Fluid device using coanda effect

Claim 2

A nozzle for effecting movement of a secondary fluid by a pressurized primary fluid comprising means forming a passageway having aN entrance and an exhaust and an intermediate throat, said throat being the smallest cross-sectional area of the passageway nearest the entrance, a slit communicating with the passageway between the throat and the entrance, said throat and slit each having a diameter and being axially spaced along the passageway, said entrance being open to the secondary fluid and a source of pressurized primary fluid being adapted to be connected to the slit whereby flow of primary fluid through the slit induces flow of secondary fluid into and through the passageway with both fluids being discharged from the exhaust, the improvement comprising said slit being located closely adjacent said throat with the ratio of the throat diameter divided by the linear axial distance between the throat and slit being greater than essentially 3 and with the ratio of the throat diameter to slit diameter being less than 1.5.

Claim 3

The invention as defined in claim 1, in which the range of the ratio of the throat diameter to slit diameter is 1.1 to 1.3.

Claim 4

The invention as defined in claim 1 in which the angle of discharge between the slit and the axis of the passageway is greater than essentially 60* and is determined by the complement of the tangent of the angle of the ratio of the difference between the throat and slit radii divided by the linear axial distance between the throat and slit.

Claim 5

The invention as defined in claim 1 in which the entrance has an entrance end and in which the ratio of the linear axial distances from the throat to the entrance end and the throat to the slit is in the range of 2 to 4.

Claim 6

A fluid device for inducing movement of a secondary fluid by the use of an ejected primary fluid with the discharge being a combination of the two fluids comprising a first and a second surface, said surfaces being aligned and having one end common to define a throat, a common reference with said throat being the nearest part of the surfaces to the reference, the first surface forming an exhaust and diverging from the reference as it recedes from the throat and being shaped to effect laminar flow of fluid thereover, said second surface forming an entrance and diverging from the reference as it progresses from the throat in the opposite direction to the receding of the first surface and having its other end form an entrance end that is positioned in a supply of secondary fluid, a slit formed through the second surface and means adapted to connect the slit to a source of primary fluid under pressure so that a flow of primary fluid under pressure through the slit induces a flow of secondary fluid from the entrance along a path past the slit and throat and the first surface to have the combined fluids discharge from the first surface, the improvement comprising said throat having essentially no length along the path, the slit is just slightly further from the reference than the throat is from the reference and is located closely adjacent the throat with the ratio of twice the distance from the reference to the throat divided by the linear distance along the reference between the throat and slit being greater than essentially 3 and with the ratio of the distance from the reference to the slit divided by the distance from the reference to the throat being less than 1.5.

Claim 7

A fluid device for inducing movement of a secondary fluid by the use of an ejected primary fluid with the discharge being a combination of the two fluids comprising a first and a second surface, said surfaces being aligned and having one end common to define a throat, a common reference with said throat being the nearest part of the surfaces to the reference, the first surface forming an exhaust and diverging from the reference as it recedes from the throat and being shaped to effect laminar flow of fluid thereover, said second surface forming an entrance and diverging from the reference as it progresses from the throat in the opposite direction to the receding of the first surface and having its other end form an entrance end that is positioned in a supply of secondary fluid, a slit formed through the second surface and means adapted to connect the slit to a source of primary fluid under pressure so that a flow of primary fluid under pressure through the slit induces a flow of secondary fluid from the entrance along a path past the slit and throat and the first surface to have the combined fluids discharge from the first surface, the improvement comprising said throat having essentially no length along the path, the slit is just slightly further from the reference than the throat is from the reference and is located closely adjacent the throat with the ratio of twice the distance from the reference to the throat divided by the linear distance along the reference between the throat and slit being greater than essentially 3 and with the ratio of the distance from the reference to the slit divided by the distance from the reference to the throat being less than 1.5.