Gas and liquid contact apparatus – Contact devices – Rotating
Patent
1998-03-20
2000-10-03
Simmons, David A.
Gas and liquid contact apparatus
Contact devices
Rotating
261 93, B01F 304
Patent
active
061261505
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention pertains to a device for introducing and dispersing a fluid in a liquid. More specifically, it relates to a submersible fluid mixing impeller for introducing and dispersing a fluid, such as a gas or liquid, into a liquid. Preferably, the device is used as an aerator for aerating liquid-solid organic waste mixtures in order to accelerate the decomposition of the organic matter.
BACKGROUND OF THE INVENTION
Submersible mixing impellers are known devices with a wide variety of applications for introducing a fluid, such as a gas or liquid, into the liquid in which the device is submerged. For example, they are used to draw air from the atmosphere into a liquid to aerate the liquid.
In the field of organic waste treatment, decomposition of organic matter, such as vegetable wastes and sewage, can be effected by introducing suitable bacteria into a tank containing a slurry of the organic matter in water, while aerating and mixing the slurry. Thorough aeration of the slurry, in the form of fine air bubbles dispersed throughout the slurry, accelerates such decomposition by providing ample oxygen to the bacteria.
Slurries of organic matter typically contain solid matter, namely the organic matter itself or trash such as wrapping materials, which are frequently made of plastic, that accompany the waste. To prevent blockages within the aerator, it is important that it function in a manner which does not draw the slurry into the aerator during the aeration process. It is also desirable for the aerator to draw sufficient air into itself for aeration of the slurry by the simple rotation of the aerator, without the need for any external pump to supply air to the aerator. It is also desirable for the aerator to disperse the drawn air into the slurry as fine bubbles. A need therefore exists for an improved aerator for use in aerating waste slurries.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a rotatable mixing impeller to be submersed in a liquid, the device having peripheral blades extending outwardly from the body of the device with fluid exit ports immediately rearward of such blades which are shielded by the blades as the device rotates in the liquid so that the partial vacuum produced by the rotating blades prevents liquid from entering the ports.
The mixing impellers of the present invention are of the type that are submerged in liquid at the end of a hollow shaft and draw gas or liquid down the shaft as they are rotated, by means of the vacuum drawn by the device. They have a rotatable body which ejects the fluid drawn down the hollow shaft of the device into the liquid in which they are submerged through ports at the circumference of the body, said ports being positioned immediately rearward of outwardly projecting, rearwardly inclined blades. The inventor has found the devices of the present invention, when used as aerators, highly effective in aerating liquid-solid slurries. It is believed that the effectiveness is due to the creation of a strong partial vacuum immediately behind the projecting portion of the blades as the aerator rotates, producing a pocket of water vapor into which air is ejected through the air exit ports before dispersing in the body of the liquid.
According to one aspect of the invention, there is provided an aerator to be submerged in a liquid for introducing and dispersing air in the liquid. The aerator has a lower body, an upper body and a plurality of blades disposed between the upper and lower bodies. The lower and upper bodies are generally circular in horizontal cross-section and are rotatable, together with the blades, as a unit. The blades are spaced apart from each other and have a portion which projects outwardly and rearwardly with respect to the intended direction of rotation of the aerator. The upper body has an axial bore to engage with a rigid air conduit which is open to the atmosphere at its intake end. The axial bore interconnects with spaces between the blades which form air exit conduits. The aerator is
REFERENCES:
patent: 1726125 (1929-08-01), Rowand
patent: 2609189 (1952-09-01), Dering
patent: 2944802 (1960-07-01), Damen
patent: 3796417 (1974-03-01), Kaelin
patent: 3864438 (1975-02-01), Nagahama
patent: 3875279 (1975-04-01), Kaelin
patent: 4018859 (1977-04-01), Muller
patent: 4283357 (1981-08-01), Sidery
patent: 4426068 (1984-01-01), Gimond et al.
patent: 5013490 (1991-05-01), Tanimoto et al.
patent: 5160459 (1992-11-01), Guarnaschelli et al.
patent: 5660766 (1997-08-01), Van Dyk
patent: 5925293 (1999-07-01), Howk
Copy of the International Search Report for PCT/CA96/00628.
Copy of the International Search Report for PCT/CA96/00628, Oct. 21, 1997.
Hopkins Robert A.
Simmons David A.
LandOfFree
Submersible mixing impeller does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Submersible mixing impeller, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Submersible mixing impeller will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-187594