JPH0528549U - Oval valve box - Google Patents

Abstract

(57) [Summary] [Object] To obtain a spherical valve valve box having an S-shaped flow path formed by a central shoji portion and having no casting defects around the sliding screen portion. [Structure] When manufacturing a target valve valve box by a reduced pressure casting method, a sprue opening was formed in a substantially central portion of the valve box, that is, a central shoji portion. It is preferable that the valve box and the sprue opening are connected via a pedestal. At this time, the final product is a target valve valve box with the pedestal remaining.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a globular valve box manufactured by a reduced pressure casting method in which a breathable mold is used as a molten metal filter.

[0002]

[Prior Art]

 The structure of the globular valve box is, for example, as disclosed in Japanese Examined Patent Publication No. Sho 52-9849, it has connection openings at both ends for connecting pipes and a connection opening for mounting a valve lid at the upper part. Has a so-called shoji part that separates the lower fluid chamber from the upper fluid chamber. Therefore, the globular valve box has a shoji part that forms an S-shaped flow path in this way. By the way, this seed valve box is manufactured by casting.However, this casting method requires that the gate opening should be cut off in the horizontal or vertical direction due to the economics of core and mold manufacturing. Since the surface is limited to the position of the surface of the valve box, the sprue opening is usually provided in the mold cavity that contacts the parting surface. That is, the position was as shown in FIG.

[0003]

[Problems to be solved by the device]

 According to this manufacturing method, the directional solidification of the globular valve box from pouring to solidification is not performed in order from the center of the casting opening to the spout opening, especially in the center shown in Fig. 3. Since the shoji part 33 has a change in wall thickness and becomes thin, solidification of the molten metal progresses before other parts, and internal defects due to shrinkage occur. In addition, there was a globular valve in which fluid leaked from this part after processing and assembly due to manufacturing variations. The object of the present invention is to eliminate the above-mentioned conventional drawbacks and to provide a globular valve box without casting defects.

[0004]

[Means for solving the problem]

 The present invention has a horizontal dividing surface, in which at least one gate opening extending from the mold cavity is provided in the lower portion of the mold, and the mold cavity is formed by a reduced pressure casting method into a globular valve box. In the casting as described above, a sprue valve valve box is characterized in that a sprue opening is provided at substantially the center of the ball valve valve box forming an S-shaped flow path. A seat may be provided at the connecting portion between the spout opening and the globular valve box, and the spout opening may be provided on the opposite side of the valve box or at another end at another spout opening.

[0005]

[Action]

 The present invention is to manufacture an air permeable mold as shown in FIG. 4 and manufacture the globular valve box shown in FIG. 1 by the reduced pressure casting method. Since the sprue opening is provided in the shoji part that is prone to casting defects in the ball valve box, the molten metal is uniformly solidified as a result.

[0006]

【Example】

 The present invention will be described below based on embodiments. FIG. 1 is a side view of a spherical valve box 1 (hereinafter referred to as a valve box) showing an embodiment of the present invention. In the figure, the sprue opening 11 is a valve box made of a coarse cast material in which a part of the sprue opening 11 is cut out to a portion slightly higher than the casting indication of the spout and the root of the sprue opening 11 is slightly left. When the outer surface of the valve box and the root of the sprue opening are connected to each other with a pin angle, the shape of the pedestal 12 suddenly changes and shrinkage cavities or the like occur here. Therefore, the sprue is connected with a large radius through this pedestal. Here, there is no need to provide a pedestal when there may be a trace of radius on the outer surface of the valve box.

FIG. 3 is a vertical cross-sectional view of the valve box, which is a cross section perpendicular to the parting plane. There is an S-shaped shoji part connected by an upper shoji part 31 and a lower shoji part 32, and the spout opening 11 is formed on the outer surface of the central shoji part. The shape of the sprue opening 11 is appropriately determined mainly depending on the distance between the upper shoji part 31 and the lower shoji part 32. Normally, if the volume of the shoji part is large, it is necessary to increase the cross-sectional area of the spout opening. Considering the directional solidification of the valve box 1 from the same horizontal plane, the position of the sprue opening is the point of the upper and lower shoji parts 31, 32 of the valve box 1, and the flow path is the center of the S-shape. It is also the position. That is, it is the position of the central shoji part 33.

