Resilient-seated wafer type butterfly valve with a lever operator, offered with a cast iron or stainless steel disc. The body is clamped between two pipe flanges by through bolts and is used for isolation and coarse throttling on water and general service.
Prices on request. Contact us for availability and quotations.
A wafer type butterfly valve is a flangeless body clamped between two pipe flanges by bolts that pass right through. A disc on a shaft turns a quarter of a revolution from fully open, where it lies edge-on in the flow, to fully closed, where its rim is pressed into a resilient liner that also covers both faces of the body and acts as the flange gasket. Face-to-face length is short - a fraction of a gate valve of the same bore - which is why butterfly valves dominate large-bore water and services lines.
Because the body has no lugs, a wafer valve is held in compression by the pipework and both companion flanges must be present. It is not suitable for end-of-line duty: remove the downstream flange and there is nothing holding the valve in the line. Where a line has to be broken with the valve closed, the lug pattern is the correct choice.
The valve type is covered by MSS SP-67, by EN 593 and, for concentric-disc cold-working-pressure valves, by API 609 Category A. The disc is the part that decides service compatibility: cast iron is adequate for clean cold water, while a stainless disc is specified where the medium is aggressive, aerated or intermittently dry. The elastomer of the seat decides the rest - EPDM for water and dilute chemicals, nitrile for oils, and neither is a general-purpose answer.
When ordering, state the nominal size, the flange standard and rating the valve must sit between (EN 1092-1 PN10/16 or ASME B16.5 Class 150 - the bolt circles differ), the disc material, the seat elastomer, and the operator. Confirm the working pressure and the temperature limit with the supplier; neither is marked on the valve in the photograph.
| Body Style | Wafer (flangeless): the body is clamped between two companion flanges by through bolts. Both flanges must be in place - the valve is not suitable for end-of-line or dead-end service |
|---|---|
| Disc Material | Cast iron or stainless steel; the unit photographed has a bright stainless disc |
| Seat | Resilient elastomer liner covering the body bore and both body faces, doubling as the flange gasket. The elastomer grade (EPDM, nitrile, etc.) decides fluid compatibility and must be specified |
| Operator | Lever with a notched locking plate, giving fixed intermediate positions between fully open and fully closed |
| Face-to-Face | API 609 Category A lug- and wafer-type, metal-to-metal across body flats: 43 mm at NPS 2, 46 mm at NPS 2.1/2 and NPS 3, 52 mm at NPS 4, 56 mm at NPS 5 and 6, 60 mm at NPS 8, 68 mm at NPS 10, 78 mm at NPS 12 and 14, 102 mm at NPS 16, 114 mm at NPS 18, 127 mm at NPS 20, 154 mm at NPS 24, rising to 276 mm at NPS 48. Varies with size - do not quote a single figure |
| Flange Standard (to be specified) | The drilling the valve is designed for must be stated - EN 1092-1 PN10/16 or ASME B16.5 Class 150. The two are separate systems: at DN50 / NPS 2 the EN bolt circle is 125 mm and the ASME bolt circle is 120,7 mm, with M16 bolts against 5/8 in UNC. They are not interchangeable |
| Closing Direction | Clockwise |
| Product Standards (valve type) | MSS SP-67 (flangeless/wafer, single-flange/lug and flanged-end butterfly valves, NPS 1.1/2 - NPS 72); EN 593 (metallic butterfly valves, wafer, lug, flange and butt-welding ends, PN 2,5 - PN 160 and Class 150 - 900, DN 20 - DN 4000); API 609 Category A (manufacturer's rated cold working pressure valves, usually concentric disc and seat, NPS 2 - NPS 48 for ASME Class 125 or 150 bolting patterns) |
