JPH0681164A - Method for spraying strip surface treating liquid - Google Patents

Abstract

PURPOSE:To assure a specified spraying liquid film thickness and to improve the quality of a coated surface even if the pass speed of a strip varies. CONSTITUTION:A reaction vessel 20 is divided to plural divided zones 21 to 24 and single pumps 25, 26 are communicated with spray headers 12 of the respective divided zones 21 to 24 via shut off valves 21A to 24A provided in each of the respective divided zones. The return flow rates from return routes 27, 31 are controlled in accordance with the zones to be used of the divided zones 21 to 24 to be selectively used by opening of the shut off valves 21A to 24A, by which the specified spray pressure in the used zones are maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for spraying a strip surface treatment liquid.

[0002]

2. Description of the Related Art Conventionally, for example, in a continuous strip coating line, as a pretreatment for a coating process in a roll coater, in order to improve the adhesion of the coating to the strip surface,
With a spraying device as shown in FIG. 4, a reaction treatment liquid (spray liquid) such as zinc phosphate liquid is sprayed on the strip surface to form a film. The spray device is a spray header 2 that sprays the spray liquid pumped by the pump 1.
Are arranged in the reaction tank 3 provided along the strip passage line.

At this time, in the conventional spray apparatus, the length of the reaction tank 3 which one pump 1 serves is long, and the spray flow rate is constant and the flow rate is not adjusted.

[0004]

However, the prior art has the following problems. Since the length of the reaction tank 3 is constant, when the strip passing speed changes, the reaction time of the spray liquid with respect to the strip changes, and an appropriate reaction coating thickness cannot be secured. That is, for example, when the plate passing speed is increased, the reaction time is shortened and the reaction film thickness is reduced.

The above is also one of the reasons that the flow rate of the spray liquid supplied from the pump 1 to the reaction tank 3 is constant. When the flow rate of the spray liquid is changed, the spray pressure is changed, an appropriate striking force on the strip surface cannot be obtained, and uneven processing occurs.

It is an object of the present invention to secure a constant coating film thickness of the spray liquid and improve the quality of the coated surface even if the strip passing speed changes.

[0007]

According to the present invention, a strip header for spraying a surface treatment liquid of a strip is prepared by arranging a spray header for spraying a spray liquid which is pumped by a pump in a reaction tank provided along a strip passage line. In the spray method, the reaction tank is divided into a plurality of divided zones in the strip passage direction, and a single pump can be connected to the spray header of each divided zone through a shutoff valve provided for each divided zone. In addition, a return path is provided on the upstream side of each cutoff valve connection part of the discharge path of the pump, and the return flow rate from the return path is controlled according to the use zone of the divided zone that is selectively used by opening the cutoff valve. , A return flow rate control device for stabilizing the spray pressure in the use zone is provided in the above return path to control the strip passing speed and the strip. Based on the required reaction time of the spray liquid, a usage zone pattern sufficient to secure the required coating film thickness of the spray liquid is determined in advance, and the strip passage speed and the spray for the strip are adjusted according to the strip passage conditions. From the required reaction time of the liquid, an appropriate dividing zone in the reaction vessel is selectively used by using the above-mentioned use zone pattern.

[0008]

[Advantages] Depending on the strip threading conditions, a usage zone that is sufficient to secure the required coating film thickness of the spray solution is selected and used from the strip threading speed and the required reaction time of the spray solution with respect to the strip. It That is, for example, when the stripping speed is high, in order to compensate for the reduction of the reaction time in a unit zone, the number of zones used is increased to secure the required reaction time, and as a result, it is possible to secure the required constant film thickness. To do.

Depending on the selected use zone, the return flow controller can be activated to stabilize the spray pressure in the use zone. Therefore, the striking force on the strip surface can be optimized and the occurrence of uneven processing can be prevented.

[0010]

1 is a schematic view showing an embodiment of the present invention, FIG.
Is a schematic diagram showing a strip continuous coating line, FIG. 3 is a schematic diagram showing a spray header, and FIG. 4 is a schematic diagram showing a conventional example.

As shown in FIG. 2, the continuous strip coating line uses the spray headers 12 above and below the spray device 10 as a pretreatment for the coating process in the roll coater 11 in order to improve the adhesion of the coating material to the strip surface. A reaction treatment liquid (spray liquid) such as zinc phosphate liquid is sprayed on the upper and lower surfaces of the strip 13 to form a film (see FIG. 3).

At this time, in the spray device 10, as shown in FIG.
It is divided into four first to fourth division zones 21 to 24.

An electric shutoff valve 21A, 2 provided with one pump 25 for each of the first and second divided zones 21, 22.
It is possible to communicate with the spray header 12 of each of the divided zones 21 and 22 via 2A. In addition, the other pump 26 is provided in each of the third and fourth divided zones 23, 24 via the electric shutoff valves 23A, 24A.
It is possible to communicate with the spray headers 3 and 24.

