Abstract

An apparatus and method for spraying a cryogen in which a heat load is sprayed with a cryogen from one or more spray nozzles within a spray zone. A heat conductive element is positioned below the article and is provided with a surface sized to catch the liquid content of the cryogen that has been oversprayed, thereby to vaporize the overspray through direct heat transfer with the conductive element. In another aspect the present invention provides an apparatus and method in which a flow network a flow of a liquid cryogen is divided into first and second subsidiary streams. The second subsidiary stream is vaporized within a branch of the network and then mixed back into the first subsidiary stream to produce a two phase flow of the cryogen. The cryogen is then sprayed as the two phase flow. The flow rate of the second subsidiary stream can be controlled with a proportional valve to adjust the quality of the cryogen being sprayed so that pooling of overspray on said heat conductive element is inhibited.