1
Instruction Manual
1.1 GENERAL
MILROYAL
®
G pumps are reciprocating, chemical
dosing pumps capable of producing controlled
flows up to 130 gallons per hour (492 L/H) at
pressures up to 600 psi (41 BAR) (depending on
the model). These pumps feature the robust High
Performance Diaphragm (HPD) liquid end, which
eliminates the need for contour plates, and a
non-lost motion stroke adjustment mechanism
based on the variable eccentric principle. This non-
lost motion design substantially reduces pressure
and flow pulsations which in turn increases the
life of system components and results in a more
continuous chemical injection. It is designed
for industrial service and offers an accuracy of
±1% of 100% rated flow between 10% and 100%
of its flow range.
The High Performance Diaphragm (HPD) liquid end
combines all of the best characteristics of traditional
liquid ends into one technologically advanced
design. Its operating characteristics and simplicity
of operation make it the best liquid end to consider
first for most metering pump applications.
Milton Roy’s HPD liquid end overcomes the
net positive suction head (NPSH) restrictions
associated with conventional disc diaphragm
metering pumps. This is accomplished by a unique
mechanically actuated refill system (MARS) that
eliminates the need for diaphragm support plates
thereby lowering pump NPSH requirements.
The MARS also does away with the need for field
adjustment of the refill mechanism by automatically
compensating for process liquid modifications.
This, combined with removable check valves,
makes the HPD an ideal choice for any process in
which downtime is critical.
The HPD features a preformed, PTFE faced
elastomer diaphragm that is compatible with a
wide range of process liquids and chemicals.
The convoluted design of this composite diaphragm
also offers extended life over conventional flat disk
designs.
The HPD liquid end is particularly suitable for
pumping costly, aggressive or hazardous liquids
without leakage.
1.2 PRINCIPLE OF OPERATION
(Refer to Figure 5 Through 10)
The pump consists of two major assemblies;
the drive and the liquid end. Pump delivery is a
function of the drive’s stroke rate (strokes/minute),
plunger size and stroke length (% Capacity).
Stroke length can be adjusted while the pump is
running or stopped by turning the stroke adjustment
knob (330).
The drive motor transmits rotary motion to a
worm gear speed reduction unit (343, 50) which
in turn drives the variable eccentric crank (100).
The adjustable crank imparts reciprocating
motion to the plunger/connecting rod assembly
(60, 520, 525). The stroke length is adjusted by
changing the position of the variable eccentric
crank in the connecting rod assembly.
SECTION 1 - DESCRIPTION
