Ar ch ive d – Seametrics TX100-200-SERIES v.2 User Manual

Page 4

INSTallaTION

Page 2

Fair (unacceptable if air is

present)

Fair (unacceptable if fluid

contains sediment)

Best

Immersion.

The TX100/200-Series standard sensors are

not designed for continuous underwater operation. If your
meter may experience occasional temporary immersion,
as in a flooded vault, a unit modified for immersion should
be specified (Option -40).

x Dia.

FLOW

An insertion flow sensor measures the velocity of flow at
one point in the pipe; flow rate and total can be inferred
from this one point. Accuracy is decreased by any factor
which makes the flow at the measured point unrepresenta-
tive of the entire flow stream. This includes distorted flow
patterns caused by upstream fittings too close to the sen-
sor. The worst offenders are fittings that increase the flow
on one side of the pipe, such as partially-opened gate or
butterfly valves. Fluid moving in a pipe does not flow at the
same velocity. Toward the center of the pipe, fluid moves
faster than at the wall, and the relationship between the
two changes as overall flow rate increases. This change
in the “velocity profile” can result in non-linearity, which
means that the K-factor (see page 7) that is correct for
one flow rate may be incorrect for another. Recommended
depth settings (see page 6) have been carefully chosen
to minimize this source of error, and should be followed
carefully, especially in the smaller pipe sizes.

Piping.

For best results, the TX sensor should be in-

stalled with at least ten diameters of straight pipe
upstream and five downstream. Certain extreme situations
such as partially-opened valves are particularly difficult
and may require more straight diameters upstream. See
Straight Pipe and Full Pipe recommendations on following
pages.

Positioning the Meter.

Horizontal is the preferred instal-

lation orientation, since it improves low-flow performance
slightly and avoids problems with trapped air. Bottom, top,
and vertical pipe installaations are all acceptable if required
by the piping layout.

CAUTION: These water meters are

not recommended for installation

downstream of the boiler feedwater

pump where installation fault may

expose the meter to boiler pressure

and temperature. Maximum recom-

mended temperature is 200ºF.

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