US 3116913 A
Description (OCR text may contain errors)
Jan. 7, 1964 K. LANE LIQUID AGITATING APPARATUS Filed May 29, 1961 M E @a maf/.oww
United States Patent 3,116,913 LEQUID AGITATING AP?ARATUS Kingdon Lane, 12d@ Madison Ave., New York 28, NX. Filed May 29, 1961, Ser. No. l13,l66 4- Claiins. (Cl. 259-405,)
This invention relates to apparatus for stirring or agitating liquid contained in a tank or other vessel provided therefor.
Although the present invention is of general utility, being adaptable to the agitation of all types of liquids, it will hereinafter be described with specific reference to the art of photography and in particular to the field of developing photographic film.
One of the current methods of developing photographic film entails unwinding the film from its camera take-up spool and feeding it into the spiral tracks of a specially constructed reel so that the convolutions of the film are separated from one another. The reel is then placed into a light-tight stainless steel tank, after which the developer solution is poured in. The tank must now be rocked or oscillated back and forth for the desired period of time, say 45 minutes or so. After the developer is removed, the smic procedure must be followed with the hypo or fixing solution and then with the washing liquid for removing remaining traces of hypo from the film. Merely by way of example, one type of equipment usable in the aforesaid manner is that sold under the trademark Nikor by the Nikor Products Company and disclosed in U.S. Patents Nos. 2,073,978 and 2,218,727.
Mechanical devices for effecting the required rocking of the tank and its contents are avail-able on the market. They are, however, fairly complex in construction and thus quite expensive. For the ordinary photographer desirous of doing his own film developing, therefore, an agitating device of this kind is usually beyond his means and he must resort to manually rocking, tilting and turning the tank, a procedure which is both tedious and tiring and also restricts him from performing other tasks at the same time.
In addition, it has been found that these agitating procedures, whether mechanically or manually executed, frequently lead to unevenly developed film, either by virtue of some portions of the film being overor underdeveloped or by virtue of some portions of the developer being fixed or washed oft more than others. The underlying causes of these defects appear to be the type of motions imparted to the tank during the film treating periods, which results in an uneven contact of the respective types of liquids, i.e. developer, hypo and hypo-eliminator, with the exposed film.
It is, therefore, an important object of the present invention to provide novel means for agitating the developer or other film-treating liquid in a developing tank so as to ensure that all parts of the exposed roll of film are equally and uniformly contacted by the liquid.
It is another object of the present invention to provide a lilm treating apparatus which is automatic in operation and requires no manipulation or human supervision except for the starting and stopping of the apparatus.
lt is also an object of the present invention to provide apparatus of the aforesaid type which is inexpensive to manufacture and thus may be made readily available even to the average photographer at extremely low cost.
A more specific object of the present invention is the provision, for use with such apparatus, of a stirrer unit which is equipped with a magnetized, rotatable stirrer element of novel construction and is adapted to be inserted into a tank beneath the film-holding reel thereof for actuation by a magnetic motive element positioned outside the tank.
A related object of the present invention is the provision ICC of such a stirrer unit in which the stirrer element may be shaped in the form of a bar, cross or like multi-armed body and carries a plurality of bar magnets at spaced ones of its extremities.
Generally speaking, in accordance with a preferred aspect of the present invention the stirrer unit is composed of a pair of spaced, parallel, stainless steel plates rigidly secured to one another. The bottom plate may be imperforate, but the top plate is provided with a plurality of relatively large apertures or holes spaced around its center. Thestirrer element, which may be made of any suitable chemically resistant material such as Bakelite, Teonj polystyrene or other synthetic resin, is disposed between these plates and is supported thereby for rotation about an axis perpendicular to the planes of the said plates. Preferably, the stirrer element is crossshaped or four-armed, with each opposite pair of arms having slanted top faces extending over about one half of their lengths and directed oppositely to one another transversely of the respective arms. The arrangement is such that two of the arms have the slanted top faces at their outermost end regions, While the other two arms, which carry a pair of bar magnets embedded in their outermost ends, have the said slanted top faces at their innermost end regions, whereby the stirrer element is adapted to act on a liquid in the manner of a screw or propeller. rThe magnets are disposed parallel to one another tangentially of the circular paths of movement thereof, and the respective north poles may face in opposite directions.
Alternatively, the stirrer element may be bar-shaped, in which case its two arms may, although they need not, be provided with oppositely slanted top faces, these being disposed, if present, adjacent the middle of the bar.
If desired, the stirrer element, regardless of its shape, may be provided in its respective arms with vertical holes to enhance the agitating action, these holes being spaced from one another longitudinally of the arms between the center and the outermost extremities of the stirrer element.
