Magnetic pump isolation sleeve elliptical head
From the perspective of usage properties, isolation sleeves belong to small pressure vessels with liquid rotating inside the sleeve. Therefore, magnetic pumps can refer to the head structure of pressure vessels. There are several forms of internal pressure heads in chemical containers, including hemispherical heads, elliptical heads, disc-shaped heads, non folded spherical heads, conical heads, etc. After comparing the structures and processing techniques of various heads, and referring to the structural form of the isolation sleeve in the gap between the inner and outer magnetic steel, we recommend elliptical heads and disc-shaped heads. The elliptical head is based on the inner diameter and consists of half an elliptical object and a short cylindrical section. This short tube section can separate the stress at the boundary edge with large changes in cross-sectional curvature from the welding stress at the weld seam between the head and the cylinder, in order to improve the stress situation. Due to the shallower depth of the head surface compared to a hemispherical shape, magnetic pumps are more convenient for stamping and forming. But one size specification requires the use of a set of molded molds. The disc-shaped head, also known as the folded spherical head, is connected between the spherical shell and the short cylindrical section by an annular shell to make it smoothly transition and reduce the degree of abrupt curvature changes. However, under internal pressure, there is still significant edge stress generated at the connection point.
Compared with elliptical heads, its advantage is that it does not require many sets of molding dies, but manual forging is time-consuming and inefficient. Therefore, if manufacturing conditions permit, it is recommended to use elliptical head diagrams. For the convenience of design calculations, standard ellipses are used for the anti buckling heads mentioned below.
The formula diagram for designing the thickness of a standard elliptical head is as follows: the reverse buckle head has only one inner diameter of the cylinder and one corrosion allowance. The reverse buckle head literature proposes a design method for the reverse buckle head, as shown in the figure. The bottom of the isolation sleeve can be divided into three parts, namely,,, and, which can be considered as combinations of three heads. The design method for the reverse buckle head is not discussed in the literature. The author refers to a large number of literature on chemical machinery and proposes a thickness calculation method that combines internal and external pressure heads. Under the same design requirements, some are calculated according to the internal pressure elliptical head, while others can be calculated according to the external pressure elliptical head. The calculation results of the magnetic pump take the larger of the two to maintain uniform thickness of the whole.