure the normal, safe and reliable operation of the pressure vessel, and the flange sealing structure is often used at the connection.
1—Saddle support; 2——one head; 3——one head splicing girth welds; 4——one reinforcing ring; 5——a manhole; 6——a longitudinal splicing welding seam of the cylinder; 7—Cylinder body; 8 ——a connecting flange; 9——a pressure gauge; 10——a safety valve; 11——a level gauge