JP3432339B2 - Paint dryer booth - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating dryer booth, and more particularly to a thin film strip-shaped support that moves horizontally for drying an organic solvent-based liquid thin film applied to the surface of the thin film strip-shaped support. The present invention relates to a method of using an air curtain in an inert drying type coating dryer booth, which is installed in the middle of a body movement route and is filled with nitrogen gas.

[0002]

2. Description of the Related Art In the process of coating a chemical product, a high temperature environment is required to efficiently dry the coating solution containing the organic solvent applied to the chemical product. However, if an attempt is made to dry the coating solution containing an organic solvent by creating a high temperature environment in the atmosphere, there is a risk of ignition.

The inert drying method is a drying method for safely drying a coating solution containing an organic solvent applied to a chemical product. Oxygen in the dryer room is obtained by filling a dryer room shielded from the atmosphere with nitrogen gas. The thin film-like support coated with the coating solution was conveyed through this dryer room where the concentration was kept below 5% and the temperature was kept at 60 ° C, and the solvent content of the coating solution evaporated in the dryer room was The nitrogen gas is collected and liquefied by a blower installed in the upper part of the dryer room together with the nitrogen gas, and at the same time, the recovered nitrogen gas is separated and returned to the dryer room for drying.

The problem with this inert drying system is to keep the nitrogen gas concentration in the dryer room at a predetermined concentration.
In order to prevent the evaporated solvent component from leaking to the outside of the dryer room, it is necessary to properly block the inside of the dryer room from the outside air at the entrance and exit of the dryer room of the horizontally moving support.

If the interior of the dryer room is not sufficiently shut off from the outside air, the drying efficiency is adversely affected, and the gas of the solvent filled in the dryer room leaks out of the dryer room, so that the surrounding work environment is reduced. This may cause deterioration, or the outside air may flow into the dryer room from the entrance of the dryer room, resulting in a decrease in the nitrogen concentration in the dryer room.

FIG. 7 is a block diagram for explaining a conventional coating dryer booth. 11 is a dryer room (coating dryer booth), 12 is a support, and 13 is an air curtain. For the above-mentioned problems, generally, as shown in FIG. 7, at the entrance / exit of the dryer room 11,
The air curtain 13 is formed by vertically spraying nitrogen gas from above and below the supporting body 12 that moves horizontally, whereby a method of attempting to shut off the inside of the dryer room from the outside air is adopted. ing.

Here, the air boundary layer generated on the surface of a moving object will be described. FIG. 8 is a diagram for explaining an air boundary layer generated near the surface of an object when the object moves in air. 10 is a flat plate, U ₀ is a moving speed of the flat plate 10, and δ is a moving air layer. , U is the flow velocity distribution of moving air. The air boundary layer is a layer of an air flow generated near the surface due to the movement of the object due to the viscosity of the surrounding air when the object moves in the air. As shown in FIG. 8, a region (a region surrounded by a broken line) in which air moves so as to be dragged by the flat plate 10 is formed on the surface of the flat plate 10 that moves leftward in the drawing at a constant velocity U ₀ . According to the fluid dynamics, the flow velocity distribution of this moving air is as shown in FIG.

Assuming that the moving distance of the flat plate is L, the moving speed of the flat plate is U ₀ , the viscosity of air is μ, and the density of air is ρ, the thickness δ of the moving air layer is

[0009]

[Equation 1]

[0010] If the value of k is 4, the moving speed of air at a point δ away from the flat plate is 0.5% of U ₀ .
It becomes the following. That is, if δ is the thickness of the boundary layer, it can be considered that there is an influence of the motion of air in this region. When the coating speed increases, that is, when δ increases, the amount of air dragged by the moving support increases, and when the support goes out of the dryer room, the outflow amount of gas in the dryer room increases and the support When entering the dryer room, the inflow of outside air will increase.

With the recent increase in the speed of the coating process, if the air curtain is simply blown vertically to the support, as described above, the air boundary layer on the surface of the support causes the flow of the air curtain on the support. Since the support is scattered in the moving direction, the outside air is not sufficiently blocked from the inside of the dryer room, which causes a problem that the outside air flows into the dryer room or the gas flows out from the dryer room.

The air curtain is a technique for generating a curtain-like air flow by letting out an air mass from a narrow gap to shut off outside air, shut off heat, and guide air flow. It is widely and commonly used as a partition wall that allows people and things to enter and leave it freely.

Inventions relating to air curtains are disclosed, for example, in JP-A-52-122954 and JP-A-58-1.
39759, JP-A-62-178826,
The one disclosed in Japanese Patent Laid-Open No. 2-116794 is known.

