Maintenance; How To Operate When Dosing Sulphuric Acid - Etatron PB Serie Manual Del Usuario

4.0 - MAINTENANCE

1. Periodically check the chemical tank level so as to avoid the pump operates without liquid. This would not
damage the pump, but may damage the process plant due to lack of chemical. PB series dosing pumps are
all supplied with level control setting. The level switch is not included therefore to be ordered separately.
Level control stops pump operation once the level into the chemical is lower then the level switch,activating
a L.E.D. on the pump (PB-CC pumps also activates an acoustic alarm).
2. Check the pump operating condition at least every 6 months, pump head position, screws, bolts and seals;
check more frequently where aggressive chemicals are pumped, especially:
- pulse and power L.E.D.;
- the additive concentration in the process plant; a reduction of this concentration could be caused by the
wearing of the valves, in which case they need to be replaced (Fig. 11) or by the clogging of the filter which
then has to be cleaned as in point 3 here below.
3. The Company suggests periodically cleaning off the hydraulic parts (valves and filter). We cannot say how
often this cleaning should be done as it depends on the type of application, we also cannot suggest what
cleaning agent to use as this will depend on the additive used.
Operating suggestions when dosing sodium hypochlorite (most frequent case):
a - disconnect the pins from the mains or by means of a onnipolar switch with 3 mm minimum distance between
the contact.
b - disconnect discharge hose from process plant;
c - remove the suction hose (with filter) from the tank and dip it into clean water;
d - switch on the metering pump and let it operate with water for 5 to 10 minutes;
e - switch OFF the pump, dip the filter into a hydrochloric acid solution and wait until the acid finishes
cleaning;
f - switch ON the pump again and operate it with hydrochloric acid for 5 minutes in a closed-circuit, with
suction and discharge hose dipped into the same tank;
g - repeat the operation with water;
h - re-connect the metering pump to the process plant.

5.0 - HOW TO OPERATE WHEN DOSING SULPHURIC ACID

In this case it is essential to bear in mind the following:
1. replace PVC crystal suction hose with polyethilene discharge hose;
2. empty any residual water from the pump head beforehand.
Warning: if the water mixes with sulphuric acid it can produce a large quantity of gas with consequent over-
heating of the area causing damage to valves and pump head.
This operation can also be done with the pump disconnected from the plant by turning the pump upside-down
for 15 to 30 seconds and without connecting the hose to the nipples; if impossible, dismount and remount the
pump head (Fig. 11) using the four mounting screws.
• 35 •
Fig. 11