WO2011136032A1

WO2011136032A1 - Airflow distribution method of single-chamber vacuum furnace

Info

Publication number: WO2011136032A1
Application number: PCT/JP2011/059283
Authority: WO
Inventors: 勝俣　和彦
Original assignee: 株式会社Ihi; 株式会社Ｉｈｉ機械システム
Priority date: 2010-04-27
Filing date: 2011-04-14
Publication date: 2011-11-03
Also published as: JP2011231969A

Abstract

The disclosed vacuum heat-treatment furnace (1), which is provided with an airflow-direction adjustment plate (50) that is provided at a predetermined angle in a manner so as to lead coolant gas circulating within the furnace into an insulated vessel (10) in which an object (W) to be processed is disposed, has a displacement driving device (60) that drives the displacement of the angle of the airflow-direction adjustment plate (50) on the basis of at least one value from among the flow sped and the density of the abovementioned coolant gas.

Description

Air volume distribution method for single chamber type vacuum furnace

The present invention relates to a heat treatment furnace.
The present invention claims priority based on Japanese Patent Application No. 2010-102142 filed in Japan on April 27, 2010, the contents of which are incorporated herein by reference.

When quenching is performed in a heat treatment furnace, the quality of the object to be processed depends on how the cooling gas is allowed to flow into the heat insulating chamber in which the object to be processed is arranged with the same degree of distribution. If the distribution amount of the cooling gas to the heat insulation chamber is biased, for example, defects such as poor quenching of the workpiece and SUS sensitization are caused.

Patent Document 1 listed below discloses a heat treatment furnace capable of cooling an object to be processed in a short time by introducing nitrogen gas into the furnace, circulating the nitrogen gas with a fan, and cooling the nitrogen gas with a cooler. Yes. This heat treatment furnace is provided with wind direction guide vanes fixed at a predetermined angle so as to guide the cooling gas with a similar distribution to the heat insulating chamber in which the object to be processed is arranged.

JP-A-5-230528

However, since the airflow guide vanes with the above configuration are fixed, the distribution amount of the cooling gas flowing into the heat insulation chamber is not changed when the cooling gas flow velocity or density is changed no matter how the angle is adjusted to an optimum angle. There is a problem of changing. That is, when the flow velocity or density of the cooling gas is changed, the scalar value (strength) of the flow of the cooling gas changes, so that the cooling gas whose flow direction has been changed by the wind direction guide vane is changed by the cooling gas in the main flow direction. The degree of obstruction changes. As a result, the cooling gas flows into the heat insulation chamber in an uneven distribution.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat treatment furnace capable of suppressing the uneven distribution of the cooling gas with respect to the heat insulation chamber.

In order to solve the above problems, the present invention employs the following technique. That is,
(1) The present invention is a heat treatment furnace provided with a wind direction adjusting plate provided at a predetermined angle so as to guide the cooling gas circulating in the furnace into a heat insulating chamber in which an object to be processed is arranged, and the flow rate of the cooling gas And a displacement drive device that drives the angle of the wind direction adjusting plate to be displaced based on at least one of the values of density.
For this reason, in the present invention, the angle of the wind direction adjusting plate is driven to be displaced in accordance with the change in the flow rate or density of the cooling gas. Thereby, the deviation of the distribution amount of the cooling gas with respect to the heat insulation chamber due to the change in the flow velocity and density of the cooling gas is reduced.

(2) In the heat treatment furnace described in (1) above, the displacement driving device may drive the angle of the wind direction adjusting plate to be displaced based on both values of the flow velocity and density of the cooling gas.
For this reason, in the present invention, the angle of the wind direction adjusting plate is driven to be displaced in accordance with changes in the flow rate and density of the cooling gas. Thereby, the deviation of the distribution amount of the cooling gas with respect to the heat insulation chamber due to the change in the flow velocity and density of the cooling gas is reduced.

(3) In the heat treatment furnace described in (1) or (2) above, the displacement driving device is based on the number of rotations of the fan that circulates the cooling gas when using the flow velocity value of the cooling gas. The angle of the wind direction adjusting plate may be driven to be displaced.
For this reason, in this invention, it becomes possible to obtain | require the value of the flow velocity of cooling gas, without providing a flowmeter in a furnace.

