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ProMinent®
Metering Pumps and
Pump Systems
METERING PUMP DEFINITION
Convey
Measure
Adjust
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ProMinent®
• Convey (like any pump)
• Measure (repeated displacement of defined volume)
• Adjust
– Volume per displacement
– Frequency of displacements
METERING PHILOSOPHY
• Think of the pump as a continuous fluid measurement
device
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ProMinent®
• Converts batch processes (fluid measured, then mixed),
to in-line processes (fluids continuously measured and
mixed)
What is a Metering Pump?
Hydraulic Institute Definition:
Some Pump Manufacturers Add:
“It includes a mechanism for varying the effective
frequency of displacements.”
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ProMinent Fluid Controls
ProMinent®
“A controlled volume pump (also called a “metering”,
“proportioning” or “chemical injection pump”) is a
reciprocating power pump used to accurately displace a
predetermined volume of liquid in a specified time period
and is driven by power from an outside source applied to
the pump mechanism. It includes a mechanism for
varying the effective plunger, piston or diaphragm
displacement.”
What claims to be a Metering Pump, but isn’t?
Gear Pump
Displacement per revolution not adjustable.
Not linear from high to low RPMs due to slip
at low speed.
Air Operated
Diaphragm Pump
Displacement per stroke not adjustable. Not
repeatable due to variable air pressure,
flexible diaphragm.
Peristaltic
Pump
Displacement per revolution not adjustable.
Chemical incompatibility common w/ rotor.
Displacement per revolution not
adjustable. Tube stretch prevents
repeatability.
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ProMinent Fluid Controls
ProMinent®
Progressing
Cavity Pump
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ProMinent®
What’s all This?
Metering Pump System Hydraulics
and Application of Accessories
The metering pump system design, the fluid pumped, and
the accessories installed all play a vital role in system
safety, repeatability and reliability.
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ProMinent Fluid Controls
ProMinent®
Key Concept: Metering Pump System
Suction Head
Positive
Suction
Head
(flooded
suction)
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ProMinent Fluid Controls
ProMinent®
Negative
Suction Head
(suction lift)
Suction Lift
Atmospheric pressure always pushes down
on any fluid surface. When the pump
diaphragm creates a negative pressure in
the pump head, atmospheric pressure
forces fluid up the suction tube to fill the
cavity.
If the pump pulled a perfect vacuum, the
maximum suction lift possible on earth,
pumping water, is 34 feet.
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ProMinent Fluid Controls
ProMinent®
14.5
psia
Atmospheric pressure at 500 feet above
sea level = 14.5 psia = 1 bar = 34 feet of
water
Suction Lift
What happens if the tank
is not vented (open to
atmosphere)?
14.5
psia
14.5
psia
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ProMinent Fluid Controls
ProMinent®
14.5
psia
Specific Gravity
Sulfuric acid density = 15.34 lbs/gal
Water density
=
8.34 lbs/gal
Therefore:
S.G. = 1.84
Ammonia density
=
5.25 lbs/gal
Therefore
Water density
=
8.34 lbs/gal
S.G. = 0.63
Because atmospheric pressure forces fluid into the pump head
during the suction stroke, if the fluid has a specific gravity greater
than 1.0, the suction lift ability will be reduced.
Specific gravity is independent of viscosity, and does not impact
pump capacity, only suction lift capability.
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ProMinent®
Specific Gravity is the fluid’s density in relation to the density of
water (S.G. 1.0). For example:
Specific Gravity Impact on
Suction Lift
Actual Suction Lift =
Rated Suction Lift (water) / S.G.
Rated Suction Lift for VAMb04120
= 6.6 feet
Actual Suction Lift = 6.6 / 1.4 =
4.7’
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ProMinent Fluid Controls
ProMinent®
Application: Chromic Acid (1.4
SG)
Viscosity
Viscosity is a measure of a fluid’s resistance to flow.
Viscosities greater than that of water increase friction
loss and result in reduced pump capacity.
When selecting a pump for viscous fluids:
Oversize the pump
Put springs in the valves to help seat the balls
Reduce stroking rate to minimum possible
Keep stroke length as great as possible
Provide flooded suction with oversized suction line
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ProMinent Fluid Controls
ProMinent®
Use high viscosity solenoid pumps
Fluid
S.G.
Viscosity (SSU)
Ammonia
SAE 30 oil
Brine
Gasoline
Glycerine
Nitric Acid
Sulfuric Acid
Water
0.63
0.9
1.2
0.73
1.26
1.42
1.84
1.00
29.5
200 @ 130 deg F
33
30
2950
31.5
66
31.5
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ProMinent Fluid Controls
ProMinent®
Specific Gravity and Viscosity of Common Fluids
Vapor Pressure
Matter exist as solids, liquids or gasses. The state of matter
depends on the compound itself, the pressure around it, and the
temperature.
The Vapor Pressure of any fluid relates to the pressure and
temperature at which it flashes from a liquid phase to a gas phase.
It is defined as the pressure exerted when a liquid is in equilibrium
with its own vapor.
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ProMinent®
The higher the vapor pressure, the more likely the fluid will
vaporize on the suction side of a pump during the suction stroke,
causing cavitation.
Pressure Relief Valve
Prevents over-pressurizing pump and piping system.
Pressure Adjusting Nut
Spring
Diaphragm Hub
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ProMinent®
Diaphragm
Pressure Relief Options - Flooded Suction
3-port PRV
2-Port
BPV on
Tee
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ProMinent®
Pressure Relief may discharge back to
tank, but where tank is distant from pump,
relief back to suction line is common.
