GB2319812A - In-flight balancing of fan on turbofan jet engine - Google Patents

Abstract

An apparatus and a method for in-flight balancing of fan 10 on a turbofan jet engine, after a loss of blade 12, involves detecting an imbalance due to the loss of a blade, by means of a vibration monitor 50, optical sensors 56, a blade locator magnet (68 fig. 2), and coil (55), and a strain gauge (69 fig. 2). A computer 51 is linked via a radio link 54,62,60 to a computer 63, and a power switch 64 and voltage regulator 65 are provided. When a blade 12 is lost, the power switch 64 is caused to send electrical impulses to selected membrane valves 35, the membranes of which burn, melt or are ruptured by an explosive charge, whereby fluid communication between a tyre-shaped ring 30 and selective blade cavities 15, is effected to admit fluid to the selected cavities 15 in fan blades 12, adjacent to the place of the lost blade, to compensate for the lost mass. Fluid is supplied to the ring via a delivery line 22, centrifugal force then urging fluid into lines 34. Electrical power is supplied generated by coils (66 fig. 2) on the hub 11 rotating in relation to stationary magnets (67).

Description

APPARATUS AND METHOD FOR IN - FLIGHT BALANCING OF FAN ON TURBOFAN JET ENGINE FIELD OF THE INVENTION The present invention relates in general to the balancing of a fan on a jet engine. In particular, this invention relates to an apparatus and a method for in-flight balancing of a fan on a turbofan jet engine after the complete or partial loss of one or more of its blades.

BACKGROUND OF THE INVENTION Instances of a fan blade loss on engines of jet aircraft are well known. In some of these instances involving aircraft with large turbofan jet engines, the vibration resulting from blade loss may interfere with the pilot's ability to fly the aircraft. The problem is more serious with the recent introduction of aircraft using a new generation of large diameter fan engines that have much larger and heavier blades.

It is therefore desirable to balance the fan in-flight soon after a complete or partial loss of one or more of its blades.

SUMMARY OF THE INVENTION The present invention provides an apparatus and a method for in-flight balancing of the fan on a turbofan jet engine.

This system is capable of balancing the fan after a complete or partial loss of one or more of its blades. All blades of the fan of the turbofan jet engine incorporating this invention comprise suitable cavities, and a balancing fluid is transferred into the cavities of some of the blades during the balancing process to compensate for the mass of the missing blade or blades. The present invention, therefore, provides a system whereby the damaged fan may be rebalanced without further affecting its aerodynamic properties. Some of the new generation, large diameter turbofan jet engines use fans with hollow titanium blades, and are well suited for incorporating the fan balancing system of the present invention.

The key mechanical components of the apparatus of the present invention include: a tire shaped ring attached to and rotating with the hub of the fan, used for distribution of balancing fluid to some of the blades of the fan; remotely operated blade valves, connecting the inside peripheral section of the tire shaped ring with cavities in the fan blades; and a stationary receiver of balancing fluid with a system for metering and delivery of balancing fluid to the tire shaped ring when needed.

The key electronic components of the apparatus of the present invention include: a stationary vibration monitor and stationary and rotating computers; stationary and rotating sensors to monitor the presence of the fan blades and their tips in the fan assembly; and radio apparatus for communication between the stationary and rotating computers. The vibration monitor, and the stationary and rotating computers, must include suitable software for operation of the apparatus and method of the present invention.

The key steps in balancing the fan are: detecting the imbalance and designating the fan blades that must receive balancing fluid in their cavities to balance the fan; opening the blade valves connected to the designated blades and confirming that proper valves have been opened; calculating the quantity of balancing fluid required for balancing of the fan; and delivering the required quantity of balancing fluid into the rotating tire shaped ring from the stationary receiver.

After delivery into the tire shaped ring, balancing fluid is forced by the centrifugal force into cavities of designated blades through the open blade valves.

The apparatus of the present invention allows for transfer of balancing fluid form the stationary delivery line into the cavities in blades of the rotating fan, without the need for any type of rotary seals.

The apparatus and the method of this invention are capable of a rapid, complete or partial, balancing of the fan of a turbofan jet engine incorporating this invention after a loss of one or more of its blades, or after the fan develops in-flight imbalance for whatever reason.

OBJECTS OF THE INVENTION One object of the present invention is to provide an apparatus and a method for rapid in-flight balancing, or partial balancing, of a fan of a turbofan jet engine after such fan develops an imbalance.

Another object of the present invention is to provide an apparatus and a method for rapid in-flight balancing of a fan of a turbofan jet engine after a complete or partial loss of one of its blades.

Still another object of the present invention is to provide an apparatus and a method for rapid in-flight balancing, or partial balancing, of fan of a turbofan jet engine after a complete or partial loss of two or more of its blades.

Yet another object of the present invention is to provide an apparatus and a method for rapid in-flight balancing of the fan of a turbofan jet engine that is simple, inexpensive and dependable in operation, and adaptable to existing turbofan jet engines with only minor modifications.

Another object of the present invention is to provide an apparatus and a method that may allow, under certain circumstances, for emergency use of the engine with a rebalanced fan in the event that the other engine or engines on the affected aircraft fails or fail to operate.

These and other objects of the present invention will become apparent when reading the enclosed detailed description in view of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of the apparatus that may be used, in accordance with the present invention, for in-flight balancing of the fan of a turbofan jet engine after the loss of one or more of its blades.

Figure 2 is a more detailed drawing of the hub section of the fan, incorporating some of the details of the present invention.

Figure 3 is a cross section view of the tire shaped ring used to distribute the balancing fluid to blade valves leading to the cavities in the fan blades.

Figure 4 is a cross section view of the membrane type blade valve in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT References will now be made in detail to the preferred embodiments of the present invention. While the present invention will be described in conjunction with the preferred embodiments, it shall be understood that such description is not intended to limit the scope of the present invention to the preferred embodiments described below. To the contrary, the present invention is intended to cover other alternatives, modifications, additions, and improvements, all of which may be included within the scope of the present invention, as defined by the claims attached thereto.

Referring now to Figure 1, the fan assembly of a turbofan jet engine incorporating this invention is indicated by numeral 10. Fan 10 comprises hub 11 to which blades 12 are attached.

Hub 11 is covered by cover 13, and fan 10 is enclosed within nacelle 14. Fan 10 rotates around axis X-X. All blades 12 of fan 10 may be assigned consecutive numbers from 1 through n (n equals the number of blades 12 in fan 10) in any direction, begining with any blade assigned number 1. For the purpose of this application and accompanying claims, terms "lost blade" or "losing a blade" shall mean the complete or partial loss of blade 12 from fan 10, unless specifically indicated otherwise.

