I dag fremstilles chokolade, chokoladebarer og en række praliner industrielt. Ikke desto mindre kræver processen med at lave chokolade stor knowhow og kan kun udføres effektivt ved hjælp af moderne systemer. Innovative producenter - som Nestlé AG - bruger f.eks. Dobbeltskruepumpen fra KNOLL MB til at plastisere store blokke af chokolade.
After adding cocoa paste, cocoa butter, powdered milk and sugar, the mix is heated to a temperature of over 40 degrees and then slowly cooled to give the chocolate its delicate smoothness, smooth texture and shelf stability. At Nestlé, the chocolate is poured into blocks measuring 500 x 300 x 150 mm and stored in a cooling room at 12°C before being processed into various chocolate fillings.
To be able to mix this chocolate paste with nuts, raisins or other ingredients, the hard blocks must first be softened. In the past, they were stored in a warming room for several days at 28°C for this purpose. They could then be blended with other ingredients in a mixer, homogenised and, finally, fed into the extruder for final processing into pralines and other chocolates.
Double screw pumps are able to plasticise solid blocks
Today, chocolate pralines take less time to make. Using innovative pump technology delivered by KNOLL, the 12°C chocolate blocks can now be processed directly, thus eliminating the need for preheating in the warming room and all the transportation this involves. This makes the production process more flexible, timesaving and efficient. This gain in productivity partly originates from the KNOLL double screw pump, which has the ability to process and plasticise solid blocks of chocolate even at very low temperatures. The hard blocks of chocolate are transformed into a viscous mass which can subsequently be conveyed even large distances to the extruder by high-pressure KNOLL MX progressing cavity pumps. The extruder squirts the chocolate filling into the desired shape before the confectionary is finally coated with chocolate and decorated, then cooled and finally packaged.
I hjertet af en dobbelt skruepumpe som denne er en fuld skrue og en åben skrue, der intermesh. Dette skaber en tvungen fødeffekt, så alt, hvad der kommer ind i pumpen, udføres pålideligt. Formation af ruller forhindres ved at låse skruerne sammen. Da luften i skruerne er i stand til at strømme ud bagud gennem et smalt hul, transporteres mediet kontinuerligt og fri fra luft. Dette er en vigtig faktor, hvis mediet skal skæres, forarbejdes eller dispenseres lige efter at have været i trykdysen. KNOLL har placeret et gear mellem drevet og den aktuelle pumpe til synkronisering af skruerne. Det garanterer kontaktfri intermeshing, minimerer slitage og bidrager til pumpens tørre drift. KNOLL-dobbeltskruepumpen fås med skruer af plast eller rustfrit stål; Sidstnævnte anbefales til behandling af chokoladeblokke. Plastskruer - fremstillet af fødevarekompatibel polyamid - er ideelle til brug ved ekstremt lave temperaturer, dvs. til behandling af faste produktblokke ved temperaturer så lave som -18 ° C. I dette tilfælde foregår pumpen med en reducer, der brækker de store blokke i stykker 10 x 10 cm, inden de falder ind i dobbeltskruepumpen.
Godt gennemtænkt pumpesignal
The delivery capacity of the KNOLL double screw pump, which can be up to 10 t/h, is not the only testament to a well-thought-out development. The ease of cleaning of the pump is also an important criterion in the foodstuffs sector in particular. For example, all separation points feature quick-release catches. The drive unit can be removed from the pump housing on a rail system, complete with the screws. The screws and housing are then exposed and can be manually cleaned with a steam blaster or similar. Very little residue remains in the pump after the conveyance operation. This is because the geometry of the pump housing is so precisely measured that the gap is just a few tenths of a millimetre. Accident prevention regulations have been strictly observed in the design. For example, a non-contact safety switch provides for reliable stoppage of the drive when the pressure nozzle is opened (this can be done using a hinge). The KNOLL double-screw pump is designed for the food industry and is therefore fully compliant with FDA requirements. The housing parts and screws are made of high-quality stainless steel or ultra-hard polyamide 6. This plastic is food compatible and resistant to acids, alkalis and oils. Water is also unable to damage it, for the polyamide 6 used does not swell. Compared to stainless steel, the plastic has the advantage of a substantially lower weight.