JPH02175989A - Rotary drying drum - Google Patents

Abstract

PURPOSE:To collect the drain generated in a drum to an end part of the drum and remove the drain in high efficiency by forming a spiral rim on the inner circumference of a shell of a rotary hot drum or forming a spiral groove on the circumference. CONSTITUTION:A spiral rim 9 is formed on the inner circumference of a shell 2 of a rotary hot drum containing a shell 2 heated with steam introduced into the drum. As an alternative method, a spiral groove is formed on the inner circumference of the shell 2 of the drum, The drain generated in the drum is collected in high efficiency to an end of the drum according to the rotation of the drum. The collected drain is discharged from the drum by a siphon.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rotary drying drum used in paper machines and the like.

[Conventional technology] On a long belt-shaped paper screen running at high speed, paper stock (pulp is beaten and crushed into small pieces and liquefied) is dehydrated to form a paper layer, which is then compressed, A rotary drying drum is generally used in the drying process of paper machines that perform dewatering and drying to make paper.

FIG. 7 shows the above-mentioned rotary drying drum. As shown in the figure, the rotary drying drum 1 is mainly composed of a cylindrical shell 2 made of metal with high thermal conductivity, and its axis Cylindrical rotating shaft parts 3 and 4 arranged at both ends in the center direction
is supported in a drivable manner via one rotating shaft portion 3.
High temperature steam is introduced into the rotary drying drum 1 through the hollow part thereof to heat the shell 2, as shown in FIG.
As the process of wrapping the wet paper web 5 along the outer periphery of the shell 2 and sending out the wet paper paper 5 by rotating the rotary drying drum l by a drive device (not shown) is repeated using a plurality of rotary drying drums 1, There is a device for drying the wet paper 5.

In such a rotary drying drum 1, drain 6 accumulates when the shell 2 is heated and the cooled steam liquefies, so a siphon 7 is provided to pass through the other rotating shaft portion 4.
The siphon 7 is designed to suck in the drain 6 and discharge it to the outside.

However, since the rotary drying drum 1 is constantly rotating, a water film is formed by the drain 6 on the inner peripheral surface of the shell 2 due to centrifugal force, and not only is the drain 6 not efficiently discharged, but the drain 6 The water film inhibited heat conduction from the steam, resulting in a significant decrease in thermal conductivity.

Therefore, conventionally, a plurality of thermorims 8 for scraping water film are disposed on the inner peripheral surface of the shell 2 in parallel with the axis and at required intervals in the circumferential direction. drain 6
By stirring the water with each of the thermorims 8, formation of a water film on the inner circumferential surface of the shell 2 was prevented.

[Problems to be Solved by the Invention] However, if the drain 6 in the rotary drying drum 1 is simply stirred by the thermorim 8, the drain 6 on the inner circumferential surface of the shell 2 is not substantially eliminated and is removed from the steam. There was a problem that it was insufficient to significantly improve the thermal conductivity of the drain 6, and that it became increasingly difficult to discharge the drain 6 using the siphon 7.

The present invention solves the above-mentioned problems by attaching a thermorim in a spiral manner to the inner circumferential surface of the shell of a rotary drying drum, or by forming a spiral groove in the inner circumferential surface of the shell to siphon the drain. By providing a rotary drying drum in which the thickness of condensate formed on the inner peripheral surface of the shell is minimized by forcing it to the side and collecting it, and discharging it with a siphon, The purpose is to significantly improve thermal conductivity.

[Means for Solving the Problems] The present invention provides a rotary drying drum that introduces steam into the drum, heats it, and rotates the wet paper along the outer periphery of the drum to dry the wet paper. The rotary drying drum is characterized by having a plurality of thermorims arranged in a spiral shape on the inner circumferential surface of the drying drum to transform the condensate into a whirlpool. A rotary drying drum that dries wet paper by rotating it while making contact with the paper, characterized in that a plurality of spiral grooves are formed on the inner peripheral surface of the rotary drying drum to turn the drain into a whirlpool. It is attached to a rotating drying drum.

[Function] Therefore, when the rotary drying drum is rotated, the drain on the inner peripheral surface of the rotary drying drum is swept away in the axial direction of the rotary drying drum by the action of the spiral thermorim or groove.

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

In heat conduction from steam as shown in FIG. 9, a heat conduction equation is established for each of the drain and shell. In the above equation, the amount of heat, θd1 is the boundary temperature between steam and drain, θd2 is the boundary temperature between drain and shell, θ
S is wet paper temperature, td is drain thickness, ts is shell thickness,
λd indicates the thermal conductivity of the drain, and λS indicates the thermal conductivity of the shell.

By eliminating θd2 from the above two equations, we get the wet paper paper temperature θS and the boundary temperature between steam and drain θd
1 is constant, the heat ff1q is here, and considering the respective values in the actual machine, the thermal conductivity of the drain is λd -0,1kcal/m -h
r ・'C shell thermal conductivity λ5-40kcal/m
-hr ・'C drain thickness td -2~5■ Shell thickness ts - This is about 20me+.

That is, since λd changes somewhat depending on the temperature, it can be considered to be substantially constant, so it is considered that a change in td appears as a large change in the heat Qq.

Therefore, if the thickness of the drain (thickness of the water film of the drain) can be reduced, the amount of heat transmitted to the wet paper can be significantly increased, as shown by the dashed line in the figure.

