VERCON FIBRE GLASS TUBE
The Vercon Glass Tube is used in Capillary Tube Technology in the Ceramic Industry. The tube is manufactured with high temperature resistant glass yarn in round flexible form as per requirement of diameter in such a way that the compressed hot air when released at high pressure passes out easily to take out water from the precipitated plaster of paris filled in moulds.
Test Characterestics.
1. Construction : (a) Sleeve:-The tube is of ‘E’ type Glass Sleevings with braided construction in unilateral direction.
(b) Coating :- The coating shall be of any resin resistant to high temperature, non-releasing grade and compatible to porcelain moulds.
2. General Appearance :
Material is of uniform diameter, highly flexible and without any knots, blister and kinks.
3. Colour :-
Normally available in white or natural colour.
4. Dimension:
4.1 Bore Dia:- The bore shall be determined with apluge gauge of length atleast three times the bore dia or 20 mm which ever is greater.
The gauge shall enter the bore without the use of undue pressure. A lubricant in power from shall assist. The Sleeve is held vertically with the guage at the bottom and the point of Support sufficiently above the end of gauge to abode pressing The specimen on it.
| ∅ C | A | B | ∅ D | |
|---|---|---|---|---|
| 7MM | A/TO 10 | 30 | 12 | 12 |
| 8MM | A/TO 12 | 30 | 12 | 12 |
| 10MM | A/TO 15 | 30 | 15 | 15 |
4.2 Wall thickness:- A plug gauge or mandrel shall be inserted so that it enters freely but has a dia not less than 80% of the bore. The over all dia is measured with micrometer, while measuring pressure applied by the micrometer shall be just sufficiently to close the sleeving on to inserted plug gauge or mandrel. The Wall thickness shall be calculated by having the difference between the plug gauge or mandrel diameter & the overall dimension. Following other methods can be utilized.
a) Optical profile Projector
b) Optical Comparator
c) A suitable Micrometer.
5. Resistance to splitting after heating:
5.1 Number of Test Specimens :- Three Sprecimens shall be tested.
5.2 Form of test Specimen:-Three specimens shall be produced by cutting rings whose cut length equals the wall thickness. Precautions shall be taken to ensure that the cut is clean since imperfections can affect the result.
5.2 Procedure:- The specimens shall be tested using a mandrel papered sufficiently at one end to enter the bore. the specimens shall be maintained for a period of 168+ 2 hr at a temperature of 70+ 2 C or such other temperature as may be specified. And then allowed to cool to 27 + 5C. They shall then be rolled up the mandrel so that they are extended by an amount equal to the percentage of nominal bore diameter specified. The specimens shall be kept in that positon and at a temperature 27+ 5C for 24 + 1 h and then examined for signs of splitting when examined under diffused light.
6. Resistance to Heat:-
A length of approximately 75 mm of Sleeving shall be Heated for 4 h + 10 min in an oven at the temperature as may be specified. The Sleeving shall be allowed to cool to room temperature and examined for any signs of dripping, cracking, flowing.
7. Loss in mass on heating Of Uncoated Textile Class Sleeving:
7.1 Number And Mass of Test Specimens:- Three specimens shall be tested, each consisting of a sufficient length to provide 5 + 1 g.
7.2 Procedure:- The Specimens shall be conditioned by heating at 105 C+ 2 C for one hour and then allowed to cool in discolor to room temperature. They shall then be weighted to the nearest of 0.0002 g (m1) then heated in a ventilated furnace at 600 + 10 C for 60 to 75 min. After cooling ina desiccator to room tempratarure the sprecimen shall be reweighed (m2)
8. Resistance to mould Pressure at elevated Temperature:
8.1 Number of Test Specimens:- Three specimens shall be tested. The tests shall be carried out not less than 16 h after manufacturing of the Sleeving.
