Bray Series 740 Bidirectional Knife Gate Valve, NPS 2 to 36

Bidirectional zero-leakage isolation in a single-piece lug body

The Bray Series 740 is a bidirectional knife gate valve built on a one-piece cast stainless steel lug body. Bray designs it for on/off service and isolation of clean, dirty, corrosive or viscous media, and it combines a full-port bore with a mechanically retained, steel-reinforced elastomer seat so that the valve seals tight in both flow directions. The printed size range is NPS 2 to 36 (DN 50 to 900), rated 150 psi (10 bar) up to NPS 24 and 100 psi (7 bar) for NPS 30 to 36.

Bray lists the application areas as pulp and paper (bleach stock, brown stock washers and pump isolation, evaporators and black liquor, paper stock), general industrial service (pneumatic conveyance, raw and treated water, water-conveyed solids), power (fly ash pneumatic conveyance crossover), wastewater (return activated sludge, pump and equipment isolation), chemical process fluids, and ethanol syrup lines. For a water or wastewater plant the practical attraction is a compact lugged valve that can sit at the end of a line and be driven by hand, gear, air or electric power.

Technical specifications

Source: Bray brochure EN_V6000_S740 dated 2026-02-24 and recommended specification sheet EN_RSS_740.

Seat, packing and temperature selection

The seat material sets the temperature window. Bray prints Buna-N at -34 to 194 deg F (-36 to 90 deg C), EPDM at -65 to 248 deg F (-54 to 120 deg C) and Viton at -15 to 392 deg F (-26 to 200 deg C). Packing has its own limits: pure PTFE to 500 deg F (260 deg C), PTFE-impregnated synthetic fiber to 450 deg F (232 deg C), and quad-seal packings of PTFE with Buna-N (90 deg C), Viton (200 deg C) or EPDM (120 deg C). Bray notes that when EPDM is chosen as the seat, pure PTFE packing with an EPDM quad seal must be selected.

Face-to-face length is held to the MSS SP-81 dimension, 48 mm for DN 50 up to 76 mm for DN 300, which makes retrofit into existing knife gate positions straightforward. Approximate weights from the brochure are given below; confirm certified drawings with the factory because Bray states dimensions are approximate and subject to change.

Operators, accessories and sibling knife gate series

Topworks are designed for quick conversion between manual and pneumatic actuation, so a handwheel valve can be upgraded without changing the body. Operator options are a direct-mounted handwheel, bevel gear, double-acting pneumatic actuator, hydraulic actuator, lever or electric actuator. Accessories shown by Bray include a deflection cone, handwheel lockout, pinned lockout in open and closed positions, pneumatic fail-safe, non-rising stem, gate guard, manual override, chain wheel, a mechanical limit switch and a proximity sensor.

Choose the 740 where bidirectional sealing is needed in a lug body. The table lists the neighbouring Bray series from the product guide.

Documents and quotation

The Bray brochure is attached as the datasheet; the product page also lists an operation and maintenance manual and the recommended specification sheet. Before ordering, confirm line medium and temperature, seat and packing material, flange drilling, actuator type and supply, and whether an AWWA C520 or CRN certificate is required.

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