Each blade 12 of fan 10 has suitable cavity 15, ending with a passageway 16 at the end of blade 12 adjacent to hub 11. Passageways 16 extend from the outside of blades 12 into cavities 15 to provide openings for transfer of balancing fluid into cavities 15 during balancing of fan 10.

For the best operation of the balancing system of this invention, cavities 15 in blades 12 should extend as far away from hub 11 inside blades 12 as possible to provide for positioning of balancing fluid, forced by the rotation of fan 10, as far as possible from the center of rotation around axis X-X. Also, the volume of cavities 15 in blades 12 should be as large as possible to accomodate the maximum possible quantity of balancing fluid, and a suitable vent hole should be provided for each cavity 15 at a position close to hub 11 (vent holes are not shown in Figures 1 or 2).

The choice of balancing fluid is very important.

Balancing fluid must remain liquid and have sufficiently low viscosity at very low temperatures, and its specific weight should be as high as possible. In certain circumstances, jet fuel may be used for complete or partial balancing of fan 10 after a loss of one of its blades, or after partial loss of two adjacent blades.

Numerals 20 through 25 of Figure 1 indicate key stationary mechanical components of the apparatus of this invention.

Numeral 20 in Figure 1 indicates a suitable receiver of balancing fluid. Receiver 20 is connected on its outlet side to a suitable valve 21, which is further connected to delivery line 22 used for delivery of balancing fluid from receiver 20 to the rotating mechanical components of the apparatus of this invention, located close to hub 11. Receiver 20 is also connected to valve 23, which is further connected to suitable line 24 that delivers compressed air to pressurize receiver 20 when necessary. Valves 21 and 23 may be any suitable valves such as electrically operated solenoid valves.

Also, any suitable pump may be used for the transfer of balancing fluid from receiver 20 to delivery line 22. Receiver 20 may have a suitable vent valve 25 to depressurize receiver 20 when required. The flow of balancing fluid from receiver 20 into delivery line 22 may also be regulated by pressurizing and depressurizing receiver 20 by alternate use of pressure supply valve 23 and depressurization or vent valve 25.

Key stationary mechanical components of this invention may be located in any suitable place, such as inside nacelle 14.

Numerals 30 and 35 of Figure 1 indicate key rotating mechanical components of the apparatus of this invention.

Numeral 30 indicates a tire shaped ring, located on the side of and rotating with hub 11 of fan 10, and numeral 35 indicates blade valves, located between tire shaped ring 30 and cavities 15 of blades 12. The peripheral inside section 33 of tire shaped ring 30 is connected through lines 34 to blade valves 35, and further through lines 36 and passageways 16 with cavities 15 in blades 12. In this manner, tire shaped ring 30 is connected to cavity 15 of each blade 12 of fan 10 through a separate blade valve 35.

The key rotating mechanical components of the apparatus of this invention are better shown in view of Figure 2 of the drawings, which is an enlarged sectional view of the central hub section of fan 10.

Figure 3 is a cross sectional view showing more details of tire shaped ring 30. Tire shaped ring 30 is substantially a "tire shaped", narrow body consisting of two axially spaced disks 31, each having a circular opening in the center, like side walls of a tire, and outside peripheral edges connected by outside peripheral wall 32, creating inside peripheral section 33. The circular openings in centers of axially spaced disks 31 are for clearing the main shaft of the jet engine incorporating the present invention. A gap between axially spaced disks 31, close to the axis X-X, provides an opening for the end of delivery line 22, which originates from receiver 20.

During balancing of fan 10, the role of tire shaped ring 30 is to receive balancing fluid from delivery line 22 and force it by centrifugal force into its inside peripheral section 33 and through lines 34, opened blade valves 35, lines 36, and passageways 16 into cavities 15 of blades 12 designated to receive balancing fluid for balancing of fan 10. This arrangement allows for transfer of balancing fluid from receiver 20 into rotating fan 10, without the need for any type of rotary seals. To prevent or minimize spillage of the balancing fluid, tire shaped ring 30 should have the maximum possible outside diameter and minimum possible diameter of circular openings in its axially spaced disks 31, should be as narrow as possible, and the outlet portion of delivery line 22 should be pointed downward between axially spaced disks 31.

Blade valve 35 is an important component of the apparatus of this invention. Blade valves 35 should be positioned as close to tire shaped ring 30 as possible, and may be connected directly to, or made a part of, tire shaped ring 30 to avoid loss of any blade valve 35 if its blade 12 of fan 10 departs.

Connecting lines 36 between each blade valve 35 and passageway 16 in blade 12 should allow for blade 12 departure without damaging its blade valve 35. Blade valves 35 may be, for instance, electrically operated solenoid valves, or any suitable valves that may be remotely operated and tested to determine whether they are opened or closed.

Figure 4 of the drawings shows details of one alternate embodiment of blade valve 35. The advantages of this type of blade valve 35 are its compactness and light weight. This type of blade valve 35 is essentially a tubular housing 40 made of material that does not conduct electricity, such as a suitable ceramic material, separated into two sections 41 and 42 by a suitable metal membrane 43 having suitable lead wires 44 connected to it at opposite sides. To provide for tight sealing between sections 41 and 42 of blade valve 35, membrane 43 may be seated and sealed against seat 45 in tube 40 by use of any suitable adhesive. For proper operation of blade valves 35, the material and thickness of membranes 43 should be such as to allow for burning or melting of membranes 43 by a suitable surge of electric current before use of blade valve 35, if such valve 35 connects to a blade 12 designated to receive balancing fluid. On the other hand, membranes 43 in blade valves 35 should be of sufficient thickness and strength to provide a barrier capable of preventing any flow or leakage of balancing fluid from tire shaped ring 30 through blade valves 35 that lead to cavities 15 of blades 12 that are not designated to receive balancing fluid when such balancing fluid is present in tire shaped ring 30. The pressure imparted on membranes 43 by balancing fluid rotating with tire shaped ring 30 may be utilized to provide tight sealing of membranes 43 against their seats 45 by installing blade valves 35 with section 41 connected toward tire shaped ring 30, and section 42 facing toward blades 12. To provide redundancy, two or more membranes 43 may be spaced alongside tube 40, creating a multiple blade valve 35 with multiple pairs of lead wires 44.

