• The disc seal ring of the YFL fully metal seated butterfly valve is all metal seal ring not multi-layers seal ring with stainless steel and soft materials like flexible graphite or carbon fiber;
• The YFL metal seal butterfly valve has all metal disc seal ring and metal body seat to realize fully metal seated seal structure to avoid leakage duo to abrasion of graphite or carbon fiber;
• The body seat fixed by two counter rings through bolts can be replaced easily;
• Dynamically balanced sealing system makes the pressure at inlet and outlet side of disc almost balanced so that the butterfly valve will achieve zero leakage bidirectional tight shutoff while the operate torque is reduced effectively to almost 2/3 of normal butterfly valve;
• Triple offset disc structure realizes no friction between disc seal ring and valve body seat when open or close and extends the service life greatly;
• Butt welded connections is usually used between the district heating butterfly valve and the pipeline to avoid leakage from gasket and ensure work safely;
• The lower end cover is welded to the body to prevent leakage and work reliably.

Product range:

• End connection: BW
• Size: 1"～144" (DN25～3600)
• Pressure rating: Class 150～1500 (PN2.5～PN260)
• Operation: Bare stem Lever Gearbox and handwheel Electric Pneumatic
• Body materials: Carbon steel WCB/A105 Low temperature steel LCB/LCC/LC3 High temperature steel WC6/WC9/C5/C12A Austenitic stainless steel CF8/CF8M/CF8C/CF3/CF3M/CG8M Super austenitic stainless steel 254SMO A351 CK-3MCuN Duplex stainless steel UNS S31803/UNS S32205/N08904 Super duplex stainless steel UNS S32750/UNS S32760 Titanium alloy B368 gr.C-2 Hastelloy C276 Monel alloy A494 M-35-1 Aluminum bronze B148 C95800 Inconel 625 Incoloy 825 Alloy 20 CN7M etc.
• Disc seal ring: SS430 F304 F316 etc.
• Body seat materials: SS304 SS316 Stellite etc.
• Stem materials: SS420 17-4PH SS304 SS316 etc.
• Disc materials: WCB CF8 CF8M 904L C95800 etc.

Technical standards:

• Design: ASME B16.34 DIN 3840
• Face to Face: API 609 ASME B16.10 ISO5752
• BW ends: ASME B16.25 ASME B31.8 EN12627
• ISO top flange: ISO5211
• Materials: NACE MR 01-75
• Wall thickness: ASME B16.34
• Test and inspection: API 598
• Fireproof test: API 607 API 6FA
• Pressure and temperature rating: API609 ASME B16.34