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(11) | EP 0 937 872 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A conduit system for the exhaust gases in a multi combustion engine system and a damper for it |
| (57) The invention relates to a conduit system for the exhaust gases in a multi combustion
engine system, in which conduit system the exhaust gas conduits (11) of two or more
combustion engine systems (10) are attached onto a common head conduit (13), and each
exhaust gas conduit (11) includes a damper (14) which also functions as an overpressure
guard in order to protect the system from a sudden pressure shock. The axle (15) of
the damper (14) is arranged eccentrically in relation to the blade (17) and is set
to open due to overpressure. |
[0001] The invention relates to a conduit system for the exhaust gases in a multi combustion engine system, in which conduit system the exhaust gas conduits of two or more combustion engine systems are attached onto a common head conduit, and each exhaust gas conduit includes a damper and an overpressure guard in order to protect the system from a sudden pressure shock.
[0002] The invention also relates to a damper, which includes a frame attached to the exhaust gas conduit and a blade that is fitted onto the frame and that turns on the axle, a sealing edge that is fitted between the blade and the frame and operating devices for using the damper.
[0003] Combustion engine systems are often used in power plants and stand-by power plants for producing electricity. The combustion engine systems are usually either diesel engines or gas turbines, but also boiler systems may be used. Due to the variations in the need for electricity and in order to enhance the reliability of the supply of electricity, two or more combustion engine systems are often used together. From the combustion engine systems, the exhaust gases are lead through conduits into a common combustion gas purification unit. Generally the conduits are connected together soon after the combustion engine systems so as to form one head conduit, which finally ends in a smokestack after the common handling devices. Because it may be necessary to service each of the combustion engine systems while the others are still functioning, each conduit must have a damper, situated before the point of connection of the conduits. This prevents the spreading of the exhaust gases into the combustion engine system that has been stopped. In order to achieve a 100% sealing, shutoff gas needs to be used. Hereby the blade of the damper includes two sealing edges, in between which shutoff gas, normally air, is fed.
[0004] In German patent publication DE 1214051, another system for preventing the spreading of the combustion gas into the machine that is stopped has been presented. The system does not allow separate servicing of the machines, because there is no damper in the outlet conduits.
[0005] For safety reasons, each exhaust gas conduit has an overpressure guard, usually a breaking diaphragm, which breaks if the machine is, for instance, turned on whilst the damper is closed. The diaphragm precaution that is broken by the effect of an abnormal pressure wave prevents the pressure from further rising in the conduit, whereby the pressure wave does not break the conduit or the damper.
[0006] There needs to be a separate overpressure guard in each conduit, which adds on to the costs of setting up a power plant. The overpressure guard, although seldom used, still needs constant monitoring and servicing in order to maintain its reliability. In addition, the acquisition and installation costs of a new precautionary unit are great.
[0007] The object of the invention is to achieve a simpler, more easily regulated conduit system with less components for the exhaust gases in a multi combustion engine system, and a damper for it. The characteristic features of this invention are presented in the adjoining patent claims. The structure of the damper according to the invention makes possible the normal discharging of the pressure wave into the outlet conduit, because the damper is set to open from the effect of a pressure wave. In addition, the opening pressure can be easily regulated. The damper not only includes the components that are required by the overpressure guard, but the damper also functions as an overpressure guard. The combination structure does not, however, adversely affect the tightness of the damper.
[0008] In the following, the invention is presented in detail, referring to the adjoining drawings that present one application of the invention, in which
- Fig 1
- presents schematically the exhaust gas system of two combustion engine systems,
- Fig 2
- presents a damper according to the invention as seen from behind,
- Fig 3
- presents a partial enlargement of a slightly open damper from the angle of the axle penetration,
- Fig 4
- presents the bearing of the blade to the frame, cut from in between the axle and seen from above,
- Fig 5
- presents the connection between the operating device and the axle of the blade,
- Fig 6
- presents a slightly open damper as seen at the front and from an oblique angle
[0009] As is seen in figure 1, neither of the exhaust gas conduits 11 has a separate overpressure damper. According to the invention, damper 14 has been fitted to open due an overpressure that goes in the direction of the normal stream. Hereby damper 14 also functions as an overpressure damper, replacing the separate overpressure damper. Structurally this has been achieved by arranging the axle 15 onto frame 16 on the side of the middle line 38 of the cross-section of the frame, which line goes in the direction of axle 15. Axle 15 has been arranged on the side of said middle line 38 at a distance that corresponds to 5 - 15 % of the diameter of the damper 14. Due to the installation of the lopsided blade 17, part of the force created by the pressure wave onto blade 17 strives to open damper 14. The pressure wave is almost only formed when starting combustion engine system 10. What is meant by overpressure here is an overpressure that is formed by a pressure wave inside the exhaust gas conduit 11 in the above presented situation or otherwise. The damper is regulated in such a way that it starts to open once the pressure in the conduit rises above a certain limit. In figure 2, damper 14 is presented from behind, i.e. as it is seen from the opposite side of the combustion engine system 10.
