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SOLUTIONS & APPLICATIONS




                            nerations of screw vacuum pumps, the pitch of the   •   Sensitive to particles entering the system
                            screws is the same across the entire length. This   •   Cannot be used with process gases that tend
                            leads to compression of the process gas in the last   to be reactive at high temperatures
                            half rotation of the screw, which generates exces-
                            sive thermal load there. Thus, adjusting to the ideal
                            operating temperature with water cooling is more  Once-through oil-lubricated
                            difficult. Generally, dry screw vacuum pumps ope-  rotary vane vacuum pumps
                            rate at higher temperatures than liquid ring vacuum
                            pumps. Condensation of process gas elements is   Oil-lubricated  rotary  vane  vacuum  pumps  have
                            thus  largely  eliminated.  This  enables  the  process   been successfully used in many fields for decades.
                            gas to be conveyed through the vacuum pump wi-  Today, they are amongst the most widely used
                            thout contamination or causing a reaction with an   mechanical vacuum pumps in the industry. Busch
                            operating fluid. Cast iron is the standard material   already  developed  the Huckepack,  a  two-stage
                            used for work pieces for all parts that come into   once-through oil-lubricated rotary vane vacuum
                            contact with the pumped medium. It is either un-  pump  in  the  1960s,  which  was  specially  desig-
                            treated or treated with a special coating to make   ned for chemical and pharmaceutical processing
                            it resistant to nearly all chemicals. After the end of   technology. Busch has constantly further develo-
                            the process, we recommend flushing the vacuum   ped this vacuum pump, which continues to enjoy
                            pump with a suitable cleaning fluid and to purge it   great acceptance in processing technology today
                            with nitrogen to avoid corrosion and deposit for-  thanks to its robustness.
                            ming during stand-still.
                                                                      Huckepack rotary vane vacuum pumps (Fig. 5)
                            With different sealing systems and various coa-  have three significant distinguishing features when
                            tings, screw vacuum pumps from Busch can be   compared  to  other  vacuum  pumps  that  operate
                            configured to be compatible with any chemical.  according to the rotary vane principle:
                                                                      1.  Two compression stages are stacked and
                            Advantages of dry screw vacuum pumps:        connected to each other which facilitates
                            •   Dry compression, no contamination or reac-  initial compression of the process gas in the
                                tion possible between process gas and ope-  first stage and secondary compression in the
                                rating fluid                             subsequent second stage. This makes it pos-
                            •   High vacuum level                        sible to achieve a lower ultimate pressure.
                            •   Energy efficient                      2.  These vacuum pumps feature an oil-lubrica-
                            •   Can be designed for nearly all process gases   tion  which  means  that  a defined  amount  of
                                thanks to material selection and temperature   operating fluid, oil or other media-compatible
                                regulation                               fluid is injected into the compression chamber.
                                                                         In contrast, other rotary vane vacuum pumps
                            Disadvantages of dry screw vacuum pumps:     use oil circulating lubrication.


                            Tecnologia del vuoto per l’industria

                            chimica e farmaceutica


                            La scelta della tecnologia del vuoto più adeguata per le applicazioni di processo in campo
                            chimico e farmaceutico è spesso difficile. Da un lato, un sistema per vuoto deve fornire
                            la capacità di aspirazione richiesta alla pressione di esercizio e garantire così il tempo di
                            evacuazione necessario. Dall’altro, deve essere resistente ai gas di processo e soddisfare
                            tutti i requisiti relativi ai sistemi di sanificazione in loco (CIP, clean in place) e recupero di gas.
                            L’affidabilità e l’efficienza economica ricoprono inoltre un ruolo decisivo nel decidere quale tipo di
                            tecnologia del vuoto usare.
                            Tre le tecnologie del vuoto più usate nei processi chimici e farmaceutici:
                            •   Pompe per vuoto ad anello liquido;
                            •   Pompe per vuoto a vite a secco;
                            •   Pompe per vuoto rotative a palette lubrificate a olio.

                            Tutte le tecnologie di generazione del vuoto presentano vantaggi e svantaggi. Non esiste una
                            soluzione ideale per tutte le applicazioni. Per questo è importante consultare un esperto del vuoto
                            e considerare tutti i parametri coinvolti: a partire dalle condizioni di processo, i gas di processo e
                            l’integrazione nel controllo del processo fino alla considerazione degli aspetti relativi all’efficienza
                            economica, alla sicurezza e all’affidabilità della futura generazione del vuoto. Il risultato di queste
                            considerazioni sarà nella maggior parte dei casi un sistema per vuoto individuale a misura dei
                            requisiti.



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