Abstract: An electrical heating unit comprising mainly an elongate open-ended conduit-pipe element for mounting in a stove, fireplace or like device for burning solid fuel and having a circulation or warm-air system which is separate from the combustion system of the stove, fireplace or like device. The conduit-pipe element is open at the ends thereof and encloses current supply cables for electrical heating elements arranged on the conduit-pipe element. The conduit-pipe element is also provided with a plurality of thermostats and is intended to be mounted in the flow path of the circulation air externally of the hearth space of the stove. Air forced into the conduit-pipe element at the bottom thereof and departing from the conduit-pipe element at the top thereof assists in cooling the current supply cables, even when a fire is lit in the hearth space of the stove or like device.

Abstract: For obtaining a noiseless or substantially noiseless process of a flow passing through a throttle or damper device, the flow is given a speed increase with increasing acceleration in the direction of flow. Further, at least a substantial part of the dynamic component of the energy state of the flow is quenched within or immediately after the device by means of a counter-directed flow having a similar dynamic component. The invention also concerns a throttle or damper device for such a noiseless or substantially noiseless process of a flow.