Textile Technocrats
To Determine physical properties of different materials and products at elevated temperature may be carried out by heating the test specimens to the appropriate temperature inside a constant temperature air oven and determining the required characteristics with the specimens kept under the same temperature. For this purpose the equipment needed for conducting the determination can either be kept inside the oven along with the test specimens, or, if this is not feasible because of certain constrains, by taking the heated specimens out from the oven and conducting the test in staillair within the shortest possible span of time.
The Hot Air Oven has a test chamber of double walled instruction. The inner walls are made of SS 304 sheet and outer walls of MS Sheet powder coated. The space between the two walls is filled with fibre glass wool for insulation. The chamber is fitted with three adjustable perforated shelves for keeping the test specimen or the test equipment on.
The oven is heated electrically with the help of heaters placed in ribs on the bottom and sides of the chamber, an air circulating fan is provided on the back of the chamber for even temperature distribution. The temperature inside the test chamber is controlled with a digital temperature controller (TIC).
The chamber is provided with two ports with adjustable openings for enabling natural change of air inside it by convection. These parts can also be used for providing electrical access to the test specimens kept inside the oven, is so desired.
TECHNICAL DATA
Inner Dimensions of test chamber : 18” x 18” x 18”
Range of temperature : Ambient to 250o C.
PROCEDURE
Determination of effect of ageing
1. Set the TIC at the desired ageing temperature and switch on the electric supply. As soon as the TIC cuts off, note the temperature.
2. Switch off the supply. Open the door of the oven and place the test specimens on the shelf or suspend them from a suitable jig placed inside the oven if so specified. Close the door of the oven quickly. Switch on the power supply.
3. Allow the temperature of the oven to rise to the desired test temperature. As soon as the temperature of the oven reaches the desired test temperature, note the time. Allow the test to continue uninterrupted for the specified duration of time. At the end of this period, switch off the power supply and remove the test specimens from inside the oven.
Condition the aged test specimens at the specified conditioning temperature for not less than 24 hours and not more than 96 hours in a strain free state in accordance with the details given in the appropriate test method for the properly being studied. After conditioning, conduct, the required test on the test specimens and compared the results obtained against these obtained from used test specimens.
