JPH0214701Y2 - - Google Patents

Description

[Detailed description of the invention] (1) Industrial application field This invention relates to a shaft sealing device for a butterfly valve.

(2) Prior Art As this type of shaft sealing device, the one shown in FIG. 6 is known. In Fig. 6, 51 is a valve seat 52 on the inner periphery.
53 is a valve body having a valve seat 54 in sliding contact with the valve seat 52 on its outer periphery; 55 is a sealing member;
Reference numeral 56 denotes a presser cylinder, which is fitted into the bearing portion 57 of the valve case 51 so as to seal around the valve shaft 58.

(3) Problems to be solved by the invention By the way, the sealing member 55 is not connected to the valve body valve seat 54.
Although the valve body side end face is brought into sliding contact with the valve body to prevent liquid from leaking to the valve shaft 58, the valve body side end face gradually wears out due to sliding as the valve body 53 opens and closes. , a gap was created between the valve body and the sliding surface of the valve seat 54. Therefore, there was a problem in that the liquid passing through the pipe line entered the gap and corroded the valve shaft 58. Therefore, in this invention, even if the end surface of the sealing member 55 on the valve body side is worn out and a gap is created between the valve body and the sliding surface of the valve seat 54, liquid will not infiltrate into the valve shaft through the gap. The technical challenge is to be able to prevent this.

(4) Means for solving the problem A circular recess is provided in a part of the sliding contact surface of the valve body valve seat that comes into sliding contact with the first sealing member on the valve shaft side, and the first seal member is placed in the circular recess. A hollow annular second seal member having a generally U-shaped cross section and having one side piece that faces the seal member, the other side piece that faces the bottom surface of the circular recess, and a connecting piece that connects the both side pieces on the valve shaft side. The connecting piece is fitted and housed in the valve stem, and when it comes into contact with liquid, the connecting piece swells and increases in volume, expanding the second sealing member and forming one side piece into the first sealing member. The member accommodates an annular swelling member that brings the other side piece into close contact with the bottom surface of the circular recess.

(5) Effect When the end face of the first seal member on the valve body side wears out, a gap is created between the valve body and the sliding surface of the valve seat, and when liquid enters through the gap, the swelling member swells with this liquid. The volume increases and fills the circular recess. As a result, one side piece of the second seal member comes into close contact with the first seal member, and the other side piece comes into close contact with the bottom surface of the circular recess, so that the liquid that has entered is sealed again by the second seal member, This prevents water from entering the valve stem. Therefore, the valve stem is not corroded until the sealing performance of the second seal member is destroyed, so that it can withstand use for a correspondingly long period of time.

(6) Unique effects The second sealing member accommodated in the circular recess and the swelling member accommodated in the second sealing member
As long as the end face of the seal member on the valve body side is not worn and no gap is created between the valve body and the sliding surface of the valve seat (that is, when the seal is secured by the first seal member), both will swell and swell. Since one side of the second seal member does not come into close contact with the first seal member and the other side does not come into close contact with the bottom surface of the circular recess, these two members do not come into close contact with each other when the valve body is opened and closed. There is almost no wear or damage, and the quality at the time of assembly can be maintained until the subsequent second seal member and swelling member exhibit sealing performance, and the sealing performance of the first seal member is improved.
Since the subsequent sealing performance of the second seal member by the swelling member is continued, there is an advantage that maintenance is facilitated without impairing the shaft sealing function during long-term use.

(7) Example In Fig. 1, 1 is the valve box of the butterfly valve, 2,
2' denotes bearing parts provided at the upper and lower parts of the valve box 1;
A rotary valve shaft 3 is supported by bearings 2 and 2', and a valve body 4 is fixed to the inside of the valve body of the valve shaft 3 by a pin 5. Reference numeral 7 denotes an anti-corrosion rubber lining part that covers the inner surface of the valve box 1 in contact with liquid, and this lining part 7 is attached to a valve seat 8 that functions as a sealing member.
have. Reference numeral 10 denotes an anti-corrosion rubber lining portion which similarly coats the liquid-contacted portion of the outer surface of the valve body 4, and this lining portion 10 has a valve seat 11 that slides into contact with the valve seat 8 of the valve body.

In the bearing portion 2 shown in FIG. 2, 13 is a bushing, 14 is a packing holder, 15 is a plurality of packings, and 16 is a packing holder. In the bearing part 2' shown in FIG. 3, 13' is a bush, 18 is a bottom cover, 19 is a jack bolt, 20 is a nut,
21 is a piece, and 22 is a cover.

