(1) Barrel
The function of the cylinder is to provide the pressure-bearing space required by the process, and it is one of the most important pressure-bearing components of the pressure vessel. Its inner diameter and volume often need to be determined by the process calculation. Cylindrical cylinder (ie cylinder) and spherical cylinder are the most commonly used cylinder structures in engineering.
When the diameter of the cylinder is small (generally less than 1000mm), the cylinder can be made of seamless steel tubes, and 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 in the hydraulic press Press up to make two half cylinders, and then weld the two together with a weld to form a complete cylinder. Since the direction of the weld is parallel to the longitudinal direction (ie, axial direction) of the cylinder, it is called a longitudinal weld, or simply a longitudinal weld.
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 short length can be directly connected to the heads at both ends of a cylinder to form a closed pressure space, thus forming a pressure vessel shell.
However, when the container is longer, due to the limitation of the size of the steel plate, it is necessary to weld the steel plate into several sections of cylinder (a section of cylinder is called a cylinder section), and then two or more cylinder sections are welded together Into a cylinder of the required length. The connection weld between the barrel section and the barrel section, and between the barrel body and the end head, because its direction is perpendicular to the axial direction of the barrel body, is called a circumferential weld, or abbreviated as a circumferential weld.
According to its structure, the cylinder can be divided into two categories: single-layer and combined.
① Single-layer barrel The wall of the barrel is composed of a whole material in the thickness direction, that is, the wall has only one layer (to prevent corrosion of the internal medium, the anti-corrosion layer on the lining is not included). According to the manufacturing method, the single-layer cylinder can be divided into single-layer coil welding type, integral forging type, forging welding type, non-welding bottle type and so on.
Among them, the single-layer coil-welded structure is the most commonly used and currently used cylinder form.It uses steel plates to be rolled into cylinders on a large plate rolling machine, and is welded by a longitudinal weld to become a cylinder section, which is then combined with the head or end method. The blue is assembled and welded into a container, and the barrel shown in Figure 1-1 is a single-layer coiled structure.
The integral forging structure is the earliest adopted cylinder form. During manufacture, the cylinder and flange can be forged as a whole or connected with threads, and there is no weld in the entire cylinder body. After the development of welding technology, segmented forging appeared, and then welded into a forged and welded cylinder.
There are two main manufacturing methods for non-welded bottle cylinders: one is made of high-quality seamless steel tubes through the hot-spin ends at both ends; the other is the steel ingots are stamped and then hot-spin ends. Generally, integral forged and forged welding cylinders are mainly used in high-pressure and ultra-high pressure vessels, while non-welded bottle cylinders are often used to manufacture non-welded large-volume bottle pressure vessels.
The material of the overall forged cylinder is dense metallographic structure and high strength, so the quality is better, especially suitable for ultra-high pressure vessels made of high strength steel with poor welding performance. However, it requires very large smelting, forging and machining equipment during manufacturing.The material consumption is large, the steel utilization rate is low (only 26%~29%), and the amount of mechanical processing is large, so it is generally only used for inner diameter ϕ300~800mm, length Small ultra-high pressure vessels not exceeding 12m, such as polyethylene reaction kettle, artificial crystal kettle, etc.
② Combined cylinder The wall of the cylinder is composed of two or more discontinuous materials in the thickness direction. According to the structure and manufacturing method, the combined cylinder can be divided into two categories: multi-layer and winding. The specific structure will be introduced in Chapter 4 of this book.
(2) Head
According to the different geometric shapes, the head can be divided into spherical, elliptical, dish-shaped, spherical crown, cone shell and flat cover, etc., of which spherical, oval, dish-shaped and spherical crown-shaped heads are also collectively called convex Heads.
When the container does not need to be opened after assembly (generally, there is no internal parts in the container or there are internal parts but no replacement or maintenance is required), the head can be directly welded with the barrel, thereby effectively ensuring the sealing, saving materials and Reduce the workload of processing and manufacturing. For the container that needs to be opened many times due to maintenance or replacement of internal parts, the connection between the head and the cylinder should be detachable. At this time, there must be a sealing device between the head and the cylinder.
(3) Sealing device There are many sealing devices on the pressure vessel, such as the detachable connection between the head and the cylinder, the detachable connection between the container takeover and the outer pipeline, and the connection of the manhole and hand hole cover. The normal and safe operation depends largely on the reliability of the sealing device.
Bolt-flange connection (flange connection for short) is the most widely used sealing device. Its function is to connect through bolts and tighten the bolts to make the sealing elements tight to ensure the seal. The flange is divided into container flange and pipeline flange according to the connected parts.
The flange used for the connection between the container head (or top cover) and the barrel, and between the two barrels is called the container flange; the flange used for pipe connection is called the pipeline flange. In high-pressure containers, the container flange used to connect the top cover to the barrel and welded to the barrel is also called the barrel end.
(4) Opening and taking up Due to process requirements and maintenance needs, holes of various sizes or installation takeovers are often opened on the cylinder or head of the pressure vessel, such as manholes, hand holes, sight glass holes, material import and export Take over and install pressure gauges, liquid level gauges, safety valves, temperature measuring instruments and other take over openings.
Hand holes and manholes are devices used to inspect, assemble, and wash the interior of the container. The inner diameter of the hand hole shall allow the operator's hand to pass freely. Therefore, the diameter of the hand hole should not be less than 150mm. Considering that the length of the human arm is about 650~700mm, the container with a diameter greater than 1000mm should not be provided with a hand hole, but a manhole should be replaced.
Common manhole shapes are round and oval. To allow operators to enter and exit freely, the diameter of the round manhole should be at least 400mm, and the size of the oval manhole is generally 350mm×450mm.
After a hole is made in the cylinder or the head, the strength of the hole is weakened, and the stress at that place is increased. The degree of this weakening increases with the increase of the diameter of the opening, so the number of openings should be minimized on the container, especially to avoid opening large holes. The holes that have been opened in the container should also be designed to reinforce the holes to ensure the required strength.
(5) Support
The pressure vessel is supported by the support and fixed on the foundation. The supports of cylindrical containers and spherical containers are different. According to different installation positions, cylindrical container supports are divided into two types: vertical container supports and horizontal container supports, of which vertical container supports have leg supports, support supports, ear supports and skirts. There are four types of support; the spherical container mostly uses column or skirt support.
(6) Safety accessories
Due to the use characteristics of pressure vessels and the chemical process characteristics of their internal media, it is often necessary to install some safety devices and measurement and control instruments on the vessels to monitor the parameters of the working medium to ensure the safe use of pressure vessels and the normal progress of the process.
The safety accessories of pressure vessels mainly include safety valves, rupture disc devices, emergency shut-off valves, safety interlock devices, pressure gauges, liquid level gauges, temperature measuring instruments, etc.
The above six major components (cylinder body, head, sealing device, opening nozzle, support and safety accessories) constitute the outer shell of a pressure vessel. For storage containers, this shell is the container itself; for containers used in chemical reaction, heat transfer, separation and other processes, the internal parts required by the process must be loaded into the shell to form a complete product.
发送反馈
历史记录
Hot Tags: stainless steel pressure vessel with ce, China stainless steel pressure vessel with ce manufacturers, suppliers, factory, Plate Heat Exchanger, Heat exchanger parts, Diaphragm Pressure Vessel, Intelligent heat exchanger unit, High Pressure Vessel, Replacement accessories