Rotary joints series 7950 for extruder construction

The slender rotary joints from the HAAG + ZEISSLER 7900 series have proven themselves over a period of many years. At the request of our customers with the 7950 series a compact rotary joint has now been designed especially for cramped mounting spaces in extruder construction.

Extruders are screw presses that homogenise solid to viscous masses under high pressure and high temperature and press them out of a specially shaped opening. Apart from the food industry, the main sales market for extruders is the plastics industry. For example: pipes, profiles, bottles and much more can be manufactured from plastic by means of extrusion. The plastic granulate or powder is melted by means of heating in the screw cylinder; so called plasticized. In order for the plasticized plastic to solidify again after moulding, it must be cooled. This can take place by means of cooling channels integrated in the extruder cylinder, through which a cooling medium flows – for example water under pressure. The cooling medium is fed in through a rotary joint, through which the medium flows into the rotating cylinder.

In extruder construction the rotary joints are normally integrated in cramped installation situations. For that reason slender and compact sizes are called for. On the basis of the proven sealing system of its 7900 series, HAAG + ZEISSLER has now developed a compact rotary joint, taking into account economic aspects. In its robust, vibration-proof sealing cartridge system CD-Cartridge-Design the rotor, bearings and the stationary and rotating sealing parts are combined in a pre-assembled unit. This quick-change cartridge system can be individually and easily exchanged. In this way the machine downtimes can be minimised.

The housing of this rotary joint is made of anodised aluminium. The weight of the housing has been reduced by 60% through the choice of this material. This minimises the oscillating mass at the shaft end and the service life of the rotary joint is prolonged.

HAAG + ZEISSLER consistently manufactures the 7950 series only in Germany. The rotary joints – made in Germany – are developed in the factory in Hanau with the goal of individually optimising the product for the complex requirements of the machine user.