BHS-Sonthofen has decades of experience and comprehensive process engineering know-how in the manufacture of plastic intermediates. Our rotary pressure filters (type RPF) and indexing belt filters (type BF) offer you high throughput rates and process reliability over the long term. The total operating costs are very low, despite achieving exceptional product quality.
Whether you are processing polyamides, terephthalic acid (PTA), aramids, polymers, bisphenol or other plastic intermediate products: Continuously operating high-performance filters deliver high product quality due to the excellent washout quality they provide. The filters have a long service life, are built for robust use and ensure economical plant operation thanks to the low maintenance and energy costs they incur. Operating temperatures of up to 160 °C with the rotary pressure filter and filter surfaces of up to 100 square meters with the indexing belt filter go a long way toward ensuring efficient production.
BHS-Sonthofen leads the market in this field. A large share of the global production of terephthalic acid, better known as PTA (purified terephthalic acid), passes through BHS filters. Our high-performance filters are used for this purpose across the world.
Often in the production process for plastic powders, a solvent such as methanol or alcohol is used, which then has to be completely evaporated again at a later stage. Depending on the consistency of the product, evaporating the solvent is not always particularly easy and the drying process often finishes with residual moisture content in the range of 3% - 5%.
At this point, evaporation has to be supported by means of adding pre-heated nitrogen, dry-saturated steam or hot air, the so called stripping process, in order to achieve a residual moisture content of 0%. BHS supplies a continuous stripper especially for this problem formulation in an ATEX-conforming design, with a special agitator, which supports the flow of the plastic powder with the carrier medium, but also serves to guarantee heat transfer by means of a cylinder jacket.
Due to the geometry of the agitator, a high level of re-mixing is achieved and the retention time in the dryer is increased. This guarantees a constant temperature and humidity in the entire dryer as well as a homogenous and dry end product.
In order to increase the production output of extruders and injection moulders, the flow and processing characteristics of plastic granules has to be modified. Especially for polyamides (PA) and polystyrene (PS) this occurs by means of powdering (coating) with powder additives. In doing so, two different methods are employed. The pure dry mixing of plastic granules with the powder additives and the moistening of plastic granules with liquid binding agents / powder additives. With both methods it is necessary to create an extremely homogenous end-product with very high repeatability, in order to guarantee a sustained product quality, as any deviation in quality immediately shows up as a flaw in the surface during the subsequent processing in the extruder or the injection moulding machine.
The BHS horizontal mixers achieve best results in terms of homogeneity under high throughput performance. As the mixing and detention times in the mixers are very short, a fast moistening of all plastic granules with the binding agent and additives without product damage is vital. For this reason the machines are adapted to the corresponding customer’s requirements and are designed for gentle or turbulent mixing.
Superabsorbers (SAP, superabsorbent polymers) are plastics, which are able to absorb 1000 times their own weight in liquid. The main areas of application are baby nappies as well as products for female hygiene and incontinence care.
Continuously operated BHS horizontal mixers are a superior solution for this process. Turbulent mixing with the adjustable BHS paddles enables the addition and dispersing of liquid additives into the mixer. The upstream process stage for moistening the SAP powder is thereby saved. The customer achieves a highly efficient production process with several process steps in one machine, a high throughput of the entire system and a high SAP product quality.