Yokogawa FS20 Fittings for pH and ORP - Manual (Page 19)

IM 12B6K1-01E-E
17
5. MAINTENANCE
5-1 General
Before the electrodes can be serviced, the electrode holder should be physically separated
from the process. The fittings can be changed from the measuring position in the
maintenance position by following the reversed procedures described in §4.
5-2. Cleaning
Cleaning the fitting
When process liquid contains slurry which intends to settle in the fitting regularly, the
electrode holder must be removed for cleaning.
Cleaning the electrodes
When the sensitivity of the electrode has decreased or the response has slowed down,
the electrode should be cleaned. The 3- and 4-hole fittings are provided with a calibration
ring with a set of beakers. The electrode holder complete with electrodes and liquid earth
sensor can be placed on the ring for cleaning.
If cleaning with hot water is not sufficient, more aggressive water based agents should be
used.
- Deposits of limes, hydroxides or carbonates can be removed by immersing the electrode
in a solution containing diluted hydrochloric acid. Afterwards rinse the electrode with
water.
- Deposits of oil and fat can be removed with hot water in conjunction with a detergent.
When the results are unsatisfactory a mild (carbonate based) abrasive can be used.
- Protein (albuminous) deposits should be removed with a protein enzymatic solution. For
instance a solution containing 8.5 ml concentrated hydrochloric acid and 10 gr pepsin in
1 litre water.
Connection : nylon
Weight : approx. 300 g.
Mounting : wall mounting (support with hole for screw M5)
Temperature/
pressure ratio : max. 200 kPa (2 bar) at 100°C
Notes:
1. The dimensions of the flow tube equal to those of standard electrodes
2. The standard reference electrodes can be mounted in the container
3. To observe the electrolyte level, the container is made of PVC.
For mounting instructions see fig. 4-9
PARTS AND ACCESSORIES
ORDER NR. DESCRIPTION
K1500BW Flow tube with ceramic diaphragm
K1500EE
Flow tube with PTFE diaphragm
K1500EF Flow tube with sleeve diaphragm
K1520VA Electrolyte 3.3M KCl (250 ml)
K1520VN Thickened electrolyte 3.3M KCl (250 ml)
K1500GF Electrolyte 1M KCl (250 ml)
K1500GG Thickened electrolyte 1M KCl (250 ml)