| 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. |
Foolproof calibration:
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. |
Smooth flow:
Venturi draws injected fluid into the water stream smoothly,
continuously. |
Pulsing flow:
Flow starts and stops with each stroke of the pump. |
No backpressure valve needed:
All required flow devices are included with the metering
pump. |
Backpressure valve adds cost:
Injection quill backpressure valve adds to initial cost
and adds another component that needs maintenance. |
Excellent dispersion:
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. |
Poor dispersion:
Concentrated material goes directly into the main pipeline
without pre-dilution. Even centerline quills cannot change
the pulsating nature of the injection. |
Simple mechanism:
Water from the centrifugal pump drives a venturi. No gears,
diaphragms or pistons. Only one wearing part: the centrifugal
pump seal. No lubrication needed. |
Complex mechanism:
Reciprocating motion has many more moving parts. Oil fill
and/or lube points are needed. Repairs require a skilled
mechanic. |
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
injected chemicals. |
Greater safety:
Concentrated chemical is under vacuum. Leaks are less
likely, and they are less hazardous if they do occur. |
Less safety:
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. |
Excellent turn-down:
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? |
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