Pilgrim Pressure Gauges Process - Manual (Page 8)

Product Selection Information
Ashcroft
®
Duragauge
®
Pressure Gauge
Rear Cover
Gasket
1279 Case used for illustration purposes
Screws
Bourdon Tube System
Phenol Case
Dial
Micrometer Pointer
Threaded Ring
Window
Gasket
Consult ASME B40.1 for guidance in
gauge selection
WARNING: To prevent misapplication,
pressure gauges should be selected
considering media and ambient operat-
ing conditions. Improper application can
be detrimental to the gauge, causing
failure and possible personal injury or
property damage. The information con-
tained in this catalog is offered as a
guide to assist in making the proper
selection of a pressure gauge. Addition-
al information is available from Dresser
Instrument Division.
Pressure Ranges:
As recommended by ASME B40.1,
select a gauge with a full scale pressure
range of approximately twice the nor-
mal operating pressure. The maximum
operating pressure should not exceed
approximately 75% of the full scale
range. Failure to select a gauge range
within these criteria may ultimately re-
sult in fatigue failure of the Bourdon tube.
Operating Conditions:
The operating conditions to which a
gauge will be subjected must be con-
sidered. If the gauge will be subjected
to severe vibrations or pressure pulsa-
tion, liquid-filling the gauge or the
PLUS! option may be necessary to
obtain normal product life. Other than
discoloration of the dial and hardening
of the gasketing that may occur as
ambient temperatures exceed 150°F,
non liquid-filled Type 1279 (phenolic
case), 1377 and 1379 (aluminum case)
Duragauges with standard glass win-
dows, can withstand continuous operat-
ing temperatures up to 250°F. Liquid-
filled gauges can withstand 200°F but
glycerin fill and acrylic window will tend
to yellow. Accuracy will be affected by
approximately 1.5% per 100°F. Gauges
with welded joints will withstand 750°F
(450°F with silver brazed joints) for
short times without rupture, although
other parts of the gauge will be
destroyed and calibration will be lost.
Proper selection of the Bourdon system
material is dependent on the process
fluid to which the system will be subject-
ed. If the correct material is not avail-
able, the use of a diaphragm seal may
be necessary to protect the system
from the process fluid. Liquid-filled
gauges are recommended for the dis-
charge side of positive displacement
pumps.
Pressure Elements:
Available in a wide variety of materials,
including: phosphor bronze, alloy steel,
316 stainless steel, K Monel and Inconel.
Cases:
Four solid front case types are offered.
Solid front cases have a solid wall
between the Bourdon tube and the win-
dow. The 1279 and 1379 Duragauge
cases are field convertible by means of
a kit. These gauges can be converted
to hermetically sealed or liquid-filled.
Buna-N seals at the front and rear of
the case provide resistance to aggres-
sive atmospheres.
Rings:
The ring, which retains the window, is
threaded, bayonet (cam), or hinged,
depending upon case type.
Movements:
Movements are designed and materials
of construction selected to reduce friction
and extend wear life. The Duragauge’s
stainless steel movement is a rotary
geared design with Teflon coated wear
parts.
Dials:
Dials are uniformly graduated and have
highly legible black markings. A pointer
dial stop pin at the 7:00 o’clock position
is standard.
Windows:
The standard is glass on dry gauges
and acrylic on liquid-filled gauges.
Options are laminated safety glass,
non-glare glass or acrylic.
Pointers:
Duragauge pressure gauges have bal-
anced micrometer adjustable pointers
which can be repositioned without
removal from the pinion shaft.
8
Viton, ® Teflon, ® Kalrez, ® Kynar ® – DuPont Trademark
Carpenter 20 ® – Carpenter Steel Trademark
Inconel, ® Monel ® – Huntington Alloys Inc. Trademark
Hastelloy – Cabot Corp. Trademark
Nickel
® – International Nickel Co., Inc. Trademark
Halocarbon ® – Halocarbon Products Co. Trademark