A second life for the Rieter K-frame


Rieter K-Conversion – Upgrade of the K-Machine to the Swinsol Mechancial Compact Solution

Introduction Rieter K-frame

It is now possible to spin short staple fibers with a mechanical compact system upgraded to the Rieter machine and achieve the same yarn quality with significantly reduced costs (same cost as conventional spinning) on the Rieter K-frame. Compact spinning was introduced as a trial system in 1995. Later in the year 2000, Rieter introduced an innovation in the air guide providing more fibre compactness. It was called K44-Com4, the Rieter K-frame and it uses suction compact technology. If clean long combed fibers are used, the K-system delivers good yarn results for fine yarns. However, on the sourcing market there are by default less long fibers available. Especially cotton has – by nature – shorter fibres. If the high quality material is not availabe, by our experience, the suction compact will lose its fine-yarn advantage. In reality the K-frame is often used to spin coarser counts and short carded fibers. Pneumatic (suction) compact causes higher cost of material and additional energy consumption. Our upgrade can be used to give the Rieter K-frame a second life to save resources, energy and costs for expensive spare parts. Therefore the economical effect and the cost benefits are significant.

The Rieter K-frame requires a high cleaning effort (cleaning the air guides) and vacuum. In contrast, a mechanical compact upgrade is maintenance friendly and only uses half the amount of vacuum for suction. With the Recompact 3.T upgrade the spinner has the benefit of low costs for spare parts. A new drum cylinders every 10 years for example can be as expensive as a new chinese ring spinning machine. Additionally the low energy consumption and the fast maintenance are the main benefits. For our valued customers who own the K-machine, we want to offer an upgrade from the K-frame suction compact to a mechanical compact system. We offer a patent pending solution to upgrade the Recompact 3.T unit on the K-machine, which provides the customer 18mm controlled traversing and significant savings on spare part and vacuum costs.


Geometry of Recompact 3.T for K-frame upgrade

The following Geometry has been changed. On the left side you see the original drafting unit for vacuum compact and on the right side the new drafting unit for mechanical compact.

The drum cylinder has been replaced by the bottom roller. We inserted a new multichannel compactor, replacement delivery roller, a modified cradle and buttom nose bar and the swinsol double condenser. The parts are mechanical and the suction is significantly reduced.

Scope of Supply

This is the complete scope of supply provided and installed to change the Rieter K-Frame to the Recompact 3.T mechanical compact system. The system can be integrated, keeping some of the original Rieter parts in place. It will be modified with these parts:

Foucs on conversion to mechanical compact

The Rieter K-Frame is updated with the latest Recompact 3.T compacting system. It uses 3 channels for the roving aswell as controlled traversing and 18mm of the cots width, making the most out of your production. In the process of the modification from the suction compact to the mechanical compact system for the Rieter K-machines, the focus has been on:

  • Modify as few parts as possible – to reduce costs
  • Provide a user friendly solution
  • High compact yarn quality
  • Reduce suction
  • Same costs as conventional spinning


Same yarn quality with lower costs

We are constantly running several test and we achieve the same yarn values as the Rieter K-frame. Depending on the yarn count, sometimes some values can be even better. You can compare the test results in the table below.

Upgrade & Replacement parts

We have focused on keeping the costs for the conversion low, so we implemented a cost effective solution. The conversion of the drafting device is shown in the pictures. The position of the original cylinders is unchanged, but the drum cylinder is replaced with a bottom roller cylinder. A new bearing slide was invented for an optimal bottom nose bar position. The hole between the bottom nose bar and the aprons has been closed with an intermediate piece, so that the apron guiding is in an optimal position. The front top roller is set in a new position and composed with saddle inserts. The position is designed, so that the necessary pressure for spinning is achieved. The top roller holder stabilizes the position of the delivery roller. We are using the original spring in the front of the toparm to achieve the required load on the delivery roller. The cradle is the same, except for minor modifications. The original suction tube is used, only the support is a new piece in order to guarantee the optimal distance between delivery rollers and spinning areal. During tests, we found no difference in yarn quality between mechanical compaction and vacuum compaction. With this conversion, we give the Rieter K-machine a second life. The Upgrade saves valuable resources and significantly reduces energy costs for the yarn production of the machine.


The only solid controlled traversing unit you will ever need

Controlled traversing is a principle known from regular spinning which we use and innovate in our Recompact Units. In order to extend the lifetime of cots and aprons, the channel or roving path is changed in intervals. The mechanical compact spinning unit Recompact has this innovative feature build in. This means you can travers the roving between 3 channels and control the behaviour and loss of quality in the yarn at any given time. This lets you use 18mm of the cots and extend the lifetime of cots and aprons. We adopted this system because of the simplicity and the extended lifecycle while reducing workforce, labour costs, energy consumption and material costs. The principle works like demonstrated in the graphic below:

Controlled traversing in mechanical compact spinning


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Nik Istrefi











Swinsol AG

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