REIFENHÄUSER GmbH & Co

Contact: Sales Manager

Spicher Straße 46-48
53839 Troisdorf
Troisdorf,
Germany

Phone: +49 (0) 2241 / 4810
Fax: +49 (0) 2241 / 40877

Website

E-mail

 
COUNTER-ROTATING TWIN-SCREW EXTRUDERS

Counter-rotating twin-screw extruders come in two types, i.e. with conical twin screws for lower output capacities and with parallel twin screws for higher output capacities.

Thanks fo the system of counterrotating, intermeshing screws and the direct extrusion of powder, offer a number of twin-screw extruders noteworthy advantages in extrusion processes, e.g.

* Elimination of pelletising process
* Reduction in formulation costs
* Improvement in quality of end products

In the processing of rigid PVC-mixtures, in particular, twin-screw extruders are superior to the single-screw extruders, as may be seen from the following facts:

* Constant raw material feed rates at the intake end, regardless of friction factors
* Gentle heating and plasticising
* Reliable yenting og volatile constituents in raw material
* Excellent homogenisation in terms of thermal and mixing characteristics
* Pressure build-up without detrimental side effects on conveying the melt
* High output capacity at low screw speeds
* Outstanding cost-effectiveness ratio.
 
Drive unit:

The drive unit comprises a high-performance, low-noise gear with integrated torque spitter and thrust bearing in a cast casing. It incorporates design variations according to the different plasticizing systems. In the conical system, two tapered pinion serve as the torque splitter. Simple thrust cylindrical roller bearings are used as thrust bearings. With the cylindrical system, by contrast, the torque splitter consists of a multi-shaft power divider. For the thrust bearing, one single and one multiple thrust cylindrical roller bearing (tandem bearing) are used.
     
Metering

Twin-screw extruders can be equipped with feed hoppers or metering equipment as desired. By using a volumetric or gravimetric betering system, the individual spectrum of formulation can be substantially extended. Gravimetric metering, moreover, permits the continuous weighing of the raw materials and consistent running meter weight.
     
Temperature control:

Barrels are divided into heating and cooling zones according to the process technology of the individual barrel or screw section and their respective plasticising functions.
This guarantees a precise temperature profile over the entire length of the barrel. As a rule, air cooling is employed. Only in the case of machines with high productivity rates or machines that are processing extremely adherent compounds, other cooling media are used.
     
Barrel venting:

The screw channels of systems employing counter-rotating, intermeshing screws are only partially filled with material in the venting area. This allows particularly efficient venting of both conical and cylindrical screws. The vacuum unit, with separator, is installed in the extruder frame and, like all the elements requiring service, is readily accessible.
     
Operation:

Operating controls and monitoring instruments are mounted in a swivelling housing at the barrel outlet end, near the die, this facilitating efficient machine operation and product monitoring at the same time.
     
Plasticizing unit

All twin screws are equipped with a temperature control system.
Reifenhäuser offers two different systems:
*
internal temperature control functioning on the steam tube principle
*
external temperature control by means of an oil circulating system with adjustable oil temperature

For certain raw materials, Reifenhauser offers twin-screw extruders with proven, multisection parallel screws with interchangeable segments. These permit rapid, low-cost adaption to different formulations.

Conical plastificising unit

Cylindrical plastificising unit

The geometry and surface structure of the intended application and raw material formulation. Only the optiomum combination can guarantee high throughput rates at the same time as increased melt performance and reduced wear, Since the type of screw to be used depends entirely on the product, intensive discussions with the customer are essential.

CO-ROTATING TWIN-SCREW EXTRUDERS

In the Reitruder REIFENHÄUSER has developed a proven machine concept into a high per- formance core of direct extrusion lines. Whereas co-rotating twin-screw extruders have hitherto been used only for compounding and pelletizing plastics, the REIFENHÄUSER Reitruder has made direct extrusion highly marketable. Reitruders are already running with great success and high economic efficiency in

* pipe extrusion lines
* cast film extrusion lines
* thermoforming sheet lines
* foamed thermoforming sheet lines
* coating lines

all over the world.

Direct extrusion on the Reitruder saves you 20 - 30 % in raw material costs compared with running pre-mixed compounds - and you will get improved product properties as well.