Further, in FIG. 4, reference numeral 24 denotes a circular recess formed in a part around the valve shaft 3 side on the sliding surface of the valve body valve seat 11 with the valve body valve seat 8. An annular swelling member 26 made of a swelling rubber material that has a rectangular shape and swells to increase its volume when in contact with liquid, and a hollow annular sealing member 28 with a U-shaped cross section, the swelling member 26 is a sealing member. 28 and housed therein. The seal member 28 has one side piece 28a facing the valve box valve seat 8,
The other side piece 28b facing the bottom surface 29 of the circular recess 24
and a connecting piece 28c connecting both side edges 28a and 28b on the valve shaft 3 side, and the connecting piece 28c is fitted onto the valve shaft 3 during the accommodation. One side edge 28a of the seal member 28 is shorter than the width W of the bottom surface 29 of the circular recess 24, that is, a small gap 30 is formed between its tip and the side surface of the recess 24. Further, the other side edge 28b has approximately the same length as the width W, and its tip is in contact with the side surface of the recess 24.

Next, the operation of the above embodiment will be explained.

The valve body side end surface of the valve body valve seat 8 having the function of a sealing member is in sliding contact with the valve body valve seat 11, and the valve body side end surface of the valve body valve seat 8 is not worn, and the sliding surface of the valve body valve seat 11 is maintained. In FIG. 4, which shows a state in which there is no gap between the sealing member 28, one side piece 28a and the other side piece 28b of the sealing member 28 do not come into close contact with the valve box valve seat 8 and the bottom surface 29 of the circular recess 24. Moreover, the swelling member 26 is contracted and accommodated within the sealing member 28. Therefore, in the above state, the valve body valve seat 8 and the valve body valve seat 1
1 maintains a seal and prevents liquid from entering the valve stem 3.

The valve body side end surface of the valve body valve seat 8 that comes into sliding contact with the valve body valve seat 11 gradually wears due to the sliding movement accompanying the opening and closing of the valve body 4, and a gap is formed between the valve body and the sliding surface of the valve body valve seat 11. When this occurs, the liquid in the pipe enters into the circular recess 24 through the small gap 30 from the gap. The infiltration of this liquid causes the swelling member 26 to swell and increase in volume, filling the circular recess 24 . As a result, the sealing member 28 becomes enlarged, and one side piece 28a of the sealing member 28 becomes larger.
is attached to the valve box valve seat 8, and the other side piece 28b is attached to the circular recess 2.
4 (see FIG. 5). Therefore, the liquid is no longer able to enter the valve shaft 3 side by the sealing member 28, and a sealed state is established again. As mentioned above, when the end face of the valve body valve seat 8 on the valve body side is worn out and cannot perform the sealing function, the sealing member 28 performs the sealing function in its place, and the sealing member 2
Since leakage of liquid to the valve stem 3 is reliably prevented until the sealing performance of the valve 8 is destroyed, a safe and reliable seal can be maintained for a long period of time.

In the above, since the liquid-contacted part on the inner surface of the valve body 1 and the liquid-contacted part on the outer surface of the valve body 4 are covered with the anti-corrosion rubber lining parts 7 and 10, this butterfly valve is connected to a corrosive liquid pipe. When used in pipelines, there is no need to further apply anti-corrosion coating, and the product can be installed in the pipeline as is.

In the embodiments described above, the shapes and structures of the sealing member 28 and the swelling member 26 are merely examples, and any shapes and structures other than those shown in the drawings are not prohibited. It goes without saying that the detailed design can also be changed or modified as desired without departing from the gist of the claims for utility model registration.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing an embodiment of this invention in a fully closed state, Fig. 2 is an enlarged sectional view of section A in Fig. 1, Fig. 3 is an enlarged sectional view of section B in Fig. 1, and Fig. 4. is an enlarged sectional view of the main part, and Figure 5 is a fourth diagram for explaining the operation.
FIG. 6 is an enlarged cross-sectional view corresponding to the figure, and FIG. 6 is a longitudinal cross-sectional side view of the main part of the conventional example. 1... Valve box, 2, 2'... Bearing part, 3... Valve stem,
4... Valve body, 7, 10... Rubber lining part, 8
... Valve box valve seat, 11 ... Valve body valve seat, 24 ... Circular recess, 26 ... Swelling member, 28 ... Seal member,
28a...one side piece, 28b...other side piece, 28c...
...Connecting piece, 29...Bottom surface, 30...Small gap.

Claims (1)

[Scope of utility model registration request] In the butterfly valve, an annular first sealing member for sealing around the valve shaft is attached to a valve shaft supported by a bearing part of a valve body, and an end surface thereof on the valve body side is in sliding contact with a valve seat of the valve body. A circular recess is provided in a part of the sliding surface on the valve shaft side that comes into sliding contact with the first sealing member of the body valve seat,
This circular recess has a substantially U-shaped cross section, which has one side piece facing the first sealing member, the other side piece facing the bottom surface of the circular recess, and a connecting piece connecting the both side pieces on the valve shaft side. a hollow annular second sealing member,
The connecting piece is fitted and housed in the valve shaft, and the sealing member swells and increases in volume when it comes into contact with liquid, expanding the second sealing member and making the one side piece become the first sealing member. What is claimed is: 1. A shaft sealing device for a butterfly valve, comprising: a ring-shaped swelling member that brings the other side piece into close contact with the bottom surface of the circular recess.