Today, chocolates, chocolate bars and a variety of pralines are manufactured industrially. Nevertheless, the process of making chocolate demands considerable know-how and can only be carried out efficiently using modern systems. Innovative manufacturers – such as Nestlé AG – use, for example, the double screw pump from KNOLL MB, to plasticise large blocks of chocolate.
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.
Dobbelt skrue pumper er i stand til at blødgøre faste blokke
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.
At the heart of a double screw pump such as this, is a full screw and an open screw which intermesh. This produces a forced-feed effect, so that everything which enters the pump is reliably pushed out. Formation of rolls is prevented by the interlocking of the screws. Since the air in the screws is able to flow out backwards through a narrow gap, the medium is conveyed continuously and free from air. This is an important factor if the medium is to be cut, processed or dispensed straight after leaving the pressure nozzle. KNOLL has positioned a gear between the drive and the actual pump for synchronising the screws. That guarantees contact-free intermeshing, minimising wear and contributing to the dry-run safe operation of the pump. The KNOLL double screw pump is available with plastic or stainless steel screws; the latter are recommended for processing blocks of chocolate. Plastic screws – made of food-compatible polyamide – are ideal for use at extremely low temperatures, i.e. for processing solid blocks of product at temperatures as low as -18°C. In this case, the pump is preceded by a reducer which breaks the large blocks into pieces 10 x 10 cm in size before they drop into the double screw pump.
Godt gennemtænkt pumpesignal
Leveringskapaciteten af KNOLL dobbelt skruepumpe, som kan være op til 10 t / h, er ikke det eneste testamente til en velovervejet udvikling. Rengøringen af pumpen er også et vigtigt kriterium i fødevaresektoren. For eksempel indeholder alle separationspunkter hurtige frigivelser. Drivaggregatet kan fjernes fra pumpehuset på et skinnesystem, komplet med skruerne. Skruerne og huset er så eksponeret og kan rengøres manuelt med en dampblæser eller lignende. Meget lille rest forbliver i pumpen efter transportoperationen. Dette skyldes, at pumpehusets geometri er så præcist målt, at afstanden kun er få tiendedele millimeter. Ulykkesforebyggelsesbestemmelser er blevet overholdt strengt i designet. For eksempel giver en kontaktkontakt sikkerhedsafbryder mulighed for pålidelig stop af drevet, når trykdysen åbnes (dette kan gøres ved hjælp af et hængsel). KNOLL-dobbeltskruepumpen er designet til fødevareindustrien og er derfor fuldt ud i overensstemmelse med FDA-kravene. Husdelene og skruerne er lavet af rustfrit stål eller ultrahård polyamid 6 af høj kvalitet. Denne plastik er fødevarekompatibel og modstandsdygtig over for syrer, alkalier og olier. Vand kan heller ikke beskadige det, fordi det anvendte polyamid 6 ikke svulmer. Sammenlignet med rustfrit stål har plasten fordelene ved en væsentlig lavere vægt.