1 and 2 illustrate one embodiment of the present invention, and FIG. 2 is illustrated using perspective for clarity. As shown in the figure, a cylindrical shell 2 made of a metal with high thermal conductivity is provided, and a plurality of thermorims 9 are arranged in a spiral shape on the inner peripheral surface of the shell 2, and screwed or pressed in a ring shape. Furthermore, drum lids 10 and 11 are arranged and closed at the openings at both ends in the axial direction of the shell 2, and a cylindrical rotating shaft is installed at the center of the drum lids 10 and 11. The shaft parts 3 and 4 are fitted together, and one rotating shaft part 3 has a steam inlet 12 that communicates with the inside of the shell 2 through the internal space, and the other rotating shaft part 4 has a steam inlet 12 that communicates with the inside of the shell 2 through the internal space. A siphon 7 bent toward the inner circumferential surface of the shell 2 is provided by fitting into the internal space of the rotating shaft portion 4, and both rotating shaft portions 3
and 4 are each supported by a drive device (not shown) to constitute the rotary drying drum 13 of the present invention.

The action will be explained below.

The rotary drying drum 13 is driven by a drive device (not shown).
While rotating and driving, high-temperature steam is supplied from the steam inlet 12 into the rotary drying drum 13 to heat the shell 2, and the shell 2 is used to dry and send out wet paper (not shown). Then, as described above, steam that is cooled and liquefied by transferring heat to the shell 2 accumulates in the rotary drying drum 13 as a drain 6.

At this time, the drain 6 is pushed toward one end of the rotary drying drum 13 in the axial direction (siphon 7 side) by the thermorim 9 arranged in a spiral manner on the inner peripheral surface of the shell 2.

Here, it goes without saying that the direction of inclination of the thermorim 9 or the direction of rotation of the rotary drying drum 13 is set in advance so that the train 6 is swept toward the side where the siphon 7 is disposed.

Therefore, according to the above, the drain 6 stored on the inner circumferential surface of the shell 2 and the lower end of the shell 2 has a spiral thermorim 9.
The thickness of the drain 6 that remains on the inner peripheral surface of the shell 2 due to the centrifugal force becomes much thinner than before, and the amount of heat transmitted to the wet paper increases significantly as described above. The thermal conductivity of the rotary drying drum 13 can be significantly improved.

Furthermore, as shown in FIG. 3 or 4, if the water inlet 14 of the siphon 7 is formed to face the flow direction of the drain 6 and open at a wide angle, the flow of the drain 6 by the thermorim 9 can be reduced. It is also possible to use this method to recover the drain 6 more efficiently.

In the above embodiment, the steam inlet 12 may be arranged on either side in the axial direction, and may be arranged alternately on the opposite side from other adjacent rotary drying drums. do,
Of course, it is necessary to ensure uniform drying of the wet paper.

FIG. 5 shows an external appearance of a modification of the above embodiment, in which the inclination direction of the thermorim 9° is reversed from the center, and the siphons 7 are also provided on both sides in the axial direction. . In this case, due to the shape of the spiral thermorim 9', the drain 6 is swept away to both sides in the axial direction of the drum, so the thermal conductivity of the rotary drying drum 13 can be significantly improved. Non-uniform heating of the shell 2 in the drying drum 13 due to the influence of the drain 6 can be suppressed.

FIG. 6 shows another embodiment of the invention (the drawing is shown in perspective for clarity), in which instead of arranging the thermorim 9 in a spiral shape, the shell 2
It has a configuration in which a spiral groove 15 is provided on the inner peripheral surface.

In this case, as described above, when the rotary drying drum 13 is rotated, the drain 6 can be swept away in the axial direction of the drum by the spiral grooves 15 formed inside the drum, so that the thermal conductivity can be significantly improved. .

Further, the shape of the groove 15 is as shown in the modified example shown in FIG.
The thickness of the drain 6 can also be effectively reduced by forming the groove 15' with an inverted shape from the center.
In addition, uneven heating of the shell 2 due to the influence of the drain 6 in one rotary drying drum I3 can be suppressed.

It should be noted that the rotary drying drum of the present invention is not limited to the above-described embodiments, but can also be applied to a system in which the siphon is integrally attached to the rotary drying drum, which departs from the gist of the invention. Of course, various changes can be made within the scope.

[Effects of the Invention] As explained above, according to the rotary drying drum of the present invention, the drain on the inner peripheral surface of the rotary drying drum can be swept away in the axial direction of the drum, thereby applying centrifugal force to the inner peripheral surface. As a result, the thickness of the retained condensate can be made much thinner than in the past, and the excellent effect of significantly improving the thermal conductivity for transmitting the amount of heat from the steam to the wet paper can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a front view of one embodiment of the present invention, Fig. 2 is a sectional view taken from the direction ■-■ in Fig. 1 with a sense of perspective, and Fig. 3 is a view of a shell showing an example of a siphon. 4 is an enlarged perspective view of the siphon, FIG. 5 is a front view showing a modification of the present invention, and FIG. 6 is a diagram showing another embodiment of the present invention as shown in FIG. A cross-sectional view with perspective from the ■−■ direction of
FIG. 7 is a front view showing an example of a conventional example, FIG. 8 is a perspective view showing a simplified wet paper drying process, and FIG. 9 is an explanatory diagram showing a graph of heat conduction of steam heat. In the figure, 6 is a drain, 9.9' is a thermorim, 12 is a steam inlet, 13 is a rotary drying drum, and 15.15' is a groove.

Claims (1)

[Claims] 1) A rotary drying drum that introduces steam into the drum, heats it, and rotates the wet paper along the outer periphery of the drum to dry the wet paper. On the inner surface,
A rotary drying drum characterized by a plurality of spirally arranged thermorims that turn the drain into a whirlpool. 2) In a rotary drying drum that introduces steam into the interior and heats it, and rotates and dries the wet paper while contacting the wet paper along its outer periphery, on the inner circumferential surface of the rotary drying drum,
A rotary drying drum characterized by a plurality of spiral grooves that turn the drain into a whirlpool.