Double membrane pump for use in a homogenising apparatus of a fluid product, comprising: - a pump body; - a first chamber housing the fluid product to homogenise, said first chamber being obtained in the pump body; - a second chamber housing a hydraulic fluid, said second chamber being obtained in the pump body; - a first membrane and a second membrane mutually spaced in such a way as to define an intermediate chamber containing a service fluid, said intermediate chamber being obtained in the pump body, said first membrane being interposed between the first chamber and the intermediate chamber so as to separate them, said second membrane being interposed between the intermediate chamber and the second chamber so as to separate them; - a piston partially housed in the second chamber and slidably mounted therein; - a device for detecting leakages through at least one of said membranes (6, 16), characterised in that said device for detecting leakages comprises: - at least one first sensor configured to detect a physical magnitude representing a property of the fluid present in said intermediate chamber; - a control module configured to establish if the physical magnitude detected by the first sensor is associated with a first condition that is indicative of the mixing of the service fluid with the fluid product, or if said physical magnitude detected is associated with a second condition that is indicative of the mixing of the service fluid with the hydraulic fluid, or if said physical magnitude detected is associated with a third condition that is indicative of the mixing of the service fluid both with the fluid product and the hydraulic fluid. - a pump body; - a first chamber housing the fluid product to homogenise, said first chamber being obtained in the pump body; - a second chamber housing a hydraulic fluid, said second chamber being obtained in the pump body; - a first membrane and a second membrane mutually spaced in such a way as to define an intermediate chamber containing a service fluid, said intermediate chamber being obtained in the pump body, said first membrane being interposed between the first chamber and the intermediate chamber so as to separate them, said second membrane being interposed between the intermediate chamber and the second chamber so as to separate them; - a piston partially housed in the second chamber and slidably mounted therein; - a device for detecting leakages through at least one of said membranes (6, 16), characterised in that said device for detecting leakages comprises: - at least one first sensor configured to detect a physical magnitude representing a property of the fluid present in said intermediate chamber; - a control module configured to establish if the physical magnitude detected by the first sensor is associated with a first condition that is indicative of the mixing of the service fluid with the fluid product, or if said physical magnitude detected is associated with a second condition that is indicative of the mixing of the service fluid with the hydraulic fluid, or if said physical magnitude detected is associated with a third condition that is indicative of the mixing of the service fluid both with the fluid product and the hydraulic fluid.