an automatic calorimeter mainly comprises a constant temperature calorimeter, microcomputer calorimetric control software and the like. it is a multifunctional automatic calorimetric measurement instrument capable of being controlled by computer software and conducting data processing. the instrument is characterized by high measurement accuracy, convenience in operation, reliability in use and the like and mainly applied to measure the calorific value of such combustible materials as coal, petroleum, chemical, food, wood and explosive, etc.
calorific value (calorific capacity) test
precisely weigh 0.9-1.1g (accurate to 0.0002g) of analytical samples (less than 0.2mm) in a combustion vessel.
for the test samples spattered easily during combustion, wrap the samples by lens wiping paper with the known weight and test; or press the samples by a cooked flake wrapping machine and cut into 2-4mm blocks for later use. for the test samples unlikely to combust completely, place an asbestos pad at the bottom of the combustion vessel, or take asbestos wool as the pad (pave a layer of asbestos wool at the bottom of the vessel and compact by hands). no pad is required for the quartz combustion vessel. in case the combustion is still incomplete with the pad, one feasible method is to improve the oxygen charging pressure to 3.2mpa; and the other feasible method is to wrap the weighed test samples by the lens wiping paper with the known weight and calorific value, compact with the hands and put the samples into the combustion vessel.
connect both ends of the ignitor fuses to electrode masts; make sure that the both ends contact with the test samples well (less foundation shall be provided for the coals that are easy to sputter and combust); ensure that the ignitor fuses shall not contact with the combustion vessel so as to avoid forming the short circuit to cause ignition failure or combustion of the combustion vessel or the electrode masts; and pay more attention to preventing the short circuit between the two electrodes as well as between the combustion vessel and another electrode.
add 10ml of distilled water to the oxygen bomb, screw the oxygen bomb cap and put on the oxygen charger slightly so as to prevent the positions of the combustion vessel and the ignitor fuses from changing due to vibration; charge the oxygen to the oxygen bomb slowly by the oxygen charger till the pressure is 2.8-3.0mpa, in which the oxygen charging time is not smaller than 15 seconds. if the oxygen charging pressure exceeds 3.3mpa due to carelessness, stop testing instantly, discharge the oxygen completely and charge the oxygen again till the pressure is below 3.2mpa. when the oxygen pressure in a steel bottle is reduced to below 5.0mpa, the oxygen charging time shall be prolonged properly; and when the pressure is below 4.0mpa, a new oxygen bottle shall replace the former.
put the oxygen bomb into the internal cylinder, cover the upper cover of the calorimeter, input the sample weights and click the software start button so that the system start the test; after test, the results are calculated by the software automatically and displayed by the screen.
input each parameter of the test, in which the parameters can be input during test or after test; after test, the parameters can be changed; after the parameters are changed, the results are calculated automatically by the system according to the new parameters.
calorific capacity test
the process of the calorific capacity test is identical to that of the calorific value test.
the benzoic acid shall be dried for 3 days preliminarily by a drying vessel with concentrated sulfuric acid or dried for 3-4 hours by a drying oven at 60-70 deg c. and then cooled for pressing.
when more than 5 test samples are provided, the system automatically decides whether the results are suitable for international requirements; if so, the final results shall be given and stored as the calorific value parameters automatically