JP3174746B2 - Doctor device - Google Patents

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 paper debris or the like adhered to the surface of a roll such as a paper machine roll.

[0002]

2. Description of the Related Art As a doctor device, a tube pressurizing type shown in FIG. 3 is known. This doctor device 1
Is basically composed of a doctor blade 2 pressed against the surface 101 of the roll 100, a blade holder 3 holding the doctor blade 2, and a doctor back 4 supporting the blade holder 3. Support shafts 4a are attached to both ends of the doctor back 4, and these support shafts 4a are rotatably supported by support brackets (not shown) installed at fixed positions. The doctor back 4 is fixed at an appropriate rotational position so as not to rotate by a fixture such as a turnbuckle (not shown).

The doctor blade 2 has an elongated shape having a length substantially equal to the surface length of the roll 100, and its blade edge 2a is pressed against the roll surface 101 at a predetermined linear pressure, and the roll 100 is rotated in this state. Then, foreign matter such as paper residue adhering to the roll surface 101 is scraped off by the blade edge 2 a of the doctor blade 2.

[0004] The blade holder 3 includes a top plate 31.
A plurality of finger plates 32 attached to the back surface of the top plate 31 at regular intervals; and a support rod 33 extending through a rod hole projecting downward from the center of the lower surface of the finger plate 32.
And a bottom plate 34 arranged below the finger plate 32. Bottom plate 34
Are formed at both ends in the longitudinal direction thereof with rod support portions (not shown) bent upward.
3 are rotatably supported at both ends.

[0005] At the front end of each finger plate 32, a protruding portion 32 a is formed whose upper end is bent upward at a right angle. The protruding portion 32 a and the top plate 3
The front end portion 2b of the doctor blade 2 is inserted between the front end portion 31a and the front end portion 31a. In addition, a pair of air tubes 36 and 37 are arranged between each finger plate 32 and the bottom plate 34 with the support rod 33 interposed therebetween. The front air tube 36 is an opening air tube, and the rear air tube 37 is a pressurizing air tube. The bottom plate 34 is supported on the doctor back 4 side.

[0006] By rotating the blade holder 3 having the above configuration back and forth around the support rod 33, the linear pressure (pressure contact force) of the blade edge 2a of the doctor blade 2 against the roll surface 101 can be adjusted. That is, the air tubes 36 and 37 are connected to the flow path switching valve 83 via the air supply paths 81 and 82. The switching valve 83 is connected to an air supply source 85 via a pressure reducing valve 84. When the switching valve 83 is at the switching position shown in FIG. 3, air is supplied to the pressurizing air tube 37 and air is discharged from the opening air tube 36. As a result, the pressurizing air tube 37 expands and the opening air tube 36 contracts, so that the doctor blade 2 rotates forward around the support rod 33 and the cutting edge 2
The pressing force (linear pressure) of a on the roll surface increases.

When the switching valve 83 is switched, on the contrary, the opening air tube 36 expands and the pressurizing air tube 37 contracts, so that the doctor blade 2 rotates backward, and the pressure contact force is weakened. Opening air tube 3
6 is further expanded and the pressurizing air tube 37 is further contracted, so that the doctor blade 2 can be separated from the roll surface 101.

[0008]

During doctoring of the surface 101 of the roll 100 rotating in the direction indicated by the arrow A in the figure, the doctor blade 2 was scraped off by the cutting edge 2a of the doctor blade 2 pressed against the roll surface 101. Foreign matter, liquid, and the like accumulate on the upper surface 21 of the doctor blade 2.
When a foreign substance or the like wraps around the opening tube 36 located on the roll side and enters between the support rod 33 which is the center axis of rotation of the doctor blade 2 and the bearing portion supporting the support rod 33, The smooth turning of the doctor blade 2 is hindered, and in some cases, the turning becomes impossible.

In the figure, the roll 10 is moved in the direction indicated by arrow A.
When 0 rotates, the scraped foreign matters and the like accumulate on the upper surface 21 of the doctor blade 2 and the top plate 31, and these plates cause paper waste to be placed on the opposite side of the support rod 33. Are prevented from wrapping around.

[0010] However, as shown in FIG.
During doctoring when the roll 100 rotates in the direction of the arrow, paper residue and the like accumulate on the lower surface 22 of the doctor blade 2,
It easily enters the support rod 33 side beyond the opening tube 36. As a result, a smooth turning operation of the doctor blade 2 is hindered, and as a result, a situation in which proper doctoring cannot be performed may occur.

An object of the present invention is to propose a doctor device capable of avoiding such adverse effects.

[0012]

FIG. 1 shows the configuration of a doctor device according to the present invention. As shown in this figure, a doctor device 51 includes a doctor blade 52 having a cutting edge 52a pressed against a roll surface 101, a blade holder 53 for holding the doctor blade 52, and a support for supporting the blade holder 53. Means 54.

The blade holder 53 is provided with a pressurizing tube 5.
37 and the opening tube 536 are expanded and contracted so that the doctor blade 52 is brought into contact with the roll surface 10.
It is configured to pivot to a position where it is pressed against 1 and a position away from the roll surface 101. Pneumatic circuits for expanding and contracting the pressurizing air tube 537 and the opening air tube 536 are the same as those shown in FIG.

