Device for automatically carrying out temperature cycling.

A device for automatic performance of polymerase chain reactions in a plurality of reaction containers, each reaction container is closed with a lid and containing a predetermined volume of a liquid reaction mixture, which apparatus comprises the following components:a) a support (33) having an arrangement of chambers (27) for receiving the reaction vessel (21), each chamber being adapted to receive the lower part of a reaction vessel, and wherein, the support (33) made of a material that a high thermal conductivity, and that it has a top surface, a bottom surface and a cylindrical outer wall, each of said chamber (27) of the carrier (33) has an opening which is located in the upper surface of the support,b) arranged in the chambers (27) of the carrier (33) reaction vessel (21) which are each closed with a lid (87),c) a computerized control and regulating device, andd) controlled by the control and regulating device has means for cyclic alteration of the temperature of the support, which means comprise at least one Peltier element (36). To achieve a uniform temperature in all the reaction vessel and reduction of the dimensions of the device and its power consumption, the device being characterized in that(I) the arrangement of the chamber (27) is annular in the carrier (33),(Ii) the at least one Peltier element (36) is thermally connected to the lower surface of the support, and(Iii) which is pressed at least one Peltier element (36), by a central spring-biased fixing (41, 42, 43, 44) against the carrier (33), which fixing exerts a force on the center of the Peltier element (36 ) exerts a by a screw (42) pressed spring (41) whose tension can be adjusted with the screw.