Bray Series 32/33 Large Wafer Butterfly Valve, NPS 22-36

Large wafer butterfly valve for water mains and cooling circuits

The Bray Series 32/33 is a one-piece wafer butterfly valve for the 22 to 36 inch (550 to 900 mm) range, carrying the design features of Bray’s smaller resilient seated valves up to large pipe sizes. Series 32 is rated 75 psi (5.2 bar) and Series 33 is rated 150 psi (10.3 bar), both for bidirectional bubble-tight shutoff with downstream flanges in place. High Cv ratings, few parts exposed to the line medium and a symmetrical disc profile that reduces turbulence and increases pressure recovery are the main selling points Bray prints.

Typical uses for valves of this size are cooling-water circuits, raw and treated water transmission, desalination and power-plant intake lines, where wafer construction saves weight and installation length compared with double flanged valves. A thrust bearing keeps actuator torque from loading the stem sideways, which matters at these sizes because large gearboxes or actuators carry substantial weight.

Technical specifications

Source: Bray brochure B-1050, recommended specification sheet and the Series 32/33 dimension sheet (SR drawing 32/33-22/36-in, 2024).

Seat, packing and mounting details

The seat is replaceable and held by a tongue-and-groove method that Bray calls the most advanced in the industry; a molded O-ring removes the need for flange gaskets and the seat isolates the body and stem from the line medium. The primary seal is an interference fit of the molded seat flat with the disc hub, and the secondary seal arises because the stem diameter is larger than the seat stem hole. The stem is blowout-proof, with a steel stem retainer locking the stem assembly.

Large valves are always supplied with an actuator or gear operator and the top flange follows ISO 5211. The dimension sheet lists, for each size, mounting flange hole pattern and stem key sizes for both Series 32 and 33, and a weight from about 181 kg at DN 550 to about 465 kg at DN 900 for the valve alone, so lifting equipment and pipe support need planning.

Where the 32/33 stops and the 35/36 starts

Wafer construction suits sizes to 36 inch. For larger diameters up to 120 inch, or when a full flanged body and externally adjustable packing are needed, use the Series 35/36. For sizes to 20 inch with lug or double flanged bodies, see the 30/31 and 3A/3AH. Please confirm medium, temperature, flange standard, actuator type and torque, and whether NSF/ANSI 61 or marine approvals are needed.

How the Bray Series 32/33 works

The valve is a one-piece wafer body with a disc on a stem. A quarter turn of the stem moves the disc from open to closed. The disc presses into a replaceable seat to give bidirectional shutoff. A thrust bearing keeps actuator torque from loading the stem sideways.

Where the Series 32/33 is used

• Cooling-water circuits
• Raw water transmission
• Treated water transmission
• Desalination lines
• Power-plant intake lines

Selection checklist for the Series 32/33

• Pipe size
• Series 32 or Series 33 rating
• Flange standard
• Body material
• Disc material
• Seat material
• Stem material
• Actuator or gearbox type

Installation, commissioning and maintenance notes for the Series 32/33

Centre the valve between the pipe flanges and tighten the bolts evenly. Keep the disc slightly open while the flange bolts are tightened. Support the weight of the valve and its gearbox. Cycle the valve once before the line is put into service.

Requesting a quotation for the Bray Series 32/33

Please send the size, the pressure rating and the materials you need. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

Series 32/33 valve type

It is a one-piece wafer butterfly valve.

Series 32/33 size range

The range is NPS 22 to 36 (DN 550 to 900).

Series 32/33 pressure rating

Series 32 is rated 75 psi and Series 33 is rated 150 psi.

Series 32/33 shutoff

The shutoff is bidirectional.

Series 32/33 flange compatibility

It fits ASME 125/150 and PN 10 flanges.

Series 32/33 body material

The standard body is cast iron or ductile iron.

Series 32/33 disc

The standard disc is nylon 11 coated ductile iron.

Series 32/33 disc finish

The disc is spherically machined and hand polished.

Series 32/33 stem

The standard stem is 416 stainless steel.

Series 32/33 seat

The seat is replaceable, with EPDM as the standard material.

Series 32/33 seat options

BUNA-N and FKM seats are also offered.

Series 32/33 bearings

Bearings are bronze or PTFE-encapsulated stainless steel.

Series 32/33 thrust bearing

A brass thrust bearing takes the actuator load.

Series 32/33 velocity limit for fluids

The limit for on/off fluid service is 9 m/s.

Series 32/33 velocity limit for gases

The limit for on/off gas service is 54 m/s.

Series 32/33 disc profile

The symmetrical disc reduces turbulence and raises pressure recovery.

Valve records for the Series 32/33

Record the size, the seat material and the actuator fitted.

Choosing the right Series 32/33 rating

Choose the rating from the working pressure of the pipeline.

Documents and quotation

The Bray brochure B-1050 is attached as the datasheet; the Bray page also lists the recommended specification, safety manual, technical manual and the standard valve dimension sheet.

See the wider range of control and isolation valves on our catalogue, or send the model name and order number for a quotation.