JP3722615B2 - Plastic butterfly valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic butterfly valve suitably used for piping lines of chemical plants and waterworks, and more particularly to an eccentric plastic butterfly valve in which the valve body can be easily centered when the valve body is closed. Is.
[0002]
[Prior art]
Conventionally, in an eccentric metal butterfly valve, a metal material is used for the main body, the valve body, and the valve shaft, and depending on the fluid flowing through the flow path, a corrosion-resistant metal material is used. Further, a V packing or the like is disposed in the valve shaft shaft hole of the main body in order to prevent leakage from the inside of the main body through the shaft hole. (See Figure 6)
[0003]
On the other hand, in an eccentric plastic butterfly valve with improved corrosion resistance using plastic for the main body and the valve body, an upper cylindrical bush and a lower cylindrical bush are provided to fit the valve shaft into the cylindrical shaft hole. In addition, a valve element position adjusting bolt for centering the valve element is disposed below the lower cylindrical bush. (See Figure 5)
[0004]
[Problems to be solved by the invention]
However, the conventional eccentric plastic butterfly valve has a valve body position adjustment bolt for centering the valve body, which increases the number of parts and the number of parts to be processed. In addition, in order to reduce operating torque and ensure valve seat seal performance, the valve body must be centered with a valve body position adjustment bolt.
[0005]
Further, in the conventional eccentric type metal butterfly valve, the centering of the valve body depends on the dimensional accuracy of each part, and the machining of each part requires precision, which increases the machining cost. Needless to say, the metal eccentric butterfly valve with the valve shaft exposed in the fluid is inferior in corrosion resistance.
[0006]
The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an eccentric plastic butterfly that can easily center the valve body when the valve body is closed in the eccentric butterfly valve. To provide a valve.
[0007]
[Means for Solving the Problems]
The present invention has been made in view of the above prior art, and in an eccentric plastic butterfly valve, the valve body can be easily centered when the valve body is closed, and the valve body can be centered. Since the dimensional accuracy of the parts concerned can be set loosely, the number of machining points can be reduced, the operating torque at the time of opening and closing the valve can be reduced, and uneven wear of the annular seat does not occur.
[0008]
The centering structure of the valve body in the present invention has the following structure.
The upper cylindrical bush is engaged with a bush receiving port provided at the upper part of the main body and a bush receiving port provided at the upper part of the valve body, and the inner surface has a shaft hole with a polygonal section that fits with the valve shaft. An annular seal material is disposed on the outer peripheral surface at a position opposite to the inner peripheral surface of the bush receiving port provided on the upper part of the main body and the inner peripheral surface of the bush receiving port provided on the upper part of the valve body.
[0009]
The lower cylindrical bush has a closed bottom, and is engaged with a bush receiving port provided at the lower part of the main body and a bush receiving port provided at the lower part of the valve body, and the inner surface is fitted with the valve shaft. A shaft hole having a polygonal cross section is provided, and an annular seal member is disposed on the outer peripheral surface at a position facing the inner peripheral surface of the bush receiving port provided in the lower part of the valve body.
[0010]
The upper cylindrical bush is positioned approximately in the valve axis direction by the lower end of the bush presser and the bottom surface of the bush receiving port provided at the upper part of the valve body. Similarly, the lower cylindrical bush is also provided at the lower part of the bush. Positioning in the valve shaft direction is approximately performed by the bottom of the mouth and the upper end surface of the bush receiving port provided at the lower part of the valve body. In addition, the sum of the dimensions in the valve shaft direction of the three members closely fitting the upper cylindrical bush, the valve body, and the lower cylindrical bush is the valve shaft direction between the lower end of the bush presser and the bush receiving bottom of the lower body. It is set to be slightly smaller than the dimensions.
[0011]
That is, between the bottom surface of the upper bushing receptacle of the valve body and the lower end surface of the upper cylindrical bush and the lower end surface of the bush presser and the upper end surface of the upper cylindrical bush when the valve is closed. Both cylindrical bushes, bush pressers or both of the valve bodies are provided so that a slight gap is formed between the upper end surface of the lower cylindrical bush and the upper end surface of the lower bushing receptacle of the valve body. The dimension of the bush receiving port in the valve shaft direction is appropriately set.
