The system EDC perform the leak pressure test in three phases: T1, T2 and T3 (See the figure in the right).
T1 Filling Time
The filling phase starts after a START command and continues all the time T1: The air exits the outlet fitting to fill the part under test at the test pressure Pr regulated by the external pressure reducer. If, during filling, the test pressure exceeds the programmed value Pr above the limit% Pr max, the test ends with a negative result of max. Pressure error.
T2 Settling Time
It is necessary to wait for the pressure in the tested product to settle. At the end of T2, if the pressure inside the piece under test is within the percentages% Pr max and% Pr min set in the parameters of the test table, the pressure value is stored as a reference point for controlling the loss limit Dp over time T3; the pressure must also be greater than the loss limit Dp. If during testing the test pressure exceeds the programmed value Pr above the% Pr max limit, the test ends with the result of reject for max. pressure error. If, on the other hand, during settling, the test pressure falls below the programmed value Pr above the limit% Pr min, the test ends with the result of Error for Minimum Pressure Error. After 0.5 s from the beginning of T2, the settling pressure P1 is stored. At the end of T2, the final settling pressure P2 is stored.
T3 Measurment Time
The pressure change (delta) is measured inside the piece under test, with respect to the value memorized at the end of time T2, with a minus sign in the event of a pressure drop (loss). At the end of the time T3 the equipment memorizes the measured pressure change: the test result is Good if the pressure change does not exceed the programmed limit Dp in absolute value, without sign. Also during the time T3 the test pressure must remain within the percentages% Pr max and% Pr min as in the time T2.