Abstract: The invention concerns a device comprising a flexible and non-elastic yarn divided by at least three retaining means fixed to predetermined locations and at least three fixing means adapted to support the retaining means and whereof the diameter of each fixing means is substantially equal to the internal diameter of the retaining means so as to position the yard along a direction perpendicular to that of the axis of the corresponding fixing means.

Abstract: An open hearth boiler includes a body intended to be positioned above an open hearth. Inflow and outflow pipes are connected to the body and to a central heating or hot water circuit. The body includes internal combustion chambers which contact the flames and combustion gases. The combustion chambers are spaced from one another and baffles between various chambers define a spiral internal circulation circuit for a heat exchange fluid in the body.