Pressure Indicator

A pressure indicator comprising a base, a deformable membrane fixed to the base in a fluid-tight manner according to a closed contour, and a body fixed to the base, delimiting a hollow volume covering the deformable membrane on the side opposite the base, while encompassing at least the closed contour, at least one inlet for a fluid, the pressure of which is to be measured in a pressure range, characterized in that the deformable membrane is such that the expansion thereof for said pressure range is sufficient to be visible to the naked eye and to allow a direct display indicative of the pressure, in that the base is drilled with at least one first hole a first end of which emerges between the deformable membrane and the base in the closed contour, in that the body is drilled with at least one second hole a first end of which emerges into said hollow volume, in that the other end of the first hole is linked to the inlet respectively to the open air, in that the other end of the second hole is linked to the open air, respectively to the inlet, so that a pressure, respectively a pressure reduction, of fluid at the inlet causes an expansion of the deformable membrane in the hollow volume delimited by the body and in that the indicator comprises at least two pressure marks each one facing an expansion position of the deformable membrane, for determining in accordance with said expansion position of the membrane at least three ranges of pressure values.