Nippondenso Co., Ltd.

Naohiko Kondo

Yuji Ito

Takatoshi Iwase

Tadahiko Shibata

Masahiko Sakai

Yuuji Ito

Harukazu Matuyama

Ikuo Mochizuki

Yoshiaki Miyagawa

Mineo Hanai

Yukio Ota

A ring-shaped corrugated filter element blank having radially alternate peak and valley folds is placed on a first mold having as many first concentric projections as the number of the peak folds of the ring-shaped blank and as many first concentric grooves as the number of the valley folds of the ring-shaped blank, with the peak folds fitted respectively over the first projections and the valley folds fitted respectively in the first grooves. Then, the ring-shaped blank is pressed between the first mold and a second mold, the second mold having second projections lying along concentric lines fitting respectively in the first grooves with the valley folds received therein, and second concentric grooves receiving respectively the first projections with the peak folds fitted thereover. The ring-shaped blank is heated while it is being pressed between the first and second molds, thereby forming a ring-shaped filter element. Thereafter, the ring-shaped filter element is cooled.

Method of and apparatus for forming filter element

A method and apparatus for making axial-flow filters wherein a sectorial-shaped sheet of filter material having corrugations therein parallel to the curved ends thereof is made from a flat sheet of filter material in the first step, and thereafter the corrugated sheet is made into an annulus to obtain the final product. In the first step, an edge portion of a flat sheet of filter material is attached to a sectorial-shaped mold, having a mold surface defined by curved ridges and valleys parallel to the curved ends of the mold, so that the sheet is slanted up away from the mold surface from the smaller curved end of the mold. Thereafter a set of curved forming blades is moved down toward the mold to engage the sheet and to fold it successively and consecutively across the ridges of the mold and beneath the edges of the blades into the valleys of the mold to corrugate the sheet. In the second step, the corrugated sheet thus produced is made into an annulus by using a contouring belt which embraces the larger convexly curved ends of the sheet and constricts the sheet into an annulus.

Method for making axial-flow filters and apparatus therefor

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Okazaki, Japan

Naohiko Kondo