1.0 PRESENTATION OF THE PUMP
This type of metering pump, complete with measuring instrument, intervenes by
measuring the pH or Rx value prevailing in the plant and then keeps dosing addi-
tive until the pH or Rx value set by the operator is effectively attained. More partic-
ularly, the HD-RX and HD-PH pumps utilize an ON/OFF system to stop the dosing
as soon as the reading on the display coincides with the set point, while the HD-
PH/P performs an intervention of the logarithmic proportional type and keeps dos-
ing at the maximum injection rate until the measured pH value comes to lie within
two units of the set point. At this stage the pump gradually reduces the injection
rate and eventually comes to a complete standstill as soon as the set point is
reached.
The pH and Rx measurements are potential difference measurements that can be
affected by such factors as temperature, the pressure existing at the point of inser-
tion of the measuring probe, and the efficiency of the electrical insulation of the
plant.
1.1 DESCRIPTION
The HD/-PH/RX and HD-PH/P pumps are available in a standard version consisting
of a die-cast aluminium case protected with acid-resisting epoxy paint. Upon
request these pumps are can also be supplied in a teflonated case. Rearward pro-
tection is assured by means of an ABS plastic panel complete with gasket, while
the control panel in anodized aluminium is protected by a transparent polycarbon-
ate cover, again complete with gasket. The pumps incorporate a transformer to
feed the electronic circuit and the 48 V electromagnet that protect the equipment
against possible supply disturbances. The available pumping capacities are set out
in Chapter 2.0 “PRINCIPAL TECHNICAL DATA
” and, more precisely, Section 2.2
“Technical data table”.
2.0 PRINCIPAL TECHNICAL DATA
STANDARD POWER SUPPLY
:
230 V AC, 50-60 HZ SINGLE PHASE
A
LTERNATIVE
POWER SUPPLY (ON REQUEST):
240 V AC, 120 V AC, 24 V AC, 50-60 HZ SINGLE PHASE (ONLY PH/RX)
M
EASURING RANGE:
pH 0-14; Rx -1400 to + 1400
SET POINT (RX):
0 ÷ 1000 mV
TYPE OF ACTION:
ON/OFF (HD-PH/RX); PROPORTIONAL (HD-PH/P)
ON REQUEST:
• OUTPUT CURRENT 4-20 MA
• MANUAL STROKE ADJUSTMENT. This combined control provides accurate flow
adjustment. This system is designed with a self lock devise to ensure accuracy
with assured repeatibility (PVC pump head).
28
ENG
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