[0012]
Here, if the eccentrically arranged valve body is displaced downward in the valve axial direction when the valve is fully opened, for example, when the valve body rotates and the valve tries to close, the peripheral edge of the valve body is the lower part of the annular seat. The contact starts from the inner peripheral side seal portion. Since the valve body is fitted to the valve shaft and the upper and lower cylindrical bushes so as to be movable up and down, the valve body is slightly rotated while being rotated by the repulsive force from the inner circumferential side seal portion of the lower part of the annular seat. Pushed upward. As the valve body further rotates, the valve body is pushed toward the center of the flow path by the repulsive force from the inner circumferential side seal portion of the annular seat as described above, and when the valve is completely closed, The valve body is easily centered by receiving a repulsive force evenly from the inner peripheral seal portion.
[0013]
The sum of the gaps generated when the valve is closed is not particularly limited, but is set to be the same as or smaller than the dimension in the valve axial direction of the annular seal member disposed on the outer peripheral surface of the upper and lower cylindrical bushes on the valve body side. Is good.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.
[0015]
FIG. 1 is a longitudinal sectional view showing a closed state of an eccentric butterfly valve made of vinyl chloride resin.
In the figure, reference numeral 1 denotes a hollow cylindrical main body, and a valve body 2 eccentrically arranged by a hexagonal cross section of a valve shaft 3 is rotatably supported in the interior of the flow path. Reference numeral 4 denotes an annular sheet disposed on the inner peripheral surface of the main body 1, which is fixed to the side surface of the main body 1 by an annular sheet presser 5. Valve seat sealing is ensured.
[0016]
Reference numeral 6 denotes an upper cylindrical bush having an axial hole having a hexagonal cross section for supporting the valve shaft 3 therein, and a bush receiving port 12 provided in the main body 1 and a bush receiving port 13 provided in the valve body 2, respectively. The movement in the valve shaft direction is restricted by the lower end of the bush presser 11 provided on the upper part of the upper cylindrical bush 6 and the bottom surface of the bush receiving port 13 of the valve body 2. On the outer peripheral surface of the upper cylindrical bush 6, annular sealing materials 8 and 9 are fitted in annular holes provided at positions facing the inner peripheral surfaces of the bush receiving ports 12 and 13, respectively. The flowing fluid is sealed by the annular seal members 8 and 9 so that the valve shaft 3 does not directly contact the fluid.
[0017]
Similarly, reference numeral 7 denotes a lower cylindrical bush having a closed bottom portion and a shaft hole having a hexagonal cross section, and a bush receiving port 16 provided in the lower portion of the main body 1 and a bush receiving port provided in the valve body 2. 15 is fitted over both, and the inside is fitted with the valve shaft 3 to support the valve shaft 3. An annular seal member 10 is fitted into an annular hole provided on the outer peripheral surface of the lower cylindrical bush 7 so as to face the inner peripheral surface of the bush receiving port 15, and the fluid flowing in the flow path is caused by the annular seal member 10. The valve shaft 3 is sealed so as not to directly contact the fluid.
[0018]
14 and 17 are between the lower end surface of the bush presser 11 and the upper end surface of the upper cylindrical bush 6, and between the upper end surface of the bush receiving port 15 provided at the lower part of the valve body 2 and the upper end surface of the lower cylindrical bush 7. It is a gap provided between each.
[0019]
The reason for providing the gaps 14 and 17 is as follows.
The valve body 2 is positioned in the valve shaft direction by the upper cylindrical bush 6 and the lower cylindrical bush 7, but it is necessary that the peripheral edge of the valve body 2 and the annular seat 4 are in uniform pressure contact when the valve is closed. However, if there is no gap between the valve body 2 and the upper cylindrical bush 6 and the lower cylindrical bush 7, the position of the valve body is determined when the valve is assembled, so the valve shaft of the valve body 2 when the valve is closed. The position in the direction depends on the dimension of each component in the valve shaft direction.
[0020]
On the other hand, when the clearances 14 and 17 are provided as in the present invention, the valve body 2 can be moved in the valve axis direction when the valve body 2 is rotated to close the valve. It becomes easy to take out. The dimension of the clearances 14 and 17 in the valve axis direction is slightly smaller than the dimension of the annular sealing materials 9 and 10 in the valve axis direction. The gap 14 may be provided between the lower end surface of the upper cylindrical bush 6 and the bottom surface of the bush receiving port 13 provided in the upper portion of the valve body 2.
