Patent ID: 12187433

DETAILED DESCRIPTION

FIGS.1-9pertain to a vent system10for a fluid dispersion tank12of an aircraft14, wherein aircraft14is used for dispersing a fluid16or other flowable product while in-flight. A gate valve assembly18at the bottom of tank12includes at least one gate20that opens to release fluid16from tank12. Gate20is movable between a closed position (FIGS.1,4,5,7,11and12) to retain fluid16and an open position (FIGS.2,6,8,9, and10) to release fluid16. When gate20opens, it releases fluid16from tank12while vent system10prevents a detrimental vacuum from developing within tank12. The released fluid16is dispersed along the aircraft's trailing flight path. Such a system is particularly suited for agricultural and firefighting purposes.

The term, “aircraft” refers to any flying machine. Some examples of aircraft14include an aerial crop duster, air tanker, an airplane, a helicopter, an Air Tractor AT402, an Air Tractor AT502, an Air Tractor AT602, an Air Tractor AT802A, an Air Tractor AT802F, a Thrush aircraft, and a Dromodier aircraft.

The term, “fluid” refers to any product or material that can flow. Some examples of fluid16include a liquid, granules, particles, seed, powder, water, chemical mixtures, fertilizer, pesticide, and fire retardant.

The term, “tank” refers to any hollow structure for containing a fluid. Some examples of tank12include a vessel, a hopper, a container, a receptacle, etc. In the illustrated examples, tank12defines a chamber22for containing fluid16. In some examples, tank12is filled with fluid16through a fill valve112at a port24on either tank12or gate assembly18.

The term, “gate” refers to any member that can be moved relative to an opening to vary the flow of a fluid through the opening or selectively stop (or substantially stop) the flow. Some example gates include plates, plugs, flaps, diaphragms, etc. Some example modes of gate movement include translating, pivoting, expanding, contracting, bending, and various combinations thereof. Some examples of gate assembly18include those disclosed in U.S. Pat. No. 11,046,433 and U.S. patent application Ser. Nos. 17/202,577 and 17/386,721; all of which are specifically incorporated herein by reference. In some examples, gate20is a 5-inch, 7.5-inch or 10-inch wide gate provided by Transland of Wichita Falls, Texas. In some examples, gate20is one of a series of gates in a gate assembly, wherein the gates open and close in unison. Gate20and gate assembly18are schematically illustrated inFIGS.5-12.

For describing physical orientations and relative positions, certain components of vent system10are described herein with reference to known orthogonal axes of aircraft14, as shown inFIG.3.FIG.3shows aircraft14comprising a nose26, a tail28, a cockpit30, and a windshield32. Aircraft14defines a roll axis34, a pitch axis36, and a yaw axis38. Aircraft14extends lengthwise along roll axis34in a forward direction40from tail28to nose26. Windshield32faces generally in forward direction40. Aircraft14extends laterally widthwise along pitch axis36. Aircraft14extends along yaw axis38in an upward direction42from a lower portion44of aircraft14to an upper portion46of aircraft14. Cockpit30is between tail28and nose26with respect to roll axis34. Roll axis34, yaw axis38, and pitch axis36lie perpendicular to each other.

In some examples, vent system10comprises a vent48defining an aperture50through tank12, a vent member52for selectively opening and blocking aperture50, a vent closure spring54for urging vent member52to a closed sealed position (FIGS.1,4,5, and7), a scoop56extending at least partially over aperture50, and a slender member58coupling vent member52to gate valve assembly18. The term, “vent member” refers to any structure for selectively blocking and unblocking an aperture. A few examples of vent member52include a plate, a disc, a plug, a diaphragm, a ball, a flap, a cone, a partially spherical body, etc. Some example modes of vent member movement include translating, pivoting, expanding, contracting, bending, and various combinations thereof.

Some examples of vent48comprise an inlet well60extending down into the tank's chamber22toward the vent's aperture50. Inlet well60has a brim62at an upper surface64of tank12. Brim62is the outer periphery of inlet-well60. In some examples of vent48, a lower end60′ of inlet-well60defines aperture50between the tank's chamber22and an outside atmosphere66surrounding aircraft14. In some examples, inlet-well60includes an upstream surface68and a downstream surface70. Aperture50and downstream surface70are behind upstream surface68with respect to the forward direction40along roll axis34. In some examples, upstream surface68extends downward from brim62toward aperture50, and downstream surface70extends upward from aperture50. In some examples, inlet well60is 3D printed and is comprised of carbon fiber reinforced polypropylene.

In some examples, upstream surface68is sloped more gradually than downstream surface70, as viewed along an imaginary plane72, wherein imaginary plane72is defined as intersecting a centerpoint74of aperture50and lying perpendicular to pitch axis36. In some examples, the aperture's centerpoint74is laterally centered relative to aircraft14and roll axis34. In other examples, the aperture's centerpoint74is laterally offset to the left or right of roll axis34. Some examples of vent system10include two vents48or48′ on either side of roll axis34. Some examples of vent system10include more than two vents48or48′.

