JP3907306B2 - Multi-stage doctor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a doctor device used for writing off foreign matter adhering to the surface of a paper machine roll, a rolling roll or the like. More specifically, the present invention relates to a multi-stage doctor device configured to perform doctoring by at least first and second doctor blades.
[0002]
[Prior art]
A doctor device is used to remove foreign substances such as paper bags adhering to the surface of a paper machine roll or the like. For example, Japanese Utility Model Laid-Open No. 6-39999 discloses an air tube type doctor support device capable of bringing a doctor blade into contact with a roll surface with an appropriate pressure contact force using a pair of air tubes. . Japanese Utility Model Publication No. 57-50318 discloses a doctor blade holder device having a holding portion for holding a doctor blade without using an air tube.
[0003]
As such a doctor device, in order to improve doctor ring performance, a multi-stage type device in which doctor blades are arranged in multiple stages along the outer peripheral surface of the roll has been proposed.
[0004]
FIG. 3 shows a typical example of a two-stage doctor device. As shown in this figure, the doctor device 1 includes first and second doctor blades 2 and 3. The first doctor blade 2 is in contact with the upstream roll surface 4a in the rotational direction of the roll 4, and the second doctor blade 3 is in contact with the downstream side of the roll surface 4a. The first and second doctor blades 2 and 3 are respectively held by air tube type blade holders 5 and 6 having the same structure as that disclosed in the above-mentioned public utility model gazette. The blade holders 5 and 6 are supported by a doctor back 7.
[0005]
The doctor back 7 is supported by a stationary member 10 through journal shafts 8 attached to both ends so as to be rotatable about the journal shaft center 8a. The rotation of the doctor back 7 is restrained by a turn buckle 11 that connects the tip of the horizontal arm 9 connected thereto to the fixed member 10.
[0006]
Here, the back side of the first doctor blade 2 is used so that fine foreign matter that has not been scraped off by the first doctor blade 2 can be surely scraped off from the roll surface 4a by the second doctor blade 3. A chemical solution spray nozzle 12 is disposed in the case. The first doctor blade 2 is in contact with the upstream roll surface 4a in the rotational direction of the roll 4, and the second doctor blade 3 is in contact with the downstream side of the roll surface 4a.
[0007]
In the conventional multistage doctor apparatus, the turning of the doctor back , which is the support portion, is restrained by a turnbuckle. Therefore, for example, when performing the cleaning operation of the second doctor blade 3 located on the downstream side in the roll rotation direction or the operation of removing a paper jam generated between the doctor blades 2 and 3, As shown in FIG. 3B, the doctor blade 2 is separated from the roll surface 4a by supplying air to the air tube, and a cleaning operation or the like is performed from the gap G formed thereby.
[0008]
[Problems to be solved by the invention]
However, in the conventional system in which the doctor blade is separated from the roll surface by the air tube type blade holder, the doctor blade is completely separated from the roll surface by about 30 cm. In such a gap, it is extremely difficult to perform the cleaning operation of the surface of the second doctor blade 3 or the cleaning operation of the nozzle.
[0009]
That is, since such work needs to be performed with a hand from the gap between the first doctor blade and the roll surface, the work in such a state is difficult because the gap is narrow, There is a problem that the efficiency is poor because the portion cannot be directly observed.
[0010]
Here, without relying on the air tube, it is possible to remove the turnbuckle and swivel the doctor back, thereby sufficiently retracting the doctor blade from the roll surface. In this case, as shown in FIG. 3B, the locus B of the cutting edge of the second doctor blade 3 on the rear stage side may intersect the roll surface 4a. That is, the blade edge of the doctor blade may interfere with the roll surface, and the doctor blade may not be able to retract from the roll surface.
[0011]
An object of the present invention is to propose a multi-stage doctor device capable of eliminating such adverse effects.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a first doctor blade, a second doctor blade, a blade holding unit that holds the first and second doctor blades, and the blade holding unit. In a multistage doctor apparatus having a doctor back that supports the swivel and a restraining member that restrains the swiveling of the doctor back , the following configuration is adopted.