Membranes 43 may be provided with a deposit of suitable chemical capable of burning at a temperature high enough to burn through or melt membranes 43, or a suitable explosive for bursting membranes 43 (collectively the "charge"), indicated by numeral 47, and suitable ignition wires, performing the function of lead wires 44, may be run directly through charge 47.

Referring again to Figures 1 and 2, numerals 50 through 56 indicate the main stationary electronic components of the apparatus of the present invention, while numerals 60 through 66, 68 and 69 indicate other electronic components of the apparatus of this invention that rotate with fan 10. The role of the electronic components is to constantly monitor operation of fan 10, to detect and analyze imbalance of fan 10 when it occurs, to designate which blades 12 are to receive balancing fluid, and to control the balancing process when necessary.

Numeral 50 in Figure 1 indicates a vibration monitor used to monitor the vibration caused by rotation of fan 10 at all times during its operation. Vibration monitor 50 is an electronic computer connected to a suitable sensor or sensors located in suitable positions inside the engine. When fan 10 loses blade 12, monitor 50 calculates the amount of the imbalance and its angular position in fan 10, including identification of the lost blade 12, and communicates that information to stationary computer 51.

Numeral 51 in Figure 1 indicates a stationary computer that controls and coordinates all facets of the operation of the balancing system of this invention. This activity requires communication between both stationary and rotating electronic components of the apparatus of this invention. Because fan 10 is a fast rotating assembly, the preferred way to provide instant and reliable communication between stationary and rotating electronic components of the apparatus of the present invention is via radio means. To communicate with rotating electronic components, stationary computer 51 sends required commands via line 52 to a radio transmitter-receiver 53 located, for instance, in nacelle 14 in front of fan 10 and blades 12. The signal is then beamed from transmitter 53 via antenna 54 in the direction of antennas of an appropriate receiver that rotates with fan 10.

The main role of stationary computer 51 is to confirm findings of vibration monitor 50, to designate blades 12 that must receive balancing fluid in their cavities 15 for balancing of fan 10, and to control the balancing process.

Vibration monitor 50 and/or stationary computer 51 must determine the exact angular position of the imbalance in fan 10 in relation to position of at least one of blades 12, before stationary computer 51 may designate blades 12 for receipt of balancing fluid in their cavities 15 for balancing of fan 10.

It may be, therefore, advantageous for stationary computer 51 to have the means to determine the position of any blade 12 in relation to stationary parts of the engine at any given moment of time. This may be done by use of a so called "magnetic angle marker" or blade locator on at least one blade, for instance on blade number 1. Blade locator may comprise blade locator magnet 68 located in a suitable position on fan 10, for instance in or on hub 11 between blade number 1 and axis X-X of fan 10, and suitable stationary coil 55 positioned so that blade locator magnet 68, rotating with hub 11, passes close to and over such coil 55 once per each revolution of fan 10. Lead wires of coil 55 are connected to vibration monitor 50 and stationary computer 51 (such connections are not shown in Figures 1 and 2). Every time blade locator magnet 68 passes close to and over coil 55, it generates a sharp electrical impulse in coil 55, which marks the presence of blade number 1 in that particular position at that instant of time. With the position of blade number 1 identified from such signal, vibration monitor 50 and/or stationary computer 51 can determine the exact position of any blade of fan 10 at that instant of time. The location of blade locator magnet 68 in or on hub 11 of fan 10 guarantees that signals from coil 55 marking the position of blade number 1 will continue, even if blade number 1 is lost from fan 10.

In addition to vibration monitor 50, the apparatus of the present invention may also have other stationary blade monitoring means for monitoring the presence of blades 12 in the rotating fan 10. One such stationary blade monitoring means may be an optical sensor 56, used to monitor the presence of tips 17 of blades 12 rotating with fan 10. Optical sensor 56 may be any suitable device, based on either ordinary light, laser or radio technology. Optical sensor 56 includes a light emitting device, such as a light emitting diode, and a sensor receiving the reflected light. Optical sensor 56 operates by sending light or laser beam toward tips 17 of rotating blades 12 and then receiving and analyzing the beam reflected from the blade tip surfaces. If shielding from daylight is required, then the best position for location of optical sensor 56 appears to be on the top inside of nacelle 14, in front of fan 10, but optical sensor 56 may be additionally shielded by a suitable shield with only small openings allowing for passage of emitted and reflected light beams only. For best performance of optical sensor 56, the surfaces of tips 17 exposed to light or laser beams from optical sensor 56 may require special surface treatment or preparation. Confirmed presence of tip 17 of blade 12 by optical sensor 56 indicates that such blade is present in the rotating fan 10, that its mechanical integrity has not been, most likely, compromised, and that such blade may be designated to receive balancing fluid if necessary. Optical sensor 56 shall be connected to stationary computer 51.

Vibration monitors 50, computers 51, radio communication equipment, optical sensors 56, and magnetic angle markers as described above are well known in the art, and their design and operation will not be described here in more detail. The functions of vibration monitor 50 and stationary computer 51 could be integrated into one device.

The electronic components that rotate with hub 11 of fan 10, preferably inside hub cover 13, include a radio receiver-transmitter 60 connected via lines 61 to antenna or antennas 62, rotating computer 63 connected to power switch 64, and wiring connecting power switch 64 with appropriate lead wires 44 (not shown) or ignition wires of blade valves 35.

Receiver-transmitter 60 sends signals received from stationary computer 51 to rotating computer 63, and sends return signals received from rotating computer 63 to its antenna or antennas 62 for transmittal to antenna or antennas 54 of stationary electronics, for further transmittal to stationary computer 51. Stationary antenna or antennas 54 and rotating antenna or antennas 62 should be incorporated into nacelle 14 and cover 13 of hub 11, respectively, in such a way so they do not interfere with aerodynamic performance of these components.

Rotating computer 63, after receiving commands from stationary computer 51 via radio means through transmitters-receivers 53 and 60, activates power switch 64 to direct suitable electrical impulses to designated blade valves 35 to open them, or to test whether they are closed or open, as necessary.

If blade valves 35 are membrane type valves, power switch 64 directs suitable electrical impulses to lead or ignition wires 44 of membranes 43 of blade valves 35 connected to blades 12 designated to receive balancing fluid in their cavities 15.

These electrical impulses should be strong enough to melt or burn each membrane 43 like a fuse, or to ignite the burning or explosive charges on membranes 43. After all membranes 43 in blade valves 35 of designated blades 12 have been melted or burned, rotating computer 63 causes power switch 64 to direct weak electrical impulses to membranes 43 of blade valves 35 of designated blades 12 to check, by measuring their resistance, whether they have been melted or burned and whether the valve is open or not. If blade valves 35 have multiple membranes 43, the above sequence of melting membrane 43 and checking whether it has opened must be repeated seperately for each membrane 43 in each of the designated blade valves 35.

