You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
     The present invention relates to an excavator, in particular to a mini-excavator. 
     BACKGROUND OF THE INVENTION 
     Mini-excavators are generally understood to be micro-excavators which travel on rubber crawler tracks. These machines can drive through door openings of a carcass and are used as so-called construction robots with hydraulic hammers instead of excavator shovels also when renovating buildings. 
     With such mini-excavators, the aim is undertaken to carry the greatest possible fuel supply despite the very small dimensions. Thanks to this measure, the required refuelling intervals can be kept large. In a similar way, a large supply of hydraulic oil leads to an extension of the oil-change intervals. Furthermore, a large available oil supply improves the oil cooling of the excavator hydraulics. 
     At the same time, however, an operator&#39;s cabin should be made as comfortable as possible for the operator. For example, a driver&#39;s seat should be designed with sufficient suspension, which, however, requires a lot of room in the operator&#39;s cabin. In the operator&#39;s cabin, room is additionally required for a battery, a cabin heater and, for example, for an instrument panel. As the devices named can, in total, often only be fitted with difficulty in an operator&#39;s cabin, occasionally open operator&#39;s platforms are used, for example with a roll-over bar. To provide an appropriate size to the operator&#39;s cabin, the two fluid tanks named above are normally fitted below the driver&#39;s seat or in the engine compartment. However, this has the consequence that, for example, when the fuel tank is disposed below the driver&#39;s seat, there is no room left for a cabin heater. The disposition of the hydraulic oil tank in the engine compartment, on the other hand, leads to a warming of the oil due to the engine heat so that larger oil coolers are required which, in turn, leads to increased room requirements and/or lowers the engine accessibility. 
     Another problem which occurs, in particular with mini-excavators, is that due to the strict dimension specifications, the insulation of the engine compartment or of the valve box of the excavator is only possible in an insufficient manner. For the reasons given above, sound-proofing layers of thick construction such as are usual with larger machines cannot be used with mini-excavators. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore the object of the invention to avoid the disadvantages associated with the disposition of fluid tanks in the engine compartment or in the operator&#39;s cabin and at the same time to improve the noise insulation of an excavator, in particular of a mini-excavator. 
     This object is solved by means of an excavator, in particular a mini-excavator, having the features of the present invention. By the disposing of at least one fluid tank between the engine compartment and the valve box of the excavator, it is effectively possible to dampen or insulate noise which is created in either the engine compartment or the valve box. The at least one fluid tank essentially extending over the width of the superstructure thus performs a dual function, namely the simultaneous noise dampening of the engine compartment and the valve box which are disposed separately from each other. Furthermore, in accordance with the invention, the disposition of a fluid tank within the engine compartment is avoided so that, for example in the event of a hydraulic oil tank, only an oil cooler less complex than the state of the art has to be used. Finally, thanks to the disposition in accordance with the invention of the at least one fluid tank, a larger amount of space is available in the operator&#39;s cabin. 
     In accordance with one preferred embodiment of the excavator in accordance with the invention, an operator&#39;s cabin (possessing a driver&#39;s seat) of the superstructure of the excavator is essentially formed above the at least one fluid tank. Thanks to the positioning of the operator&#39;s cabin above the fluid tank, a particularly effective noise insulation is ensured in the operator&#39;s cabin towards engine compartment noise or valve box noise. 
     Appropriately, the engine compartment, the valve box and the at least one fluid tank are disposed at least partially within a frame of the superstructure. In this way, a particularly compact and robust structure is made available. 
     Appropriately, a heating device is disposed below the driver&#39;s seat of the operator&#39;s cabin. In this way, the space made available in the operator&#39;s cabin through the disposition in accordance with the invention is utilized in an optimum manner. It is, for example, also easily possible due to the disposition of the fluid tanks in accordance with the invention to provide a driver&#39;s seat which has a relatively large construction with a spring frame in the operator&#39;s compartment. 
