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(I)
Basic Technical Information |
The chemical
composition and properties of Borosilicate
glass 3.3 characterised by their high
heat-resistance and chemical stability,
is as defined by the international standard DIN ISO 3585. Borosilicate
glass represents unmatched standardized
glass for construction of plant and
piping in the chemical, dyestuff, food
pharmaceutical, petrochemical industries.
Its steadily growing use is due to many
advantages over conventional materials.
• Outstanding corrosion resistance
• Smooth pore free surface.
• Transparency
• Catalytic inertness.
• No effect on taste and odour.
• Physiological inertness.
Products made from Borosilicate 3.3
glass are smooth, non-porous and perfectly
transparent, with no catalytic action,
and are corrosion-resistant even in
demanding operating conditions up to
300°C without sudden changes of
temperature.
Borosilicate 3.3 glass, which we use
is an environment-friendly product and
is completely harmless from an ecological
point of view.
Approximate
Chemical composition of Borosilicate
3.3 glass |
Component |
Amount
(% by mass) |
SiO2 |
80,4 |
B2O3 |
13,0 |
Al2O3 |
2,4 |
Na2O
+ K2O |
4,2 |
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Chemical
Properties of Borosilicate
3.3 Glass |
Products
made from Borosilicate 3.3 glass are
chemically stable, practically inert
and characterised by high resistance
to the effects of water, water vapour,
acids and salt solutions and relatively
high resistance to alkalis.
The glass gets etched by hydrofluoric
acid and concentrated Phosphoric acid
and corroded by hot concentrated aqueous
NaOH solution. Constant alteration
of acid and alkaline environments
increases corrosion.
The chemical resistance of Borosilicate
3.3 glass is specified by the ISO
3585 and is evaluated precisely
by the international standard testing
methods defined by ISO and DIN ISO.
Chemical resistance of Borosilicate
3.3 glass |
Hydrolytic
resistance at 98 °C (in
accordance with ISO 719) |
Hydrolytic
Resistance grain class ISO
719-HGB1 |
Hydrolytic
resistance at 121 °C (in
accordance with ISO 720) |
Hydrolytic
Resistance grain class ISO
720-HGA1 |
Acid
Resistance (in accordance
with ISO 1776) |
Sodium
oxide (Na2O)
< 100 µg per 1 dm2 of glass when the glass “as
a material” is tested
(including preliminary acid
treatment) |
Effects
of a boiling aqueous solution
of mixed alkalis (in accordance
with ISO 695) |
Alkali
resistance class ISO 695-A2
or better |
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Physical
Properties |
The
physical properties of Borosilicate
3.3 glass, as shown in the following
table, as per ISO 3585standard.
Mean
coefficient of linear thermal
expansion (ISO 7991) A20/300 |
3,3
×10-6 K-1 |
Density
p |
2,23
g.cm-3 |
Thermal
conductivity (at 100 °C)
w |
1,2
W.m-1.K-1 |
Mean
Specific heat capacity at
constant pressure cp between 20 and 200 0C |
0,8
kJ.Kg-1.K-1 |
The mechanical
properties and service life of products
made from Borosilicate 3.3 glass are
largely determined by the condition
of the surface, especially its finish
& integrity , i.e. the depth of
damage to the surface in handling and
secondary heat treatment.
Scratch
hardness of glass on Mohs scale |
6 |
Allowable
tensile stress with flame polished
surface without any scratch
or damage or alteration during
service. |
10
Mpa |
Allowable
tensile stress with grounded
or flame polished surface where
alteration and scratches are
possible during service. |
7
Mpa |
Allowable
compressive stress |
100
Mpa |
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WORKING
PRESSURE FOR GLASS PIPELINES
VESSELS |
The
glass system is designed as per EN BS
1595, AD 2000 Merkblatt, PED & ASME Section VIII Division I where ever relevant and the permissible internal working
pressure (MAWP) depends on the nominal
diameter of the glass components and
on working temperature. In case of assembled
units comprising of vessels, filters,
heat exchangers, etc. the overall permissible
internal pressure is limited by the
lowest pressure, which one of the components
of the assembly can withstand.
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WORKING
TEMPERATURE |
Borosilicate
glass retains its mechanical strength
over a range of temperature and will
deform only at temperature, which approach
its strain point. The practical upper
limit for operating temperature is much
lower and is controlled by the temperature
differentials in the glass surface,
which depends on the external surroundings
too. Provided borosilicate glass is
not subject to rapid changes in temperature,
creating undue thermal shock, it can
be operated safety at temperatures up
to 250 °C. The high resistance of
products made from Borosilicate 3.3
glass to sudden changes of temperature
- their heat resistance - is due to
a low coefficient of linear thermal
expansion, a relatively low modulus
of tensile elasticity E and relatively
high thermal conductivity. It must be
realized that assembled plants are composed
not only of borosilicate glass, but
also have other materials such as PTFE
the recommended max. operating temperature
is 200°C. Operating temperatures
may have to be modified so as to compensate
for the effects of other factors such
as pressure, thermal cycling, rapid
heating cooling etc.
The degree of thermal shock (usually
defined as sudden chilling or heating),
which it can withstand depends on many
factors such as stresses due to operating
conditions, stresses imposed in supporting
the equipment, the wall thickness of
the glass. It is therefore undesirable
to give sudden temperature changes.
But up to 120 °C can be accommodated.
At sub-zero temperature, the tensile
strength of borosilicate glass tends
to increase and equipment can be used
with safety at temperatures as low as
-50°C.
Our technical cell would be glad to
furnish you any other information you
might be looking for. Please contact
us at consult@bizvalueresources.com for this.
We can supply you total assembled pilot
plants designed and engineered as per
your requirements. Also all components
for plants are available in the major
designs prevalent in the international
market. You can have a look at the components
& equipments, which are available
as standard products by following the
links given from this page.
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(II)
Design & Manufacturing
Practices |
For design, fabrication & testing we strictly adhere to EN BS 1595, AD 2000 Merkblatt & Directives of CE namely PED - 97/23/EC, Machine Directive - 98/37/EC, European Low Voltage Directive - 73/23/EEC, EMC Directive - 89/336/EEC and ASME Section VIII Div. I.
GMP regulations call
for special care in both the planning
and selection of the components together
with the materials of construction used
for them, a design without any dead
space, which ensures that components
drain fully and can be cleaned easily
and effectively. We fully comply with
such requirements by maintaining the
shape of the components, the way they
are installed and selection of suitable
valves. Where the external surfaces
of complete assemblies have to comply
with clean room requirements, appropriate
stainless steel coupling and support
material can be supplied.
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