DE2323725A1 - METHOD OF DRYING PHOTOGRAPHIC FILMS AND DRYING DEVICE FOR CARRYING OUT THE METHOD - Google Patents

Description

u.z .: K 305 + a (Vo / Fi / f) May 10, 1973

Caee FM / fg-17579-F 3M / 276

MINNESOTA MINING AND MANUFACTURING COMPANY Saint Paul, Minnesota, V.St.A.

¹¹ Process for drying photographic films and drying apparatus for carrying out the process "

Priority: May 10, 1972, Italy, No. 5O198-A / 72

The invention relates to a new method for drying photographic films soaked with water by evaporation of the water with heat energy supplied from at least one external heat source and removal of the resulting heat energy Water vapor with an air stream sweeping the film to be dried, as well as a drying device for carrying out the Process, especially when used in the field of radiography and the graphic arts industry.

It is known that photographic films are developed and fixed after exposure and finally washed or watered and then dried to remove the water soaked in the films at the end of this processing.

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Such photographic films soaked with water can be dried either by bringing them into drying rooms where hot dry air is blown, or by they are passed through a dryer consisting of a drying chamber provided with an inlet and an outlet and a drying chamber consists at least partially arranged in the drying chamber transport device. As a transport device are in general Rollers rotating about their axes are provided, through which the brought into contact therewith

Film along a film transport plane formed or defined by the contact points between the rollers and the film is moved. In particular, these rollers can be in the form of two rows associated with one another in pairs and with one another contacting rollers arranged v / earth.

Dryers of the second type are usually included Equipped with a fan that takes the air to a heater and then further along the two sides of the through the drying chamber running Filxns leads. The stream of hot air dries the film the faster the higher the temperature of the air blown against the film.

A conventional resistance heater or any other heat energy source, for example an infrared radiation source, can be used as the heater (British Patent No. 1,131,681) can be used.

A drying device of the type described above liat Cons because

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the photographic film is damaged if it is exposed to excessively high temperatures, for example above 60 to 70.degree. On the other hand, the dryer loses a large part

its effectiveness when an air stream with lower tempera damage
door is used to avoid a / of the film.

Known drying devices of this type also have the disadvantage that a certain warm-up time must be waited for must before the air is heated to operating temperature.

The invention is therefore based on the object of a new method to create that enables photographic films soaked with water to be produced quickly, cheaply, in a simple manner and ■ drying the passages in devices without the risk of damage caused by excessive heating have through which the film is passed through a drying chamber, and a device for performing this method to make available, which is characterized by small overall dimensions and without preheating to dry the Films can be used.

It has now been found that this object can be achieved, surprisingly, by the fact that the photographic to be dried Film is irradiated both with infrared rays, whereby the water to be removed from it is evaporated, as well as blown with non-heated air rays, through which the thereby formed

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Removes water vapor and at the same time prevents significant heating of the film to be dried. The intensity the infrared radiation and the speed of the air supply or the amount of air blown against the film per unit of time must be suitably coordinated with one another in such a way that there is a substantial rise in temperature in the film to be dried is avoided.

The invention thus relates to a method of the type indicated at the outset, which is characterized in that the to drying film is supplied with the heat of vaporization for the water to be removed essentially by irradiation with infrared rays and the film is wiped with an air stream whose temperature is at room temperature, the conditions under which the film to be dried is irradiated with infrared rays and blown with air, can be selected so that it is dried without a substantial increase in temperature.

In the method of the invention, the material to be dried becomes photographic As the film passes through the drying chamber, it is guided past sources of infrared radiation through which it can be seen from both sides is irradiated with infrared rays. In addition, in the drying chamber there are air sources (outlet openings) for non-heated Air is provided, which is supplied to the air sources by means of at least one fan and both sides of the to be dried Film flows towards it. The transport speed of the film to be dried, the length of the drying chamber, the power of the infrared radiation sources, the power consumption and the delivery rate of the fans that supply the air sources with non-

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supply heated air, the temperature of the air,

with which the film to be dried flows and the spatial arrangement of the air and infrared radiation sources is thereby chosen so that the film at the end of the drying section is essentially dry without appreciably, e.g. by more than 5 to 10 C, to have been heated.

