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 mould ed 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

Interlabs 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 Interlabs glassware. When heated above 500° C the glass may acquire permanent stresses on cooling. All Interlabs labware is annealed in modern ovens under strictly controlled conditions to ensure minimal residual stress in the products.

Chemical Durability

Interlabs 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.

Care and Maintenance

When treated with proper care Interlabs laboratory apparatus will give a long and satisfactory service. The following prepared notes are to assist users in obtaining the maximum life and performance from their apparatus. Our sales department will be happy to advise on any aspect concerning the safe use of our products.

HEATING AND COOLING

Glass may suffer damage in three ways:

»	It may break under thermal stress in the steady state, that is when there is established constant thermal gradient through the glass.
»	It may break under the transient stress of a 'thermal shock', that is sudden heating or cooling.
»	It may, if heated beyond certain temperature, acquire a permanent stress on cooling which could cause subsequent failure.

The following precautionary measures will assist in avoiding failures during heating and cooling procedures.

1.	Never leave vessel unattended when evaporation work is being carried out. The vessel may crack or explode as dryness condition is approached if the heat source is not adjusted correctly. Lower the temperature gradually as the liquid level drops.
2.	Always use caution when removing glassware from a heat source and avoid placing on a cold or damp surface. Although the ware can withstand extreme temperatures, sudden temperature changes may cause the vessel to break.
3.	Always cool vessels slowly to prevent thermal breakage.
4.	Never apply heat to badly scratched or etched vessel as the thermal strength will have been greatly reduced.
5.	Never apply point source heating to a vessel as this will greatly increase the chance of breakage.
6.	Always diffuse the heat source by using a metal gauze or air/water bath. Alternatively ensure even heating of the vessel by slow movement of the vessel in relation to the heat source.
7.	Adjust Bunsen burner to get a large soft flame. It will heat slowly but also more uniformly. Uniform heat is critical factor for some chemical reactions.
8.	Ensure that the flame contacts the vessel below the liquid level. Heating above that level will invite breakage of the vessels.
9.	Always use anti-bumping devices in the vessel, such as powered pumice or glass wool rapid heating of the vessel and contents is required.
10.	Never use material with sharp edges such as broken porcelain as an anti-bumping device. This will cause internal abrasions and reduce the mechanical and thermal strength of the vessel.
11.	Thick walled glassware should not be subjected to direct flame or other localised heat source. Vessels of this type are best heated with the use of an electric immersion heater.
12.	Avoid heating glassware over electric heaters with open elements. Uneven heat of this type can include localised stress and increase the chance of breakage.
13.	Remember that the hot plate will retain heat long after the appliance has been switched off.
14.	Always ensure that the surface of the hot plate is larger in area than the base of the vessel being heated. An under-sized plate of the job in hand will invite uneven heating and promote breakage of glassware.
15.	Always ensure that manufacturer's instructions are Bollowed when electrical heat sources.

Mixing and Stirring

1.	Always use a policemen's or similar device on stirring rods to prevent scratching the inside of a vessel.
2.	When using a glass vessel with a magnetic stirrer always use a covered follower to prevent abrading the inside of the vessel.
3.	When using glass or metal mechanical stirrer in a glass vessel always predetermine the height of the stirrer before use to ensure there is no contact between the stirrer blade and the bottom or sides of the vessel.
4.	Never mix sulphuric acid and water inside a glass measuring cylinder. The heat of reaction can break the base of the cylinder.

Vacuum and Pressure

1.	Never use a glassware beyond the recommended safe limit.
2.	Always use a safety screen when working with glassware subjected to pressure of vacuum,
3.	Never subject glassware to sudden pressure changes. Always apply and release positive and negative pressures gradually.

General infomration

FAST AVAILABLE ITEMS

Items which are available faster are marked by * in the catalogue. Though it does not indicate any definate period of delivery, these items can be manufactured faster than the other items of its range. For example, Pipe section PS18/1000 can be supplied faster than any other pipe section of 450DN. This is because of following reasons:

Semi finish goods or row material for these items will be always avilable.
Method of production of these items are set.
Being fast moving items, these items may be available ex-stock with us.

REPAIRS

Though any damaged glass equipment can be repaired, mostly it is not economical to do so. Generally the repair which involves less than a third of its original work, is worth to carry out repairing. Repair work is costly because:

It generally require greater skill than making a new one.
Since it involves high risk of total breakage, the risk of total loss of time spent on its repairing goes alongwith.
The work involved in receiving a damaged equipment, identifying it throughout the handeling, cleaning it, estimating its repairing charges, re-estimating the repairing charges in case damage extends etc are relatively expensive.
Each job require individual attention throughout the execution.