When a stirrer unit of the types provided by this invention is placed into a developing tank, the latter may be positioned above a motive element, say a bar, adapted to be rotated by a motor about an axis aligned with the stirrer elements axis of rotation and carrying two bar magnets at its opposite ends. Rotation of this bar thus will cause the stirrer element to be rotated due to the interaction between the last-named magnets and those carried by the stirrer element.
The foregoing and other objects and characteristics of the present invention, as well as the advantages thereof, will be more fully comprehended from the following detailed description of preferred modes of carrying out the invention, when read in conjunction with the accompanying drawing in which:
FIG. l is an elevational view of a film developing apparatus embodying the principles of the present invention, parts of the apparatus being broken away to show interior details; p
FIG. 2 is a fragmentary sectional view, on an enlarged scale, of a part of the apparatus shown in FIG. l and illustrates details of the magnetic stirrer unit of the present invention at the bottom of the developing tank;
FlG. 3 is a sectional view taken along the line 3-3 in FIG. 1;
FIG. 4 is a sectional View taken along the line 4 4 in FIG. l;
FIG. 5 4is a sectional view taken along the line 5-5 in FIG. 4;
FlG. 6 is a sectional view taken along the line 6-6 in IG. l;
FiG. 7 is a plan view, partly broken away, of a modiprinciples of the present invention are embodied in means adapted for use with a photographic film developing tank 1t) of the commercially available type known as a Nikor tank Iwhich is provided at its top with a cap l1 to cover the liquid inlet structure (not shown). The tan-k is made of stainlessrsteel so as to beresistant to corrosion and attack by the chemicals incorporated in the various lmtreating solutions. The inner diameter of the tank fltl is large enough to accommodate a hlm-holding reel `l2 which is of conventional construction and thus will not be explicitly described herein.
In accordance with the present invention, the means 13, i.e. the stirrer' unit, for agitating the lilm-treating solution in the tank is positioned directly in the latter at the bottom thereof so as to provide the support for the reel l2 when the same is inserted into the tank. Refer` ring now in addition to FlGS. 2 to 5, it will be seen that the stirrer unit `ll3 comprises a pair of flat stainless steel plates 14 yand l5 of circular outline conforming to the outline of the tank lil. The plates ld and l5 are rigidly secured to one another by means of four studs y16 the opposite reduced-diameter ends'of which extend through corresponding holes in the respective plates and are peened or flattened down over the outer faces of the plates 14 and l5, `as shown at loa and lob in FIGS. 2 and 3. The upper plate ld is provided with four apertures or openings 17 which are preferably stamped out of the plate, leaning a central hub l and four radial arms 19 interconnesting the said hub wi-th the outer peripheral portion of the plate lll. The latter is further provided :in its peripheral portion with a circumferential groove Ztl, and in the anms 19 with radial grooves 2l, these grooves being formed in any desired manner and serving to rigidify and stengthen the plate lll. Similarly, the bottom plate 15 of the stirrer unit is provided with a circumferrnential stiffening groove Z2 and radial stifening grooves 23. Both theitop and bottom plates are centrally indented, as shown at'Z. and 25, and the indents are provided with axially aligned holes.
Although it is preferred that the stirrer unit frame A-lS-lo so lfar described be constructed in the imanner disclosed, it is contemplated within the purview of the present invention that the plates may be made of other materials than stainless steel, for example synthetic resinous materials, as lon-g as the frame has the requisite strength and sturdiness to withstand the rigors of longcontinued use. Moreover, the stirrer unit frame may be shaped otherwise than as shown, as long as it provides a space and bearings for the stirrer element (still to be described) and provides for free access of the liquid into the said space from the top and the sides thereof. in this connection it is to be note-d that there need not be precisely four holes in the top plate. t is actually preferred that these holes be as large as possible, but in conjunction with this point it must be remembered that the strength of the top plate cannot be reduced too much, and it has been found that the four holes 17 and the intervening arms 19 provide the optimum access for Vthe liquid and strength of the top plate 14.
The stirrer element 26 according to one embodiment of the present invention is a body made of a suitable synthetic resin, eg. Bakelite,k Teflon `or the like, and shaped in the form of a cross with four arms 2'7, 23, 29 and 3). Press-fitted into a bore 26a (FIG. 5) in, and projecting beyond the opposite faces o-f, the center of the body 26 is a pin 3l provided at its opposite ends with a pair of reduced-diameter extensions Sla and Slb freely .rotatably received in the holes provided in the indents Zd and 23, respectively, of the top and bottom plates .le and "magnets 39 and that its opposite ends.
i l5 of the stirrer unit i3. The stirrer element Z6 is thus rotatably arranged between the plates lll and l5.