The invention described in the above-mentioned Japanese Patent Laid-Open No. 52-122954 discloses the use of an air curtain formed by an air blowing device having a special double tube structure to scatter mist generated during coating of a chemical product. The air velocity of the air curtain is uniform in the width direction of the slit, and the air velocity does not decrease sharply even if it is far from the blowout part, so this air curtain prevents the scattering of mist that occurs during chemical conversion coating. This makes it possible to maintain a good working environment.

The invention described in JP-A-58-139759 is an upper part of a tunnel-shaped working space formed in a building in a coating booth for coating an object to be coated such as an automobile body with a coating gun. Ventilation air flow to the work space from the work space, and the paint particles and evaporated solvent floating in the work space are discharged to the outside along with the air in the work space near the floor, especially from the exhaust passage formed under the floor plate. The work space is ventilated, and an air curtain-like air flow is supplied from the upper part of the work space between the object to be painted and the paint worker to direct the air from the coating gun to the object to be painted. Of the sprayed paint particles, floating paint particles that do not adhere to the object to be painted and are floating in the air adhere to the object to be painted irregularly, impairing coating quality, or floating paint particles are used for painting work. To adhere to people In which it was to prevent.

The invention described in JP-A-62-178826 is a small space that is shielded from the outside air by a column-shaped swirling airflow generated by a plurality of air curtains formed by being discharged from several blowoff columns. And the forced exhaust of air from one end of this small space converges the swirling airflow into an artificial tornado, which results in harmful gas or harmful particles generated on a relatively wide floor surface or space between the outlet columns. Is to be removed with high efficiency and low cost without diffusing.

In the invention described in Japanese Patent Laid-Open No. 2-116794, the opening is shielded by at least two layers of air curtain, and the air of the air curtain is passed through a filter to remove dust. This prevents dust from flowing into the work chamber.

[0018]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
No. 2-122954, the above-mentioned JP-A-58-13975.
The inventions disclosed in Japanese Patent Laid-Open No. 9 and Japanese Patent Application Laid-Open No. 62-178826 do not consider the influence in the room due to the turbulence of the air curtain caused by an object moving through the air curtain. Further, the invention disclosed in Japanese Patent Laid-Open No. 2-116794 relates to shielding of an opening portion through which an object penetrates and goes in and out of an air curtain, but a room due to disturbance of the air curtain caused by movement of the object It did not consider the airtightness inside.

The present invention has been made in view of the above circumstances, and by devising the structure around the air curtain in the entrance / exit of the coating dryer booth (dryer room), the ambient gas generated on the surface of the support is entrained. The thickness of the layer, i.e. the ambient gas boundary layer (air boundary layer), is reduced to prevent turbulence of the air curtain, and
The purpose of the invention is to provide at low cost a means capable of appropriately blocking the outside air from the interior of the coating dryer booth.

[0020]

According to a first aspect of the present invention, the inside is kept in a nitrogen atmosphere and is installed in the middle of a moving path of a horizontally moving thin film strip-shaped support, and is applied to the surface of the support. In a coating dryer booth for drying a thin liquid organic solvent coating liquid, the coating dryer booth
The support outlet is provided in the vicinity of both sides of the support.
Boundary layer for separating the boundary layer generated near the surface of the carrier
A peeling member is provided, and the boundary layer peeling member is provided on the support inlet side.
There is an air curtain that blows air on both sides of the support.
The pressure of the air curtain
Thus, the support is held, whereby the vibration of the support is suppressed.

[0021] 請 Motomeko second invention is the invention of claim 1, the distance between the boundary layer separation member and said support, 1m
It is obtained by wherein is M～10mm, and physically separate the ambient gas boundary layer generated on the surface of the support to move, the amount of gas in the paint drier booth flow out of paint drier booth It is intended to further suppress.

[0022]

[0023]

[0024]

1 is a block diagram for explaining an application example 1 of a coating dryer booth according to the present invention, in which 1 is a coating dryer booth, 2 is a support, 3 is an air curtain, Immediately before the exit of the coating dryer booth 1, air is blown from above and below to the support 2 that has been dried in the coating dryer booth 1, and the direction in which this air curtain is blown is applied to the support 2. Instead of being vertical, the spray is tilted toward the interior of the paint dryer booth.

As described above, the surrounding gas boundary layer is generated on the surface of the moving support, and the gas flow in this layer is canceled by the air curtain 3 directed so as to face the flow. Accordingly, the thickness of the surrounding gas boundary layer on the surface of the support is reduced, and the amount of gas inside the coating dryer booth 1 flowing out to the outside air together with the support is reduced.

In the example shown in FIG . 1, the horizontal velocity component of the air curtain flow on the support 2 (the velocity component in the direction opposite to the moving direction of the support) is 0.8 times the moving velocity of the support. It is 1.2 times , so that the surrounding gas boundary of the support surface
It is possible to further reduce the thickness of the boundary layer .