According to an essential feature of the invention, the infrared radiation and air sources arranged in such a mutual position to one another that the against the to be dried Film blown not through the air from the infrared radiation sources outgoing infrared rays is heated and thus can cool the film to be dried.

According to a preferred embodiment of the invention
elongated infrared radiation sources used and arranged according to the above-mentioned features at a distance of 1 to 3 cm from the film transport plane.

According to the invention, the infrared rays and the unheated air are preferably admitted to the from independent, physically or spatially separate sources
the drying film so that the air is not directly heated by the infrared radiation source. In the context of the invention, “non-heated” air means air at room temperature, ie air whose temperature is in a range from 15 to 35, preferably 18 to 23 ° C.

According to a preferred embodiment of the invention
the infrared radiation sources between two air sources

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arranged. The infrared radiation sources are preferably only in each case during the passage of the film to be dried heated by the drying device of the invention, whereby

of course an energy saving can be achieved.

According to a preferred embodiment, the invention relates to further a method of drying a water-soaked photographic film, the film being passed through a drying chamber is performed, which is characterized in that one

a) on the film to be dried when passing through the drying

rl

device both infrared rays and non-heated Allows air currents to impinge,

b) Infrared radiation sources of elongated shape used, spaced on both sides of the film transport plane are arranged from 1 to 3 cm,

and

c) the temperature of the incident on the film to be dried Maintains air within a range of 15 to 35 ° C.

The invention further relates to a drying device for drying a photographic film soaked with water, having a drying chamber which has an outer inlet and an outlet, and a film transport device which is at least partially arranged in the drying chamber and which is characterized in that in the drying chamber on both sides of the film transport plane _; a) elongated infrared radiation sources facing the film transport plane at a distance of 1 to 3 cm and b) air radiation directed onto the film transport plane

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supply
swell to / from ^T iUft at a temperature of 15 to 35 ° C

are provided.

The invention further relates to methods and devices for drying photographic films of the type described above, wherein the air and the infrared rays pass through separate outlets to the film to be dried and / or the drying conditions are chosen so that the film is not more than 5 to 10 ⁰ C heated.

The drying devices of the invention can either be advantageous as parts in an automatic system for processing or developing photographic films for X-ray

the business

genography or / graphic / or used as a table dryer will-. Drying devices according to the invention which are used as table dryers are to be further described in

be equipped with a known type with a carrier plate and squeeze rollers. In both cases the Using a drying device according to the invention, the speed with which the film to be dried through the drying chamber running, the length of the drying chamber, the power consumption of the infrared sources and the power of the fan (s), that or that supplies or supplies the air sources, from the specialist on a case-by-case basis according to the respective To choose conditions of use.

Tabel
In the following / 3 are preferred values for the construction

operational and operating condition characteristics of three different

summed up / drying devices according to the invention / those for drying

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X-ray films of the type that can be developed or processed in an automatic system (e.g. the applicant's X-ray film * of type R) _{} can} be used.

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Tabel

speed 0.9 5 1
- 1.1 cm / sec. 1.4 - 1 2
, 6 cm / sec. 2-22 4th 3
cm / sec. Length of the drying chamber 500 - 8 cm 10 - 15 cm 15th 600 - - 20 cm Infrared lamp power - 1000 W 1000 - 1500 W 1200 (each) - 1800 W Number of lamps 300 2 2 - 4th - 6 Delivery rate of the blower (each) - 600 m ³ / h 500 - 700 m ³ / h 900 m ³ / h Fan power 50 - 60 W. (each) 60 - 80 W 70-100 W.

