US 2350534 A
Description (OCR text may contain errors)
2 SheerLs-Sheet l A. ROSINGER MAGNETIC STIRRER Filed Oct. 5, 1942 Q v fiw q /0 2 8 mm IIu/I 5 2 a H a w O U mmiflmm nu 1 O W x June 6, 1944.
June 1944- A. ROSINGER MAGNETIC STIRRER Filed Oct. 5, 1942 2 Sheets-Sheet 2 J fig vi FIG.
INVENTOR. v ARTHUR ROSINGER Patented June 6, 1944 I UNITED STATES PATENT OFFICE I maon zzz gl iaana Applicat i ofiz cz lrr 460,841 6 Claims. ('01. ass-10s) This invention relates to a stirring and mixing device, and has for its main object to provide a device of this character, which will operate by.
magnetic action, in a novel and efflcient manner.
Another object of my invention is to provide a device of the type mentioned, in which a stirrer proper will be represented by an element free of movement and preferably unconnected, but which will react to magnetic forces.
$till further objects of this invention will be apparent as the specification of the same proceeds, and, among others, I may mention: To provide a device, as--indicatcd hereinbefore. which will automatically align itself under the action of the magnetic-forces to an efflclent position of operation, which will be operated by a permanent magnet, which will use highly magnetic alloys for such permanent magnet, which will be adapted to be used'for various operations, besides stirring or mixing, like grinding, pulverizing, etc., and in which the free magnetic operating element proper will be encased in an inert shell, so that the magnetic element will have no action on the material operated on.
In the drawings, forming a part of this speci- Fig. 2 is a sectional view through the magnetic stirrer element proper, the section being taken on the line 2-2 of Fig. 1;
Fig. 3 is a plan view of the device illustrated in Fig. 1, portions of the same having been removed, and others being shown in section.
Referring now to the drawings more in detail, by characters of reference, the numeral l0 indicates a casing or box, in general, having a bottom Ii, side walls i2, and a removable top i3.
Secured in about the center of the box is an electric motor I, having a vertical shaft i5, rotated by the same. The motor may be secured in an operative position in said box or casing ill, by any appropriate means, as by having secured on the motor housing the bands i6 and ii, which may be continued in arms it and I9, reaching to the respective side walls i2, and being secured thereon, as at 20.
The electric motor may have the'usual wire connections 2i, leading to a regulating rheostat 22, and therethrough to a switch 23, and finally, in this embodiment of the invention, to a usual plug 24, whereby it may be connected into an electric feeding circuit.
A U shape or horseshoe permanent magnet,
generally indicated by the numeral 25, is secured on the shaftiS, as indicated at 26, so as to rotate therewith.
Overthe magnet 25, on the top or cover [3 of the casing I0, ,I place a container or vessel 21,
net 25 will have opposite magnetic polarity at their upper exposed terminations, as indicated by N and S, respectively, one termination being north andthe other south polarity.
The magnetic stirrer element 29 in this embodiment is in the form of a small circular rod, which will settle on the bottom 34 of the vessel 21 in the position indicated in the Fig. 1, as will be obvious.
It also will be obvious that the respective ends of the magnetic stirrer rod 30 will take up polarities which will be opposite to the strong N and S polarities of the magnet 25,a s also indicated in Fig. 1.
Now, when motor H, and the shaft is connected therewith, will be set into rotation, magnet 25 will rotate therewith and will cause the stirrer element 29 to follow the same, said stirrer element describing a rotary motion around its vertical center axis on the bottom 34 of the vessel 21 and thereby causing the liquid 28 to be strongly stirred and mixed.
The speed of rotation of the stirrer element proper 29 will depend on the speed of rotation of the magnet 25, and may be increased or decreased as necessary, by regulating the speed of the motor.
My experience has been that even without using extra strong magnets and very high motor speeds, the liquid 28 may be stirred or mixed by my method in an eflicient manner and in a very short time, indeed, the upper surface of the liquid will take up a very deep curved contour, forming a deep vortex, thereby, of course, insuring a thorough mixing and stirring.
To aid in the eflicient operation of the device, I use a comparatively heavy and strong permanent magnet 25, when desired made of any of the specific, strongly magnetic alloys, well known in this art, and, similarly, a comparatively strong permanent magnet 30 for the stirring element 29. I also make the neutral shell or cover 3| as thin as possible and also make the top i3 of the casing i0 very thin and arrange the operating top surfaces or terminations 35 and 36 of the magnet 25, as close to said top I: as possible, all these factors contributing to a strong action between the rotating magnet 25 and the stirrer 29.
The poles of the magnet 25 may be placed at .the two sides of the container 21 and rotate GU therearound instead of underneath it.
