JPH0642677A - Bellows seal valve - Google Patents

Abstract

PURPOSE:To provide a bellows seal valve incorporating bellows excellent in strength and corrosion resistance. CONSTITUTION:A bellows seal valve comprises a valve body 1 having a valve seat 3, a valve rod 3 slidably provided in the valve body 1, a valve element 4 provided to one end part of the valve rod 2 and adapted to abut against the valve seat 3, seal bellows 5 in two layers attached to the outer periphery of the valve rod 2 in the valve body 1. The seal bellows 5 in two layers, are composed of an atmospheric side bellows part 11 made of a material having a high strength, and, a liquid contact side bellows part 12 made of a corrosion resistant material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bell seal valve provided with a double seal bellows.

[0002]

2. Description of the Related Art The flow rate of a high temperature and high pressure internal fluid is adjusted by a bellows-sealing valve. Such a bell seal valve generally has a valve body having a valve seat, a valve rod slidably provided in the valve body, and a valve seat provided at an end of the valve rod to abut against the valve seat. It is provided with a valve body and a two-layer seal bellows mounted around the valve rod in the valve body. In such a bell seal valve, a seal bellows is attached around the valve rod. This seal bellows isolates the internal fluid flowing in the gap between the valve body and the valve seat from the gland portion of the bellow seal valve, and the liquid under high temperature and high pressure conditions is removed from the gland portion. I try not to leak it.

In order to prevent leakage of liquid under high temperature and high pressure conditions, the seal bellows are required to have high strength to withstand high pressure and corrosion resistance to be resistant to liquid corrosion. In order to meet these requirements, the bellows of the bellows-sealing valve are constructed by stacking two bellows.

[0004]

However, the conventional method 2
For example, Inconel 718 is used as a bevel for a stack of sheets.
Since they were composed of the same material such as, the strength resistance and the corrosion resistance were not always sufficiently satisfied at the same time. The material of Inconel 718 is sufficiently strong, but its corrosion resistance is limited. For this reason, there has been a problem that damage due to stress corrosion cracking is likely to occur in the liquid-contact side veloc part on the side in contact with the liquid depending on the condition of the internal fluid. This also poses a problem that it is necessary to replace the bellows frequently.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems of the prior art and to provide a bell seal valve having a bellows excellent in strength resistance and corrosion resistance.

[0006]

In order to achieve the above object, the present invention provides a valve body having a valve seat, a valve rod slidably provided in the valve body, and an end of the valve rod. A valve body provided on the valve seat and abutting on the valve seat; and a stack of two bellows for seals mounted around the valve rod in the valve body.
The sheet-sealed bellows is characterized in that it is composed of an atmosphere side bellows portion made of a strong member and a liquid contact side bellows portion made of a corrosion resistant member.

[0007]

When the internal fluid is at high temperature and high pressure, since the atmosphere side veloc part of the two-sealed velor for sealing is made of a strong member, the inner side of the velor at atmospheric pressure and the high temperature are high. A pressure differential can be maintained between the outside of the bellows which is in contact with the high pressure internal fluid. Further, since the liquid contact side bellows portion is made of a corrosion resistant member, it is not corroded even if it comes into contact with a corrosive internal fluid.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a bell seal valve according to the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 indicates a valve body, and a valve rod 2 is slidably provided in the valve body 1. The valve body 1 is formed with flow passages 1a and 1b through which an internal fluid, which is a flow rate control target of the bellows-sealing valve, passes. The valve body 1 has a valve seat 3 at the ends of the flow passages 1a and 1b, and a valve body 4 that abuts the valve seat 3 is provided at the tip of the valve rod 2. Also, inside the valve body 1, there are 2
A plurality of seal bellows 5 are attached. Furthermore, a valve lid 6 is provided on the valve body 1 to seal the valve body 1 with an internal fluid. A gland portion 7 that seals the valve rod 2 is provided around the valve rod 2 above the valve lid 6.

FIG. 3 shows the appearance of the bellows 5. In FIG. 3, A shows the inside of the bellows 5, and B shows the gap between the bellows 5 and the valve body 1.

FIG. 2 shows a part of the side cross section of the bellows 5. The bellows 5 is constructed by stacking two sheets, the inside A side portion of the bellows 5 is an atmosphere side bellows portion 11 that receives atmospheric pressure, and the outside B side portion of the bellows 5 is an internal fluid. It is the liquid contact side bevel portion 12 that comes into contact with. Atmosphere side
The groove 11 is made of Inconel 71, which is a material with excellent strength resistance.
The wetted side bellows portion 12 is made of Inconel 625, which is a material having excellent corrosion resistance.

