Bray Series 35F Large Double Flanged Butterfly Valve, NPS 32-60

Bray Series 35F large double flanged butterfly valve, NPS 32 to 60

The Bray Series 35F is a resilient seated, double flanged butterfly valve for very large diameters, NPS 32 to 60 (DN 800 to DN 1500), designed for high chloride service. It is the version of the large Series 35/36 family that Bray developed for seawater, flue gas desulphurisation (FGD) and mining duties, where standard cast iron or stainless discs do not last. Disc materials include duplex stainless steel, super austenitic stainless steel and Hastelloy, and the body is offered in cast iron, ductile iron or Hastelloy. Seven Star LLC supplies Bray valves in Oman and the GCC as an independent supplier in Muscat.

Series 35F technical specifications

Why a chloride-resistant disc matters on Series 35F

Seawater, brine and many FGD scrubber slurries contain chlorides that attack the standard materials of butterfly valve discs, causing pitting and crevice corrosion that starts at the disc edge, which is the sealing surface. By offering duplex stainless steel, super austenitic stainless steel and Hastelloy discs, the 35F gives the owner a choice according to chloride level, temperature and oxygen content. The disc edge and hub are spherically machined and hand polished according to the recommended specification, which gives low torque and a sealing surface that stays smooth after years of cycling.

A material selection should therefore be made together with the water analysis. A cooling water intake with sea water at ambient temperature may be well served by duplex stainless, while a hot, acidified scrubber slurry may call for Hastelloy. This is why the body and disc materials are on the ordering form and not just defaults.

Seat, stem and body design of the 35F

The seat is a tongue-and-groove design with a primary hub seal and a molded flange O-ring suited to weld-neck and slip-on flanges, so no flange gaskets are needed. The seat completely encapsulates the body, isolating the body from the line medium, which protects the cast iron or ductile iron from corrosion. Bonded EPDM suits water and seawater, and bonded Buna-N suits oils and hydrocarbons within the temperature limits.

The stem is one piece, with an internal connection to the disc so that there are no disc screws or pins exposed in the flow path as leak paths. Upper and lower bronze stem bearings absorb actuator side thrust and reduce friction torque, and the stem packing is externally adjustable without removing the actuator. A stem retention system prevents blowout if the stem were to fail.

Dimensions and weights of the large Series 35F valves

The weights and dimensions sheet gives dimensions for each size in inches and millimetres, and these valves are heavy. The weight of a 32 in. (800 mm) valve is 441 kg, a 48 in. (1200 mm) valve is 1,306 kg and a 60 in. (1500 mm) valve is 2,572 kg, before the actuator. Lifting plans, pipe supports and a crane are normal parts of any installation project, and the actuator adapter code and top plate details are given in the attached sheet.

Where Series 35F fits among Bray butterfly valves

Bray’s resilient seated butterfly valve families cover small to very large diameters. Series 30/31 and 20/21 cover common wafer and lug sizes, Series 32/33 covers NPS 22 to 36, and Series 35/36 covers NPS 22 to 120 with full flanged bodies. The 35F is the chloride-resistant version for NPS 32 to 60 and sits alongside other family variants such as the 36H and 31H. If the line is steam or hot oil, a double offset valve such as McCannalok is a better choice than a resilient seat limited to 250°F.

Selection and ordering checklist for 35F

• Size and flange drilling: ASME B16.1 Class 125, B16.5 Class 150, B16.47 or EN 1092 PN10/PN16.
• Pressure including surge: 75 psi bidirectional or 30 psi dead-end.
• Water or slurry analysis: chloride level, pH, temperature and solids, to choose body, disc and seat.
• Actuator: manual gear, pneumatic or electric, with torque and operating time.
• Certification such as NSF 61 for potable water, SIL or ATEX when required.

Installation and maintenance of large 35F valves

Lift only by the body lifting points and keep the disc slightly open during storage. Install between flanges with the disc partly open, centre the valve, and tighten the bolts in a star pattern following the bolting guide. Because the seat serves as the flange seal, do not add gaskets and do not over-torque flange bolts. After the first few cycles, check the stem packing and the actuator mounting bolts. In service, inspect the seat and the disc edge at shutdowns; chloride attack shows as pitting on the disc edge first. A spare seat kit, stem packing and actuator adapter stocked for critical lines reduces downtime.

Series 35F applications in Oman and the GCC

Seawater intake and outfall lines, desalination plant feed and brine, power station condenser cooling water and FGD absorber lines use large diameter valves with chloride resistant materials. In the Gulf, seawater is warm and high in salinity, which makes the corrosion allowance and material selection of the disc critical. Large diameter isolation valves should also be considered together with water hammer and surge behaviour so that closing time is chosen sensibly.

Information to send with a 35F RFQ

• Size, flange standard, quantity and installation orientation.
• Medium, chloride level, temperature, pressure and surge.
• Body, disc and seat material preference.
• Actuator data and any certificates required.

Documents and quotation

The Bray Series 35F weights and dimensions sheet is attached on this page with size, flange and actuator adapter data.

Send the line data and water analysis and Seven Star LLC will confirm the Series 35F configuration and quote supply to Oman and the GCC.