Butterfly Valve

Industrial butterfly valves regulate the flow in closed pipe systems. Similar to a gate, a disc inside the valve opens and closes to stop the flow. Their main task is to create one of two states, ‘open’ or ‘closed’, but not to throttle the media. Alternative shut-off valves are designed for this purpose. Our needle valves also allow for very precise control.

If you want to buy a butterfly valve, guidelines in Germany stipulate a certain performance. From a mechanical point of view, valves today function very similarly. At the centre is a disc that blocks the flow. This is achieved by rotating it transversely to the direction of flow. In a centric design, the pivot point for this is located in the centre. Double eccentric solutions shift this point further along the axis of the pipe and are not aligned with the centre.

The difference lies in how it is fitted to the pipework. A wafer-type butterfly valve is clamped directly between two mating flanges on the pipework without its own flanges and held in place by through bolts – it is compact, lightweight and cost-effective. A flanged butterfly valve (lug design) has its own integral threaded holes at the ends and can be bolted to a flange on one side using stud bolts, allowing for a detachable connection on each side. The lug design is therefore particularly suitable for dead-end service – i.e. wherever one side of the pipeline needs to be isolated from pressure without dismantling the opposite side. Both designs are available from stock at FERGO as part of the Fergo butterfly valve range.

The material of the seat ring determines the media resistance and temperature limits of the butterfly valve:

• EPDM – For water, hot water, steam, diluted acids and alkalis, as well as media used in water treatment and the food industry. Not suitable for oils. Up to approx. 120 °C.

• NBR (nitrile) – For mineral oils, fuels, greases and oil-containing media. Not suitable for hot water or steam. Up to approx. 80 °C.

• PTFE – Virtually universal chemical resistance to aggressive acids, alkalis and solvents. The first choice in the chemical and pharmaceutical industries – available as a PTFE butterfly valve.

• FKM / Viton® – High resistance to aggressive chemicals, solvents and elevated temperatures up to approx. 180 °C. Ideal for demanding process media.

If you are unsure about media compatibility, the FERGO team will be happy to provide individual advice.

The FERGO butterfly valve range covers a very wide spectrum of nominal sizes and pressure ratings:

• Nominal sizes – DN25 to DN1200 (depending on the design; concentric valves up to DN1200, double‑eccentric and DVGW valves up to DN300)

• Pressure ratings – PN6, PN10 and PN16 for standard industrial applications; higher pressure ratings (PN25, PN40) for double‑eccentric versions

• ANSI/ASME – Class 150 for inch‑standardised piping systems, particularly in the international and American markets

• Face‑to‑face length – Wafer type according to ISO 5752 short series; Lug type for dead‑end service

All butterfly valves are available from stock. Use the product configurator to filter specifically by nominal size, pressure rating, seat ring material and body material.

That depends on the desired effect. As the name suggests, non-return valves are primarily designed to prevent backflow of media. They operate passively and close automatically when the flow is appropriate. An electric or pneumatic butterfly valve with a drive can also operate automatically, but still switches actively. Depending on the design of your pipes, it may even be worthwhile to use a combination of both valves.

This is generally difficult to answer and depends on the local conditions. As a rule of thumb, you can use the size as a guide: above a certain nominal diameter, we clearly recommend butterfly valves for pipelines. A ball valve, on the other hand, can be ideal for smaller systems. Both types are suitable for flow control and reliably ensure interruptions without leakage. Simply get in touch with us. We will help you find the right product.

Our stainless steel or ductile iron butterfly valves are compact, durable and designed for use in a variety of industries. They are also usually more affordable than comparable gate valves in similar segments. More importantly, however, a butterfly valve that complies with DIN standards performs its task to the utmost satisfaction. The valve blocks the flow reliably and, above all, quickly. The automatic version is particularly impressive.

A double‑eccentric butterfly valve – also known as a high‑performance butterfly valve or double‑offset butterfly valve – differs from a concentric butterfly valve by two geometric offsets of the rotation axis. First, the shaft is offset behind the seat plane, and second, it is shifted laterally from the pipe centre. This causes the disc to immediately swing out of the seat when opening, rather than rubbing against it. The advantages over concentric valves are reduced seat wear, longer service life and the ability to use metal seats. This makes the double‑eccentric design particularly suitable for higher pressures (PN16 to PN40), elevated temperatures, frequent actuation cycles and media that would damage soft elastomer seats – for example steam, hot gases, abrasive media and aggressive chemicals.