JPS6137397B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an over-drying prevention device for a drum dryer in a paper machine.

The drum dryer used in paper machines is
Generally, as shown in FIG. 1, heating is performed by supplying steam 3 through a steam supply path 2 into a drum 1 constituting a drum dryer, while wet paper 4 to be dried is heated around the outer circumference of the drum 1. Rather than contacting the drum over its entire length, it is usually
The contact is made in a position range excluding both ends 1' in the axial direction. However, such drum 1 is
Both ends 1' in the axial direction are subjected to less load due to contact with the wet paper 4, and therefore, during drying, the temperature at both ends 1' is higher than at the center of the drum, and both ends (edges) of the paper There was a problem with overdrying and not being able to dry uniformly. In the figure, reference numeral 5 indicates a siphon pipe provided in the center of the drum 1 for discharging condensed water generated within the drum 1, 6 a supporting leg of the siphon pipe 5, and 7 a manhole.

In recent years, in order to deal with the above-mentioned problem, insulation material a has been applied to both axial ends 1' of the inner wall of the drum 1 by lining, painting, or by bringing a block of material into the interior through the manhole 7 and assembling it. It has been considered to provide it in the circumferential direction to prevent the edges of the paper from overdrying. but,
Even in this method, due to the expansion and contraction caused by the difference in thermal expansion coefficient between the metal material constituting the drum 1 and the heat insulating material a, a gap is created between the heat insulating material a and the drum 1. As a result, the drum end 1' position where a gap has been generated becomes high temperature, making it impossible to dry uniformly. It is possible to provide a holding mechanism that presses the inner wall surface of both ends 1' with equal force, but this requires high manufacturing precision, and in particular, it is necessary to make small blocks because they are brought into the interior through the small manhole 7 and assembled. It is very difficult to assemble such a presser mechanism within the clamping drum 1 with high precision.

The present invention was made in view of these points.
A heat insulating space is formed on the inner circumferential surface of both ends of the drum by sandwiching both sides of the elastic mist trapping wire with a flexible sheet member that prevents direct heat transfer. By providing a heat insulator and a support device that presses and supports the heat insulator against the inner circumferential surface of the drum, the effect of preventing heat transfer to the drum in the heat insulating space is enhanced and overdrying of the width edge of the paper is prevented. In addition, the elastic mist trapping wire allows the heat insulator to be brought into close contact with the inner surface of the drum without requiring high precision from the support device. Also, when the mist trapping wire 10 is thick enough, the sheet member 12,
13 can also be made unnecessary.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an example of the present invention applied to the drum 1 shown in FIG. Press down and set.

The heat insulating body 9 includes a mist trapping wire 10 that has many spaces and is elastic, and the mist trapping wire 10 is supported on sand benches from both sides to form a heat insulating space 11. Teflon,
It is constructed in an annular shape by flexible sheet members 12 and 13 made of a resin sheet such as PEEK or a dense wire sheet (for example, 150 mesh or more). Further, the support device 8 is composed of an arc-shaped block, and after being carried into the drum 1 through the manhole 7, it is assembled into a ring shape to press and support the heat insulator 9 against the inner circumferential surface of the drum 1 with a required force. The drum 1 includes a support ring 14 and plate springs 16 and 17 which are fixed to the support ring 14 via bolts 15 to press the heat insulator 9 against the inner surface of the drum 1.

For assembly, a heat insulator 9 consisting of annularly formed sheet members 12, 13 and a mist trapping wire 10 is carried in from the manhole 7 shown in FIG. position it on the surface,
Further, the support ring 14 and the leaf springs 16 and 17, which have been made into blocks, are transported from the manhole 7 to the inner circumferential surface of the heat insulator 9, and the support device 8 is assembled.

As another embodiment, as shown in FIG.
6 and 17 may be placed under the support ring 14 to increase the heat insulation properties. FIG. 5 shows an example in which the heat insulating material and the support are integrated.

In this way, the heat insulator 9 is connected to the leaf springs 16, 1
7 against the inner circumferential surface of the drum 1, and since the insulating body 9 itself has elasticity as well as the mist trapping wire 10, the insulating body 9 is pressed against the inner circumferential surface of the drum 1 even if a thermal change occurs. It is pressed and supported with a substantially uniform force without separating from the object. Therefore, as shown in FIG. 3, the steam 3 that attempts to attack from directions A and B is blocked by the sheet member 12, and the steam that has passed through the sheet member 12 is also trapped by the mist that forms the heat insulating space 11. By turning it into a mist using the heating wire 10, the presence of the heat insulating space 11 provides appropriate heat insulation, suppressing heat transfer to the drum 1 side, and effectively preventing overdrying. Further, in the above, when the mist trapping wire 10 is sufficiently thick, the sheet members 12 and 13 may be unnecessary.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and that the heat insulating body may have a layered structure such as forming a plurality of layers of heat insulating spaces, and that various types of support devices other than those shown in the drawings may be adopted. Of course, the width dimension, arrangement position, etc. of the heat insulating body may be changed in various ways, and various other changes may be made without departing from the gist of the present invention.

According to the above-described over-drying prevention device for a drum dryer in a paper machine of the present invention, the following excellent effects can be achieved.

(i) By forming a heat insulating space inside the heat insulator using the mist trapping wire, it effectively prevents heat transfer to the drum in the area where the heat insulator is placed, improving the effect of preventing overdrying. I can do it.

(ii) By providing the elastic mist trapping wire, the heat insulator can be uniformly brought into close contact with the inner surface of the drum without requiring high precision from the support device.

(iii) Since high precision is not required for the heat insulator and the support device, it can be manufactured at low cost and is easy to assemble.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of the configuration of a general drum and a conventional method, Fig. 2 is a partially enlarged explanatory diagram showing an example of the present invention applied to the drum of Fig. 1, and Fig. 3 is an explanatory diagram showing an example of the present invention applied to the drum of Fig. 1. 4 and 5 are explanatory diagrams showing other embodiments of the present invention. 1 is a drum, 1' is both ends, 4 is a wet paper, 8 is a support device, 9 is a heat insulator, 10 is a mist trapping wire, 11 is a heat insulating space, and 12 and 13 are sheet members.

Claims (1)

[Claims] 1. A heat insulating body is provided on the inner circumferential surface of both axial ends of the dryer drum, and the heat insulating body is constructed by sandwiching both sides of an elastic mist trapping wire between airtight flexible sheet members. An over-drying prevention device for a drum dryer in a paper machine, characterized in that a support device for pressing and supporting the heat insulator against the inner circumferential surface of the dryer drum is provided on the inner side of the drum dryer.