US2238661A - Photographic utensil - Google Patents

Description

April 15, 1941. .1. w. SHAEFFER PHOTOGBAPHIC UTENSIL Filed July 6, 19

59 2 Sheets-Sheet l R 3 n a W w Patented A t. 15, 1941 UNITED STATES PATENT I OFFICE PHOTOGRAPHIC UTENSIL John W. Shaeffer, New York, N. Y.

Application July 6, 1939, Serial No. 283,117

4 Claims.

This invention relates to photographic trays employed in the processing of photographic materials such as papers, cut-film and plates to contain the solutions used for developing, fixing, intensifying, or otherwise treating the image. A portable shallow open form of tray has been generally adopted for such purposes so that the materials being treated may be easily accessible and available for immediate and continuous visual inspection.

The main object of the present invention is to control the temperature of the photographic liquids or solutions, and to this end provides an improved photographic utensil in the form of a tray construction incorporating heat transfer means as a permanent part thereof, and which functions in a simple and effective manner to bring the photographic fluid to, and maintain it at, the proper working temperature.

Manufacturers of photographic material are known to recommend preferable working temperatures at which the results of the processing will be best and most dependable. It is also well known that certain photographic solutions are sensitive to temperature and may become useless, as by precipitation, if the temperature is allowed to become too high or too low. It is also true that the speeds of the chemical reactions involved are dependent upon the temperature of the solution. Because of the fact that the amount of treatment given the photographic material, particularly in development, is of primary importance, in order to determine the length of time for the requisite reaction to occur, the temperature must be known, and in practice for accurate results it must be constant. In factorial development and also in the oil process of producing photographic prints the success of the procedure is especially dependent upon precise temperature maintenance.

In the past the most general method of maintaining a constant temperature has been to place a photographic tray containing the solution within another and larger open tray containing a bath of water and then to try to control the temperature of the solution by warming or cooling the water bath as may be necessary. Often electric heaters are placed in the bath to raise the tem perature. or ice may be used in case it is desired to cool the same. This method is a crude and unsatisfactory makeshift at best, which is particularly objectionable to use under the low intensity illumination of the dark-room. An objectionable amount of space is taken up by the water bath. During photographic processing the tray is manipulated to obtain even treatment by agitating the solution, particularly in development. In the course thereof the bath water often slops over into the solution, to its detriment. When a tray containing the solution and print is lifted out of the bath for examination or to bring it temporarily nearer the source of illumination for inspection, the bath water from the lower surface of the tray drips objectionably until the tray 'is returned to the bath.

In overcoming the dimcultles involved in prior methods of maintaining the temperature of solutions inphotograph-ic trays I have developed an easily manufactured photographic tray unit perfectly adapted to dark-room use having a hollow, or double wall construction providing a chamber through which a heat transfer fluid is circulated.

The tray unit is very compact, and may take.

the same shallow interior shape'and have the same capacity as prior photographic trays. A shell or jacket is incorporated as a unit with the tray, and may extend throughout the bottom and /or side wall areas, or selected portions thereof, according to the working conditions to be maintained. The chamber formed is made fluid pressure tight so that a heat transfer fluid may be circulated therethrough at any desired speed under forced flow and without danger of contamination of the photographic solution. Since a continuous constrained flow of heat transfer fluidis to be employed, the chamber may be of relatively small cubic content, and accordingly the new unit is not substantially larger, or less portable, than a simple tray as heretofore employed.

The cubic content of the fluid tight chamber may be less than the capacity of the tray itself as there will be a continuous inflow of fresh heat transfer fluid to the chamber and constant discharge therefrom. By making the chamber of relatively narrow cross section, but with a large heat transfer wall surface, hot or cold heat transfer fluid will flow through the chamber in the form of a confined shallow stream which results in a complete rapid change in the contents of the chamber. Whereas a bath of more or less quiescent liquid must be'of substantial volume,

' and is objectionable because of its bulk and likelihood of changing temperature under outside influences, the present arrangement is compact and because of constant change in the'fiuid is free from outside influences, and always has the proper heat transfer capacity to maintain the photographic solution at the correct temperature.

pressure-tight joint may be formed by any by a hose connection with the conventional hot i and cold water faucet, and a similar hose connectlon may be employed to conduct the discharge from the tray jacket to a'slnk or basin provided with a sewer outlet. Any desired lengths of rubber hose may be economically providedso that the tray construction may be used at any desired location. Also, any number of the improved photographic tray units may be connected together and supplied with a common heat transfer fluid where it is desired to maintain all of them at exactly the same working temperature,

The invention may be understood by reference to the following detailed description and various embodiments illustrated in the accompanying drawings. In such. drawings:

Fig. l is a longitudinal cross section of one embodiment of my invention taken on the line i-i of Fig. 2;

Fig. 2 is a top plan view of the same embodiment of my invention;

Fig. 3 is a fragmentary showing of the cross section of my invention taken on the line 3-3 of I .Fis.