However, while sending an equipment for repairing, following care must be taken:

Inform the nature of breakage and get an estimate of repairing charges in advance to avoid the loss of transportation expenses in case it is uneconomical to go for repairing.
Since repairing takes longer time to fit into production schedules and completion of repairing is highly uncertain,it is generally suggested to arrange for a subsitute equipment to continue the work.
Equipment to be repaired should be clean. Since it can be cleaned better and at less cost at owner's premises. It should be cleaned befor sending it for transportation. This also makes it safer to transport.
Pack with extra care, since cracks in glass have a tendency to extend with every jerk.
If Possible, send broken pieces alongwith it.
Generally repairing work is accepted only for the equipment manufactured by us,and are repaired at owner's risk only.

DIMENSIONS,WEIGHTS AND SPECIFICATIONS

In this catalougue, dimensions, weights and other specificaions are taken more or less in accordance with Corning. This is to keep the flexibility of maximum interchange ability. However, some difference are anavoidable due to local manufacturing conditions. All the odd dimensions are rounded off.

All the dimensions and weights are approximate. The specifications given in the catalogue are intended to present a general description of the items. Since manufacturing of glass equipment involves all manual operations, certain tolerances are obvious and permissible while passing the items through quality control.

CATALOGUE REFERENCES

To avoid querries and delays in delivery, please always quote the catalogue reference in your order.

MODIFICATIONS

We reserve the right to carry out technical modifications of products and data mentioned in this catalogue as and when require.

STANDARDS PRACTICED

DIN ISO	3585
DIN ISO	3586
DIN ISO	3587
DIN ISO	4704
BSEN	1595
DIN ISO	718

Strong Joints

Introduction

Tapered glass joints are predominantly used in industrial glass equipments. This design has a high ratio of radial to axial force, which frequently leads to breakage while tightening the flange joints.

A cylinder can withstand a much higher axial force than radial force plus glass has a very high compressive strength. We at Interlabs recognized these features and by our innovative design practices developed STRONG joints. The STRONG joints are so designed that the harmful radial stresses are dramatically reduced . For a given axial force the radial forces are 14 times lesser than that in tapered joints.

STRONG joints are parctically many times stronger then conventional tapered joints, As far as tightening of joints are concern, it is tested that a STRONG joint does not break even at a torque of 20Nm, as against tapered joints, which starts breaking at 6-7 Nm torque. At times it may happen that because of over tightening, a metal backing flange breaks or the threads of nut-bolts give way but STRONG glass joint remains intact.

Most of the old glass installations in general contain equipments with tapered glass joints. STRONG joints are fully compatible with these tapered joints i.e. an STRONG equipment can replace another tapered equipment and vice versa in any existing unit. This interchangeability makes STRONG design more adaptable in general conditions and change over cost is negligible .

STRONG joints

STRONG joints have been developed, to arrest the frequent breakage and leakage problems. The STRONG joints are so designed that the harmful radial stresses are dramatically reduced. For a given axial force the radial forces are 14 times lesser than that in tapered joints.

In addition to reducing the stresses, the STRONG joint has the following advantages :


	The ovality of the glass flange, present due to manufacturing process, has virtually no effect because the backing flange isn't ind direct contact with the periphery.
	Continuous re-tightening of the backing flange or insert,due to bolting force & temperature effects,hence dismantling is easy. Also much smaller length threaded bolts are needed compared to the tapered joints.
	The STRONG joint is leak-tight at all design temperatures & pressure, even with temperature cycling and frequent plant start-up as it is possible to tighten the joints upto at tightening torque of 20 Nm as against 6-7 Nm tightning torque in tapered joints. In some cases the metal backing flange breaks but nothing happens to the glass components ! With so many benefits and particularly low breakage risk, we have adopted Strong design for all equipments manufactured by us. Strong is widely accepted and adopted by users as well as manufactures of Glass Equipments in India.

DIMENSIONS OF STRONG ENDS

DN	D2	D1	D	H1	H2	A	B
25	41	26	34	13	8	65	9
40	56	39	49	14	9	65	9
50	69	51	62	16	11	65	9
80	98	77	91	18	12	65	9
100	132	105	123	20	17	65	9
150	184	154	166	22	19	65	9
225	258	220	233	24	26	65	9
300	340	308	315	24	26	65	9
400	463	405	425	25	35	65	9
450	525	455	499	25	50	78	9
600	684	600	640	25	60	65	9

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.

Borosilicate glass is chosen for its unique chemical and physical properties. Borosilicate glass can be considered as being composed of oxides. Silica (SiO₂) Magnesia (MgO) and lead oxide (PbO) are the principle modifiers/fluxes.

The chemical and physical properties of any glass depends on a varying degree on chemical composition of glass.

CHEMICAL COMPOSITION

The composition of borosilicate glass used for chemical plants has following approximate composion.

SiO₂ - 80.6%

B₂ O₂ - 12.5%

Na₂O - 4.2%

Al₂O₃ - 2.2%

RESISTANCE TO CHEMICAL

Borosilicate glass is inert to almost all materials except hydroflouric acid (HF) phosphoric acid((H₃Po₄) and hot strong caustic solutions. Of these Hydroflouric acid has the most serious effect, even when it is present in PPM (parts per million) in solutions. Where as phosphoric acid and caustic solutions cause no problems when cold but at elevatrd temprature corrosion occurs. in case of caustic solutions upto 30% concentration can be handled safely at ambient temperature.

