Measuring
Cylinder
Class
B Spout Cylinder
Class
A Spout Cylinder
Class
B Stoppered Cylinder
Class
A Stoppered Cylinder
Measuring cylinders are used for measuring volumes of mobile
liquids. For viscous liquids or semi-solids a conical measure
is easier to use. There are a variety of types and styles
of measuring cylinder, and below is a brief guide to which
is appropriate.
For basic measurement of liquids in qualitative work a Class
B cylinder is sufficient. Typical usage might be measuring
solvents for reactions, making up solutions or adding an excess
of a reagent. Used in schools, universities and research laboratories.
For more accurate measurement of liquid a Class A cylinder
is appropriate. Class A cylinders are calibrated to half the
tolerance of Class B cylinders and each has a unique serial
number for traceability. A certificate of accuracy traceable
to national standards can be provided if required. Class A
cylinders are used in analytical labs, quantative labs, and
other controlled environments. They are not suitable for work
which requires accuracy of less than 1%. For this a bulb pipette
(0.2%) or a gravimetric method (0.0001%+) should be used.
Stoppered cylinders are used for
making up solutions where it is important to homogenize the
liquid by shaking. They are also useful for measuring volatile
solvents where significant evaporation might occur if the
liquid is exposed to air. Class B are used for qualitative
work and Class A for quantitative work, similar to the spout
cylinders above.
|