[0010] The frame 16 that belongs to damper 14 is essentially round. The frame and at the same time the whole damper can also be of a different shape, e.g. rectangular or polygonal. The bearing blocks 18 of axle 15 have been supported onto frame 16 by elevation pipes 19. The operating devices of damper 14 include device 20 in order to open the damper and pressing devices in order to close it and to keep it closed. By means of the pressing devices, damper 14 has been fitted to close automatically. Here the pressing devices are formed out of even-sided lever mechanisms 21 that have an effect on axle 15, and weights 23 that have been attached to these mechanisms with an appropriate allowance for adjustment. Depending on the application, the weights 23 can be changed, whereby the opening pressure of damper 14 can be set as desired. The fine-tuning is done by the allowance for adjustment. It is also possible to use other types of pressing devices, but a gravitational pressing device is profitable because it does not require a separate operating device. Further, with automatics it is possible to achieve the effect that the damper closes when the combustion engine system stops for some reason, whereby the exhaust gases of the other combustion engine systems will not be able to spread.
[0011] When the damper opens, a normal-sized outlet is opened to the pressure wave, whereby it is unlikely that the structures will break. When the combustion engine system that has been started by mistake is again shut down, the damper automatically closes. Hereby the functional situation of the power plant machinery returns to normal without any stoppages of work.
[0012] Figure 2, 3 and 4 show the segments 24 that even the asymmetry of blade 17, which are situated by the penetrations of axle 15 in frame 16. The opening of damper 14 becomes more sensitive when the axle is moved more to the side of the middle line, but then larger segments are needed. The blade 17 itself is mainly formed out of a cover structure, which is formed with the help of two metal plates 25 and 25'. Blade 17 is tightened with metal plates 25 and 25' onto groove 26 that is in two parts in the same relation and which is situated in frame 16, whereby a space limited by two sealing edges 27 and 27' is formed onto the edges of blade 17. Shutoff gas is lead into this space in order to tighten the damper. The shutoff gas, which is usually pressurised air, is lead from the shutoff gas conduit 28 that goes around the outer circle of frame 16, through shutoff gas connections 29, in between the sealing edges 27 and 27'. The number of shutoff gas connections 29 varies in different applications.
[0013] Damper 14 and damper 30 that belongs to the shutoff gas conduit 28 have been fitted together by lever 31 and axle 31' in such a manner that one is closed when the other one is open. Axle 31' further uses the power switch of blower 48 that produces the shutoff gas.
[0014] Figure 4 presents the penetration of axle 15 and the tightening of blade 17 to groove 26 in more detail. In figure 4, segment 24 and the components that are on its left side have been cut from the plane that is above bushing 37. The rest of the structure has been cut from the middle line of axle 15. Axle 15 has been mounted in bearings from both ends to bearing block 18, which is attached to frame 16 by elevation pipe 19. In connection with bearing 32, there are also gaskets, so elevation pipe 19 is tight from its outer edge. Axle 15 is taken, through frame 16 and segment 24 that belongs to it, and inside blade 17, onto the other side of frame 16, in which there is a corresponding bearing 32. By segment 24, there is also a bushing 37 attached to axle 15, which bushing reaches close to frame 16. The metal plates 25 and 25' of blade 17 correspond to groove 26, whereby the situation described in connection with figure 3 arises. Flexible, metallic tightening plates 34 are further attached by bolts 33 onto metal plates 25 and 25', which tightening plates correspond to the equivalent parts 35 that are attached to groove 26. Hereby four sealing edges are formed in practice.
