Groz-Beckert KG

Newsletter 1 | 2011

Hydroentanglement with jetstrips –
Using the full power of water

Water is essential to life - and it would be impossible to imagine this modern technical world without hydropower. One example is the technology known as hydroentanglement, where incredible power can be derived from the pressure of water alone. Highly sensitive technical products are required by this technology. Learn how precision tools and services from Groz-Beckert can provide you with tailored support.

Groz-Beckert – Your partner for hydroentanglement

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It was in 2004 that Groz-Beckert began working in the jetstrip production sector. Today the company is one of the world's leading manufacturers. The product range comprises jetstrips with overall lengths of 200 to 5,700 mm and with 40 to 14,500 jets in one, two, three or four rows. The diameters range from 0.08 to 0.19 mm.

In general, jetstrips are highly sensitive precision tools, and using them requires special care. Damage to the jets in the micron range that are invisible to the naked eye can still influence the physical properties of the spunlace product. In extreme cases the jetstrip has to be exchanged.

With precision and expertise, Groz-Beckert provides jetstrips in all the usual dimensions and hole geometries. The production method used guarantees an absolutely burr-free product with precise, positive and uniform jet geometries. The emphasis is on minimal wear and tear and on lowest possible contamination of the jetstrip.

A technology with high standards

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The hydroentanglement method is based on the swirling of individual fibres by means of a large number of very fine water jets. To create these, water is distributed evenly in a nozzle manifold at a high pressure of 30 to 420 bar across a width of 500 to 5,700 mm - and guided through the jet-holes of a jetstrip located inside it. An average of five to six nozzle manifolds are used per unit. The jets of water created in this way, with a diameter of between 0.08 and 0.19 mm, hit the fibrous web at a speed of up to 280 m/s. That is equivalent to 1,008 km/h. The fibres are swirled and a compressed nonwoven is created. The entire water throughput of an average unit with six nozzle manifolds and a pressure of 220 bar amounts to 3.6 million litres. This is equivalent to 3,600 m³ in 24 hours. In comparison, an average household uses up between 175 and 200 m³ of water each year.

Needling v. Waterjet

Although both technologies come under the heading of mechanical entanglement, there are only a few points in common. In most cases the same fibres are used, but depending on the application - when using synthetic filaments such as Bi-component fibres, for instance - the fibres can additionally be split during hydroentanglement. This enables specific product properties such as "textile roughness" or impermeability to ultraviolet light.

During needling, surface weights from 50 to 5,000 gsm are created, while during hydroentanglement the weights used are generally in the region of 15 to 600 gsm. Surface weights are not the only difference, however. In contrast to needling, where despite good entanglement a defined volume is possible, no defined volume can be created with hydroentanglement. The two technologies also differ where production speed is concerned. Needling takes place at a maximum of 30 to 50 m/min, while with hydroentanglement production speeds of up to 300 m/min are possible.

Hydroentanglement and needling are not direct competitors. They serve identical but also differing fields of application. This becomes especially clear from the main areas of application for hydroentanglement: 

 

 

Examples

Medicine

 

Surgical apparel (disposable operation clothing)

Hygiene and household

 

Nappies, wipes

Technical applications

 

Filter and insulation nonwovens, synthetic leather

The problem: wear and tear – the solution: jetstrips with GEBEDUR® coating

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After only a short period of use with the jetstrip, prematurely rounded capillary edges can lead to turbulence in the water jet and thus to irregularities in the water curtain. Related fluctuations in the energy transfer of the nonwoven are reflected in the form of irregular stripe markings on the finished end product.

To solve this problem Groz-Beckert has developed the GEBEDUR® jetstrip. GEBEDUR® products from Groz-Beckert represent a consistent further development that goes far beyond what is standard. HyTec® GEBEDUR® jetstrips have a long service life and simultaneously high quality.

The longer lifetimes are made possible by the reduction of capillary-edge wear. Parallel to this, the coating ensures that product properties remain lastingly homogeneous. The jetstrip is more resistant to external influences such as scratches, impacts or damage from being dropped. 

 

The problem: contaminated water – the solution: process-water analysis

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In the production of spunlace products, the quality of the process water plays a decisive role. Its consistency influences the service life of various machine components and also that of the jetstrips. Moreover the process water has effects on the quality of the end-product, especially in the production of hygiene articles. This is why hygienically pure water is very important. Water, a very multi-faceted medium, can occur in acidic, alkaline, fully or partially desalinated form. It can also contain microorganisms, metallic particles and other inorganic substances in various concentrations. Determination of water quality involves not only pH value, water hardness and chloride content but numerous other parameters as well. Groz-Beckert supports you in establishing precise knowledge of the process water you use. As part of comprehensive laboratory analysis, your process water is examined with regard to important hydrochemical parameters. In addition you can also find out about ways to improve the quality of your process water. 

The problem: contaminated jetstrips – the solution: consistent purification

Fibre residue, rust, metal particles, chalk sediment and chemicals in the process water - as well as pollution in the process water - influence more than just the quality of the end product, they also leave traces in the area of the jets. The resulting deposits inside the jets steadily narrow the jet diameter and obstruct water flow. Contaminations in the entry area of the jet opening have a detrimental effect on formation of the water jet and thus of the water curtain. As a result, the physical properties of the spunlace product are affected.

Jetstrips should therefore be professionally cleaned at regular intervals. On the one hand, deposits have to be removed, while on the other the sensitive structure of the jetstrip has to be protected. Aspects such as work safety and environmental protection also play an important role. Groz-Beckert recommends the use of a clearly defined cleaning process.

In everything relating to hydroentanglement, Groz-Beckert is your reliable and competent partner. Take advantage of our individual, tailored consulting and our range of products to fully optimise your spunlace production.