DH Instruments E-DWT-H, Руководство по эксплуатации и обслуживанию

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E-DWT-H OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company Page 100
Oil operated piston gauge (deadweight tester), with the following characteristics:
•
Measurement uncertainty of ± 0.005 % of reading or better. A standard with higher
measurement uncertainty may be used but RPM4-E-DWT measurement uncertainty
may be degraded proportionally from normal specifications.
•
Able to supply the recommended sequence of pressure points in the range to be
calibrated: See Section 5.3.4 for information on the recommended calibration point
sequence.
5.3.3 Set-Up and Preparation
To set-up and prepare the RPM4-E-DWT for calibration of its Q-RPTs:
Note
THE RPM4-E-DWT SHOULD NOT BE REMOVED FROM THE E-DWT-H
BRACKET FOR CALIBRATION. THE RPM4-E-DWT SHOULD ONLY BE
REMOVED FROM THE E-DWT-H BY A QUALIFIED SERVICE CENTER.
Set the E-DWT-H on a stable surface near the calibration standard with it’s reference level
(TEST port) as close as possible to the calibration standard’s reference level. Consider the
high pressure connection that needs to be made to the TEST port on the top of the E-DWT-H
and access to the front panel display, keypad and Lo Q-RPT shut off valve.
Connect the calibration standard output to the E-DWT-H top or rear TEST port. The TEST port
connection is DH500 F (DH500 F: gland and collar type fitting for coned and left hand
threaded 1/4 in. OD tube, equivalent to AE F250C, HIP HF4, etc.). Plug the other test port.
In dual Q-RPT E-DWTs, the E-DWT-H TEST port connects to BOTH of the RPM4-E-DWT Q-
R-RPTs (see Figure 11).
W
Caution
If the RPM4-E-DWT has two Q-RPTs, take care to avoid overpressure of the
Lo Q-RPT. The E-DWT-H TEST port connects to both the Lo and the Hi
Q-RPTs. Use the Lo Q-RPT shut off valve on the E-DWT-H front panel to
isolate the Lo Q-RPT when applying pressure to the Hi Q-RPT (see Section
3.4). If the RPM4-E-DWT is removed from the E-DWT, note that the
RPM4-E-DWT has separate Lo and Hi TEST(+) ports, one for each Q-RPT.
Exposing the Lo Q-RPT to pressure greater than its maximum working
pressure may damage it beyond repair. The product warranty does not
cover Q-RPT damage due to overpressure.
5.3.4 Recommended Calibration Point Sequence
Calibration adjustments to E-DWT-H RPM4-E-DWT Q-RPTs are made by altering calibration
coefficients, PA and PM (see Section 5.3.1.1). To adjust these coefficients to optimum
values giving the best results over the Q-RPTs’ complete operating range, the specific
calibration point sequence defined in Table 16 is recommended.
All calibration pressures are gauge pressures.
Prior to running the calibration point sequence, the Q-RPT should be exercised:
a) Set full scale pressure.
b) Dwell at full scale pressure for 5 minutes.
c) Return to atmospheric pressure (vented).
d) Dwell for ten (10) minutes.
A dwell time of 60 seconds is recommended before taking data at each pressure increment.