Portable measuring device

The invention relates to a portable measuring device for measuring the salinity, the acidity (pH) or other chemical and physical parameters on different types of surfaces such as inner and outer surfaces of tubes and surfaces of floors, walls, ceilings and such like, whereby the measuring device comprises electronic circuits, a measuring unit and a housing in which a test chamber has been formed, whereby the test chamber is provided with: 1) a first opening that can be positioned against a surface to be tested, 2) a second opening through which a fluid such as de-ionized water can be introduced into the test chamber, 3) a resilient seal for sealing the test chamber there where it is brought against the test surface area, 4) a number of sensors taken up in the test chamber that are connected to the electronic circuits and the measuring unit for indicating the value of the shemical or physical parameter to be measured of a solution contained in the test chamber, characterized in that the volume of the test chamber is variable.