Abstract: Chemicals are recovered during the production of cellulose pulp by forming two different sulfidity melts in two different sections of a soda recovery boiler, and then producing cooking liquors from different melts in dissolving tanks. The liquors may be causticized and/or oxidized, or may be utilized uncausticized. Uncausticized green liquor having a sulfidity of about 70-90% may be used early in a kraft cooking cycle, followed by treatment with low sulfidity oxidized and causticized white liquor. In the continuous digestion of cellulosic pulp, oxygen may be added to the recirculation loops below the black liquor withdrawal to enhance the alkalinity of the slurry and to assist in delignification. Oxidized cooking liquor with low sulfidity can be added to oxygen bleaching and alkali extraction stages downstream of the digester, and a portion of the high sulfidity cooking liquor can be used to produce acid used in an ozone bleaching stage.

Abstract: A resist film coating apparatus comprises a resist receiving plate secured to a rotatable support plate carrying a wafer so as to be disposed along the outer periphery of the wafer, an interference type film thickness meter for measuring the thickness of a resist film spun out to the resist receiving plate, and modifying means for changing the revolution number of the support plate on the basis of a result of measurement by the film thickness meter such that a desired resist film thickness can be obtained.

Abstract: A filter apparatus having a filter element and a stop valve, both incorporated in a body thereof. By means of an engagement, the stop valve is coupled with a cap which is fitted to a body of the filter apparatus by thread-engagement. When the cap is removed from the body for replacement of the filter element, the stop valve rotates together with the cap to close an inlet port of the filter apparatus. On the other hand, when the cap is fitted to the filter apparatus, the stop valve directs the fluid into the filter apparatus since an opening provided in the stop valve coincides with the inlet port because of rotation of the stop valve.