Patent Application
20090255943
The invention refers to a device for collecting washing fluid from a jet power plant wash, with a collecting receptacle for washing fluid for arranging beneath the jet power plant and/or behind the exhaust end of the jet power plant.
Jet power plants of commercial subsonic transport aircraft are today widely predominantly so-called turbofan jet power plants. Such a turbofan power plant has a so-called core engine in which the actual combustion process of the kerosene is carried out. The core engine in a known manner has one or more compressor stages, a combustion chamber, and also one or more turbine stages in which the hot combustion gases yield some of their mechanical energy. This mechanical energy for one thing is required for driving the compressor stages, and for another thing a so-called turbofan, which is arranged upstream, is driven by the core engine and as a rule has a significantly larger diameter than the core engine, and allows a considerable part of the air which flows through the power plant as a whole to bypass the core engine as so-called bypass airflow or secondary airflow. The turbofan makes up a significant part of the thrust power of the power plant via this bypass airflow, and in addition the high bypass airflow portion provides for a better environmental compatibility of the power plant, especially a better efficiency at subsonic speeds, and also an improved noise suppression of the hot exhaust gas flow of the core engine.
Jet power plants, during operation, are contaminated as a result of combustion residues of the core engine, and also as a result of air contaminants which are drawn in with the combustion or bypass air, such as dust, insects, saline fog, or other environmental contaminants. These contaminants especially also form a coating on the rotor blades and/or stator blades of the compressor of the core engine, which impairs the surface quality and, as a result, ultimately the thermodynamic efficiency of the power plant.
For removing the contaminants, jet power plants are cleaned. It is known from WO 2005/077554 A1 to arrange a multiplicity of cleaning nozzles upstream of the fan of a turbofan power plant for this purpose in order to thus clean the fan and the core engine.
The contaminated cleaning fluid as a rule is collected. For this purpose, it is known for example from U.S. Pat. No. 7,297,260 B2 to arrange behind the propulsive nozzle of a jet power plant a fluid separator which separates out the fluid portion of the aerosol which issues from the propulsive nozzle. In addition, a drip tray is arranged over a wide area beneath the jet power plant in order to collect cleaning fluid which drains out of the cowling.
The invention is based on the object of creating a device for collecting washing fluid of the type referred to in the introduction, which is inexpensive and simple and convenient to handle.
According to the invention, the following features are provided:
First of all, some terms which are used within the scope of the invention are to be explained.
With a device according to the invention, washing fluid from a jet power plant wash is to be collected. During such a jet power plant wash, as a rule finely distributed fluid (preferably water, which is mixed with cleaning agents if necessary) is sprayed under increased pressure through the front air intake into the jet power plant, especially into the so-called core engine. A suitable device is described for example in EP 7 005 446.5. A part of this cleaning fluid discharges again as aerosol from the rear propulsive nozzle of the core engine of the jet power plant. Another part (as a rule the larger part of typically about 70%) of the cleaning fluid is first of all separated out inside the jet power plant, runs downwards, and drains out again for example through openings in the cowling of the jet power plant, out of the rear opening of the cowling, out of the secondary airflow exit, or out of the propulsive nozzle of the core engine. Since this fluid may be contaminated with impurities, it should be collected.
The term “jet power plants”, in the context of the invention, refers to any airplane power plants which include a gas turbine. They may also possibly be turboprop power plants.
The collecting receptacle according to the invention for washing fluid is designed for collecting draining-out washing fluid, and also for receiving an aerosol, which falls on account of gravity force, behind the propulsive nozzle of the power plant. The collecting receptacle is therefore essentially open on its side which points upwards in the in-use state, or has suitable collecting surfaces.
The collecting receptacle is provided for arranging beneath the jet power plant and/or behind the exhaust end of the jet power plant. The term “arranging beneath the jet power plant” is to be functionally understood and relates to an arrangement of the collecting receptacle which during a cleaning of the respective jet power plant completely collects, or largely collects, washing fluid which drains out.
