We are offering borosilicate glass tube.
the advantages of using glass process plant & pipeline components as abasis for the construction
of complete process systems have long been recognised throughout the world’s chemical pharmaceuticals, foods,drinks and allied industries.details of glass components which are part of noble product range can be found in the following chapters.
all glass iteams shown in this catalogue are manufacturured from borosilicate glass. The key property of this glass whichcontains approximately 81% silica (sio2) and 13% boric acid (b203) has superb chemical resistance and high resistance to thermal shock.
since this glass have lower co-efficient of thermal expansion, the tensile stresses in the glass wall during heating are less which means that it is able to withstand a greater thermal shock and the higher working pressure for a given operatibg temperature.
the growing use of borosilicate glass asa meterial of construction is a direct result of the following properties when compared to other materials of construction.
• superior corrosion resistance
• smooth pore-free surface
• catalytic inertness
• no influence on odour and taste
• physiological acceptability
• non combustibility
• ecological acceptability
borosilicate glass plant and pipeline is used in both internal pressure and vacuum applications.
chemical composition :
the borosilicate glass used in the manufacture of our range of process plant and pipeline components has the following approximate composition.
sio2 - 80.6%
b2o3 - 12.5%
na2o - 4.2%
al2o3 - 2.2%
others - 0.5%
chemical properties :
borosilicate glass is highly resistant to water, acids, salt solutions and organic substances and also to halogens such as chlorine and bromine. Its resistance to alkalis is also comparatively good.
noticeable corrosion of the glass surface is caused only by hydrofluoric acid, hot concentrated phosphoric acid and strong alkalis at evevated temperatures.
the co-efficient of the thermal expansion of borosilicate glass over the temperature 0-300 deg.c is 33 x 10/c. This is very low when compared with other glasses & metals.that is why borosilicate glass is often called low when page: 1 compared with other glasses and metals. That is why borosilicate glass is often called low expansion borosilicate glass.
specific heat between 25 deg. C and 300 deg.c is averaged to be 0.233 kcal/kg.c.
thermal conductivity is 1.0 kcal/hr.m. C over ther permissible operating temperature range.
mechanical properties :
the crucial mechanical property of borosilicate glass is that its compressive strength is high and tensile strength is high and tensile strength is low. For exampal, glass plants should be supported from the lowest practical position.
whilst the average braking tensile stress of the borosilicate glass with polished surface is approximately 70n/mm2 the allowable design stress is considerably lower.
glass is brittle material of construction which means that rapisly applied stresses such as impact cannot be absorbed by local ductile deformation, which is the case with metals.the surface condition of glass components has a major influence on the strength because mechanical tensile and bending stresses are greatest at this surface.the smoothness of a glass surface can be considered as a mechanical property. The surface roughness ranges fromn zero to a few which in engineering terms means completely smooth. This means that pressure drop due tofriction is extermely low and equations for technically smooth pipes are used.it is important to note that due to the chemical resistance and physical passivity of borosilicate glass, the hydraulic smoothness is retained over long periods of time and any fouling of the surface reduced and can easily be removed.
with borosilicate glass, the transmission of ultra-violet light which is of grat importance for photo chemical reactions is some what grater in the middle spectrum that with normal window glass. The chlorine molecule absorbs in the range 280 to 400 rm which means that many light catalysed reactions such as chlorinations and sulphochiorinations can be carried out in glass plant.
annealing of glass is the process where the glass is heated and kept for a defined period of time to relive internal stresse.careful cooling under controlled conditions is essential to ensure that no stresses are reintroduced by chilling.
permissible operating conditions:
borosilicate glass retains it’s mechanical strength and will deform only at temperatures which approach its strain point, approximately 510 deg.c.the permissible operating temperature is however, considerably lower normally at about 200 deg.c. Provided that there is no temperature shock.
uneven, rapid heating and sudden cooling of hot glass companents must be avoided because of high tensile stresses which would be generated in the process fluids is 1 20 deg. C and may be further reduced, depending upon components shape and wall thickness.
the maximum working pressure is a function of diameter,wall thickness, shape and operating temperature. The maximum working pressure is for a complete plant is determined by the lowest rated components in the system.all component are suitable for operation at full vaccum over the entire temperature range.full vaccum in this context means the lowest pressure which can be achieved by the vaccum generating equipment.
the maximum working pressure for a working temperature of 200 deg. C is shown below.
working pressure for glass pipeline & vessel.
as a result of the properties of borosilicate glass as a construction material, noble equipments are particularly suitable for the following units operations & processes of chemical engineering.
• batch distiliation
• continuous distilliation
• reactions like bromination, chlorination, sulfonation etc.
• heat transfer
Delivery Time : with in one week