Quartz-tungsten lamps are preferred as the infrared radiation sources those with a high operating temperature are provided, the color of which corresponds to that used in photo reproduction systems can be used, e.g. the types Toshiba QIR, 13381 X from Philips or Infra-Red from General Electric.

If you compare the fourth given in the table above with those of known devices, the effectiveness of the Method and drying device of the invention without further details evident. A drying device of the type XD-304 from the applicant has, for example, the following characteristics: "

Speed 0.8 - 1.1 cm / sec.

Length of the drying chamber 36 cm

Resistance power consumption ...... 3 KW

3 Fan delivery rate 980 m / h

Fan power consumption 175 W

Below is a preferred embodiment of the invention Drying device stating some alternatives with regard to the actual drying area based on the drawing explained. In the drawing shows:

Figure 1 is a sectional view of a preferred embodiment

a table drying device according to the invention; FIG. 2 is an enlarged, schematic cross-sectional view the drying area of the drying device from

Figure Ij
FIG. 3 is an enlarged schematic cross-sectional view of a

second embodiment of the drying area j

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FIG. 4 is an enlarged schematic cross-sectional view

a third embodiment of the drying area; FIG. 5 is an enlarged schematic cross-sectional view a fourth embodiment of the drying area

and
FIG. 6 shows an enlarged schematic cross-sectional view of a fifth embodiment of the drying area.

The drying device shown in Figure 1 has fans A and A ^ ₁ , ventilation chambers B and B., air sources D and D ₁ , transport roller pairs C and C ₁ , infrared lamps E and E ₁ , a plate G, a set of squeegee rollers H and a drive motor F with adjustable speed. The above-mentioned device parts are all arranged in a housing L. The drying chamber is formed by ventilation chambers B and B-. Furthermore, a film receiving or collecting table M is provided.

In Figure 2, the actual drying section is shown in more detail, but still schematically.

The infrared lamps E, E ₁ are each arranged between the pairs of transport rollers C, C. Each infrared lamp E, E ^ is assigned a reflector R, R ₁ with a substantially U-shaped cross section. The reflectors R, R ₁ can be designed so that they have a semi-elliptical cross-section, the filaments of the infrared lamps E, E ₁ lying in one focal point of the ellipse, while the other focal point lies in a plane on which the film to be dried runs along during the drying process.

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The transport rollers C, C. arranged between the individual pairs of infrared lamps E, E _{1 are shielded by screens DF, DF 1 in} order to be certain of preventing overheating of the transport rollers in question, which would have a detrimental effect on the drying process.

The reproduced in Figures 1 and 2 according to the invention The drying device has the following characteristics:

Speed 1 - 2 cm / sec.

Power consumption of the lamps 1.2 KW

Number of lamps 6

Length of the dry bunting 13 cm

3 Total blower capacity 600 m / h

Total power consumption of the fans. 80 W

If an X-ray film soaked with water, e.g. an X-ray film from the applicant of type R, is left in accordance with the usual development, Fixing and washing operations at a rate of 2 cm / second by the one described above run drying device according to the invention, so the X-ray film is quite at the exit from the drying device dry without the temperature differing significantly from the temperature on entry into the drying device has increased.

^T he reference numerals in Figures 3 to 6 each have the same meaning as the reference signs in the figures 1 and 2,

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In the case of the drying device shown in FIG. 3, lead the fans A, A ^ through lines not shown air in Filling chambers G, G. a, from which air through openings L, L., which are forked by the reflectors R, R., against the film to be dried running through the transport rollers C, C. is blown.

This cools the reflectors and effectively shields the transport rollers C, C. from those of the infrared lamps E, E ^ outgoing thermal radiation reached.

In the drying device shown in FIG. 4, the air emerging from the fans A, A. is fed through lines, not shown, to outlet pipes M, K. , which are connected to slot ejectors or nozzles N, h * on their side facing the film transport plane. It should be noted that in this embodiment of the drying device of the invention between the reflectors R, R ₁ and the transport rollers C, C. air is blown through.

