Ring joint gasket

These gaskets are made of single metal to be used for pipe flanges in the lines handling high temperature & high pressure steam, as well as for ring joint flanges of valve bonnets.

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Product name
Double Cone shaped gasket(Double cone)

Ring Joint Gasket is made of single metal to be used for pipe flanges in the lines handling high temperature & high pressure steam, as well as for ring joint flanges of valve bonnets.
It can reduce the strength of bolts and flanges compared to simple compressed metallic gasket.
No. 550-ZW is self-seal type gasket with a double corn cross section. When of soft iron, often used with aluminum board or expanded graphite tape (VF-70). Precision surface finishing is not needed so that there is no damage to the sealing surface.

Applicable fluids
Water, Sea water, Hot water, Steam,Crude oil, Alcohol, Animal & vegetable oil, Heat transfer oilGeneral solvent, Weak acid, Weak alkali,Strong oxidizing acid, strong alkali,Air, Nitrogen gas, Inert gas,Exhaust gas,Inflammable gas,Poisonous,Oxygen,Extremely low temperature liquids,
Inappropriate fluid
Used for vessel or cover of heat exchanger at high temperature and high-pressure.

■ Manufacturing ranges

Please feel free to contact us.

■ Max. hardness by material

Name Max. hardness(HB)
Low carbon steel 120
Pure iron 90
Copper 60
SUS304 160
SUS304L 150
SUS310S 160
SUS316 160
SUS316L 150
SUS321 160
SUS347 160
SUS430 170
5Cr-0.5Mo steel 130
Monel metal 140
Titanium 140
Aluminum 40
Nickel 120

■ Upon placing order


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. 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. 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.