In some examples, the gradual slope of upstream surface68promotes a beneficial Coanda effect, whereby upstream surface68tends to draw air to itself and thereby effectively direct that air down toward aperture50. In some examples, upstream surface68curves smoothly along imaginary plane72to gradually direct the airflow downward. In some examples, upstream surface68is substantially linear along imaginary plane72to simplify manufacturing of vent48. In some examples, upstream surface68lies at an acute angle76of less than 45 degrees to roll axis34to promote the Coanda effect.

Inlet-well48placing aperture50at a recessed elevation below the tank's upper surface64in combination with the Coanda effect enables vent48to draw an ample amount of air down through aperture50and into tank12without creating a prominent upward protrusion that could otherwise significantly obstruct a pilot's view. In some examples, however, a relatively low-profile scoop56can be added to increase the airflow through aperture50and to help shield windshield32from backsplash when vent48is open.

To minimize obstructing the pilot's view, some examples of scoop56extend only a certain height78above brim62, wherein certain height78is less than a well-depth80of inlet-well60. In some examples, well-depth80is preferably at least one inch lower than brim62to realize the benefit of a recessed vent. In some examples, the certain height78is less than three inches to avoid creating a significant obstruction to the pilot's view. In some examples, the scoop's certain height78is less than two inches, and well-depth80is greater than two inches to provide a good compromise between vent inlet airflow and minimal obstruction to the pilot's view. In some examples, the scoop's height78is about 1.5 inches, and well-depth80is about three inches for best results. To realize at least a minimal benefit of aperture50being recessed, inlet-well60at aperture50is at least one inch lower than brim62. In some examples, as shown inFIG.10, a scoop56′ has a certain height78that is substantially equal to zero (i.e., scoop56′ is substantially flush with brim62).

To further increase vent airflow while reducing backsplash, some examples of scoops56and56′ extend in forward direction40out over aperture50. With the addition of scoop56or56′, some backsplash of fluid16might collect in a lower rear area82of vent-well60. In some examples, a drain tube84can be used for draining this collection of fluid16.

In some examples, drain tube84has an inlet86and an outlet88. Inlet86, in some examples, is in fluid communication with inlet-well60at a point in lower rear area82above aperture50and below brim62. In some examples, the drain tube's outlet88is below the tube's inlet86and below aperture50. In some examples, drainage of fluid16through drain tube84is directed back into tank12, directed down into a separate waste collection tank, or simply released into the surrounding atmosphere66. The term, “tube” refers to any fluid passageway. Some examples of a tube include a pipe, a hose, a conduit, a drilled hole, a channel, a gutter, and various combinations thereof.

In some examples, to reduce assembly costs and avoid leakage points, inlet-well60is integrally formed seamlessly in the tank's upper surface64. In such examples, inlet-well60and the tank's upper surface64are both made of the same material. In some examples, the tank's upper surface64is part of a lid that is hinged to the rest of tank12, whereby the hinged lid provides access to chamber22.

In some examples, tank12adjoins a cowl90of aircraft14. In some examples, cowl90is comprised of a first material (e.g., aluminum alloy), tank12and inlet-well60are each comprised of a second material (e.g., a polymer, fiberglass, or some other composite), and the first material is different than the second material. The two materials being different from each other allow the use of optimal materials each being uniquely suitable for an aircraft cowl and a tank's wall.

In some examples, vent closure spring54urges vent member52to its closed position. Vent closure spring54is schematically illustrated to represent any resilient member capable of urging vent member52to its closed position. Some examples of vent closure spring54include a torsion spring, a compression spring, an extensions spring, a leaf spring, a constant force spring, an elastic cord, an elastic strap, a pneumatic spring, a bellows, etc. In some examples, a certain level of vacuum (e.g., −0.5 psig) in chamber22overcomes vent closure spring54and thereby forces vent member52to its open position. A vacuum of −0.5 psig, however, can delay the release of fluid16out from within tank12.

To overcome this problem, some examples of vent system10include slender member58. The term, “slender member” refers to any elongate structure having a length that is at least ten times greater than its width. Some examples of slender member58are rigid. Other examples of slender member58are more flexible or pliable. Some examples of slender member58include a cable, a chain, a nylon strap, an elastic strap, an extension spring, a wire, a rope, a cord, a rod, a bar, a linkage, a linkage assembly, a tube, and various combinations thereof.

In some examples, slender member58couples vent member52to gate valve assembly18such that gate20moving between the closed position and the open position causes vent member52to move respectively between its sealed position and the unsealed position. In some examples, vent closure spring54holds vent member52at the sealed position when gate20is in its closed position. In some examples, slender member58overpowers vent closure spring54to force vent member52to its unsealed position when gate20is in the open position.

