US2770706A - Method and device of heating spraying agents - Google Patents

Description

Nov. 13, 1956 F. VOGTLE- ET AL 2,770,706

METHOD AND DEVICE OF HEATING SPRAYING AGENTS Filed Feb. 17, 1955 a Sheets-Sheet 1 a p C A P K IHVEPH'DRSI FRIEDRICH V66 Mp TOHAHN V66-7'LE Filed Feb. 17,

- Nov. 13, 1956 F. VOGTLE ET AL 7 METHOD AND DEVICE OF HEATING SPRAYING AGENTS 3 Sheets-Sheet 2 Nov. 13, 1956 F. VOGTLE ETAL 2,770,706

METHOD- AND DEVICE OF HEATING SPRAYING AGENTS Filed Feb. 17, 195; 3 Sheets-Sheet 3 mmvroxs:

rculrcch v c s'Hg a 4 Yvulumsqm United States Patent METHOD AND DEVICE OF HEATING SPRAYING AGENTS Friedrich Viigtle, Ehingen (Danube), and Johann Viigtle, Nesselwangen Kreis Uberlingen (Baden See), Germany Application February 17, 1953, Serial No. 337,294

Claims priority, application Germany February 28, 1952 14 Claims. (Cl. 219-39) special heater and in a stirrer or similar device producing the uniform heating of the spraying agent and preventing a dissociation of the same. Thereafter the spraying agent thus heated will be transmitted to the spraying gun. In the case of flow heaters the spraying agents are transmitt d through heated pipes or through metallic bodies with bores lying side by side, and heated. This method has the particular disadvantage that the heat transfer to the spraying agent is relatively poor and a dissociation of the spraying agent at several bores or pipes can occur in the reversing passages. Moreover, in these cases it is often impossible to obtain the desired quick accommodation of the heat required for the greatly fluctuating spraying conditions. Besides, the cleansing of these devices is complicated.

In accordance with the present invention a method is provided having all of the advantages of hot spraying by heating the spraying agent in the form of a thin film for the quick absorption of heat the spraying agent is spread as a thin film either before or during the heating. In this way the quick transformation of the usually viscous spraying agent into a consistency capable of being atomized is brought about.

With regard to the speed of the process it is, according to a further feature of the invention, indispensable that the amount of heat conducted to the spraying agent is automatically regulated in accordance with the fluctuating amount of spraying agent needed. At the beginning of the spraying process the spraying agent must reach spraying consistency by the fastest possible heating. On the other hand, when the spraying agent is flowing through the sprayer, a reaction of the same speed in the opposite direction is required in order to avoid a detrimental influence of the heat on the spraying agent, such as thickening thereof or'changing of the shade of the spraying agent. In order to bring about this required quick action on the spraying agent, the heating current must be regulated automatically. Moreover, such automatic regulation permits an adjustable constant temperature of the spraying agent. Therefore, when inflammable spraying agents are used there is preferably a low-voltage current applied for regulating, for heating or for both cases.

The spreading of the spraying agents into a thin film is accomplished by forcing the spraying agent to flow along a deflecting body and a heated surface in a thin layer. The spraying substance flows from a hand container or a flow container inserted between a spraying device and a reservoir of the spraying device, such as a spraying gun, to the spraying nozzle or to another atomizer. According to the invention the thickness of the film of the spray- Patented Nov. 13, 1956 ing agent thus obtained is defined by the distance between the deflecting body and the heated surface. It is irrelevant whether the hand container is designed as a gravity container or as a suction container.

The accompanying drawings illustrate different embodiments of apparatus capable of carrying out the present invention. In the drawings:

Fig. 1 is a side view, partially in section, of a spraying gun with a hand-held container;

Fig. 2 is a side view, partially in section, of a spraying gun with a suspended hand-held container;

Fig. 3 is a flow container between the reservoir for the spraying agent and the spraying device;

Fig. 4 is an electrical schematic diagram of a pneumatically operated device for regulating the heating current;

Fig. 5 is an electrical schematic diagram of a heating circuit with a thermo-regulator;

Fig. 6 is a sectional view of a preferred embodiment of the heating surface of the flow container;

Fig. 7 is a plan view of the apparatus shown in Fig. 6; and

Fig. 8 is a side view of a preferred embodiment of a deflecting body used with the flow container.

As will be seen in Fig. 1 there is a spraying agent. container B directly fitted on the spraying gun. At the lowest point 0 of the container, where the spraying agent is emitted, a heating device P is provided surrounding the discharge end at the outside surface of the container B, in a double wall or the like. In the container B a deflecting body C made of a heat-insulating material is mounted and held in such manner that its wall R is spaced the desired distance from the surface A within the area of the heated surface A and is substantially coaxial to it so as to establish a narrow annular gap which defines the thickness of the spraying agent film flowing therethrough. In practice the gap flares outwardly in the flow direction. Next to the heating device or at another point of the container an automatically operating device is arranged for regulating the heating electric circuit. This device preferably contains a thermo-regulator K.