8.2 Form of Test Specimen:- The test specimen shall be formed by slitting the Sleeving alon its length and then cutting from the Sleeving a section approximately 10 mm x 5mm (or the full circumference of the Sleeving if this is less than 5mm) so that the long axis of the specimen is parallel to the length of the Sleeving.
8.3 Apparatus:- The apparatus consists of an instrument capable of measurement to + 0.01 mm with a rectangular indentor blade with an edge 0.70 mm + 0.01 mm which applied a load to the specimen of 1.2 N + 0.05 N unless otherwise specified. The specimen is placed on a metal mandrel 6.00 + 0.01 mm in diameter which is supported on a V block. The essential features of the assembly are shown in figure.
The assembly shall be placed in a uniformly heated air oven maintained at 110 + 2 C during the heating period unless another temperature is specified. To minimize vibration a gravity-circulated oven mounted on suitable damping pads shall be used.
8.4 Procedure:- The wall thickness of the test specimen shall be measured by the be method except that the plug gauge and Sleeving sample therein shall be replaced by the test specimen resting on the mandrel. The wall thickness shall be the measured difference between the mandrel diameter and the overall dimensions.
The assembly with mandrel but without the test specimen shall be conditioned for at least two hours before the test in the oven at 110 + 2 C unless another temperature is specified.
The indentor blade shall be raised. the test specimen placed on the mandrel with its long axis parallel to the mandrel and the indentor gently lowered on to the surface of the test specimen.
The assembly and test specimen shall then remain in the over at the specified temperature for 60 + 5 min.
The position of the indentor shall then be recorded. Remove the specimen, allow the indentor to rest directly on the mandrel and again record the position. Subtract the difference between these two readings from the indentation. Difference between any two of the three value for the position of the indentor resting directly on the mandrel shall not be more than 0.02 mm.
9. Volatile content of silicone Coating:
9.1 Number and mass of Test Specimen:- Three Specimen shall be tested, each consisting of a Sufficient length to provide 10 + 1 g.
9.2 Procedure: The specimens shall be weighed to the nearest 0.01 g (m1) and then heated in a ventilated oven at 150 + 2C for 4 + 1h. A convenient way to achieve this is to suspend the test pieces over a wire that is thermally insulated from metal work of the oven.
After cooling in a desiccator, the specimens shall be Reweighed (m2)
10.Bending after Heating:
10.1 Number of Test specimen:- Three specimens shall be tested each of length sufficient to wind conveniently round a mandrel of the size specified in the Sleeving under test.
10.2 Form of Test Specimen:- When the nominal bore does not exceed 15 mm (or other value specified in a particular type of sleeving) the specimen shall be filled by any means suitable ( for example, a number of wires) to prevent undue collapse of the sleeving during winding.
When the nominal bore exceeds 15 mm (or other value specified in a particular type of Sleeving) the specimen shall consist of a strip of sleeving 6 mm wind cut parallel to the longitudinal axis of the Sleeving.
10.3 Procedure: The specimen, filled when so required by the previous paragraph, shall be suspended for 478 + 1 hour uniformly heated air oven maintained at the temperature specified. It shall then be removed from the oven and allowed to cool to room temperature.
It shall then be wound without jerking for one complete turn in a close heix round a mandrel of the diameter as may be specified. For cut strips the inside surface shall be in contact with mandrel. The time to achieve one complete turn shall be not greater than 5 seconds. The specimen shall be held in this position for five minutes.
It shall then be visually examined without magnification with specimen still on the mandrel for sings of cracking, detachment of coating, delaminations or change of colour.
11. Miscibility to P.O.P.:- This test is carried out to find out adherence of various Sleeving with any grade of P.O.P. In order to study the life of mould. Test shall be carried out in lab with suitable pilot mould using 600 best P.O.P. mixed with water in ratio of 1.3 and pressure would at 60 psi pressure at 19 cm/metre. The mould so prepared shall be put in use upto 125 reckless and broken open to see the release of glass sleev from the mould. The sleeve shall not release from the mould oven on mild pressure.