Abstract: A solvent recovery treatment method of adsorbing at least two kinds of solvent-gas containing gases different in solvent content concentration, wherein: a rarefied solvent-gas containing gas is first passed through a first adsorbing device; the rarefied gas passed through the first device is switched to be passed through the second adsorbing device after a predetermined time has elapsed while a dense solvent-gas containing gas begins to be passed through the first adsorbing device; the rarefied gas passed through the second device is switched to be passed through a third adsorbing device after the predetermined time while the dense gas passed through the first device is switched to be passed through the second absorbing device, and the first adsorbing device is made to perform regenerating operation. The above operations are successively repeated according to necessity.

Abstract: A method of dissolving a powder material is disclosed in which the material is wholly dissolved and the existence of bubbles in the resultant solution is greatly minimized. An agitating blade stirs a liquid in an air-tight tank while the powder material is inserted into the liquid. The pressure is then reduced in the tank causing large bubbles to swell. The bubbles are destroyed by the agitating blade. The pressure reducing operation is then turned off so that the bubbles do not leave the tank through a pressure reduction port. The pressure reducing operation is then repeated a number of times to dissolve the powder material and to destroy bubbles.