An arrangement behind the exhaust end of the jet power plant, especially behind the exhaust end of the propulsive nozzle, allows collecting of the falling fluid aerosol which issues from the propulsive nozzle.
According to the invention, provision is made for the collecting receptacle to have at least two interconnectable collecting receptacle modules. In the in-use state of the device, these collecting receptacle modules are detachably interconnected to form a collecting receptacle. The modular construction of the collecting receptacle enables simple and space-saving transporting and storing of the collecting receptacle. In the in-use state, two or more (preferably 3 to 5, especially preferably 4) modules can be detachably interconnected to form a collecting receptacle which is arranged beneath and behind the jet power plant which is to be cleaned.
A jet power plant may have an axial length of about for example 5 m from the air intake to the exhaust of the propulsive nozzle. Washing fluid which drains out should preferably be collected over the entire length of the jet power plant during the cleaning process. In addition, the collecting receptacle should reach by about 2 to 4 m behind the exhaust end of the jet power plant in order to collect at least a large part of the aerosol which issues from the gas nozzle. The overall length of a collecting receptacle according to the invention can therefore be for example 7 to 10 m, and preferably 8 or 9 m. Another rule of thumb for the dimensioning of the overall length is the axial length of the jet power plant which is to be cleaned, plus a length of 2 to 6 m, more preferably 2 to 5 or 2 to 4 m.
The term “fixture for positioning the collecting receptacle beneath the jet power plant and/or behind the exhaust end of the jet power plant” refers to any device which is suitable for setting and maintaining a defined position of the collecting receptacle relative to the jet power plant which is to be cleaned. The collecting receptacle can be positioned without physical connection to the jet power plant which is to be cleaned, for example by maneuvering a suitable trolley beneath the power plant which is to be cleaned, wherein the trolley carries the collecting receptacle. Within the scope of the invention, however, it is preferred that the collecting receptacle is physically attached to parts of the power plant which is to be cleaned and is supported by this, as will be explained in more detail below.
The invention is based on the surprising knowledge that for largely complete collecting of the washing fluid when cleaning a jet power plant, the complex and costly separating device, which is assumed necessary in the prior art (U.S. Pat. No. 7,297,260 B2), for separating out the fluid portion from the aerosol which issues from the propulsive nozzle, is not necessary. The invention has realized that during a cleaning process the fluid portion of the aerosol has already fallen due to gravity force a few meters behind the exhaust of the propulsive nozzle to such an extent that it is collected by the collecting receptacle according to the invention. As already described above, for this purpose the collecting receptacle extends preferably by the said distance in the axial direction behind the exhaust end of the jet power plant.
A further aspect of the invention is the modular construction of the collecting receptacle. Since a typical overall length of a collecting receptacle according to the invention is about 8 to 9 m in the in-use state, such a receptacle as a whole is costly in handling during transportation and storage. The modular construction according to the invention enables a simpler and space-saving handling during transportation and storage.
The collecting receptacle is preferably formed in a longitudinally extended manner in the direction of view from above. This means that in the in-use state its longitudinal extent, as seen horizontally from above, with which it is arranged in the longitudinal axis of the jet power plant beneath this power plant, is considerably greater than its width perpendicularly to this longitudinal axis. The said factor is preferably 3 to 20, more preferably 5 to 15, and more preferably 6 to 12. Preferred lengths of the collecting receptacle have already been referred to above, preferred ranges for the width being 0.5 to 3 m, more preferably 0.6 to 2 m, more preferably 0.7 to 1.5 m, and more preferably 0.8 to 1.2 m.
The invention has realized that such a comparatively narrow collecting receptacle is adequate on the one hand to collect the largest part of the washing fluid which drains out of the jet power plant since this discharges essentially at the lowest points of the power plant. On the other hand, however, the largest part of the aerosol which issues from the propulsive nozzle is also collected since this aerosol is not widely distributed and therefore is deposited only to an insignificant degree near to the collecting receptacle. According to the invention, about 90% of the washing fluid which is introduced can be collected. It is understood that this portion depends significantly upon the environmental conditions which prevail during the washing process. At high outside temperatures, and when using a water-based washing fluid, a considerably larger part of the finely distributed water droplets is perhaps evaporated and cannot be collected.