[0015] Elsewhere except by segment 24, the shutoff gas connections 29 are arranged to frame 16. By segment 24, on the contrary, the connections 29 are in segment 24. The shutoff gas is led to connections 29 through shutoff gas conduit 28 that covers the whole circle of frame 16. By elevation pipe 19 the said conduit 28 is cut off, but it is welded onto elevation pipe 19. Elevation pipe 19 further includes one or more holes 36 in order to lead the shutoff gas first to elevation pipe 19 and then, from in between axle 15 and frame 16, inside segment 24. From segment 24, the shutoff gas is lead through holes 39 of the penetration of bushing 37 on both sides of blade 17. The structure prevents the exhaust gas from spreading through the penetration of axle 15 from one side to the other of damper 14, hereby improving the tightness of the damper.
[0016] The operating device has been taken off in figure 5. It turns the operating axle 41. This has not been directly attached to axle 15 of the blade, to which axle a lever bushing 15' that can well be seen in the figure has been fixedly attached. This bushing turns lever 31 of the shutoff gas device. The shaft 23' of lever mechanism 21 of the pressing devices has further been welded onto this lever bushing 15', at the end of which shaft a weight 23 has been fixed (not shown.)
[0017] From the point of view of the invention, it is essential that the operating axle 41 is connected to axle 15 of the blade with the help of connection 40, which allows axle 15 to turn from its closed position against the pressing device in the event of a pressure shock, whereby the damper opens in order to remove the overpressure. Connection 40 includes a symmetrical functioning lever 42 and cams 43 that have been welded onto it. These have been set against lever 23' so that they together transmit a pure rotational moment to lever 23' and from it to axle 15 of the blade, when the damper is opened. They transmit no moment in the other direction, whereby lever 23' is able to turn to the open-direction from the position presented in the figure, and is able to come loose from cams 43.
[0018] In figure 6, the operating device is opening the damper. Connection 40 is operational and operating lever 42 transmits a moment through its cams 43 onto shaft 23'.
[0019] The damper according to the invention functions mainly as a damper, but where necessary also as an overpressure damper. The damper will open due to an overpressure even though the operating devices are out of order. Further, the number of the components needed does not go up much when compared with a mere damper.
1. A conduit system for the exhaust gases in a multi combustion engine system, in which
conduit system the exhaust gas conduits (11) of two or more combustion engine systems
(10) are attached onto a common head conduit (13), and each exhaust gas conduit (11)
includes a damper (14) and an overpressure guard in order to protect the system from
a sudden pressure shock, characterized in that each damper (14) is set to open due to an overpressure that goes in the direction
of the normal stream and is set at the same time to function as an overpressure damper
thereby replacing a separate overpressure guard.
2. A damper, which includes a frame (16) attached to the exhaust gas conduit (11) and
a blade (17) that is fitted onto the frame (16) and that turns on the axle (15), a
sealing edge (27, 27') that is fitted between the blade (17) and the frame (16) and
operating devices for using the damper (14), characterized in that the axle (15) has been arranged onto frame (16) on the side of the middle
line (38) of the cross-section of the frame (16), which line goes in the direction
of axle 15, so that the damper (14) is set to open due to an overpressure that goes
in the direction of the normal stream and is set at the same time to function as an
overpressure damper thereby replacing a separate overpressure guard.
3. Damper according to patent claim 2, characterized in that the axle (15) has been arranged on the side of said middle line (38) at a
distance that corresponds to 5 - 15 % of the diameter of the damper (14).
4. Damper according to patent claim 2 or 3, characterized in that pressing devices (21, 23) have been attached to the axle (15) in order to
press the damper into its closed position, and the operating devices include a turning
device (20) and a one-directional connection (40) that uses the axle (15) in order
to open the damper (14), in which the connection (40) is fitted to allow the turning
of the axle (15) onto the open-position and thereby to allow the damper to open due
to a pressure shock against the pressing devices.
5. Damper according to patent claim 4, characterized in that the pressing devices include a lever mechanism (21) that is fixedly attached
to the axle (15) and weights (23) that use it.
6. Damper according to one of patent claims 2 - 5, characterized in that the damper (14) is essentially round and there are segments (24) by the penetrations
of the axle (15) on the inside of the frame (16).
7. Damper according to one of patent claims 2 - 6, characterized in that the blade (17) of the damper includes two sealing edges (27, 27') and devices
for leading the shutoff gas in between these.
8. Damper according to patent claim 7, characterized in that holes (39) have been arranged in between the axle (15) and the frame (16)
in order to lead the shutoff gas from the shutoff gas conduit (28) through the penetration
of the axle (15) onto both sides of the blade (17).