General Information
• Open the lead of the bath.
• Position the sensor of digital thermometer in the socket which is provided on the one side of sub-zero temperature bath. Please refer sketch.
• Pour acetone in the bath up to 30 to 40 mm height.
• Place the specimen, self centering tong inside the bath dipped in acetone. To avoid rise of specimen temperature it is advisable that the ends of the tong are also dipped in the bath along with the specimen which will reduce heat transfer from tong to the specimen.
• Take a cylinder of CO2 (Carbon dioxide) or liquid Nitrogen-Qty. 1 itr.
• Pass CO2 Gas into Instant Dry Ice Maker unit. The CO2 gas will get converted into dry ice cake. Remove the dry ice cake from ice maker unit add this ice slowly into the acetone bath.
• Stir the acetone in a bath uniformly and observe the temperature on the digital thermometer. Continue this process till the required temperature i.e. ( - 40 Degree Centigrade) or as per specification of ASTM / LS / BS / EN Standard.
• Now reduce the quantity of dry ice addition just to maintain the bath temp. M fixed point for 10 minutes minimum.
• Hold the specimen to be tested in the self centering tong.
• Confirm that the machine is ready in all respect for conducting the test and the pendulum hammer is in the lifted / latched position.
• Transfer the specimen from bath onto the Anvil support and confirm that it is centered by the self centering tong correctly
• The test has to be completed within 5 seconds from the removal of test specimen from sub-zero temperature bath till pendulum hammer hits to the charily specimen.
• After completion of test immediately keep self centering tong into sub-zaro temperature bath and note down the abaorbed energy on dial. Continue the next test as per above procedure.
