Metallic Serrated and Flat Gaskets

These gaskets are manufactured from cold rolled metal plate, and include flat gaskets made of metallic sheet which is processed into a specifield dimension and shape, and serrated gaskets with concetric grooves to improve sealing property.

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VALQUA No.
6540HP
Product name
Serrated metal gasket with VALQUAFOIL sheet bonded to seal surfaces for a substitution of joint sheet.

Features1
This is a 6540H-Series for piping with dimensions optimally set as an alternate for a compressed non-asbestos fiber sheet.
Features2
Component metallic materials : SUS304、SUS316L

Applicable fluids
Water, Sea water, Hot water, Steam,Crude oil, Alcohol, Animal & vegetable oil, Heat transfer oilGeneral solvent, Weak acid, Weak alkali,Air, Nitrogen gas, Inert gas,Exhaust gas,Inflammable gas,Poisonous,Extremely low temperature liquids,etc.
Inappropriate fluid
Oxidizing acids such as hot, concentrated sulfuric acid and concentrated nitric acid
Dimensions
JIS 10K Max. 600A, JPI class 150, 300 Max. 24B
Type
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Remarks
用途
This gasket is used for hot and high-pressure vapor and process fluid tower, heat exchanger, autoclave, valve bonnet, etc and applicable to raised face flange, grooved flange and male-female flange.

■ Available ranges

Temperature(℃) Pressure(MPa)
-240〜400 14.0

■ FAQ

Q. What kind of product is 6540HP?

A. Just as in 6540H, the basic structure of 6540HP consists of flexible graphite pasted on a serrated gasket surface, but the dimensions of HP are set for standardized flange and it can be used with the same tightening force as a conventional compressed non-asbestos fiber sheet.

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.

■ VALQUA HAND BOOK TECHNICAL DATA

■ VALQUA HAND BOOK DIMENSIONAL DATA


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