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Common drawing errors in pressure vessel reviews (reactor vessels): 1. Incorrect classification of the pressure vessel, mainly due to failure to follow the principles for classifying multi-chamber vessels. For example: there is a reactor that meets the monitoring requirements, with a maximum operating pressure of 0.052 MPa (400 mmHg) for its inner cylinder, a maximum operating temperature of 120°C, and a medium that is flammable, explosive, and of moderate hazard. Jacket: Maximum operating pressure of 0.6 MPa (gauge pressure), maximum operating temperature of 165°C; medium: saturated water vapor. Determine the container category: Category 1. The inner cylinder does not actually fall into any category; it only needs to be classified based on the jacket. 2. Errors resulting from incorrect category classification lead to a series of other errors, such as mistakes in the proportion of non-destructive testing and the coefficients for welded joints. 3. The technical specifications table is missing information regarding the material of the main stressed components, as well as data such as the loading coefficient and operating volume. 4. The inner cylinder is welded to the jacket; for welds between different metals (such as carbon steel and stainless steel), high-chromium-nickel electrodes are not used, only ordinary stainless steel electrodes such as A102 are employed. II. Acidic electrodes and acidic fluxes should not be used for pressure vessels of type 2 and 3. 5. The forging grade specified in the technical requirements is incorrect; Grade I forgings are used. 6. When conducting a hydrostatic test on a vertical reactor, if it is indicated as a horizontal test, it should actually be a vertical test. 7. During the hydrostatic test, since the inner cylinder is made of stainless steel, the technical requirements do not specify that the chloride ion concentration in the water should be kept at no more than 25 mg/l. 8. The requirements regarding the trial operation of mixing in the technical specifications were not followed in accordance with HG/T20569-1994. 9. During the hydrostatic test, the data on the leakage at the shaft seal is incorrect. 10. The medium inside the inner cylinder is flammable and explosive; a packing seal is used for shaft sealing, and no mechanical seal is employed. 11. The nominal pressure class of the equipment flange is incorrect, and the type of sealing surface is wrong. 12. The fasteners for the equipment flanges were selected incorrectly. (Bolts, nuts, washers) 13. The nominal pressure class of the pipe flange is incorrect, and the type of sealing surface is also incorrect. 14. The fasteners for the pipe flange were selected incorrectly. (Bolts, nuts, gaskets) 15. The technical requirements lack specifications for non-destructive testing of the weld C-seam between the equipment flange and the inner cylinder. 16. The non-destructive testing method specified in the technical requirements for the C-seam weld between the equipment flange and the inner cylinder is incorrect; for austenitic welds, MT should be used instead of PT. 17. The medium is flammable and explosive, and the requirements for static grounding of explosion-proof motors and equipment are not specified. 18. The upper end of the jacket is missing an exhaust port with a diameter of not less than 10 mm. 19. The nozzle orientation diagram lacks positioning dimensions or positioning angles. 20. The welding joint diagram of the jacket and inner cylinder is incomplete, and the bend radius is too small. 21. Diagrams of non-radial welding joints are missing. 22. The chamfer length in the diagram of the unequal-thickness butt weld joint is insufficient; for CS and LAN, the ratio is 1:3 ； The SS is 1:4 or 1:5. 23. The length of the thermometer probe is too short; it cannot be inserted below the liquid surface. 24. The pressure testing steps for hydrostatic tests and airtightness tests are incorrect. 25. The cantilever shaft shall indicate the distance from the shaft end to the bottom head. 26. The ear mounts for the vertical reactor with insulation layer selected type A, rather than type B. 27. No anti-backflow valve is installed at the steam inlet of the jacket. 28. The structure of the guide plate is unreasonable, resulting in manufacturing difficulties. 29. The bottom nozzle is poorly designed, with an excessively small opening. 30. The technical requirements do not specify that the stainless steel plates should be delivered as plates intended for use in pressure vessels. 31. The position of the sight glass on the pipe outlet layout is incorrect; it should be offset by an angle and not lie on a straight line. 32. There are too many pipe openings distributed on the same circle, resulting in excessive strength reduction. 