Technical
Data |
| LOW
EXPANSION BOROSILICATE GLASS |
From the 16th Century to today, chemical research teams
have used glass containers for a very basic reason the
glass containers is transparent, almost invisible. And
so the contents and the reaction are clear visible,
But because chemists music heat, cool and mix chemical
substances, ordinary glass is not always adequate or
laboratory works. |
| |
Laboratory
works requires apparatus made in a glass - which can
readily be moulded into any desired shape or from which
offers maximum inertness when in contact with the widest
range of chemical substances, which can withstand thermal
shock with fracture and high temperature work without
deforming, and which will be resilient enough to survive
the everyday knocks to which it will be subjected in
normal laboratory handling, washing and sterilizing
processes. |
| |
| Chemical
Composition |
| Global
Labware Glassware is a low alkali borosilicate
composition. Its typical chemical composition is given
under. It is virtually free of magnesia-lime-Zinc group
and contains only traces of heavy metals. |
| |
Percentage
by weigh |
| SiO2 |
81 |
| B2O3 |
13 |
| Na2O |
4 |
|
| |
In
general the 'Strain point' should be regarded as the
maximum safe operating temperature of Global
Labware glassware. When heated above 500°
C the glass may acquire permanent stresses on cooling.
All Global Labware labware is annealed
in modern ovens under strictly controlled conditions
to ensure minimal residual stress in the products. |
| |
| Chemical
Durability |
Global
Labware Glassware in highly resistance water,
neutral and acid solutions, concentrated acids and their
mixtures as well as to chloride, bromine, iodine, and
organic matters. Even during extended period of reaction
and at temperatures above 100° C, its chemical resistance
exceeds tha of mot metals and other materials. It can
withstand repeated dry and wet sterilisation without
surface deterioration and subsequent contamination.
Resistance to attack of various chemicals is shown under.
Only hydroflioric acid, very hot phosphoric acid and
alkaline solutions increasinglly attack the glass surface
with rising concentration and temperature. |
| |
Contact
Chemical |
Duration
in hour |
Loss
in Wt. mg/m |
| Water
distilled at 100°C |
6 |
10 |
| Water
Vapour Steam at 121°C |
1 |
75 |
| Acid
HCI |
6 |
100 |
| 80%
H2So4at 130°C |
12 |
140 |
| Alkali
- 1N soln. of NA2Co3 boiling Infusion Fluids Isotonic |
6 |
4000 |
| Nacl(0.85%)
121°C |
2.5 |
70 |
| Glucose(5%)121°C |
2.5 |
50 |
|
| |
| Fabrication
with Borosilicate Glass |
Due
to low expansion of glass and easy workability, this
glass can be shaped, formed, joined into complicated
apparatus. It can be done even by an analyst in his
own laboratory. He can keep on changing till he gets
what he needs. In case where annealing in a controlled
oven is difficult he can do so b flame annealing which
is also great advantage. |
| |
| Optical
Properties |
| Laboratory
glassware made form Borosilicate Glass shows no noticeable
absorption in the visible region of the spectrum. It appear
consequently clear and colourless. |
| |
