Arnature; shut-off valve

A shut-off valve is a technical component that opens or closes the flow of solids, liquids or gases in pipelines. It is crucial that the mechanical operation takes place outside of the medium to be controlled. This is what distinguishes it from a flap or door.

In bulk materials processing technology, shut-off valves must fulfil special requirements:

• They must function reliably over long periods, even when the bulk solids are abrasive.
• They must have a low flow resistance when open.
• They must be as gas-tight as possible.
  • a) to the (outer) atmosphere side
  • b) to the closed product side

If the shut-off valve is located below the powder mixer, there are some particularly important features:

It must seal the mixing chamber without dead space, it must be dust-tight, and it must not open unintentionally during the mixing process.

If the mixer is also a vacuum mixer dryer or a synthesis reactor, another property is added: the valve must close and seal gas-tight against gauge pressure and vakuum.

These requirements make valves in the bulk materials industry complex and expensive.

Various types of shut-off valves are used in amixon^® mixing systems. Rotary valves are located above the mixing chamber; slide valves are only used at the express request of the customer. Segmented ball valves are used in vacuum mixing dryers and synthesis reactors. They are then equipped with inflatable seals.

One example of an innovative shut-off valve for amixon^® mixers is the DosiFlap^®. This space-saving solution functions both as a dead-space-free shut-off valve and as a dosing device. It allows precise metering of the outgoing mixture, which is particularly advantageous when filling big bags or bulk material containers. In addition, the DosiFlap^® has a very hygienic design.

Bulk materials can have very demanding properties. amixon^® therefore conducts long-term tests in the technical centre to optimise function and wear.