(4) In the heat treatment furnace described in (1) to (3) above, the heat insulation chamber includes a cooling gas inlet opening in a vertical direction, and the wind direction adjusting plate is upstream of the cooling gas inlet. The first wind direction adjusting plate provided on the side and driven to move around the axis extending in the horizontal direction perpendicular to the flow direction of the cooling gas, and driven to move around the axis extending in the vertical direction perpendicular to the horizontal direction. You may have a 2nd wind direction adjustment board.
For this reason, in this invention, the adjustment | control of the flow of the cooling gas of a perpendicular direction and a horizontal direction is attained with respect to the cooling gas inflow port of a heat insulation chamber.

(5) In the heat treatment furnace described in (4) above, the second wind direction adjusting plate may be provided as a pair on both sides in the horizontal direction of the first wind direction adjusting plate.
For this reason, in the present invention, it is possible to adjust the flow of the cooling gas on both sides in the horizontal direction with respect to the cooling gas inlet of the heat insulating chamber.

The heat treatment furnace of the present invention includes a wind direction adjusting plate provided at a predetermined angle so as to guide the cooling gas circulating in the furnace into the heat insulating chamber in which the workpiece is disposed, and at least one of the flow velocity and density of the cooling gas. Based on one of the values, a displacement driving device that drives the displacement of the angle of the wind direction adjusting plate is provided. Thereby, the angle of the wind direction adjusting plate is driven to be displaced in accordance with the change in the flow rate or density of the cooling gas. Therefore, it is possible to reduce, that is, control the bias of the distribution amount of the cooling gas with respect to the heat insulating chamber due to the change in the flow velocity and density of the cooling gas.

It is a block diagram which shows the vacuum heat processing furnace in embodiment of this invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. It is a side view which shows the 1st wind direction adjustment board in embodiment of this invention. It is a top view which shows the 2nd wind direction adjustment board in embodiment of this invention. It is a figure for demonstrating the flow of the cooling gas in the vacuum heat processing furnace in embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, a vacuum heat treatment furnace will be described as an example of the heat treatment furnace of the present embodiment.

FIG. 1 is a configuration diagram showing a vacuum heat treatment furnace 1 in an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA in FIG. FIG. 3 is a side view showing the first air direction adjusting plate 51 in the embodiment of the present invention. FIG. 4 is a plan view showing the second air direction adjusting plate 52 in the embodiment of the present invention.
The vacuum heat treatment furnace 1 of the present embodiment is a so-called single-chamber vacuum heat treatment furnace that performs heat treatment and cooling treatment on the workpiece W in a single chamber. The vacuum heat treatment furnace 1 includes a vacuum pump (not shown) for sucking the inside of the furnace through a pipe 2 shown in FIG. 2, an inert gas supply device 3 for supplying an inert gas into the furnace shown in FIG. Have The inert gas is supplied into the furnace in order to prevent oxidation and coloring of the workpiece W, and is also used as a cooling gas for cooling the inside of the furnace. As the kind of the inert gas, for example, nitrogen gas, argon gas, helium gas, or a mixed gas of these inert gases is used. The inert gas supply device 3 includes a pumping unit that pumps the inert gas into the furnace and a measuring unit that measures the pressure in the furnace.

The vacuum heat treatment furnace 1 of the present embodiment is composed of a vacuum vessel which is set in a substantially cylindrical shape so as to withstand the pressure even when the pressure state in the furnace changes, and the cylindrical center of this vessel The position of the container is set so that the axis is horizontal. In the following description, the horizontal direction in which the central axis of the vacuum heat treatment furnace 1 extends is the X axis direction, the horizontal direction orthogonal to the X axis direction is the Y axis direction, and the vertical direction is orthogonal to the X axis direction and the Y axis direction. May be referred to as the Z-axis direction.
The vacuum heat treatment furnace 1 includes a heat insulating container (heat insulating chamber) 10 in which a workpiece W is disposed, a heating device 20 that heats the workpiece W, and a cooling device 30 that cools the workpiece W. Have

One end of the vacuum heat treatment furnace 1 is a clutch door 4. Note that the inner side of the clutch door 4 and the removable side wall 11 of the heat insulating container 10 are connected to each other, and the side wall 11 is detached by opening the clutch door 4, and the heat insulating container 10 is placed inside the heat insulating container 10. It is possible to carry in the workpiece W or carry out the workpiece W from the inside of the heat insulating container 10. Further, when the clutch door 4 is closed, the inside of the vacuum heat treatment furnace 1 is a sealed space. As shown in FIG. 2, in the furnace of the vacuum heat treatment furnace 1, the external space of the heat insulating container 10 is divided into two vertically by sandwiching the position where the heat insulating container 10 is provided by the partition plate 5 a and the partition plate 5 b.