[0013]
That is, when the second doctor blade is disposed downstream of the first doctor blade in the rotation direction of the roll, the cutting edge of the second doctor blade is the edge of the roll. the position corresponding to the surface, is set so that the line connecting the rotational center of the doctor back pivot with said roll. Moreover, the structure which consists of a hydraulic pressure or an air cylinder attached between the said doctor back and a stationary-side member is employ | adopted as the said restraint member.
[0014]
In the multistage doctor device of the present invention configured as described above, a hydraulic or air cylinder capable of arbitrarily taking a stroke is employed as the restraining member, so that the doctor back is sufficiently swiveled around its swivel center. Thus, each doctor blade can be retracted to a position sufficiently away from the surface of the roll. Moreover, if the contact position with respect to the roll surface of the 2nd doctor blade is prescribed | regulated like this invention, the bad point that the cutting edge of a 2nd doctor blade will interfere with a roll surface and sufficient rotation cannot be ensured does not generate | occur | produce.
[0015]
Therefore, according to the present invention, in the multi-stage doctor apparatus, the work of eliminating the paper jam between the first and second doctor blades, the clogging of the chemical spray nozzle arranged between them, etc. Since it can carry out through a clearance gap, it becomes possible to carry out easily and efficiently compared with the past.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0017]
FIG. 1A is a schematic configuration diagram of a two-stage doctor apparatus to which the present invention is applied. The two-stage doctor device 21 of the present example includes first and second doctor blades 22 and 23. The first doctor blade 22 is in contact with the upstream roll surface 4a in the rotation direction of the roll 4, and the second doctor blade 23 is in contact with the downstream side of the roll surface 4a.
[0018]
The first and second doctor blades 22 and 23 are respectively held by air tube type blade holders 25 and 26 having the same structure as that disclosed in the aforementioned published utility model publication. That is, as shown in FIG. 1B, each blade holder 25 (26) includes an air tube 41 for pressing the doctor blade 22 (23) against the roll surface 4a and the doctor blade 22 (23) against the roll surface 4a. And an air tube 42 for separating from the air tube.
[0019]
By adjusting the supply air amount and the exhaust air amount to the pair of air tubes 41, 42, the doctor blade 22 (23) is turned around the turning center shaft 43 and pressed against the roll surface with an appropriate pressure contact force. In addition, the doctor blade 22 (23) can be released from the roll surface 4a in order to clean the doctor blade.
[0020]
The blade holders 25 and 26 may be configured to have a single air tube instead of a pair of air tubes. Further, a blade holder having a structure disclosed in the above-mentioned public utility model gazette can also be adopted.
[0021]
These blade holders 25 and 26 are supported by a doctor back 27. The doctor back 27 is supported by the stationary member 11 via journal shafts 28 attached to both ends so as to be rotatable about the journal shaft center 28a. One end of a connecting arm portion 29 extending in the radial direction is attached to the journal shaft 28 of the doctor back 27. The other end of the connecting arm 29 is connected to the tip of the hydraulic rod 30a of the hydraulic or air cylinder 30. The cylinder 30 is fixed to the stationary member 11 and functions as a restraining member that restrains the doctor back 27 from turning.
[0022]
Also in the doctor device 21 of this example, a spray nozzle 32 for spraying a chemical solution is disposed at a position between the doctor blades 22 and 23. A chemical solution for facilitating peeling of paper sheets or the like is sprayed from the nozzle 32 toward the roll surface on the back surface side of the cutting edge of the first doctor blade 22.
[0023]
Here, the cylinder 30 that functions as the rotation restraining member of the doctor back 27 has a stroke of, for example, about 500 mm. Therefore, the extension of the cylinder 30 allows the doctor back 27 to be swung over a wide angle range around the center 28a.
[0024]
Moreover, in the doctor apparatus 21 of this example, the position P where the cutting edge 23a of the second doctor blade 23 hits the surface 4a of the roll 4 is set as follows. That is, the journal axis center 28a of the doctor back 27, so that the top of the line segment L connecting the rotation center of the roller 4 (not shown), is set to the position P.
