JPH0472112B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a butterfly valve having a body and a closure disc supported on the body for movement between an open position and a closed position.

[Prior art]

Butterfly valves, which are widely used for flow control in piping systems for various fluids, are disclosed, for example, in Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Publication No. 90815 or Japanese Patent Publication No. 56-31464, it comprises a main body and a closing disk supported by the main body so as to be movable between an open position and a closed position. At least one stem portion receiving hole is formed in the main body, and the at least one stem portion disposed on the closing disk is inserted into the stem portion receiving hole so that the closing disk is in the closed position. It is attached to the main body so as to be movable between the open position and the open position.

[Problems with conventional technology]

However, the conventional butterfly valve has the following problem regarding the seal between the stem portion receiving hole of the main body and the stem portion of the closing disk inserted into the stem portion receiving hole.

In the butterfly valve disclosed in Japanese Patent Publication No. 56-31464, an annular packing is arranged around the stem portion of the closing disk, and the annular packing is compressed in the stem axis direction by the action of a cylindrical screw. The stem portion is bulged inward and outward in the radial direction, and the annular packing is thus pressed against both the outer circumferential surface of the stem portion and the inner circumferential surface of the stem portion receiving hole, thereby sealing the space between the two. Such a sealing style has problems in that adjusting the tightening force of the cylindrical screw during assembly is not easy and requires skill, and the sealing action is not necessarily sufficient.

In the butterfly valve disclosed in JP-A No. 52-90815, the stem portion of the closing disk has a first annular shape extending annularly around the stem portion and facing outward in the axial direction of the stem. A first elastic sealing means having a sealing surface is disposed on the main body, and the first elastic sealing means extends annularly around the stem portion on the outer side in the stem axial direction and faces inward in the stem axial direction and has the first annular sealing surface. A second resilient sealing means is provided having a second annular sealing surface opposite the second resilient sealing means. The first annular sealing surface and the second annular sealing surface are brought into close contact with each other by their own elasticity as well as the elasticity of the elastomer backing up the second elastic sealing means to form a seal. do. Furthermore, a stationary washer, an annular gasket, a movable bearing and a coil spring are disposed around the stem portion of the closing disc in sequence in the axial direction of the stem. The coil spring compresses the annular gasket against the stationary washer inwardly in the axial direction of the stem;
In this manner, the annular gasket is bulged in and out of the stem portion in the radial direction and is pressed against the outer circumferential surface of the stem portion and the inner circumferential surface of the stem receiving hole. However, such sealing styles also have problems that need to be resolved. First, the first annular sealing surface and the second annular sealing surface
The close contact with the annular sealing surface is not always sufficient since it depends on their own elasticity and the elasticity of the elastomer backing up the second elastic sealing means, and therefore the sealing action is not always sufficient. Otherwise, problems such as fine particles contained in the flowing liquid entering between the first elastic sealing surface and the second elastic sealing surface may occur. The coil spring acts to press the annular gasket against the stationary washer,
This does not contribute at all to the mutual close contact between the first annular sealing surface and the second annular sealing surface. Second, in order to obtain a sufficiently large required elastic bias force with the coil spring for compressing the annular gasket against the stationary washer, it is necessary that the effective elastic stretch length of the coil spring be considerably long. . Therefore,
During assembly, it is necessary to compress the coil spring to a considerable length, and during disassembly, the compressed coil spring must be expanded to a considerable length, thus making assembly and Disassembly work is not always easy.

[Technical problem of the invention]

The technical problem of the present invention is to improve the sealing style between the stem receiving hole of the main body and the stem part of the closing disc in a butterfly valve so that a sufficient sealing effect is achieved, and also to assemble the valve. and to enable the decomposition to be carried out sufficiently easily and quickly.

[Means for solving the invention]

The solution of the present invention provides (a) a first tube extending annularly around the stem portion and facing outward in the axial direction of the stem;
(b) a first elastic sealing means having an annular sealing surface disposed on the closure disk; a second elastic sealing means having a second annular sealing surface facing inward in the stem axial direction and opposing the first annular sealing surface;
(c) comprising at least one plate spring, the second elastic sealing means is configured to elastically bias the second elastic sealing means inward in the stem axial direction, and the second elastic sealing means is disposed on the first annular sealing surface; (d) an elastic biasing means for elastically pressing the annular sealing surface of the stem; A cylindrical pusher plug is arranged to be movable in the axial direction, and the elastic biasing force of the elastic biasing means is transmitted to the second elastic sealing means via the pusher plug.

