Bulletin 8735/37 Page 2
SIZING and INSTALLATION — Select gauge for double the range of anticipated pressures. Note: Maximum accuracy is obtained in the middle third of the gauge range. — For shutoff when gauge is not being read, install a valve ahead of each gauge. LIQUID FILLED GAUGES Advantages — The liquid absorbs vibration as well as pulsation and spikes in pressure. — The dampening action of the liquid enables the operator to take readings during conditions of rapid dynamic loading and vibration. — The liquid lubricates all moving elements, dramatically reducing wear in the movement. — Because most liquid-filled gauges are filled with non-aqueous liquid and hermetically sealed, they perform in corrosive environments and are immune to moisture penetration and icing. Also, shock effects are lessened.
and decreases case pressure. As a result, accuracy can be de- creased and the pointer may not return to zero properly until the gauge is vented to atmosphere. To vent liquid filled gauges, move the lever to the open position which will release any pressure or vacuum build up in the case. The gauge should always be installed in an upright position. The lever can be left in the open position.
Ordering Instructions
Use gauge designation in the selection chart for ordering ¼” NPT pipe connection versions. For ¼ BSPT pipe connection versions, simply add an “M” to the front of the part number in the selec- tion chart. For example, to order the ¼ BSPT version of 8735-15I, simply order M8735-15I. Metric versions will not be stocked, therefore will have longer delivery times. For gauges with special ranges, scales, dial sizes and materials contact the engineering department.
Commissioning into Service
For liquid filled pressure gauges, case venting (after the gauge is installed) is necessary to preserve the accuracy. Temperature fluctuations during shipment and in the process application cause the liquid filling to expand and contract which in turn increases
NORTH AMERICAN DIFFERENTIAL PRESSURE GAUGES
Used to measure low air or gas pressures--positive, negative (vacuum), or differential. They are accurate within ±2% of full scale throughout range (at 70°F). Their design has high resistance to shock, vibration, and over-pressures. Gauges can be flush- or surface-mounted with standard hardware supplied. A 4 ½" hole is required for flush panel mounting. Although calibrated for vertical position, ranges above 1"w.c. can be used at any angle by simply re-zeroing.
DIMENSIONS inches
1 11⁄16
½
11⁄16
Pressure
½
INCHES OF WATER
.40 .60
.20
.80
Pressure
0
1.0
1 ¼
4 ½
4 ¾
1 /
7⁄16
2
Suction
Suction
DIMENSIONS SHOWN ARE SUBJECT TO CHANGE. PLEASE OBTAIN CERTIFIED PRINTS FROM FIVES NORTH AMERICAN COMBUSITON, INC. IF SPACE LIMITATIONS OR OTHER CONSIDERATIONS MAKE EXACT DIMENSION(S) CRITICAL .
WARNING: Situations dangerous to personnel and property may exist with the operation and maintenance of any combustion equipment. The presence of fuels, oxidants, hot and cold combustion products, hot surfaces, electrical power in control and ignition circuits, etc., are inherent with any combustion application. Components in combustion systems may exceed 160°F (71°C) surface temperatures and present hot surface contact hazard. Fives North American Combustion, Inc. suggests the use of combustion systems that are in compliance with all Safety Codes, Standards, Regulations and Directives; and care in operation.
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