Abstract: Am adjustment device reusable on equipment such as sports equipment for children or as a pram, pushchair, stroller or similar device to adjust the spacing between wheels of such equipment. The adjustment device includes at least one slider body comprising a curved guide track disposed on the body of the equipment mirror-symmetrically to the longitudinal principal plane of the at each side of said longitudinal principal plane, the slider body comprises a sliding member that is configured to correspond in size and shape to the curved guide track of the slider body, and can be displaced along the curved guide track of the slider body, with the curved movement paths of the sliding members and the centrelines of the guide tracks of the slider body constituting mutually corresponding circular arcs.

Abstract: Direct current power gained by photovoltaic cells can be used for heating water in a boiler. Simple installation allows use for domestic or industrial purposes, with a minimal impact to building construction. At the time of lack of sunlight intensity, water heating is provided by gas, or other heating source, or by use of a heating coil supplied by alternating current for that heating. When sunlight intensity is high, the photovoltaic cells of the present invention can be used alone. However, the source of the direct current has to be properly dimensioned in dependence on the volume of the boiler. An output 1 kWh of the source of the direct current gained by photovoltaic cells can be used to heat water of a volume of 100 L.

Abstract: Direct current power gained by photovoltaic cells can be used for heating water in a boiler. Simple installation allows use for domestic or industrial purposes, with a minimal impact to building construction. At the time of lack of sunlight intensity, water heating is provided by gas, or other heating source, or by use of a heating coil supplied by alternating current for that heating. When sunlight intensity is high, the photovoltaic cells of the present invention can be used alone. However, the source of the direct current has to be properly dimensioned in dependence on the volume of the boiler. An output 1 kWh of the source of the direct current gained by photovoltaic cells can be used to heat water of a volume of 100 L.