Privet Double DumperŪ

Privet Double DumperŪ installed
at a pulp mill.

Privet • Double Dumper


The feeding member of the Double DumperŪ is spherical, in the same way as the ball of a ball valve. However, it does not have a through-flow opening. Instead, it has two feeding spaces, one facing the process, the other facing downstream.

Operating principle

When the upper feeding space is filled with reject, the feeding member rotates 180 degrees, allowing the reject to drop into the downstream piping. The empty feeding space that is now facing the process is ready to collect new reject. When it is full, the feeding member rotates 180 degrees in the opposite direction. The change in turning direction divides the erosion equally between both sides, extending the service lifetime of the dumper. The maximum amount of reject dumped with each stroke of the feeding member equals the volume of the feeding space, plus some additional fluid.


The capacity of the Privet Double DumperŪ depends on two variables: the nominal size and the operational frequency. The frequency needs to be adjusted to the needs of the process, as with a conventional junk trap. For example the feeding volume of a 6-inch Privet Double DumperŪ is about 1.4 litres. With an 8-inch feeder in the same 6-inch line, the volume increases to about 3.3 litres.

Design alternatives

The Privet Double DumperŪ product family is modular. It may be fitted with different seats, such as PTFE/metal or metal. Its tightness and capability of handling impurities are comparable to those of a ball valve with the same seat designs. The type coding system describes the standard design alternatives.

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