BULLETIN NO. IM142/09
Instrument
Mid-West
®
INSPECTION
Before installation check the nameplate on each
instrument against the receiving paperwork and the
intended application for correct part number, materials
of construction, working pressure, dial range, etc. If
equipped with switches, check electrical rating. Inspect
for shipping damage and, if damaged, report it
immediately.
NOTE - Before attempting repairs contact your
local Mid-West Representative or our factory.
Failure to do so will void any warranty.
PRODUCT DESCRIPTION
The Model 142 "Delta Meter"® is a medium range
differential pressure instrument available as a switch, a
gauge, or both. See the “Part Numbering System”,
(Fig. TBD) for available options.
A flexible elastomer diaphragm and calibrated range
spring are moved by differential pressure. A pair of
magnets, coupled with the diaphragm, transmit this
motion through the wall of the pressure housing to a
follower magnet attached to an indicating pointer. The
rotation of the follower magnet causes the pointer to
track the movement of the internal magnet and indicate
the differential on the dial scale.
INSTALLATION
The model 142 is calibrated and tested prior to
shipment and is ready for immediate installation. Use
of the following installation procedures should eliminate
potential damage and provide optimum trouble-free
operation.
1. PROCESS CONNECTIONS
1/4" FNPT are provided as standard however check
the paperwork for the connections ordered. There are
two connections on the housing identified as "hi" and
"lo" for high pressure and low pressure. Be sure these
get plumbed to the proper connections on your
system. Improper connection will not damage the
instrument, but it will not function properly. Flexible
tubing is recommended to minimize effect of possible
vibration.
2. INSTRUMENT LOCATION
On liquid service the instrument should be mounted
below
the process connections to facilitate self-
bleeding. On gas service it should be located
above
the process connections to promote self-draining. If
the process contains particulates, a "pigtail" loop or
drop leg (manometer "U-tube" configuration) in the
tubing will minimize the possibility of it migrating into
the instrument.
3. PANEL MOUNTING
Gauges with 2-½" dials can only be mounted through
the
rear
of the panel. Make the proper panel cutout as
indicated in (Fig .TBD). Remove the (4) bezel screws.
Insert the gauge front through the rear of the panel and
reinstall the bezel screws through the front of the panel
and into the gauge bezel. Tighten the screws securely,
alternating in a
diagonal
pattern.
Gauges with a 3 1/2 “ dial must be mounted from the
front of the panel. Contact the factory for mounting
information and dimensional data.
MODEL 142: “DELTA METER
®
”
Installation and Operating Instructions