It is also possible to use a magnet with a single operating pole being moved in -a predeter mined path outside of but close to the wall of the container, thereby causing the magnetically responsive element within the container to follow 5 said predetermined path and perform the stirring and other operation on the medium in the container.
Obviously in a specific case, the magnet may be placed within the vessel and moved therein, and
similarly in a specific embodiment of my invention, the operating element may be secured to the wall of the vessel by a flexible cord, chain and the like,.still permitting considerable free movement along a desired path.
I also want to remark that the stirring element proper 30, and the like, obviously may be used without the inert or neutral shell or covering indicated at 3i. I use such inert covering or shell,
the experiment without doing or watching the stirring operation with the added advantage, that no rotating shaft is in the way of the'mixing operation.
My novel magnetic operating element may be shaped according to the duty to be performed by it, and, as has been indicated, it may be used not only for stirring or mixing, but also for grinding and other appropriate operations, and it may be made in larger or more powerful units for actual industrial work, and not only for laboratory purposes.
only where a magnetically responsive material of the operating element proper, like .iron, steel, etc., would have a harmful effect on the liquid 28, indicated in the drawings, or on any other material within the container, and in such a case said shell or covering willbe of an inert or neutral character to the material or medium in the container, so as to have no effect thereon. Such covering will be selected according to the purpose in view, and it may be made of porcelain, glass, Bakelite, an appropriate plastic, etc.
As has been indicated in the drawings, I prefer to use a permanent magnet for the source of the magnetic effect, but of course, an electric magnet also may be used, with appropriate construction for rotating or otherwise moving the same.
The movement of the magnet ma also be different from the described circular one, indeed, various types of relative movements may be designed between the vessel and the outer magnet,
moving either the vessel or the magnet, or both, for the purpose in view.
It also will be understood that the material of the vessel in which my magnetic stirrer, grinder and the like, is to operate, must be nonmagnetic, and, similarly, the casing ill, or other support for the container, and similar auxiliary structure, also must be of nonmagnetic material.
In the drawings I indicated a rotary drive for the magnet 25, but, of course, it may be moved in many other manners. as has been mentioned hereinbefore, and it may have other driving means than an electric .motor, it may even be moved manually, if desired.
The main novelty of my magnetic operating device is, that the operating element inside of a container or the like, is free to move and not connected to any other part or element, as a rule,
and will have no mechanical construction to sup- 6 port or guide it.
In this manner, a stirring or other operation may be performed in an entirely closed vessel, no part projecting into the vessel, the contents of the vessel may be easily placed under any pressure from high to'vacuum, no unnecessary vibrations, noise, electrical eiIects, etc., are produced which may harmfully influence the opera- Another important advantage of my novel device, when used for grinding, pulverizing and similar operations, lies in the fact that the mag netic pull will be added to the weight of the operating element and thereby the efliciency of the operations will be increased.
My element may also easily be made self aligning, automatically keeping its axis of rotation.
I may mention that one specific form of using my device for quick and unusually eflicient stirring and mixing a liquid in a chemical laborotory, which I tried, consists in placing the magnetic stirrer element proper 29, eccentrically on the bottom of the container, that is, to one side from the center, while the U-shaped magnet 25 remain centrally placed, as shown in Fig. 1. In this case the magnetic stirrer proper 29, not only will rotate around its own center, but will, at the same time, travel around on the bottom of the container, so that, to my observation, stirrer element 29 will describe a composite movement which I believe is epicyclic and the result in stirring eifect is, as mentioned, strikingly improved and quickened.
What I claim as new, is:
1. In a stirrer for chemical laboratories to be used for a liquid medium, a container of nonmagnetic material for said medium, an elongated free moving stirrer element of magnetic material adapted to be dropped to the bottom of the container, a rotary U-shaped magnet vertically placed underneath said bottom with its poles closely thereto, and means to rotate said magnet on its vertical center'axis,. whereby rotation of the U-shaped magnet will cause said magnet to describe a predetermined movement within said container.
2. In a stirrer, in the combination of claim 1, said magnetic stirrer element being shorter than any transverse dimension of said bottom,
3. In a stirrer, in the combination of claim 1, said magnetic stirrer element being shorter than the transverse dimensions of said bottom, said magnetic element being adapted to be placed eccentrically on one side of the bottom, whereby it will be caused to describe an epicyclic movement, travelling around and rotating on its axis, si-
4. In a stirrer, in the combination of claim 1,
a neutral coating on said magnetic stirrer element'to prevent an interaction between said element and the liquid medium to be stirred by the both, said magnetic element and said U-shaped,
magnet, being permanent magnets of high magnetic alloy.
combination of claim 1, I