Abstract: In order to dry boards, the boards are guided on racks through a drier and brought into contact with drying air in two stages. In a stage A with a higher drying power, the drying air is supplied at a higher temperature and with an at least average humidity, and in the other stage B, it is supplied at an average temperature and with a low humidity. The waste heat of the outgoing air from stage A is used for preheating the drying air. This process should reduce the consumption of primary energy. For that purpose, a process is known that consists of also using the outgoing air condensation heat. This has the inconvenience, however, of requiring substantially more secondary energy, as important air mass flows are required to transfer heat because of the low condensation temperature. Primary energy should be reduced by using condensation heat without substantially increasing secondary energy requirements.

Abstract: In the method of feeding pulverized solid fuels into a fluidized bed hearth, the granular solid fuel is first delivered into a fuel distributing space where it is fluidized by means of a whirling stream of air and the fine granular components of the fluidized fuel are pneumatically fed through an array of feeding pipes into the fluidized bed formed in the combustion space of the hearth. The device for performing the method includes heat-resistant feeding pipes uniformly distributed between the combustion space and projecting into the fuel distributing space to immerse into the fuel distributing fluidized bed of fuel. The fluidizing air of stream is introduced into the distributing chamber to act both as the fuel conveying medium and as a combustion air in the combustion space.

Abstract: A thermal measurement of mass flow is obtained by passing a flowing mass through a hollow passageway, measuring the temperature of the mass at the inlet and at the outlet of said passageway and additionally measuring the heat flow released or absorbed through the walls of the passageway and then determining the mass flow by setting up the heat balance equation on the basis of the obtained data. Preferably, the data are fed into a computer to solve the resulting heat balance equation. The invention also comprises an apparatus wherein temperature sensors are arranged at both ends of a tubular passageway and wherein the heat flow meter comprises concentric wire coils of a thermic resistance material wound around the outer periphery of the tube and an interposed layer of predetermined thickness formed of a material of at most moderate heat conductivity.

Abstract: In order to dry boards, the boards are guided on racks through a drier and brought into contact with drying air in two stages. In a stage A with a higher drying power, the drying air is supplied at a higher temperature and with an at least average humidity, and in the other stage B, it is supplied at an average temperature and with a low humidity. The waste heat of the outgoing air from stage A is used for preheating the drying air. This process should reduce the consumption of primary energy. For that purpose, a process is known that consists of also using the outgoing air condensation heat. This has the inconvenience, however, of requiring substantially more secondary energy, as important air mass flows are required to transfer heat because of the low condensation temperature. Primary energy should be reduced by using condensation heat without substantially increasing secondary energy requirements.