The definition of the Spiral Wound Gasket: The Spiral Wound Gasket is made of paper, rubber sheet or copper piece, placed between the two planes to strengthen the sealing material, in order to prevent the leakage of fluid in the static seal between the sealing element.
Metal spiral wound Spiral Wound Gasket is currently widely used as a Spiral Wound Gasket, semi-metallic pad for the best elasticity of the Spiral Wound Gasket, by the V-shaped or W-shaped thin strip with a variety of fillers alternately wound, High temperature, high pressure and adapt to the use of ultra-low temperature or vacuum conditions, by changing the Spiral Wound Gasket material combination, can solve a variety of media on the Spiral Wound Gasket of the chemical corrosion, the structural density can be based on different locking force requirements to produce The main body and the precise positioning, winding Spiral Wound Gasket with metal inner ring and outer positioning ring, the use of internal and external steel ring to control the maximum degree of compression of the contact with the Spiral Wound Gasket flange sealing surface surface accuracy is not high.
1, non-metallic Spiral Wound Gasket: non-texture soft, corrosion-resistant, cheap, but the temperature and pressure resistance is poor. Used for room temperature and medium temperature of the low pressure vessel or pipe flange seal.
Non-metallic Spiral Wound Gaskets include rubber mats, asbestos pads, asbestos rubber mats, flexible graphite mats and polytetrafluoroethylene pads.
2, metal Spiral Wound Gasket: metal Spiral Wound Gasket with steel, aluminum, copper, nickel or Monel alloy and other metal Spiral Wound Gasket.
Metal Spiral Wound Gaskets include: octagonal metal Spiral Wound Gasket, oval metal Spiral Wound Gasket, toothed Spiral Wound Gasket, lock washer
3, semi-metal Spiral Wound Gasket: metal and non-metallic materials made of Spiral Wound Gasket.
Semi-metal Spiral Wound Gasket, including: the basic type spiral wound Spiral Wound Gasket, outer ring winding Spiral Wound Gasket, inner ring wound Spiral Wound Gasket, inner and outer ring winding Spiral Wound Gasket.
Flange Seal Type
Sudden (RF): the surface is a smooth plane, but also the system of dense lines. Sealing surface structure is simple, easy processing, and easy to carry out anti-corrosion lining. However, this contact surface Spiral Wound Gasket contact area is larger, preload when the Spiral Wound Gasket is easy to squeeze on both sides, not easy to compact.
Tongue and groove (TG): sealing surface is composed of tenon and groove, the Spiral Wound Gasket placed in the tank, will not be squeezed. The Spiral Wound Gasket can be narrower, and the force required to tighten the Spiral Wound Gasket is correspondingly small. Even for high pressure, the bolt size is not too large. Therefore, it is more than the above two kinds of sealing surface are easy to get a good sealing effect. The drawback of the sealing surface is that the structure and manufacture are complicated, and it is difficult to replace the Spiral Wound Gasket squeezed in the tank. In addition, the tenon part is easy to damage, in the disassembly or transport process should be noted. The tongue seal is suitable for flammable, explosive, toxic media and high pressure applications. When the pressure is not large, even if the diameter is large, but also a good seal.
(MFM): The sealing surface is composed of a convex surface and a concave surface of the composition, in the concave surface of the Spiral Wound Gasket, to prevent the Spiral Wound Gasket is squeezed out, it can be applied to high pressure occasions.
(PN ≤ 1.6MPa); ring connection surface is mainly used in the neck with the flange flange and the overall flange, the applicable pressure (FF) and the ring connection (RJ): full plane seal suitable for smaller pressure occasions (PN ≤ 1.6MPa) The range is (6.3 MPa ≤ PN ≤ 25.0 MPa).
Other types of sealing surface: For high-pressure containers and high-pressure pipe seal, the sealing surface can be tapered sealing surface or trapezoidal groove sealing surface, respectively, with spherical metal Spiral Wound Gasket (lens Spiral Wound Gasket) and oval or octagonal cross-section metal pad With the film. Sealing surface can be applied to high pressure occasions, but the need for dimensional accuracy and surface finish high, easy to process.
Flange sealing surface and Spiral Wound Gasket with the note
The pattern is the dominant direction of the flange surface roughness, such as: multi-directional, disc-shaped, jagged
The surface finish should be as close as possible to the centerline of the Spiral Wound Gasket, such as circular flanges. The surface lines should be machined as concentric circles or discs, so that lines that pass through the flange surface can be avoided. A straight line through the sealing surface of the grinding line, it will become a direct leak path.
Waveform is the deviation of the whole flatness. Under normal conditions, there is no need to consider the problem of waveform, but there are two cases that need special attention because the excessive degree of waveform is also very difficult to deal with.
The first case is the glass-lined equipment, in which the natural flow of molten glass will form a large degree of wave, and in the higher bolt torque, the glass-lined flange is also easy to deformation. The solution is to use thicker, and highly compressed Spiral Wound Gaskets.
The second case involves warping the flange, if the warping is due to thermal deformation or internal stress caused by the re-processing of the flange on it, if it is due to excessive bolt load or flange thickness is insufficient And the resulting warping, we are generally referred to as "bow deformation", the solution is to redesign the flange with greater stiffness, and sometimes you can add ribs to enhance the structure without replacing the flange, another way is to add more Of the bolts, but also can be less and large bolt program to more and less of the program, thereby increasing the flexibility of the bolt, the connector better combination.
The roughness is calculated from the center of the flange surface to calculate the average of the protrusions and depressions, expressed in ten thousandths of an inch (or meters). For serrated flanged surfaces, typical roughness is 125-500 microinches, and for non-jagged flanged surfaces, the roughness is 125-250 microinches.
Too rough flange, Spiral Wound Gaskets are often not sealed, can only try to use more soft Spiral Wound Gasket, and on the other hand, a high degree of smoothness of the flange, such as polished surface, it is difficult to seal, must To avoid, because the sealing surface requires sufficient "bite marks" to provide sufficient friction to prevent the Spiral Wound Gasket from being blown out or squeezed out, or excessive creep.