Directly extruded cups, trays for ready meals and controlled atmosphere packagings show higher stiffness and stronger resistance to heat. The technology developed by REIFENHÄUSER, however, gives you even more: In addition to considerable cost saving, the processing speed in sheet thermoforming can be increased. Polymer compounding and converting into semi-finished products are done in one step only. Result: higher quality - lower costs. The high standard of engineering in the Reitruder is REIFENHÄUSER?s response to the growing demands of the market. The REIFENHÄUSER modular principle is targeted to individual custom-er objectives. Customer wishes are built in, right from the planning stage, and a tailor-made twin-screw extruder is assembled from a range of separate components. The result is an individually designed, unique machine despite the absence of any specially made components that meets all the demands the market specifically places on the direct extrusion process:

* optimised feeding of materials that tend to clog
* smooth conveying of slow-flowing powder materials, sticky masses and fibrous additives
* high, uniform throughput rates
* outstanding dispersing and homogenising action for products of consistently high quality
* precision melt temperature control and monitoring
* powerful single-stage and multi-stage extraction of volatile components ,
* extreme flexibility in processing disparate material components
* low tendency to wear on barrel and twin screws

Individual modules
 
Drive unit

The drive unit comprises a high-performance, low-noise gear with integrated torque distribution that is connected to the AC or DC motor by means of a clutch (the RZE 43 is provided with a belt drive gear).
     
Metering

Reitruders are fitted with different metering units to suit customer requirements. Employing volumetric or gravimetric metering units significantly extends the individual bandwidth of the formula-tion ranges. In addition, gravimetric metering ensures continuous weight monitoring of the raw materials and a constant melt throughput.
     
Temperature control

The division of the barrel into heating and cooling zones matches the individual barrel and screw zones to the production process. This ensures a precise temeprature profile over the entire length of the barrel. The temperature of each barrel zone is controlled separately. Heating is derived from resistance heating elements, cooling from the use of air or fluid media as heat dissipators.
     
Barrel venting

On the system, with its co-rotating, closely intermeshing screws, the screw channels in the vent-ing area are only partially filled with material. This permits especially efficient single-stage or multi-stage venting. The vacuum system with separator is installed into the extruder frame and, like all serviced elements, it is easily accessible.
     
Control

The control and monitoring unit is readily accessible and easy to watch. This ensures that the machine can be reliably operated and monitored at the same time.
      
Wear-resistant barrels and screws

The most important component in every Reitruder is the barrel and screw assembly. Its quality and finish, carefully matched to the complex interaction of barrel, screws and raw material, exert a significant influence on the service life of the Reitruder and the high and consistent quality of the final product. The design of the Reitruder is based on the modular construction principle. Barrel and screws can thus be assembled in any combination to make up a plasticising unit with raw material feeding, ventilation or gas extraction. The two co-rotating, closely intermeshing screws are arranged in parallel and are self cleaning. They are divided into segments thus enabling the screw geometry to be adapted to individual applications. The order in which the kneading and mixing components are arranged can be freely selected depending on the product formulation. The positive engagement of the screw segments on the screw shaft enables individual segments to be easily replaced and thus ideally adapted to the material to be processed.
 
Single screw extrusion
THE STARTING POINT OF HIGH-QUALITY PRODUCTS
   
As the heart of any modern extrusion line, the extruder is of utmost significance to the quality of the final product.


Single-screw extruders are used primarily for plasticising pellet-type raw materials.

REIFENHÄUSER supplies extruders with smooth or grooved feed zone that can be combined with a venting system.

REIFENHÄUSER has divided its extruder range into two series:

* RH - with high-level plasticising unit
* RT - with low-level plasticising unit

Decades of experience in development make REIFENHÄUSER extruders a reliable partner for the rational production of high-quality products.

Single-screw extruders represent the core of various extrusion lines for the manufacture of:

* blown films
* cast films
* thermoforming sheets
* sheets
* spinbonded nonwovens
* synthetic fibres
* pipes
* profiles

or in

* repelletising lines
* recycling lines

 
Blown Film Extrusion Lines from Reifenhäuser
   
Modular design

* Extruder
* Forming and cooling equipment
* Sizing and haul-off equipment
* Winder
* Line automation system
* Accessory systems, e. g. metering unit

Other Applications

Industry packaging
 
shrink film

stretch film

bag film

container liners
 
Consumer packaging
 
packaging film for frozen products

shrink film for transport packaging

food wrap film

packaging bags

form, fill and seal packaging film
 
Laminating film
 
laminating of aluminium or paper

used for packaging for example milk or coffee
 
Barrier film
 
made of raw materials such as polyamides and EVOH acting as an aroma or oxygen barrier

used for packaging food, e. g. cold meats and cheese

films for the packaging of
medical products
 
Agricultural film
 
greenhouse film

crop forcing film

silage film

silage stretch film