The invention consists of a high sensitivity non-return valve that operates without being affected by gravity and that does not require elastic elements in order to operate correctly. In order to do so, it is comprised of a main body (1) defining a control volume (8) as well as two flappers (4, 5) located inside the main body (1) to allow fluid to exit therefrom and enter therein, with said flappers (4, 5) mounted on a same axis (6) to which they are fixedly attached and supported on the ends thereof by means of respective closing lids (2) and (3) of the main body (1). The flappers (4, 5) are capable of rotating both clockwise and anticlockwise in order to set a position that allows fluid to enter the control volume (8) from an inlet (10) as well as closing an outlet (9) when the pressure in the control volume is lower than the external pressure, and another position to block fluid from entering into the control volume from the inlet (10) and allowing the fluid in the control volume to exit through the outlet (9) when the pressure in the control volume is higher than the external pressure.La invención consiste en una válvula anti-retorno de alta sensibilidad, que no se ve afectada en su funcionamiento por la gravedad, ni precisa de elementos elásticos para su correcto funcionamiento. Para ello, está constituida a partir de un cuerpo base (1) en el que se define un volumen de control (8), así como dos clapetas (4, 5) ubicadas en el interior del cuerpo base (1) para permitir la entrada y la salida del fluido, clapetas (4,5) que van montadas en un mismo eje (6) solidario a ambas clapetas y soportado en sus extremos a través de sendas tapas (2) y (3) de cierre del cuerpo base (1). Las clapetas (4, 5) pueden realizar un giro tanto en el sentido de las agujas del reloj como en el sentido contrario, adoptando una posición que permita la entrada del fluido hacia el volumen de control (8) desde una boca de entrada (10), y el cierre de la boca de salida (9) cuando la presión
