JPH0429165Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an eccentric butterfly valve, and particularly to an improvement of the seat ring of the valve.

[Prior Art] Synthetic resins, particularly fluororesins [typically Teflon (registered trade name, manufactured by DuPont)] are increasingly being used as seat rings for butterfly valves and ball valves. This fluororesin has high corrosion resistance, so it is used in the chemical industry that supplies chlorine gas, acetic acid, and other acids, and in the food industry (edible oil, seasonings, etc.) where metal ion penetration from parts that come in contact with fluids is a problem. As a result, extremely safe and long-lasting operation can be expected.

For example, as shown in FIG. 5, there is one in which a seat ring 14 made of a single fluororesin is attached to a valve box 11 via a retaining ring 15. Since the fluororesin in this case cannot be said to have much elasticity, attempts are being made to enhance the sealing force with the valve body 12 by modifying the shape. However, fluororesin is a fairly expensive material, and not only does it have problems with the reliability of complete sealing, but it is also difficult to process. Attached.

What was developed was a form in which the seat ring is constructed from a combination of composite materials.

FIG. 6 shows an example of this, and the seat ring 14 attached to the valve box 11 via the retaining ring 15 has a rubber elastic body 18 contained inside the fluororesin outer layer 17, and the valve body 12 rotates. When closing the flow path in the valve body 11, the wiper effect of the fluororesin causes the valve body 12 to close.
The elasticity of the contained elastic ring ensures a perfect seal under low pressure and vacuum.
When the pressure increases further, the fluororesin outer layer 17 containing the elastic ring deforms and strongly presses against the valve body 12 to maintain a complete seal.

FIG. 7 shows another example, in which numeral 14 is a seat ring attached to the valve body 11, and a valve body 12 is concentrically disposed within this seat ring via a valve shaft 13. Furthermore, this seat ring 14 has an elastic rubber 18 fitted inside the fluororesin lining 17.
Furthermore, a rigid ring 19 made of phenol resin is attached to the back of the valve body 11 as a support.

In this way, the fluororesin lining 17 is attached to the valve body 12.
In addition to the above-mentioned characteristics, the use of the material on the contact surface with the material has the advantage that the opening/closing torque is reduced.

[Problems to be solved by the invention] However, this advantage becomes a negative factor when it is combined with other substances to form a composite.

That is, there is a problem in that it is easy to slip between it and other constituent materials, and as a result, the composite is likely to come off.
In the case of FIG. 6, taking these points into consideration, the cross section of the fluororesin is formed into an irregular polygon so as to wrap around the elastic ring 18, but this makes processing and assembly complicated, and Adjusting the air gap to ensure sealing force due to elastic deformation also poses subtle difficulties.

Furthermore, in the case of FIG. 7, slips occur between the fluororesin layer 17 and the elastic rubber 18.

Therefore, the present invention was made to solve the above-mentioned problems, and the purpose is to provide an eccentric butterfly valve that has improved sealing performance and resistance to detachment. .

[Means for Solving the Problems] In order to achieve the above object, the eccentric butterfly valve of the present invention has a seat ring having an outer diameter smaller than the inner diameter of the recess of the valve body and a U-shaped cross section. It consists of a thin-walled fluororesin annular body having a shape, and an elastic ring and a rigid ring that are fitted in order into the U-shaped recess of the fluororesin thin-walled annular body, and on both sides of the fluororesin thin-walled annular body near the outer periphery. The formed protrusion or recess is engaged with the recess of the valve body and the recess or protrusion formed on the retainer ring.

[Operation] When the valve body is closed, the valve body presses against the fluororesin thin annular body, and this pressure deforms the built-in elastic ring, ensuring sealing.

In addition, the elastic ring and the rigid ring are fitted into the U-shaped recess of the thin-walled fluororesin annular body with a U-shaped cross section, and are tightly tightened by the rigid ring. This prevents leakage of fluid, even in the case of
Very little corrosion or deterioration.

Further, when the valve body is opened, the seat ring is engaged by the protrusions or recesses formed on both sides of the thin-walled fluororesin annular body near the outer periphery and the recesses or protrusions formed on the valve body and the retaining ring. Therefore, it will not escape from the valve body due to fluid pressure.

[Example] Embodiments of the present invention will be described with reference to the drawings.

In Figures 1 to 3, 1 is a valve body of an eccentric butterfly valve, 2 is a valve body disposed eccentrically within the valve body 1 by a valve shaft 3, and 4 is a valve body disposed on the outer periphery of the valve body 2. This seat ring is fixed to a recess 1a on one side of the valve body 1 with a bolt 6 via a presser ring 5.

