Abstract: A ventilation valve (1; 101) for ventilation of a space for keeping animals or plants includes an opening-defining circumferential framework (3; 103) for mounting in a wall of that space, and a movable panel (5; 105). The panel (5; 105) is movably attached to the framework (3; 103) for relative movement between a fully closed position, in which substantially no air can pass between the framework and the panel, and a fully open position, in which substantially the complete opening is available for passage of air. A profiled edge on the framework provides a non-linear relation between a passage opening and an opening position of the panel (5; 105). Also provided is a system for ventilating the space, having at least a single ventilation valve, and for periodically determining parameters of inside air in the space, and adjusting the opening position of the valve based on the parameters.

Abstract: A feeding station for farm animals (45), as in particular for pigs, provided with a first reservoir (3) for a first animal food component, a first conveyor pipe (15) connected to the first reservoir (3), with a first conveyor screw (17) extending internally of the first conveyor pipe (15), and a mouthpiece (7) for reception in the mouth of an animal (45). A first end of the first conveyor screw (17) is coupled adjacent to the first reservoir (3) to a rotatable first drive (21) and a second end of the first conveyor screw (17) ends shortly before the mouthpiece (7). The feeding station (1) is further provided with at least a second reservoir (5) for a second animal food component, a second conveyor pipe (16) connected to the second reservoir with a second conveyor screw (19) extending internally of the second conveyor pipe (16). A first end of the second conveyor screw (19) is coupled adjacent to the second reservoir (5) to a second drive (23) which is rotatable independently of the first drive (21).

Abstract: An air flow sensor and impeller flow for use in industrial, agricultural and civil applications as well as in process control, emission control and measurement. The impeller is suspended for free rotation in a tube section and has a central core and a number of impeller blades extending from the core wherein at least one blade extends from the core to the adjacent inner wall of the tube section. The flow sensor is equipped with measuring means to measure the number of revolutions of the impeller per unit of time and to register an associated calibration speed of the impeller.

Abstract: A gas-fired heater, in particular of the type having radiant bodies (6) to be heated by gas flames, in which fuel gas and combustion air are supplied under pressure to at least one burner nozzle (19, 10) in a proportion ensuring complete combustion, and further comprising an air chamber (9) in association with the or each burner (20), and the chamber having an outlet terminating in the ambient space of sufficient dimensions to offer no essential resistance to air flowing out into the ambient. A venturi (10) extends from the chamber (9) into the burner (20). A gas supply nozzle (18) is arranged coaxially in front of the throat of the venturi (19) within the chamber (9). Means (3, 7, 8) are provided for supplying air to the chamber (9) in a quantity slightly in excess of that needed for complete combustion at maximum capacity of the burner (20).