As can be seen in Fig. 2, the container B of the spraying agent is arranged below the gun P. In this embodiment the spraying agent is taken from the lowest point 0 of the container B by means of the rising pipe S. The deflecting body C must serve several purposes. In spraying devices according to Figs. 1 and 2 the deflecting body C divides the container into two sections, viz. into the heated container section with the passage for the spraying agent, and into the larger unheated container section containing the spraying agent supply.

By means of the deflecting body a dissociation of the spraying agent supply, for instance color, due to excessive temperature is prevented. Due to grooves or spirals on the deflecting body or at the heated surface of the container, the spraying agent will be forced to cover an enlarged distance within the heated zone so as to improve the heat transfer between the heated surface and the spraying agent. Such arrangements are shown in Figs. 6, 7 and 8.

With spraying devices, wherein the spraying agent is fed from a reservoir (not illustrated) to the spraying apparatus by means of a pipe T and a flow container U according to Fig. 3, and the discharge side of the container U is heated, the unheated side of the container U facing the upper side of the deflecting body can also be used for transmitting heat.

For easy cleansing of the spraying device the deflecting body is appropriately designed so as to be adapted to be easily removed.

An example of a design of an automatic regulation of the heating electric current is illustrated in Figs. 4 and 5. The solution of the problem requires that the spraying agent must reach spraying consistency by rapid heating at the beginning of the spraying. Also, the heating must be switched off when the spraying is interrupted and the temperature must be adjusted in accordance with the most favorable spraying consistency of the spraying agent. This temperature should not be exceeded nor decreased.

In the illustrated embodiment, this automatic regulation is performed by the compressed air which is necessary for the air atomizing. This same compresesd air is used for regulating the heating current. In the control pipe L, Fig, 5, branched off at a suitable point from the compressed air pipe regulated by the control member V of the spraying gun there is inserted a pneumatically controlled switch E which is actuated by the air flow used for atomizing. The pneumatically-controlled switch E may work by means of a piston or a diaphragm G. Its mode of operation will be seen in Fig. 5. Owing to the air flowing from the compressed air pipe at the beginning of the spraying procedure a difference of pressure is produced in the control pipe at the throttle F which is arranged in a branch piping of the control pipe L and connected in parallel to the switch B. By means of this difference of pressure the diaphragm is actuated so that the electric switch H provided in the heating electric circuit W or in a particular control circuit X is switched on.

At the end of the spraying procedure, that is, when the control pipe L is closed, the pressure is equalized again by the hole I. Therefore, the diaphragm G returns to its starting position so that the switch H is actuated in the reverse direction.

The pneumatically-operated switch H, which may be separated from the container of the spraying agent, is functionally connected with the temperature responsive member K disposed at the hand container B or at the flow container U (Fig. 4). Both of the regulators are series connected in a regulating circuit X. Therefore, the heating device at the hand container or at the flow container is switched on when the air is flowing, on the one hand, whereas, on the other hand, the heating device is switched either on or off, respectively, by the temperature responsive member K when arriving at a maximal temperature or when it falls below the adjusted temperature. Thus the use of the compressed air for regulating the heating electric current results from the necessity of automatically stopping the heating of the spraying agent when the spraying procedure is interrupted. The regulating circuit X contains, by way of example, a relay M acting upon the regulating member (switch) Y of the heating circuit.

The usual reaction of the temperature responsive member K, which is, to operate the switching mechanism in response to heat radiation is far from sufficient in this situation. Accordingly, the temperature responsive member K is equipped with a good conductor of heat, for instance a metallic bridge Z as a heat detector, whereby the temperature in the heating body is quickly transmitted to the temperature responsive member K.

In the case of atomizers wherein the atomizing is not produced by air, instead of the pneumatically-operated switch, a switch connected with the mechanism can be used, which disengages the atomizer.

Because of danger of fire and explosion a great many spraying agents are subjected to legal regulations during the spraying operation. In these cases heating the spraying agent flowing from the reservoir supply or from the flow heater to the atomizer would not be possible as the observance of the legal regulations would result in constructional dimensions and weights which cannot be realized with hand devices. To arrive, nevertheless, at a prac tical solution of the problem, a low voltage (transformer Tr) is used for regulating the heating device, and the part of the automatic control which can be dispensed with in the hand device is arranged in an apparatus separated from the hand device. However the hand device is connected with it by air and electric lines. In this way the attachments to be mounted have constructional dimensions and weights which permit the attachments to be used in hand devices, too.

