Abstract: A method for removing soot or the like adhered to heat transfer tubes of a heat-exchanger by providing a steel ball scatterer above the heat transfer tubes and intermittently scattering steel balls towards the heat transfer tubes, is improved. The improvements reside in that a steel ball scattering rate is set to a small initial rate at the commencement of the scattering operation and thereafter is increased either in a stepwise manner or continuously. Preferably, within a main body casing of the heat-exchanger, a plurality of steel ball collision preventing plates having their central portions extending convexly upwards are provided between the steel ball scatterer and the heat transfer tube group, in order to prevent fins of the heat transfer tubes from being damaged by steel balls falling from the steel ball scatterer and directly colliding against the fins.

Abstract: The present invention is a process for recovering solvent vapor which comprises absorbing solvent vapor in a first absorbing liquid, and subsequently stripping the solvent vapor to regenerate the first absorbing liquid. The stripped solvent vapor may be reabsorbed in a second absorbing liquid. The second absorbing liquid may be under greater than atmospheric pressure. Regenerating the first absorbing liquid may occur at pressures only slightly below atmospheric pressure, i.e., a low vacuum, by recycling the absorbing liquid to a regenerator. Because the regenerating process does not require the use of a high vacuum, the gas recovery apparatus may be more economically constructed and operated.

Abstract: An improved process for recovering a combustible gas including a first means for measuring the relative concentration of combustible gas and combustion-supporting gas before the gaseous mixture enters a gas recovering apparatus, and a second means for determining the relative concentration of combustible gas and combustion-supporting gas after the gaseous mixture leaves the gas recovering apparatus. The first gas detecting means prevents a gaseous mixture containing a combustible gas in a concentration less than the U.E.L. from entering the gas recovering apparatus. The second detecting means controls the gas recovering apparatus to insure that the concentration of combustible gas never falls below the upper limit of the detonation range.

Abstract: A novel method for compressing mixed gas consisting of combustible gas and air without risk of explosion of the mixed gas is described herein. In the novel method, the mixed gas is compressed under coexistence of non-combustible liquid such as water. In one preferred embodiment, a water-sealed compressor as represented by a Nash pump is used for compressing the mixed gas, and water contained in the compressed mixed gas is separated and fed back to the water-sealed compressor to assure existence of sealing water in the compressor.

Abstract: A process is provided for recovering a solvent vapor from a mixed gas of the solvent vapor and air. From a vessel storing a mixed gas of the solvent vapor and air, the mixed gas is passed through a compressor to be compressed to a low degree, the resultant compressed mixed gas is introduced to a first absorption column, where said compressed mixed gas is brought into contact with a first absorbent to absorb and recover a greater part of the solvent vapor. A gas coming out from the first absorption column is introduced to a second absorption column, where said gas is brought into contact with a second absorbent.