Abstract: Process for the preparation of melamine from urea via a high-pressure process in which dry melamine powder is obtained by transferring the melamine melt leaving the reactor to a vessel in which the melamine melt is cooled by means of ammonia characterized in that the melamine melt is sprayed into a cooling vessel and cooled by droplets of evaporating liquid ammonia which is sprayed into the same cooling vessel at a pressure above 0.1 MPa and a temperature between 50° C. and the melting point of the melamine in the cooling vessel.

Abstract: This high-pressure, high-temperature anhydrous process prepares melamine from urea. It is a primary object of the present invention to provide a highly energy-efficient and improved continuous process for the production of melamine from urea which utilizes a simplified process to produce and recover a high-grade (96 to 99.5% purity) melamine as a dry powder directly from liquid melamine melt. Molten urea is supplied to a reactor maintained at high temperature (700.degree. to 800.degree. F.) and high pressure (1700 to 2200 psig) whereby melamine, CO.sub.2, and NH.sub.3 are formed. The reactor effluent stream containing liquid melamine, CO.sub.2, and NH.sub.3 is transferred to a gas separator where CO.sub.2 and NH.sub.3 containing melamine are separated and cycled to a scrubber unit for scrubbing with molten urea reactant to remove the melamine before transfer of the CO.sub.2 and NH.sub.3 gases at high pressure to an adjacent urea plant for utilization in producing urea.

Abstract: A cassette of the type having opposing interior surfaces relatively movable toward and away from each other to prevent and permit, respectively, movement of a photographic sheet therebetween, and having at one end an opening through which the sheet can pass along an exit path, has at its opposite end a device engageable with a corner of the sheet remote from the opening and movable at an angle with the exit path to urge the sheet obliquely toward and against a side wall of the cassette, so as to induce buckling of the sheet and consequent separation thereof from the interior surfaces, thereby facilitating succeeding movement of the sheet along the exit path and out through the opening. The device is externally accessible for manual actuation, and the extent to which it can be moved without encountering sheet resistance indicates, visually and tactilely, whether or not a sheet is in the cassette.