JPS6027254Y2 - Multilayer delta gasket - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a gasket for flanges of equipment and piping containing high-pressure fluid.

Conventionally, a ring joint is commonly used as a metal gasket for high pressure.

Depending on the shape, the joint can be oval, offtabonal, or
There are types such as lens type and delta type.

As shown in Figure 1, the delta gasket deforms itself due to the action of internal pressure, and has a self-tensioning effect due to the reaction force of this deformation, which prevents the bolt from elongating due to the action of internal pressure. Since the deformation caused by this self-tightening effect is absorbed, it has the advantage that, unlike other ring joints, a high sealing effect can be obtained with low tightening force.

However, the contact point 2 with the phthalo and the flange 7 is tightened until the stress rises to the plastic region, so that it can be sealed even in the low pressure region where the self-tightening effect does not work.

As the pressure of the internal fluid increases, this tightening force increases and the waist yield area expands.

Generally, a soft material with low hardness is used as a gasket material, and therefore, due to an increase in internal fluid pressure, the entire surface of the gasket yields, causing damage to the gasket and a decrease in restoring force.

In conventional delta gaskets, the entire surface of the gasket yields due to an increase in internal fluid pressure, resulting in damage to the gasket and a decrease in followability due to a decrease in restoring force.

The present invention provides a delta gasket with high rigidity and high conformability without impairing sealing performance.

In the present invention, the delta gasket is divided into a sealing part and a rigid part, each having a two-layer structure of a soft material and a hard material, and both metals are firmly fixed by diffusion bonding.

One embodiment of the present invention will be described with reference to FIG. 2. The delta gasket 3 is comprised of an outer layer 4 that comes into contact with the phthalo and flange 7 and serves as a sealing part, and an inner layer 5 that bears stiffness due to internal pressure.

If ordinary steel materials have sufficient corrosion resistance against internal fluids, a soft material such as 315C is used for the outer layer 4 and a hard material such as 345C is used for the inner layer 5, and the interface is joined by vacuum diffusion welding.

According to the vacuum diffusion welding method, the interface between the two metals can be firmly metallurgically joined, and the amount of deformation caused by joining can be suppressed to a very small amount.

Generally, in the case of a ring joint type metal gasket, since the gasket coefficient is large, the tightening force applied to the gasket is large.

For this reason, the cross-sectional area of the gasket is increased to withstand the tightening force, and the contact area of the sealing part is decreased.
By increasing the contact surface pressure, the breakage resistance and sealing performance of the gasket are ensured, but according to the present invention, by using a soft material for the sealing part, the contact part yields at a low surface pressure. Due to plastic flow, the contact area becomes fully compatible and sealing performance for high-pressure fluids is improved.

In addition, since it has a hard part even with the same cross-sectional area, the resistance to tightening force increases, and since it behaves while remaining elastic, the restoring force increases and the followability is improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional delta gasket during sealing, and FIG. 2 is a sectional view of an embodiment of a multilayer delta gasket according to the present invention. 1.3...Delta gasket, 2...
Contact point, 4... Soft part, 5... Hard part, 6... Lid, 7... Flange.

Claims (1)

[Scope of utility model registration request] Delta gaskets, which have a triangular cross section and are used for flanges of devices that contain high-pressure fluid, have a soft metal material in the outer layer that contacts the flange and seals the fluid, and a soft metal material in the inner layer that receives the entire pressure. A multilayer delta gasket is characterized by having multiple layers of hard metal materials bonded together using diffusion bonding.