Design of half pipe jacket in cooling device of stirred reactor
What is a half pipe jacket?
The middle part of the half pipe jacket is the kettle body. The outside of the kettle is longitudinally surrounded by the half pipe, and the half pipe is filled with circulating cooling water. The cross section of the half pipe is semicircular. The kettle body and the surrounding half pipe of the enamel reactor are welded together. The material used for the half pipe is sheet metal. Then, the sheet metal passes through the array forming rollers (concave cams) arranged in front and back. The rotation of the concave convex rollers drives the sheet metal to be transported forward, and then the sheet metal is horizontally bent to form a semicircle, and then the longitudinal bending is circular.
Technology of half pipe jacket
- 1. The half coil pipe generally adopts steam, and the upper inlet and lower outlet; the jacket generally adopts chilled water, and the lower inlet and upper outlet.
- 2. The liquid inlet extends from the top to the bottom, and the nozzle needs to be equipped with an exhaust hole, with a 45 ° inclined incision facing inward.
- 3. In order to avoid the foam formed by mixing medium remaining on the upper head and corroding the head material, a wire mesh demister can be added at the upper end of the cylinder.
- 4. The baffle is added in the mixing to create vortex and make the mixing more sufficient.
- 5. The semi coil can be divided into several sections, with the inlet and outlet as close as possible.
- 6. The inlet of the half coil should not directly enter the wall of the scour vessel, but an elbow should be added along the tangent direction of the jacket.
- 7. The flow direction of steam on the outer wall of the cylinder can be in a straight line without spiral, and then in a broken line to the next circle.
Structure of half pipe jacket
- 1. The half tube of cylinder is pressed by plate, and the half tube of head is cut by pipe.
- 2. The inner groove shall be made for the welding of the half coil pipe and the cylinder, and the root shall be fusion welded. The root gap shall be 2 ~ 3mm during welding. If the outer groove welding is adopted, the inner wall of the jacket is easy to be hanged.
- 3. Water pressure test: after the overall manufacture of the equipment, the container is filled with water to maintain pressure, and the jacket is tested to observe the jacket weld and the weld on the inner wall of the container; after the jacket pressure test, the container continues to be filled with water to test pressure.
Half pipe jacket structure is widely used in all kinds of reactors. For reactors, the difficulty is the design of half pipe jacket structure. It is very important to avoid the interference between the half pipe jacket and these accessories because of the need to arrange supports, nozzles and other accessories on the equipment.
Key points in jacket design
- (1) During the design, attention should be paid to ensure the circulation cross-sectional area of the circulating medium in the half pipe jacket and its thermal conductivity or insulation performance: generally, there is the following relationship between the inner diameter of the jacket and the inner diameter of the container, which can be followed in the design: when the inner diameter of the container is less than 600mm, the inner diameter of the half pipe is the inner diameter of the container + L (L ≤ 100mm)} when the inner diameter of the container is between 600mm and 600mm When the inner diameter of the half pipe is between 1800 ram, the inner diameter of the half pipe is the inner diameter of the container + 100 mm; when the inner diameter of the container is more than 2000 ram, the inner diameter of the half pipe is the inner diameter of the container + 200 mm.
- (2) Attention should be paid to the setting of anti scour plate in the design: in order to avoid jacket steam or other media polluting the outer wall of the inlet of the vessel, it is necessary to design an anti scour plate, which is welded on the outer wall of the vessel and facing the inlet of jacket media. When there is a space distance greater than 50 mm between the container and jacket, an inlet baffle should be designed.
- (3) When designing, pay attention to the setting of vent: in order to make the jacket space full of media, it is necessary to exclude all the gases in the jacket space, which requires the design of a vent with a diameter of not less than 10 mm at the top of the jacket, and the more at the top of the jacket, the better the exhaust effect.
- (4) Do a good job of flaw detection and heat treatment: if the medium in the container is highly hazardous medium or extremely hazardous medium, do a good job of lO0% radiographic detection, and then carry out the heat treatment after welding the closure and the container; for those with heat treatment requirements, carry out the heat treatment after welding the closure and the container.
