Spiral Wound Gaskets use Non-Asbestos inorganic paper, VALQUAFOIL™ (expanded graphite) and VALFLON™ (PTFE) tape as filler materials, and exhibit good elasticity by means of a V-shaped hoop.

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Product name
BLACKTIGHT (with inner ring)

Version of Spiral wound gasket using VALQUAFOIL tape applied as filler material with inner ring
A gasket with an inner ring is used for a male-female flange. The inner ring not only reinforces the gasket but also decreases the clearance between the pipe's inner diameter and the gasket, as well as preventing accumulation of fluids and errosion of corner areas. Please use a product with an inner ring if the pressure rating of the flange is Class 900 (JIS 63K) or greater, or if the nominal diameter of the flange is 650A (26B) or greater.
Excellent airtightness greatly improves sealing performance against gas in general and vacuum.
Excellent response to heat and pressure cycles reduces the frequency of retightening.
They also have excellent radiation resistance (products complying nuclear power specifications are available).

Applicable fluids
Water, Sea water, Hot water, Steam,Crude oil, Alcohol, Animal & vegetable oil, Heat transfer oil,General solvent, Weak acid, Weak alkali,Strong oxidizing acid, strong alkali,Air, Nitrogen gas, Inert gas,Exhaust gas,Inflammable gas,Poisonous,Extremely low temperature liquids,
Inappropriate fluid
In particular best suited as gaskets for use handling high temperature & high pressure steam (except HTS), as well as very low temperature fluids such as LNG, liquid nitrogen and liquid hydrogen.

■ Dimensions

Standard Flange

For JIS pipe flanges=10K、16K、20K、30K、40K、63K For JPI and ANSI pipe flanges=Classes 150, 300, 400, 600, 900, 1500, 2500 Gaskets complying with other standards such as ASME and MSS are also available. ▼ For non-st

Non-Standard Flange

Gasket thickness(mm) Manufacturing ranges
3.2(T) 10〜1500
4.5(V) 10〜3000
6.4(W) 300〜3400

Products with a gasket thickness of 6.4 mm can be fabricated with the outer diameter of the outer ring of up to 3,500.

The sign "( )" shows thickness classifications.

Round type gaskets are available.

■ Design data

Basic design With outer ring With inner ring With inner/outer ring
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Filler material: VALQUAFOIL tape

■ Available ranges

Temperature(℃) Pressure(MPa)
-270〜450 30.0

1. Temperature and pressure show individual service limits.
2. The above temperature ranges vary depending on the material used for the hoops and the inner & outer rings.

■ Design criteria

Gasket factor”m” Minimum design
seating stress"y"
tightening stress
tightening stress
3.0 68.9 30.0 50.0

The recommended tightening stress are the pressures required under normal conditions, and correspond to the projected area of the gasket, where fluid pressure is not taken into consideration.

Separate consultation is required, where flange deformation is anticipated for large diameter gaskets.

■ The fluid-wise available ranges

The fluid-wise available ranges

■ Upon placing order


Q. Please introduce the spiral wound gasket that can be used for aluminum flange

A. We recommend the usage of a spiral wound gasket that uses an aluminum hoop for soft flanges like aluminum and copper alloy flange. However, the thickness must be 4.5t.

Q. Please tell me about spiral wound gaskets that are used in extremely low temperature

A. The bolt material that is used in extremely low temperature is usually stainless, so it will have a weaker tightening force than the bolts like SNB7 that are often used in spiral wound gaskets. We therefore recommend 6596V when the tightening force is insufficient. It is also possible to use 6596V if sufficient tightening force can be added.

Q. Is it possible to manufacture the spiral wound gasket in sizes other than the standard size?

A. Yes, it is possible for both the gasket main unit and inner & outer rings as long as you specify the size. However, please contact us because there is a range in which manufacturing is possible such as for the width.

Q. Please tell me about the difference in the gasket dimensions between flanges of the JPI and ASME/ANSI standards.

A. JPI basically quotes from ASME/ANSI, so there are cases in which the dimensions differ slightly due to rounding error during the millimeter conversion of the original number. We understand that, in actual use, the function of the gasket is fulfilled to an equivalent degree by both dimensions.

Q. I want to control the width of the opening in the flange such as with a sheet gasket. How should I do this?

A. Control with width of the opening in the flange is prone to cause a margin of error and an accurate tightening stress cannot be obtained. It is effective for uneven tightening, so please use it in conjunction with control of tightening torque.

Q. Why does leakage occur during stop or re-operation even though there are no problems during plant operation?

A. Expansion and contraction of the flange, bolt, pipe and the like will occur due to temperature changes. As a result, a tendency of reduced tightening force in the gasket main unit is often observed when the temperature decreases (including low temperature at the time of initial re-operation), and leakage occurs due to relaxation. We therefore generally recommend a retightening of the gasket before re-operation after the first heat addition.

Q. Is retightening effective when leakage occurs?

A. Yes, it is effective. We ask that retightening during leakage be performed after relieving internal pressure. However, there are also points to keep in mind for each product, such as the possibility of damage as a result of temperature-induced hardening in the case of a compressed non-asbestos fiber sheet.

Q. I am not sure which gasket to select, so could you select it for me?

A. If you contact us together with your operating conditions, we will recommend an appropriate product based on our technician's selection.