That is, according to the present invention, there is provided a main body in which at least one stem portion accommodating hole extending in the stem axial direction is formed; a closure disk inserted into the body and supported by the main body so as to be movable between an open position and a closed position; a closure disk disposed on the closure disk and extending annularly around the stem portion; a first resilient sealing means having a first annular sealing surface facing axially outward; a second elastic sealing means having a second annular sealing surface extending annularly around the periphery and facing inward in the axial direction of the stem and opposing the first annular sealing surface; and the second elastic seal. within the receiving bore and around the stem for resiliently biasing means axially inwardly of the stem to resiliently press the second annular sealing surface against the first annular sealing surface; an elastic biasing means constituted by at least one disc spring disposed in the second elastic sealing means and the elastic biasing means, and moving in the stem axial direction between the second elastic sealing means and the elastic biasing means and around the stem portion; A butterfly valve is provided, comprising: a cylindrical pusher plug freely disposed and transmitting the elastic biasing force of the elastic biasing means to the second elastic sealing means.

[Action of the invention]

In the butterfly valve of the present invention, the biasing action applied to the second elastic sealing means from the elastic biasing means constituted by a spring through the cylindrical pusher plug causes a biasing action to be applied to the first annular sealing surface. The two annular sealing surfaces are elastically pressed. Therefore, the first annular sealing surface and the second annular sealing surface are brought into close enough contact with each other, and thus a sufficient seal is achieved between them, and the particulates contained in the flowing liquid are transferred between them. It is possible to reliably avoid problems such as intrusion. Compared to a coil spring, the disc spring constituting the elastic biasing means can have a sufficiently small elastic effective extension and contraction length and can exert a sufficiently large elastic biasing action. The valve can be assembled and disassembled sufficiently easily and quickly.

[Preferred specific examples of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings, and from the description, those skilled in the art will understand the above-mentioned features and advantages as well as other excellent aspects of the present invention.

In the following description, the same reference numerals are used throughout the description and drawings to refer to the same parts. The drawings are not necessarily to scale, and features of the invention may be illustrated, exaggerated for clarity and conciseness.

Referring primarily to FIGS. 1 and 2, there is illustrated a valve, generally designated by the reference numeral 10, in accordance with the present invention. The valve 10 is a so-called butterfly valve and is characterized by a cylindrical body 12 made up of opposed semi-cylindrical body parts 14 and 16, which are connected to each other along diametrical surfaces 15 and 17 by opposed fasteners 18. be done. Body portions 14 and 16 include opposing bosses 19 and 20, respectively, for receiving fasteners 18. Additionally, body portions 14 and 16 have opposing bosses 22 and 24, respectively. As shown in FIG. 2, the boss 22 includes stepped holes 26-28 and the boss 24
includes stepped holes 30-32. Additionally, housing portions 14 and 16 are provided with opposing semi-cylindrical flanges 34, 36, 38 and 40, respectively, for securing the valve between the flanges of a suitable conduit or the like (not shown).

Valve 10 further features a generally cylindrical butterfly-shaped closure disc 42 which is connected to longitudinal flow path 41.
PFA fluoroplastics of the type that are intercalated with and manufactured as Teflon®,
It is coated or overmolded with a continuous layer 44 of UHMPE or other plastic. Closing disk 42 includes opposing coaxial stem portions 46 and 48 that extend into bores 30, 32 and 26, 28, respectively. Each of the stem portions 46 and 48 has a cylindrical recess undercut at the locations indicated by numerals 47 and 49, respectively, in FIG. As will be apparent, the first elastic sealing means (constituting the first resilient sealing means) are extended. Stem portion 48 extends through bore 26 and is supported therein by spaced apart sleeve support members 54, which may be selected from self-lubricating and corrosion resistant materials. The stem portion 48 is
A drive projection 55 is provided for connection to a suitable drive mechanism for rotating the closure disc 42 about the central longitudinal axis of the stem portions 46 and 48. Cover 53 is suitably secured to boss 22 and includes a recess for an O-ring seal 57 disposed around stem portion 48, which seals against the stem portion and bearing 54 and mounting plate. engaged to prevent contaminants from leaking into the valve 10 from the surrounding environment. Stem part 46
is supported by a self-lubricating sleeve bearing 51 similar to bearing 54 and disposed within hole 30 .