The rotating electronic components of the apparatus of the present invention may also include rotating blade monitoring means for monitoring the presence of blades 12 in the rotating fan 10. One such rotating blade monitoring means may be suitable strain gauges 69 placed in suitable positions on blades 12, close to hub 11, as indicated in Figure 2. The strength of the strain gauge signal depends on the mass of blade 12, its geometry, and the rotational speed of fan 10.

Therefore, the comparison of the actual strain gauge 69 signal from any blade 12 with the anticipated strain gauge signal for the then actual rpm of fan 10, provides information about the presence or lack of such blade 12, or a part of it, in fan 10.

Signals from strain gauges 69 can be routed via radio means described herein to stationary computer 51, and analysis of such signals could indicate the presence or lack of presence, partial or complete, of any blade 12.

Fan 10 may be equipped with other suitable blade monitoring means to detect when any of its blades is lost or have a part of it missing. Signals from such other blade monitoring means can be routed via radio means described herein to stationary computer 51, and analysis of such signals could indicate the presence or lack of presence, partial or complete, of any blade 12 in fan 10.

Information from optical sensor 56, strain gauges 69, or from any other suitable blade monitoring means, may be used by stationary computer 51 as information supplemental to information regarding the imbalance of fan 10, developed by vibration monitor 50, or it may be used as primary information for designating blades 12 for receipt of balancing fluid for balancing of fan 10 when necessary.

The design and operation of electronic components of this invention that rotate with fan 10, including receiver-transmiter 60, its antennas 62, rotating computer 63, and power switch 64, are well known in the art and their design and operation will not be described here in more details. The role of stationary computer 51 may be performed by rotating computer 63. The rotating electronic components should be designed for reliable operation in a specific jet engine environment. In particular, rotating electronic components of the apparatus of this invention should be positioned in or close to the axis of rotation X-X to minimize influence of the centrifugal forces involved, and should be capable of withstanding any such forces that may be present during the operation.

Any suitable source of power may be used to power rotating electronic components of the apparatus of this invention. One means, shown in Figure 2, provides wire coils 66 on the engine side of hub 11 of fan 10 that rotate close to suitable stationary magnets 67, to provide for alternator-like rotating source of electricity. Lead wires from coils 66 may be run to a suitable voltage regulator 65. Voltage regulator 65 conditions power from wire coils 66 and supplies electricity as required to power radio receiver-transmitter 60, rotating computer 63, and power switch 64. Voltage regulator 65 should be capable of providing strong, bursting electrical impulses capable of melting or burning of membranes 43, or igniting their explosive-like coating, and weak electrical impulses, suitable for testing of valves 35 only, and not for burning of membranes 43 or for igniting their charges. Another source of electrical power to rotating electronic components could be a suitable battery, positioned for instance on or close to the axis X-X of rotation of fan 10 and within cover 13 of hub 11.

Such battery would have to be replaced periodically. Blade locator magnet 68 may be positioned in hub 11 next to blade number 1 and between wire coils 66, and blade locator coil 55 may be positioned between stationary magnets 67 at the same distance from axis X-X, or they may be positioned closer to axis X-X if necessary.

A suitable emulsion or slurry like mixture made of a suitable liquid mixed with small heavy particles, for instance stainless steel particles or small balls, may be used as balancing fluid. In such mixture, liquid is used mostly as a carrier to help in moving heavy particles or balls toward their destination. If such mixture of liquid and metal particles is used to fill cavities 15 during balancing of fan 10, the centrifugal force resulting from rotation of fan 10 will force metal particles toward the ends of blades 12 away from hub 11.

Following that, excess liquid can flow out from cavities 15 through vent holes, resulting in mostly metal particles filing cavities 15 and performing the balancing function.

If an emulsion or slurry like mixture is used as a balancing fluid, a suitable quantity of clean liquid, free of any metal particles, may be first transferred into cavities 15 of the designated blades 12 to provide a damping effect for metal particles entering cavities 15 later under the centrifugal force. Use of the emulsion or slurry like mixture of a liquid with stainless steel particles, or other heavy particles, may allow for balancing of fan 10 with two missing adjacent blades, and partial balancing with three or four missing adjacent blades.

Because the balancing apparatus and method of this invention are intended for use only in emergency situations, the mixture of liquid and powdered metal in receiver 20 may form clumps or solidify if stored for an extended period of time, and suitable means will have to be provided to avoid it.

One solution may be to provide receiver 20 with a suitable vibration inducing device or an ultrasound generator to provide constant stirring of the mixture. Also, separate receivers may be used for storage of liquid and powdered metal, and both components may be mixed only when needed.

To prevent clumping and uneven accumulation of metal particles on the inside periphery of tire shaped ring 30 if an emulsion or slurry like balancing fluid is used to balance fan 10, the end of delivery line 22 inside tire shaped ring 30 may rest on, or may be formed into, the shape of a suitable stationary shovel 27, to act as a shovel and spread metal particles evenly on the inside periphery of rotating tire shaped ring 30.

Vibration monitor 50, stationary computer 51, and rotating computer 63, should be provided with software allowing the apparatus of the present invention to operate as described below in section: "The Operation of the Preferred Embodiment", and to perform steps as described below in section "Method for In-flight Balancing of Fan on Turbofan Jet Engine".

All stationary electronic components of the apparatus of the present invention are operationally connected together as required for their operation, and all rotating electronic componets of the prese

THE OPERATION OF THE PREFERRED EMBODIMENT The operation of the preferred embodiment of the present invention will now be presented in a summary form.

During the operation of the apparatus of this invention, vibration monitor 50 continuously monitors the vibration of fan 10, and stationary computer 51 monitors the presence of blades 12 and their tips 17 in fan 10, utilizing signals from strain gauges 69 and optical sensor 56. When fan 10 loses a blade 12, vibration monitor 50 detects the loss, calculates the amount of the imbalance and its angular location in fan 10, including identification of lost blade 12, and communicates that information to stationary computer 51.

Stationary computer 51 receives and analyzes the input signals from vibration monitor 50, strain gauges 69, and optical sensor 56. After receiving the information about the inbalance of fan 10 from vibration monitor 50, stationary computer 51 designates blades 12 that must receive balancing fluid in their cavities 15 to balance fan 10, and calculates how much fluid is required. Next, using signals from strain gauges 69 and optical sensor 56, stationary computer 51 confirms that blades 12 designated to receive balancing fluid are present in fan 10 and have their tips 17 intact, confirming that such blades are in condition to receive balancing fluid.