In the heat insulating container 10, the workpiece W is heated and cooled. The heat insulating container 10 is made of a wool-based heat insulating material such as graphite wool or ceramic wool. The upper lid portion 12 constituting a part of the upper surface of the heat insulating container 10 can move in the vertical direction (Z-axis direction) by the cylinder mechanism 12 a and can open and close the opening 13 provided on the upper surface of the heat insulating container 10. Moreover, the lower lid part 14 which comprises a part of lower surface of the heat insulation container 10 moves to a perpendicular direction (Z-axis direction) by the cylinder mechanism 14a, and can open and close the opening part 15 provided in the lower surface of the heat insulation container 10. It is. A placing table 16 for placing the object to be processed W is disposed inside the heat insulating container 10. In order to prevent fusion with the object to be treated W on the placing table 16, the ceramic bar 17. Are installed. The mounting table 16 has a structure that allows gas to pass in the vertical direction (for example, a parallel plate extending in the X direction).

The heating device 20 has a grid-like heat generating portion that is provided in the heat insulating container 10 and surrounds the workpiece W. The heating device 20 heats the inside of the heat insulating container 10 to a high temperature of 1000 ° C. or more by heating the heat generating portion by energization in a state where the upper lid portion 12 and the lower lid portion 14 are closed.

The cooling device 30 includes a blower 31 and a heat exchanger 32. The blower 31 includes a fan 31a for circulating cooling gas (inert gas) in the furnace and a fan motor 31b for driving the fan 31a. The blower 31 rotates the fan 31a around the rotation axis extending in the X-axis direction, thereby sucking the cooling gas from the X-axis direction and ejecting the cooling gas in the radial direction, thereby giving a flow to the cooling gas. The cooling gas ejected from the fan 31a is a swirling flow around the X axis.

The heat exchanger 32 is composed of a plurality of fin tubes through which a cooling medium flows, and cools the cooling gas heated by cooling the workpiece W again. The heat exchanger 32 is provided so as to surround the radial direction of the fan 31a. The cooling device 30 cools the workpiece W by driving the blower 31 and the heat exchanger 32 and circulating the cooling gas in the furnace in a state where the upper lid portion 12 and the lower lid portion 14 are opened.

Also, the vacuum heat treatment furnace 1 of the present embodiment is provided with a circulation direction switching plate 40 for changing the circulation direction of the cooling gas. It is possible to change the circulation direction of the cooling gas inside the vacuum heat treatment furnace 1 by closing a suitable place in the internal space of the vacuum heat treatment furnace 1 with this circulation direction switching plate 40 and opening the suitable place. In the present embodiment, the circulation direction switching plate 40 causes the first cooling gas circulation direction in which the cooling gas flows from the top to the bottom in the heat insulation container 10 and the first cooling gas to flow in the heat insulation container 10 from the bottom to the top. It is possible to switch between two cooling gas circulation directions. That is, in the first cooling gas circulation direction, the opening 13 is a cooling gas inlet and the opening 15 is a cooling gas outlet. In the second cooling gas circulation direction, the opening 15 is opened at the cooling gas inlet. Part 13 is a cooling gas outlet.

