Butterfly valve

Abstract

The present application discloses a butterfly valve. The butterfly valve comprises: a valve body, an inner valve seat, a valve core, a valve stem and at least one positioning ring. The valve body has an inlet end and an outlet end and an axial channel connecting the inlet end and the outlet end. A valve stem mounting hole is provided in the valve body between the inlet end and the outlet end in a radial direction. A valve seat mounting portion is provided inside the valve body at a position corresponding to the valve stem mounting hole. The inner valve seat is fixedly mounted on the valve seat mounting portion, and the inner valve seat is a cylindrical member and a radial through hole corresponding to the valve stem mounting hole is provided on its side wall. The valve core is a plate-shaped member and is installed in the inner valve seat, wherein a radial through hole is provided inside the plate-shaped member. The valve stem passes through the valve stem mounting hole, the through hole of the inner valve seat and the through hole of the valve core in sequence; the positioning ring is installed inside the valve body on the axial side of the inner valve seat and forms a sealing connection with the inner valve seat. The butterfly valve of the present application has good sealing performance.

Description

Technical Field

[0001] The invention relates to a valve, in particular to a butterfly valve. Background Art

[0002] The existing butterfly valve is opened by rotating the middle shaft of the valve core, which drives the two sides of the valve core to rotate and open, and the sealing performance is usually poor. Especially when the butterfly valve is mainly made of plastic, its sealing performance is even worse after high-temperature sterilization. Summary of the invention

[0003] The object of the present invention is to provide a butterfly valve with good sealing performance.

[0004] To achieve the above object, the present invention provides a butterfly valve, the butterfly valve comprising:

[0005] A valve body, the valve body having an inlet end and an outlet end and an axial passage connecting the inlet end and the outlet end, a valve stem mounting hole along a radial direction is provided on the valve body between the inlet end and the outlet end, and a valve seat mounting portion is provided inside the valve body at a position corresponding to the valve stem mounting hole;

[0006] An inner valve seat, the inner valve seat is fixedly mounted on the valve seat mounting portion, the inner valve seat is a cylindrical member and has a radial through hole on its side wall corresponding to the valve stem mounting hole;

[0007] A valve core, the valve core is a plate-shaped member and is installed in the inner valve seat, wherein a through hole along the radial direction is provided inside the plate-shaped member;

[0008] A valve stem, the valve stem sequentially passing through the valve stem mounting hole, the through hole of the inner valve seat and the through hole of the valve core; and

[0009] At least one positioning ring is installed inside the valve body on the axial side of the inner valve seat and forms a sealing connection with the inner valve seat.

[0010] In one embodiment, the positioning ring is arranged so that the valve body and the inner valve seat form a sealed connection under the action of the positioning ring.

[0011] In one embodiment, the positioning ring is arranged such that it exerts a pressing effect on the inner valve seat.

[0012] In one embodiment, a sealing connection is formed between the inner valve seat and the valve body.

[0013] In one embodiment, a sealing surface is provided in the valve body, a sealing rib cooperating with the sealing surface of the valve body is provided on the inner valve seat, and the inner valve seat is also provided with a sealing surface, and the positioning ring is provided with a sealing rib cooperating with the sealing surface of the inner valve seat.

[0014] In one embodiment, a hanging platform is provided on the outer peripheral surface of the positioning ring, and an undercut matching with the hanging platform is provided inside the valve body.

[0015] In one embodiment, the valve is provided with two positioning rings, and the two positioning rings are respectively sealed and connected to the front side and the rear side of the inner valve seat.

[0016] In one embodiment, the valve body is cylindrical and has a front section, a middle section and a rear section, wherein the inner diameter of the internal channel of the middle section is smaller than the inner diameters of the internal channels of the front section and the rear section, and there are sealing surfaces formed by shoulders between the internal channel of the middle section and the internal channels of the front section and the rear section.

[0017] In one embodiment, a sealing surface is provided in the valve body, and the positioning ring is provided on both axial sides of the inner valve seat. The inner valve seat is cylindrical and has a rear end and a front end. The rear end and the front end are both provided with flanges protruding radially outward, wherein one side annular surface of each flange forms a sealing contact with the sealing surface of the valve body, and the other side of the flange forms a sealing contact with the sealing surface of the positioning ring.

[0018] In one embodiment, a sealing rib is provided on the annular surface of the flange that forms a sealing contact with the valve body, and a sealing rib is provided on the sealing surface of the positioning ring that faces the flange.

