# US 2011/0036781 A1 · Filter assembly for fuel supply to actuators and fuel control system of aircraft engine and method

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- Number: US 2011/0036781 A1
- Document ID: US20110036781A1
- Status: Published application
- Kind: A1
- Application number: 11/935,900
- Filed: 2007-11-06
- Published: 2011-02-17
- Earliest claimed: 2006-11-06
- Assignees: Argo-Tech Corporation
- Inventors: Martin A. Clements; Robert Nyzen; John P. Ogger; William T. Flynn
- Web page: https://patentgrep.com/patent/US20110036781A1

## CPC

- B01D 29/25: open-ended {the arrival of the mixture to be filtered and the discharge of the concentrated mixture are situated on both opposite sides of the filtering element}
- B01D 29/118: {open-ended}
- B01D 29/904: {directing the mixture to be filtered on the filtering element in a manner to clean the filter continuously (B01D29/115, B01D29/118, B01D29/17, B01D29/25, B01D29/336, B01D29/356, B01D29/902, B01D29/908 take precedence)}
- B01D 37/00: Processes of filtration (processes specially adapted for filtering gases B01D46/00)
- F02C 7/22: Fuel supply systems
- F02M 37/38: with regeneration means
- F05D 2260/601: using an ejector or a jet pump
- F05D 2260/607: Preventing clogging or obstruction of flow paths by dirt, dust, or foreign particles
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A filter assembly for a fuel delivery system for actuators and fuel control system of an aircraft engine includes a wash flow filter. Fuel flow velocity is increased through the filter through use of a recirculating passage that is effectively achieved through use of an ejector pump. A portion of the pressurized fuel delivered by the main fuel pump is diverted and serves as a motive fluid that scavenges unfiltered flow from downstream of the filter and recirculates or discharges the recirculated flow to an inlet of the filter. This provides increased velocity to maintain sufficient washing of the filter openings.

## Claims

### Claim 1

A wash flow filter assembly comprising:
a pump for pressurizing associated fuel flow and a valve downstream of the pump;
a wash flow filter downstream of the valve having an inlet and a first outlet through which unfiltered fuel flow is delivered, and a second outlet through which filtered fuel flow is delivered; and
a fuel flow velocity increasing assembly that maintains a desired velocity of fuel flow to the first outlet of the wash flow filter during low flow conditions including a passage recirculating a portion of fuel flow from the first outlet to the inlet, an ejector pump for increasing fuel flow velocity from the inlet to the first outlet of the wash flow filter, wherein the ejector pump receives flow from the pump at a location upstream of the valve to provide a motive flow to the ejector pump, and recirculates flow from downstream of the filter to a location at least partially upstream of the filter.

### Claim 2 (depends on 1)

The wash flow filter assembly of claim 1 wherein the motive flow of the ejector pump branches from downstream of the pump and upstream of the valve.

### Claim 3 (depends on 2)

The wash flow filter assembly of claim 2 wherein a recirculation inlet of the ejector pump receives through flow from the first outlet.

### Claim 4 (depends on 3)

The wash flow filter assembly of claim 3 wherein a recirculation outlet introduces flow from the ejector pump to the inlet.

### Claim 5 (depends on 4)

The wash flow filter assembly of claim 4 wherein the recirculation outlet introduces flow downstream of the valve.

### Claim 6 (depends on 1)

The wash flow filter assembly of claim 1 wherein a recirculation inlet of the ejector pump receives through flow from the first outlet.

### Claim 7 (depends on 6)

The wash flow filter assembly of claim 6 wherein the ejector pump receives through flow from upstream of the associated fuel control system.

### Claim 8 (depends on 1)

The wash flow filter assembly of claim 1 wherein a recirculation outlet introduces flow from the ejector pump at least partially upstream of the filter and downstream of the valve.

### Claim 9 (depends on 1)

The wash flow filter assembly of claim 1 wherein a recirculation inlet of the ejector pump receives through flow from the first outlet and upstream of the associated fuel control system.

### Claim 10

A method of filtering fuel flow to associated actuators and an associated fuel control system of an associated aircraft engine, comprising:
delivering fuel from a pump to an inlet of a wash flow filter assembly;
passing a first portion of the fuel flow to a first outlet of the filter assembly that operatively communicates with the associated fuel control system;
filtering a second portion of the fuel flow that proceeds to a second outlet of the filter assembly that operatively communicates with the associated actuators; and
increasing fuel flow velocity to maintain a desired velocity of fuel flow to the first outlet and effectively wash the filter assembly.