In the example shown in FIG. 1 , the air curtain 3 is used.
The angle θ formed between the spraying direction and the support 2 is 70 degrees or less, which prevents the air curtain flow from diffusing on the support 2 toward the outside of the coating dryer booth 1. This is something that can be prevented.

[0028] FIG. 2 is a diagram for explaining the actual施例paint drier booth according to the invention, in FIG, 1 is paint drier booth, 2 the support 4 in the baffle plates, paint drier booth 1 In the vicinity of the outlet of the baffle plate 4, the baffle plates 4 having a right-angled triangular cross section are installed above and below the support body 2 so that the acute angle portions thereof face the moving direction of the support body 2 .
Immediately before, air is blown onto the support 2 from above and below,
(Not shown). Install above and below the support 2
The baffle plate 4 physically separates the gas entrainment layer (surrounding gas boundary layer) generated on the surface of the moving support 2,
The amount of gas in the coating dryer booth 1 flowing out of the coating dryer booth 1 is suppressed.

According to the second aspect of the invention, in the example shown in FIG. 2, the distance D between the baffle plate 4 and the support 2 is 1 mm to 1 mm.
The baffle plate 4 is arranged so as to be 0 mm so that the gas entrained layer can be effectively peeled off.

[0030]

As described above, it is desirable that the baffle plate 4 be as close to the support body 2 as possible.
Vibrates in the vertical direction as it moves, and the vibration may cause the jamming plate 4 to come into contact with the support 2.
Therefore, just before the place where the jammer plate 4 is installed,
Air is blown from above and below the support 2, and the support 2 is held by this pressure to suppress the vibration of the support 2. In this case, since the baffle plate 4 is present, the adverse effect of vertically blowing air does not occur.

FIG. 3 is a block diagram for explaining another application example 2 of the coating dryer booth according to the present invention.
Is a coating dryer booth, 2 is a support, 5 is an air curtain, and the support 2 has an organic solvent-based coating liquid applied on its surface.
On the other hand, immediately after the entrance of the coating dryer booth 1, air is blown from above and below for the purpose of blocking the outside air, and the blowing direction of this air curtain is not perpendicular to the support 2 but toward the outside of the coating dryer booth. It is designed to be tilted and blown.

As described above, the ambient gas boundary layer is generated on the surface of the moving support, and the flow of gas in this layer is extinguished by the air curtain 3 directed so as to face the flow. Accordingly, the thickness of the ambient gas boundary layer on the surface of the support is reduced, and the amount of outside air flowing into the coating dryer booth 1 together with the support is reduced.

In the example shown in FIG . 3, the horizontal velocity component of the air curtain flow on the support 2 (the velocity component in the direction opposite to the moving direction of the support) is 0.8 times the moving velocity of the support. By setting 1.2 times, the surrounding gas boundary of the support surface
It is possible to further reduce the thickness of the boundary layer .

In the example shown in FIG. 3 , the air curtain 3 is used.
The angle θ formed between the spraying direction and the support 2 is 70 degrees or less, which prevents the air curtain flow from diffusing on the support 2 toward the inside of the coating dryer booth 1. This is something that can be prevented.

[0036] The effect of the paint dryer booth according to the present invention, it was confirmed the following experimental examples. (1) Experimental Example 1 FIG. 4 is a diagram for explaining the experimental example 1 for confirming the effect of the paint dryer booth according to the present invention, and shows the velocity distribution of the air boundary layer of the support surface, In the figure, A indicates that the air curtain is not blown to the moving support, B indicates that the air curtain is blown perpendicularly to the moving support, and C indicates that the support moves relative to the moving support. The air curtain was blown at an angle of 45 degrees in the opposite direction.

The moving speed of the support is 1.8 m / s in the horizontal direction, the airflow speed of the air curtain of B is 1.8 m / s, which is equal to the moving speed of the support, and the airflow speed of the air curtain of C. Is set to 2.5 m / s so that its horizontal velocity component is equal to the moving speed of the support (1.8 m / s), and the air curtain is blown from a point 50 mm away from the support, and the flow velocity is It was measured with a hot wire anemometer.

As shown in FIG. 4, the flow velocity u ₁ of the air boundary layer decreases with respect to the distance d ₁ from the support in the order of C, B and A, and the support in the order of C, B and A. It can be seen that the amount of the air entrained layer on the surface, that is, the amount of air moving with the movement of the support is small.

Further, by comparing B and C, it is better to blow the air curtain at an angle of 45 degrees in the direction opposite to the movement of the support, than to blow the air curtain perpendicularly to the support. It can be seen that the amount of air that moves with the movement of the support is small, and the effect of the present invention is great.