As clearly shown in the drawing, the iarms Z7 and 29 of the stirrer element carry adjacent their free ends or extremities a pair of bar magnets 32 and 33t. These magnets are embedded in the synthetic res-in or other plastic material of which the element 2o is made, so as to be protected against attack by the chemical film-treating solutions to be agitated, and are preferably disposed with their respective north poles (and thus also their south poles facing in opposite directions and with their longitudinal axes oriented tangentially to the path of rotation of the stirrer element arms. The magnets 32 and 33 constitute the means which are adapted to be acted upon by the means (still to be described) for setting the stirrer element 26 into motion.
The arms 27 to 3d of the stirrer element are also provided, respectively, with slanted top faces 3d, 35, 3f and 37 exten-ding over one 'half of the length of each arm. On the arms Z8 and 3@ these slanted faces are located at the outer halves of the arms, but on the arms 27 and 2h, due to the presence of the magnets 32 and 33, the slanted faces are located at the inner halves of the respective arms. All of the said slanted top faces are oriented to descend in the direction of rotation of the stirrer element 26, as indicated by the curved arrow in FlG. 4. Referring in particular to FiG. 5, furthermore, it will be seen that the lowerrnost and leading edges of the slanted faces 34 to 37 of the stirrer element arms 27 to 39 do not start at the bottom surfaces of the said arms but a short distance up therefrom. Thus, the arms have at their leading sides coextensive with the corresponding slanted faces narrow vertical edges 34a, 35a, 36a and 37a which function to enhance the turbulence of the liquid through which the stirrer element moves, as Will be more fully explained presently. It desired, the stirrer unit 13 may be vprovided with a bail or handle 13a affixed in any suitable manner to the central hub 1S of the top plate 14 so as to facilitate the process of placing the unit into or removing it from the tank itl.
The mechanism for actuating the stirrer element is best shown in FIGS. l and 6 and comprises a motive element 33 in the form of a horizontal bar carying a pair of bar The bar 38 is secured in any suitable manner to the vertical output shaft 4l of an electric motor 42 which is stationarily mounted in a housing 43 having a top cover plate 44. Like the magnets 32 and 33 in the stirrer element arms 27 and 29, the magnets 39 and d@ are oriented tangentially to the path of motion of the ends of the bar 38. The motor 42 is connected by suitable wiring 45 to an on-olf switch 46 and to an electric cord 47 extending out of the housing 43 and carrying a standard plug (not shown) adapted to be inserted into any standard house socket. The switch is lprovided with an actuating arm 46a disposed exteriorly of the housing 43.
In operation, when the tank l@ containing the stirrer unit 13 and the lm-holding reel l2 has been lilled with the desired film-treating liquid, it is placed onto the top plate 44 of the housing 43. The cord 47 being plugged in, the switch arm 46a is moved to the on position, whereby the motor d2 rotates the bar 38. When the magnets 39 and 4t) of the motive element 38 come into vertilcal alignment with the magnets 32 and 33 of the stirrer element 26 for the first time, the magnetic attraction therebetween causes the stirrer element to be set into rotation. To this end, of course, care must be taken that the plate 44 is not made of a material which might act as a magnetic shield. The rotating stirrer element, acting in the manner of a ships screw or propeller, causes a great 'deal of turbulence in the liquid in the tank. This will be readily understood when it is considered that the slanted top faces of the arms 27 to 30 basically tend to produce a vertical displacement of the liquid in contact therewith, while the corresponding vertical edges 34a to 37a tend to produce a horizontal displacement of the liquid in contact therewith. This last action is also achieved, to a much greater extent, of course, by the full-height portions of the vertical leading sides of the arms 27 to 30 adjacent the respective slanted portions thereof.
As a result, the liquid is agitated throughout the tank and brought into contact with all parts of the exposed film being developed. The possibility of uneven developing, fixing or washing is, therefore, substantially eliminated. At the same time, once the motor has been turned on, the film-treating procedure will be carried out automatically which, especially in the case of the initial application of the developer, relieves the person doing the developing of the necessity for continuously manipulating and manually rocking the tank for an extended period of time.
