Dust collecting filter, dust collecting device, and air intake device for gas turbine

1. A dust collecting filter, comprising:

a layered filter medium unitarily formed by an upstream non-woven fabric configured to remove 70 to 90% of 0.3 μm particles and a downstream non-woven fabric configured to remove 99.9% of 0.3 μm particles or more, wherein a shape of the layered filter medium is a minipleat shape in a thickness direction, an entire shape of the layered filter medium in the thickness direction is a plurality of continuous V shapes, the upstream non-woven fabric is a filter medium having a thickness from 0.1 mm to 0.3 mm formed by fibers having a diameter from 0.3 μm to 15 μm, and the downstream non-woven fabric is a filter medium having a thickness from 0.1 mm to 0.3 mm formed by fibers having a diameter from 0.1 μm to 2 μm.

2. The dust collecting filter according to claim 1 , wherein the layered filter medium is contained in a filter frame having 600±20 mm in height, 600±20 mm in width, and 300±20 mm in length in size, and 5 to 7 V shapes are formed.

3. The dust collecting filter according to claim 1 , wherein a width of the minipleat shape is from 10 mm to 30 mm, and a pitch dimension of the minipleat shape is from 1.7 mm to 3.2 mm.

4. The dust collecting filter according to claim 1 , wherein the upstream non-woven fabric and the downstream non-woven fabric are non-woven fabrics formed by mixing a polyester fiber and a glass fiber.

5. The dust collecting filter according to claim 1 , wherein a flow rectifying section for introducing an air flow into a space formed between V-shaped wall sections comprises in an upstream V-shaped angular section formed by the layered filter medium.

6. The dust collecting filter according to claim 1 , wherein a separating member configured to separate an air flow which passes through a space between V-shaped wall sections is disposed in a downstream space which has a V-shape formed by the layered filter medium.

7. A dust collecting device comprising:

a dust collecting filter according to claim 1 .

8. The dust collecting device according to claim 7 , wherein the dust collecting device is disposed in an air intake mouth of a gas turbine so as to remove lithometeors contained in the air absorbed by the air intake mouth.

9. A dust collecting device for a gas turbine comprising the dust collecting device according to claim 7 .

10. A dust collecting filter comprising a layered filter medium, wherein the layered filter medium comprises a first non-woven fabric having relatively low particle removing efficiency and a second non-woven fabric having relatively high particle removing efficiency unitarily, the first non-woven fabric is a filter medium having a thickness from 0.1 mm to 0.3 mm formed by fibers having a diameter from 0.3 μm to 1.5 μm, and the second non-woven fabric is a filter medium having a thickness from 0.1 mm to 0.3 mm formed by fibers having a diameter from 0.1 μm to 2 μm.

11. The dust collecting filter according to claim 10 , wherein the first non-woven fabric is formed by mixing a first fiber having a relatively larger fiber diameter and a second fiber having a relatively smaller fiber diameter, the second non-woven fabric is formed by mixing a third fiber having a relatively larger fiber diameter and a fourth fiber having a relatively smaller fiber diameter, and a first fiber ratio is smaller than a second fiber ratio, the first fiber ratio being defined as a quotient of the diameter of the second fiber divided by the diameter of the first fiber and the second fiber ratio being defined as a quotient of the diameter of the fourth fiber divided by the diameter of the third fiber.

12. The dust collecting filter according to claim 11 , wherein the first fiber and the third fiber are polyester fibers, and the second fiber and the fourth fiber are glass fibers.

13. The dust collecting filter according to claim 10 , wherein the first non-woven fabric is configured to remove 70 to 90% of 0.3 μm particle, and the second non-woven fabric is configured to remove 99.9% of 0.3 μm particle or more.

14. The dust collecting filter according to claim 10 , further comprising:

a two-layer structure of the first non-woven fabric and the second non-woven fabric.

15. The dust collecting filter according to claim 10 , wherein a layered filter medium has a minipleat shape in a thickness direction.

16. The dust collecting filter according to claim 15 , wherein a width of the minipleat shape is from 10 mm to 30 mm, and a pitch dimension of the minipleat shape is from 1.7 mm to 3.2 mm.

17. The dust collecting filter according to claim 15 , wherein an entire shape of the layered filter medium in the thickness direction is a plurality of continuous V shapes.

18. The dust collecting filter according to claim 17 , wherein a flow rectifying section for introducing an air flow into a space formed between V-shaped wall sections comprises in an upstream V-shaped angular section formed by the layered filter medium.

19. The dust collecting filter according to claim 17 , wherein a separating member configured to separate an air flow which passes through a space between V-shaped wall sections is disposed in a downstream space which has a V-shape formed by the layered filter medium.

20. The dust collecting filter according to claim 17 , wherein the layered filter medium is contained in a filter frame having a dimensional ratio of height, width, and length of 2:2:1.

21. The dust collecting filter according to claim 20 , wherein 5 to 7 V-shapes wall sections are formed in the layered filter medium.