JPH08144187A - Doctor blade of doctor device - Google Patents

Abstract

PURPOSE: To provide a doctor blade suitable for doctoring on a flexible roll surface such as a rolling roll. CONSTITUTION: This doctor blade 12 of a doctor device is obtained by forming only the side of a blade tip 121 into a thin-wall part 123 and other parts as a whole into a thick-wall part 124. The material of the doctor blade 12 is polyethylene resin which is a soft material in usually used materials. Since the doctor blade 12 is thick as a whole, a sufficient rigidity can wholly be ensured. Since the blade tip is thin, a good blade touch can be formed to realize good doctoring without damaging a flexible roll surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a doctor device used for scraping off foreign substances adhering to the surface of a steelmaking roll such as a rolling roll or a roll of a paper machine. It is about improvement.

[0002]

2. Description of the Related Art Conventionally, an air tube type doctor device shown in FIG. 4 is generally used as a doctor device for a paper machine roll. As shown in this figure, a doctor device 1 supports an elongated rectangular doctor blade 2 having a cutting edge portion that is pressed against a roll surface, a blade holder 3 that holds the proximal end side of the doctor blade 2, and a holder 3 that supports the holder 3. It consists of a doctor back 4 The doctor back 4 is rotatably supported by bearings on the side of a mount (not shown) on which journal shafts 4a attached to both ends thereof are fixedly arranged. A turnbuckle (not shown) is connected between the doctor back 4 and the gantry, and the doctor back 4 can be fixed in an arbitrary rotational position by adjusting the turnbuckle.

The blade holder 3 is supported on the doctor back 4 side in a rotatable state around the connecting rod 3a. A blade opening tube 5 is arranged on the front side of the connecting rod 3a, and a blade pressing tube 6 is arranged on the rear side. These tubes 5,
6 is made of a flexible material, and when the tube 5 side is expanded, the blade holder 3 holding the doctor blade 2 moves the doctor blade 2 away from the surface of the roll R about the connecting rod 3a. That is, it turns in the opening direction. When the other tube 6 is expanded, the blade holder 3 swivels in the direction in which the doctor blade 2 is pressed against the surface of the roll R, that is, in the pressing direction.

The expansion and contraction of these tubes 5 and 6 are
This is done by controlling the supply of air to these. That is, the air supply path from the air source 7 communicates with the tubes 5 and 6 via the pressure regulating valve 8 and the four-way switching valve 9. When the switching valve 9 is set to the switching position shown in the figure, the pressurizing tube 6 expands. Conversely, when the switching valve is switched, the opening tube 5 expands.

As described above, in the conventional general air tube type doctor device, by controlling the supply of air to the pair of tubes 5 and 6, the blade edge of the doctor blade 2 is brought to the surface of the roll R with an appropriate pressure. I try to make pressure contact.

Here, a soft material is known as the doctor blade 2 of the doctor device used for the paper machine roll. For example, a material having a base material of polyethylene resin is known. Since such a synthetic resin material has a lower rigidity than a composite material containing glass fiber, it is generally thicker than a material having a high rigidity by about 3
The thickness is set to about 6 mm to about 6 mm. By increasing the thickness in this way, it is possible to sufficiently secure the pressure contact force (linear pressure) of the blade edge to the roll surface. In a paper machine roll, the linear pressure is generally about 300 to 4
It is set to 00g.

FIG. 5 shows an example of the cross-sectional shape of a doctor blade for a paper machine roll, which is generally used and made of polyethylene base material. As shown in this figure, the cutting edge of the doctor blade 2 has an acute angle of about 30 to 45 degrees, and is set to have a substantially constant thickness as a whole.

[0008]

The doctor device as described above is conventionally used for a paper machine roll.

However, the step of forming a sheet-like material using a roll is not limited to the paper manufacturing industry. For example, in the steel industry, many rolls such as rolling rolls are used.

Also in these rolls, if foreign matter such as dust adheres to the surface of the roll, problems such as unevenness on the surface of the formed sheet occur. As a method of removing the foreign matter attached to the surface of the rolling roll, generally, a method using a brush roll, a method of reciprocating a brush along the roll surface, and the like are adopted. However, it is difficult to reliably remove the foreign matter attached to the roll surface by such a conventional method.

Therefore, using the doctor device described above,
It is conceivable to scrape off foreign matter attached to the surface of the steelmaking roll. However, in the doctor device used for paper machine rolls, the pressure contact force of the blade edge of the doctor blade is about 3
While the amount is 00 g to 400 g, it may be about 20 to 200 g for an iron making roll. The iron-making roll is generally made of a material softer than that of the paper machine roll, and when a high linear pressure is applied to the roll, the roll surface may be damaged. Therefore, the doctor blade of the doctor device used for the steelmaking roll is preferably made of a soft material such as polyethylene resin.

