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Qublock globe valves are used for applications requiring zero emission and tight shutoff with a metal seat under high pressure and temperature as well as other exotic services. The QG series is especially designed for slurries or fluids containing solids. This design has several strengths, including flexibility of design and application of various hard facing.
|Rating||Class 150# to 2500# , JIS 10K to 63K|
|Size||1/4” to 24”|
|Leakage Rate||Class VI, API598|
|Type||Bolted Bonnet, Pressure Bonnet, Solid Disc, Free Disc, Back Seat|
|Design Code||API609, ASMEÄB16.5, ASME B 16.10, ASME B16.34, ISO5752, MSS-SP68|
Metal friction occurs owing to vertical movement of steam; this phenomenon causes galling. To prevent galling, the QG series can provide aluminum bronze yoke busing and nitride as options.
The special stem sealing was designed to meet the latest ISO 15848 fugitive emission standard. This packing is made of expanding graphite, which has various advantages such as heat resistance, chemical resistance, less stress relaxation, and low creep. Owing to the special structure, the required tightening pressure is approximately half of that required in the conventional version. In addition, durability is improved, as compared to that of conventional packing. Thus, this packing provides stabilized seal performance for a valve over the long-term under frequent function and severe service conditions.
Qublock is managed according to the international NACE regulations MR0175 and MR0103, which are provided upon request. NACE specification MR-0175/0103 is available for use in applications where the presence of wet H2S generates the risk of stress corrosion cracking. According to processed data, a proper NACE application is also recommended by Qublock engineers.
Valves with a heating/cooling jacket, full jacket, and semi-jacket are available. The Qublock jacket design is provided on the valve body and gland packing position to prevent the fluid status from changing. Jacket design involves fluid fixation.
The QG series is normally used for critical service. Therefore, a heavy duty type handwheel should be selected as a standard.