The pocket penetrometer is specifically used to determine the penetration resistance of top layers (measuring depth 5 millimetres) and of samples in the field or in the laboratory. The measuring range is 0,5 MPa. It displays the the penetration resistance encountered immediately.
When pushing the instrument into the ground, the pin encounters a force of the ground. The spring is compressed by this force. A slip ring is taken along during this operation, which shows on the scale the maximum force that has been encountered.
The scale has been calibrated in such a way that the penetration resistance encountered can be read on it immediately.