[0019] In one embodiment, a metal pin extending along the axial direction of the valve stem is inserted into the interior of the valve stem.

[0020] In one embodiment, the valve is further provided with an outer valve seat, and the outer valve seat is mounted against the positioning ring.

[0021] In one embodiment, the valve body, the inner valve seat, the valve core and the positioning ring are all made of plastic.

[0022] The beneficial effects of the present invention are that the number of transmission parts is small, the manufacturing process is good, the structure is simple, the space utilization rate is high, the valve can be minimized, the opening torque is small, and the sealing performance is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of an exploded view of a butterfly valve according to the present invention.

[0024] Figure 2 is an axial cross-sectional view of a butterfly valve according to the present invention.

[0025] Figure 3(a) and 3(b) They are three-dimensional views of the front locating ring and the rear locating ring of the butterfly valve according to the present invention.

[0026] Figure 4(a)and 4(b) The three-dimensional views are respectively of a valve body of a butterfly valve according to the present invention as viewed from the front side and the rear side.

[0027] FIG. 5( a ) is a perspective view of a positioning rod and a handle of a butterfly valve according to the present invention.

[0028] FIG5( b ) is a perspective view of a metal pin in a positioning rod and a longitudinal cross-sectional view of the positioning rod.

[0029] Figure 6(a) and 6(b) They are respectively a stereoscopic view and an axial cross-sectional view of a valve core of a butterfly valve according to the present invention.

[0030] FIG. 7( a ) is a perspective view of a valve seat of a butterfly valve according to the present invention as viewed from the rear side.

[0031] FIG. 7( b ) is an axial cross-sectional view of the valve seat of the butterfly valve according to the present invention.

[0032] FIG8( a ) is an exploded perspective view of the valve body, the front positioning ring, the rear positioning ring, and the inner valve seat of the butterfly valve according to the present invention.

[0033] 8( b ) is an axial cross-sectional view of the valve body, the front positioning ring, the rear positioning ring, and the inner valve seat of the butterfly valve according to the present invention.

[0034] FIG. 9( a ) is an assembled stereogram of a valve body, a front locating ring, a rear locating ring, and an outer valve seat of a butterfly valve according to the present invention.

[0035] 9( b ) is an assembled axial cross-sectional view of the valve body, the front positioning ring, the rear positioning ring, and the outer valve seat of the butterfly valve according to the present invention.

[0036] Fig.10 1 is a perspective view of a butterfly valve according to the present invention when the valve is in an open state as viewed from the front side. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0038] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, well-known devices, structures, and techniques associated with the present application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0039] Unless the context requires otherwise, throughout the specification and claims, the word "comprise" and variations such as "include" and "have" should be construed in an open, inclusive sense, ie, should be interpreted as "including, but not limited to."

[0040] References throughout the specification to "one embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0041] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "and / or" unless the context clearly dictates otherwise.

[0042] In the following description, in order to clearly illustrate the structure and working mode of the present invention, a number of directional terms will be used for description, wherein "front" and "rear" refer to Figure 1 and Figure 2 The left and right directions, "outside", "inside", "outward", "inward", "up", "down", etc. are understood as convenient terms and should not be understood as restrictive terms.

[0043] The butterfly valve 100 according to the present invention is first described in detail with reference to the accompanying drawings. The butterfly valve 100 is generally used for the outlet of a container and is generally made of plastic material. Figure 1 and 2 As shown in Figure 1 As shown, the butterfly valve 100 includes: a valve body 101, a valve stem 102, a valve core 103, an inner valve seat 104, an outer valve seat 105, a front positioning ring 106, a rear positioning ring 107 and a handle 108. Figure 2 , the inner valve seat 104 is installed in the valve body 101, the valve core 103 is installed in the inner valve seat 104, and the front locating ring 106 and the rear locating ring 107 are respectively located at the front side and the rear side of the inner valve seat 104. It should be understood that only the front locating ring 106 or only the rear locating ring 107 can be provided without departing from the scope of the present invention. Here, the locating rings 106 and 107 are parts independent of the valve body 101. Because it is convenient to replace or to use more suitable materials. The outer valve seat 105 is arranged on the front side of the inner locating ring 106 (if any) of the valve body 101. The valve cover 111 is arranged on the front side of the valve body 101. A flange 110 is also installed on the rear side of the valve body 101. The flange sealing ring 109 is arranged between the valve body 101 and the flange 110. An anti-theft buckle 112 can be installed on the front side of the valve cover 111.