[0025]
In the two-stage doctor device 21 having this configuration, the doctor back 27 is turned around the center 28a by the cylinder 30 and the doctor back 27 is fixed at an appropriate turning position. Next, the amount of air supplied to the air tubes of the blade holders 25 and 26 is controlled, and the blade edges of the doctor blades 22 and 23 are pressed against the surface 4a of the roll 4 with an appropriate pressure contact force. When the roll 4 rotates in the arrow direction in this state, the foreign matter attached to the roll surface 4a is scraped off by the doctor blades 22 and 23.
[0026]
Here, when a paper jam occurs between the doctor blades 22 and 23 or when a nozzle clog occurs, the operating rod 30a of the cylinder 30 is moved to the maximum retracted position. As a result, as shown in FIG. 2, the doctor back 27 turns around the journal shaft center 28a. The doctor blades 22 and 23 held by the blade holders 25 and 26 supported by the doctor back 27 also turn in a direction away from the roll surface 4a.
[0027]
Here, the trajectory A of the blade edge 23a of the doctor blade 23 does not intersect the arc that defines the roll surface 4a. That is, unlike the case shown in FIG. 3B, a situation in which the blade tip of the doctor blade hits the roll surface and cannot turn does not occur.
[0028]
As a result, the gap G1 between the first doctor blade 22 on the upper stage side and the roll surface 4a is sufficiently wide to perform the work. Further, the gap between the doctor blades 22 and 23 can be directly observed from the horizontal direction.
[0029]
Therefore, according to the two-stage doctor device 21 of this example, the maintenance and inspection work for eliminating the paper jam between the doctor blades 22 and 23 and the nozzle clogging is performed more easily and efficiently than in the past. be able to.
[0030]
The present invention can be applied not only to a two-stage doctor apparatus but also to a three-stage doctor apparatus. In this case, the contact position of the blade edge of the doctor blade located on the most downstream side in the roll rotation direction with respect to the roll surface may be set as in the second doctor blade 23 described above.
[0031]
【The invention's effect】
As described above, in the multistage doctor device of the present invention, the doctor back is swung using a hydraulic or air cylinder having a long stroke, and the doctor is swung over such a large angle range. An arrangement relationship between the doctor blade and the roll surface is employed so that the blade does not interfere with the roll surface.
[0032]
Therefore, according to the present invention, according to the two-stage doctor device 21 of this example, the maintenance inspection work for eliminating the paper jam between the doctor blades 22 and 23 and the nozzle clogging has been conventionally performed. Compared to this, it can be performed easily and efficiently.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a two-stage doctor apparatus to which the present invention is applied.
FIG. 2 is an explanatory diagram for explaining an operation of the doctor device of FIG. 1;
FIG. 3 is a schematic configuration diagram showing a conventional two-stage doctor device, and an explanatory diagram showing its problems.
[Explanation of symbols]
4 Roll 4a Roll surface 21 Doctor device 22 First doctor blade 23 Second doctor blade 23a Cutting edge 25, 26 Blade holder 27 Doctor back 28 Journal shaft 28a Journal shaft center 29 Connecting arm 30 Hydraulic or air cylinder 30a Actuating rod L Line segment P connecting the center of the roll and the center of the journal axis Contact position of the cutting edge of the second doctor blade with the roll surface

Claims (2)

A first doctor blade, a second doctor blade, a blade holding portion holding the first and second doctor blades, a doctor back supporting the blade holding portion in a pivotable manner, In a multistage doctor device having a restraining member that restrains swiveling of the doctor back ,
The second doctor blade is disposed on the downstream side in the rotation direction of the roll with respect to the first doctor blade,
Position corresponding to the surface of the cutting edge of the second doctor blade is the roll is set to be on a line connecting the rotational center of the doctor back pivot with said roll,
The multi-stage doctor device characterized in that the restraining member includes a hydraulic or air cylinder attached between the doctor back and the fixed side member. In Claim 1, The said blade holding | maintenance part is a structure provided with at least any one of the air tube for pressing a doctor blade against the surface of a roll, and the air tube for separating a doctor blade from the surface of a roll. A featured multistage doctor device.

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