JP2007530801A - Elastic doctor - Google Patents

Abstract

  The elastic doctor has a special purpose of removing unnecessary materials during the roll operation on the surface of the roll (2) used in the paper manufacturing industry. The blade (8) is attached to the blade holder (1). The device has working means (eg 6, 7) that produce the desired pressure of the doctor blade against the roll. With respect to the longitudinal direction, the blade (8) is curved at least part of its length.

Description

Detailed Description of the Invention

  The present invention relates to an elastic doctor, and more specifically to a doctor that cleanly scrapes unnecessary deposits on various rolls of paper manufacturing equipment.

  The normal structure and positioning of the doctor is such that the doctor blade is placed at a specific pressure against the surface of the roll that is the subject of the doctor, removing fibers and other substances attached to the roll from the surface, The doctor blade is usually about 75 to 85 mm in length and has a desired width, that is, essentially the same width as the roll that is the subject of the doctor. When the blade is new, the contact angle of the blade to the surface of the roll is often about 25 degrees, but as the blade wears, the adhesion angle changes and the blade is replaced. Immediately before, the angle is about 35 degrees.

  The length of the doctor blade immediately before the replacement is about 60 mm. Thus, the blade surface pressure varies due to blade wear. In fact, it has also been noted that with the current blade structure style, the possibility of increasing the wear margin per blade length is very small. This is because of problems caused by blade deflection. Even when the pressure of the blade increases, the same problem is caused, and a gap is generated at the tip of the blade, and the tip of the blade does not adhere to the roll surface. As a result, unnecessary deposits are not removed.

  The blade defects in the prior art have led to various compromises in blade manufacture, and avoiding the blade defects has improved the quality of the blades produced.

  In a paper making machine, the doctor blades are changed approximately every week. Although the replacement itself is not a difficult operation, the replacement operation takes about one hour, the manufacturing cost easily increases to about 20,000 euros, and the replacement operation is expensive. Therefore, prolonging the blade replacement interval easily provides considerable cost effectiveness in paper manufacture.

  The present invention aims to create a new and improved doctor blade structure which makes it possible to avoid and save the drawbacks that have always existed in the prior art in the manufacture of paper.

  The above objects and other advantages and advantages of the invention are achieved in the manner described as characteristic in the appended claims.

  Accordingly, the present invention will be discussed in more detail below with reference to the accompanying schematic drawings showing one specific example of the present invention.

FIG. 1 shows a blade carrier, blade holder and blade according to the invention in a full size with no wear on the blade,
FIG. 2 shows the same structure as FIG. 1 and shows a state in which the blade is somewhat worn until it needs to be replaced.

  The roll that becomes the surface from which the unnecessary objects are removed by the doctor blade is the member number 2 in the figure, and as shown in the figure, in this embodiment, the roll 2 having a relatively large diameter is considered. The surface of roll 2 in FIG.

  The blade holder 1 is somewhat conventional in structure. The blade holder 1 is in the form of a frame structure that is attached to the frame structure of, for example, a paper manufacturing machine so that it cannot be removed. The frame 5 of the blade holder 1 has a protrusion 3 for the shaft 4. The blade holder 1 is installed with the shaft 4 as a central axis, and can be rotated around the shaft 4 within a certain range by control. The above control is made in order by using the hose-like components 6 and 7. The hose-like components 6 and 7 are filled with a pressure medium and are arranged on different sides of the axis of rotation so that they act to rotate the blade holder in different directions. The hoses 6 and 7 are carried between the body 5 of the frame and the surface of the matching blade holder.

  It should be noted that there are many different structural styles of known blade holders on the market. The invention is thus not limited to the blade holder shown by way of example.

  The actual doctor blade 8 is mounted on the side of the blade holder 1 facing the roll and is properly supported. The above attachment is a conventional manner supported by the loading plate 9 and the counter plate 10.

  The broken line in FIG. 1 shows a blade structure 11 according to the prior art. In practice, this broken line says that the doctor blade 11 is shorter than the blade according to the invention. Prior art blades are also linear structures.

  Instead of using a straight structure, the blade structure 8 according to the present invention is curved, indicating that it is a sturdy construction compared to a doctor blade according to the prior art. By obtaining a structure without refraction and essentially no deflection, the doctor blade of the present invention can be clearly longer than the blades of the prior art, compared to using a conventional doctor blade. Therefore, frequent replacement of the doctor blade is suppressed. There is a considerable reduction in manufacturing costs.