Within the scope of the invention, it is preferred if the collecting receptacle has a weight which is as low as possible. For a weight-saving construction, it can be advantageous that each collecting receptacle module has a frame which imparts structural strength to it. Such a frame can be built from plastic or metal profiles. Fiber-reinforced plastics or light metals such as aluminum or aluminum alloys, are preferred for the material of the frame. The frame sections can be interconnected in a fixed manner, for example welded, but they can also be detachably interconnected so that the frame is collapsible.
The frame preferably supports a flexible receptacle sheeting which is designed for collecting the washing fluid. The actual receptacle is therefore formed by means of this flexible receptacle sheeting. This embodiment of the invention enables a particularly lightweight type of construction since the receptacle sheeting has a low weight per unit area and the overall structural strength of the collecting receptacle is ensured by means of the similarly lightweight frame. As receptacle sheeting, a plastic sheeting which is known in the prior art is preferably used, which is sufficiently stable and tear-resistant for the intended application and has an adequate resistance to constituents of the washing fluid. Depending upon the intended application, adequate UV-stability can also be of importance if power plant washes are conducted in the open.
The type of construction according to the invention enables a very lightweight construction of a collecting receptacle. A collecting receptacle, which is described in more detail in the exemplary embodiments below and consists of four modules which have an aluminum frame in each case, with a length in total of 8.40 m and a width of about 1 m, has an overall weight of only 23 kg. If a carbon fiber frame is used, this weight can be reduced to about 16 kg. Therefore, a weight of the collecting receptacle of under 50 kg, more preferably under 40 or under 30 kg, is preferred. Such light collecting receptacles can readily be fastened in the in-use state on the jet power plant and supported by this.
Within the scope of the invention, the receptacle sheeting can be detachably connected to the frame. In the case of a collapsible frame, for example frame profile sections can be pushed through supporting sections or supporting loops of the receptacle sheeting. In the case of a fixed frame, which is not collapsible within the limits of normal use of the device according to the invention, the receptacle sheeting can be looped for example over frame sections and welded to another sheeting section, or alternatively releasable connections such as hook-and-loop strips or the like can be provided.
Within the scope of the invention, it is preferred that each collecting receptacle module has at least one and preferably at least two or three fluid drains. In this way, it is to be ensured that during the washing process the largest part of the collected washing fluid can immediately be carried away by means of the drains and the weight of the collecting receptacle is only insignificantly increased as a result of the collected water. The said arrangement of a larger number of fluid drains achieves the effect of the largest part of the washing fluid being able to immediately drain away regardless of the accurate arrangement and alignment of each collecting receptacle module and not being able to accumulate at one point of a collecting receptacle module at which there is no drain.
Each collecting receptacle module can preferably form a top-open drip tray. In the assembled in-use state of the collecting receptacle, the edges of the trays adjoin each other, or abut against each other, and form an essentially large-area collecting receptacle.
According to an especially preferred variant of the invention, the collecting receptacle modules in a collapsed stowing state can be stacked one inside the other. For this purpose, provision can be made for each collecting receptacle module to have slightly different external dimensions in such a way that stacking one inside the other is possible. For example, in the case of a collecting receptacle consisting of four modules each module can be slightly shorter in the axial direction and slightly narrower transversely to this axial direction compared with the module adjoining on one side, so that this module can be inserted into the respective larger module and therefore stacked. In the assembled in-use state, the modules can be interconnected in a suitable way, for example the frames can be screwed to each other by means of simply manageable quick-release fasteners or wing nuts or the like, or can be connected in another way.
If the modules can be stacked one inside the other, as described above, the collecting receptacle can taper as a whole on account of the reducing width of each module in comparison to the preceding module. It is preferred, therefore, that the wider side of the collecting receptacle points rearwards in the in-use state in the gas flow direction of the jet power plant which is to be cleaned in order to form a collecting receptacle which is as wide as possible behind the jet exit of the power plant.