[0021]
FIG. 4 is a longitudinal sectional view showing a closed state of another embodiment of an eccentric butterfly valve made of a vinyl chloride resin, and the upper cylindrical bush 18 has a deeper fitting depth with the valve body 2. It has a stable shaft seal structure. Further, the lower cylindrical bush 19 is obtained by adding an annular sealing material 21 to the outer peripheral surface of the lower cylindrical bush 7 shown in FIG. 1, and is a lower cylindrical shape facing the inner peripheral surface of the bush receiving port provided in the lower part of the main body. An annular sealing member 21 is disposed on the outer peripheral surface of the bush 19 to suppress a phenomenon that the valve shaft 3 is pushed upward in the valve shaft direction depending on the fluid pressure when the valve is opened.
[0022]
【The invention's effect】
As described above, the eccentric plastic butterfly valve according to the present invention has a valve body in the valve closed state by providing a gap in the valve axial direction between the upper and lower cylindrical bushes and the valve body so that the valve body can be slightly moved up and down. Since positioning is performed easily, there is no need to set the dimensional accuracy of the upper and lower cylindrical bushes and the valve body in the valve axis direction, the processing cost can be reduced, and uneven wear of the annular seat does not occur. Seat seal performance can be maintained over a long period of time.
[0023]
In addition, if an annular seal is placed on the main body and valve body side of the outer peripheral surface of the upper and lower cylindrical bushes so that the valve shaft is not in direct contact with the fluid flowing in the flow path, the valve shaft is corroded by the fluid. The valve stem can be selected from a wide range of materials, reducing the material cost and improving the strength of the valve stem, and preventing the valve stem from sticking to other parts. Can keep.
[0024]
Furthermore, the cost required for production and maintenance can be reduced.
Needless to say, since it is made of plastic, it is lightweight and has excellent corrosion resistance.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a valve closed state according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of a valve body, a valve shaft, and upper and lower cylindrical bushes.
FIG. 3 is a longitudinal sectional view showing when the valve of FIG. 1 is open.
FIG. 4 is a longitudinal sectional view showing another embodiment of the present invention.
FIG. 5 is a longitudinal sectional view of a conventional plastic butterfly valve.
FIG. 6 is a longitudinal sectional view of a conventional metal butterfly valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main body 2 ... Valve body 3 ... Valve shaft 4 ... Ring seat 5 ... Sheet presser 6 ... Upper cylindrical bush 7 ... Lower cylindrical bush 8 ... Ring seal material 9 ... Ring seal material 10 ... Ring seal material 11 ... Bush presser 12 ... Bush receptacle 13 ... Bush receptacle 14 ... Gap 15 ... Bush receptacle 16 ... Bush receptacle 17 ... Gap 18 ... Upper cylindrical bush 19 ... Lower cylindrical bush 20 ... Annular seal material 21 ... Annular seal material 22 ... Handle 23 ... Bolt hole 41 ... Main body 42 ... Valve body 43 ... Valve shaft 44 ... Annular seat 45 ... Upper bush 46 ... Lower bush 47 ... Annular seal material 48 ... Adjustment bolt 49 ... Lock nut 50 ... Thrust receiver 61 ... Main body 62 ... Valve body 63 ... Valve shaft 64 ... Annular sheet 65 ... V packing presser 66 ... V packing 67 ... Gasket

Claims (3)

An annular sheet is fixed to the inner peripheral side surface of the hollow cylindrical main body from the side of the main body, and the peripheral edge of the valve body pivotally supported so as to be fitted to the valve shaft having a polygonal cross section and to rotate eccentrically in the main body In an eccentric plastic butterfly valve configured to abut against a seat, a cross-section in which a bush receiving port is provided on each of the upper part of the main body and the valve body, and the valve shaft is fitted so as to engage with both the bush receiving ports. An upper cylindrical bush having a polygonal shaft hole is fitted, and a lower cylindrical bush with a bottom having a shaft hole similar to the above is provided in a bush receiving port provided in the lower part of the main body and the valve body. Fitted in the same manner as the cylindrical bush, a bush presser is provided on the upper cylindrical bush to fit the valve shaft and restrict the upward movement of the upper cylindrical bush, and further, the end surface of the upper cylindrical bush and the Valve body or bush A slight gap is provided between the presser and between the end face of the lower cylindrical bush and the valve body, and the upper and lower cylindrical bushes are fitted so that the valve body can move slightly up and down relative to the main body when the valve is opened and closed. A plastic butterfly valve. 2. The plastic butterfly valve according to claim 1, wherein an annular sealing material is disposed between the upper cylindrical bush and the main body and the valve body, and between the lower cylindrical bush and the valve body. The plastic butterfly valve according to claim 1 or 2, wherein the plastic is hard vinyl chloride resin, polypropylene, or fluororesin.

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