Volkmann CarpetTwister

Two-for-One Twisting Machine

Why are carpet yarns twisted on Volkmann Two-for-One twister ?
The reasons are essentially two-fold:

In order to produce a stable, open pile thread under conditions of maximum cost efficiency. This applies particularly to BCF filament utilized as single yarns for the manufacture of particularly thick carpets by the tufting process. The upgrading process used in this case is generally referred to uptwisting.
or
In order to manufacture a particularly durable thread for woven carpets. In this case, preference is given to staple fibres, wool or polyacrylate yarns, or polyamide, polypropylene and various blends specifically devised for the manufacture of carpets. The process used in this case is classic Two-for-One twisting.

The particular quality and the high productivity of the twisting process are very much in the foreground in such applications.
The Two-for-One twisting process is characterized by the fact that each mechanical spindle revolution imparts two twists to the yarn. This ensures, in particular, a particularly effective up-twisting process for single yarns.

The yarns are economically twisted to the degree required to give an even pile. Dense, uniform, voluminous carpets are particularly popular because of their attractive visual appearance, durability and service qualities.

Yarn path with Two-for-One twisting

Two feed package methods are possible.

Assembly wound package
The yarn ends have been (pre)-assembled onto one yarn package.

The yarn ends are being unwound from the feed package by passing through the flyer.
The flyer prevents the yarn from dragging over the edge of the feed package and assures the unwinding from the yarn package.

Direct feed package
Two superposed yarn packages, each with one single yarn end.

The untwisted feeding arrangement is placed into the stationary spindle pot.
The yarn passes from the feed package to the apex of the spindle and enters the yarn channel and multi-tension device. It then enters the spindle and exits at the spindle rotor.
The yarn follows the groove of the reserve disc and balloons around the stationary spindle pot. The position of the balloon guide, and on some machine models the balloon limitor determines the size of the yarn balloon.
The yarn then passes around the deflection rolls of the yarn sensor to the pre-take-up roll. Finally the traverse guide lays the yarn onto the rotating yarn package driven by the take-up roll.