Abstract: In order to construct a watering system for watering an agricultural area as economically as possible and independently of environmental conditions, it is suggested to supply both a drive for the movement of a watering unit and also a pump system with current or voltage by means of a photovoltaic unit or a plurality of photovoltaic units.

Abstract: For operating pumps above the respective system resistance for all volume flows, for a spring-loaded, directly acting overflow valve for limiting the pressure in a system in which a liquid is lifted by a positive-displacement pump and flows through the system with varying rates of flow, the valve chamber (1) and the valve body (22) with the valve head (14) placed therein are constituted in such a way that the valve head, after lifting off from the valve seat (3), has a second active diameter which is bigger than the first active diameter, whereby the valve head (11) simultaneously releases, with increasing stroke of the valve body (22), an enlarging flowing-through cross section, whereby the valve body (22) is constituted in one part as a valve piston (11) sliding in the valve chamber (1) with a third active diameter which is bigger than the second active diameter so that the liquid flowing through the valve chamber (1), the valve being opened, produces a pressure difference which acts onto the valve piston (

Abstract: In order to provide, in vane pumps, an effective compensation of the radial and axial forces while at the same time increasing their useful service life, the vane pump for liquids is comprised of a slotted rotor (1) supported in a stator (4), wherein radially displaceable vanes (9) are slidingly disposed, which can be pressed slidingly supported while acted upon by centrifugal force, spring tension or otherwise by compressive force against a stator inside wall, in said process delivery cells are formed which expand or narrow in a crescent-like fashion and the entry of the liquid takes place through a hollow concentric stator and the filling of the vane cells from the inside to the outside. The rotor (1) is shaftless and of tubular construction, both sides are extended beyond the operating area determined by the vanes and the rotor is supported with the extensions in the outer stator, while the rotor possesses continuous vane slots from the internal to the external diameter.