A SUBMERSIBLE MIXER WITH OSCILLATING DEVICE

Abstract: The invention concerns a submersible mixer for mixing fluids being directed along a vertical guide. The mixer is so arranged that the reaction force from its propeller causes the mixer to oscillate between two extreme positions, thus obtaining a more sufficiant mixing of the liquid.

Description: This invention concerns a device for a mixer for mixing liquids, which device automatically changes the direction of the mixer to increase the liquid volume operated by the mixer making the mixing more effective. Such mixers are used for mixing liquids and suspensions of different kinds and may be placed in tanks in water courses etc. A submersible mixer comprises a driving unit such as an electric motor and a propeller built together into a unit which is normally arranged to be lowered into the liquid along a vertical guide. By help of this it is simple to hoist the mixer for service work. In order to be able to guide the mixing in different directions the mixer is normally turnable in the horizontal as well in the vertical plane and sometimes even the vertical guide is turnable. The guiding or controlling is carried out manually, but an automatic adjustment by help of an external driving source could occur. A manual guiding can of course not be continuous and a separate driving source means a considerable additional cost, especially at outdoor installations such as purification plants and means for preventing formation of ice. In order to obtain an automatically varying direction of a mixer without any need for an external energy source, it has been practised to use the force created by the mixer itself. Such a device is shown in DE-A-3136345. Here the reaction force from the mixer propeller is able to turn the mixer entirely around its guide. This known device has however the disadvantage, that the movement of the mixer will be very unstable and thus it is very difficult to obtain a correct mixing of the entire tank. According to the invention the reaction force from the mixer propeller is used to obtain a controlled turning of the mixer between two extreme positions. The invention is described more closely below with reference to the enclosed drawings which show an embodiment of the invention seen from above and from one side. In the drawings 1 stands for a mixer with a propeller 2 and a rack 3. 4 stands for a guide and 5 sliding means, 7 and 8 stopping means, 12 rudders, 13 spring means and 14 and 15 actuating means. According to the invention the mixer 1 is pivotedly attached to the vertical guide 4. In additon the mixer is provided with one or several rudders 12, placed in the current created by the mixer. The rudder or rudders are provided with springs 13, which direct them in two alternative inclinations. The function is described below. When the rudder 12 takes its one position, which deviates from the direction of the current created by the mixer, the reaction force F from the current will act on the rudder and turn the mixer to bring the jet away from the rudder surface. During the turning the rudder, which is mounted on the mixer, accompanies said turning movement and after a certain angle it contacts a fixed stopping means 8. The mixer continues its turning movement further until the rudder 12, influenced by the stopping means 8, changes its angle with regard to the current direction. At first it takes a position in parallel with the current and then a certain angle in the opposite direction. The changeover is facilitated by a spring 13, which is stretched when the rudder takes its middle position in parallel with the current. When the rudder 12 has taken its opposite angle position with regard to the current direction, the reaction force F from the propeller will act upon the rudder in the opposite direction. This turning will continue until the rudder, after a certain angle, comes into contact with another stopping means 7. Further turning means finally that the rudder changes its position again and a turning of the mixer in the opposite direction starts again. In this way an oscillating movement of the mixer is obtained, which movement takes place automatically and without the need of any external energy source. In order to secure the function and diminish the risk for disturbance in the current, there are preferably two rudders provided, one at each side of the propeller circumference. The two rudders will then alternatively be present within the current. They are, however, linked to each other such that they always turn in uniform. It is also possible to arrange one or several rigid rudders having directions such that the mixer always turn in one and the same direction thus obtaining a full rotary movement. This means, however, that the electric current to the motor must be fed in a special way. It might then be preferable to attach the mixer rigidly to the guide and let the latter be rotary. In order to secure a suitable turning speed for the mixer, a dampening means is arranged which prevents the mixer from jittering without control. This can be obtained by help of hydraulic dampeners having link arms.

Claims: A submersible mixer for liquids having an automatically changing of its direction, comprising a mainly vertically oriented guide (4) the lower end of which being attached to the bottom of a tank containing the liquid and a mixer (1) slidably arranged on said guide, the mixer (1) during operation automatically changing its direction horizontally and/or vertically influenced by the reaction force (F) from its own jet, without any adding of external energy, the horizontal movement of the mixer being limited by stopping means (7, 8), characterized in that the mixer (1) is provided with at least one rudder (12) arranged in the current created by the propeller (2), said rudder (12) or rudders being turnable around an axis or axes, in parallel with the guide (4) around which the mixer (1) may turn and being arranged to automatically turn between two inclined positions with relation to the direction of the flow from the mixer, the turning being controlled by stopping means (7) and (8). A submersible mixer according to claim 1, characterized in that the mixer (1) is provided with two rudders (12) in parallel being alternatively present in the current from the propeller (2). A submersible mixer according to claim 1, characterized in that the rudder, or rudders (12), are provided with spring means (13) which act upon the rudder or rudders to take two alternative inclined positions with relation to the current from the propeller (2). A submersible mixer according to claim 1, characterized in that a dampening means is arranged which limits the speed of the turning movement and/or frequency.

Inventors: FRIES, HJALMAR, KUME, KOIJE
Applicants: ITT FLYGT AKTIEBOLAG
Application year: 1988
Main classification: B01F11
IPC codes: B01F7, B01F15