A heat exchanger for cooling a hot gas that contains solid particles, comprising heat exchanger tubes through which the hot gas flows, with the tubes being surrounded by a casing, and with ends of the tubes being welded, via weld seams, into bores of respective tube plates disposed at the ends of the casing. The liquid filtering system has multiple tanks connected to each which contains a gas scrubbing liquid through which the gas is bubbled. The powder is uniformly dispersed into a non-magnetic material to form a mixture having a selected uniform density. The adjustable pylon including a length adjustment screw including a threaded body and a centering post. The multiple ribbons extending from the ring unfurl due to the aerodynamic forces and provide stability to the grenade flight. The second seal extends midway up the fastening strips so that the separator moves over the second seal during movement of the slider towards the end.