Gas and liquid contact apparatus – Contact devices – Rotating
Reexamination Certificate
2000-01-27
2001-08-21
Bushey, C. Scott (Department: 1724)
Gas and liquid contact apparatus
Contact devices
Rotating
C261S120000, C210S219000, C210S242200
Reexamination Certificate
active
06276670
ABSTRACT:
FIELD OF THE INVENTION
This invention concerns an apparatus which is used for the aeration and/or mixing of water, in particular waste water.
BACKGROUND OF THE INVENTION
Apparatus for the aeration of water comprising a power source which drives a shaft to which a mixing device is affixed are well known, as can be seen from the Belgian patent 893.687.
European patent 0.366.644 describes this type of aerator in a form which can also be used as a mixer, whereby the power source is secured to a structure comprising two floats positioned one on top of the other and whereby the lower float can be immersed by the introduction of ballast.
The power source drives a helical propelling device which can operate in both directions of rotation. This apparatus can be used as an aerator when the top float is positioned above the surface of the water (The unit is then actually floating on the bottom float). If the apparatus floats on the top float and the direction of rotation is reversed, this apparatus can be used as a mixer.
Because of the twin floats and the associated manufacturing and operation costs there is a pressing need for a simpler apparatus which can be used both as a mixer and as an aerator.
A detailed investigation has been carried out to find an as simple apparatus design as possible, starting from a conventional mixer and from the apparatus described in EP 0.366.644, in which all the components have undergone an in-depth analysis and in which all possible parameters of each component have been studied during usage.
SUMMARY OF THE INVENTION
Surprisingly it was found that such an apparatus can be simply constructed if the following elements are employed correctly:
1. it is necessary for the power source to drive a shaft, to which a propelling device is secured, which can operate in both directions, in order to mix efficiently on the one hand, and to aerate efficiently on the other;
2. the propelling device must be helical;
3. the propelling device must be located completely below the surface of the water;
4. on the shaft, above the propelling device, at least partly below the surface of the water, an additional circulation element must be secured, which creates a water flow in the opposite direction to the movement generated by the propelling device.
In the text which follows “mixing” shall mean that the water is displaced from an area in a shallower position to an area in a deeper position; “aeration” shall mean that water is dispersed across the surface of the water or that a water-air mixture is displaced from the surface of the water to an area in a deeper position.
In a first aspect the invention therefore comprises an apparatus which can be used both as a mixer and as an aerator and which comprises a power source which drives a shaft upon which a helical propelling device is affixed, whereby the power source can drive the propelling device in both directions of rotation, characterized in that the propelling device is affixed to the shaft below the surface of the water and that above the propelling device, but at least partly below the surface of the water, an additional circulation element is affixed to the shaft which makes the water move in the opposite direction to the movement generated by the propelling device.
In a second aspect the invention comprises a method of operating the apparatus.
The propelling device should preferably be affixed to the shaft below the surface of the water at a distance from the surface of the water which is such that, as a function of the speed of rotation and the dimensioning of the propelling device, the distance between the top edge of the propelling device and the surface of the water is sufficiently great to prevent air being sucked in if the propelling device is operating in mixing mode, but does allow the water which is pumped up to be dispersed across the surface of the water or the air sucked in to be driven into the water if the propelling device is operating in aeration mode.
The correct position of the propelling device may be determined by the man skilled in the art whereby he may also often take into account, for example, the composition of the waste water, the depth of the basins, and also the other components with which the apparatus is fitted, some examples of which are described below.
The correct position may also be determined as a function of the use to which the apparatus is put. If, for example, an apparatus is desired which will preferably be used as a mixer, the indication can be to position the propelling device as deeply as possible in the water, although still allowing aeration to take place (in the aeration phase). On the other hand, when the apparatus is used predominantly as an aerator the propelling device can be positioned as closely as possible to the surface of the water while still allowing sufficient mixing to take place (in mixing mode).
The additional circulation element can be in the form of a plate, possibly corrugated or otherwise folded, but must impart a movement to the water which is in the opposite direction to the movement brought about by the propelling device. By preference the circulation element is in the shape of a blade.
The circulation element also allows the vortex above the propelling device to be broken up; this vortex occurs if the propelling device operates in the mixing direction thus propelling water downwards. Because the circulation element can impart a slight upwards movement and then a toroidal movement to the water not only the vortex is broken up but foam and other floating elements—which are usually present on the surface of the water—are sucked in and propelled downwards with the water circulation.
By preference the circulation element will be positioned below the surface of the water, possibly right against the surface of the water, which also prevents air being sucked into the water during the mixing movement.
In order to improve the flow of the water it can be advantageous to fit the apparatus with a deflector which will preferably be conical in shape. This deflector can be affixed to the apparatus above the circulation element and then preferably near or just above the surface of the water. The deflector can also be positioned below the surface of the water, for example between the propelling device and the circulation element.
The deflector can be affixed to the shaft if it also has to rotate, but can also be secured in a fixed position to a structural element.
In accordance with a beneficial design form, the propelling device is at least in part surrounded by a pump housing, which is positioned fully below the surface of the water. The pump housing will preferably be cylindrical in shape and have a circular section, whereby it can be advantageous if on the top side and/or the underside an outwardly fanning conical inlet or outlet is positioned.
Although unnecessary, the best effect is obtained when a volute or pump housing surrounds the propelling device over the full height.
Further, the pump housing can be provided with stabilizers, water guides and other known parts, whereby these elements can also play a role in the structure of the apparatus.
The power source can be positioned either above or below the surface of the water. Above the surface of the water the power source can be suspended on a structure or can be carried on floats. If the power source is carried on one or more floats it is useful to avoid that the floats influence the movement of the water caused by the propelling device.
REFERENCES:
patent: 2072944 (1937-03-01), Durdin, III
patent: 2174147 (1939-09-01), Unger, Jr.
patent: 2346366 (1944-04-01), Durdin, III
patent: 3416729 (1968-12-01), Ravitts et al.
patent: 3911065 (1975-10-01), Martin et al.
patent: 3975469 (1976-08-01), Fuchs
patent: 4468358 (1984-08-01), Haegeman
patent: 4540528 (1985-09-01), Haegeman
patent: 5021154 (1991-06-01), Haegeman
patent: 5707562 (1998-01-01), Karliner
patent: 5744072 (1998-04-01), Karliner
patent: 0 366 644 (1990-05-01), None
patent: WO 99/01386 (1999-01-01), None
Aquasystems International N.V.
Bushey C. Scott
Merchant & Gould P.C.
LandOfFree
Combined mixer-aerator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Combined mixer-aerator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Combined mixer-aerator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2509784