Bottom element is a capacitive device, which limits the hull bottom or top (vertical units) and laterally (horizontal units), making him one. The bottoms are subject to elliptical, spherical, conical and flat. In chemistry and refining the most widely elliptical bottom. Stamped flanged (with straight fascia) are standardized elliptical bottoms and applied in the horizontal and vertical machines with an internal diameter of 0.4 to 4 m at a pressure of 0.07 MPa (0.7 atm) to 10 MPa (100 atm). When the diameter of the body is greater than 4 m are used spherical bottoms. Conical bottoms used mainly in the bottom of the vertical cylindrical apparatus independent of pressure, if required under the terms of the process (for liquid and granular media, if needed, continuous or periodic removal of a lower slope). In horizontal apparatus with a diameter greater than 1.5 m, running in bulk and low pressure (0.07 MPa) is also appropriate to apply the conical bottom with a large apex angle (140 ).
The vertex angle of 60 is applied to viscous liquids and slurries, 90 – for viscous fluids. Flat bottom, compared with spherical and elliptical are less rational in terms of strength under pressure medium, since all other things being equal, a flat bottom wall thickness is considerably greater than that of elliptical and spherical bottoms. Therefore, use flat bottom to work under pressure apparatus with a DB> 0.4 m is not recommended. However, if for some reason always need a flat end unit of pressure, in this case, you can use a flanged flat bottom, reinforced ribs.