[0040] (2) Experimental Example 2 Figure 5 is a diagram for explaining another Experimental Example 2 for confirming the effect of the paint dryer booth according to the invention, the blowing angle of the air curtain θ relative to the support to be moved It shows the relationship of the flow velocity u ₂ of the air boundary layer on the surface of the support, and is the flow velocity of the air boundary layer at a distance of 2 mm from the support at a point 50 mm away from the place where the air curtain was sprayed. Other conditions are: is the same as the conditions of the experimental example 1.

As shown in FIG. 5, under the general coating conditions, the flow velocity u ₂ of the air boundary layer drastically decreases when the spraying angle θ of the air curtain with respect to the support is 70 degrees or less. Therefore, it is understood that the effect for the purpose of the present invention can be expected when the blowing angle θ of the air curtain with respect to the support is 70 degrees or less.

[0042] (3) baffle Experiment Example 3 FIG. 6 is a diagram for explaining still another Experimental Example 3 for confirming the effect of the paint dryer booth according to the invention, which is arranged close to the support to move The velocity distribution of the air boundary layer on the surface of the support with and without the plate is shown. In the figure, a is the velocity distribution of the air boundary layer on the surface of the support without the baffle plate, and b is the baffle plate supported. It is the velocity distribution of the air boundary layer on the surface of the support when the device is installed so that the distance from the body is 0.8 mm.

[0043] If a and b are compared with the distance d ₃ between the support of a and b when to give the same flow rate u _3, the distance d ₃ between the support of b at that time, the support of the time of a About 2 of distance d ₃ from
It is 0%, which means that the thickness of the air boundary layer when the baffle plate is installed is reduced to about 20% of the thickness of the air boundary layer when the baffle plate is not installed.
From this, it is understood that the amount of the air entrained layer that moves with the movement of the support can be suppressed by installing the triangular baffle plate as shown in FIG.

[0044]

According to the first aspect of the present invention, the inside of the liquid organic material is maintained in a nitrogen atmosphere and is installed in the middle of a moving path of a horizontally moving thin film strip-shaped support, and is applied to the surface of the support. In a coating dryer booth for drying a solvent-based coating liquid thin film , a support outlet in the coating dryer booth
Near both sides of the support in the vicinity of the surface of the support
Boundary layer peeling member for peeling the boundary layer generated in the
The boundary layer peeling member on both sides of the support inlet side.
Is obtained by said Rukoto to have a air curtain blowing air to the surface, and physically separate the ambient gas boundary layer generated on the surface of the support to move, paint dryers Boo
It is possible to suppress the amount of gas in the coating dryer booth that flows out of the space. Further, the invention of claim 2, in the invention of claim 1, the distance between the front Symbol boundary layer separation member the support, which was characterized by a 1 mm to 10 mm, the invention of claim 4 The effect of can be further increased .

[Brief description of drawings]

FIG. 1 Application example of a coating dryer booth according to the present invention
FIG. 3 is a configuration diagram for explaining 1 .

2 is a block diagram for explaining the actual施例paint drier booth according to the present invention.

FIG. 3 is an application example of a coating dryer booth according to the present invention
It is a block diagram for explaining 2 .

FIG. 4 is a diagram for explaining Experimental Example 1 in which the effect of the coating dryer booth according to the present invention was confirmed.

FIG. 5 is a diagram for explaining another experimental example 2 in which the effect of the coating dryer booth according to the present invention is confirmed.

FIG. 6 is a diagram for explaining yet another experimental example 3 in which the effect of the coating dryer booth according to the present invention is confirmed.

FIG. 7 is a configuration diagram for explaining a conventional coating dryer booth.

FIG. 8 is a diagram for explaining an air boundary layer generated near the surface of an object when the object moves in the air.

[Explanation of symbols]

1, 11 ... Coating dryer booth, 2, 12 ... Support,
3, 5, 13 ... Air curtain, 4 ... Jammer plate, 10 ... Flat plate, θ, θ ₁ , θ ₂ ... Angle formed by air curtain and support,
D ... distance between the baffle plate and the support, d _1, d ₃ ... distance from the _{support, u 1, u 2, u} 3 ... flow rate of air boundary layer, U ₀ ... flat rate of, u ... air boundary layer Velocity distribution, δ ... Air boundary layer thickness.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F24F 9/00

Claims (2)

(57) [Claims] 1. A nitrogen atmosphere is provided inside, and a thin film strip-shaped support that moves horizontally is installed in the middle of the moving path of the support.
In paint drier booth of drying the coating liquid film of the organic solvent-based liquid applied to the surface of the support, the coating
Both sides of the support at the support outlet in the dryer booth
The boundary layer generated near the surface of the support near the surface.
A boundary layer peeling member for separating is provided, and the boundary layer peeling portion is provided.
Blow air on both sides of the support at the support inlet side of the material
Paint dryer booth and said Rukoto to have a air curtain that. 2. A distance between the boundary layer peeling member and the support.
The coating dryer booth according to claim 1 , wherein the separation is 1 mm to 10 mm .