for practicing the process application_number US 77733485 A description the apparatus shown contains a temperature control or tempering chamber 3 and a pump 12 driven by a drive 20 which pump is connected via connecting hoses 10 11 to the tempering chamber 3 as can be seen in fig2 pump 12 has two pump chambers 18 19 which are in each case closed with a diaphragm 16 17 an actuating part 15 is fixed by means of screws to diaphragms 16 17 and is provided with a slot in which extends a cam 14 this cam is located on a shaft 13 driven by the drive 20 and is rotated in the direction of the arrow shown in fig2 the connecting hoses 10 11 are in each case connected to one of the chambers 18 19 and extend in tempering chamber 3 into sectional chambers 6 7 at a limited distance above the bottom thereof through said bottoms the air passages 4 5 extend downwards out of the tempering chamber 3 whilst the upper ends of the air passages 4 5 terminate well above the connections for the connecting hoses 10 11 in sectional chambers 6 7 tempering chamber 3 is surrounded by an electrical heating jacket 26 and in its wall is located a temperature sensor 27 with the aid of which and by means of a diagrammatically represented thermostat 8 the heating of the tempering chamber is chosen in such a way that in the sectional chambers 6 7 the desired temperature is maintained the air passages 4 5 are removed at the bottom from tempering chamber 3 in such a way that on positioning a sample container 1 below the outlet of air.