Next, to avoid transfer of balancing fluid to the wrong blades, stationary computer 51 confirms that designated blades 12 are located on both sides of and adjacent to the place of the lost blade or blades 12 if only one single blade 12 or two adjacent blades 12 are missing, or that such designated blades 12 are located first between the places of the lost blades 12 if non adjacent blades 12 are missing, and then on the outside of the places of missing blades 12. After stationary computer 51 makes the final designation of blades 12 that must receive balancing fluid, stationary computer 51 sends a set of appropriate commands via line 52 to radio transmitter-receiver 53, and these commands are then transmitted from transmitter 53 via antenna 54 in the direction of antenna or antennas 62 located inside or on sides of cover 13 of hub 11.

From antenna or antennas 62, the signal from stationary computer 51 is transferred via line 61 to rotating radio receiver-transmitter 60, and then to rotating computer 63.

Rotating computer 63 then activates power switch 64 to direct suitably strong electrical impulses to membrane blade valves 35 leading to cavities 15 in the blades 12 that are designated to receive balancing fluid, to open such blade valves 35 in an appropriate way.

When all blade valves 35 leading to cavities 15 in blades 12 that are designated to receive balancing fluid have been opened, stationary computer 51 and rotating computer 63 again communicate and check all blade valves 35 by activating power switch 64 to direct suitably weak, probing electrical impulses to these valves, to confirm that only blade valves 35 leading to cavities 15 in blades 12 that are designated to receive balancing fluid have been open, and that all blade valves 35 leading to cavities 15 in blades 12 that are not designated to receive balancing fluid are closed.

After stationary computer 51 determines that all blade valves 35 leading to cavities 15 in blades 12 that are designated to receive balancing fluid have been opened and that all other blade valves 35 are closed, stationary computer 51 directs valve 23 on balancing fluid receiver 20 to open to pressurize receiver 20. After receiver 20 has been pressurized, stationary computer 51 directs valve 21 to open for an appropriate length of time to allow for an initial quantity of balancing fluid, equal to a fraction of the quantity needed for balancing of fan 10, to flow from receiver 20 through delivery line 22 into tire shaped ring 30. From tire shaped ring 30, the balancing fluid is forced by the centrifugal force through lines 34, open valves 35, lines 36, and passageways 16 into cavities 15 of designated blades 12.

After the first transfer of the initial quantity of balancing fluid has been deposited in cavities 15 of blades 12 that are designated to receive it, vibration monitor 50 and stationary computer 51 determine the improvement in balancing of fan 10. Next, stationary computer 51 calculates an additional quantity of balancing fluid to be transferred to cavities 15 of designated blades 12 to further balance fan 10, and issues an appropriate command to valve 21 to open for an appropriate length of time as required for transfer of the additional quantity of balancing fluid. Each new transfer of balancing fluid from receiver 20 into cavities 15 of designated blades 12 should be followed by vibration monitor 50 and stationary computer 51 checks of improvement in balancing of fan 10 to confirm that proper balancing is taking place.

The last two steps of operation of the balancing apparatus of the present invention, involving transfer of the additional quantity of balancing fluid to cavities 15 of designated blades 12 and check of the level of improvement in balance of fan 10, are repeated until balancing of fan 10 is completed. During these steps, the quantity of balancing fluid for transfer to blades 12 may be adjusted by stationary computer 51 as necessary.

If suitable solenoid type valves are used as blade valves 35, these valves could be operated individually as needed, one or more at a time, before or after the deposit of balancing fluid inside tire shaped ring 30.

The operation of the apparatus of the preferred embodiment of the present invention is presented in a more detailed form in the next section "Method for In-flight Balancing of Fan on Turbofan Jet Engine In addition, the operation of the aparatus of the preferred embodiment of the present invention may include: 1. using rotating computer 63 to perform functions of the stationary computer 51; 2. rapidly responding to an imbalance and begining balancing of fan 10 when the rotational speed of fan 10 is changing, as may be the case immediately following a loss of blade 12; 3. confirming that the designated blades 12 are located on both sides of and adjacent to the place of the lost blade 12 if only one single blade 12 or two adjacent blades 12 are missing, or that such designated blades 12 are located first between the places of lost blades 12 if non adjacent blades 12 are missing, and then on the outside of the places of missing blades 12; 4. distributing the required quantity of balancing fluid to as many blades 12 of fan 10 as possible, preferably in equal quantities to each blade, to minimize the centrifugal forces resulting from the presence of balancing fluid inside blades 12; 5. using pressurizing valve 23 and depressurizing or vent valve 25 to provide for transfer of balancing fluid from receiver 20 into delivery line 22 for delivery to tire shaped ring 30, if use of valve 21 for metering the flow of balancing fluid from receiver 20 into delivery line 22 proves not feasible; 6. including "prepackaged" balancing sequences for a variety of imbalance combinations that may depend on the number of blades 12 lost and their positions in fan 10; and 7. having certain or all of its components, functions or procedures redundant as required.

