Butterfly Valves

What is a butterfly valve?

A butterfly valve blocks the flow of a liquid in a pipeline. It is one of the simple shut-off and control valves used in pipeline systems for media such as gases or liquids. The flow can be controlled and shut off by means of a rotating disc. Smaller nominal sizes can be operated by hand by means of a lever. In the case of butterfly valves with larger nominal sizes, operation is by means of a hand crank with gear, drive motor, a hydraulic or pneumatic drive. One difference to gate valves is that when open, the valve has the highest flow resistance. One advantage is that this means that a butterfly valve requires very little space.

Which butterfly valves are available?

Where are butterfly valves used?

The following list will help you to get an overview of the areas in which butterfly valves are used:

  • Chemical industry
  • Food industry
  • Water treatment plants
  • Building services

Double Flanged Butterfly Valve

Article number

Article Description

The article 04-028N is a double flanged butterfly valve with a split shaft. In contrast to the lug butterfly valve, or the wafer butterfly valve, the two flanges make it much easier to install and de-install. With a closed disc, it’s no problem to close/seal the pipe from one side for maintenance or repairs, without medium leakage. The flange holes aren’t threaded and are secured at the counter flange of the piping system using a screw, washer and nut. The flange holes are drilled according to DIN EN 1092 PN10/16.


This version of the Double Flange Butterfly Valve is activated with a notch lever. We offer these in the nominal diameters DN50 to DN200. From a higher nominal diameter, we sell these valves with a worm gear (04-030N). Of course, the smaller sizes can also be operated with worm gears.


The valve is suitable for seawater, the housing is made from nodular cast iron. The disc is made from aluminum bronze. The seat is, in this case, made from NBR. This seal can withstand temperatures up to +80° and is oil resistant. For higher temperatures EPDM is used, which can withstand temperatures of up +120°, although it is not oil resistant. An FPM seat can also be implemented when the valve temperatures are up to +150° and used with oil-based mediums.

Pipe Classes

This double-flanged butterfly valve is a pipe class 1. Mostly used on ships, particularly on the outer shell. Therefore, an acceptance test is usually carried out in the form of a pressure test. The certification is carried out by a classification society.

Type of connection: Flanges according to DIN EN 1092 PN10/16

Housing Material: Nodular Cast Iron

Seal: NBR