A liquid metering pump includes an intake nozzle (2) provided with an intake valve (3) communicating with a working chamber (4) in which a piston (5) can be moved in an alternating translation movement, suction being produced, with the intake valve open, when the piston moves away from the nozzle, and delivery being produced, with the intake valve closed and liquid emerging through an outlet valve, when the piston moves towards the nozzle. The pump includes, between the intake valve (3) and the working chamber (4), a device (D) for detecting the variation in pressure, the device (D) including a duct (10), which is connected at one end to the working chamber (4) and is provided at its other end with the intake valve (3), and an element (11) which is sensitive to the pressure in the duct, the element (11) being mounted in the wall of the duct.

A pressure sensor (10) comprising: a detection film (200) which is arranged on a silicon substrate (100) and is used for detecting a pressure which is applied to the surface of the detection film and generating a bulge deformation which adapts to the size of the pressure; an optical transmitter (300) and an optical detector (400) which are arranged on the silicon substrate (100), are located on a plane which is parallel to a plane where the detection film (200) is located, and are oppositely arranged at two sides of the detection film (200); and a pressure calculation module which is connected to the optical detector (400) and is used for acquiring detected light intensity data, and calculating a pressure value according to the light intensity data.

A pressure measurement system includes a pressure pod with two chambers separated by a diaphragm such that a deformation/movement of the diaphragm is indicative of a difference between the pressures of the two chambers. Such deformation/movement is detected by a device that has no physical contact with the diaphragm, for example, by an optical detector that detects a change in the shape of the diaphragm or a movement of a protrusion on the diaphragm.