Abstract: A large capacity HEPA filter is produced having a layered filter medium unitarily formed by an upstream non-woven fabric, which can remove 70 to 90% of 0.3 ?m particles, and a downstream non-woven fabric, which can remove 99.9% of 0.3 ?m particles or more. The layered filter medium is shaped as a mini pleat shape in a thickness direction and an entire shape in the thickness direction is a plurality of continuous Vs. Also, a dust collecting device having such a large capacity HEPA filter is produced and an air intake device for a gas turbine is provided with such a dust collecting device.

Abstract: A large capacity HEPA filter is produced in which a layered filter medium unitarily formed by an upstream non-woven fabric which can remove 70 to 90% of 0.3 &mgr;m particle and a downstream non-woven fabric which can remove 99.9% of 0.3 &mgr;m particle or more is provided and a shape of a layered filter medium is a minipleat shape in a thickness direction and an entire shape in the thickness direction is a plurality of continuous Vs. Also, a dust collecting device having such a large capacity HEPA filter is produced. An air intake device for a gas turbine is provided with such a dust collecting device.

Abstract: A gas turbine suction air filter is provided wherein, despite a large capacity, dust is easily removed by an ultrasonic washer. A gas turbine suction air filter (1) has a box-like frame member (3) and a filter cloth (5) contained in the frame member (3). The frame member (3) is made of a metal material, preferably a stainless steel. The filter cloth (5) is formed having many pleats so that many folded faces (7) are formed. No intervening member is provided between adjacent folded faces (7, 7), with only a space being arranged there. The filter cloth (5) is a non-woven fabric of a synthetic resin fiber, preferably a polypropylene fiber. While this filter (1) has a large capacity, an ultrasonic wave reaches the entire filter cloth (5) when the filter (1) is washed by an ultrasonic washer.

Abstract: A gas turbine suction air filter is provided wherein, despite a large capacity, dust is easily removed by an ultrasonic washer. A gas turbine suction air filter (1) comprises a box-like frame member (3) and a filter cloth (5) contained in the frame member (3). The frame member (3) is made of a metal material, preferably a stainless steel. The filter cloth (5) is formed having many pleats so that many folded faces (7) are formed. Between adjacent folded faces (7, 7), no intervening member is provided with only a space being arranged there. The filter cloth (5) is a non-woven fabric of a synthetic resin fiber, preferably a polypropylene fiber. While this filter (1) has a large capacity, the ultrasonic wave reaches to the entire filter cloth (5) when the filter (1) is washed by an ultrasonic washer.