However, when a doctor blade made of a soft material is used, the doctor blade becomes thick in order to secure the required rigidity. That is, as shown in FIG. 6, when the doctor blade made of a soft material is thinned, its out-of-plane rigidity is lowered and the whole is curved, so that a sufficient pressure contact force cannot be applied to the cutting edge. When a thick doctor blade is used as it is, the doctor ring performance is inferior to a thin one. Further, when a thick doctor blade is used, the bending tendency of the doctor blade itself directly affects the roll surface. If you use a hard doctor blade, you can solve such problems because it can be thin, but as mentioned above, the iron roll surface is soft, so using a hard doctor blade causes problems such as scratches on the roll surface. Resulting in.

This point also applies to the case of performing doctoring on the surface of a paper machine roll or a hard roll.
That is, even when the doctor blade is manufactured from a hard material, for example, a metal plate, a material containing glass fiber, the blade edge has better doctor ring performance, but if it is too thin, the rigidity of the whole is insufficient. , The blade edge cannot be pressed against the roll surface with sufficient linear pressure.

In view of the above points, an object of the present invention is to propose a doctor blade capable of performing excellent doctor ring without damaging the roll surface.

[0015]

In order to solve the above-mentioned problems, in the doctor blade of the present invention, the blade thickness on the side where the cutting edge is formed is thin, and the other portions have a thick cross-sectional shape. . By setting in this way, even if the doctor blade is made of a soft material such as polyethylene resin, the overall out-of-plane rigidity can be sufficiently secured, and a thin doctor blade can perform a good doctor ring. Therefore, a good doctor ring can be performed without causing any trouble such as scratching the surface of the soft iron-making roll.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the construction of a doctor device according to an embodiment of the present invention. The doctor device 11 of the present example is also a slender rectangular doctor blade 1 like the conventional device.
2 and a blade holder 13 holding the base end side
And a doctor back 14 supporting the blade holder 13. Journal shafts 141 are fixed to both ends of the doctor back 14, and these journal shafts 141 are rotatably supported on the pedestal 15 side via bearings 16 attached to the pedestal 15.

The edge of the doctor blade 12 on the tip side is a cutting edge 121, and is pressed against the surface S of the high-temperature roll R with a predetermined pressure contact force during operation. The blade holder 13 is a slender rectangular top plate 131.
And a large number of fingers 132 mounted on the back side at regular intervals in the long side direction. Top plate 1
Between the tip of 31 and the tip of finger 132,
The doctor blade 12 is inserted and held there.

A through hole 133 of the connecting rod 141 is formed in the center of the lower surface of the finger 132. On the other hand, on the upper surface of the doctor back 14, bearing brackets 142 of the connecting rod 141 are attached to both ends thereof. The connecting rod 141 is attached in a state of penetrating through the bearing brackets 142 at both ends and the through holes 133 of the fingers 132, and with the rod 141 as the center,
The blade holder 13 is rotatable in an opening direction (arrow A) away from the roll surface S and a pressing direction (arrow B) toward the roll surface S.

The rear side of the connecting rod 141, that is,
On the side away from the roll surface S, an expandable / contractible tube 143 is mounted between the rear surface of the finger 132 and the upper surface of the doctor back 14. When the tube 143 expands, the doctor blade 12 held by the blade holder 13 around the connecting rod 141 pivots in the pressing direction A, and the pressing force of the blade edge 121 against the roll surface S increases.

A lever 145 functioning as a cam follower is integrally attached to the journal shaft 141 attached to the end of the doctor back 14, and this lever 145 is attached.
Extends from the journal shaft 141 toward the side opposite to the doctor blade 12. Tip part 1 of this lever 145
The upper surface of 45 a abuts on a cam surface 171 formed on the outer circumference of the disk cam 17. The cam 17 is an eccentric cam, and the eccentric shaft 172 is rotatably supported by a bearing 173 attached to a fixed position, and has a cam lever for manual operation extending in the radial direction of the eccentric shaft at the other end. 174 is fixed.

As can be seen from FIG. 1 (a), when the cam lever 174 extends vertically upward, the cam surface 171 that is in contact with the upper surface of the lever 145 is in the state of being retracted to the uppermost side. From this state, when the cam lever 174 is turned in the direction indicated by the arrow C to extend vertically downward as indicated by the imaginary line, the cam 17 rotates integrally with this and hits the upper surface of the lever 145. The cam surface 171 that is present is in the state of protruding most downward. As a result, the lever 145 moves downward, and the journal shaft 141 to which it is attached also rotates in the direction of arrow C. Therefore, the entire doctor device 11 turns about the journal shaft 141 in the opening direction A by a predetermined amount.

Here, the rotational moment M due to the own weight of the doctor device 11 about the journal shaft 141 is shown in FIG.
As shown in (a), the position of this journal shaft 141 or the weight distribution of the entire doctor device is set so that it acts in the pressing direction.

As a result, the lever 145 of the doctor back 14 is moved by the rotational moment M which is always acting.
The cam surface 171 of the cam 17 is always pressed by a predetermined force.

Similarly, in the present embodiment, the blade holder 13 is also set so that the rotational moment in the direction of the arrow m is always applied by its own weight about the connecting rod 141, which is the center of rotation. That is, the moment that tries to turn in the opening direction acts. Therefore, when the pressurizing tube 143 contracts, the blade holder 13 swivels in the opening direction following the contraction. In addition, as described above, when the cam lever 174 is turned to the open side,
Following this, the blade holder 13 also turns to the open side.