It is preferred that the collecting receptacle modules in the assembled in-use state are not in fluid communication with each other. This means that the fluid cannot flow from a collecting receptacle module directly into the adjoining module. This is possible for example by means of the described design of each collecting receptacle module as a separate drip tray. In this way, a one-sided weight loading of the collecting receptacle as a result of washing fluid accumulating in a corner or on one side is largely avoided. Alternatively, it is possible that the collecting receptacle modules in the in-use state form a large common fluid receptacle in which no fluid separation between the modules takes place.
If two collecting receptacle modules in the in-use state abut against each other, without there being a fluid connection between them, a diverting device can be provided, which diverts the washing fluid which impinges upon the region between two adjoining modules into at least one of these collecting receptacle modules. For example, it can be a sheeting section which is folded over the delimiting region of the adjoining modules and ensures that impinging fluid flows into one of the two collecting receptacle modules.
It is preferred that the device according to the invention is positioned in a desired manner beneath and/or behind the exhaust end of the jet power plant by means of fixtures for detachable mounting of the device on a jet power plant. These fixtures for detachable mounting for example can engage on the cowling, on the air intake of the turbofan and/or on the air exhaust of the propulsive nozzle of the jet power plant. For mounting on the cowling, for example vacuum suckers or suction cups can be provided. These can reliably support a collecting receptacle according to the invention on account of the low weight.
For mounting on the air intake of the turbofan and/or on the gas or air exhaust of the propulsive nozzle of the jet power plant, suitable hooking devices or clamping claws can be provided, which can preferably be covered with a soft material, such as plastic, so as not to damage the corresponding power plant parts.
The said positioning fixtures can preferably have devices for setting the inclination of the collecting receptacle relative to the horizontal, and also for the spacing of the collecting receptacle in the vertical relative to the jet power plant. A positioning which is as close as possible beneath the jet power plant has the advantage that during the washing process aerosol which issues from the propulsive nozzle is collected before it is widely distributed, for example on account of wind or the like, when falling to the ground.
An exemplary embodiment of the invention is described in the following text with reference to the drawings.
In the drawings:
The holders 6 of the receptacle sheeting trays 4 can be formed by the respective sheeting edge being turned over and being permanently connected to the inner side of the corresponding mating sheeting for example by welding, by adhesive fastening, or in another way. In this case, for mounting a collecting receptacle module the associated frame has to be collapsed and the longitudinal profiles 3 inserted into the associated holders 6 of the receptacle sheeting tray 4. The frame is then assembled, during which the longitudinal profiles 3 are connected to the corner profiles 2. In this form, the collecting receptacle modules can be mounted.
Alternatively, it is possible to releasably design the frame loops 6 of a receptacle sheeting tray, for example by means of hook-and-loop fasteners, slide fasteners, or the like.
Each receptacle sheeting tray, on one short edge, has a sheeting strip 7 which for example can be provided with a hook-and-loop strip at 8. This sheeting edge 7 bridges the region between two adjoining collecting receptacle modules in the mounted state of the collecting receptacle, and ensures that fluid which impinges there is diverted into one of the two collecting receptacle modules.
The corner profiles 2 of each frame have screwed connections, indicated by 9, by which two collecting receptacle modules can be screwed to each other on their short sides. Wing nuts or the like, which enable a simple assembly and disassembly without tools, are preferably used for the screw fastening. It is understood that other suitable connections can be used apart from screwed connections.
As is to be seen in
As is especially to be seen in
For carrying out a power plant wash, the device according to the invention is mounted and brought into the position which is shown in
After carrying out the cleaning, the device according to the invention is removed from the power plant. The four collecting receptacle modules which are screwed together can be collapsed, stacked one inside the other and so transported away and stored in a simple manner.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 014 607.2 | Mar 2008 | DE | national |