Continuing the explanation with reference to Figures 1 and 2,
Stem portions 46 and 48 project from generally cylindrical bosses 58 and 60. The bosses 58 and 60 are covered with a PFA plastic layer (first elastic sealing means) 44, and are formed with annular sealing surfaces (first annular sealing surfaces) 59 and 61 facing outward in the stem axis direction. ing. The annular seal surfaces 59 and 61 are brought into close contact with annular seal surfaces (second annular seal surfaces) 62 and 64, respectively. The annular sealing surfaces 62 and 64 are formed in a generally cylindrical plastic liner (second resilient sealing means) generally designated by the numeral 66. The plastic liner 66 is attached to the outer peripheral flange 6 on both sides.
The body portions 14 and 16 are retained by positioning the body portions 14 and 16 between 8 and 70. Liner 66 is preferably high density
Preferably, it is integrally formed of PTFE fluoroplastic or UHMPE and includes opposing cylindrical collar portions 72 and 74 disposed about peripheral seal collar portions 50 and 52. As shown in FIG. 1, the liner 66 also includes opposing partial circumferential elastic support bands 78 and 80 interposed between the body portions 14, 16 and the liner 66. bands 78 and 80
upon engagement, allows a slight displacement of the liner peripheral wall 81 by the periphery of the closure disc 42, forming a fluid-tight seal between the closure disc and the seating surface formed by the wall 81. and reduces the detachment force required to rotate the closure disc away from the closed seating position into engagement with the wall 81. As shown in FIG. 2, the peripheral wall portion 81 extends along the longitudinal central axis A of the valve body liner 66.
(FIG. 1) radially outwardly at reference numerals 82 and 83, respectively, to the flanges 70 and 6.
Tilt in the direction of 8. Annular sealing areas are provided between the closure disc 42 and the liner 66 at associated sealing surfaces 59 and 62 and 61 and 64, respectively, thereby defining the area defined by the closure disc stem portions 46 and 48 and the liner peripheral wall 81. Provides a liquid-tight seal between the inner hole and the inner hole. This particular seal arrangement minimizes the chance of entrainment of debris or material entrained in the fluid flowing past the valve.
This is because, as the fluid flows around the closed disk 42, there are no pockets or circulation dead spaces where entrained material can stagnate.

Still referring to FIG. 2, valve 10 is provided with improved stem portion sealing means for stem portions 46 and 48, respectively. Stem part 46
Approximately cylindrical annular pusher plug 90
, the plug is at least partially located in the hole 3.
2 and has a lateral end surface capable of engaging liner 66 on the opposite side of sealing surface 62 to biasly engage sealing surface 62 with respect to sealing surface 59 . The pusher plug 90 has a countersunk hole 93 and a collar portion 7.
2 and forms a seal for the O-ring 94. The pusher plug 90 is biased toward the sealing surface 62 by the arrangement of back-to-back disk springs 96 interposed between opposing cylindrical seal washers 98 . A third seal washer 9 that can engage the seal cylinder 100 with one of the seal washers 98 and the pusher plug 90
8 around the stem portion 46. The arrangement of seal washer 98 and seal ring 100 provides a multi-purpose seal between pusher plug 90 and the distal end of stem portion 46, with the outermost seal washer 98 being able to protect the surrounding environment of the seal assembly of stem portion 46. Prevent exposure to contaminants. This arrangement is particularly advantageous in that the hole 30 can be opened to the outside air. Hole 30 may be closed by closure plug 101 to further reduce exposure of the seal assembly in hole 32 to the surrounding environment.