Fig. 4 is a perspective view showing my jacketed tray connected ror'use;

Fig. 5 is a longitudinal cross section of another embodiment o'f my invention; and

Fig, (i is a cross section of my invention; taken on the line in Fig. 5.

In Figure l, the utensil includes a shallow open topped photographic tray portion i of rectanguiorm adapted to contain a processing solution, and comprising a bottom 2 and relatively low, preferably sloping, sidev walls 3. In this form a jacketing or shell member l forms an outer wall portion which encloses the bottom 2 and at least the lower portion of the side walls 3 as shown in Figures 1 and 3. The member G is either made integral with the side walls at their outer surface, or joined thereto, permanently or ,detachably, with a fluid tight seal, to form a fluid pressure tight chamber 5. Inlet and discharge connections such as hose receiving nipples dare provided in the jacketing shell, preferably at opposite ends thereof, for the introduction and re-' val of temperature conditioning fluids.

.iithough chamber 5 may be of any desired shape, it is preferably of small cross section relative to the tray itself so as to maintain the bulk of the unit at a minimum and facilitate handling. The chamber cross section need not be greater than 38% of the overall height of the utensil. The overall capacity is small being less than the capacity of the tray portion i, and heat transfer .iluid will circulate rapidly therethrough as a shallow stream and be constantly renewed even under a very low pressure head on the incoming supply. Inasmuch as the shape of the chamber does not give rise to obstructed pockets where flow is retarded, it is preferably constructed without directing fins. Nor is it necessary, in view of the limited size of these units, to provide sup porting elements between the hollow wall structure forming the chamber. As shown in the drawings, member 4 is formed with a flat bottom. l2 and provides a. hollow base for the utensil. The chamber for the heat transfer fluid is formed by the hollow base and hollow side wall structure in the form oi unit of Figures 1 and 3.

The tray and shell member may be formed of various materials such as enameled or corrosionresistant metal, or Bakelite, hard rubber, or other plastic. If the same are constructed of metal a known means, as for instance by a weld l Plastic members may be preferably joined detachably, or by cement, or integrally bonded under heat and pressure. The wall portions of the tray encased by the shell member will be made rela-- tively thin, consistent with the strength of material employed, to promote heat transfer between the transfer liquid and the photographic liquid in the tray.

In the embodiment shown in Figures 5 and 6 the photographic tray portion i is provided with a shell member ti on its lower surface only, so that a'fiuid tight chamber 9 is confined to the base of the unit beneath the bottom 2 of the tray portion. As in the embodiment shown in Figures 1 to 3, nipples b are provided in the jacketing member, which latter may be joined to the tray by a weld l or otherwise. Whereas the hollow cooled area of tray 0 isof limited extent, the heat transfer capacity of this embodiment is generally adequate for normal conditions and use, as it is common to employ an amount of processing solution which occupies only a fraction of the capacity of the tray, and the lesser capacity of the chamber may be compensated by increasing the rate of flow of the transfer fluid therethrough.

elU

This form of my invention is advantageously employed when the tray, or at least the bottom wall thereof, is constructed of corrosion-resistant metal, this having a much higher heat conductivity than a plastic tray.

In the operation of my device a flexible rubber intake hose id is connected between one of the nipples d and a source of temperature conditioning fluid, as shown in Figure 4. If the tray is to be heated such fluid may be hot water or steam under high or low pressure. In case it is desired to cool the tray cold water may be employed. Frequently cold tap water may be used with convenience. Where, as commonly the case, a dou ble hot and cold water faucet is available, the water may be easily adjusted to the exact working temperature desired for the tray liquid. A flexible discharge hose it may be connected to the other nipple to conduct the used fluid to the sink as shown, or if desired it may be circulated back by suitable means to the source of the conditioning fluid. Where, as shown, the capacity of the jacket is relatively small it will be evident that the fluid can be circulated therethrough as rapidly as desired and the rate offlow quickly varied by adjustment of the supply.

In certain photographic processing involving a number of steps such. as developing, acid shortstopping, and fixing, it is believed to be best practice to maintain all the solutions in a series of parallel, and as a result equal temperatures are maintained in all. These connections in no way limit the easy individual manipulation of each tray during the processing. In cases where the temperature of a tray is being maintained by water of a suitable temperature, the outflow from the fluid tight chamber can advantageously be employed in washing the previous processed materials, in which case the hose from the tray unit, or the last tray unit of a group, may be led directly into the washing chamber.

