Lens ring

Metal lens gasket

High pressure pipe connection, the widely used lens gasket sealing structure.Lens gasket seal face were spherical, contact with the pipeline cone sealing faces, the initial state for a loop.Under the pre-tightening force, lens pad in contact produce plastic deformation, the loop into a ring, good sealing performance.Due to the contact surface is made up of spherical and cant naturally formed, in a gasket is easy.Lens gasket seal belongs to forced sealing, sealing surface for spherical surface and conical surface contact, easy appear indentation, poor interchangeability of parts.In addition, the gasket manufacturing cost is higher, processing also more difficult.

Metal lens gasket performance characteristics:

1, high temperature resistant, resistant to high pressure, suitable for high pressure flange;
2, reliable sealing persistent;
3, to adapt to the working conditions of pressure and temperature fluctuations;

Metal lens gasket application scope: general machinery industry in our country the current Angle type high pressure valve end flange, USES the lens gasket seal, apply to the nominal pressure of 16.0 ~ 32.0 Mpa.Nominal diameter is 3 ~ 200 mm;Use temperature was minus 30 ~ 200 ℃, often used for sealing of high-pressure hydrogen acid medium.

Metal ring gasket first comes from the United States, in the 1920 s, the first to use in boiler, then used for manhole cover, autoclave other Windows sealed, later in the oil production and refining industry particularly valued.With the increase of temperature and pressure of the steam power plant, metal ring gasket have been used more and more widely.

Metal lens gasket main structural forms:

Metal lens gasket material selection:

material	Maximum hardness		mark	℃
material	Brinell HB	Rocknell HB	mark	Min	Max
Soft Iron	90	56	P	-40	540
Low C/S	120	68	S	-60	500
SS410	170	86	S410	-40	850
SS304	160	83	S304	-250	540
SS316	160	83	S316	-200	815
SS347	160	83	S347	-200	870
4-6%Cr,0.5% Mo,	130	72	F5	-40	650
Copper	80	-	C	-100	315
Aluminum	35	-	A	-200	425
Inconel 600	150	78	Y	-100	1095
Inconel 825	150	78	W	-100	1095
Monel 400	150	78	M	-100	760
Titanium	215	77	T	-200	540
Nikel 200	110	58	N	-200	760
Hastelloy B2	230	121	X1	-100	1095
Hastelloy C276	210	110	X2	-100	1095

The size of the metal lens gasket limit deviation:

Name of size	Generation of no.	Limit deviation
Ring pad pitch diameter	P	+ / - 0.18
The width of the ring gasket	A	+ 0.20 - 0
The height of the ring gasket	H	+ 0.20 - 0
Metal lens mat bottom width	C	+ 0.20 - 0
23 ° Angle		Plus or minus 0.15 °
Radius of ring gasket	R	+ / - 0.4
Metal lens mat all 23 ° Angle of the plane, the surface roughness shall be no greater than 0.8 microns

Metal lens gasket main performance parameters:

Coefficient of gasket
m=5.50-6.50

Gasket using pressure ≤32MPa

Gasket using temperature - 196 ℃ to 1000 ℃

Than the minimum preload pressure y=126.6-182.8MPa

Metal lens pad technology standards:

Can provide any size of standard and non-standard, including API 6 a, ASME B16.20, DIN 2693-67, JPI - 7-23-72 - s, DIN - 2696-1999 and other standards.

Domestic relevant standards:

JB/T 2777-1992 | PN16.0 ~ 32.0 MPa without aperture lens gasket
JB/T 2776-2010 | valve parts high-pressure lens pad
JB90-1959 type of flange sealing surface lens with metal gasket

Does the actual application condition is complex, the above parameters are for reference only do not make any guarantee is requested.

Coefficient of gasket	m=5.50-6.50
Gasket using pressure	≤32MPa
Gasket using temperature	- 196 ℃ to 1000 ℃
Than the minimum preload pressure	y=126.6-182.8MPa