JP2000240813A - Flow control damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the flow controllability of damper and reduce abrasion of blades due to powder contained in gas. SOLUTION: At least a pair of two blades 13 and 14 is mounted symmetrically with each other in a duct 10. An inclination of blades 13 and 14 is set at an angle of about 45 deg. or less with respect to a duct center line when fully closed, and an angle of blades 13 and 14 is set at an angle of about 45 deg. or less with respect to a gas flow. Accordingly high controllability is obtained across all ranges, from a fully closed condition to a fully opened condition, collision angles of gas on the blades 13 and 14 are made smaller, the deflection of gas flow is controlled, and abrasion of blade tips is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control damper provided in an exhaust duct or the like for adjusting a gas flow rate or the like.

[0002]

2. Description of the Related Art Ducts for supplying and exhausting air are provided in equipment such as a boiler, and a damper is provided in the middle of the duct to adjust the flow rate of gas flowing through the duct.

[0003] A conventional damper will be described with reference to FIG.

[0004] A damper 2 is provided at a required position of the duct 1.
A required number of blades 3, 4 in FIG. 3 are rotatably provided on the damper 2, and the blades 3 and 4 rotate synchronously in the same direction at a rotation angle of about 90 °. One wing 3 opens and closes the upper half of the duct 1, and the other wing 4 opens and closes the lower half of the duct 1.

A state in which the duct 1 is closed by the damper 2 is shown by a two-dot chain line in FIG. 3, and from this state, a state in which the wings 3 and 4 are partially opened by rotating the wings 3 and 4 in the counterclockwise direction is shown. , Indicated by solid lines. The flow rate adjustment characteristic of the conventional damper 2 shown in FIG. 3 is shown by a curve II in FIG.

[0006]

As can be seen from the curve II in FIG. 2, when the rotation angle of the blades 3 and 4 increases, the proportionality between the rotation angle and the flow rate (opening) is lost, and the controllability becomes extremely high. At a small rotation angle, the collision angle between the gas flow and the blade increases, and the collision between the gas and the blade becomes remarkable. For this reason, when the gas contains powder, such as in a pulverized coal boiler, wear of the blade tip due to collision between the gas and the blade becomes a problem.

[0007] Further, as shown in FIG. 3, gas drift occurs due to the blades 3 and 4, and the gas collides with the duct wall surface. For this reason, there was a problem that abrasion also occurred in the duct.

The present invention has been made in view of the above circumstances and aims to improve the controllability of the flow rate of a damper, reduce wear caused by powder contained in gas, and extend the life of the damper.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there are provided two ducts.
The present invention relates to a flow control damper in which at least one set of wings is provided symmetrically with respect to each other, and the inclination angle of the wings when fully closed is set to be approximately 45 ° or less with respect to the center line of the duct. Is related to a flow control damper with which the downstream end abuts when fully closed.
° or less, and the rotation angle of the wing is from 0 ° to a maximum of approximately 45 °, so high controllability is obtained in the entire range from fully closed to fully open, and the collision angle between the wing and gas is reduced. In addition, the deflection of the gas flow can be suppressed, and the wear of the blade tip and the duct can be suppressed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

The rotating shaft 1 is located at a vertically symmetric position of the duct 10.
1 and 12 are rotatably provided, and wings 13 and 14 are fixed to the rotating shafts 11 and 12, respectively. The wings 13 and 14 have a maximum thickness at a portion fixed to the rotating shafts 11 and 12, and have a flat rhombus shape in which the cross section gradually becomes thinner toward the tip.
The total length is such that the downstream ends of the wings 13 and 14 come into contact with each other and the upstream ends of the wings 13 and 14 come into contact with the upper surface and the lower surface of the duct 10 at the same time. The state is a fully closed state, and the angle between the wings 13 and 14 and the duct center line in the fully closed state is 30 °.

The rotating shafts 11 and 12 are connected to an opening / closing drive (not shown).
The wings 13, 14 are symmetrically rotated via 1, 12. The wings 13 and 14 are fully opened by being rotated 15 degrees from the fully closed state.

The flow rate adjustment characteristic of the damper in the present embodiment is shown by a curve I in FIG. In the present embodiment, the rotation angle from fully closed to fully open is small, and a linear relationship can be maintained between the rotation angle and the flow rate, that is, the opening (opening area), and high controllability is maintained over the full opening. Can be maintained.

Further, since the downstream ends of the blades 13 and 14 rotate so as to approach and separate from each other, there is no deflection of the flow. or,
The blades 13 and 14 have the maximum inclination with respect to the duct center line in the fully closed state, the maximum inclination is 30 °, the collision angle between the flow and the blade is small even when the opening is small, and the gas flow velocity is high. Wear of the tip can be suppressed.

The angle between the wings 13, 14 and the center line of the duct when fully closed may be about 45 °. Further, needless to say, a plurality of sets of the blades 13 and 14 may be provided corresponding to the size of the duct.

[0016]

As described above, according to the present invention, high controllability can be obtained in the entire range from fully closed to fully open.
In addition, an excellent effect that the collision angle between the blade and the gas can be reduced, the deflection of the gas flow can be suppressed, and the wear of the blade tip can be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a main part showing an embodiment of the present invention.

FIG. 2 is a diagram showing a flow rate characteristic of a damper according to an embodiment of the present invention and a conventional example.

FIG. 3 is an explanatory view of a main part showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Duct 11 Rotation axis 12 Rotation axis 13 Blade 14 Blade

Claims (2)

[Claims] At least one set of two wings is provided symmetrically in a duct, and the angle of inclination of the wings when fully closed is approximately 45 ° or less with respect to the center line of the duct. And a flow control damper. 2. The flow control damper according to claim 1, wherein the blades of each set abut on the downstream end when fully closed.