Abstract: A particulate material collecting apparatus including a cylindrical member defining therein a spiral flow chamber for forming a spiral flow of gas therein, an inlet duct and an outlet duct connected to the cylindrical member tangentially to the inner circumferential surface thereof, and a hollow inverted pyramidical member secured to the lower portion of the cylindrical member. A spiral flow guide plate having a convex surface curved radially outwardly of the cylindrical member is interposed between the cylindrical member and the inverted pyramidical member. The spiral flow guide plate is positioned so as to define two openings, one opening being located on the upstream side of the spiral flow of gas and the other opening being located on the downstream side of the spiral flow of gas.

Abstract: A heat exchanger including a separating chamber in the form of a prism having a substantially horizontal center axis and axially elongated. The separating chamber having a collecting chamber disposed beneath it has an inlet duct opening in the separating chamber and connected to one wall of the separating chamber, and an outlet duct opening in the separating chamber and connected to a wall of the separating chamber. The outlet duct may be connected to the wall to which the inlet duct is connected or to another wall parallel to the wall to which the inlet duct is connected.