Diverter damper

Abstract

A diverter damper for controlling a gas flow in a gas duct of large cross section. The diverter damper includes a housing having an inlet and two outlets, a pivotable flap which in a first extreme position closes a first outlet and in a second extreme position closes a second outlet. The damper further includes a drive shaft connected to the pivotable flap, wherein the drive shaft extends at least partly between two opposite housing walls and through at least one of the two opposite housing walls, and at least one actuator mechanism that is located outside the housing near or against the at least one housing wall through which the drive shaft extends. The actuator mechanism includes at least one cylinder piston unit connected to the drive shaft for pivoting the flap into one of the extreme positions or into a position between the extreme positions.

Claims

1. A diverter damper for controlling a gas flow in a gas duct of large cross section, said diverter damper comprising: a housing having an inlet and first and second outlets, a pivotable flap which in a first extreme position closes the first outlet and in a second extreme position closes the second outlet, a drive shaft connected to the pivotable flap, wherein the drive shaft extends through two opposite housing walls of the housing and is rotatable about an axis, at least one actuator mechanism that is located outside the housing near or against one of the two housing walls through which the drive shaft extends, wherein said actuator mechanism comprises two cylinder piston units connected to said drive shaft for pivoting the flap into one of the extreme positions or into a position between the extreme positions, wherein said drive shaft comprises two hollow actuator pipe end parts, each actuator pipe end part extends through a respective one of the housing walls such that said actuator pipe end parts are located both inside the housing where said actuator pipe end parts are connected to the flap and outside the housing, wherein outside the housing at least one of the actuator pipe end parts comprise connection flanges for providing a connection between the actuator pipe end part and a first end of each of the two cylinder piston units, which connection flanges are in one-piece with the actuator pipe end part, wherein the connection flanges are provided on opposite sides of the actuator pipe end part and a frame, wherein the frame comprises two frame parts that are axially spaced from the connection flanges and wherein the frame is movable with respect to the housing and the connection flanges are movable with respect to the frame.

2. A diverter damper according to claim 1, wherein the actuator pipe end parts are substantially identically dimensioned and substantially identically hollow having a common virtual center axis.

3. A diverter damper according to claim 2, wherein the end parts of the actuator pipe are connected with each other by means of at least one middle actuator pipe section such that a single hollow actuator pipe with a substantially uniform diameter and uniform wall thickness is provided.

4. A diverter damper according to claim 1, wherein the actuator pipe end part inside the housing is connected to the flap by means of levers configured in an elbow construction.

5. A diverter damper according to claim 4, wherein each actuator pipe end part inside the housing is provided with a connector to connect the actuator end parts to one of the levers, wherein the connectors are formed in one-piece with the actuator pipe end part.

6. A diverter damper according to claim 4, wherein one of the levers is formed in one piece with the actuator pipe end part.

7. A diverter damper according to claim 1, wherein the flanges are pivotally mounted to the cylinder piston units for rotating the actuator pipe end parts.

8. A diverter damper according to claim 1, wherein each frame part is connected by a sleeve bearing to one of the actuator pipe end parts.

9. A diverter damper according to claim 1, wherein the two frame parts are connected to a cylinder barrel of the cylinder piston unit, which cylinder barrel is supported pivotally about a pivot axis by means of at least one external support.

10. A diverter damper according to claim 1, wherein the at least one hollow actuator pipe end part is provided at least partly with insulation located inside the hollow pipe end part.

11. A diverter damper according to claim 10, wherein the insulation has a shape having a diameter corresponding approximately to the inner diameter of the hollow pipe end part for in use blocking heat from the part of the hollow pipe end part located inside the housing to the part of the hollow pipe end part located outside the housing.

12. A diverter damper according to claim 1, wherein at least one of the housing walls through which said actuator pipe end parts extend comprises a smaller wall part which is manufactured as one whole with the drive shaft, which smaller wall part is connected on a building site to a larger wall of the at least one housing wall part.

13. A method for building the diverter damper according to claim 1, wherein at least one of the opposite housing walls comprises a smaller wall part, through which smaller wall part the actuator pipe end part extends, wherein the method comprises the step of welding each smaller wall part to a larger wall part of said housing wall for positioning the actuator mechanism including the actuator pipe end parts on a building site.

