Operating Instructions
OIO 23en Edition 10/2017
29
Safety instructions on repairs
Maintenance
Maintenance
Safety instructions on repairs
Required maintenance
Flowmeters are fundamentally maintenance-free. Under observance of the operating limits, see
"Technical data", page 8, no significant change in the characteristics could be established, even after
years of use in many cases. Conditions lying clearly above the nominal flow rate can, however, result
in excessive wear. In the case of liquids with higher abrasiveness (e.g. heavy oil with catalyst
residues, plastic components with fillers, etc.) strongly accelerated wear can occur in the flowmeter.
Notice:
In cases of doubt the manufacturer recommends already carrying out the first inspection of the
flowmeter after twelve weeks operation time.
Signs of progressive wear of individual flowmeter elements:
Tab. 1 Check table for required maintenance
1. Check the flowmeter visually and acoustically every four weeks.
2. Check for signs of wear as listed in the table above and eliminate the cause.
Re-calibration of the flowmeters
In order to maintain the high measuring precision of the flowmeter, the manufacturer recommends
carrying out the first re-calibration after about one year of operation. The results reveal any wear starting
on the measuring unit. The interval at which recalibration is actually required depends strongly on the
operating conditions of the device.
The manufacturer provides the factory calibration as standard. If higher requirements are placed on the
measuring instrument, an accredited calibration according to EN ISO/IEC 17025 is also possible.
The following safety instructions must be observed during all the repair work:
► All the work may only be carried out by authorized qualified personnel.
► Wear protective clothing during all the work.
► The replacement of the measuring unit consisting of screw set and rolling bearing may only be
carried out in the factory.
► The flowmeter has to be recalibrated after measuring unit or rolling bearing has been replaced.
► Observe the pick up operating instructions when replacing the pick up insert.
► Observe the corresponding operating instructions when replacing the temperature sensor
insert.
Finding
Cause
Elimination
Increased running noises
Incipient damage to bearing
Replace the bearing.
Leakage
Damage to sealing
Replace the seals or dry sleeve.
Measured values not
realistic