On-off valve, particularly for insulation by-pass of exhaust gas expansion turbines of catalytic cracking plants

#The present invention relates to an on-off valve, particularly for insulation by-pass of exhaust gas expansion turbines of catalytic cracking plants.

#1. Field of the Invention

#The invention relates to the field of the interception of tubes within which a fluid flow passes, preferably a gaseous fluid, in order to insulate a portion, e.g. for allowing maintenance interventions. Particularly, the valve according to the present invention can be advantageously used to intercept conduits connecting a catalytic cracking plant and an expansion turbine system for the production of mechanical energy by the overpressure of the exhaust gas of the cracking plant.

#The present invention will be now described, for illustrative but not limitative purposes, according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein:

#FIG. 1 is a front view of an embodiment of an on-off valve according to the present invention;

#FIG. 2 is a first lateral view of the valve according to FIG. 1;

#Making first reference to FIG. 1, it is shown the substantially cylindrical, hollow valve body 1, provided with an opening 2 for the inlet of the gas, and with an opening for the outlet of the gas, two actuators 4 and 5, respectively to actuate two shutters (not shown), with four bonification conduits 6, placed outside the valve, for introducing overpressurized inert gas, preferably nitrogen, within the valve, to prevent losses through the clearance necessary to the movement of the drive shaft and to inertize the valve during the closure phase, with the same number of lubrication conduits 7 for the parts moving within the valve, with an inspection window 8 and with four gate valves 9, three of which are shown in the figure, for emptying the valve from possibly present liquids.

#Making reference to FIG. 2, it is possible to observe the offset positioning of the actuators 4 and 5, to minimize interferences between shutters during their movements, while FIG. 3 allows to see the inspection window 8, closed by a flanged disc.

#FIG. 4 puts into evidence that the bonification conduits 6 are realized in correspondence of the two sections, for each drive shaft, from which gas leakages are possible, as a consequence of the clearance necessary for the movement of the drive shaft.