DD363Y Butt-Weld Top-Entry Cryogenic Butterfly Valve (Online Repairable) Overview

The DD363Y butt-weld top-entry ultra-low temperature butterfly valve is a specialized valve designed for -196°C grade ultra-low temperature media such as liquefied natural gas (LNG), liquid oxygen, liquid nitrogen, liquid helium, and liquid ethylene. It features butt-weld ends that are permanently connected to the pipeline, eliminating the risk of flange leakage. Its top-entry design allows for online maintenance by removing the bonnet and extracting internal core components such as the stem, disc, and seat from the top without cutting the valve out of the pipeline. The valve utilizes a triple-offset metal hard seal structure, with the disc sealing surface overlaid with hard alloy, ensuring tight shut-off and a long service life. This valve is widely used in critical systems requiring high reliability and convenient online maintenance, such as LNG terminals, air separation units, and cryogenic liquefaction plants.

DD363Y Butt-Weld Top-Entry Cryogenic Butterfly Valve (Online Repairable) Product Image

DD363Y Butt-Weld Top-Entry Cryogenic Butterfly Valve (Online Repairable) Features

1.  Butt-Weld Connection for Permanent Seal: The butt-weld ends are welded directly to the pipeline, forming an integral connection. This completely eliminates potential leak points associated with flanged connections, meeting the absolute sealing requirements of ultra-low temperature service.

2.  Top-Entry Design for Online Maintenance: The unique top-entry structure allows for online inspection, cleaning, or repair. Internal trim components (stem, disc, seat) can be removed from the top without cutting the pipeline or removing the valve body from the line, significantly reducing maintenance downtime and costs.

3.  Cryogenic Treatment and Low-Temperature Materials: All critical components are made from LCB or LF2 low-temperature alloy steel, or forged F304/F316L stainless steel. Parts rated for ≤ -101°C undergo cryogenic treatment to ensure low-temperature toughness and dimensional stability at -196°C.

4.  Triple-Offset Hard Metal Seal: Utilizes a triple-offset sealing design for friction-free opening and closing. The sealing surfaces are overlaid with hard alloy, providing resistance to low temperatures, erosion, and wear, achieving bidirectional zero-leakage performance.

5.  Extended Bonnet for Anti-Freeze Protection: Features an extended bonnet designed according to the temperature rating, positioning the packing away from the low-temperature zone. This prevents packing freeze-up and stem seizure, ensuring flexible and reliable operation under cryogenic conditions.