Abstract: A hollow fiber membrane module having a structure, in which raw water is supplied into a filtration chamber containing a hollow fiber membrane and surrounded by a first sealing body having the open ends of the numerous hollow fiber membranes constituting the hollow fiber membrane bundle, a cylindrical case and a second sealing means, through a raw water supply port formed in the cylindrical case at a position near the second sealing body, and in which the drain of backwashing is discharged through a drain port formed in the second sealing body.

Abstract: A heat treatment apparatus which comprises a treatment chamber formed with heat insulating walls, a graphite heater installed in the treatment chamber, a gas supply port supplying non-oxidizing gas to the chamber and an exhaust port for carrying gas out of the chamber. At least a part of the inner side of the heat insulating walls is made of graphite group material of bulk density of not less than 0.3 g/cm.sup.3. The ratio of the outer surface area of the graphite heater (Ah) to the surface area of the chamber-facing side of the heat insulating walls (Ai), Ah/Ai is within the range of 0.1-0.4, and the relationship between the surface area of the graphite group material (Ar) and (Ah) is Ar>Ah. By this structure, the temperature of the heater to be set for heat treatment of workpieces can be decreased, and the life spans of the heater and the heat insulating walls can be increased.