Checking tool for pressure vessel shape and geometric size inspection
At the pressure vessel manufacturing site, inspectors need to inspect the shape and geometric dimensions of pressure vessels and parts in accordance with design drawings and technical requirements. The shape and geometric dimensions of pressure vessels and parts must meet the requirements of design drawings, technical conditions and current relevant standards. Therefore, the shape and geometric size inspection of pressure vessels and parts is an important part of the pressure vessel product manufacturing inspection process. The following is an introduction to the commonly used models for on-site inspection of pressure vessel manufacturing
1B type welded joint inspection template
The amount of misalignment of the B-type welded joints of the pressure vessel cylinder and the weld reinforcement can be inspected and measured with a welding inspection ruler. Due to size and structure reasons, when the welding inspection ruler cannot be used for inspection, the Type B welding joint inspection template shall be used, as shown in Figure 2-44 and Figure 2-45.
2A type welded joint inspection template
Type A welding joint inspection template is used to inspect and measure the misalignment of the cylinder body Type A welding joint, the weld height, etc. Type A welded joint inspection templates are divided into two types: outer arch model and inner arch model, as shown in Figure 2-46.
3 Circumferential edges and corners inspection template of welded joints
The edge angle E formed in the circumferential direction of the welded joint shall be inspected and measured with the chord length equal to 1/6 of the inner diameter and not less than 300mm, as shown in Figure 2-47 and Figure 2-48.
4 Head gap template
The head gap template is to use a gap template whose chord length is equivalent to the inner diameter of the head to inspect and measure the shape tolerance of the inner surface of the head, see Figure 2-49.
During inspection, the template should be perpendicular to the surface to be tested, and the O point of the center line of the head template should be aligned with the center point of the tested head to coincide. See Figure 2-50.
6.3.7 "Use a gap template with a chord length equivalent to the inner diameter of the head to check the shape tolerances of the inner surface of the head. The sample should be perpendicular to the surface to be tested during the inspection, and the welding seam is allowed to be measured. Oval, dish, etc. The shape tolerance of the inner surface of the spherical head should meet the following requirements:
a) The maximum gap between the template and the inner surface of the head: the convexity shall not be greater than 1.25%Di; the concave may not be greater than 0.625%Di.
b) The limit deviation of the linear dimension of the profile curve of the template: According to the m-level regulations in GB/T1804-2000. "
The term "gap template" is used in the standard, which means that the chord length of the gap template is "equivalent" to the inner diameter of the head to check the shape tolerance of the inner surface of the head. The key here is an understanding of "quite". We set the diameter of the gap template as D, so that D is equal to the standard inner diameter of the head minus the allowable tolerance of the inner diameter of the head, that is, D=Di-4 as the “equivalent” standard inner diameter contour line in contact with the detection surface. Check the measurement.
When the measured surface of the head is convex, if you use a gap template for inspection, you only need to directly use the template to measure (D) or subtract 40mm (d) from the measured value to get the convex gap value. But for the convexity, it will make it difficult to measure the convexity value if the template is padded or placed unstable. To this end, the template can be reduced by 40mm inward, that is, d=D-40 and draw a contour line as the measurement reference. Subtracting the measured value from 40mm is the convex value of the measured surface.
Note 1: The maximum tolerance of the inner diameter of the φ600~φ6000 head is (-4~+6) mm, so D =Di-4 is used as the gap sample diameter.
Note 2: The tolerance of the inner convexity of the head is 0.625% Di. According to Di=6000, the tolerance of the inner convexity is 37.5mm. After rounding, 40mm is selected as the template contour gap.
5Cylinder arc model
The cylinder arc template is used to check the roundness of the cylinder when the cylinder is rounded.
The cylindrical arc template generally adopts the inner template, that is, the outer diameter of the template is the same as the inner diameter of the cylinder.
6 spherical shell template
Use the spherical shell plate template to measure the curvature deviation of the spherical shell plate. When the spherical shell plate chord length is greater than or equal to 2000mm, the sample chord length shall not be less than 2000mm; when the spherical shell plate chord length is less than 2000mm, the template chord length shall not be less than that of the spherical shell plate. Chord length.
