|CSI pumped venturi metering pumps
||Most piston and diaphragm metering pumps
|Simple flow rate adjustment:
No need to stop the metering pump. Adjust the metering
valve and immediately see the effect of the adjustment
on the built-in flowmeter.
|Complex flow rate adjustment:
Stop the metering pump. Change stroke length. Calibrate.
Repeat the procedure until you get it right.
Built-in flowmeter provides continuous flow rate information.
|Tiresome calibration procedure:
The only way to check flow rate is by timing the emptying
of a calibrated cylinder with a stopwatch.
|Excellent accuracy and repeatability:
Pumped venturi injects at constant rate over its whole
operating pressure range.
|Flow varies with line pressure:
Flow rate fluctuates when pipeline pressure changes, due
to diaphragm flexing and/or ball-check seating.
Venturi draws injected fluid into the water stream smoothly,
Flow starts and stops with each stroke of the pump.
|No backpressure valve needed:
All required flow devices are included with the metering
|Backpressure valve adds cost:
Injection quill backpressure valve adds to initial cost
and adds another component that needs maintenance.
Injected materials go through 2 stages of smooth dispersion,
the first stage at the venturi and the second stage when
the liquid enters the main pipeline.
Concentrated material goes directly into the main pipeline
without pre-dilution. Even centerline quills cannot change
the pulsating nature of the injection.
Water from the centrifugal pump drives a venturi. No gears,
diaphragms or pistons. Only one wearing part: the centrifugal
pump seal. No lubrication needed.
Reciprocating motion has many more moving parts. Oil fill
and/or lube points are needed. Repairs require a skilled
|No contact between pump and the injected chemicals:
Injected liquid enters the water stream at the venturi
-- DOWNSTREAM of all moving parts.
|Whole pump is in contact with injected chemicals:
All wetted pump components are in continuous contact with
Concentrated chemical is under vacuum. Leaks are less
likely, and they are less hazardous if they do occur.
Concentrated chemical is under high pressure between the
pump and the pipeline. It can spray out from any leak.
|Wide capacity range:
Single venturi metering pump models allow injection rates
from 1 gph to 400 gph. Special designs are available for
even higher flows.
|Narrower capacity range:
Most piston pumps are limited to flows of 200 gph or less.
CSI offers configurations where minimum repeatable flow
can be less than 1% of maximum flow.
|Delivery problems at low flow:
Accuracy/repeatability of most piston and diaphragm pumps
deteriorates badly at flow less than 10% of capacity.
|Injecting multiple chemicals is easy:
Several venturis can be installed in parallel on one centrifugal
pump. CSI models are available for smooth simultaneous
injection of 1, 2, 3 or 4 chemicals.
|Injecting multiple chemicals is difficult:
Some suppliers offer dual head pumps, but these suffer
all the same disadvantages as their single-head pumps.
|More power options:
In addition to providing metering pumps for any country's
electrical characteristics, CSI offers gasoline, diesel
and hydraulic powered versions of most metering pump models.
|Few power options:
Only a few piston and diaphragm pump manufacturers offer
anything other than electric motors.
|Do it your way:
CSI offers you more capacity choices, more simultaneous
metering choices, more power choices and more system capabilities
than any other metering pump supplier.
|Why do it their way?