Next, a manufacturing method will be described with reference to FIG. FIG. 4 is a schematic view of a vacuum casting device. The upper mold 41 and the lower mold 51 are combined through a core to form the mold cavity portion 5 that serves as a valve box. Then, this is held by the mold pouring machine 61, immersed in the molten metal 63 in the high-frequency furnace 64, the pressure in the decompression chamber 62 is reduced, the molten metal is sucked up from the spout opening 11 and poured into the cavity to manufacture a casting. ing.

In the above manufacturing process, when the molten metal 63 completely fills the mold cavity portion 5 in the solidification process of the molten metal, cooling starts from the molten metal portion in contact with the mold and the core and solidification of the molten metal occurs. As a large heat source, the temperature gradient of the molten metal in the mold becomes higher in the lower mold 51 than in the upper mold 41, and the central shoji part of the lower mold 51 is connected to the molten metal 63 until the end. Therefore, the mold cavity 5 is directionally solidified in the order from the upper mold 41 to the lower mold 51, the molten metal is sequentially supplied, and the lower shoji part 32 is finally solidified. Immediately, at the end, the molten metal does not reach the central shoji part and defects such as shrinkage cavities do not occur.

By the way, the solidification sequence of each part of the casting can be known by calculating and comparing the ratio Sa / V of the surface area Sa to the volume V of each part. According to this definition, the present inventor has tried coagulation simulation for valve boxes of various sizes. As a result, it was confirmed that the shoji part having a large Sa / V ratio had relatively fast coagulation. Then, it was confirmed that by providing the sprue opening at this portion as described above, the molten metal disappeared to the end without sudden defects. Further, by providing another sprue opening on the opposite side of the valve box as shown in FIG. 5, and further by providing second and third sprue openings on both sides as shown in FIG. It was confirmed that the bathing area improved and good results were obtained.

[0011]

[Effect of the device]

 According to the present invention, it is possible to obtain a ball valve box that does not have a casting defect in the shoji part.

[Brief description of drawings]

FIG. 1 is a side view of a target valve element according to an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional plan.

FIG. 3 is a sectional view of the front view of FIG.

FIG. 4 is a view showing an apparatus and a mold cross-sectional view of one embodiment of the manufacturing shown in FIG.

FIG. 5 is a view of a target valve valve box showing another embodiment of the present invention.

FIG. 6 is a view of a target valve valve box showing another embodiment of the present invention.

[Explanation of symbols]

 1 Ball valve box 5 Mold cavity 11, 21, 71, 72, 73, 74 Gate opening 12 Pedestal 22 Shrinker 31, 32, 33 Shoji part 41, 51 Mold 61 Mold thrower 62 Decompression chamber 63 Molten metal 64 High frequency furnace

Claims (4)

[Scope of utility model registration request] 1. A horizontal valve-shaped valve valve box having a dividing surface, at least one gate opening extending from the mold cavity in the dividing surface is provided in the lower part of the mold, and the mold cavity is formed by a vacuum casting method. In the casting, the globular valve valve box is characterized in that a sprue opening is provided substantially in the center of the globular valve valve box forming an S-shaped flow path. 2. In the claim of utility model claim 1,
A ball valve valve box characterized in that a seat is provided at a connecting portion between the gate opening and the ball valve valve box. 3. In claim 1 of the utility model claim,
A globular valve box characterized in that another gate opening is provided on the opposite side of the gate opening. 4. In claim 1 of the utility model,
A globular valve box, characterized in that second and third gate openings are provided on both sides of the gate opening.