Further, each shutoff valve 2 in the discharge path of the pump 25
A return passage 27 is provided on the upstream side of the 1A and 22A connection portions, and a return flow rate control device 30 including an electric return valve 28 and a pressure gauge 29 is provided on the return passage 27.
Is provided. The return flow control device 30 includes the shutoff valve 2
Divided zone 2 used selectively by opening 1A and 22A
The return flow rate from the return path 27 is controlled according to the usage zones 1 and 22 to make the spray pressure constant in the usage zone. This makes it possible to maintain a constant spray pressure in each use zone, whether the division zones 21 and 22 are used alone or simultaneously.

Further, each shutoff valve 2 in the discharge path of the pump 26
A return passage 31 is provided on the upstream side of the 3A and 24A connecting portions, and a return flow rate control device 34 including an electric return valve 32 and a pressure gauge 33 is provided on the return passage 31.
Is provided. The return flow control device 34 includes the shutoff valve 2
Dividing zone 2 selected and used by opening 3A and 24A
The return flow rate from the return path 31 is controlled according to the usage zones of 3 and 24, and the spray pressure in the usage zone is made constant. This makes it possible to maintain a constant spray pressure in each use zone, whether the division zones 23 and 24 are used individually or simultaneously.

At this time, the main controller 35 determines that each shutoff valve 2
1A to 24A and the return valves 28 and 32 are opened and closed.

Then, the main control unit 35 controls the strip 1
Based on the plate passing speed v of 3 and the required reaction time t of the spray liquid with respect to the strip 13, a use zone pattern sufficient to secure a required coating film thickness of the spray liquid is prepared in advance.
For example, it is defined as shown in Table 1.

[0018]

[Table 1]

As a result, the main control unit 35 responds to the strip passage conditions (the strip passage speed v, the required reaction time t of the spray liquid, which is determined by the required adhesion strength of the paint on the strip 13 surface, etc.). Strip 13
From the plate passing speed v and the required reaction time t of the spray liquid with respect to the strip 13, the shut-off valves 21A to 24A and the return valves 28 and 32 are opened / closed by using the use zone pattern in Table 1 above. Appropriate division zones 21 to 24 in the reaction tank 20 are selected and used.

The operation of this embodiment will be described below. Depending on the threading conditions of the strip 13, the strip 13
From the plate passing speed and the required reaction time of the spray liquid with respect to the strip 13, the use zones (21 to 24) sufficient to secure the required coating film thickness of the spray liquid are selected and used. That is, for example, when the stripping speed is fast, in order to compensate for the reduction of the reaction time in the unit zone, the number of zones used is increased to secure the required reaction time, and as a result, it is possible to secure the required constant coating thickness. To do.

Selected usage zones (21-2
Depending on 4), the spray pressure in the use zones (21-24) can be made constant by activating the return flow controllers 30, 34. Therefore, the striking force on the strip surface can be optimized and the occurrence of uneven processing can be prevented.

As an alternative method to the present invention, a pump of the same capacity is provided in each of the divided zones 21 to 24 in a one-to-one manner.
It is also possible to separately drive and control each pump and select and use an appropriate divided zone according to the strip passing conditions. However, the equipment cost will be excessive.

[0023]

As described above, according to the present invention, even if the strip passing speed is changed, a constant spray liquid film thickness can be secured and the quality of the coated surface can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a schematic view showing a strip continuous coating line.

FIG. 3 is a schematic view showing a spray header.

FIG. 4 is a schematic view showing a conventional example.

[Explanation of symbols]

 10 spray device 12 spray header 13 strip 20 reaction tank 21-24 division zone 21A-24A shutoff valve 25, 26 pump 27, 31 return path 30, 34 return flow controller 35 main controller

Claims (1)

[Claims] 1. A method of spraying a strip surface treatment liquid, comprising a spray header for spraying a spray liquid pumped in a pump, the spray header being arranged in a reaction tank provided along a strip passage line. It is divided into a plurality of divided zones in the sheet passing direction of a single pump, and a single pump can be connected to the spray header of each divided zone through a cutoff valve provided for each divided zone. A return path is provided on the upstream side of each shutoff valve connection part, and the return flow rate from the return path is controlled according to the usage zone of the divided zone selected and used by opening the shutoff valve to control the spray pressure in the usage zone. A constant return flow rate controller is installed in the above return path to control the strip passage speed and the required reaction of the spray liquid to the strip. Based on this, the zone of use pattern sufficient to secure the required coating film thickness of the spray liquid is determined in advance, and the strip passage speed and the required reaction time of the spray liquid with respect to the strip depend on the strip passage conditions. From the above, a method for spraying a strip surface treatment liquid, characterized in that an appropriate divided zone in the reaction vessel is selected and used by using the above-mentioned use zone pattern.