In accordance with an important feature of the present invention, the provision of a disc spring within the bore 32 provides a relatively high spring rate to urge the pusher plug 90 against the liner 66, creating a substantially liquid-tight seal in the annular cylinder. spring 96 with minimal linear movement as stem portion 46 and associated pusher plug 90 and sealing members 98 and 100 are withdrawn from bore 32 during disassembly and use of valve 10. This relaxation facilitates assembly and disassembly of the valve 10.

Additionally, stem portion 48 is provided with a seal structure substantially similar to the seal formed around stem portion 46. Connect the second pusher plug 90 to the collar portion 7.
4, and the O-ring 94 is placed around the lateral end surface 7 of the pusher plug 90 in the collar portion 74.
5 and a sealing surface 52 formed on the stem portion 48. A second back-to-back structure consisting of four circular discs or veribill type springs 96 is interposed in the hole 28 between the seal washers 98, and a seal ring 100 is attached to one seal washer 98 and a third seal washer 98 in contact with the pusher plug 90. Interpose between. Again, the relatively large spring force provided by the small deflection due to the arrangement of disc spring 96 applies a significant bias force to sealing surfaces 61 and 64 to form a fluid-tight seal therebetween while simultaneously Facilitates assembly and disassembly of seal parts. Seal washer 98 and seal ring 100 are preferably dimensioned to fit in close proximity around stem portions 46 and 48 in a substantially line-to-line relationship.
The arrangement of seal washer 98 and seal ring 100 protects seal bias spring 96 from exposure to corrosive fluids resulting from both internal and external environmental effects of valve 10.

According to another important aspect of the invention, overmolded or coated perfluoroalkoxy (PFA)
By providing the plastic layer 44 and by providing the high density polytetrafluoroethylene (PTFE) plastic liner 66, it has been determined that the closure disc has little tendency to stick to the liner in the closed and seated condition. Ta. Furthermore, with the same plastics of the PFA type provided as coating and liner material for the closure disc, it has been determined that over time there is a tendency for fusion to occur between these two parts. However, the use of PTFE and PEA plastics for each component maintains a suitably low coefficient of friction, reducing the opening torque of the closing disc and maintaining an adequate seal between the closing disc and the liner. and the above fusion tendency is removed. Additionally, layer 44 can desirably be formed from a molded polyvinylidene fluoride (PVDF) plastic, which has also been found to reduce the chance of cold fusion to the liner while providing a suitable coefficient of friction.

Referring now to Figure 3, generally reference numeral 11
A first variant of the butterfly valve according to the invention, designated 0, is shown. This valve 110 is identical in all respects to valve 10, except that the lower stem portion of the closure disc and the body portion 16 have been modified. In the valve 110, a closure disc 11 with a modified lower stem boss 114 having a lateral diameter blind hole 116 formed therein.
2 is provided. PEA on closed disc 112
Alternatively, a layer 118 of PVDF-type plastic may be overmolded, and this layer may cover the shortened lower stem portion 112.
It enters an undercut groove 120 formed above. In addition, sheath 118 forms an annular lateral sealing surface 123 that can engage sealing surface 62 on liner 66 . Valve 110 includes a lower body portion 124 similar to body portion 16, but with a bore 126 in which a trunnion 128 is suitably positioned, such as by a modified force fit. The trunnion 128 has a reduced diameter portion 129 that projects into the bore 116 in a supporting relationship with the lower stem portion 122 of the closure disc 112.

Additionally, valve 110 is provided with the improved sealing structure of the present invention, which includes sealing surface 62 of liner 66.
and the arrangement of the seal washer 98, a pusher plug 90, a seal ring 100,
It comprises a series of four back-to-back circular disk or Veribill type springs 96. In the valve 110 configuration, the closure disc 112 can be easily removed from the hole formed by the collar 72 of the liner 66 without the need to reinsert the stem portion 122 into the seal ring and circular disc spring. Further, the valve 110 can be used in applications where the stem portion seal must not leak even if the primary and secondary seal structures are damaged.