What is claimed is:

1. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby, and having surface portions defining a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means associated with said vessel means outside thereof for heating said laminar passage so as to heat the film of fluid material flowing therethrough.

2. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion spaced from the inner surface of said vessel means and defining therewith a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means associated with said vessel means for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough.

3. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion spaced from the inner surface of said vessel means and defining therewith a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means at the outer surface of said vessel means for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough.

4. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion adjacent said outlet thereof spaced from the inner surface of said vessel means and defining therewith a laminar passage adjacent said outlet thereof through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means at the outer surface of said vessel means adjacent said outlet thereof for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough.

5. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion adjacent said outlet thereof spaced from the inner surface of said vessel means and defining therewith an annular laminar passage adjacent said outlet thereof through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means at the outer surface of said vessel means adjacent said outlet thereof for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough.

6. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; defleeting means arranged in said vessel means and having a guide surface portion adjacent said outlet thereof spaced from the inner surface of said vessel means and defining therewith an annular laminar passage adjacent said outlet thereof through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means at the outer surface of said vessel means adjacent said outlet thereof for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough, said heating means being substantially coextensive with said laminar passage.

7. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means arranged above said spraying means and having an inlet and an outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion adjacent said outlet thereof spaced from the inner surface of said vessel means and defining therewith an annular laminar passage adjacent said outlet thereof through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means at the outer surface of said vessel means adjacent said outlet thereof for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough, said heating means being substantially coextensive with said laminar passage.

8. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means arranged below said spraying means and having an inlet and an outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion adjacent said outlet thereof spaced from the inner surface of said vessel means and defining therewith an annular laminar passage adjacent said outlet thereof through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means at the outer surface of said vessel means adjacent said outlet thereof for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough, said heating means being substantially coextensive with said laminar passage.

9. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion adjacent said outlet thereof spaced from the inner surface of said vessel means and defining therewith an annular laminar passage adjacent said outlet thereof through which the fluid material is forced to flow in a thin film in its flow toward said spraying means, the outer surface of said deflecting meansbeing substantially parallel to the inner surface of said vessel means; and heating means at the outer surface of said vessel means adjacent said outlet thereof for heating the inner surface thereof along said laminar passage for heating the film of 3 fluid material flowing therethrough, said heating means being substantially coextensive with said laminar passage.

10. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby; deflecting means of heat insulating material arranged in said vessel means and having a guide surface portion spaced from the inner surface of said vessel means and defining therewith a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; and heating means associated with said vessel means for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough.

11. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet, and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing thcrethrough to said spraying means for spraying thereby; deflecting means arranged in said vessel means and having a guide surface portion spaced from the inner surface of said vessel means and defining therewith a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means, at least one of the surfaces defining said laminar passage being configured for increasing the total surface area thereof; and heating means associated with said vessel means for heating the inner surface thereof along said laminar passage for heating the film of fluid material flowing therethrough.

12. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby, and having spaced surface portions defining a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; heating means associated with said vessel means outside thereof for heating said laminar passage so as to heat the film of fluid material flowing therethrough; and operating means for starting and stopping the operation of said spraying means and said heating means simultaneously.

13. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet and being connected at its outlet to said spraying means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby, and having spaced surface portions defining a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; electrical heating means associated with said vessel means outside thereof for heating said laminar passage so as to heat the film of fluid material flowing therethrough; and operating means for starting and stopping the operation of said spraying means and said heating means simultaneously, said operating means including an electrical circuit having thermo-regulator means and switch means operable thereby for operating said heating means.

14. A spraying device, comprising, in combination, spraying means for spraying fluid material under pressure; vessel means having an inlet and an outlet and being connected at its outlet to said sprayig means, said vessel means being adapted to contain fluid material flowing therethrough to said spraying means for spraying thereby, and having spaced surface portions defining a laminar passage through which the fluid material is forced to flow in a thin film in its flow toward said spraying means; electrical heating means associated with said vessel means outside thereof for heating said laminar passage so as to heat the film of fluid material flowing therethrough; and operating means for starting and stopping the operation of said spraying means and said heating means simultaneously, said operating means including an electrical circuit haying thermo-regulator means and switch means operable thereby for operating said heating means, said operating means further including compressed fluid supply means operatively connected to said spraying means, and regulating means for controlling the flow of compressed fluid in said supply means; said switch means being operable by said regulating means for stopping and starting the operation of said heating means.

References Cited in the file of this patent UNITED STATES PATENTS Steckel et a1. Jan. 19, Holmes Feb. 13, Albertson May 5, Gillespie May 9, West Jan. 16, Denyssen Jan. 27, Parsons et a1 Apr. 27,

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