| Metallic wrapping pad B
The metal spirally-wound gasket adopts high-quality SUS304 or SUS316 ("V" or "W"shape) metal strips, other alloy materials and some flexible materials like graphite, asbestos, PTE and non-asbestos, which are overlapped and wound spirally with each other. The metal strips are fixed on the initial and terminal ends by means of spot welding. The metal spirally-wound gasket has the best resilien ce among the semi-metal hermetic gaskets. Its structural density can be made subject to different locking forces. Also the internal and external steel rings can be used to control its maximum compaction. It's not demanding for the surface precision of the flange sealing surface contacting the spirally-wound gasket. It's especially applicable for such occasions as uneven load, slack joint, periodical changes of temperature and pressure, impact or vibration. It's an ideal static seal element for flange connection in valves, pumps, heat exchangers, towers, manholes,handholes and so on.
Application scope of spirally-wound gasket：
Sealing of flange connection in pipelines, valves, pressure containers, condensers, heat exchangers, towers, manholes, handholes and so on in such industries as petroleum, chemical engineering, metallurgy, electricity, shipping and machinery.
Type of metallic wrapping pad：
| Type |
Section shape |
Code name |
Thickness(mm) |
| Basic wrapping pad |
 |
A |
3.2 |
4.5 |
| Wrapping pad with inner ring |
 |
B |
|
4.5 |
| Wrapping pad with outer ring |
 |
C |
|
4.5 |
| Wrapping pad with inner and outer rings |
 |
D |
|
4.5 | |
Structural material of metallic wrapping pad：
| Filling |
Temperature(℃) |
Max operating pressure(kg/cm2) |
| Asbestos wrapping |
-200~550 |
250 |
| Graphite wrapping |
-150~450 |
100 |
| Teflon wrapping |
240~260 |
100 |
The following table lists metallic materials for inner ring and wrapping:
| Product name |
AISI |
Hardness(HB/HV) |
Temperature(°C) |
| 304 Stainless steel |
304 |
130~180 |
-250~+550 |
| 316 Stainless steel |
316 |
130~180 |
-100~+550 |
| 316L Stainless steel |
316L |
130~190 |
-100~+550 | Outer ring is often made from carbon steel subject to anti-corrosive treatment.
Flange type and form of wrapping pad:
| Flange type |
Spiral wound gasket form |
| Flat face flange(F.F) |
Wrapping pad with outer ring only |
| Wrapping pad with inner and outer rings |
| Raised face flange(R.F) |
Wrapping pad with outer ring only |
| Wrapping pad with inner and outer rings |
| Male and female flange(M & F) |
Basic wrapping pad |
| Wrapping pad with inner ring only |
| Tongue and groove flange(T & F) |
Basic wrapping pad |
| Wrapping pad with inner ring only |
| Flat and groove flange(F & G) |
Basic wrapping pad |
| Wrapping pad with inner ring only |
Wrapping pad thickness tolerance:
| Item |
Thickness(mm) |
Tolerances(mm) |
| Gasket thickness |
4.5, 3.2 |
+0.2
-0.1 |
| Ring thickness |
3.0 |
±0.24 |
Key technical parameter of metallic wrapping pad:
| Wrapping pad coefficient |
m=2.5-4 |
| Wrapping pad service pressure |
≤25MPa |
| Wrapping pad service temperature |
-196℃-700℃(Oxidizing medium no higher than 600℃) |
| Wrapping pad minimum pretension specific pressure |
y=68MPa |
The following table refers to tolerances for the diameter of wrapping pad (namely the nominal pipe diameters for the use of flange):
| |
DIM(mm) |
ANSI B16.5
BS1560(mm)
Mss sp-44 |
API605 |
Tolerances |
Inner ring diameter
Pad inner diameter |
<=600 |
＜=24" |
＞＝26" and ＜=34" |
±0.5 |
| ＞600 and ＜=800 |
＞24" and ＜=34 |
＞＝36" and ＜=60" |
±0.9 |
| ＞800 and ＜=1600 |
＞34" and ＜=60" |
|
±1.3 |
＞1600
|
＞60" |
|
±1.6 |
| Pad outer diameter |
＜=600 |
＜=24" |
＜=24"
|
±0.9 |
| ＞600 and ＜=160000 |
＞24" and ＜=60" |
|
±1.8 |
| 1600 |
＞60"
|
|
±2.2 |
| Outer ring diameter |
|
|
＞1/2" and ＜=60" |
±0.9 |
| ＜=600 |
＜=24" |
|
0-1.0 |
| ＞600 and ＜=1000 |
＞24" and ＜=34" |
|
0-1.8 |
| ＞1000 and ＜=1600 |
＞34" and ＜=60" |
|
0-2.2 | | Note: We also tailor products based on JIS, JPI or customer requirement
Ordering information: The following parameters should be specified during ordering for metallic wrapping pad
Example:
1. Type of metallic wrapping pad: A B C D
2. Flange standard: ASME B16.20
3. Pipe through diameter, pressure rating: 2"150Lbs
4. Material: inner ring SS316; metallic wrapping belt SS316; packing belt: graphite; outer ring; carbon steel
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Metal Gaskets