[0044] Specifically, see further Figure 8(a) and 8(b) The valve body 101 is a substantially cylindrical integral structure, having an outlet end 113 and an inlet end 114, and an axial passage connecting the outlet end 113 and the inlet end 114. The valve body 101 comprises a front section 1011, a middle section 1012 and a rear section 1013 which are connected to each other in succession. The front section 1011, the middle section 1012 and the rear section 1013 are all substantially cylindrical and have corresponding internal passages to jointly form the internal passage of the valve body 101. The middle section 1012 forms a valve seat mounting portion for accommodating the inner valve seat 104.

[0045] In the illustrated embodiment, the inner diameter of the inner channel of the middle section 1012 is smaller than the inner diameter of the inner channel of the front section 1011, and is also smaller than the inner diameter of the inner channel of the rear section 1013. Sealing surfaces 1014a and 1014b formed by shoulders are respectively provided between the inner channel of the middle section 1012 and the inner channels of the front section 1011 and the rear section 1013. The sealing surfaces 1014a and 1014b are annular surfaces facing the front side and the rear side, respectively.

[0046] Undercuts 1015 are also provided on the inner surfaces of the inner passages of the front section 1011 and the rear section 1013, so as to prevent the front locating ring 106 and / or the rear locating ring 107 from coming out of the inner passages when the front locating ring 106 is installed from the front side to the rear side into the inner passage of the front section 1011 and / or the rear locating ring 107 is installed from the rear side into the inner passage of the rear section 1013. The undercuts 1015 are in the form of, for example, circumferential ridges in the front section 1011 pointing backward and circumferential ridges in the rear section 1013 pointing forward. In the illustrated embodiment, four undercuts 1015 are provided in the front section 1011 and the rear section 1013, each spaced apart in the circumferential direction. Of course, other numbers, forms and arrangements may also be adopted, as long as resistance is applied when the front locating ring 106 and the rear locating ring 107 are withdrawn from the valve body 101.

[0047] The outer circumferential surfaces of the front section 1011 and the rear section 1013 are respectively provided with connection structures for matching with the valve cover 111 and the flange 110. In the illustrated embodiment, the connection structure is an external thread, but it should be understood that the connection structure can also be other known connection structures such as a snap-fit ​​protrusion or a snap-fit ​​groove.

[0048] See also Figure 1 , Figure 4(a)-4(b) ,as well as Figure 8(a)-8(b)A radial through hole 1016 is provided on the circumferential wall of the middle section 1012 for inserting the valve stem 102. Accordingly, a counterbore 1017 is provided in the radial wall at a position diametrically opposite to the radial through hole 1016, and when the valve stem 102 is inserted therein, the counterbore 1017 is used to accommodate the end of the valve stem 1017.

[0049] See also Figure 7(a)-7(b) The inner valve seat 104 is generally cylindrical and has two axial ends, namely, a rear end and a front end. Two through holes 1043 and 1044 with opposite diameters are provided on the circumferential wall of the inner valve seat 104 for the valve stem 102 to be inserted through. Flanges 1041 and 1042 protruding radially outward are provided at the rear end and the front end of the inner valve seat 104, respectively. The annular surface 1041a of the flange 1041 facing forward (downward in the figure) is used to form a sealing contact with the sealing surface 1014b of the valve body 101, while the annular surface 1041b facing backward (upward in the figure) is used to form a sealing contact with the sealing surface 1071 (see below) of the rear positioning ring 107. The annular surface 1042a of the flange 1042 facing backward (upward in the figure) is used to form a sealing contact with the sealing surface 1014a of the valve body 101, while the annular surface 1042b facing forward (downward in the figure) is used to form a sealing contact with the sealing surface 1061 of the front positioning ring 106. Among the pairs of surfaces that form a sealing contact with each other: the annular surface 1041a and the sealing surface 1014b; the annular surface 1041b and the sealing surface 1071; the annular surface 1042a and the sealing surface 1014a; the annular surface 1042b and the sealing surface 1061, at least one of the surfaces may be provided with a sealing rib 115. In the illustrated embodiment, the sealing rib 115 is provided on the annular surface 1041a and the annular surface 1042a and the sealing surfaces 1061 and 1071. The pressurized contact between the sealing rib 115 and the corresponding annular surface or sealing surface can form a good seal.

