Through the simple construction and the great variation in materials, butterfly valves are broadly applied for various media such as water and air, but also chemical and aggressive media. Butterfly valves are used for open/close purposes, but are also suitable for simple regulating purposes,especially designed for the use in following markets:
- Maritime sector
- Heating and air treatment
- Chemical and Petrochemical industries
- Machinery manufacturing
- General industry
- Potable water piping systems
- Water treatment plants
Butterfly valves feature the following four general design options:
This type is suitable for mounting between flanges acc. to DIN or ANSI
This model is suitable for mounting between flanges acc. to DIN, and can also serve as dead-end valve as reduced pressure.
This type is suitable for mounting between flanges acc. to DIN or ANSI by means of the tapped holes. Also can serve as a dead-end valve at maximum operating pressure.
This type is connected with the counterflanges in the pipe sections by means of the two cast flanges, used as ship side valve according to the rules of various classification bureaus.
An additional characteristic of butterfly valves are the various different types of liner. For example, there are butterfly valves with a bonded or a replaceable rubber liner. In these cases, the medium only comes into contact with the lining and disc of the valve.This means the body vcan b manufactured from a less expensive material such as cast iron.
For corrosive media, the lining can also be manufactured from PTFE.
Rubber-lined butterfly valves and PTFE-lined butterfly valves are in general suitable for operating pressures up to around 16 bar, and temperatures up to a maximum of 120 degrees Celsius (PTFE ± 200 degrees Celsius). For higher pressures and temperatures or media for which normal rubber-lined butterfly valves are not suitable, High Performance butterfly valves can be used. This type of valve can be made with a PTFE seat, optionally in fire safe version, or with a metal sealing ring. Because of the fact that with High Performance butterfly valves the body comes into contact with the medium, a careful choice of suitable body material is needed. The body can be built standard in steel or stainless steel.
For the butterfly valves mentioned above, various constructions have been designed to enable a perfect seal. These are:
- Centric construction, for rubber-lined valves.
- Excentric construction, for rubber-lined butterfly valves, lower torque, less friction.
- Double excentric construction, for High Performance butterfly valves, suitable for harder sealing materials such as PTFE and metal.