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Pressure Gauge
Repairs |
We guarantee the quality of our work and provide a sound program for all makes
of pressure gauges and related accessories. We will restore any gauge to their
new or original condition. All gauges will be individually packaged and labeled.
Standard Repair Operation Procedures & Service Functions:
Clean all working parts of the gauge
Replace, where necessary, all dial, movement, case and link screws
Where deemed necessary by our inspection and test standards, replace any
severely worn or defective movement and/or link assembly with good workable
parts
Dead weight test and calibrate all gauges repaired
Replace all broken, cracked or blemished lenses
Clean all mounting threads
Clean and repaint the interior and exterior surfaces of the case and ring
Gauges found by our inspection to be beyond economical repair would be returned,
upon request, to our customer on a no charge basis
Guarantee
All Gauges following our servicing will have been dead weight tested and
calibrated. Gauges will be guaranteed to have accuracy equal to the
manufacturers' originally stated standard. |
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Installation
Prior to pressure gauge installation, the following conditions should be
considered: temperature, humidity, vibration, pulsation, shock, and
other climatic and environmental conditions of the application, as well
as the potential need for protective accessories and/or special
installation requirements.
Always use a wrench on the gauge socket when installing a NingFeng
pressure gauge into position; never use force on the gauge case to
tighten into position. This may result in a loss of accuracy, excessive
friction and/or mechanical damage to the measuring element and case of
the NingFeng pressure gauge. When surface or panel mounting a gauge, be
sure the surface is flat and the panel cutout and/or the mounting hole
configuration is correct (please refer to the NingFeng Pressure Gauge
catalog NK95G for these specifications). If the surface is uneven or the
panel cutout is larger than the gauges diameter, use an adapter ring to
remove mounting strain and/or adapt the gauge to the larger diameter
panel cutout. When connecting a gauge to a rigid pipe service, use
flexible tubing where possible as a connector to eliminate plumbing
strain. Rapid pressure pulsation and extreme mechanical vibration may be
damaging to some NingFeng pressure gauge movement gearing, bushings, and
linkage. In extreme cases, steps should be taken to dampen these forces.
In pressure ranges over 600 psi, a NingFeng orifice is recommended for
pulsation dampening, but in extreme pulsation applications a NingFeng
Piston Type Pressure Snubber may be required.
When installing a gauge into a corrosive situation be sure to select a
pressure gauge or pressure gauge and diaphragm seal combination suitable
for your application. Gauges to be used on high temperature service
should have a five foot or longer leg of pipe or tubing connecting the
gauge to dissipate heat and protect the gauge measuring element from
damage.
A gauge to be used on steam pressure service should be installed with a
water filled NingFeng pigtail steam syphon between the gauge and the
steam line.
Maintenance
Apart from occasional calibration, NingFeng pressure gauges require
little or no maintenance. Some applications may be more aggressive than
others, resulting in an increased frequency in the need for calibration.
The environmental limitations for the specific NingFeng pressure gauge
series should be observed in all cases, and gauges applied in situations
outside these requirements may result in premature wear and/or failure
of the gauge.
Warranty
All NingFeng pressure gauges carry a one or three year warranty.
NingFeng warrants for three years our 300, 500, 600, 700 and 900 series
liquid filled pressure gauges to be free from defects in materials and
workmanship, to remain within the cataloged accuracy and performance
specifications, and to maintain the integrity of the hermetically sealed
case preventing leakage. NingFeng warrants for one year our 100, 200,
400, 600, 700, and 800 series non-liquid filled pressure gauge. Certain
limitations do apply; for more information please consult page three of
the NingFeng Pressure Gauges catalog (NK95G).
Please do not hesitate to contact us with any additional questions.
Operating conditions including, but not limited to, system pressure,
media compatibility and ambient conditions must be considered when
selecting gauges and accessories. Improper selections and use of gauges
could possibly cause gauge failure and lead to possible property damage
or person injury. Refer to American National Standard ASME B40 for the
correct selection and use of gauges. A copy of this standard may be
obtained from the American Society of Mechanical Engineers, United
Engineering Center, 345 East 47th Street, New York, NY 10017.
Glycerine or silicone could result in a spontaneous chemical reaction or
explosion when combined with strong oxidizing agents including (but not
limited to) chlorine, hydrochloric or nitric acid and hydrogen peroxide.
