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Accredited calibration services:
From -196oC to 1000oC ASTM thermometers, digital thermometers, PRTs, thermocouples, thermistors
Specific Gravity
hydrometers. API hydrometers, Baume hydrometers,
ASTM Class 1 and OIML E-2 and lesser specification stainless steel and brass laboratory weights. New calibrated weights and re-calibration of weights you currently have.
Thermo-hygrometers, chart recorders, humidity sensors, data-loggers
Burets, pipets, volumetric flasks, graduated cylinders, volumetric glassware
Testing and certification that an instrument complies with specified accuracy requirements...
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CANNON®
INSTRUMENT COMPANY GLASS
CAPILLARY VISCOMETERS ALL
VISCOMETERS are SUPPLIED WITH CANNON® INSTRUMENT company’s A2LA
ACCREDITED ISO/IEC 17025 REPORT OF CALIBRATION
Why does
CANNON® offer so many different types of glass capillary viscometers?
Primarily because no single capillary viscometer
is ideally suited for all kinematic viscosity determinations.
Individual analysts also have their own preferences.
The brief
descriptions on the following page may assist you in determining which
viscometer is most appropriate for your particular application. Expanded
Uncertainty Instead of
listing the precision of Cannon® glass capillary viscometers, we now
provide the expanded uncertainty. This
is the universally accepted statistic when dealing with calibration data. In
order to obtain A2LA accreditation, it is necessary to determine and specify the
expanded uncertainty. ISO
publications define expanded uncertainty as “the interval about the result of
a measurement within which the values that could reasonably be attributed to the
measurand may be expected to lie with a high level of confidence.” The use of
expanded uncertainty instead of precision does not reflect any change in the
accuracy or quality of Cannon viscometers.
It is a statistical term that is more comprehensive than precision.
When comparing the accuracy of viscometers it is essential that the
expanded uncertainty be specified. A
certificate specifying the expanded uncertainty is provided with every
calibrated viscometer. We also
supply such a certificate with every bottle of viscosity standard. CANNON® GLASS CAPILLARY VISCOMETERS - TYPES Follow the blue links below for full information, photos and ordering information. Cannon-Fenske Routine The Cannon-Fenske Routine viscometer is a rugged and inexpensive viscometer that works well if the liquid to be measured is transparent or translucent. In general, if the meniscus (the curvature at the top of the liquid column) can be readily observed through a column of liquid 3-mm in diameter, the Cannon-Fenske Routine viscometer and other transparent-type viscometers (such as the Zeitfuchs Transparent and BS/U-Tube viscometers) can be used. Ubbelohde The Ubbelohde viscometer and other supended level viscometers
are also used to measure transparent liquids.
Unlike the Cannon-Fenske Routine viscometer, suspended level viscometers
possess the same viscometer constant at all temperatures.
This property is advantageous when measurements are to be made at a
number of different temperatures. CANNON
has improved the design of the Ubbelohde viscometer to make a more rugged
instrument called the Cannon-Ubbelohde viscometer.
Other suspended level viscometers in this bulletin include the BS/IP/SL,
BS/IP/SL(S), and BS/IP/MSL viscometers. Reverse
Flow Viscometers Special viscometers have been designed for testing opaque
liquids. These reverse flow type
viscometers wet the timing section of the viscometer capillary only during the
actual measurement. The Cannon-Fenske
Opaque, Zeitfuchs Cross-Arm, and BS/IP/RFU-Tube viscometers available from
CANNON Instrument Company are all reverse flow types. Reverse flow viscometers must be cleaned, dried, and refilled
before a repeat measurement can be made. By
contrast, other viscometer types commonly used to measure transparent liquids
allow the sample to be repeatedly drawn up into the capillary, permitting
duplicate measurements. Small Volume Viscometers In some situations, such as in a clinical laboratory, the amount of liquid available for measurement is quite small. Several viscometers have been designed which require one milliliter or less of liquid. These are refered to as semi-micro or micro viscometers. The Cannon-Manning Semi-Micro is a U-tube viscometer that has been modified to measure the kinematic viscosity of samples as small as 1.0 mL. The Cannon-Ubbelohde Semi-Micro viscometer is a modification of the standard size Cannon-Ubbelohde viscometer requiring a sample volume of only one milliliter. The Cannon-Manning Semi-Micro Extra Low Charge viscometer will permit kinematic viscosity determination with as little as 0.5 milliliters of sample. Dilution
Viscometers Estimates of the molecular size and shape of large polymer
molecules can be obtained from kinematic viscosity measurements of dilute
solutions of the polymers. The
Cannon-Ubbelohde Dilution viscometer has an extra-large reservoir which allows
polymer solutions to be diluted several times.
Dilute polymer solutions frequently appear to exhibit changes in
kinematic viscosity when the shear rate is changed. By using the Cannon-Ubbelohde Four-Bulb Shear Dilution
Viscometer, measurements can be made at four different shear rates. Vacuum
Viscometers In most glass capillary viscometers, the samples flow under
gravity. When liquids are too
viscous to flow readily under gravity, vacuum viscometers may be used to measure
viscosity (in mPa•s or cP). In
these instruments a vacuum is applied to one end of the vicscometer to pull the
liquid through the capillary into the timing bulb(s). CANNON offers several type of vacuum viscometers, including
the Cannon-Manning Vacuum, the Asphalt Institute Vacuum, and the Modified
Koppers Vacuum. Like the Cannon-Fenske
Opaque viscometer, these are all “reverse flow” viscometers. Vacuum viscometers require a vacuum that is very accurately
controlled.
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