JP2000213652A - Shaft seal structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft seal structure free to easily assemble and disassemble in simple structure. SOLUTION: A bearing 6 on an inner surface of which a peripheral groove 6a is formed is internally fited at a position on the side of a frame body 1 of a hollow cylindrical stuffing box 5 installed on the outside of the frame body 1 so as to surround a damper shaft 4 projected from the frame body 1 of closed structure in such a way as to pivotally support the damper shaft 4, a plural number of grand packings 9 externally fitted on the damper shaft 4 are installed on the side of an anti-frame body 1 of the bearing 6 in the stuffing box 5, a packing presser 11 capable of pressurizing the grand packing 9 is installed on an end part of the stuffing box 5, and seal air 14 is supplied to a peripheral groove 6a of the bearing 6 through a seal air supply port 13 from outside of the stuffing box 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft seal structure.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show an example of a damper used in a flue of a boiler or the like. The damper is provided with a frame 1 having a closed structure and substantially inside the frame 1. The flue is closed by pivoting and pivoting to extend horizontally.
A plurality of vanes 2 juxtaposed so as to be openable, a link 3 for connecting the tip of a lever 2a extending radially from the center of rotation of each vane 2 blade tip, and a link 3 directly connected to one vane 2; And a damper shaft 4 protruding to the outside of the frame 1. The plurality of vanes 2 are synchronized by rotating the damper shaft 4 by the operation of a driving device (not shown). It is designed to rotate.

[0003] The projecting end of the damper shaft 4 is pivotally supported by a bearing 6 provided in a staffin box 5 described later.

FIG. 4 shows an example of the stuffing box 5. The stuffing box 5 has a hollow cylindrical box body 8 whose base is attached to the outside of the frame 1 via a flange 7, 8 and the damper shaft 4
A plurality of gland packings 9 formed of glass fiber or the like fitted to the outside, a spacer 10 disposed between the gland packings 9, and a gland packing 9 inserted from the open end side of the box body 8. And a hollow cylindrical packing presser 11 formed so as to press the spacer 10 and fit the metallic bearing 6 therein.

[0005] The spacer 10 has a ring shape loosely fitted to the damper shaft 4 and has a circumferential groove 12 extending circumferentially along the inner surface.
The seal air 14 is formed in the circumferential groove 12 so as to receive supply of the seal air 14 through a seal air supply port 13 provided in the box body 8. The gland packing 9 has a structure capable of preventing the gas inside the frame 1 from leaking outside from the through portion of the damper shaft 4.

[0006]

When the gland packing 9 in the stuffing box 5 shown in FIG. 4 is to be replaced, the damper shaft 4 is cut off from a driving device (not shown), and the packing presser 11 is removed. After the bearing 6 is pulled out of the box body 8 and the bearing 6 is separated from the damper shaft 4, the gland packing 9 and the spacer 10 are removed from the damper shaft 4.

However, since the exposed portion of the damper shaft 4 is usually applied with a paint such as a rust preventive, the bearing 6 is made of metal and hardly elastically deformed. , By the rust inhibitor,
The work of pulling out the bearing 6 is often hindered, and paint such as a rust preventive must be removed, which has the disadvantage that extra work and time are required.

Further, since the spacers 10 are arranged between the plurality of gland packings 9 and formed so as to supply the sealing air 14 to the spacers 10, the number of parts increases, the structure becomes complicated, Assembly work was also complicated.

Further, when the gland packing 9 shrinks and hardens due to heat and the gap between the gland packing 9 and the damper shaft 4 becomes large, the sealing air 14 supplied to the circumferential groove 12 of the spacer 10 is removed. The gap easily leaks to the outside through the gap between the box body 8 and the packing retainer 11 and the like, and a large amount of the seal air 14 is required.

The present invention has been made in view of the above circumstances, and the gland packing can be smoothly replaced without removing paint such as a rust preventive applied to the shaft. It is an object of the present invention to provide a shaft seal structure which can simplify the structure of the shaft seal and can further reduce the amount of seal air.

[0011]

SUMMARY OF THE INVENTION The present invention provides a hollow cylindrical stuffing box attached to the outside of a frame so as to surround a shaft protruding from the frame having a closed structure, and a frame in the stuffing box. A bearing having a circumferential groove which is fitted inside the body to pivotally support the shaft and extends circumferentially along the inner surface;
A seal air supply port formed so as to communicate with the circumferential groove of the bearing from the outside of the stuffing box; and a plurality of sealing air supply ports fitted to the shaft and mounted in the stuffing box so as to be adjacent to the opposite frame side of the bearing. A shaft seal structure comprising: a gland packing; and a hollow cylindrical packing holder fastened to an end of a stuffing box so as to press the gland packing.

According to the above means, the following effects can be obtained.

[0013] By installing the bearing in the box body of the stuffing box instead of assembling it in the packing retainer, it is possible to increase the gap between the packing retainer and the shaft. After removing the packing retainer from the box body of the stuffing box, it is possible to remove only the gland packing from the shaft without removing the bearing, and replace it. Need not be removed.

Further, the conventional spacer is not required.