Do not use glycerine or silicone filled gauges or accessories in these
types of service. Consult factory for application assistance.
In keeping with and for the purposes of product and/or manufacturing
improvements, NingFeng reserves the right to make design changes without
prior notice.
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Fluid Composition
Pressure Fluid Composition
Copper alloy (brass) or stainless steel is the standard wetted parts
(materials in contact with the pressure media) available on most
pressure gauges. Since the sensing element of a pressure gauge may be
exposed directly to the measured medium, consider the characteristics of
this media. It may be corrosive, solidify at various temperatures, or
contain solids that may leave deposits inside the sensing element. For
pressure fluids that will not solidify under normal conditions or leave
deposits, a standard bourdon tube gauge may be acceptable. Otherwise, a
seal gauge or gauge with a chemical seal/gauge protector should be used.
Case & Housing
Gauge Case & Housing
Stainless steel, black ABS, painted steel, brass and aluminum are
standard case materials, Select a material suitable for your
application. Stainless, brass, or ABS cases are recommended for outdoor
service. Most standard gauges have a dry case (no liquid fill), while
industrial and process gauges have a glycerine fill option available.
Front Ring & Window
Front Ring & Window
The front ring can be made of acrylic, stainless steel, brass, steel,
etc. The viewing window is held in place by the front ring. Some rings
are a permanent crimp design, while others can be removed providing
dial/pointer access for recalibration or repair. The ring which retains
the window is bayonet, threaded, snap-on or with screws, depending on
the application and case type. Window materials are typically clear
acrylic, polycarbonate, flat glass or safety glass.
Dial/Pointer
Dial/Pointer
The pressure scale is printed on the face of the dial. The pointer
typically moves clockwise to measure pressure and counter clockwise to
measure vacuum. Some gauges offer adjustable pointers for recalibration.
Test gauges offer a mirrored band on the dial and a knife-edge pointer
making it easy to take very accurate readings.
Temperature/Ambient Conditions
Temperature/Ambient Conditions
The normal ambient temperature range for most standard dry or silicone
filled gauges is -40 to +140 degrees F. The normal ambient temperature
range for glycerine filled gauges is -4 to +140 degrees F. The error
caused by temperature change is +/-0.3% per 18 degrees F rise or fall,
respectively. The correction is for the temperature of the gauge, and
not the temperature of the measured medium. Steam and other hot media
may raise the safe working limits of the gauge. In these cases, syphons,
cooling towers, or chemical diaphragm seals may be required. Moisture
and weather effects must also be considered. Liquid filled gauges
prevent condensation build up. Stainless steel, brass or plastic cased
gauges are recommended for outdoor use.
Liquid Filled Option
Liquid Filled Option
Liquid filled gauges help absorb vibration and pressure spikes,
increasing the service life of the gauge. The dampening action of the
liquid reduces pointer flutter and lubricates the internal parts,
dramatically reducing wear in the movement. Glycerine is the standard
fill fluid and provides the best performance in most applications.
Silicone has a low viscosity and works well when extreme temperature
fluctuation or icing is expected. The fill liquid must be compatible
with the gauge application.
Shock, Vibration, Pulsation
Shock, Vibration, Pulsation
Consider liquid filled gauges to enhance the reliability and integrity
of the measuring system when operating for long periods under extreme
operating conditions. In addition, optional pressure snubbers will
reduce pressure spikes and pulsation, pointer flutter and extend the
life of the gauge.
Chemical Diaphragm Seals/Gauge Protection
Chemical Diaphragm Seals/Gauge Protection
Diaphragm seals are used to isolate pressure gauges and transmitters
from clogging and/or corrosive media. Measurement of higher media
temperatures can be obtained by adding a seal. Diaphragm seal systems
can extend the life of the pressure instruments and reduce the cost of
installation and maintenance. Standard diaphragm seal bodies and
diaphragms are made of stainless steel (other materials available).
Chemical Compatibility Table
Chemical Compatibility Table
Use this Chemical Compatibility Table to make sure the gauge wetted
parts (parts in contact with the pressure media) are compatible with the
pressure media for your application. |
Copyright © 2003-2005,
Cixi Ningfeng Pressure Gauge Factory,
TBP
All rights reserved.
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