Here, the blade holder 53 includes a support plate 531, a plurality of fingers 532 attached to the upstream surface 531 a of the support plate 531 in the roll rotation direction B, a support plate 531 and a finger 532.
A blade insertion portion 55 for detachably inserting and fixing the doctor blade 52 constituted by the above-mentioned components, and a turning center axis 533 of the doctor blade 52 arranged on the surface 531b opposite to the support plate 531 are provided.

The above-described pressurizing air tube 537 is disposed closer to the doctor blade 52 than the turning center shaft 533. An opening air tube 536 is arranged at a position opposite to the pressurizing air tube 537 with respect to the turning center shaft 533.

Next, as shown enlarged in FIG. 2, the cutting edge angle of the cutting edge 52a of the doctor blade 52 of the present invention is set to 90 degrees. The blade contact angle θ of the doctor blade 52 with respect to the roll surface 101 is set to a value between 30 degrees and 60 degrees.

The thus configured doctor device 51 of the present invention is disposed with respect to the roll 100 as shown in FIG. When the roll 100 rotates in the direction of arrow B, doctoring of the roll surface 101 is performed by the cutting edge 52a of the doctor blade 52 that is in contact with the roll surface 101.

The paper scraps and the like scraped off by the doctor ring accumulate on the surface 52c of the doctor blade 52. A support plate 531 is disposed on the side of the surface 52 b opposite to the doctor blade 52. Therefore, the two plates 52 and 531 prevent the liquid containing paper residue and the like accumulated on the surface 52c of the doctor blade 52 from entering the opposite side of the turning center shaft 533. Therefore, it is possible to avoid a problem that paper waste or the like enters the side of the turning center axis 533 and hinders smooth turning of the doctor blade 52.

According to the experiment of the inventor, the blade angle of the doctor blade 52 is set to 90 degrees, and the blade contact angle θ is set.
When doctoring was performed with the blade edge 52a of the doctor blade applied to the roll surface 101 so that the angle was 30 to 60 degrees, it was confirmed that excellent doctoring was possible.

In a conventional doctor device, generally,
The blade contact angle of the doctor blade 2 is set to a value within the range of about 25 degrees to 30 degrees. When the doctor ring was rotated (reversely rotated) in the direction of arrow B at a blade contact angle in this range to perform doctoring, it was confirmed that appropriate doctoring could not be performed. In the present invention, as shown in FIG. 2, the doctor blade 52 is tilted to the upstream side in the roll rotation direction, and the angle θ is set to be 30 degrees to 60 degrees. It has been confirmed that such setting makes it possible to realize excellent doctoring.

[0021]

As described above, in the doctor device according to the present invention, the doctor blade is provided between the surface of the doctor blade on which the paper scraps scraped off by the doctor blade are accumulated and the center axis of rotation of the doctor blade. And a support plate, which is divided by two plates. Therefore, according to the present invention, the liquid including the paper scraps scraped off by the doctor blade enters the side of the turning center axis, and the smooth turning operation of the doctor blade is hindered. Can be avoided.

In the doctor device of the present invention,
Set the blade angle of the doctor blade to 90 degrees,
Since the angle between the roll surface and the doctor blade is set in the range of 30 degrees to 60 degrees, excellent doctoring can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a doctor device to which the present invention is applied.

FIG. 2 is an explanatory view showing a shape of the doctor blade of FIG. 1 and a contact angle of the doctor blade with respect to a roll.

FIG. 3 is a schematic configuration diagram showing a conventional tube pressurized doctor device.

4 is an explanatory diagram showing the shape of the doctor blade of FIG. 3 and the contact angle of the doctor blade with respect to a roll.

[Explanation of symbols]

 Reference Signs List 51 doctor device 52 doctor blade 52a blade edge of doctor blade 52b surface of doctor blade 52c surface opposite to doctor blade 53 blade holder 531 support plate 532 finger 533 turning center axis 536 opening air tube 537 pressurizing air tube 55 insertion portion 54 Doctor back θ Angle per blade

Claims (3)

(57) [Claims] 1. A doctor blade having a cutting edge pressed against a roll surface, a blade holder for holding the doctor blade, and supporting means for supporting the blade holder, wherein the blade holder is provided with a pressurizing blade. A doctor device configured to swivel the doctor blade to a position pressed against the roll surface and a position separated from the roll surface by expanding and contracting a tube and an opening tube, wherein the blade holder includes: A support plate extending along the doctor blade, a finger attached to an upstream surface of the support plate in the roll rotation direction, and a blade for detachably inserting and fixing the doctor blade constituted by the support plate and the finger The insertion part and the support press A center axis of rotation of the doctor blade arranged on the side of the surface on the opposite side of the blade, the tube for pressurization arranged on the doctor blade side of the center axis of rotation, and the rotation center axis. A doctor device, comprising: a pressurizing tube; and the opening tube disposed on a side opposite to the pressing tube. 2. The doctor device according to claim 1, wherein a cutting edge angle of the cutting edge of the doctor blade is 90 degrees. 3. The doctor blade according to claim 2, wherein a contact angle of the doctor blade with respect to the roll surface is 30 degrees to 6 degrees.
A doctor device characterized in that the value is between 0 degrees.