- Jack bolts are used in Sulzer RTA engines
- Tie rod should always be as close as possible to the crankshaft
- Adv of bringing tie rod closer is to reduce the bending moment on transverse girder.
- If there is bending moment on transverse girder cracks would propagate ie why Sulzer has employed a jack bolt so that the bearing top cover is held in position by the jack bolts.
- In B & W main bearing top cover is in two pieces.ie bearing cover or keep in of 2 pieces.
Any opening in a pressure vessel is kept to a minimum and for a man entry an elliptical hole is lesser in size than the corresponding circular hole. More over it is prime concern to have a smoothed generous radius at the corners to eliminate stress concentration. Hence other geometrical shapes like rectangle and square are ruled out. To compensate for the loss of material in the shell due to opening, a doubler ring has to be provided around the opening. The thickness of the ring depends on the axis length along the dirrection in which the stresses are maximum and the thickness of the shell. It is important to align the minor axis along the length of the vessel, as the stress in this direction is maximum. Longitudinal stress: Pd/2t where P= pressure inside the vessel, d= diameter of the arc, t= thickness of the shell plating Circumferential stress: Pd/4t More over a considerable material and weight saving is achieved as minor is along the direction of maximum stress.