JPS5937371A - Butterfly valve and its manufacturing method - Google Patents

Abstract

PURPOSE:To provide a butterfly valve with sufficient function of stopping the water, by embedding its valve seat made in anti-corrosive metal in the valve chest or body of cast iron or steel, in such a way that only the contact surfaces are exposed, by jointing the seat with the body firmly by means of dovetails and of unevened surfaces, and thereby securely fixing the seat to the chest and body. CONSTITUTION:This valve chest 1, has such a construction that a pair of semi- circular valve seats 3 made in anti-corrosive metal such as stainless steel are embedded in the body 2 of cast iron or steel. The valve seats 3 are equipped at their inside surfaces with contact face for valve element, at its outside surfaces with unevened surfaces for engagement with the body 1, and with sides 3c, 3d to form dovetails. Butterfly valve has such a construction that its valve element in a similar arrangement to the above-mentioned valve chest is installed on the chest by means of the valve stem, and the seat is jointed to the chest body and to the valve element's body solidly by means of dovetails and unevened surfaces. Accordingly there is no risk of distortion at the contact faces of valve chest and the seat of valve element to assure satisfactory function of stopping the water.

Description

[Detailed description of the invention] The present invention relates to a butterfly valve and a method for manufacturing the same.

Conventional butterfly valves use corrosion-resistant metal materials for the valve seat.
By fitting a valve seat made of a corrosion-resistant metal material to the valve body or valve body, and fixing the valve body or valve body and the valve seat with a retaining ring, screw, welding, or other means. It was manufactured.

However, conventional butterfly valves manufactured in this way have a complicated manufacturing process and are not suitable for mass production, and also have the disadvantage that a gap is created between the valve body or valve body body and the valve seat, which deteriorates the water shutoff function. there were. Regarding valve bodies, there is a conventional technology in which only the mounting surface of the valve seat is cast when the valve body is cast, but when the valve body is cast, a part of the valve seat extends outside the valve body. Therefore, during casting, the valve seat undergoes severe deformation due to temperature distribution, and cracks also occur at the boundary between the valve body and the valve seat, resulting in incomplete water-stopping function.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a butterfly valve whose valve seat is securely fixed to the valve box body and the valve body body, the city water function is complete, and which is highly suitable for mass production, and a method for manufacturing the same. With the goal.

Embodiments of the present invention will be described below based on the drawings. 1 and 2 are cross-sectional views illustrating a valve box 1 according to the present invention. A valve box 1 has a pair of semicircular valve seats 3 made of a corrosion-resistant metal material such as stainless steel embedded in a valve box main body 2 made of cast iron or cast steel. The valve seat 3 has a contact surface 3α between the valve body and the valve seat on the inner circumferential surface, and an uneven surface 3b to be connected to the valve body body 1 in a meshing state on the outer circumferential surface, or a notch or notch in place of this. , the side 3c that forms the ant.

Equipped with 3d. The contact surface 3α of the valve seat 3 is exposed to the inner space of the valve body body 2, but the other surfaces, that is, the uneven surface 3b and the side surfaces 3c and 3d are buried within the valve body body 2. Further, a ring-shaped member 4 is sandwiched between the pair of valve seats 3, and a valve shaft hole 5 is provided passing through the ring-shaped member 4 and the valve body body 2.

3 to 6 are cross-sectional views illustrating the steps of the method of the present invention for manufacturing the above-mentioned valve body. To manufacture it, prepare the Oz valve seat material 3R. The valve seat material 3R is a pair of semicircular rings made of a corrosion-resistant metal material such as stainless steel, and has an uneven surface 3b to form the valve seat in the finished valve box shown in FIGS. 1 and 2. and side surfaces 3c and 3a, the inner peripheral surface 3e of which has an inner diameter that takes into account the cutting allowance for cutting and machining that will be performed later. The valve seat material 3R is its inner peripheral surface 3
A large number of support rods 6 are installed in the radial direction from e. Next, a mold 7 as shown in FIGS. 3 and 4 for casting the valve body body is prepared. The mold 7 includes a main core 8 that holds the valve seat material 3R in a state in which the support rods 6 of the valve seat material 3 manufactured as described above are fitted, and a ring-shaped member 4 that is attached to a pair of valve seat materials 3.
The upper mold 12 and the lower mold 1 are formed by the valve stem hole core 9, the main core 10, and the lower core 11 held so as to be positioned between R.
A mold space 14 for the valve body body is provided between the three spaces. A sufficient distance L1 is provided between the inner circumferential surface 3e of the valve seat material 3R and the main core 8 so that a temperature distribution exceeding a predetermined range does not occur in the valve seat material 3R during casting of the valve body body. . Further, a gap L2 is provided between the uneven surface 3b of the valve seat material 3R and the upper mold 12 and the lower mold 13. Therefore, the pair of valve seat materials 3R are held in a floating state within the core mold space 14. Hot water is poured into the mold space 14 of the mold 7 prepared in this way through the sprue 15, runner 16 and weir 17.