The vacuum heat treatment furnace 1 of the present embodiment includes a wind direction adjusting plate 50 provided at a predetermined angle so as to guide the cooling gas circulating in the furnace into the heat insulating container 10 where the workpiece W is disposed, And a displacement driving device 60 for driving the angle of the airflow direction adjusting plate 50 based on at least one of the flow velocity and the density. In FIG. 1 and FIG. 2, an arrow output from the displacement driving device 60 indicates a path of electrical control by the displacement driving device 60. This electrical control is performed via a cable extending from the displacement driving device 60 so as to surround the vacuum heat treatment furnace 1. Arrows indicated by a 1, a 2, and a 3 output from the displacement driving device 60 indicate cable paths extending from the displacement driving device 60 to the lower portion of the vacuum heat treatment furnace 1. In the paths a1, a2, and a3, portions that are wired so as to surround the vacuum heat treatment furnace 1 are omitted, and only a connection portion between the displacement driving device 60 and the vacuum heat treatment furnace 1 is shown.
The wind direction adjusting plate 50 includes a wind direction adjusting plate 50A provided upstream of the opening 13 of the heat insulating container 10 in the first cooling gas circulation direction, and the opening 15 of the heat insulating container 10 in the second cooling gas circulation direction. A wind direction adjusting plate 50B provided on the upstream side. Since the configuration of the wind direction adjusting plate 50A and the wind direction adjusting plate 50B is substantially the same, in the following description, the configuration of the wind direction adjusting plate 50A will be described as the wind direction adjusting plate 50, and the configuration of the wind direction adjusting plate 50B will be described. Is omitted.

The wind direction adjusting plate 50 A is provided at a position avoiding the movement path of the upper lid 12. The wind direction adjusting plate 50A includes a first wind direction adjusting plate 51 that can be driven to be displaced around an axis extending in the Y-axis direction, and a second wind direction adjusting plate 52 that can be driven to be displaced about an axis extending in the Z-axis direction (FIG. 3). And FIG. 4). The first air direction adjusting plate 51 adjusts the flow direction of the cooling gas in the Z-axis direction.
The second air direction adjusting plate 52 adjusts the flow direction of the cooling gas in the Y-axis direction (particularly, adjusting the swirling flow (oblique flow) of the cooling gas around the X-axis).

The first wind direction adjusting plate 51 has substantially the same length as one side of the opening 13 in the Y-axis direction. The first wind direction adjusting plate 51 is pivotally supported by a rotating shaft 51a extending in the Y-axis direction on one side of the −X side (the side opposite to the arrow X in FIG. 1). A slide block 53 b to which the tip end portion 53 a of the cylinder mechanism 53 is fitted is fixed to the center portion of the first air direction adjusting plate 51. The slide block 53b is provided with a slide groove 53b1 extending along the surface of the first air direction adjusting plate 51. The cylinder mechanism 53 moves the tip portion 53a in the Z-axis direction under the control of the displacement drive device 60, thereby changing the fitting position of the slide block 53b with respect to the tip portion 53a, and the angle of the first wind direction adjusting plate 51 Is displaced around the rotation axis 51a.

The second wind direction adjusting plate 52 (52A, 52B) is provided as a pair on both sides of the first wind direction adjusting plate 51 in the Y-axis direction, as shown in FIG. That is, the distance between the second wind direction adjusting plate 52A and the second wind direction adjusting plate 52B is wider than the length of one side of the opening 13 in the Y-axis direction. The second wind direction adjusting plate 52 is pivotally supported as a rotation shaft 52a on one side extending in the Z-axis direction on the -X side. The rotating shaft 52a is driven under the control of the displacement driving device 60, and the angle of the second wind direction adjusting plate 52 is displaced around the rotating shaft 52a.

Returning to FIG. 1, the displacement driving device 60 drives the angle of the wind direction adjusting plate 50 A to be displaced based on at least one of the flow velocity and density of the cooling gas. The displacement driving device 60 of the present embodiment has a computer system that controls the displacement driving of the first wind direction adjusting plate 51 and the second wind direction adjusting plate 52, respectively.
Further, the displacement driving device 60 of the present embodiment uses the rotation speed of the fan 31a of the blower 31 as the value of the flow rate of the cooling gas, and specifically detects it by an encoder (not shown) provided in the fan motor 31b. The rotational speed data is taken into an inverter (not shown) that controls the driving of the fan motor 31b, and is output from the inverter and received. Further, the displacement drive device 60 of the present embodiment uses the pressure value in the furnace as the value of the density of the cooling gas, specifically, detected by the pressure measuring means (pressure sensor) of the inert gas supply device 3. Receive pressure data.

