Thermosil

THERMOSIL

DESCRIPTION

THERMOSIL High Density Arc and Heat Resistant Boards are manufactured from carefully selected and treated Raw Asbestos Fibers and special grades of Cement. The particular properties of the material are obtained by maintaining precision control of the blend, rate of mixing, addition of predetermined quantities of water and chemicals and then compressing the mix into sheet form under extremely high pressure. The sheets are then kept for maturing for several weeks under conditions of controlled humidity and temperature.

DISTINCTIVE PROPERTIES

THERMOSIL High Density Boards are a versatile material, which combine the following distinctive properties not available in any other individual material:

- Good thermal stability at high temperatures
- Low contact thermal shock thus eliminating fracture in items like glass components
- Low thermal conductivity
- High temperature resistance
- Good anti-tracking properties
- High arc resistance
- Ability to withstand high frequencies
- High strength even at high temperatures
- Extremely hardwearing leading to long life and infrequent replacement
- Smooth machineability without splitting or chipping
- Easy fixing by fasteners or adhesives
- Suitability as fire check barriers
- Good alkali resistance
- Non-metallic thus controlling problem of induced currents
- Availability in high thickness blocks of upto 75mm leading to convenient manufacturing of components
- Non-rusting

APPLICATIONS

The distinctive properties of THERMOSIL High Density Boards lead to their application in numerous diverse areas. Some of these applications are:

- As Arc chutes and deflector plates on air-break circuit breakers, contactors and fuse gear
- As spacer strips and end packing blocks in distribution transformers
- For the control and extinction of electric arcs
- For handling and transferring hot glass components in the molding area, conveyor systems and annealing lehrs.
- For manufacture of jigs, dies, moulds, guides, buffer strips, tubes, rods and other machined components
- As core plates in foundries and in furnaces
- For insulation of heated plattens in presses
- For insulation of coils, as top plate or support block in induction furnaces
- As guide strips or splashboards in handling of molten metals on hot castings
- For transportation of hot metal and pot line insulation in the aluminum industry
- As fire barriers or fire check doors

AVAILABLE GRADES

UNTREATED
Untreated THERMOSIL High Density Boards are available in the following grades:

HD-31 - General purpose natural grade suitable for most of the required applications.

HD-35 - Special grade for specific requirements. Only manufactured against order.

TREATED
The natural grade has high water absorption, which can result in unsatisfactory electrical insulation if used in situations where such water absorption can occur. Silicone Resin impregnated material
(SR Grade) is recommended for such applications. This eliminates the necessity of coating the edges with varnish after cutting.

Silicone Resin has been chosen because it has a higher operating temperature in comparison to other available Resins.

The minute pores in the Boards are filled with Silicone Resin, increasing the electrical strength and lowering moisture absorption from 15% to about 1%. There is some deterioration in the arc resistance properties but they still remain fairly. There is also some burning of Resin at the point of contact with the arc but this is localized and is self-extinguishing.

SR grade does not replace HD grades but is intended for applications where superior electrical properties are required such as in arc chutes and barriers for H.V. air break switchgear.

SR grade is available in thickness range of 3.2 mm to 38 mm

Other grades like oil impregnated or bitumen impregnated can also be supplied.

TECHNICAL DATA FOR UNTREATED GRADES

Property

Unit

Nominal Thickness (mm)

3.0-5.0

6.4-12.5

Over 12.5

Mechanical Properties

Density (Nominal)

Tensile Strength (min.)

Shear strength (min.)

Flexural Strength (min.)

Ultimate Crushing Strength (min.)

Compression Yield (min.)

Water Absorption (min.)

gms/cc

kgf/cm²

1.95

200

400

450

1500

1.95

190

380

410

1400

1.95

180

350

1250

3.5

Electrical Properties

Dielectric Strength in Air at 90^° C (min.)

Surface Breakdown in Air at 90^° C

KV/mm

1.7

>10

0.8

>10

Thermal Properties

Carbon Arc Tester

Spirit Burner test

Thermal Conductivity

Continuous temp. Usage

Secs.