[0050] A circumferential sealing rib 1046 is also provided on the inner circumferential surface 1045 of the inner valve seat 104. The centers of the through holes 1042 and 1043 are located on the circle where the circumferential sealing rib 1046 is located. The circumferential sealing rib 1046 extends around the entire outer circumference of the two through holes 1042 and 1043 on the inner circumferential surface 1045 of the inner valve seat 104, as shown in FIG. 7(a). The pressurized contact between the circumferential sealing rib 1046 and the valve core sealing surface 1031a (described below) of the valve core 103 can form a good sealing effect.

[0051] Preferably, in order to facilitate the installation of the inner valve seat 104 in the valve body 101, the flanges 1041 and 1042 of the inner valve seat 104 can be set to have a smaller outer diameter (flange 1042 is shown in the figure), so that the flange with the smaller outer diameter is first passed through the valve seat installation portion of the valve body 101, thereby installing the inner valve seat 104 in place.

[0052] Preferably, in order to facilitate the installation of the valve core 103, the inner circumferential surface of the inner valve seat 104 located in front and rear of the circumferential sealing rib 1046 may be tapered with the inner diameter slightly expanding toward both ends.

[0053] See also Figure 6(a) and 6(b) The valve core 103 is in a generally circular plate shape, and a generally cylindrical valve rim 1031 is provided around the outer circumference of the circular plate, and the outer circumferential surface of the valve rim 1031 is used as a valve core sealing surface 1031a. In addition, a through hole that radially passes through its diameter is provided in the valve core 103 to serve as a valve stem mounting hole 1032. In order to make the valve core 103 lighter, the circular plate portion of the valve core 103 can be set to be relatively thin, while the portion provided with the valve stem mounting hole 1032 is relatively thick, thereby forming a valve stem mounting hole 1032 with a relatively large inner size. Preferably, a valve core protrusion 1034 is installed on the inner circumferential surface of the valve stem mounting hole 1032. In the illustrated embodiment, a pair of valve core protrusions 1034 are provided opposite to each other, but it should be understood that other appropriate positions and a suitable number of valve core protrusions 1034 can be provided as needed.

[0054] In the illustrated embodiment, the valve core sealing surface 1031a is able to form a sealing contact with the inner peripheral surface 1045 of the inner valve seat 104 due to the sealing ribs 1046 on the inner peripheral surface 1045. However, it should be understood that the sealing ribs may also be provided on the valve core sealing surface 1031a and around the outer periphery of the valve stem mounting hole 1032 instead of on the inner peripheral surface 1045.

[0055] The valve stem mounting hole 1032 is used to accommodate the valve stem 102. FIG. 5( a ) shows a three-dimensional view of the valve stem 102. The valve stem 102 includes a valve stem body 1021. The cross-sectional shape of the valve stem body 1021 is complementary to the cross-sectional shape of the valve stem mounting hole 1032. However, it should be understood that the cross-sectional shape should be a non-circular shape so that the valve stem 102 cannot rotate in the valve stem mounting hole 1032, so that the rotation of the valve stem 102 can drive the rotation of the valve core 103. In the illustrated embodiment, the cross-sectional shape of the valve stem body 1021 is roughly rectangular. And a valve stem limiting concave point 1022 is provided on the outer peripheral surface of the valve stem body 1021. The limiting concave point 1022 is roughly complementary to the shape of the valve core protrusion 1034, and the position and number of the limiting concave point 1022 correspond to the position and number of the valve core protrusion 1034. The valve stem 102 and the valve core 103 are assembled by the valve stem limiting concave point 1022 and the valve core convex point 1034, and are not easy to fall off after assembly. The valve stem body 1021 is also provided with an axial hollow channel, and a metal pin 1023 is installed in the axial hollow channel, as shown in Figure 5(b). Since the metal pin 1023 is assembled in the valve stem 102, the deformation of the valve core 103 caused by high temperature can be resisted in the case of high temperature steam sterilization. This makes the sealing performance of the butterfly valve 100 able to withstand high temperature and high pressure, meeting the use requirements.

[0056] A handle receiving structure 1023 is provided at the head of the valve stem 102. The handle receiving structure 1023 is two protrusions provided with pin holes. The handle 108 has a cam portion 1081, which can be installed between the two protrusions. Pins are provided on both sides of the cam portion 1081. The pins can be inserted into the pin holes of the handle receiving structure 1023, and the handle 108 can rotate around the pins. The rotation of the handle 108 around the longitudinal circumference of the valve stem 102 can drive the valve stem 102, thereby driving the valve core 103 to rotate to open or close the butterfly valve 100.