33. The structure of the single-shaft reactor is unreasonable, as it lacks manholes. Common drawing errors in pressure vessel reviews (heat exchangers): 1. The category of the pressure vessel is incorrect; in particular, when the design pressure for a vessel with one chamber is already 1.6 MPa, it should be classified as Category II instead of Category I. 2. When the tube sheet itself has shoulders for butt jointing with the cylinder (or head), forgings are not used; instead, sheet metal is employed. 3. The grade of the tube sheet is incorrect when it is made of forgings. 4. Reverse the inlet and outlet temperatures of the tube side and shell side. 5. The pressure for the hydrostatic test was incorrect; the tube side and shell side were swapped. 6. No vent or drain port is provided in the structure. 7. If the F-type or S-type components are placed in the wrong position, they should be adjusted; also, pay attention to whether the oblong holes are of the type that expands due to heat or contracts due to cold. 8. The mounting dimensions of the saddle are incorrect; GB151-1999P87 was not followed. 9. For welded tube boxes with partition plates in CS and LAN systems, no heat treatment requirements are specified, and the sealing surfaces should be machined after heat treatment. 10. The nominal pressure class of the equipment flange is incorrect, the fasteners chosen are inappropriate, and the type of sealing surface is wrong. 11. The nominal pressure class of the pipe flange is incorrect, the type of sealing surface is inappropriate, and the fasteners chosen are not suitable. 12. The direction of the baffle notch is incorrect. 13. The spacing between baffle plates is incorrect; it is too large and does not meet the requirements for the maximum unsupported span. 14. There are non-radial nozzles on the drawings, but no diagrams of non-radial welding joints. 15. At the fixed end of the tube sheet, a shock plate is not welded to the pipe end far from the cylinder, making cylinder assembly difficult. 16. The inlet and outlet on the diagram do not match those indicated on the pipe ends, and the medium does not flow in the reverse direction. 17. No requirements for non-destructive testing are specified for the C-seam formed by welding type A or type B flanges to the cylinder. 18. When type B flanges are used, no flange stub is provided. 19. The welding of the short flange section of type B to the cylinder, where the thicknesses are different, was not carried out with edge trimming in accordance with the requirements of JB/T4700—2000. 20. When long-neck butt weld flanges are used, the welding of flanges to cylinders with unequal thicknesses is not carried out in accordance with the requirements of JB/T4700—2000. 21. For long-neck butt-welded flanges, it should be noted that when the operating pressure is greater than or equal to 0.8 times the maximum allowable operating pressure specified in the standards, the butt weld between the flange and the cylinder must undergo 100% RT or UT testing, with the acceptable grades being RT II and UT I. 22. During the hydrostatic test of stainless steel heat exchangers, the technical specifications do not specify requirements regarding water quality; it is sufficient to keep the chloride ion content in the water at no more than 25 mg/l. 23. The wrong welding material was used for flanges with gaskets (welding between stainless steel and carbon steel, low-alloy steel), high-chromium-nickel electrodes were not employed. 24. Some data may be missing in the technical data section, such as the tube bank level. And the level might be wrong. 25. Some contents are missing in the technical requirements, such as material standards, especially those related to the heat exchange tubes. 26. When the test pressure on the tube side is higher than that on the shell side, joint pressure testing is not specified in the drawings. 27. For equipment flanges, attention should be paid to the issue of bolt mid-span; this may not be indicated in the drawings. 28. The cylinder thickness does not meet the minimum thickness specified for the heat exchanger. 29. The thickness of the partition plates does not meet the minimum thickness requirement. 30. For U-tube heat exchangers, it is necessary to ensure that the bending radius of the U-tubes is at least twice the outer diameter of the heat exchange tubes, as well as to pay attention to mechanisms to prevent short circuits. 31. Heat exchangers whose tubes can be removed should be equipped with anti-loosening lugs. 32. Tubing boxes with a weight of over 30 Kg should preferably be equipped with lifting lugs. 33. In the case of vertical heat exchangers equipped with expansion joints, attention should be paid to the position of these joints relative to the ear mounts. 34. No anti-erosion device is installed at the shell-side inlet as required by standards. 35. In the welding joint diagram of the tube sheet and heat exchange tubes, when the thickness of the heat exchange tubes differs from that specified in the standards, the depth of the welding groove was not adjusted. 36. On the drawings, it is necessary to check whether the dimension markings are complete and whether the positioning dimensions of the pipe ends are complete.