Verifying accuracy of in-line flowmeters in waste-water treatment facility

Using the Panametrics Portable Ultrasonic Flowmeter provides advantages

Application
Many industrial plants have on-site water treatment facilities. Different departments
or divisions at the plant send their waste water or chemical by-products to the water
treatment facility for handling, purification or filtration. The load of waste water, in
particular, is of critical importance in these times of environmental concern because
waste water is usually discharged to a local water basin.
Most facilities use in-line flowmeters to monitor the volumetric load of waste water or
chemical byproducts as they are fed to the waste treatment facility. The accuracy of
these flowmeters must be continuously verified for purposes of legal accountability.
Background
A major semiconductor manufacturer has an on-site waste treatment facility.
Each department at the plant has its own discharge line into the facility. There
are over twenty lines, all of which run through a concourse to the remote waste
treatment facility. The discharge lines range from 2 to 1 O in and are constructed
of a variety of materials ranging from PVC to stainless steel. Various permanently
installed flowmeters monitor the flow on each discharge line just before the point
where the discharge lines enter the waste treatment facility.
The volumetric flow rate of the discharge lines is monitored on a continuous basis.
The waste treatment facility bills each department at an appropriate usage rate
for the amount it discharges. This motivates each department to optimize its
processes so as to produce the least waste discharge possible.
Problem
There is a need for an easy-to-installed portable flowmeter to verify the accuracy
and function of the permanently installed flowmeters. The volumetric flow must be
recorded over time. This data can then be compared to the customer's data as
derived from a recording device or digital acquisition control system. The calibration,
accuracy and function of the in-line flowmeter can thus be verified.

How previously handed
Previously, there was no way to verify the performance of
the permanently installed flowmeters. While various types
of portable flowmeters had been considered, they were
considered undesirable because they were bulky, required
an external recording device, or were too costly.
Advantages
Using the Panametrics Portable Ultrasonic Flowmeter, the
parameters for various discharge pipes can be permanently
programmed into the flowmeter memory as site information,
thus minimizing set-up time and effort. The portable
ultrasonic flowmeter can operate for up to eight hours on
its rechargeable battery. For longer periods of continuous
testing, it can be plugged into a standard electrical outlet.
The portable ultrasonic flowmeter can log data on a
continuous basis. After the testing is complete, the log can
be uploaded to a computer using a Panametrics instrument
interface software package (supplied separately). The data
can then be plotted and compared to data generated by the
permanently installed flowmeter.
Also the portable flowmeter can be used in case of
emergency where an in-line flowmeter fails or is not in service.
Equipment
CPT-type transducers together with a universal clamping
fixture provide noninvasive operation on all kinds of pipe
materials. The following features are of particular interest in
this application:
• Portability
• Battery-powered operation
• 1 to 2% accuracy
• Data logging capability
• PC interface capability
Installation
The portable ultrasonic flowmeter is ideal for this type of
application because it is easy to install on a wide variety
of process pipes of many different materials. When
demonstrated on a 3 in PVC pipe with waste water containing
5 to 10% entrained solids, the PT868 successfully tracked a
batch dump from the process where the flow rate changed
from Oto 250 L/min. The data was then plotted using the
graphic-display mode of the PT868. When compared to
the data from the inline magnetic flowmeter, recorded by
the customer's DAC system, a perfect correlation with 1 %
accuracy was revealed.

Specifications:
• Temperature: ambient
• Flow range: 0 to 250 L/min
(typical)
• Pipe size: 2 to 10 in
• Materials: PVC, carbon steel,
stainless steel, fiber glass
• Liquids: water with 5 to 10%
maximum entrained solids,
perchloroethane, and other
chemical/process wastes