Water filled cavities are dried by replacing the water with a first liquid which is miscible with water and this is then replaced by a second liquid which is miscible with the first and which has a high vapor pressure. The second liquid is then replaced by a gas. The invention is particularly useful for removing water from between members which are to be explosively welded together underwater so as to improve the quality of the welded joint obtained.
A method of removing water from organic solid substrates, such as peat, wherein a primary solvent is used to extract water from the substrate and a secondary solvent is used to separate the primary solvent from the water.
A method for joining parts of metal by diffusion welding comprises initially the establishing of a joint between the opposed bounding surfaces, the joint having generally increasing height from the periphery towards the middle. The joint is provided with a connection to an external source for flushing gas and a vacuum source. During the preliminary heating and pressing together of the parts the joint is supplied with an inert for reducing flushing gas, e.g., hydrogen, until the joint by diffusion welding is closed along its periphery. Thereafter, a vacuum may be pumped in the joint, where upon further heating, quick compression and a certain holding time provide complete diffusion welding of the parts. It is also suggested to reduce the cross-section of the parts in the joint area and press these out to their original cross-section during the diffusion welding.