Under actual operating conditions, the effect of turbulence, and traces of other chemicals in the solution may increase of decrease the rate of attack. So it is not possible to give exact figures for corrosion by caustic solutions.

THERMAL PROPERTIES

Linear coefficient of thermal expansion

The coefficient of thermal expansion of borosilicate glass over the temperature 0 - 300°C is 3.3 x 10-6/°C. This is very low when compared with other glasses and metals. That is why, borosilicate glass is often called low expansion borosilicate glass.

Specific heat

Specific heat between 25°C and 300°C is average to be 0.233Kcal/Kg, °C

Thermal Conductivity

Thermal conductivity is 1.0 Kcal/hr,m°C. Over the permissible operating temperature range.

ANNEALING

Annealing of glass is the process where the glass is heated and kept for a defined period of time to relive internal stresses. Careful cooling under controlled conditions is essential to ensure that no stresses are reintroduced by chilling/cooling.

RESHAPEING

In the given below are shown characteristic temperature at a determined viscosity, essential for glass reshap.

Lower cooling temperature

10²⁴ poise

515°C

Upper cooling temperature

10¹³ poise

565°C

Softening point

10⁷ poise

795°C

Reshapeing point

10⁴ poise

120° C

MECHANICAL PROPERTIES

The lack of ductility of glass prevents the equalization of stresses at local irregularities or flaws and the breakage strength varies considerably about a mean value. This latter is found to occur at a tensile strength of about 700kg/cm2

In order to allow for the spread of breaking stress, a large factor of safely is applied when determining the wall thickness requirement to allow operation up to values given in the table of working pressure.

OPTICAL PROPERTIES

Borosilicate glass show no appreciable absorption in the visible region of spectrum and therefore appears clear and clour less.

In photo chemical processes the transparency of ultra violet is of particular importance. It follows from the transmittance of material in uv region that photo chemical reactions such as chlorination & sulpho chlorination can be performed in it.

PERMISSIBLE OPERETING CONDITIONS

The permissible internal operation pressure depends upon the nominal diameter of the glass components and on working temperature.

In case of unit with various combination like vessels, filters, heat exchangers, the over all permissible internal gauge pressure is always governed by the components with the lowest permissible operating gauge pressure. All components are suitable for full vaccume.

Bar is a mesure of absolute pressure. The figure given for maximum recommeded working pressure represent pressure above atmosperic.

WORKING TEMPERATURE

Borosilicate glass retains its mechanical strength 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 which depends on the relative temprature defferentials in the glass which depends on the relative temprature of the contens of the equipment and the external surroundings. Provided borosilicate glass is not subject to rapid change in temperature, creating undue thermal shock, it can be operated safety at temperatures up to 250 °C.

It must be realised that in complete plants, composed not only of borosilicate glass, but also includ 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 accomodated.

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 for STRONG and components.

COMPOSITE MATERIALS

The last two decades have seen the new or further developments of particularly corrosion resistant plant construction materials. Typical examples of these are PTFE, tantalum, titaniu, graphite and of course, Borosilicate 3.3 glass.

The combination of different corrosion resistant materials with the utilization of the specific advantages of each permits both safe and economic construction.

Borocilicate glass/PTFE

Borosilicate glass with PTFE is of particularly decisive importance for construction of glass installation for example. In Seals, Bellows, Stirrers, Pumps, Heat exchangers, Columns Inserts etc.

PTFE is used with Glass because of its excellent mechanical & thermal properties. They have near universal fluid compability. Wear life when compared with others is very low. Particularly PTFE is maintenance free and have cryogenic stability with non wetting property.

Service temperature of PTFE is considered as - 50°C to +200°C

ELECTRICAL CHERETERISTICS

Glass being a poor electrical conductor, surface, conductivity is insignificant and varies with the quantity of water absorbed on glass surface. The specific conductivity is 10°ohm/cm at temperature of 200°C.
The dielectric coefficient varies with current frequency.

DENSITY

Density of glass at 20°C(J)=2.23g/cc
Modulus of elasticity (E)=6.3 KN/mm2
Poissions ratio=0.2

EXTRA PROTECTION OF GLASS COMPONENTS 'X BONDING'

X BONDING provide an added advantage of protection of standard glass components. The major advantage of X-Bonding systems is that if the glass is subject to accidental breakage, the bonded wrapping provides additional protection against the risk of injury, release of corrosive fluids or loss of expensive products.

X BONDING is a glass reinforced fibre coating which provide a higher level of protection on the glass components. This does have a slightly adverse effect on the transparency of the glass, making it translucent & not transparent.

Permissible Operating Temperature:

The permissible operating temperature for X-Bonding is 130’ C unless limited by the individual operating temperature of the said component.

Permissible Operating Pressure:

The permissible operating pressure for X Bonded components is same to that for standard glass components.

Thermal Shock

Despite the thermal insulating effect of X Bonding, the thermal shock characteristics remain the same as standard glass component.