METHOD FOR IN-FLIGHT BALANCING OF FAN ON TURBOFAN JET ENGINE A method for in-flight balancing of a fan on a turbofan jet engine incorporating the apparatus of the present invention, as more explicitly set forth previously, includes, in substantially the following order, the following steps of: 1. continuous monitoring by vibration monitor 50 of vibration of fan 10, and by stationary computer 51, by analyzing information from strain gauges 69 and optical sensor 56, of presence of blades 12 and their tips 17 in fan 10; 2. continuous monitoring by vibration monitor 50 and/or stationary computer 51 of the position of blade number 1 of fan 10 by analyzing signals from blade locator coil 55; 3. detecting by vibration monitor 50 and stationary computer 51 of a loss of blade 12 from fan 10, and the resulting imbalance of fan 10, by analyzing information from their sensors; 4. calculating by stationary computer 51 of the amount and location of the imbalance in fan 10, including identification of the lost blade 12, by analyzing information from vibration monitor 50, and from blade locator coil 55 if necessary; 5. confirming by stationary computer 51 of the above calculations by analyzing information from strain gauges 69, and optical sensor 56; 6. designating by stationary computer 51 of blades 12 of fan 10 that must receive balancing fluid into their cavities 15 to balance fan 10, and calculating the quantity of balancing fluid required; 7. confirming by stationary computer 51, by analyzing signals from strain gauges 69, that blades 12 designated to receive balancing fluid are present in fan 10; 8. confirming by stationary computer 51, by analyzing signals from optical sensor 56, that tips 17 of blades 12 designated to receive balancing fluid are intact, confirming that such blades 12 are complete in fan 10 and are, therefore, in condition to receive balancing fluid; 9. having stationary computer 51 send a signal via radio means to rotating computer 63, directing it to activate power switch 64 to send suitably strong electrical impulses to all blade valves 35 leading into cavities 15 of blades 12 that are designated to receive balancing fluid to open these valves; 10. having stationary computer 51 send a signal via radio means to rotating computer 63, directing it to activate power switch 64 to send suitably weak, probing electrical impulses to the same blade valves 35 leading to cavities 15 of blades 12 that are designated to receive balancing fluid to check and confirm that such blade valves 35 have been opened; 11. having stationary computer 51 send a signal via radio means to rotating computer 63, directing it to activate power switch 64 to send suitably weak, probing electrical impulses to all blade valves 35 leading to cavities 15 of blades 12 that are not designated to receive balancing fluid to check and confirm that such blade valves 35 are closed; 12. directing valve 23 on balancing fluid receiver 20 to open to pressurize balancing fluid receiver 20; 13. directing valve 21 to open for an appropriate length of time to allow for metering of an initial quantity of balancing fluid, equal to a fraction of the quantity of the balancing fluid required for balancing of fan 10, to flow from receiver 20, through delivery line 22 and its outlet end, into tire shaped ring 30; 14. forcing balancing fluid with the centrifugal force from the inside peripheral section 33 of tire shaped ring 30, through lines 34, open blade valves 35, lines 36 and passageways 16 into cavities 15 of blades 12 that are designated to receive balancing fluid, while preventing the flow of balancing fluid from tire shaped ring 30 into cavities 15 of blades 12 that are not designated to receive balancing fluid by closed blade valves 35; 15. calculating by stationary computer 51 of the improvement in balancing of fan 10 after the transfer of the initial quantity of balancing fluid into cavities 15 of blades 12 that are designated to receive it by analyzing new information from vibration monitor 50 to determine that proper balancing of fan 10 is taking place; 16. calculating by stationary computer 51 of an additional quantity of balancing fluid required for the next step of balancing of fan 10; 17. directing valve 21 to open for an appropriate length of time to allow for the additional quantity of balancing fluid to flow from receiver 20, through delivery line 22, into tire shaped ring 30; 18. forcing balancing fluid with the centrifugal force from the inside peripheral section 33 of tire shaped ring 30, through lines 34, open blade valves 35, lines 36 and passageways 16 into cavities 15 of blades 12 that are designated to receive balancing fluid, while preventing the flow of balancing fluid from tire shaped ring 30 into cavities 15 of blades 12 that are not designated to receive balancing fluid by closed blade valves 35; 19. calculating by stationary computer 51 of the improvement in balancing of fan 10 after the transfer of the additional quantity of balancing fluid into cavities 15 of blades 12 that are designated to receive it, by analyzing new information from vibration monitor 50 to determine that proper balancing of fan 10 is taking place; 20. repeating the last four steps until the required balancing of fan 10 is achieved, then terminating balancing of fan 10; 21. closing valve 23 leading from the pressure source to balancing fluid receiver 20; 22. depressurizing balancing fluid receiver 20 by activating depressurizing or vent valve 25; and 23. using vibration monitor 50 and stationary computer 51 to continue monitoring the vibration of fan 10 and presence of blades 12 in fan 10 by analyzing information from vibration monitor 50, strain gauges 69, and optical sensor 56.

If the apparatus of the present invention includes electrically operated solenoid type valves as blade valves 35, then this method may include the steps of operation of these valves on "as needed" basis, one or more at a time, before or after the deposit of balancing fluid inside tire shaped ring 30.

If the apparatus of the present invention includes blade valves 35 with membranes 43, then this method for in-flight balancing of a fan on a turbofan jet engine should include, in substantially the following order, the additional steps of: 1. sending a signal from stationary computer 51 via radio means to rotating computer 63, directing it to activate power switch 64 to send suitably strong electrical impulses to lead or ignition wires 44 of membranes 43 in blade valves 35 leading to cavities 15 of blades 12 that are designated to receive balancing fluid, to melt or burn those membranes 43, or to ignite the burning or explosive charges attached to them; 2. sending a signal from stationary computer 51 via radio means to rotating computer 63, directing it to activate power switch 64 to send suitably weak, probing electrical impulses to lead or ignition wires 44 of the same membranes 43 in blade valves 35 leading to cavities 15 of blades 12 that are designated to receive balancing fluid, to check whether such membranes 43 have been melted or burned and whether they are open for the flow of balancing fluid; 3. repeating the last two steps until all membranes 43 in all blade valves 35 leading to cavities 15 of blades 12 that are designated to receive balancing fluid have been opened and confirmed that they are open; and 4. sending a signal from stationary computer 51 via radio means to rotating computer 63, directing it to cause power switch 64 to send suitably weak, probing electrical impulses to lead or ignition wires 44 of membranes 43 in blade valves 35 leading to cavities 15 of blades 12 that are not designated to receive balancing fluid, to confirm that such membranes 43 have not been melted or burned and that these blade valves 35 are closed.

The above described method for in-flight balancing of a fan on a turbofan jet engine of the present invention, as more explicitly set forth previously, may include the following additional steps of: 1. using rotating computer 63 to perform functions of the stationary computer 51; 2. rapidly responding to an imbalance and begining balancing of fan 10 when the rotational speed of fan 10 is changing, as may be the case immediately following a loss of blade 12; 3. confirming that the designated blades 12 are located on both sides of and adjacent to the place of the lost blade 12 if only one single blade 12 or two adjacent blades 12 are missing, or that such designated blades 12 are located first between the places of lost blades 12 if non adjacent blades 12 are missing, and then on the outside of the places of missing blades 12; 4. distributing the required quantity of balancing fluid to as many blades 12 of fan 10 as possible, preferably in equal quantities to each blade, to minimize the centrifugal forces resulting from the presence of balancing fluid inside blades 12; 5. using pressurizing valve 23 and depressurizing or vent valve 25 to provide for transfer of balancing fluid from receiver 20 into delivery line 22 for delivery to tire shaped ring 30, if use of valve 21 for metering the flow of balancing fluid from receiver 20 into delivery line 22 proves not feasible; 6. including "prepackaged" balancing sequences for a variety of imbalance combinations that may depend on the number of blades 12 lost and their positions in fan 10; and 7. having certain or all of its steps, functions or procedures redundant as required.