  In addition, the structure according to the present invention has another effect. That is, by bending the doctor blade 8 as shown in the figure and bending the doctor blade 8 slightly upward as indicated by reference numeral 12, the angle of the blade with respect to the surface 2 of the roll is changed over the entire period of use of the blade. Can maintain a substantially constant angle. In addition, this eliminates the need for a separate measuring instrument for adjusting the angle, and thus has an effect of cost reduction. Similarly, since the angle, the contact surface, and the blade pressure do not change, the state of removal of unwanted objects by the doctor is kept constant throughout the period of operation of the doctor.

A protective plate suitable for the purposes of the present invention can be attached to the back of the blade so that dust that accumulates behind the blade does not enter the blade holder. An example of such a protective plate is shown in FIG. In particular, in a holder having a hose, it is a very important factor to prevent dust. If solid dust enters between the loading hose and the loading plate, the loading profile of the blade is biased.
This causes unevenness in blade wear, reduces the effect of removing deposits by the doctor, introduces dust into the paper, and deteriorates the moisture retention characteristics of the paper. The winding paper is damaged, and the production efficiency of the paper manufacturing equipment is reduced.

  As described above, the use of a structure that minimizes the negative effects on the manufacturing improves the doctor blade according to the present invention by a considerable reduction in manufacturing costs. The increased production of the blades of the present invention results in very low production costs.

  Although the present invention has been described with one specific example which is the best mode, the present invention is not limited thereto.

  Therefore, the blade according to the present invention shown in the figure can be applied in various ways. For example, instead of making the entire length of the blade a curved line, a curved part and a straight part may be connected. Further, the blade may be configured by respective curves having two directions. The radius of the curve can be changed according to the length of the blade. It is also practical to vary the thickness of the blade. A modification in which the thickness of the blade is reduced toward the blade tip position is particularly suitable.

  As indicated above, the blades are usually made of a composite material, in other words, usually formed of a plastic material with added reinforcement. The reinforcing material is an aramid fiber, carbon fiber, kevlar, or similar standard fiber material. Further, in the present invention, desired elastic characteristics and rigidity can be obtained by changing the amount of the reinforcing material and the fiber orientation. In other words, it is necessary to place more fibers in some parts than other parts of the blade, and also by placing the fibers in one direction or the other direction with respect to a specific part of the blade. Depending on the characteristics, the characteristics can be changed.

  It is even possible to change the shape and structure of the blade holder shown in the figure by way of example more greatly than the structure shown. The invention is in no way limited to the solution described. It is also self-evident that the pressure by the blades on the roll to remove unwanted material can be generated in any way. There is no need to couple the means for generating the pressure to the blade holder. For example, the pressure can be adjusted by a microprocessor and can be varied over the entire operating period.

1 shows a blade carrier, blade holder, and blade according to the present invention in a full size with no wear on the blade. The structure is the same as in FIG. 1 and shows a state where the blade is worn to some extent until the blade needs to be replaced.

Claims (8)

An elastic doctor, specifically aimed at removing unwanted material on the roll during the operation of the roll (2) of the paper making machine,
A blade (8) essentially having a width of the roll (2) from which unwanted material is removed and attached to the blade holder (1);
In an elastic doctor having working means (for example 6, 7) that produce the desired pressure of the doctor blade against the roll,
The blade (8) is made of a composite material composed of a base material and a reinforcing material formed of a fibrous material, and further, in an operating state, has a convex shape toward the outside of the roll (2). An elastic doctor.   The elastic doctor according to claim 1, characterized in that the blade holder (1) is arranged with the shaft pin (4) as a central axis so as to be able to rotate at least in a finite range.   Elasticity according to claim 1, characterized in that the doctor blade (8) is provided with a plate-like dust prevention device (13), if necessary, at a distance from the blade tip position. Doctor.   The elastic doctor according to claim 1, characterized in that the blade (8) is bent (12), curved or otherwise similar in the immediate vicinity of the joining position with the blade holder.   The elastic doctor according to any one of the preceding claims, characterized in that the blade (8) is a combination of a curved part and an essentially straight part.   The elastic doctor according to any one of the preceding claims, characterized in that the thickness of the blade (8) varies over the entire length of the blade.   8. The elastic doctor according to claim 7, wherein the blade (8) has a thickness that decreases toward the blade tip position.   The elastic doctor according to claim 1, characterized in that the number of reinforcing fibers and the direction of the fibers to be a composite material of the blade (8) are changed in different parts of the blade.

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