Kcal/mh^°C

^° C

DOES

0.6

350

NOT

0.6

350

IGNITE

0.6

350

Specification Compliance
HD Grades meet the requirement of BS 3497 : 1979 & IS 4248

Sheet Size
1200 X 1050 mm (trimmed). Special sizes on request

Thicknesses Available

Nominal Thickness (mm)	Tolerance (mm)	App. wt per sheet (kg)	Nominal Thickness (mm)	Tolerance (mm)	App. wt per sheet (kg)
3.10 4.90 6.40 8.00 9.50 12.75 16.00	+-0.25 +-0.25 +-0.25 +-0.25 +-0.25 +-0.25 +-0.25	7.50 12.00 15.50 19.50 23.00 31.00 39.00	20.00 25.00 31.75 38.00 50.00 63.50 76.00	+-0.25 +-0.25 +-0.40 +-0.40 +-0.40 +-0.50 +-0.50	49.00 61.00 77.00 93.00 122.00 155.00 185.00

THERMOSIL ASBESTOS MILLBOARD

PRODUCT CHARACTERISTICS

Is made from a blend of high quality Canadian Chhrysostile asbestos fibers and other incombustible inorganic ingredients

* Is compactly bound
* Is strong with a smooth surface
* Is available in low thicknesses
* Has rigidity as well as flexibility
* Has low thermal conductivity
* Has high temperature resistively
* Can be easily cut, punched or wet moulded
* Gives clean edges while cutting gaskets

AVAILABLE GRADES

Grade TS-101/NE-1001
General-purpose grades for high temperature insulation. (Both grades have similar properties)

GradeTS-301
Superior grade for specialized e.g. automobile gaskets, sheet glass roller conveyors, padding in the steel strip industry etc.

GradeAL-111
Single lamination millboard made on a new Fourdrinier machine

GradeAL-333
Superior grade of single lamination millboard for automobile gaskets-available in rolls or sheets.

THERMOSIL ASBESTOS PAPER

Made from superior grades of asbestos fiber on state-of- art Fourdrinier machine used for electrical and thermal insulation available in roll form from 0.18 to 0.50 mm thickness

SPECIFICATION COMPLIANCE
* GOST 2850:1958
* JSS 5640-4:1975
* BHEL AA 21525 & PS21502B
* DGS7D G/Misc./81C
* OFM No. 62.020
* ASTM Classification: F 104 F 132000

APPLICATIONS

A versatile material used for widely divergent applications

For Insulation:
* In Electric Arc, Induction and other Furnaces
* In Boilers and Ovens
* In Kerosene Wick Stoves
* In Electrical Appliances like Domestic Presses
* In Steam and Hot Air Pipelines and Ducting

For Automobile Gaskets:
In Cylinder Head and Exhaust Manifold Gaskets

For Padding:
* In Ball Mills
* In Expansion Joints
* In Steel Strip Industry

For Construction of Roller Conveyors :
* In Steel Glass Industry
* In Annealing Furnaces

For Fire Safety:
* In Fire-proof Sates and Cupboards
* In Fire-check Doors

For Environmental Safety :
As Covers for Ladies, Pots, Ingots, etc. to protect workmen as Base Mat for placing Hot Metals

For Protection of Plant and Equipment:
As Gasket while pouring Molten Metals in Steel & Aluminum Industries as Lining below the Mould in the Casting Industry

Thermosil Asbestos Free Millboard
Made from eco-friendly raw materials various grades for different applications available against orders only

STANDARD SIZE
1mtr x 1mtr (other sizes available on request)
Below 0.8 mm in rolls of 1.2 mtrs. width

TECHNICAL DATA

Grades	TS-101/NE-1001	TS-301	AI-111	AI-333 & Paper
Thickness availability (mm)	1.5-25.0	0.75-12.5	1.0-2.0	0.18-2.0
Nominal Density (gms/cc)	1.15	1.10	1.08	1.08
Tensile Strength (min.) - Along grain (kg/cm²) - Across grain (kg/cm²)	28 12	45 24	36 18	45 28
Loss on Ignition at 800^°C	15%	18%	15%	18%
Thermal Conductivity at 150^°C mean temp. (W/m0C)	0.116	0.110	0.116	0.110
Moisture Content (max)	2%	2%	2%	2%
Electric Strength (Proof) in air at 90^°C	1.5kV/mm	1.5kV/mm	1.5kV/mm	2.0kV/mm
Temperature Resistance	500^°C or higher if suitably supported