The main components of the dead weight tester are measuring system, valve units, pressure generation, adjusting mechanism for fine adjustment and set of weights.
The measuring system consists of a fine lapped piston / cylinder pair. The weight-loaded piston is pressed down by the local gravitation of the weights. The test pressure, which is generated and adjusted by either an electric pump, or an integrated metal bellows, or externally via the admission pressure connection, acts from below towards the piston surface area.
This test pressure is increased until the pneumatic force of the medium (usually air) on the piston surface area (acting from below) compensates the weight force of the piston / weight system and the equilibrium of forces is reached. During this state of equilibrium, the piston floats freely in the cylinder.
In order to simplify the handling, the weights are already standardised to the specific determined piston surface area and the local gravitation at the installation site. The set of weights is available discreetly graduated in different pressure units (bar, Pa, psi). Piston and weights are set in rotation by manual initiation and kept floating in order to minimise the influence of static friction of piston and cylinder and therefore to guarantee a sensitive discrimination threshold.
Certificates
Data sheet download