In some examples, when gate20is in the closed position, slender member58is slack (FIGS.5and7), which allows vent closure spring54to close vent member52without appreciable resistance from slender member58. In some examples, when gate20is in the open position, slender member58is taut (FIGS.6,8, and9) and forces vent member52to its unsealed position.

It should be appreciated by those of ordinary skill in the art that points92and94to which slender member58respectively connects to vent member52and gate valve assembly18can be at any suitable locations. In some examples, point92is on a lug96extending from vent member52. In some examples, point94is on a lug98extending from gate20, as shown inFIGS.5,6,7, and8. In some examples, as shown inFIG.9, point94can be attached to a link100connecting gate20to a gate actuator102.

Gate actuator102is schematically illustrated to represent any means for powering the movement of gate20. Some examples of gate actuator102include a motor, a hydraulic cylinder, a gearbox, a linkage assembly, and various combinations thereof. In some examples, a linkage assembly, gears, or some other mechanism couples multiple gates20to gate actuator102, so the multiple gates20open and close in unison.

In some examples, vent system10includes two or more vents48, as shown inFIG.9. In some examples, vent system10includes a front vent48aand a rear vent48b. In some examples, each vent48aand48bare substantially identical to vent48. Vents48aand48bhave a strategic tandem arrangement such that an upper surface104of the front vent's scoop56utilizes the Coanda effect to direct air106into an inlet50of the rear vent48b. In some examples, rear vent48bcan capture backsplash that might escape front vent48a, thus minimizing the amount of backsplash that might otherwise reach windshield32.

In the example shown inFIGS.11and12an example vent member52′ in the form of a vertically translating plate and an example vent closure spring54′ is in the form of a compression spring. Vent closure spring54′ urges vent member52′ to its sealed position (FIG.11). When gate20opens, slender member58pulls vent member52′ to its unsealed position (FIG.12). In some examples one or more spokes110help position vent member52′ in a radial direction. In some examples, to achieve sufficient ventilating airflow, the vertical travel distance of vent member52′ is at least twenty percent of the vent member's outer diameter. In some examples, the vertical travel distance of vent member52′ is about 2.5 inches.

In addition or alternatively, some examples of vent system10have two modes of operation, e.g., a first mode and a second mode. Examples of first mode are shown inFIGS.13and14. Examples of second mode are shown inFIGS.2,6,8,9and10.

In some examples of the first mode, vent member52or52′ of vent48or48′ moves independent of gate20from the sealed position to the unsealed position in response to the chamber pressure (i.e., the air pressure in chamber22) decreasing a predetermined amount below the atmospheric pressure. In some examples, the predetermined amount is 0.8 psig below atmospheric pressure (i.e., −0.8 psig). So, in some examples, if the air pressure differential across vent member52or52′ reaches or exceeds 0.8 psig (at least 0.8 psig of vacuum in chamber22), then the pressure differential will open the vent. In some examples, the predetermined amount is between about 1.5 psig to 2 psig below atmospheric pressure.

Such a first mode of operation helps avoid collapsing or otherwise damaging tank12under certain adverse pressure conditions. For instance, in some cases, fill valve112or gate20might leak. The lost fluid16could create excessive vacuum in chamber22. In other cases, changes in elevation of aircraft14might create an adverse vacuum in chamber22.

As a means for preventing damagingly high vacuum from developing within chamber22, the first mode of operation allows vent member52and52′ to open independent of gate20. So, in the first mode, vent members52and52′ can move regardless of whether gate20is open or closed.

In the second mode, vent members52and52′ can move independent of the chamber pressure from the sealed position to the unsealed position in response to gate valve assembly10applying a predetermined amount of tension114to slender member58. The predetermined amount of tension114is that which is needed to overcome the force of vent closure spring54or54′.

The second mode allows vent members52and52′ to open even when there is no pressure differential between the air pressure in chamber22and the outside atmosphere. The second mode of operation allows aircraft14to release fluid16at a maximum fluid flow rate, as vent system10does not require a vacuum or −0.5 psig in chamber22in order to function properly.

To prevent accidentally damaging vent system10, some examples of slender member58include a tension-limiting spring116(e.g., an extension spring). Tension-limiting spring116can be installed anywhere along the length of slender member58. If for some reason slender member58tries to exert excessive pulling force on vent member52or52′, tension-limiting spring116will yield (resiliently extend) to limit the slender member's pulling force (tension114). Tension-limiting spring116, for example, prevents an installer or mechanic from adjusting slender member58so tightly that it damages vent system10. Under normal operation, tension-limiting spring116remains unextended regardless of whether vent system10is open or closed.

Although certain example methods, apparatus and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the claims of this patent.