[0057] See also Figure 3(a) and 3(b) , respectively show stereoscopic views of the front positioning ring 106 and the rear positioning ring 107. The rear end surface of the front positioning ring 106 is the sealing surface 1061, and the front end surface of the front positioning ring 1071 is the sealing surface 1071. An annular sealing rib 115 is provided on the sealing surfaces 1061 and 1071, and is used to form a sealing contact with the annular surface 1042b and the annular surface 1041b of the inner valve seat 104, respectively. However, it should be understood that the annular sealing rib 115 can also be formed on the annular surface 1042b and the annular surface 1041b instead of the sealing surfaces 1061 and 1071. The pressurized contact between the sealing rib 115 and the relative sealing surface or annular surface can form a good sealing effect.

[0058] Preferably, the outer circumferential surfaces of the front positioning ring 106 and the rear positioning ring 107 are also provided with hanging platforms 1062 and 1072, respectively. Figure 3(a) and 3(b) 8(b) shows an axial cross-sectional view of the valve body 101, the front locating ring 106, the rear locating ring 107, and the inner valve seat 104. The hanging platforms 1062 and 1072 are shown. The hanging platforms 1062 and 1072 are in the form of circumferential rings protruding forward and backward respectively, so as to cooperate with the undercut 1015 to prevent the front locating ring 106 and the rear locating ring 107 from withdrawing from the valve body 101.

[0059] In addition, a valve cover 111 is provided on the front side of the valve body 101. Figure 1 The valve cover 111 has a circular cover plate 1111 and a circumferential cover edge 1112 extending from the outer periphery of the cover plate 1111 to the rear side. A connection structure such as a thread is provided on the inner side of the circumferential cover edge 1112 for cooperating with a matching connection structure such as a thread on the outer peripheral surface of the front side of the valve body 101, so that the valve cover 111 can be fastened to the valve body 101.

[0060] More preferably, an anti-theft buckle 112 may be further provided on the front side of the valve cover 111. In this case, a recessed portion for accommodating the anti-theft buckle 112 may be provided on the front side of the valve cover 111. The anti-theft buckle 112 has a main body 1121 and a buckle arm 1122 extending from the diametrically opposite position of the main body 1121 to the rear side, and a hook portion 1123 extending radially inward is provided at the end of the buckle arm 1122. Accordingly, two notches 1113 are provided at the diametrically opposite positions of the circumferential cover edge 1112 of the valve cover 111 for accommodating the two buckle arms 1122. Two concave cavities may be provided at corresponding positions on the outer periphery of the front side of the valve body 101, respectively for accommodating the hook portions 1123 of the two buckle arms 1122. Due to the presence of the anti-theft buckle 112, the valve cover 111 cannot be removed from the valve body 101 without removing the anti-theft buckle 112.

[0061] Preferably, an outer valve seat 105 is provided between the front positioning ring 106 and the valve cover 111. The outer valve seat 105 is located between the front end surface of the front positioning ring 106 and the valve cover 111, and forms a seal therebetween. Figure 2 8(b), the outer valve seat 105 is generally annular, and its inner circumference is provided with a step portion, so that it can abut against the front end surface of the front positioning ring 106 and be positioned around the outer circumferential front edge. The outer valve seat 105 is preferably made of elastic material, and when the valve cover 111 is fastened in place on the valve body 101, the outer valve seat 105 is in a compressed state.

[0062] A flange 110 is also provided on the rear side of the valve body 101. The flange 110 is substantially cylindrical and has a flange 1101 extending radially outward from the outer peripheral surface of the flange 110. A connection structure such as a thread is provided on the inner peripheral surface of the flange 110 to match the connection structure on the outer peripheral surface of the rear side of the valve body 101, thereby forming a tight connection. A flange sealing ring 109 is also provided between the flange 110 and the rear end surface of the valve body 101. Figure 2 As shown, an annular groove 1102 is provided on the inner circumferential surface of the flange 110 for accommodating the flange sealing ring 109. When in use, the flange 110 is often fixedly connected to the bulk container by welding or the like. The flange sealing ring 109 is made of an elastic material, and when the flange 110 and the valve body 101 are fastened in place relative to each other, the flange sealing ring 109 is in a compressed state.

