Doc. No. 06EN003291 Rev. A
2 - 3
Model ST98 Flow Meter
CHAPTER 2 - INSTALLATION
FLUID COMPONENTS, INTL
Install Insertion Flow Element
Note
:
The instrument accuracy will be reduced if the media flow is reversed from the flow direction of the flow
arrow machined on the flow element or if the flats are not parallel, within ±1° of the flow direction.
Install the flow element as specified for the process connection type used.
Compression Fitting Mounting (Insertion Mounting Only)
1.
Determine the inside diameter of the process pipe at the predetermined location. Calculate 1/2 of the inside
diameter. Add 0.50 inch (12.7 mm) to the dimension. Add the pipe wall thickness. Mark the flow element at
this length.
2.
Insert the flow element fitting into the process pipe and tighten per ANSI B16.5 torque specifications. Use
appropriate sealants as required. Measure the length of the ferrule that is above the pipe. Mark this
dimension above the first mark on the flow element.
3.
Position the flow element in the process pipe so that the last mark is above the ferrule. The flow element is
now placed at 0.50 inch (12.7 mm) past the center of the process pipe as shown in Figure 2-1.
4.
Adjust the flow element so the flats are parallel to flow ±1°, and the flow arrow is in the direction of flow.
5.
Ensure that the insertion length is correct before tightening the compression fitting. Readjustment of the
metal ferrule is not possible after tightening because the fitting crimps onto the flow element pipe. The Teflon
ferrule is readjustable.
6.
Hold the fitting body steady with a backup wrench and tighten the nut one and one-quarter turns past what is
hand tight. Now the flow element is sealed and locked into place.
Caution:
Be sure there is no pressure in the process line before the instrument is removed.
To remove the flow element, loosen the nut (Step 6) and unscrew the ferrule (Step 2).
NPT Pipe Thread Mounting (Insertion Mounting Only)
Alert:
DO NOT change the orientation of the flow element in the enclosure more than 180° as the
interconnecting RTD and heater wiring could be stressed and damaged. DO NOT apply any torque
to the flow element enclosure - only apply to NPT pipe surface itself.
Note:
When mounting the flow element to the process pipe, it is important that a lubricant/sealant is applied to
the male threads of all connections. A lubricant/sealant compatible with the process environment should
be used. All connections should be tightened firmly. To avoid leaks do not overtighten or cross-thread
connections.
The pipe thread configuration is similar to what is shown in Figure 2-1. Apply sealant compatible with the process
media to male threads. Carefully insert into process mount. Threads are right-handed. Tighten with an open-end
wrench on the hexagonal surface provided. Rotate until snug and continue to turn until flat is horizontal to
process flow.
Flanged Ferrule Mounting (Insertion Mounting Only)
1.
One of the configurations that can be ordered is a flange that has NPT threads. The flange can be screwed onto
the instrument's ferrule. If the flange is sperate from the ferrule screw on the flange and apply a lubricant/
sealant to the male threads and torque using ANSI B16.5 specifications. If the flange is already present,
proceed to the next step.
2.
Measure the U-Length of the flow element (from the flange face to the end of the flow element). Subtract
0.50 inch (12.7 mm) from the U-Length. The process' flanged mating surface for the flow element should be
high enough above the pipe for proper mounting of the flow element as follows: Measure the inside diameter