YOKOGAWA RC400G, Руководство пользователя

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<8. Maintenance>
8-7
IM 12F4A1-01E
8.9.3 Checking the Discoloration of Sand in Sand Filters
Manganese or iron contained in sample water may cause contamination in the measuring tank of
the residual chlorine analyzer. Most of them, however, are absorbed by the sand. If the sand has
absorbed manganese or iron to such an extent that the entire sand is discolored, replace it with
new sand by following the procedure below.
l
Sand Replacement Procedure (see Figure 8.6)
(1) Close the sample water valve(s) and cleaning water valve to stop supplying sample water
and cleaning water.
RC400G-2: Sample water valve V3, cleaning water valve V4
RC400G-3: Sample water valves V3 and V4, cleaning water valve V6
(2) Remove the top cover on the sand filter and remove the sand from the sand filter by hand or
using a container. It is not necessarily to remove the sand completely.
(3) If the inner wall of the filter cylinder has been stained (turned black by manganese or umber
by iron), clean it with dilute hydrochloric acid or appropriate cleaner.
(4) Replenish the filter cylinder with new sand to scale marking <10>.
(5) Reinstall the top cover on the sand filter, open the sample water valve(s) and cleaning water
valve to start supplying sample water and cleaning water.
8.9.4 Filter Replacement
A filter is installed at the bottom of the sand filter to prevent the sand from falling off (see Figure
8.6). When the filter is clogged and the specified flow rate cannot be achieved, replace the filter
by following the procedure below.
l
Filter Replacement Procedure (see Figure 8.6)
(1) Close the sample water valve(s) and cleaning water valve to stop supplying sample water
and cleaning water.
RC400G-2: Sample water valve V3, cleaning water valve V4
RC400G-3: Sample water valves V3 and V4, cleaning water valve V6
(2) Remove the top cover on the sand filter and remove as much sand as possible from the
sand filter by hand or using a container.
(3) Loosen the 4 fixing screws at the bottom of the sand filter and remove the sand filter.
(4) Loosen the 4 set screws at the bottom of the filter cylinder and remove the filter by pulling
the part of cleaning (tap) water inlet downward. Remaining sand in the filter cylinder, if any,
falls together with the filter.
(5) Replace the filter with a new one, reinstall the part of cleaning water inlet, and fix the filter
with the set screws. Remove the remaining sand well by rinsing. Otherwise, scratches may
occur, causing leakage.
(6) Reinstall the sand filter and fix it with the fixing screws.
(7) Replenish the filter cylinder with sand to scale marking <10>.
(8) Reinstall the top cover on the sand filter, open the sample water valve(s) and cleaning water
valve to start supplying sample water and cleaning water.
14th Edition : Jul. 15, 2020