It is contemplated by the present invention that stirrer elements having shapes other than the four-armed cross 26 may be employed to advantage, the only fixed requirement being that any such element must carry at least one magnet, and preferably a pair of magnets, located in a manner corresponding to the location of the magnet or magnets of the associated motive element. One modified type of stirrer element is illustrated in FIGS. 7 fand 8. The element 26 there shown is an elongated bar 48 carrying magnets 49 and Si? at its opposite ends, the longitudinal axes of the magnets being disposed in the plane of rotation of the bar 4S and at right angles to the axis of rotation of the latter as defined by the pin 51. The bar 4S is further shown as being provided, in lieu of slanted top faces, with a plurality of vertical holes 52 disposed between each of the magnets 49 and Si) and the central axle pin S1. Such holes are found to enhance the normal agitating action of the bar when the stirrer unit which includes the said bar is located in a developing tank and to aid in ensuring that any chemicals in the film-treating liquid then in the tank are prevented from settling out of the liquid to the bottom of the tank.
lt is to be understood, of course, that the bar 48 may additionally be provided with oppositely directed slanted top faces like the stirrer element 26, or that, if desired, the holes S2 may be eliminated and only such slanted faces employed. By the same token, the element 26 may be provided with holes like those in the bar 4S.
With respect to a stirrer element such as the multiarmed element 26, furthermore, it will be understood that not all of the arms thereof need be provided with slanted top faces and that some of the slanted top faces may be formed so as to descend oppositely to the direction of rotation of the stirrer element.
While there have been described herein preferred embodiments of the present invention, it will be clear that many changes and variations may be made in the structural features and relationships disclosed, as well as in the means and manner of constructing the stirrer elements, units and associated apparatus, without in any way departing from the spirit and scope of the invention as defined by the appended claims.
Having thus particularly described my invention, what I claim and desire to secure by Letters Patent is:
1. A magnetic stirrer unit adapted to be placed into a liquid-containing vessel at the bottom thereof, comprising top and bottom plate members rigidly secured to one another in spaced relationship and peripherally thereof, said top plate member being provided with a plurality of openings spaced about its center, and a multi-armed stirrer element supported by said plate members in the space therebetween for rotation about an axis extending from one of said members to the other, said stirrer element carrying on at least some of said arms thereof adjacent the outer extremities of the latter respective magnets adapted to be set into motion about said axis by correspondingly movable magnetic forces acting from exteriorly of the vessel, and each of said arms being provided with a slanted top face descending from the top of the arm in the direction of rotation of said stirrer element and terminating at a vertical front edge of the same arm extending up from the bottom thereof, whereby both vertical and horizontal displacements of liquid may be achieved.
2. A stirrer unit according to claim 4, said plate memers being disposed parallel to one another and providing vertically aligned bearing locations for said stirrer element, and said stirrer element comprising a four-armed, crossshaped body the axle of which is disposed substantially at the hub of said body, vo opposite ones of said arms of said stirrer element carrying in the region of their outer extremities a pair of bar magnets, respectively, the longitudinal axes of which extend substantially tangentially to the paths of movement of said extremities of said arms, each of said slanted top faces extending over substantially one half of the length of the respective arm, said slanted top faces of the two magnet-carrying arms being located at the inner halves of the latter adjacent said hub, and said slanted top faces of the remaining two arms being located at the outer halves of the same.
3. A stirrer unit Iaccording to claim 1, said plate members being disposed paraliel to one another and providing vertically aligned bearing locations for said stirrer element, and said stirrer element comprising a two-armed, barshaped body the axle of which is disposed substantially at the center of said body, said arms of said stirrer element carrying in the region of their outer extremities a pair of bar magnets, respectively, the longitudinal axes of which extend substantially tangentially to the paths of movement of said extremities of said arms, each of said slanted top faces extending over substantially one half of the length of the respective arm at the inner half of the same adjacent said axle.
4. A stirrer element for use in agitating liquids, comprising a substantially plane body adapted to be mounted for rotation about an axis substantially perpendicular to the plane of said body and having four arms extending at right angles to one another from said axis of rotation, each of two opposite ones of said arms carrying a respective bar magnet, said bar magnets being arranged parallel to one another and having their respective sets of poles reversed with respect to one another, and each of said arms being provided with a slanted top face descending from the top of the arm in the direction of rotation of said body and terminating at a vertical front edge of the same arm extending up from the bottom thereof, each of said slanted top faces extending over substantially one half of the length of the respective arm, said slanted top faces of the two magnet-carrying arms being located at the inner halves of the latter adjacent said axis, and said slanted top faces of the remaining two arms being located at the outer halves of the same, whereby both vertical and horizontal displacements of liquid may be achieved.
References Cited in the file of this patent UNITED STATES PATENTS '1,826,200 Byers et al. Oct. 6, 1931 2,128,921 Draeger Sept. 6, 1938 2,506,886 Okulitch et al. May 9, 1950 2,549,121 Osterheld Apr. 17, 1951 2,912,343- Collins et al Nov. 10, 1959 2,984,462 OConnor May 16, 1961 FOREIGN PATENTS 1,026,902 France Feb. 11, 1953