7 Product Selection
Ashcroft
Test Gauges
Cases : Six different case styles andthree different materials are offered alu-
minum alloy, fiberglass reinforcedpolypropylene, and phenolic. Two typesare offered, open and solid front. The
open front Type 1084 case is constructedwith the dial between the bourdon tubeand the window, with a pressure relief
opening between the socket and thecase. The solid front cases supplied onall other test gauges provide increased
safety with a solid wall between the bour-
don tube and the window. The entire rearof the gauge is covered with a stainlesssteel pressure relief back. Should the
Bourdon tube fail due to overpressure,corrosion or fatigue, the wall directs pres-sure buildup through the rear of the case
and away from the dial and the window. Bourdon Tube Pressure Elements: Available for a wide variety of media
applications; materials include phosphor
bronze and K-Monel
STANDARDCASESTYLE TYPE 1082 Consult ASME B40.1 for guidance in
Dials : Aluminum dials have highly legibleblack markings on a white background.
Each test gauge dial has a mirror bandwhich eliminates parallax errors when thepointer and its reflection are aligned.
External adjustable dial available in stan-dard case style 1082(*)S.
gauge selection
WARNING: Pressure Ranges
Suppliers of pressure gauges should beselected considering media and ambient
operating conditions, to prevent mis-
application. Improper application can be
detrimental to the gauge, causing failure
and possibly personal injury or property
damage.The information contained in this catalogis offered as a guide to assist in makingthe proper selection of a test gauge. : For process applica-tions, select a gauge with a full scale
pressure range of approximately twicethe normal operating pressure. The maxi-mum operating pressure should not
normally exceed 75% of the full range.For laboratory applications, where cyclingis less frequent, the range of the test
gauge may be the same as that of theinstrument under test. Pointers : Balanced knife-edge tip point-ers, supplied with all test gauges, allow
precise and easy readings. All are light-weight to maintain a high standard ofaccuracy. Type 1082 and 1084 pointers
include a red tip for enhanced readability. Windows : The standard window for Type1082 test gauge is glass. Non-glare glass
is optional. Acrylic windows, also option-al, are more resistant to impact breakagethan glass windows. Safety glass, also
optional, will not fracture into manypieces as will ordinary glass. Window forType 1084 is polycarbonate. Operating Conditions : To ensure longlife and accurate readings, pressure
gauges should not be exposed to pro-cess or ambient temperatures over 150F.This is especially true of gauges with liq-
uid filled cases due to thermal expansionof the case fill fluid. Long term exposureto temperatures in excess of 150F may
cause discoloration of dials and fill fluids,as well as hardening of elastomeric caseseals and possible fill leakage. Soft sol-
dered, silver brazed and welded pressure
joints are rated at 250F maximum,450F maximum and 750F maximumrespectively. Plastic gauge cases, includ-
ing phenolic should not be exposed totemperatures in excess of 250F. Accuracyof temperature compensated Type 1082
gauges will be affected by approximately
0.005% per degree F and accuracy of allother test gauges will be affected byapproximately 0.015% per degree F. Rings : The ring, which retains the win-dow, is threaded, bayonet (cam) or
hinged, depending upon case type. AllType 1082 windows have a gasket toprotect the internal mechanism from
outside environments.
. Movement: All gauges 4
1 ⁄
2 ˝ size and larg-er feature a rotary geared movement, the
most efficient and positive method oftransmitting mechanical motion. Moving
parts are designed and protected toreduce friction and wear. All movements
are ultrasonically cleaned and lubricatedto guarantee smooth operationand toresist wear associated with high vibration
and/or pulsation. Span, linearity, and zeroadjustments are easily made to assurecontinued accuracy of all Ashcroft test
gauges.