The displacement driving device 60 controls the displacement of the distribution amount of the cooling gas flowing into the heat insulating container 10 by driving the angle of the airflow direction adjusting plate 50A according to the flow velocity and density values of the cooling gas. When the flow velocity or density of the cooling gas is changed, the scalar value (strength) of the flow of the cooling gas changes, and the cooling gas whose flow direction is changed by the wind direction adjusting plate 50A is hindered by the cooling gas in the main flow direction. The degree changes. For this reason, the displacement drive device 60 drives the angle of the wind direction adjusting plate 50A to displace this change. Specifically, when the scalar value of the flow of the cooling gas is high (for example, when the flow velocity is large and the density is large), the displacement driving device 60 makes the angle of the first wind direction adjusting plate 51 shallow with respect to the XY plane, and the second wind direction. The angle of the adjustment plate 52 is controlled to be shallow with respect to the XZ plane.
On the other hand, when the scalar value of the flow of the cooling gas is low (for example, when the flow velocity is low and the density is low), the angle of the first air direction adjusting plate 51 is deep with respect to the XY plane and the angle of the second air direction adjusting plate 52 is XZ. Deep control over the plane.

Next, the operation of the vacuum heat treatment furnace 1 of the present embodiment configured as described above will be described with reference to FIGS.
FIG. 5 is a view for explaining the flow of the cooling gas in the vacuum heat treatment furnace 1 in the embodiment of the present invention. In FIG. 5, the flow of the cooling gas in the furnace is schematically shown by using arrows.

First, the workpiece W is carried into the heat insulating container 10 with the clutch door 4 of the vacuum heat treatment furnace 1 and the side wall 11 of the heat insulating container 10 opened. Thereafter, the clutch door 4 and the side wall 11 of the heat insulating container 10 are closed, and the upper lid 12 and the lower lid 14 are closed.
And the to-be-processed object W is heat-processed by heating the to-be-processed object W with the heating apparatus 20. FIG. In this heat treatment, the workpiece W is heated to a predetermined temperature over a predetermined time.

When such a heat treatment is completed, the cooling gas inlet / outlet (opening 13 and opening 15) of the heat insulating container 10 is opened by opening the upper lid 12 and the lower lid 14.
At the same time, the heat exchanger 32 cools the cooling gas, and the blower 31 applies a flow to the cooling gas, whereby the cooling gas circulates inside the vacuum heat treatment furnace 1. When the cooling gas circulated in this way is circulated in the direction of the arrow shown in FIG. 5, for example, after being discharged from the fan 31a, the flow direction is adjusted by the air direction adjusting plate 50A and then the opening 13 is formed. Flows into the inside of the heat insulating container 10.

Here, in the vacuum heat treatment furnace 1 of the present embodiment, the displacement driving device 60 drives the angle of the wind direction adjusting plate 50 A to be displaced according to the flow velocity and density values of the cooling gas, and flows into the heat insulating container 10. The flow rate and density of the cooling gas are controlled so as to eliminate the uneven distribution amount. Specifically, the first air direction adjusting plate 51 adjusts the flow direction of the cooling gas in the Z-axis direction, and introduces the cooling gas to the heat insulating container 10 with equal distribution. Further, the second air direction adjusting plate 52 adjusts the flow direction of the cooling gas in the Y-axis direction so as to cancel the swirling flow (diagonal flow) of the cooling gas around the X-axis so as to be equally distributed to the heat insulating container 10. Introduce cooling gas. For this reason, a cooling gas is sprayed uniformly with respect to the whole workpiece W, and the workpiece W can be cooled uniformly. Further, even if the rotational speed of the fan 31a and the pressure value in the furnace are changed during the cooling process, the displacement driving device 60 drives the angle of the airflow direction adjusting plate 50A to an optimum angle accordingly, The cooling gas can be always introduced to the heat insulating container 10 with equal distribution.

The cooling gas flowing into the heat insulating container 10 cools the workpiece W and then flows out of the heat insulating container 10 through the opening 15.
Thereafter, the cooling gas that has flowed out of the heat insulating container 10 is sucked by the fan 31a, is then heat-exchanged by the heat exchanger 32, and is circulated through the furnace again.

