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The choice of the type of cambered bottom to be used is in most cases dictated by construction requirements, thus by design calculations according to specific standards (PED, ASME, etc…) Generally the choice falls between elliptical Dished Heads (2:1) and torispherical/decinormal Dished Heads (1:10).
Certainly, thanks to the massive amount of data that the Tommasin company uses for statistical purposes, the decinormal Dished Head is the most frequently used model. And this is not a coincidence!
The use of decinormal Dished Head, or with a diameter to radius ratio of 1:10, is very convenient of quality and cost management. Especially for atmospheric containers such as for the food industry, pharmaceuticals, water treatment and underground storage tanks, the use of decinormal dished heads has become a “must”.
Why should decinormal Dished heads be used?
Decinormal Dished heads are best used because:
- If the total size of the equipment has been specified, the use of the decinormal dished Heads will increase the capacity compared to the standard elliptical dished head.
- Since the curved surface of the 10% toroidal dished head is smoother than the 2:1 elliptical head, it is easy to install fixed plates and brackets on the head and the work efficiency is high.
- Since decinormal dished heads have a lower degree of processing than elliptical bottoms, the forming quality of the large diameter thin-walled decinormal head is good and the appearance is pleasing.
- If it has the same internal diameter and the same thickness as the bottom, the decinormal bottom is smaller than the elliptical bottom, the starting disc is smaller, which leads to a saving on material and today, given the time we are experiencing with the increase in raw material prices, is convinient.