JP5886672B2 - Seal structure of valve box division - Google Patents

Description

  The present invention relates to a seal structure of a valve box division part such as a bi-leaf valve or an eccentric butterfly valve having a split valve box.

Conventionally, a double leaf valve has been used as an inlet valve for a water turbine in a hydroelectric power plant.
The valve body of the double leaf valve is formed by connecting two flat plates in parallel with vertical ribs, and has a small loss factor when the flow path is fully opened. Therefore, if it is used as an inlet valve for a turbine, hydraulic loss can be kept low.

  Among such multi-leaf valves, in particular, those having a large diameter and used for a medium drop have a structure in which a valve box can be divided into two on the surface along the axial direction of the flow path (for example, Patent Document 1 ( (See FIG. 16)).

  The double leaf valve V ′ shown in FIG. 4 also has a structure in which the valve box can be divided into two parts, and is conventionally used. The valve box 1 has a structure that is divided into two in the vertical direction, with a plane orthogonal to the axial direction of the valve stem 4 and extending along the axial direction of the flow path 3 as a split plane (hereinafter referred to as split plane).

  A groove 6 for fitting a water-stopping packing is carved on the split surface 11 of the lower part of the divided valve box. After the packing is fitted in the groove, the split surface 11 'of the upper part of the valve box is assembled to assemble the valve box, thereby preventing water leakage from the part (valve box split part) where the split faces are combined.

  FIG. 5 is a cross-sectional view of the split surface of the conventional bi-leaflet valve V ′, and the packing groove 6 is perpendicular to the groove straight part 61 extending straight along the axial direction of the flow path 3 and the groove straight part. Thus, the groove branch part 62 branched from the groove straight part is formed in an integrally carved shape.

6A shows an enlarged view of the split surface portion shown in FIG. 5, and FIG. 6B shows a packing 7 used in the bi-leaflet valve V ′.
The packing 7 is formed in a shape that follows the groove so as to fit into the groove 6. That is, a packing straight part 71 having a shape that follows the groove straight part 61 and a packing branch part 72 having a shape that follows the groove branch part 62 are integrally formed, and the packing straight part 71 and the packing branch part 72 are integrally formed. It fits into the groove straight part 61 and the groove branch part 62.

With the packing 7 fitted in the groove 6, when the split faces are aligned and the valve box is integrated, the split faces become liquid-tight via the packing direct part 71, and water leaks from the part where the split faces are combined. To prevent that.
Further, as shown in FIG. 5, when the valve body 2 is set to the fully closed position after the valve box is assembled, the tip of the packing branch 72 appearing on the surface of the valve seat 8 and the valve body sheet 21 come into contact with each other. And become liquid-tight. This prevents water from leaking from the upstream side to the downstream side of the valve body 2 through the portion where the split surfaces are combined.

JP-A-63-158367

However, in such a conventional valve box split part seal structure, the tips of the split surface grooves (both ends of the groove straight part and the tip of the groove branch part) are open. The tips (both ends of the packing direct portion and the tips of the packing branches) may gradually protrude from the opening at the tip of the groove.
It is difficult to push the packing once protruding into the groove, and it is necessary to cut the protruding portion or, depending on the case, to disassemble the assembled valve box and reset the packing.
Such reworking significantly hinders productivity.

  An object of the present invention is to provide a seal structure that does not hinder productivity in the assembly work of a valve box.

  In order to solve the above-mentioned problems, the seal structure of the valve box split part of the present invention is a seal structure of the valve box split part of the butterfly valve that can be divided into the valve box, and the valve box is along the axial direction of the flow path. The groove can be divided by a split surface, and a groove for fitting a water-stopping packing is provided on the split surface. The groove includes a straight groove straight portion along the axial direction of the flow path, and a groove straight portion. A groove branch portion that branches from the valve seat and extends toward the surface of the valve seat, and an end portion of the groove is provided with a locking portion having a contact surface facing the opposite side to the tip direction of the end portion, When the valve box is assembled by combining the split surfaces, the packing fitted in the groove hits the contact surface.

  This prevents the packing from being compressed in the thickness direction and extending in the longitudinal direction when the valve box split part is assembled with the split surfaces, so that the locking part suppresses the packing after the valve box is assembled. It is possible to prevent it from protruding from the opening at the end.

  Further, in the seal structure of the valve box division part of the present invention, the locking part is a recess carved in a direction orthogonal to the groove, and a protrusion bulging in the direction orthogonal to the longitudinal direction is provided on the packing, When the packing is fitted into the groove, the projection can be fitted into the recess.

  Further, in the seal structure of the valve box split portion of the present invention, the locking portion is a wall portion that crosses the groove, and the contact surface is the tip direction of the end portion of the side surface of the wall portion. A portion facing the opposite side may be configured such that when the packing is fitted into the groove, the tip of the packing faces the contact surface.