Description

(1) The invention will now be explained in more detail with reference to an exemplary embodiment shown in the appended figures, in which:

(2) FIG. 1 shows a schematic cross section of a diverter damper according to the invention,

(3) FIG. 2 shows a side view of a part of a diverter damper according to the invention shown in FIG. 1,

(4) FIG. 3 shows a cross section A1-A1 as identified in FIG. 2, of a actuator pipe end part of a diverter damper according to the invention.

(5) Like parts are indicated by the same numerals in the various figures.

(6) A diverter damper 1 shown in FIG. 1 includes a housing 3 having three conductor connections, i.e. an inlet 5 and two outlets 7, 9. FIG. 1 shows mainly features of a diverter damper according to the invention inside housing 3. These inlet 5 and outlets 7, 9 are in a build-up stage connected to gas ducts (not shown). It is also possible that in use one of the outlets 7, 9 will function as an inlet, such that inlet 5 will become an outlet. Outlets 7, 9 are provided with sealing means 11, 13 respectively. A flap 19 with respective sealing members 15, 17 is mounted in housing 3 for reciprocal pivoting movement through an angle of approximately 90 degrees about a shaft 20 defining a first pivot axis 21. Thus, flap 19 is pivotable around the first pivot axis 21 to a first extreme position in which first position flap 19 closes a first outlet 7 as shown by solid lines in FIG. 1 and from the first position the flap 19 is pivotable to a second extreme position closing the second outlet 9, partly shown in dashed lines in FIG. 1. In the extreme positions of the flap an outlet 7, 9 is blocked by means of the flap 19, sealing means 11, 13 and sealing members 15, 17.

(7) Flap 19 is moved between the extreme positions thereof by a drive shaft 25 defining an axis 27 by pivotable levers 29, 30 fixed to drive shaft 25. Levers 29, 30 are pivotable around a second and third pivot axes 31, 33. Rotation of drive shaft 25 in opposite directions about axis 27 will move lever 29 through an angle of rotation sufficient to cause lever 30 to move flap 19 between the two extreme positions thereof. In FIG. 1 the extreme positions are shown with solid lines and partly with dashed lines, see for example dashed levers which are indicated in FIG. 1 with an accent, see FIG. 1 levers 29 and 30. This configuration of levers 29, 30 connected to drive shaft 25 and flap 19 is known in the prior art and this configuration of levers is indicated as an elbow configuration of a diverter damper 1 of the toggle type. As this configuration is known by a person skilled in the art details of how this elbow configuration operates will be omitted in this description.

(8) In FIG. 2 a section of a housing wall 51 of housing 3 is shown, more in particular the outside of housing wall 51 is shown. Further, there is illustrated in FIG. 2 an actuator mechanism 55, located outside the housing 3, for reciprocal rotation of drive shaft 25 about axis 27 to achieve movement of flap member 19 between the two extreme positions thereof. A housing wall (not shown) opposite to housing wall 51 comprises also an actuator mechanism (not shown), which is identical to the actuator mechanism 55 shown in FIG. 2. In FIG. 3 a schematic cross section is shown across dashed line A1-A1 shown in FIG. 2. FIG. 3 shows drive shaft 25, part of the actuator mechanism 55 located outside the housing on a side facing the outside 51a of housing wall 51, and a part of drive shaft 25 located inside the housing facing the inside 51b of housing wall 51a, which part is connected (not shown in FIG. 3) to lever 29.

(9) The drive shaft 25 according to the present invention comprises two spaced apart, substantially identically dimensioned and substantially identically hollow actuator pipe end parts having a common virtual center axis 59 indicated with dashed line in FIG. 3. One of these actuator pipe end parts 60 is indicated in FIG. 3. Said actuator pipe end part 60 extends through the housing wall 51 such that the end part 60 is located both inside the housing 3 where each end part 60 is connected to one of the levers 27 and outside the housing 3 where each end part 60 is connected to the two cylinder piston units 61, 63. The other identical actuator pipe end part (not shown) extends through the opposite housing wall (not shown) of the diverter damper 1. The end parts of the actuator pipe 60 are connected with each other by means of at least one middle actuator pipe section 65 such that a single hollow actuator pipe 67 with a substantially uniform diameter and uniform wall thickness over its total longitudinal length is provided.

(10) Each actuator mechanism 51 comprises a hydraulic cylinder system with two cylinder piston units 61, 63, which two cylinder piston units 61, 63 are connected to the said drive shaft 25 for pivoting the flap 19 into one of the extreme positions or into a position between the extreme positions. The actuator mechanism comprises further a first frame 71 indicated in dashed lines in FIG. 3 and a second frame 73, wherein the second frame 73 comprises two second frame parts 73a,b between which the first frame 71 is located.