While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for the purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments, alternatives, modifications, additions, and improvements, and that certain of the details described herein can be varied considerably without departing from the basic principles of this invention.

Claims (42)

CLAIMS What I claim as my invention is:

1. In a turbofan jet engine having a fan with a hub and a plurality of blades attached to said hub, and wherein each of said blades has a suitable cavity, the improvement comprising an apparatus for balancing of said fan after said fan develops an imbalance after losing a blade, said apparatus comprising: a supply of a suitable balancing fluid; balancing means for balancing of said fan, said balancing means comprising: control means for monitoring the operation of said fan and for detecting and analyzing said imbalance; for designating certain of said blades to receive said balancing fluid in said cavities to balance said fan; and for controling said balancing of said fan; and transfer means for transfer of said balancing fluid into said cavities of said designated blades of said fan; whereby said balancing fluid transferred into said cavities of said designated blades substitutes for the mass of said lost blade to balance said fan.

2. The apparatus of Claim 1 wherein said control means comprise stationary control means that comprise a suitable stationary computer, and wherein said control means further comprise rotating control means that rotate with said fan and comprise a suitable rotating computer.

3. The apparatus of Claim 2 wherein said stationary computer and said rotating computer communicate via radio means, wherein said radio means comprise a stationary radio apparatus and a rotating radio apparatus that rotate with said fan, wherein said stationary radio apparatus comprises a radio transmitter-receiver connected to said stationary computer and at least one stationary antenna, and wherein said rotating radio apparatus comprises a radio transmitter-receiver connected to said rotating computer and at least one rotating antenna, said stationary antenna and said rotating antenna positioned as needed for communication between said stationary radio apparatus and said rotating radio apparatus.

4. The apparatus of Claim 3 wherein said stationary control means further comprise a vibration monitor for monitoring vibration of said fan during its operation, and for detecting and analyzing said imbalance.

5. The apparatus of Claim 3 wherein said rotating control means further comprise suitable strain gauges, positioned on said blades adjacent to said hub of said fan, for monitoring the presence of said blades in said fan during its operation.

6. The apparatus of Claim 3 wherein said blades have tips remote from said hub of said fan, and wherein said stationary control means further comprise a suitable optical sensor, positioned in front of said tips, for monitoring the presence of said tips of said blades in said fan during its operation.

7. The apparatus of Claim 3 wherein said transfer means comprise: distributing means for distributing said balancing fluid to said designated blades of said fan; and delivery means for delivery of said balancing fluid to said distributing means.

8. The apparatus of Claim 7 wherein said distributing means comprise: a tire shaped ring comprising two axially spaced disks, each of said axially spaced disks having a circular opening in the center and an outside peripheral edge, said axially spaced disks sealingly connected on said outside peripheral edges in forming said tire shaped ring and a peripheral section of said tire shaped ring, said tire shaped ring attached to and rotating with said hub of said fan; a passageway in each of said blades of said fan, said passageways connecting said cavities of said blades with outside of said blades at the ends of said blades adjacent to said hub of said fan; and at least one remotely operated blade valve for each of said blades of said fan, said blade valves located between said peripheral section of said tire shaped ring and said passageways leading into said cavities of said blades, said blade valves providing passages between the inside of said peripheral section of said tire shaped ring and said cavities of said blades when opened.

9. The apparatus of Claim 8 wherein said remotely operated blade valves are electrically operated membrane valves, and wherein each of said membrane valves comprise a tubular housing made of material not conducting electricity, separated into two sections by a suitable metal membrane, said membrane sealingly engaged with said housing, and having suitable lead wires connected to said membrane at opposite sides.

10. The apparatus of Claim 9 wherein said membrane valves comprise suitable charges deposited on said membranes and suitable ignition wires leading to said charges, said charges capable of destructing said membranes when ignited through said ignition wires.

11. The apparatus of Claim 8 wherein said distributing means further comprise a suitable power switch located in and rotating with said hub of said fan, said power switch capable of directing required electrical impulses to said blade valves of said blades designated to receive said balancing fluid for opening of said blade valves when instructed by said control means.

12. The apparatus of Claim 8 wherein said delivery means comprise: a receiver for holding said balancing fluid; a delivery line for delivery of said balancing fluid from said receiver to said distributing means; and receiver transfer means for transfer of said balancing fluid from said receiver to said delivery line.

13. The apparatus of Claim 12 wherein said delivery line has an inlet end begining at said receiver, and an outlet end extending through said circular opening in one of, and positioned between, said axially spaced disks of said tire shaped ring.

14. The apparatus of Claim 13 wherein said receiver transfer means comprise a valve positioned between said receiver and said inlet end of said delivery line.

15. The apparatus of Claim 13 wherein said receiver transfer means comprise a pump positioned between said receiver and said inlet end of said delivery line.

16. A method for balancing of a fan of a turbofan jet engine after said fan develops an imbalance following the loss of a blade, said method comprising the steps of: detecting said imbalance of said fan; calculating the amount and location of said imbalance in said fan; designating the blades of said fan that must receive a balancing fluid in their cavities to balance said fan; and balancing said fan by transferring said balancing fluid into said cavities of said designated blades.

17. The method of Claim 16 wherein said method includes the additional steps of communication via radio means between a stationary computer and a rotating computer that rotates with said fan.

18. The method of Claim 17 wherein said method includes the additional step of identifying the lost blade, and wherein said step of designating the blades of said fan that must receive said balancing fluid in said cavities to balance said fan includes designating the blades that are located on both sides of and adjacent to the place of said lost blade.

19. The method of Claim 16 wherein said method includes the additional steps of confirming that said designated blades of said fan that must receive said balancing fluid in said cavities are present in said fan by analyzing signals from strain gauges.

20. The method of Claim 16 wherein said method includes the additional steps of confirming that said designated blades of said fan that must receive said balancing fluid in said cavities have their tips intact by analyzing signals from an optical sensor.

21. The method of Claim 18 wherein said step of balancing said fan comprises the steps of: activating a power switch to open blade valves connected to said designated blades; checking whether all blade valves connected to said designated blades have been opened; and further checking whether all blade valves connected to the blades of said fan that are not designated to receive said balancing fluid are closed; metering of said balancing fluid from a receiver of said balancing fluid into a delivery line, and delivering of said balancing fluid through an outlet end of said delivery line into a tire shaped ring attached to and rotating with said fan; and forcing by the centrifugal force of said balancing fluid from the peripheral section of said tire shaped ring through said opened blade valves into said cavities of said designated blades.