Main structure and function of SEMI pipe machine
The working process of the half pipe machine mainly includes four steps. The metal belt is placed in the belt material support device, and then enters the half pipe rolling device through the lead-in device. Finally, the rolling is completed, and the half pipe is output through the output idler. The specific explanation is as follows:
One end of the belt material support device is used to place rolled metal belt material, which can rotate around a central axis and be continuously input into the rolling device. The belt material introduction device is mainly used to adjust the direction of belt material introduction, so that the belt material can not deviate from the direction of introduction and can be introduced between the primary molding rollers.
The inner part of the half pipe rolling device includes cycloid reducer, multiple sets of transmission gears, multiple sets of rolling roller components, box and moving cam, etc., which is mainly used for half pipe forming. The concave wheel in the device is coaxial and driven by the motor together with the main gear. The motor speed is constant, and then it is driven by a plurality of guide gears. The passive gear matching with the driving gear and the concave wheel coaxial with it will also run in the same direction at the same speed, so the cam matching with the concave wheel is also driven. In this way, with the rotation of the concave cam, the half tube sandwiched between them will be transported forward at a uniform speed and bent in sequence under the action of the multi-stage roller group, and finally gradually rolled out from the metal belt to the half tube, as shown in Figure L. It is mentioned in Section 1 that the required section of the half pipe is semicircle shape, so the change from the flat plate of raw material to semicircle section is not completed at one time. It needs to be rolled and deformed step by step, and the last rolling wheel group is most likely to finish the section.
The arc radius of the cam is gradually reduced and tends to the inner diameter of the half pipe until it is equal to the inner diameter of the half pipe. Similarly, the arc radius of the concave arc is also gradually reduced, but the difference is that it tends to the outer diameter of the half pipe. When the rolling roll group is running, the gap between the concave wheel and the cam should match the thickness of the metal strip.
The limiting device is arranged on the cam to ensure that the arc length of the convex surface is equal to the circumference of the semicircular section formed by the strip during the forming and rolling of the half pipe. In addition, the limiting device can also play the role of fixing the belt material, so as to avoid the belt material moving up and down in the molding process, and its size is gradually smaller. The clearance between the concave and convex wheels is adjustable, and the movement of the cam can guide the belt conveying direction.
The outer wall of the agitated reactor body is also circular. In order to make the half pipe wrap around the outer wall of the reactor body well, it is necessary to make the inner diameter of the extruded half pipe ring equal to that of the outer wall of the reactor body. Therefore, the center position between the cam and the concave wheel of the last rolling roller group is staggered by a certain distance a, as shown in Fig. 2, the eccentric pressing is carried out, and the half pipe can have a longitudinal direction when pressing the half pipe In this way, after the rolling of the concave convex wheel group, a half tube with a certain bending radian will be formed.
In order to better match the outer wall of different reactors, it is necessary to consider that the inner diameter of the half pipe bending into an arc is adjustable, so the movable adjustable devices are installed on the concave wheel and cam of the last stage. A movable adjustable device mounted on the concave wheel is used to change a In addition, the movable adjustable device installed on the cam is used to change the gap between the concave and convex wheels, which should be adjusted with the concave wheel adjustable device. Similarly, the size of a is inversely proportional to the gap between the concave and convex wheels, and the larger a is, the smaller the gap between them is. After mastering the relationship between the two adjustable mobile devices, it can be adjusted according to the actual situation until the gap between the concave cams is just the thickness of the metal material. In Section 1, it is introduced that the half pipe on the outer wall of the kettle body should be spirally encircled, which requires two other mobile adjustment devices to adjust the two ends of the concave wheel and camshaft, so that the shaft has a certain inclination, and then after repeated adjustment to get a suitable angle, the spiral encircling half pipe can be completed.
According to the design points, the relevant parameters are designed, and then the rolling device is used for half pipe production. This method not only saves materials, but also improves the production efficiency, which is of great benefit to cost saving and company benefit. This method is suitable for promotion.
Source: China Pipe Fittings Manufacturer – Yaang Pipe Industry (www.steeljrv.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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