  Further, the seal structure of the valve box division part of the present invention is a seal structure of the valve box division part of the butterfly valve that can divide the valve box, and the valve box can be divided by a split surface along the axial direction of the flow path. The split surface is provided with a groove for fitting a water-stopping packing, and the groove includes a straight groove straight part along the axial direction of the flow path and a groove perpendicular to the groove straight part. It consists of a groove branch portion that branches off from the straight portion and extends toward the valve seat surface, and an end portion of the groove is provided with a locking portion having a contact surface facing the opposite side to the tip direction of the end portion, The engaging portion is a concave portion carved into the end portion of the groove straight portion in a direction perpendicular to the groove, and a wall portion crossing the end portion of the groove branch portion, and the contact surface is an inner surface of the concave portion. The side wall of the wall portion is swelled in a direction perpendicular to the longitudinal direction of the packing straight portion that follows the groove straight portion when the packing is fitted in the groove. When the packing straight part is fitted into the groove straight part, the protrusion fits into the concave part, and the packing branch follows the groove branch part when the packing is fitted into the groove. When the portion is fitted into the groove branch portion, the tip of the packing branch portion faces the side surface of the wall portion, and when the valve box is assembled by aligning the split surfaces, the fitting portion is fitted into the groove. It can be set as the structure where packing contacts the said contact surface.

  The seal structure of the valve box split part of the present invention prevents the end of the packing from protruding from the valve box split part, and it is necessary to cut the protruding part or to disassemble the valve box and set the seal packing again. Absent.

It is a cross-sectional view of the double leaf valve provided with the seal structure in the first embodiment of the present invention. It is a principal part enlarged view of FIG. 1, (a) shows a split surface, (b) shows packing. It is a principal part enlarged view of the double leaf valve provided with the seal structure in other embodiment of this invention, (a) shows a split surface, (b) shows packing. It is a front view of a double leaf valve. It is a cross-sectional view of a double leaf valve having a conventional seal structure. It is a principal part enlarged view of FIG. 5, (a) shows a split surface, (b) shows packing.

Based on FIG. 1 to FIG. 3, the seal structure of the valve box dividing portion in the embodiment of the present invention will be described.
FIG. 1 is a cross-sectional view of the bi-leaflet valve V in the first embodiment of the present invention, and shows a cross-section at the split surfaces 11 and 11. In this figure, the valve body 2 is in the fully closed position, and the valve body sheet 21 attached to the outer peripheral edge of the valve body 2 comes into contact with the surface of the valve seat 8 provided on the inner surface of the valve box 1, 3 is completely cut off.

The split surfaces 11, 11 of the valve box are in the same plane including the axis L of the flow path 3, and the valve box 1 has a structure that can be divided into two along the axial direction of the flow path 3.
A groove 12 for fitting a water-stop packing is carved on the split surface 11 of the valve box. The shape is a straight groove straight part 121 along the axial direction of the valve box 1 (the axial direction of the flow path 3), and a groove branch part that branches to be orthogonal to the groove straight part and extends to the surface of the valve seat 8. 122 is integrally carved with the same width and depth.

FIG. 2 is an enlarged view of the main part of FIG. 1, (a) shows the split surface 11, and (b) shows the packing 5.
The packing 5 is an elongated rubber rod-shaped sealing material having a circular cross section, and a packing straight part 51 that follows the groove straight part 121 and a packing branch part 52 that follows the groove branch part 122 are integrally formed so as to fit the groove 12. Has been.

  Near both ends (end portions) of the groove straight portion 121, recesses 13 that are orthogonal to the groove straight portion are formed by carving laterally on both side surfaces of the groove, and the end portions of the groove have a cross shape. Protrusions 53 that swell laterally from both side surfaces of the packing are attached near both ends of the packing direct part 51 so as to follow the cross shape. When the packing is fitted into the groove, the protrusion 53 is fitted into the recess 13 of the groove.

A wall portion 14 rising from the bottom surface of the groove is formed at the front end of the groove branch portion 122, and the vicinity (end portion) of the front end of the groove branch portion becomes shallower toward the front.
The position where the wall portion 14 intersects the split surface, that is, the tip position 16 of the groove branch portion 122 is a groove of a predetermined minute dimension from the flow path side periphery of the split surface (the portion where the inner surface of the valve seat 8 intersects the split surface) It is in a place near the straight part 61. That is, the tip position 16 of the groove 12 and the inner surface of the valve seat 8 are separated by a minute distance, and the groove branch portion stops at the wall portion 14 and does not open to the inner surface of the valve seat 8. (See C arrow view)

When the split surfaces 11 and 11 ′ are combined and the valve box 1 is assembled integrally, the packing 5 is sandwiched between the split surfaces and compressed in the thickness direction, and in the longitudinal direction (axial direction of the groove). extend.
In the vicinity of both ends of the groove straight part 121, the compressed packing extends in the longitudinal direction and tends to protrude from the opening of the groove end, but the packing protrusion 53 fitted in the recess 13 orthogonal to the groove straight part. However, when it hits the inner surface (contact surface 17a) of the recess, the elongation in the longitudinal direction is suppressed.