     In accordance with another embodiment of the present invention, for which separate protection is desired, the excavator possesses a first and a second fluid tank, with these fluid tanks abutting each other with one positive and complementary side wall each. Thanks to such a forming of abutting fluid tanks, a particularly simple installation of the tanks is possible, for example in the frame of the superstructure. The two fluid tanks can thus abut each other in a fixed manner or in a wedge-like manner while utilizing the room in an optimum manner, whereby the noise insulation effect is favorably influenced. By forming the fluid tank with side walls abutting each other obliquely, the tolerance specifications for the fluid tanks are furthermore reduced, whereby a less expensive production is possible. 
     In accordance with a preferred embodiment of the present invention, the side walls of the fluid tanks, which are inclined in each case, run parallel to the longitudinal direction of the excavator. 
     Advantageously, the at least one fluid tank is made of metal, in particular of steel, or of plastic. While steel tanks are characterized by a particularly high mechanical stability, the use in particular of plastic tanks leads to a further improvement in the noise dampening or insulation. 
    
    
     One preferred embodiment of the invention will now be described in detail by way of the enclosed drawings. 
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
     FIG. 1 shows a partially cut diagrammatic side view of a preferred embodiment of a mini-excavator in accordance with the invention; 
     FIG. 2 shows a top view of the mini-excavator from FIG. 1 with a partially removed cabin and without an engine bonnet or seat console; and 
     FIG. 3 shows a cross-section view of the fluid tank disposition along the line I—I in FIG. 2, with the installation and removal steps of the fluid tanks being indicated by interrupted lines with dots. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The mini-excavator shown in FIG. 1 possesses a caterpillar substructure  1  and a superstructure  2 . The superstructure  2  is formed with a superstructure frame  6  in which an engine compartment  10  is (partially) disposed and in which a valve box  11  is disposed. An operator&#39;s compartment  4  is disposed essentially centrally on the superstructure frame  6 . In the operator&#39;s compartment  4 , a seat console  13  is provided having a driver&#39;s seat  14  disposed thereon. Below the driver&#39;s seat  14 , a heating device  15  is disposed. 
     Two fluid tanks  20 ,  21  are disposed between t he engine compartment  10  and the valve box  11 . It can be seen from FIG. 2 that the fluid tanks  20 ,  21  together extend over the total width of the superstructure frame  6 . They thus form a partition region between the engine compartment  10  and the valve box  11 . The engine compartment  10  is limited to the rear side by an engine bonnet  17  or a tail weight  7 . 
     The engine compartment  10 , which normally possesses a high noise and heat development, is separated from the operator&#39;s cabin  4  and the valve box  11  by a console rear panel  16  of the seat console  13  of the operator&#39;s cabin  4  and the rear side walls of the tanks  20 ,  21 . The fluid tanks  20 ,  21  filled with fluid, i.e. in the present case fuel or hydraulic oil, possess a highly noise-dampening effect, in particular when they are made from plastic and are filled with fluid. For the further noise insulation of the operator&#39;s cabin, the console rear panel  16  is covered with insulation material. 
     Thanks to the disposition of the fluid tanks  20 ,  21  to absorb engine noise, any noise development in the valve box  11  can also be effectively dampened or insulated. In this way, it is possible to insulate a floor plate  18  of the operator&#39;s cabin  4  required for servicing and assembly towards the cabin with relatively little insulation material. The floor plate  18  can thus be formed essentially thinner, whereby the room available in the operator&#39;s compartment  14  is larger. 
     In the longitudinal direction of the mini-excavator, the extension of the fluid tanks  20 ,  21  towards the front is limited by the dimensions of a tilt cylinder  19  and control apparatuses  12 , in particular valves, disposed next to and above same and towards the rear by the dimensions of the engine  8  disposed in the engine compartment  10 . The tilt cylinder  19 , which effects a limited swivel of a shovel jib  3  through a tilt axis  33 , forms together with a rotating motor  35 , which moves the superstructure relative to the substructure  1  around a pivot  5 , the tank limitation to valve box  11 . 
     FIG. 2 shows, as mentioned above, that the fluid tanks  20 ,  21  extend over the full width of the superstructure  6 . Here, the fluid tank  20  abuts with a side wall  40 , and the fluid tank  21  with a side wall  41 , the inside surface of the superstructure  6 , as shown in FIG.  3 . 