Further, since the seal air is supplied to the circumferential groove formed in the bearing having a small gap with respect to the shaft, the gland packing temporarily contracts and hardens due to heat, so that the gland packing and the shaft are hardened. Even if the gap between them increases, the seal air supplied to the circumferential groove of the bearing has almost no effect, and the amount of the seal air can be reduced.

[0016]

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

FIG. 1 shows an example of an embodiment of a shaft seal structure of the present invention. In FIG. 1, the same reference numerals as in FIG. 4 denote the same parts.

The box body 8 of the stuffing box 5 has a small-diameter portion 8a through which the damper shaft 4 passes, a medium-diameter portion 8b in which the bearing 6 is fitted, and a large-diameter portion 8c to which the gland packing 9 is mounted. Are formed so as to be sequentially adjacent from the base on the side of the frame 1 toward the open end, and the stuffing box 5 is provided outside the frame 1 via the flange 7 on the small diameter portion 8a side of the box body 8. The damper shaft 4 penetrates the center of the small diameter portion 8a.

On the inner peripheral surface of the bearing 6, a circumferential groove 6a is formed so as to extend in the circumferential direction along the outer surface of the damper shaft 4, and a seal air supply bored in the box body 8 of the staffin box 5 is formed. A communication hole 6b for guiding the seal air 14 supplied to the port 13 to the circumferential groove 6a is formed at a required position in the circumferential direction of the bearing 6, and the bearing 6 is formed in the box body 8 of the staffin box 5. The damper shaft 4 is fitted inside the middle diameter portion 8b so as to pivot.

The gland packing 9 is fitted over the damper shaft 4 to be adjacent to the bearing 6 and a large-diameter portion 8 of the box body 8 of the stuffing box 5 so that a plurality of the packings are in close contact with each other.
c.

The packing retainer 11 presses the gland packing 9 against the bearing 6 to prevent the gland packing 9 from falling off.
A bolt is fastened to the flange 15 at the opening end of the box main body 8 of the stuffing box 5.

Reference numeral 16 denotes a bearing fixing bolt.

Next, the operation of the illustrated example will be described.

By mounting the bearing 6 in the box body 8 of the stuffing box 5 instead of assembling it in the packing holder 11, the dimension A of the gap between the packing holder 11 and the damper shaft 4 is increased to about 2 mm. When replacing the gland packing 9, the bolts are released and the packing retainer 11 is removed from the box body 8 of the stuffing box 5, and then the gland packing 9 is removed without removing the bearing 6. The damper shaft 4
It is possible to remove it and replace it.

Therefore, since it is not necessary to remove the bearing 6 when replacing the gland packing 9, the paint does not have to be removed from the damper shaft 4 to which a paint such as a rust preventive has been applied. Exchange can be easily performed.

Further, since the bearing 6 is provided with the circumferential groove 6a and the spacer 10 as shown in the conventional example of FIG. 4 is eliminated, the number of parts is reduced, the structure is simplified, and the assembling work is also facilitated.

Further, in the example shown in FIG. 1, since the seal air 14 is supplied to the circumferential groove 6a formed in the bearing 6 in which the clearance with the damper shaft 4 is kept small, the gland packing 9 is temporarily provided. Even if the gas shrinks and hardens due to the heat of the gas and the gap between the gland packing 9 and the damper shaft 4 increases, the seal air 14 supplied to the circumferential groove 6a of the bearing 6 has almost no effect. The amount of the seal air 14 can be reduced.

It should be noted that the shaft seal structure of the present invention is not limited to the above-described example, but may be applied to a seal structure of a shaft other than the damper shaft. Of course, various changes can be made within the range.

[0029]

As described above, according to the shaft seal structure of the present invention, since the bearing is arranged on the frame and the gland packing is fitted on the opposite side of the bearing, the gland packing can be replaced. Because the bearing does not need to be removed, the gland packing can be easily replaced even on a shaft coated with a paint such as a rust preventive. Therefore, the number of parts can be reduced, the structure can be simplified, the assembling work can be facilitated, and the amount of sealing air can be further reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of an embodiment of a shaft seal structure of the present invention.

FIG. 2 is a front view of an example of a conventional damper.

FIG. 3 is a view taken in the direction of arrows III-III in FIG. 2;

FIG. 4 is a cross-sectional view of an example of a conventional shaft seal structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 4 Damper shaft (shaft) 5 Stuffing box 6 Bearing 6a Peripheral groove 9 Gland packing 11 Packing press 13 Seal air supply port

Claims (1)

[Claims] 1. A hollow cylindrical stuffing box attached to the outside of a frame so as to surround a shaft protruding from the frame having a closed structure, and a shaft pivotally supported at a position on the frame side in the stuffing box. Bearing having a circumferential groove extending in the circumferential direction along the inner surface of the bearing, a seal air supply hole formed so as to communicate with the circumferential groove of the bearing from outside the stuffing box, and an outer fit on the shaft. A plurality of gland packings mounted in the stuffing box so as to be adjacent to the side opposite to the frame of the bearing, and a hollow cylindrical packing fastened to an end of the stuffing box so as to press the gland packings A shaft seal structure comprising a presser foot.