Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Reexamination Certificate
2000-04-21
2001-12-11
Nguyen, Hoang (Department: 3748)
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
C060S605100
Reexamination Certificate
active
06327857
ABSTRACT:
Device, method and application in connection with a turbomachine and pumping and lubricating arrangement in connection with such a machine.
The present invention relates to a device in connection with a turbomachine, e.g. in the form of a model jet engine or turbo-charger, in which one or more slide bearings are disposed on one or more turbine shafts. The device utilizes lubricant, a tank system for this and an arrangement for supplying lubricant to the respective bearing. The invention also relates to a process for realizing, in a turbomachine having a turbine shaft, pump impeller and inlet unit for lubricant or lubricant-equipped propellent, joined-together assembly for a pumping and lubricating arrangement for or in the machine. The invention also relates to an integrated pumping and lubricating arrangement for a turbomachine, in which arrangement two or more bearings are disposed on one or more turbine shafts. The arrangement utilizes lubricant, a tank system for this and an arrangement for supplying lubricant to the respective bearing.
The invention also relates to the application of a fan arrangement in a jet engine which is equipped with an alternatively whole or divided engine shaft and which is primarily intended for a model aeroplane in which the fan arrangement is placed on the engine shaft in front of the compressor to the engine and in which a thrust on the aeroplane, generated by the engine, is related to the speed of the aeroplane and the frontal area of the engine. The invention also relates to a device for ensuring a small, or small as possible, frontal area dimension of a jet engine, primarily for a model aircraft in which the engine comprises an engine shaft and a compressor applied thereto and a fan arrangement disposed on the engine shaft in front of the compressor. Included under the term “model aircraft” are miniature-based aircraft of various types, i.e. including those aircraft which are used in a context other than for pure model flying, e.g. in a combat context.
PRIOR ART
Current model jet engines generally incorporate conventional deep-groove ball bearings which are lubricated with turbine oil. The oil in question is stored in a separate oil tank with the aid of compressor pressure. The fuel system can comprise a fuel tank, electric fuel pump and batteries for driving the pump. The total weight of all the components involved is approx. 500 grammes excluding the weight of the fuel.
So-called “fan engines” are previously known and are normally used on all current jet aircraft. Reference is made, inter alia, to the standard work “Gas Turbine Theory” by H. Cohen et al, “ISBN 0-582-30539-X”. It can be seen from page 100 that for aircraft requiring low air resistance (and hence a small frontal area) it is necessary to keep the so-called “by-pass ratio” low, by which is meant between 0.5 and 1. It can further be seen from the cited reference location that the use of a high by-pass ratio (exemplified as 5) results in increased air resistance due to the increasing frontal area. There is also a widespread view that a fan engine with high by-pass ratio demands a twin-spool, varied twin-spool or triple-spool construction. Compare also the reference according to the above, on page 102, FIG. 3.18.
ACCOUNT OF THE INVENTION
Technical Problem
In model aircraft and other advanced small aircraft, for example, there is a need to be able to reduce the weight of components involved. The invention aims to solve this problem, inter alia, and proposes an arrangement in which specifically oil tank, oil pump, fuel pump and batteries can be wholly eliminated or substantially reduced in weight.
There is also a need for a more reliable system with fewer components. In addition, there is a wish to be able to eliminate rotary seals which are difficult to make seal-tight. The turbine shaft or shafts must be able to rotate at high speed and there is here a need to be able to dispose the system or arrangement such that the effects of critical rotation speeds can be eliminated. There is additionally a requirement for operating reliability. If the pump packs up, for example, then the result is that the engine stops directly due to a loss of fuel pressure and the bearings are saved from damage. There is also a need to be able to eliminate the risks of so-called “coking-up”. There is additionally a need for environmentally friendly jet engines. The invention aims to solve these problems also.
Moreover, fuel consumption must be able to be kept low, as must the temperature in the body/shell of the jet engine. There is also a need to obtain increased thrust in spite of small outer dimensions. A brake arrangement must be able to be disposed rapidly and effectively on the aircraft in question. The invention solves these problems also.
With the coming into being of the present invention, the inventor has managed to combat technical prejudices in this field. There is a widespread view amongst experts in the field, for example, that a high by-pass ratio produces a low specific fuel consumption and high static thrust at the cost of a large frontal area. This view, inter alia, diverts the expert from seeking solutions according to unconventional methods, which necessitated the present invention. Despite the above prejudices, the need for a small frontal area relative to the thrust is satisfied by applying a concept which is based upon a fan engine with high by-pass ratio and the fan is mounted directly on the main shaft of the engine.
There is also a reluctance, in purely general terms, to use jet engines in the context of a model aeroplane, since they give off hot gases. The jet engine represents those types of engine which operate with an open flame behind. The invention aims to solve this problem also, inter alia, by proposing to let the fan air mix with the exhaust gases from the turbine such that the outlet temperature from the engine remains relatively low, e.g. below 300° C., which is below the ignition temperature for most commonly occurring combustible materials. By letting the fan air swill around the hot parts of the engine, a low temperature is obtained on the outer shell of the engine, making installation in model aircraft simple.
There is also a need to obtain rapid changes in the thrust of the engine. This problem also is solved by the invention. It is proposed by the invention that the fan current should be regulated. It can also be advantageous to utilize a radial turbine in the engine. Radial turbines are often the most effective turbine in small jet engines but have a greater moment of inertia than equivalent axial turbines. In purely general terms, this is considered a drawback from the regulating view-point, since rotation speed changes occur slowly in response to fuel supply. By simultaneously regulating the fuel supply and by-pass ratio, in accordance with the present invention, the thrust can be rapidly altered within wide boundaries as a result of the rotation speed being broadly constant.
There is also a wish to be able to reverse the direction of the exhaust gases in a brake context. This problem is solved by the invention by virtue of the low exhaust gas temperature. Reversing devices can thus be used to regulate quickly the thrust of the engine, e.g. upon take-off and landing.
In the case, specifically, of model aircraft, there is a wish to be able to achieve true-to-scale models. There is hence a wish, for example, that jet aeroplanes should be able to be built with associated jet engines. Problems arise in reducing the dimensions of the jet engine, with the result that the jet engine has often been determinant of the size of the model. In order to maintain trueness to scale, it has hitherto been proposed to utilize conventional combustion engines in which the problem in question has not been present. The drawback with this has been that the application of jet engines to the said models has had to be abandoned. The invention solves this problem also.
With jet engines of this type, there are also problems from a regulating viewpoint as regards the speed of the aircraf
Connolly Bove & Lodge & Hutz LLP
Nguyen Hoang
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