22. The method of Claim 21 wherein said method comprises a step of calculating the quantity of said balancing fluid required for said balancing of said fan, and wherein said balancing of said fan is done in separate steps, each of said separate steps including transfer into said designated blades of a fraction of said quantity of said balancing fluid required for said balancing of said fan, each of said transfers followed by checking whether a proper balancing is taking place, until said balancing of said fan is completed.

23. The method of Claim 18 wherein said step of balancing said fan comprises the steps of: metering of said balancing fluid from a receiver of said balancing fluid into a delivery line, and delivering of said balancing fluid through an outlet end of said delivery line into a tire shaped ring attached to and rotating with said fan; activating a power switch to open at least one of blade valves connected to said designated blades; and forcing by the centrifugal force of said balancing fluid from the peripheral section of said tire shaped ring through said opened blade valves into said cavities of said designated blades.

24. The method of Claim 23 wherein said method comprises a step of calculating the quantity of said balancing fluid required for said balancing of said fan, and wherein said balancing of said fan is done in separate steps, each of said separate steps including transfer into said designated blades of a fraction of said quantity of said balancing fluid required for said balancing of said fan, each of said transfers followed by checking whether a proper balancing is taking place, until said balancing of said fan is completed.

25. An apparatus for transfer of a fluid from a stationary receiver into cavities of blades of a rotating fan on a turbofan jet engine, said blades having passageways connecting said cavities with outside of said blades at the ends of said blades adjacent to a hub of said fan, said apparatus comprising: a tire shaped ring comprising two axially spaced disks, at least one of said axially spaced disks having a circular opening in the center, both of said axially spaced disks having an outside peripheral edge, said axially spaced disks sealingly connected on said outside peripheral edges in forming said tire shaped ring and a peripheral section of said tire shaped ring, said tire shaped ring attached to and rotating with said hub of said fan; at least one remotely operated blade valve for each of said blades of said fan, each of said blade valves connecting the inside of said peripheral section of said tire shaped ring with said passageway leading into said cavity of its blade; and delivery means for delivery of said fluid from said stationary receiver to said tire shaped ring.

26. The apparatus of Claim 25 wherein said fluid is a balancing fluid, and wherein said apparatus is a balancing apparatus for balancing of said fan after said fan develops an imbalance after losing a blade, said apparatus further comprising control means for: monitoring the operation of said fan and detecting and analyzing said imbalance; designating certain of said blades to receive said balancing fluid in said cavities to balance said fan; and controling said balancing of said fan.

27. The apparatus of Claim 26 wherein said control means comprise stationary control means that comprise a suitable stationary computer, and wherein said control means further comprise rotating control means that rotate with said fan and comprise a suitable rotating computer.

28. The apparatus of Claim 27 wherein said stationary computer and said rotating computer communicate via radio means, wherein said radio means comprise a stationary radio apparatus and a rotating radio apparatus that rotate with said fan, wherein said stationary radio apparatus comprises a radio transmitter-receiver connected to said stationary computer and at least one stationary antenna, and wherein said rotating radio apparatus comprises a radio transmitter-receiver connected to said rotating computer and at least one rotating antenna, said stationary antenna and said rotating antenna positioned as needed for communication between said stationary radio apparatus and said rotating radio apparatus.

29. The apparatus of Claim 28 wherein said stationary control means further comprise a vibration monitor for monitoring vibration of said fan during its operation, and for detecting and analyzing said imbalance.

30. The apparatus of Claim 28 wherein said rotating control means further comprise suitable strain gauges, positioned on said blades adjacent to said hub of said fan, for monitoring the presence of said blades in said fan during its operation.

31. The apparatus of Claim 28 wherein said blades have tips remote from said hub of said fan, and wherein said stationary control means further comprise a suitable optical sensor, positioned in front of said tips, for monitoring the presence of said tips of said blades in said fan during its operation.

32. The apparatus of Claim 25 wherein said remotely operated blade valves are electrically operated membrane valves, and wherein each of said membrane valves comprises a tubular housing made of material not conducting electricity, separated into two sections by a suitable metal membrane, said membrane sealingly engaged with said housing, and having suitable lead wires connected to said membrane at opposite sides.

33. The apparatus of Claim 32 wherein said membrane valves comprise suitable charges deposited on said membranes and suitable ignition wires leading to said charges, said charges capable of destructing said membranes when ignited through said ignition wires.

34. The apparatus of Claim 26 wherein said apparatus further comprises a suitable power switch located in and rotating with said hub of said fan, said power switch capable of directing required electrical impulses to said blade valves of said blades designated to receive said balancing fluid for opening of said blade valves when instructed by said control means.

35. The apparatus of Claim 26 wherein said delivery means comprise: a delivery line for delivery of said balancing fluid from said stationary receiver to said tire shaped disk; and receiver transfer means for transfer of said balancing fluid from said stationary receiver to said delivery line.

36. The apparatus of Claim 35 wherein said delivery line has an inlet end begining at said stationary receiver, and an outlet end extending through said circular opening in one of, and positioned between, said axially spaced disks of said tire shaped ring.

37. The apparatus of Claim 36 wherein said receiver transfer means comprise a valve positioned between said stationary receiver and said inlet end of said delivery line.

38. The apparatus of Claim 36 wherein said receiver transfer means comprise a pump positioned between said stationary receiver and said inlet end of said delivery line.

39. A method for transfer of a fluid from a stationary receiver into cavities of blades of a rotating fan on a turbofan jet engine, said method comprising the steps of: opening blade valves located between an inside peripheral section of a tire shaped ring and passageways leading into said cavities of said blades of said fan; delivering of said fluid from said stationary receiver into said tire shaped ring; and distributing said fluid with centrifugal force from said inside peripheral section of said tire shaped ring through said opened blade valves into said cavities of said blades of said fan.

40. A method for transfer of a fluid from a stationary receiver into cavities of blades of a rotating fan on a turbofan jet engine, said method comprising the steps of: delivering of said fluid from said stationary receiver into a tire shaped ring; opening blade valves located between an inside peripheral section of said tire shaped ring and passageways leading into said cavities of said blades of said fan; and distributing said fluid with centrifugal force from said inside peripheral section of said tire shaped ring through said opened blade valves into said cavities of said blades of said fan.

41. An apparatus for balancing of a fan on a turbofan jet engine substantially as described herein with reference to Figures 1 through 4 of the accompanying drawings.

42. A method for balancing of a fan on a turbofan jet engine substantially as described herein with reference to Figures 1 through 4 of the accompanying drawings.