  Even in the vicinity of the tip of the groove branch portion 122, the compressed packing 5 extends in the longitudinal direction and tries to protrude outward from the tip of the groove. It is done.

  In this embodiment, the recessed portion 13 and the wall portion 14 serve as a locking portion having a surface (contact surface 17a, 17b) facing the side opposite to the tip of the groove.

FIG. 3 is an enlarged view of a main part of a bi-leaflet valve having a seal structure according to another embodiment, wherein (a) shows a split surface and (b) shows a packing.
A recess 15 perpendicular to the groove is vertically carved near both ends of the groove straight part 121 ′ and near the tip of the groove branch part 122 ′, and the end of the groove has a T-shape in a side view (E arrow) See the view).
Downward protrusions 53 ′ are provided near both ends of the packing direct part 51 ′ and near the tip of the packing branch part 52 ′ so that the packing 5 ′ fits into the recess 15.

When the split surfaces are put together and the valve box is assembled integrally, the packing 5 ′ is sandwiched between the split surfaces, compressed in the thickness direction, and extended in the longitudinal direction (axial direction of the groove).
The compressed packing extends in the longitudinal direction near the both ends of the groove straight part 121 ′ and the tip of the groove branch part 122 ′, and tries to protrude outward from the opening at the groove end, but is orthogonal to the groove straight part. The protrusion 53 ′ of the packing fitted in the recess 15 hits the inner surface (abutment surface 17 c) of the recess 15, and the elongation in the longitudinal direction is suppressed.
In this embodiment, the concave portion 15 serves as a locking portion having a surface (contact surface 17c) facing the side opposite to the tip of the groove.

  In each embodiment, the double-leaf valve box is taken up as a two-divided valve box. However, the double-valve valve box is not limited to the double-leaf valve (double-leaf type butterfly valve), and can be divided along the flow path. The present invention can be applied to any butterfly valve box.

1 Valve box
11 Split surface 6, 12 Groove 61, 121 Groove straight part 62, 122 Groove branch part 13, 15 Recess (locking part)
14 Wall (locking part)
16 Tip position 17 Contact surface 2 Valve element 22 Vertical rib 3 Flow path 4 Valve rod 5, 7 Packing 51, 71 Packing direct part 52, 72 Packing branch part 53 Packing protrusion 8 Valve seat V, V 'Double leaf valve (valve)
L axis

Claims (4)

A seal structure of a valve box division part of a butterfly valve in which the valve box can be divided,
The valve box can be divided at a split surface along the axial direction of the flow path,
A groove for fitting a water stop packing is provided on the split surface,
The groove comprises a straight groove straight portion along the axial direction of the flow path, and a groove branch portion that branches from the groove straight portion and extends toward the surface of the valve seat,
At the end of the groove, provided with a locking portion having a contact surface facing the opposite side to the tip direction of the end,
The seal structure of the valve box split part, wherein the packing fitted in the groove hits the contact surface when the valve box is assembled with the split surfaces aligned. The locking portion is a recess carved in a direction perpendicular to the groove,
Providing the packing with a protrusion that swells in a direction perpendicular to its longitudinal direction,
The seal structure of the valve box division part according to claim 1, wherein when the packing is fitted into the groove, the projection is fitted into the recess. The locking portion is a wall portion that crosses the groove, and the contact surface is a portion of the side surface of the wall portion that faces the side opposite to the tip direction of the end portion,
The seal structure of the valve box division part according to claim 1, wherein when the packing is fitted into the groove, the tip of the packing faces the contact surface. A seal structure of a valve box division part of a butterfly valve in which the valve box can be divided,
The valve box can be divided at a split surface along the axial direction of the flow path,
A groove for fitting a water stop packing is provided on the split surface,
The groove comprises a straight groove straight part along the axial direction of the flow path, and a groove branch part extending from the groove straight part and extending toward the valve seat surface so as to be orthogonal to the groove straight part,
At the end of the groove, provided with a locking portion having a contact surface facing the opposite side to the tip direction of the end,
The locking portion, a recess carved into the end of the straight portion of the groove in a direction perpendicular to the groove, and a wall portion crossing the end of the groove branch portion,
The contact surface is an inner surface of the concave portion and a side surface of the wall portion,
When the packing is fitted in the groove, the packing straight part that follows the groove straight part is provided with a protrusion that swells in a direction perpendicular to the longitudinal direction, and the packing straight part is fitted in the groove straight part. The protrusion fits into the recess,
When the packing branch part that follows the groove branch part when the packing is fitted into the groove is fitted into the groove branch part, the tip of the packing branch part faces the side surface of the wall part,
The seal structure of the valve box split part, wherein the packing fitted in the groove hits the contact surface when the valve box is assembled with the split surfaces aligned.