(11) The first frame 71 is composed of connection flanges 75, also known for a person skilled in the art as lever arms, which connection flanges 75 are in one-piece with the actuator pipe end parts 60 and the angle between the end part 60 and the connection flanges 75 is approximately 90 degrees. By means of the connection flanges 75, the first frame is pivotally mounted directly to a piston rod 77, 79 of the cylinder piston unit 61, 63 for rotating the end part 60 of the actuator pipe. Further, locking openings 72 are shown for locking the flap 19 in one of the extreme positions by means of a bar (not shown) during for example maintenance of the diverter damper 1.

(12) Each second frame part 73a, b is connected by means of one sleeve bearing 80 to the end part 60 of the actuator pipe 67. The two second frame parts 73a, b are connected to a cylinder barrel 81, 83 of the cylinder piston unit 61, 63, which cylinder barrels 81, 83 are supported pivotally about pivot axes 85, 87 by means of at least one external support 89, 91.

(13) In use for example in a gas turbine the delta temperature in time inside the housing 3 of the diverter damper 1 is very high. In a couple of minutes temperature rises inside the housing 3 of the diverter damper 1 from ambient temperature to 700 degrees or more. The drive shaft 25 is designed as an actuator pipe manufactured from only one material, having a constant cylindrical pipe-like shape and a constant material thickness. Due to these features of the actuator pipe, it will be heated up in a constant manner and will have a constant expanding behavior mainly in the longitudinal direction of the actuator pipe 67. In this way the thermal stress will be handled in a controllable manner. The longitudinal expanding of the actuator pipe 67 is compensated by means of the sleeve bearings 80 and/or by means of the cylinder piston unit 61, 63 pivotable about pivot axes 85, 87 by means of the external supports 89, 91. Therefore, the conventional thermal stress problems are no longer present in the drive shaft of the diverter damper 1 according to the present invention.

(14) Inside the housing each actuator pipe end part 60 is provided with connection means (not shown) to be connected to the lever 29, which connection means are preferably formed in one-piece with the actuator pipe end part 60. It is also possible that the lever 29 is formed in one piece with the actuator pipe end part 60.

(15) Further, the at least one hollow pipe end part is provided at least partly with an insulation 62 located inside the hollow pipe end part 60. The insulation 62 has a cylindrical shape having a diameter corresponding approximately to the inner diameter of the hollow pipe end part 60 for in use blocking heat from the part of the hollow pipe end part located inside the housing to the part of the hollow pipe end part located outside the housing. The insulation 62 is preferably positioned near the housing wall 51 and preferably has a length in the longitudinal direction of the drive shaft 25 corresponding to the thickness of the housing wall 51.

(16) The housing 3 comprises as is explained above the housing wall 51. In a preferred embodiment, see FIG. 2, the housing wall 51 comprises a larger wall part 93 and a smaller wall part 95 through which smaller wall part 95 the actuator pipe end parts 60 extend. The opposite housing wall 51 also has this smaller wall part (not shown) and larger wall part (not shown). The smaller wall part 95 is indicated by a combination of two dashed lines and one solid line (indicated by arrows in FIG. 3). The smaller wall part 95 is preferably connectable by welding to the larger wall part 93. In this way it is possible to prefabricate the smaller wall part 95 comprising the actuator mechanism 55 and actuator pipe 25 as a whole. Connecting this smaller part with the actuator mechanism 55 and actuator pipe 25 to the larger part can be done on site for positioning the actuator mechanism 55 and actuator pipe 25 in the diverter damper 1. This installation method reduces installation time up to 20%.

(17) In the drawings use of two hollow pipe end parts has been shown. It is however possible according to the invention to use only one hollow pipe end part. It is for example possible that the other end part of the drive shaft 25 does not extend through the opposite housing wall, but this other end part of the drive shaft 25 is bearing mounted to the inside of this housing wall.

(18) Although a toggle type diverter damper 1 is shown in the figures, it is also possible to use the hollow pipe end parts in a pivot type diverter damper (not shown).

(19) In addition, although two cylinder piston units 61, 63 are used in the preferred embodiment on each side of the housing for performing a pivoting movement of the flap, it is also possible to use only one cylinder piston unit on each side. In case of the above indicated drive shaft having only one end part according to the invention and the other end part of the drive shaft bearing mounted to the inside of this housing wall, the diverter damper may use only one cylinder piston unit for rotating the flap.