Next, with reference to FIG. 2, a mechanism for expanding / contracting and cooling the expandable / contractible pressurizing tube 143 will be described. The pressurizing tube 143 is
It is made of a heat-resistant cloth material containing glass fibers.
The cooling water supply pipe 21 is connected to one end thereof, and the cooling water discharge pipe 22 is connected to the other end thereof. The cooling water supply pipe 21 is connected to a cooling water supply source 24 via a flow rate adjusting valve 23. A pressure gauge 25 for measuring the inlet pressure is attached to the cooling water supply pipe 21.

On the other hand, the cooling water discharge pipe 22 is connected to the drain side 27 via the internal pressure adjusting valve 26, and
A pressure gauge 28 for measuring the outlet pressure is attached.

In this example, the cooling water always flows in the tube 143 during operation. Therefore, the tube 143 is not overheated. Further, the supply amount of the cooling water can be adjusted using the flow rate adjusting valve 23 on the inlet side and the internal pressure adjusting valve 26 on the outlet side, whereby the expansion / contraction amount of the tube can be adjusted. In this way, in this example, the cooling water can be used to simultaneously adjust the pressing force of the doctor blade 12 by the tube and cool the tube itself.

The structure and material of the doctor blade 12 used in this example will be described with reference to FIG. In this example, as the material of the doctor blade 12, a soft material is used among the doctor blade materials conventionally used. For example, it is made of polyethylene resin.

The cross-sectional shape of this doctor blade 12 is as follows. The cutting edge 121 has an acute angle of about 30 degrees. The portion continuous with the cutting edge is a thin portion 123 having a thickness of 2 mm. 6m thick in succession to this
A thick portion 124 of m is formed. Thin part 123
The transition portion 125 from the thick portion 124 to the thick portion 124 is a flat surface on the back surface side, but the front surface side is an inclined surface of 30 degrees and is continuous to the front surface side of the thick portion 124. In this example, the rear end portion of the thick portion 124, that is, the blade holder 13
The portion which is completely inserted therein has a thickness of about 3 mm, which is a medium thickness portion 126. The width of the doctor blade 12 in this example is 76 mm, and the length of the thin portion 123 on the tip side is 10 mm. Experiments conducted by the present inventor have confirmed that it is preferable that the length of the thin-walled portion is between about 5 mm and about 10 mm. Also,
When the doctor blade 12 of this example was used to perform a doctor ring on the surface of the iron-making roll at a linear pressure of about 50 to 100 g / cm, good results were obtained.

In the above example, the present invention is applied to a doctor blade for iron-making rolls. However, the present invention can be similarly applied to doctor blades for other rolls. For example, even in the case of a doctor blade formed from a metal plate, a synthetic resin composite material containing glass fibers, if the blade tip side is thinned and the other portions are thickened, the rigidity of the whole can be secured,
A good doctor ring can be realized.

[0031]

As described above, in the doctor apparatus of the present invention, the doctor blade has a cross-sectional shape that is thin only on the cutting edge side. Therefore, it is possible to secure sufficient rigidity while maintaining a good doctor ring. Therefore, according to the present invention, in particular, a doctor blade can be formed by using a flexible material, and a doctor blade suitable for a doctor ring on a soft roll surface such as an iron-making roll can be realized.

[Brief description of drawings]

1A and 1B are diagrams showing a doctor device according to an embodiment of the present invention, in which FIG. 1A is a schematic configuration diagram as seen from a side thereof, and FIG. Is.

FIG. 2 is a configuration diagram showing a cooling water supply control mechanism for a pressurizing tube of the doctor device of FIG.

3 is a cross-sectional view showing a cross-sectional shape of a doctor blade of the doctor device of FIG.

FIG. 4 is a configuration diagram of an air tube type doctor device used for a conventional paper machine roll.

FIG. 5 is a view showing a cross-sectional shape of a conventional doctor blade.

FIG. 6 is an explanatory view showing a curved state of a thin doctor blade.

[Explanation of symbols]

 11 ... Doctor device 12 ... Doctor blade 121 ... Blade edge 123 ... Thin portion 124 ... Thick portion 125 ... Transition portion 126 ... Medium portion 13 ... Blade holder 14・ ・ ・ Doctor back 141 ・ ・ ・ Journal shaft 143 ・ ・ ・ Pressurizing tube 15 ・ ・ ・ Stand 16 ・ ・ ・ Bearing 17 ・ ・ ・ Cam R ・ ・ ・ Roll S ・ ・ ・ Roll surface

Claims (1)

[Claims] 1. A doctor having a doctor blade for scraping off deposits on the surface of a roll such as an iron-making roll, a blade holding portion holding the doctor blade, and a supporting portion supporting the blade holding portion. In the apparatus, the doctor blade is set such that the thickness on the side where the blade edge is formed is about ½ or less of the thickness of other portions.