Referring now to FIG. 4, a second variation of the butterfly valve is shown generally by the reference numeral 140 in partial cross-section. This valve 140 is also the same as valve 10 but has a modified body liner 1 similar to liner 66 except that seal collar 72 has been removed.
42 is provided. Valve 140 also uses a modified body portion 144 in place of body portion 16, which
6, but with a blind hole 14 formed inside.
5 to accommodate the seal washer 98 and circular disc spring 96 assembly. A pusher plug 90 is also disposed within the hole 145 and seals the sealing surface 1.
47 and engages liner 142 adjacent to liner 47 .

A modified closure disc 150 is provided on valve 140, which is also similar to closure disc 42, except that boss 152 is provided in place of boss 58 and does not have an integral diametrically extending stem portion. The closure of the disk boss 152 is made of layer 1 of PFA plastic.
A lateral surface 155 is overmolded at 54 to form a sealing surface 155 that can engage sealing surface 147 .

Valve 140 is a typical design used for small diameter conduits such that a single stem portion, generally similar to stem portion 48, may be used to support closure disk 150 to the valve body. At the valve 140,
Body portion 14 may be used in conjunction with body portion 144 and closure disc 150 may include a stem portion (not shown) that is substantially similar to stem portion 48 of closure disc 42. Valve 140 reduces the risk of fluid leaking through the seal formed by sealing surfaces 147 and 155 and out of the body portion. This is because only one stem portion is present and potentially exposed to leakage from the valve itself. Additionally, the cavity formed by hole 145 is sealed from exposure to fluid flowing through the valve, in fact sealing rings 98 and 100 may be eliminated and spacers substituted or the depth of hole 145 reduced. The length can also be shortened so that spring 96 directly abuts pusher plug 90 and maintains a seal against surfaces 147 and 155.

Although specific embodiments have been described, those skilled in the art will recognize that many other modifications may be made without departing from the spirit and scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a partially sectional perspective view of a butterfly valve according to the present invention. FIG. 2 is an enlarged central longitudinal sectional view of the valve shown in FIG. 1, showing in detail the stem seal structure of the stem portion on the opposite side of the closure disc; FIG. 3 is a detailed cross-sectional view showing a modified closure disc pivot pin opposite the actuating stem portion or a variation in the seal arrangement for the stem portion; FIG. 4 is a detailed sectional view of a second variant of the closure disc seal arrangement on the side of the closure disc opposite the working stem portion; 10... Valve, 12, 14, 16... Body, 2
2, 24... Boss, 26, 28... Hole, 42...
...disk.

Claims (1)

[Scope of Claims] 1. A main body in which at least one stem portion accommodating hole extending in the stem axial direction is formed, and at least one stem portion extending in the stem axial direction being formed in the accommodating hole. a closing disk inserted into the main body and supported by the main body so as to be movable between an open position and a closed position; a first resilient sealing means having a first annular sealing surface facing outward in the direction; a second elastic sealing means extending annularly and having a second annular sealing surface facing inward in the axial direction of the stem and opposing the first annular sealing surface; and the second elastic sealing means. within the receiving hole and around the stem for elastically biasing the second annular sealing surface inward in the axial direction of the stem to elastically press the second annular sealing surface against the first annular sealing surface. an elastic biasing means configured of at least one disc spring disposed, and movable in the stem axial direction between the second elastic sealing means and the elastic biasing means and around the stem portion; a cylindrical pusher plug disposed in the elastic biasing means for transmitting the elastic biasing force of the elastic biasing means to the second elastic sealing means. 2. The second elastic seal means has a hole into which the stem portion is inserted, and an annular portion extending annularly around the hole, and the inner surface of the annular portion in the axial direction of the stem is the second annular seal. 2. A butterfly valve according to claim 1, wherein the butterfly valve defines a surface and wherein the resilient biasing means resiliently biases the annular portion in the direction of the axis of the stem. 3. The butterfly valve according to claim 1 or 2, wherein the disc spring constituting the elastic biasing means is disposed between a pair of seal washers. 4. One of the first elastic sealing means and the second elastic sealing means is made of high-density polytetrafluoroethylene, and the other is made of perfluoroalkoxy or polyvinylidene fluoride. The butterfly valve according to any one of items 3 to 3.