Afsluiter

Afsluiter is a general term used in Dutch for a device that can close off or isolate the flow in a pipeline. An afsluiter is designed to stop, regulate, or interrupt the passage of liquids, gases, or slurries. They are deployed in a wide range of applications, including water supply, district heating, gas networks, and industrial processes. Afsluiters can be operated manually or automatically, with actuation driven by electric, pneumatic, or hydraulic systems.

The basic function of an afsluiter is to move a closure element into or out of the flow path. The closure element can take several forms, such as a disk, ball, wedge, or sliding gate, and it seats against a corresponding valve seat to form a tight shutoff. Common configurations include globe-type (linear motion), gate-type (rising or sliding gate), ball-type (rotary closure), and butterfly-type (rotating disc). The choice of design depends on factors such as flow characteristics, required shutoff tightness, pressure, temperature, and the nature of the fluid.

Materials and construction vary according to application. Bodies are typically made of metal alloys suitable for the operating environment, with seals and bearing surfaces in elastomers or plastics like PTFE. Corrosion resistance, chemical compatibility, and mechanical durability are important considerations. Afsluiters are rated for specific pressure and temperature ranges and are often selected in conjunction with piping codes and industry standards.

Installation and maintenance emphasize safe operation and reliability. They should be correctly oriented, supported, and protected from environmental damage. Before maintenance, systems are depressurized and drained as required. Regular inspection of seals, stems, and actuators, along with timely replacement of worn parts, helps maintain effective shutoff performance.