[0063] In the above embodiment, the sealing ribs 1046 on the inner circumferential surface 1045 of the inner valve seat 104 and the valve core sealing surface 1031a of the valve core 103, and the sealing ribs 1041b and / or 1042b of the inner valve seat 104 and the sealing surface 1071 of the rear positioning ring 107 and / or the sealing surface 1061 of the front positioning ring 106 respectively form a seal with the corresponding surface. The sealing effect is good and can ensure that no leakage occurs under high temperature and high pressure. In addition, the sealing structure between the valve stem 102 and the valve stem mounting hole 1032 can ensure the sealing of the butterfly valve 100 relative to the outside without providing a sealing structure.

[0064] Preferred embodiments of the present invention have been described above in detail, but it should be understood that aspects of the embodiments can be modified, if necessary, to employ aspects, features and concepts of the various patents, applications and publications to provide further embodiments.

[0065] These and other changes can be made to the embodiments in light of the above detailed description.In general, in the claims, the terms used should not be considered limited to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which these claims are entitled.

Claims

1. A butterfly valve, characterized in that: The butterfly valve comprises: A valve body, the valve body having an inlet end and an outlet end and an axial passage connecting the inlet end and the outlet end, a valve stem mounting hole along a radial direction is provided on the valve body between the inlet end and the outlet end, and a valve seat mounting portion is provided inside the valve body at a position corresponding to the valve stem mounting hole; An inner valve seat, the inner valve seat is fixedly mounted on the valve seat mounting portion, the inner valve seat is a cylindrical member and has a radial through hole on its side wall corresponding to the valve stem mounting hole; A valve core, the valve core is a plate-shaped member and is installed in the inner valve seat, wherein a through hole along the radial direction is provided inside the plate-shaped member; A valve stem, the valve stem sequentially passing through the valve stem mounting hole, the through hole of the inner valve seat and the through hole of the valve core; and The inner valve seat is provided with positioning rings on both axial sides, the positioning rings are installed inside the valve body on the axial side of the inner valve seat and form a sealing connection with the inner valve seat; the inner valve seat has a rear end and a front end, the rear end and the front end are provided with flanges protruding radially outward, wherein one side annular surface of each flange forms a sealing contact with the sealing surface of the valve body, and the other side annular surface of the flange forms a sealing contact with the sealing surface of the positioning ring; the positioning ring is arranged so that it exerts an extrusion effect on the inner valve seat; The valve body is provided with a sealing surface, the inner valve seat is provided with a sealing rib that matches the sealing surface of the valve body, and the inner valve seat is also provided with a sealing surface, and the positioning ring is provided with a sealing rib that matches the sealing surface of the inner valve seat; A seal is formed between the sealing surface of the valve body and the annular surface of the inner valve seat, and between the annular surface of the inner valve seat and the sealing surface of the rear positioning ring and / or the sealing surface of the front positioning ring through sealing ribs and corresponding surfaces.

2. The butterfly valve according to claim 1, characterized in that: A sealing connection is formed between the inner valve seat and the valve body.

3. The butterfly valve according to claim 1, characterized in that: The positioning ring is arranged so that the valve body and the inner valve seat form a sealed connection under the action of the positioning ring.

4. The butterfly valve according to claim 1, characterized in that: A hanging platform is arranged on the outer peripheral surface of the positioning ring, and an undercut matching with the hanging platform is arranged inside the valve body.

5. The butterfly valve according to claim 1, characterized in that: The butterfly valve is provided with two positioning rings, and the two positioning rings are respectively sealed and connected with the front side and the rear side of the inner valve seat.

6. The butterfly valve according to claim 1, characterized in that: The valve body is cylindrical and has a front section, a middle section and a rear section, wherein the inner diameter of the internal channel of the middle section is smaller than the inner diameters of the internal channels of the front section and the rear section, and there are sealing surfaces formed by shoulders between the internal channel of the middle section and the internal channels of the front section and the rear section.

7. The butterfly valve according to claim 1, characterized in that: A sealing rib is provided on the annular surface of the flange that forms a sealing contact with the valve body, and a sealing rib is provided on the sealing surface of the positioning ring that faces the flange.

8. The butterfly valve according to claim 1, characterized in that: A metal pin extending along the axial direction of the valve stem is inserted into the interior of the valve stem.

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