     In FIG. 2, there is furthermore shown a hydraulic pump  9  connected to the fluid tank  20  designed as a hydraulic oil tank by means of suction leads  34 , which hydraulic pump  9  loads, for example, the tilt cylinder  19  with hydraulic oil by means of pressure lines  32 . Pressure lines  32  are here disposed in a line duct  31 . 
     FIG. 3 shows a cross-section through the fluid tanks  20 ,  21 , which are disposed in the superstructure frame  6 . Here, continuous lines of the fluid tanks  20 ,  21  represent the assembly position, while broken and dotted lines serve to illustrate the installation process. 
     As can be seen from the Figure, the superstructure  6  is formed on its top side with a recess by which the fluid tanks  20 ,  21  can be inserted. First, the fluid tank designed as the fuel tank  21 , which takes up around 30 to 40% of the cross-section area of the superstructure frame  6 , is inserted through the recess and pushed so far to the right until its right side wall  41  abuts the inside of the superstructure frame  6 . Subsequently, the larger second fluid tank designed as a hydraulic oil tank  20  taking up around 60% of the cross-section area can be inserted through the recess in the superstructure frame  6 . To allow an optimum use of room of the total cross-section of the superstructure frame  6 , the fuel tank  21  is formed with a positively inclined side wall  23 . The hydraulic oil tank  20  possesses a negatively inclined side wall  24  formed in a complementary manner thereto. After the introduction of the fluid tank  21  and its moving to the right up to contact with the inside of the superstructure frame  6 , the hydraulic oil tank  20  can be put into its assembly position in the manner indicated by the broken, dotted lines in FIG. 3, while utilizing the two positively or negatively inclined side walls  23 ,  24 , by means of a swivel-in movement through the recess in the superstructure frame  6 . By means of the formation of the side walls  23 ,  24  formed complementarily to each other, it is thus possible to fill up essentially the whole cross-section of the superstructure frame  6  with tank space. The line duct  31 , which takes up a small portion of the cross-section of the superstructure frame  6 , can, for the event that an intermediate space is left between the lines  32  and the hydraulic oil tank  20 , be lined against noise and heat development with insulation material. The removal of the fluid tanks  20 ,  21  is performed in the opposite order, i.e. first the hydraulic oil tank  20  is removed by means of a swivel-out movement through the recess in the superstructure frame  6  and thereafter the fuel tank  21  can also be removed in a simple manner by a movement to the left into the region of the recess. It should be noted here that the other side walls of the fluid tanks  20 ,  21  can possess a parallel, inclined or any other appropriate orientation. 
     Normally, the hydraulic oil tank  20  with its line duct  31  is located on that side of the excavator on which the hydraulic pumps  9  are also disposed. In FIG. 3, by way of example, the hydraulic oil tank  20  is shown with an inflow flange  29  with an integrated oil filter  30 . For reasons of space, it may be necessary to use a line filter so that the hydraulic oil can flow into an inflow space  28  of the hydraulic tank  20 . Normally, the hydraulic tank  20  is reinforced by a flow guide panel  27  which allows the hydraulic oil to flow in a desired direction to allow the total oil volume to participate in the mixing process. The hydraulic tank is thus divided into an inflow space  28  and a suction space  25 , on which suction line connections  26  to the hydraulic pumps  9  are affixed. Inflow space  28  and suction space  25  can be swapped in position if required. 
     The fuel tank  21  is shown in FIG. 3 by way of example with a filler connection  22  which depending on the space relationships can also be affixed to a side wall of the fuel tank  21 . 
     While this invention has been described as having preferred design, it is understood that it is capable of further modification, uses and/or adaptations following in general the principle of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as may be applied to the essential features set forth, and fall within the scope of the invention or the limits of the appended claims.

Summary:
An excavator comprises a substructure and a superstructure pivoted on the substructure with an engine compartment and a valve box of the excavator being formed in the superstructure; and at least one fluid tank disposed between the engine compartment and the valve box essentially extending over the width of the superstructure. An excavator includes a first and a second fluid tank abutting each other with one positive and complementary side wall each to provide a particularly simple installation of the tanks in a wedge-like manner while utilizing the room in an optimum manner, for example, in the frame of the superstructure.