It will be evident that my inventionis capable of considerable modification and equivalency, and the scope of the invention is therefore not to be limited further than may be required by the appended claims.

I claim:

l. A portable photographic tray adapted to contain a processing solution for photographic sheets, said tray being of relatively small capacity so that it may be lifted during use, when desired, and tilted back and forth to agitate the processing solution over the face of a photographic sheet disposed therein, said tray being formed with heat conductive walls, a jacket secured to the tray and forming with at least the main wall area thereof a chamber for a heat exchange fluid adapted to maintain the processing solution in the tray at a selected temperature, a hose coupling fluid inlet port element in the jacket 3 adapted to be connected with a flexible heat exchange fluid supply hose for admitting fluid to the chamber and a fluid outlet port element in the jacket for discharging heat exchange fluid from said chamber, the chamber being shallow and of small capacity so that manipulation of the tray by hand is not prevented by the added weight of heat exchange fluid in the chamber, the chamber being fluid tight, thereby to prevent splashing of heat exchange fluid into the processing solution in the tray and enabling heat exchange fluid to be flowed through the chamber and replenished during use of the tray at any rate and pressure necessary to maintain the processing solution at a selected temperature. 4 2. A portable photographic tray adapted to contain a processing solution for photographic- 11.;

sheets, said tray being of relatively small capacity so that it may be lifted during use, when desired, and tilted back and forth to agitate the processing solution over the face of a photographic sheet disposed therein, said tray being formed with heat conductive side and bottom walls, said walls being hollow and housing a fluid tight chamber in heat conducting relation with the contents of the tray and adapted to have passed therethrough a confined flowing stream of fluid to temperature condition the tray contents by heat exchange through the walls of the tray, 9. fluid inlet port element in one of- 6 said side walls adapted to be connected with a flexible heat exchange fluid supply conduit for admitting fluid to the chamber and a fluid outlet port element in the jacket for discharging heat exchange fluid from said chamber, the chamber being shallow and of small capacity so that manipulation of the tray by hand is not prevented by the added weight of heat exchange fluid in the chamber, the chamber being fluid tight, thereby to prevent splashing of heat exchange fluid into the processing solution in the tray and enabling heat exchange fluid to be flowed through the chamber and replenished during use of the tray at any rate and pressure necessary to maintain the processing solution at a selected temperature.

3. A portable photographic tray adapted to contain a processing solution for photographic sheets, said tray being of relatively small capacityso that it may be lifted during use, when desired, and tilted back and forth to agitate the processing solution over the face of a photographic sheet disposed therein, said tray being formed with heat conductive walls, a jacket integrally bonded along its periphery to the trayand forming with at least the main wall area thereof a chamber for a heat exchange fluid adapted to maintain the processing solution in the tray at a selected temperature, a fluid inlet port element in the jacket adapted to be connected with a flexible heat exchange fluid supply conduit for admitting fluid to the chamber and a fluid out- 1 let port element in the jacket for discharging heat exchange fluid from said chamber, the chamber being shallow and of small capacity so that manipulation of the tray by hand is not prevented by the added weight of heat exchange fluid in the chamber, the chamber being fluid tight, thereby to prevent splashing of heat exchange fluid into the processing solution in the tray and enabling heat exchange fluid to beflowed through the chamber and replenished during use of the tray at any rate and pressure necessary to maintain the processing solution at a selected temperature.

4. A portable temperature conditioned photographic processing device comprising a tray -adapted to contain a processing solution for photographic sheets, said tray being of relatively small capacity so that it may be moved by hand during use, when desired, said tray being formed "with heat conductive walls, a jacket secured to the tray and forming with at least the main wall area thereof a chamber for a heat exchange fluid 5 adapted to maintain the processing solution in the tray at a selected temperature, a fluid inlet port element in the jacket, a heat exchange fluid supply conduit secured to said inlet port element and having inlet means at its other end for detachably connecting the conduit to a fluid outlet tap, such as a water faucet, supplying a suitable heat exchange fluid, said conduit comprising a light flexible hose for supplying a stream of fluid to the chamber while permitting free manipulation of the tray during temperature conditioning of the photographic solution, and a fluid outletport element in the jacket for discharging heat exchange fluid from said chamber, the chamber being shallow and of small capacity so that manipulation of the tray by hand is not prevented by the added weight of heat exchange fluid in the chamber, the chamber being fluid tight,- thereby to prevent splashing of heat exchange fluid into the processing solution in the 5 tray and enabling heat exchange fluid to be flowed through the chamber and replenished during use of the tray at any rate and pressure necessary to maintain the processing solution at a selected temperature.

JOHN w. SHAEFFER.

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