Pressure Systems 9022 Instrukcja Użytkownika Pobierz pdf (Strona 30)

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Measurement Specialties Inc. NetScanner System (9016, 9021, & 9022) User’s Manual

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2.3.6.4 LEAK Mode Inputs

The purge/leak charge valve design includes a leak check feature capable of testing the integrity

of user pneumatic connections as well as those within the 9016 module. For the leak mode to be

used, all RUN mode pressure inputs must be dead ended (closed) by the user. When the 9016 is

commanded into the LEAK-CHARGE position, the CAL input port will be pneumatically

connected to module run side inputs. Common reference modules will connect only the

numbered run side inputs to CAL (RUN REF is not charged). True differential (reference per

port) modules will connect both the measurement input and reference port to CAL. While in the

LEAK-CHARGE position, a test pressure may be applied through the CAL port which will

charge the dead ended run side tubulation.

Once the lines are charged, the 9016 may be commanded back to the RUN position. This will

reattach the charged run side lines to their corresponding internal transducer. Consecutive

pressure readings from the 9016 will now allow user calculation of the line leak rates. Once

returned to the RUN position, lack of a pressure indicates a gross leak. A slowly declining

pressure indicates a slight leak. A leak is more difficult to detect as tubing volume increases. In

the case of true differential units where both sides of the sensor are pressurized with the leak test

pressure, an initial differential pressure of 0.0 psi should be measured when the unit is placed in

the RUN position. If the measurement or RUN side of the channel leaks at a rate greater than

the reference side, a resulting negative differential pressure will be measured. Likewise, if the

reference port tubing leaks at a rate greater than the measurement side, a resulting positive

differential pressure will be measured.

2.3.6.5 Supply Air

The 9016 models require a 80 psig minimum dry air (or inert gas) supply which is used to shift

the internal calibration valve between its different positions. Each module contains a fitting

marked “SUPPLY” for this input. Internal solenoid valves direct this supply pressure to the

proper control port on the calibration valve as required by instrument commands. The absence

of sufficient supply air to the module will prevent the calibration valve from shifting into

requested positions (i.e., RUN, CAL, PURGE, LEAK-CHARGE).

Test pressures applied to the CAL port during the leak check

operation must not exceed the full scale pressure of any internal

transducers.

WARNING! Supply air should not exceed 125 psi (875 kPa).

Excessive pressure may damage the internal solenoids.

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Pressure Systems 9022 Instrukcja Użytkownika Strona 30