GROUND FLARE
Provided is a ground flare in which a low-frequency vibration generated from a ground flare tower, such as a chimney, is properly adjusted to suppress it below a fixture-vibration generation limit, thereby preventing surrounding objects from resonating and vibrating. In a ground flare that burns a flammable exhaust gas with a burner at the lower end of a chimney, in which the lower end of the chimney and the periphery of the burner are surrounded by a windbreak, the low-frequency-noise sound pressure level of a ground flare tower composed of the chimney and the windbreak is reduced by selecting at least one of changing a natural frequency generated from the ground flare tower, using multiple ground flare towers, and installing a low-frequency-vibration absorber in the ground flare tower.
1 . A ground flare that burns a flammable exhaust gas with a burner at the lower end of a chimney, the lower end of the chimney and the periphery of the burner being surrounded by a windbreak, wherein
the low-frequency-noise sound pressure level of a ground flare tower composed of the chimney and the windbreak is reduced by selecting at least one of changing a natural frequency generated from the ground flare tower, using multiple ground flare towers, and installing a low-frequency-vibration absorber in the ground flare tower.
2 . The ground flare according to claim 1 , wherein the change of the natural frequency generated from the ground flare tower is achieved by providing a windbreak opening in part of the windbreak and closing the windbreak opening with a non-wall sheet against a low-frequency sound.
3 . The ground flare according to claim 2 , wherein the windbreak opening has a circumferential opening ratio of 50% or higher and a height opening ratio of 70% or higher.
4 . The ground flare according to claim 2 , wherein the sheet surface density of the non-wall sheet is selected depending on a dominant frequency in front of the windbreak opening.
5 . The ground flare according to claim 1 , wherein the change of the natural frequency generated from the ground flare tower is achieved by providing a chimney opening in part of the chimney.
6 . The ground flare according to claim 5 , wherein the chimney opening is a lateral opening provided within a range from 90° to 360° in a circumferential direction.
7 . The ground flare according to claim 6 , wherein the heightwise position of the lateral opening is disposed at a portion corresponding to an antinode of a sound pressure mode generated from a resonant frequency.
8 . The ground flare according to claim 6 , wherein the opening area ratio of the lateral opening is set to 25% or higher.
9 . The ground flare according to claim 6 , wherein the lateral opening is provided at a plurality of positions of the chimney in the heightwise direction.
10 . The ground flare according to claim 5 , wherein the chimney opening is one or a plurality of vertical openings that is open in the heightwise direction of the chimney.
11 . The ground flare according to claim 5 , wherein an opening concealing member is disposed outside the chimney opening, with a gap therebetween, and the area of a gap formed between the gap and the chimney is set larger than the opening area of the chimney opening.
12 . The ground flare according to claim 1 , wherein the change of the natural frequency generated from the ground flare tower is achieved by setting the burner position ç′ of the burner, which is found using [Formula 1], within a range of 2.2 to 3.4 from the inlet of the windbreak with respect to the entire length of a guide including the chimney and the windbreak.
13 . The ground flare according to claim 12 , wherein the entire length of the guide is extended by increasing the length of the chimney and/or the windbreak.
14 . The ground flare according to claim 1 , wherein the multiple ground flare towers are achieved by combining towers having different dominant frequencies.
15 . The ground flare according to claim 1 , wherein the installation of the low-frequency-vibration absorber in the ground flare tower is achieved by hanging a large number of sheets in a noise guide formed between the windbreak and the chimney at an angle of inclination with respect to a vertical direction.
16 . The ground flare according to claim 15 , wherein the angle of inclination is set in a range from 10° to 60°.
17 . The ground flare according to claim 15 , wherein the sheet is bent at a plurality of locations.
18 . The ground flare according to claim 15 , wherein a top plate is installed above the inlet of the noise guide.
19 . The ground flare according to claim 7 , wherein the opening area ratio of the lateral opening is set to 25% or higher.
20 . The ground flare according to claim 19 , wherein an opening concealing member is disposed outside the chimney opening, with a gap there between, and the area of a gap formed between the gap and the chimney is set larger than the opening area of the chimney opening.