In the case where the circulation direction of the cooling gas is changed in the reverse direction by the circulation direction switching plate 40, the cooling gas is discharged from the fan 31a, and then the flow direction is adjusted by the air direction adjusting plate 50B and then the heat insulating container. 10 flows into the interior. Then, after cooling the workpiece W, the cooling gas flows out of the heat insulating container 10 through the opening 13. At this time, the displacement driving device 60 drives the angle of the airflow direction adjusting plate 50B in accordance with the values of the flow velocity and density of the cooling gas so as to eliminate the uneven distribution of the cooling gas flowing into the heat insulating container 10. Control the flow rate and density of the cooling gas.

When the cooling process of the workpiece W is completed in this way, the clutch door 4 of the vacuum heat treatment furnace 1 and the side wall portion 11 of the heat insulating container 10 are opened, and the workpiece W disposed inside the heat insulating container 10 is opened. Is carried out of the heat insulating container 10.

Therefore, according to this embodiment described above, the airflow direction adjusting plate 50 provided in the vacuum heat treatment furnace 1 is predetermined so as to guide the cooling gas circulating in the furnace into the heat insulating container 10 in which the workpiece W is disposed. It is set to an angle. Further, the displacement driving device 60 drives the angle of the wind direction adjusting plate 50 to be displaced based on at least one of the flow velocity and density of the cooling gas. For this reason, in this embodiment, the angle of the wind direction adjusting plate 50 is driven to change according to the change in the flow rate and density of the cooling gas, and the distribution amount of the cooling gas to the heat insulating container 10 by the change in the flow rate and density of the cooling gas The bias can be reduced, that is, controlled. Therefore, it is possible to suppress quenching failure of the workpiece W, SUS sensitization, and the like, and to obtain a high-quality workpiece W.

Note that the operation procedure shown in the above-described embodiment, or the shapes, materials, combinations, and the like of each component are examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention. is there.

For example, when the rotation direction of the fan 31a is only one, the swirling flow (diagonal flow) of the cooling gas around the X axis is biased only on one side, and therefore, on both sides of the first air direction adjusting plate 51 in the above embodiment. The second air direction adjusting plate 52 provided as a pair may be provided only on one side of the first air direction adjusting plate 51.
Further, for example, the displacement driving device 60 may simultaneously perform the displacement driving of the angle of the airflow direction adjusting plate 50A and the displacement driving of the angle of the airflow direction adjusting plate 50B. By simultaneously executing the displacement drive, even when the circulation direction switching plate 40 changes the circulation direction of the cooling gas in the reverse direction, the displacement drive can be handled instantaneously.

DESCRIPTION OF SYMBOLS 1 ... Vacuum heat treatment furnace (heat treatment furnace), 10 ... Heat insulation chamber (heat insulation container), 13 ... Opening part (cooling gas inflow port), 31a ... Fan, 50 ... Wind direction adjusting plate, 51 ... 1st wind direction adjusting plate, 52 ... Second wind direction adjusting plate, 60 ... displacement driving device, W ... workpiece

Claims

A heat treatment furnace provided with a wind direction adjusting plate provided at a predetermined angle so as to guide a cooling gas circulating in the furnace into a heat insulating chamber in which an object to be processed is arranged,
A heat treatment furnace having a displacement driving device for driving the angle of the wind direction adjusting plate to be displaced based on at least one of the flow velocity and density of the cooling gas.
The heat treatment furnace according to claim 1, wherein the displacement driving device drives the angle of the wind direction adjusting plate to be displaced based on both values of a flow rate and a density of the cooling gas.
3. The displacement driving device according to claim 1, wherein, when the value of the flow rate of the cooling gas is used, the displacement driving device drives the angle of the wind direction adjusting plate to be displaced based on the number of rotations of a fan that circulates the cooling gas. Heat treatment furnace.
The heat insulation chamber includes a cooling gas inlet opening in a vertical direction,
The wind direction adjusting plate is provided on the upstream side of the cooling gas inflow port, and the first wind direction adjusting plate is driven to move around an axis extending in a horizontal direction orthogonal to the flow direction of the cooling gas, and the horizontal direction The heat treatment furnace according to any one of claims 1 to 3, further comprising a second wind direction adjusting plate that is driven to move around an axis extending in a vertical direction perpendicular to the vertical direction.
The heat treatment furnace according to claim 4, wherein the second wind direction adjusting plate is provided as a pair on both sides in the horizontal direction of the first wind direction adjusting plate.