Pressure Relief Options - Suction Lift
Two port back-pressure valve
off of a tee on the discharge
line
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ProMinent®
Three port in-line pressure relief
valve discharges to tank through
relief port
Backpressure Valve
Provides backpressure to improve repeatability.
Prevents siphoning when suction head exceeds
discharge head.
Pressure Adjusting Nut
Spring
Diaphragm Hub
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ProMinent®
Diaphragm
Backpressure Valve
The anti-siphon (backpressure)
valve prevents the vacuum from
causing chemical to be drawn into
water line.
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ProMinent®
The injection quill can create a
venturi effect in a flowing pipe,
developing a vacuum. This can
draw chemical through the system
even if the pump is stopped.
Backpressure Valve
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ProMinent®
The backpressure valve
also prevents fluid from
simply free-flowing
through the system when
the suction port is higher
than the point of
discharge.
Backpressure Valve
When discharging into a vacuum line, use
two backpressure valves to ensure
maximum protection against siphoning.
The backpressure created by the two valves
(and the injection valve) is not additive.
Whichever valve is set at the highest
pressure will determine the system pressure
at the pump.
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ProMinent®
Regulatory agencies may require use of two
anti-siphon valves in certain applications
such as adding fluoride to drinking water.
In a reciprocating pump
system, the entire fluid column
between the pump and
injection point stops flowing at
each suction stroke and is
forced to flow at each
discharge stroke.
Overcoming inertia creates
large momentary pressure
spikes on the pump system.
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ProMinent®
Pulsation Dampener
Pulsation Dampener
AIR
A pulsation dampener
minimizes the pressure
spikes by using compressed
air to absorb the forces due
to momentum of the fluid
inertia.
The flow losses are called
acceleration/deceleration
forces.
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ProMinent®
FLUID
Pulsation Dampener
Principle of Operation: Air is compressible,
fluid is not.
Charge dampener air pressure to
90% of fluid pressure. You must
have backpressure for dampener to
be effective.
Locate dampener as close to pump
as possible, preferably as shown.
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ProMinent®
Size dampener volume to 26 times
fluid displacement per stroke, or
consult piping program.
Suction Lift vs. Flooded Suction
Suction Lift
Flooded Suction
Actual lift = Rated lift
(water)/ Specific
Gravity
Minimizes cavitation
and off-gassing
problems.
Requires foot
valve/strainer
Best for viscous fluids.
Required for selfdegassing pumps and
degassing bleed
valves.
Short suction line best.
Line should always be
sloping upwards.
Diaphragm failure can
drain tank.
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ProMinent®
Short suction line best.
Line should always be
sloping upwards.
Requires isolating
valve.
Suction Side Pulsation Dampening
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ProMinent®
Where losses in suction
line cause cavitation, a
suction side pulsation
dampener may be
required. The air side of
the dampener should be
at atmospheric pressure
(not charged).
Foot Valve
Suction Tube
Tube Fitting
Check Ball
Ball Check Seat
30 mesh screen keeps
solids out
Ceramic weight keeps
suction line straight,
ports let fluid in.
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ProMinent®
The foot valve is
used in a suction
lift application to
prevent loss of
prime when the
pump is stopped,
and to improve
repeatability by
preventing
cavitation.
Injection Valve
Injection quill puts chemical into flow for
good mixing
NPT thread to mount into pipe
Valve Spring (not used in PTFE valves) provides
backpressure, ensures ball seating.
Ball Check Seat
Tube Fitting
Discharge Tubing from Pump
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ProMinent®
Check Ball
noelt:
Calibration Column
• Provide a verification of the
flow rate of the chemical feed
pump
• Available in borosilicate
glass or PVC
• Sizes from 100 mL to 10000
mL
• Marked in gallons or milliliters
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ProMinent®
Real pic of cal
column
Multifunction Valve
• Operated by smooth-action rotary
knobs which automatically return to
their initial position when released
• Mounted directly on the liquid end of
the pump for:
Backpressure
Antisiphon
Priming
Draining the discharge line
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ProMinent®
Pressure relief
Float Switch
•
Monitors the fluid level in the chemical
tank
•
Single stage function
 Minimum level indication with
simultaneous shut down of the
pump
Two stage function
 First stage early warning
annunciation
 Second stage will shut down the
pump after an additional drop in
the fluid level
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ProMinent®
•
Flow Monitor
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ProMinent®
The metering monitor is used to
monitor the volume per pump stroke
by using a plastic encapsulated metal
float that is detected by the
adjustable proximity sensor.
Adjustable from 1-125 strokes. Plugs
into front of pump.
noelt:
Typical Accessory Installation
Ken to find
different graphic
Suction Lift
Injection Valve prevents backflow from pipe
Backpressure/Antisiphon valve provides backpressure
for repeatability, prevents siphoning
Pressure gauge allows setting valve pressures
Pulsation dampener reduces head loss, pulsation
Foot valve/strainer prevents loss of prime, plugging
by solids
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ProMinent®
Pressure relief valve protects system components
Piping Simulation
• Used for motor driven pumps only
• Shows if you need accessories
• Application will run well
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ProMinent®
• Solves problems BEFORE they happen
• Pump type
• Information from the technical data in the
catalog
• Chemical being metered
• Suction lift
• Chemical tank pressure
• Size and length of suction and discharge
lines
• Number of valves and fittings in the lines
• Back-pressure
• Discharge head
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ProMinent®
Information Necessary
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ProMinent®
Any Questions?