### Claim 11 (depends on 10)

The method of claim 10 comprising recirculating fuel flow from the first outlet to the inlet of the filter assembly.

### Claim 12 (depends on 11)

The method of claim 11 comprising using a portion of the fuel delivery to scavenge fuel from the first outlet and pressurize the recirculated fuel delivered to the filter assembly inlet.

### Claim 13 (depends on 10)

The method of claim 10 wherein the fuel flow velocity increasing step includes increasing the velocity of wash fuel flow to the first outlet of the filter assembly in response to increased pump flow.

### Claim 14 (depends on 10)

The method of claim 10 further comprising providing a biased poppet between the inlet and the first outlet.

### Claim 15 (depends on 14)

The method of claim 14 further comprising recirculating a portion of the fuel flow directed toward the first outlet to a region at least partially upstream of the second outlet.

### Claim 16 (depends on 15)

The method of claim 15 further comprising providing a passage through the poppet such that recirculating flow increases in response to increased flow through the filter assembly.

### Claim 17

A wash flow filter assembly for use in an associated aircraft engine, the assembly comprising:
a housing having an inlet and first and second outlets in fluid communication with one another;
a filter disposed along a fluid path between the inlet and the first outlet whereby filtered material separated by the filter is washed therefrom and carried by throughflow fluid to the first outlet;
the second outlet located downstream of the filter from the inlet and receiving filtered fluid flow therefrom;
a movable poppet disposed along the fluid path for varying the amount of flow along the fluid path; and
a recirculating passage for redirecting at least a portion of throughflow from a downstream location to an upstream location along the fluid path.

### Claim 18 (depends on 17)

The assembly of claim 17 further comprising a biasing member for urging the poppet toward a first position.

### Claim 19 (depends on 17)

The assembly of claim 17 further comprising a guide member for controlling movement of the poppet.

### Claim 20 (depends on 17)

The assembly of claim 17 wherein the poppet is urged toward the inlet by a biasing spring, and the fluid path is generally an annular passage formed between the poppet and housing.

### Claim 21 (depends on 20)

The assembly of claim 20 wherein the filter is generally frustoconical.

### Claim 22 (depends on 17)

The assembly of claim 17 wherein the recirculating passage includes a passage though the poppet.

### Claim 23

A wash flow filter assembly comprising:
a wash flow filter having an inlet and a first outlet through which unfiltered fuel flow is delivered, and a second outlet through which filtered fuel flow is delivered; and
one of a nozzle and a poppet for maintaining a desired velocity of fuel flow to the first outlet of the wash flow filter during low flow conditions, at least one of the nozzle and the poppet including a biasing member that urges the at least one of the nozzle and poppet toward a first, low flow position.

### Claim 24 (depends on 23)

The wash flow filter assembly of claim 23 further comprising a recirculation passage through the poppet for recirculating a portion of the flow directed toward the first outlet toward the inlet.

### Claim 25 (depends on 24)

The wash flow filter assembly of claim 24 wherein the poppet includes an internal cavity that interconnects a downstream restriction with a recirculating opening.

### Claim 26 (depends on 24)

The wash flow filter assembly of claim 24 further comprising a venturi passage that communicates between the outlet and the internal cavity.

### Claim 27 (depends on 24)

The wash flow filter assembly of claim 24 wherein the recirculation passage includes elongated openings through the poppet.

### Claim 28 (depends on 27)

The wash flow filter assembly of claim 27 wherein the openings are angled relative to a longitudinal axis of the poppet.

### Claim 29 (depends on 23)

The wash flow filter assembly of claim 23 wherein the nozzle is fixed relative to the filter.

### Claim 30 (depends on 29)

The wash flow filter assembly of claim 29 wherein the nozzle includes a first passage that is normally open during low flow and a second passage that is restricted during low flow.

### Claim 31 (depends on 30)

The wash flow filter assembly of claim 30 wherein the biased poppet is urged to restrict communication between the inlet and second passage.

### Claim 32 (depends on 29)

The wash flow filter assembly of claim 29 wherein the nozzle directs fuel flow toward the filter.

### Claim 33 (depends on 23)

The wash flow filter assembly of claim 23 wherein the nozzle moves relative to the filter.

### Claim 34 (depends on 33)

The wash flow filter assembly of claim 33 wherein the nozzle is urged by the biasing member toward a first position directing fuel flow toward the filter.