ʻO ka pad wahī metala kahi mea sila i hoʻohana pinepine ʻia, i hana ʻia me nā metala like ʻole (e like me ke kila kila, keleawe, alumini) a i ʻole ka ʻōwili pepa alloy. Loaʻa iā ia ka elasticity maikaʻi a me ke kūpaʻa wela kiʻekiʻe, ke kūpaʻa kaomi, ke kūpaʻa corrosion a me nā ʻano ʻē aʻe, no laila he ākea nā noi i ka ʻoihana valve.

Hoʻohana akamai ka papa wili hao i ke kūpaʻa wela, ke kūpaʻa a me ka ikaika o ka metala a me ka palupalu o nā mea ʻaʻole metala, no laila ʻoi aku ka maikaʻi o ka hana sila, a ʻo ka hana o ka papa graphite wili kila kila kila maikaʻi loa. ʻOi aku ka liʻiliʻi o ka lakio precompression ma mua o ka papa wili asbestos, a ʻaʻohe kīnā o ka leakage capillary fiber asbestos. I loko o ka medium aila, hoʻohana ʻia ʻo 0Cr13 no nā ʻāpana metala, ʻoiai ua ʻōlelo ʻia ʻo 1Cr18Ni9Ti no nā media ʻē aʻe.

Hana ʻia ke kila kila me ka wili graphite palupalu i loko o ka ʻano kinoea, me ke kaomi o 14.7MPa, a hiki ke hoʻohana ʻia i loko o ka wai a hiki i 30MPa. Mahana -190 ~ + 600 ℃ (i ka nele o ka oxygen, hiki ke hoʻohana ʻia ke kaomi haʻahaʻa a hiki i 1000 ℃).

He kūpono ka papa wili no nā mea hoʻololi wela, nā mea hana, nā paipu, nā kiwikā, a me nā flanges komo a me nā puka o ka pamu me nā loli nui o ke kaomi a me ka mahana. No nā kaomi waena a kiʻekiʻe paha a me nā mahana ma mua o 300 ° C, pono e noʻonoʻo ʻia ka hoʻohana ʻana i nā apo o loko, waho a i ʻole o loko. Inā hoʻohana ʻia ka flange concave a me ka convex, ʻoi aku ka maikaʻi o ka papa wili me ke apo o loko.

Hiki ke loaʻa kahi hopena sila maikaʻi ma ke kau ʻana i nā papa graphite palupalu ma nā ʻaoʻao ʻelua o ka pad wili graphite palupalu. ʻO ka paila wela ʻōpala o kahi hale hana mea kanu kemika nui kahi lako koʻikoʻi o ka mahana kiʻekiʻe a me ke kaomi kiʻekiʻe. Hoʻohana ʻia ka pad wili graphite palupalu me ke apo waho, ʻaʻole e liki ke piha ka ukana, akā e liki ke hoʻemi ʻia ka ukana. Hoʻohui ʻia kahi papa graphite palupalu 0.5mm ka mānoanoa ma nā ʻaoʻao ʻelua o ka gasket a ʻokiʻoki ʻia i loko o ke ʻano arc. Hana ʻia ka ʻāpana hui me ka hui ʻūhā diagonal, kahi i hoʻohana maikaʻi ʻia.