Note that 18 is a riser.

When the mold is released after waiting for the hot water to cool and solidify, the entire valve seat material 3R is cast into the valve body material 2R made of cast iron or cast steel and formed into a support rod, as shown in FIGS. 5 and 6. A state in which 6 stands out is obtained.

Next, the valve box main body material 2R and the valve seat material 3R are cut along the imaginary line in FIG. 6 to form the contact surface 3α so as to be exposed inward of the valve case main body 2. After finishing the shaft hole 5 and the like, the valve box 1 shown in FIGS. 1 and 2 is completed.

Although the valve body 1 of the butterfly valve and the manufacturing method thereof according to the present invention have been described above based on the illustrated embodiment, it goes without saying that the valve body of the butterfly valve can be manufactured using the same procedure. A butterfly valve is obtained by attaching the valve body to the valve body manufactured in this manner using a valve stem.

Next, the effects of the present invention will be described. In the butterfly valve of the present invention, only the contact surface of the valve seat is exposed and it is buried in the valve body or valve body, so the valve seat made of an expensive corrosion-resistant material can be made as small as possible. The valve seat can be securely fixed to the valve body or the valve body even if the valve body is attached to the valve body or the valve body. Moreover, the valve seat and the valve body body or the valve body body are firmly connected to each other by the dovetail and uneven surface. Therefore, the shapes of the contact surfaces provided on the valve body and the valve seat of the valve body are not distorted, and a sufficient water-stopping function can be exhibited. Furthermore, for the same reason, water leakage from between the valve seat and the valve body body or the valve body body can be sufficiently prevented.

If the butterfly valve according to the present invention is manufactured by the method of the present invention, the above-mentioned water shutoff function will be even more remarkable. In other words, when the valve body or valve body is cast, the entire valve seat is wrapped around the valve body or the valve body, so it is later cut to expose the desired contact surface. It is not affected by temperature changes during casting. In addition, the valve seat made of stainless steel or other material with a high coefficient of thermal expansion has a higher shrinkage rate than the valve body or valve body when cooled, so the uneven surface of the valve seat can be made to bite into the valve body or the valve body. Join.

Therefore, the space between the valve seat and the valve body body or the valve body body is maintained watertight, and the water-stopping function can be improved.

Furthermore, in the manufacturing method according to the present invention, it is sufficient to prepare a mold so as to hold the valve seat material and the ring-shaped member in a floating state in the mold space, and perform the desired processing such as cutting after casting. It can be adapted to mass production.

As described above, the present invention has a high water-stop function and is excellent in the effect of being able to adjust the dose.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a cross-sectional view of a valve box, FIG. 2 is a cross-sectional view taken along line II-11 of FIG. 1, and FIG. 3 is a longitudinal sectional view of a mold used for manufacturing the valve box. , Figure 4 is I of Figure 3.
V-TV cross-sectional view, Figure 5 is a cross-sectional view showing the state of the valve body directly released from the mold cast with the mold shown in Figure 3, and Figure 6 is the
It is a Vl-Vl sectional view of the figure. 1... Valve box 2... Valve box body 3... Valve seat 3α... Collision surface 3b... Uneven surface 7... Mold patent applicant Meiwa Kiso Co., Ltd. 38 1 n Go 1

Claims (2)

[Claims] (1) A valve seat made of a corrosion-resistant metal material is attached to the cast iron or cast steel valve body and valve body of the butterfly valve, and almost the entire surface other than the contact surface of the valve seat is attached to the valve body or the valve body. buried in 5i
1. A butterfly valve, characterized in that the valve seat is buried in such a manner that an uneven surface and a dovetail are formed on at least a part of the buried surface of the valve seat. (2) The valve body and the valve seat of the valve body are formed with an uneven surface and a dovetail on at least a part of the surfaces other than the contact surface, and then the entire valve seat is cast with cast iron or A valve body and a valve body made of baked steel are cast, and then the valve body and the valve body are cut to expose the contact surface of the valve seat to form the valve body and the valve body. A method for manufacturing a butterfly valve, which comprises assembling a valve box and a valve body with a valve shaft to form a butterfly valve.