Since both Inconel 718 and Inconel 625 are made of Inconel material, there is no inconvenient problem both in forming in the bent portion and in welding.

Inconel 625 is replaced with Inconel 71
When combined with No. 8, it has a strength that is sufficiently satisfactory for practical use.

Next, the operation of this embodiment having such a configuration will be described.

First, the general operation of the bellows-sealing valve will be described. When the valve rod 2 is moved upward, the valve seat 3 and the valve body 4
, And the internal fluid flows from the channel 1a to the channel 1b.
In this case, the bellows 5 is compressed in the longitudinal direction and the diameter thereof is increased in the lateral direction, so that the bellows 5 comes into contact with the inner wall surface of the valve body 1. In this way, even if the flow rate of the internal fluid flowing from the flow channel 1a to the flow channel 1b increases, the amount of the internal fluid leaking to the gland portion 7 is suppressed. Further, when the valve rod 2 is moved downward and the valve body 4 is brought into contact with the valve seat 3, the flow rate from the flow passage 1a to the flow passage 1b decreases.

In such a bell-seale valve, when the internal fluid is at high temperature and high pressure, the liquid contact side beloose portion 12 contacts the high temperature and high pressure liquid. Further, the inside of the atmosphere side bellows portion 11 receives the atmospheric pressure, whereas the liquid contact side bellows portion 12 receives the high pressure of the internal fluid side. As a result, the sealing bellows 5 receives a large pressure difference as a whole, but the bellows 5 on the atmosphere side
The gap portion 11 is an Inconel material 7 which is a member having excellent strength resistance.
Since it is composed of 18, it can sufficiently withstand this large pressure.

Further, since the liquid contact side bellows portion 12 is made of Inconel 625 which is excellent in corrosion resistance, it is not corroded even if it comes into direct contact with the internal fluid of high temperature and high pressure.

As described above, according to the structure of the present embodiment, two sheets of the atmosphere-side bevel portion 11 made of a strong member and the liquid-contact side bevel portion 12 made of a corrosion-resistant member are stacked. Since the seal bellows 5 is provided, damage due to stress corrosion cracking is less likely to occur at the wetted side bellows portion even if the internal fluid is at high temperature and high pressure.

Further, since the material of each member of the atmosphere-side bevel portion 11 and the liquid-contact side bevel portion 12 can be selected separately, the strength resistance required for the bezel for sealing. It is possible to easily satisfy practical use and corrosion resistance.

Further, it is not necessary to replace the bellows 5 frequently. Moreover, the safety of the bellows-sealing valve is ensured, and the reliability of the equipment using the bellows-sealing valve can be improved.

[0021]

As is apparent from the above description, according to the present invention, a double-layered sealing bellows is composed of an atmosphere side bellows portion made of a strong member and a corrosion resistant member. Since the structure is composed of the liquid contact side veloc part, it is possible to prevent the stress corrosion cracking of the veloc from occurring easily.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a bellows-sealing valve according to the present invention.

FIG. 2 is a partial side view of the bellows of an embodiment of the bellows-sealing valve according to the present invention.

FIG. 3 is a plan view of the bellows in the embodiment of the bellows-sealing valve according to the present invention.

[Explanation of symbols]

 1 Valve body 2 Valve rod 3 Valve seat 4 Valve body 5 Bellows 6 Valve lid 7 Ground part 11 Atmosphere side veloc part 12 Wetted side veloc part A Inside of velour B Bellows and valve body Gap between

Front Page Continuation (72) Inventor Masato Kudo 66-2 Horikawa-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Engineering Co., Ltd. (72) Masao Yamadera 1 Shin-Nakahara-cho, Isogo-ku, Yokohama, Kanagawa Address Ishi Kawashima Harima Heavy Industries Co., Ltd. (72) Inventor Yasuhiro Yamashita 1-14 Nakamachi, Moji-ku, Kitakyushu, Fukuoka Prefecture Okano Valve Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A valve body having a valve seat, a valve rod slidably provided in the valve body, a valve body provided at an end of the valve rod and abutting against the valve seat, and a valve body Of the seal bellows attached to the periphery of the valve rod of the above, and the above-mentioned two-lap seal bellows are an atmosphere side bellows portion formed of a strong member and a corrosion resistant material. A bell seal valve comprising a liquid contact side bellows portion made of a flexible member.