The seat ring 4 has an outer diameter smaller than the inner diameter of the recess 1a of the valve body 1, and a thin annular body 7 made of fluororesin and having a U-shaped cross section, and an elastic ring 8 and a rigid ring 7 arranged in this U-shaped recess 7a. This is a composite structure in which the ring 9 is fitted.

The elastic ring 8 is made of an elastic body such as rubber,
Further, the rigid ring 9 is made of metal or a synthetic resin such as phenolic resin having some flexibility.

Further, the fluororesin annular body 7 has outward protrusions 7b formed on both sides near its outer periphery.

This protrusion 7b is engaged with the recess 1b formed in the recess 1a of the valve body 1 and the recess 5a of the retainer ring 5.

In Figure 3, the protrusion is formed into a mountain shape and provided with two stripes,
This protrusion 7c is engaged with the recess (groove) 1b of the valve body 1 and the recess (groove) 5b of the retainer ring 5. This chevron-shaped protrusion is not limited to the above two stripes.

FIG. 4 shows a recess (V groove) 7 in place of the protrusion 7c.
d, and protrusions 1c and 5 are provided in this groove 7d in place of the groove 1b of the valve body 1 and the groove 5b of the retaining ring 5.
c.

Furthermore, although not shown, the protrusion of the annular body 7 is omitted, and a mountain-shaped protrusion 5 as shown in FIG. It can also be engaged by biting into both sides.

Furthermore, it is important to form the protrusions and recesses (grooves) of the annular body 7 in the embodiment so as to be located outside the rigid ring 9 in order to securely fix the seat ring 4.

Further, the fluororesin annular body 7 is usually obtained by cutting a cylindrical material into a U-shaped cross section and then slicing it into rings, but it may also be directly molded using a mold. Further, the thickness of this annular body is 0.5 to 2.0 mm.

Next, the operation of the embodiment will be explained.

When the valve body 2 is in the closed position, the valve body presses the annular body 7 of the seat ring 4, and this pressing force deforms the elastic ring 8, thereby sealing the fluid.

In addition, the corrosive fluid is between the seat ring 4 and the valve body 1.
Or, even if fluid leaks between the presser rings 5, the elastic ring 8 and rigid ring 9 are covered by the fluororesin annular body 7, so that they will not come into direct contact with the fluid.

Further, the seat ring 4 is firmly clamped and fixed by the valve body 1 and the presser ring 5 at the rigid ring 9 portion.

[Effects of the Invention] Since the present invention is configured as described above, it has the following effects.

The seat ring consists of a thin fluororesin annular body whose outer diameter is smaller than the inner diameter of the recess of the valve body and a U-shaped cross section, and an elastic ring that is sequentially fitted into the U-shaped recess of the fluororesin thin annular body. a ring and a rigid ring, the protrusions or recesses formed on both sides of the thin-walled fluororesin annular body near the outer periphery are engaged with the recesses or protrusions formed on the recess of the valve body and the retaining ring. As a result, the seat ring can be easily assembled into the valve body, and the built-in elastic ring provides sealing performance.Furthermore, the engagement of the protrusion and the recess allows the seat ring to be attached to the valve body by fluid pressure. The rigid ring and the elastic ring 8 are reliably prevented from slipping out, and furthermore, the strong clamping provided by the rigid ring prevents leakage of the fluid even if the fluid is corrosive. Corrosion and deterioration are extremely small, making it durable for long-term use, and there is no risk of over-tightening of the elastic ring.

Furthermore, since the fluororesin thin-walled annular body has a simple U-shaped cross section, it is easy to mold and process, the manufacturing cost is low, and furthermore, the seat ring is easy to assemble.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing an embodiment of the present invention;
The figure is an enlarged sectional view of the main part of the seat ring of the present invention, Figures 3 to 4 are sectional views of the main part showing other embodiments, and Figures 5 to 7 are partial sectional views showing the conventional example. be. 1... Valve body, 2... Valve body, 3... Valve shaft, 4...
... Seat ring, 7... Fluororesin annular body, 7a
... U-shaped recess, 8 ... elastic ring, 9 ... rigid ring.

Claims (1)

[Scope of utility model registration request] An eccentric butterfly-shaped valve body in which a rotatable valve body is provided within an annular valve body, and a seat ring is provided in a recess on one side of the valve body via a retaining ring so as to be in pressure contact with the outer peripheral surface of the valve body. In the valve, the seat ring includes a thin fluororesin annular body whose outer diameter is smaller than the inner diameter of the recess of the valve body and a U-shaped cross section, and a thin annular body made of fluororesin that is sequentially inserted into the U-shaped recess of the thin fluororesin annular body. The projections or recesses formed on both sides of the thin-walled fluororesin annular body near the outer periphery are connected to the recesses or projections formed in the recess of the valve body and the retainer ring, which are comprised of an fitted elastic ring and a rigid ring. An eccentric butterfly valve characterized by being engaged.