In this case too, in addition to the effect on the film to be dried, the air jets also achieve effective cooling of the reflectors R, R ₁ and transport rollers C, C ₁ .

In the embodiment shown in FIG. 5, the _{air coming from the fans A, A 1} is introduced through lines into chambers Q, Q ₁ , from which it emerges in such a way that both the transport rollers C, C ₁ and the film flow against them. This arrangement is most effective in terms of good cooling of the transport rollers C, C ₁ .

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In Figure 6, a further embodiment of the embodiment shown in Figure 5 is shown, in which in the chambers Q, CL U-shaped elements T, T. are arranged, which _{serve to shield the transport rollers C, C 1} and at the same time represent settling surfaces which are in the. Airborne particles can precipitate.

The drying devices of the invention can be used with success in built-in automatic developing systems for X-ray films will. In such a system, the film is processed after the • various stages of work (developing, fixing and washing or soaking), introduced directly into the drying chamber formed with a cover as in Figure 1 and dried. The characteristics of such a drying apparatus depend on the characteristics of the automatic developing equipment in which it is to be installed and, above all, the speed at which it works. At a speed of 1.6 cm / second, which is known to be a processing or development cycle of 90 seconds, the other characteristics preferably have the following "values:

Length of the drying chamber 10-14 cm

Power consumption of the infrared lamps. 800 W

Number of lamps 4

Blower flow rate 400 - 600 m / h

Power consumption of the fan ........ 60 -80 W

Claims i

Claims (10)

Claims f1.) A method for drying photographic films soaked with water by evaporating the water with heat energy supplied from at least one external heat source and removing the water vapor formed thereby with an air stream covering the film to be dried, characterized in that the heat of evaporation for the film to be dried the water to be removed is supplied essentially by irradiation with infrared rays and the film is brushed with a stream of air whose temperature is room temperature, the conditions under which the film to be dried is irradiated with infrared rays and blown with air are selected so, that it is dried without a substantial increase in temperature. 2. The method according to claim 1, characterized in that the film to be dried in a drying chamber between the two Elongated infrared radiation sources arranged at a distance of 1 to 3 cm on the sides of the film transport plane and non-heated air currents directed against the film Temperature at the time of impingement on the film is in the range of 15 to 35 ° C, is carried out. · 3. The method according to claim 1 or 2, characterized in that the air and the infrared rays from physically or spatially separate sources are allowed to act on the film to be dried. 309848/0906 4. The method according to claim 3, characterized in that infrared rays from between two air sources arranged infrared radiation sources can act on the film. 5. The method according to any one of claims 1 to 4, characterized in that that the film irradiated with infrared rays is blown with so much non-heated air that its Temperature increased by no more than 10 C during drying. 6. The method according to any one of claims 2 to 5, characterized in that that the film is fed through .die drying chamber by means of transport rollers. 7. The method according to claim 6, characterized in that the film by means of a series of opposing pairs arranged transport rollers, whose points of contact or lines define the transport plane, through the drying chamber to be led. 8. Drying device for carrying out the method according to one of claims 2 to 7 with an inlet, an outlet and a transport device arranged at least partially in the drying chamber for the drying chamber having the film, characterized in that in the drying chamber (B, B.) on both sides of the film transport level a) elongated infrared radiation sources facing the film transport plane (E, E.) at a distance of 1 to 3 cm and b) air sources directed towards the film transport plane (D, D ^) 309848/0906 for supplying air with a temperature of 15 to 35 ° C are provided. 9. Drying device according to claim 8, characterized in that the infrared radiation sources (E, E.) and air sources (D, D.) are arranged so that the infrared rays and the air during operation on the film from independent and physically or spatially separate sources hit. 10. Drying device according to claim 9, characterized in that each of the infrared radiation sources (E, E ^) between two air sources (D, D-) is arranged. 309848/0906