Sealing of cavity on reagent tray

Abstract

A thermal reaction apparatus for sealing liquid within cavities includes a tray having cavities for storing therein liquid. The cavities have openings arranged at varying levels in thickness direction of the tray. A planar sealing member is disposed on the tray to cover the openings and is comprised of a pair of flexible sheets and viscous fluid filled between the flexible sheets. A pressure plate is disposed on the planar sealing member for applying thereto pressure effective to locally flow the viscous fluid to enable the sealing member to seal the varying levels of the cavity openings to thereby prevent evaporation of the liquid stored in the cavities. Alternatively, the elastic sealing member is comprised of an elastic sheet and projections arranged in registration with the respective cavities, and the pressure plate is disposed in contact with the projections for applying there to pressure effective to deform locally the sealing member through the projections to enable the sealing member to fittably seal the cavity openings. Or, the pressure plate may have projections, instead of the sealing member, in contact with the planar sealing member in registration to the respective cavities.