NETZSCH Pumps & Systems has developed special barrel emptying systems that function as sealed systems, due to a tailored secondary plate, and are sufficiently powerful on the suction side to leave residues of just 1%-2%. In the current reworked version, the entire design has been slimmed down for simpler cleaning and mobility.
Users of the barrel emptying system in the food industry include a manufacturer of fruit juice bottling systems with processing lines where juice concentrate is delivered in barrels. To convey the contents for further processing, the barrels used to be placed in a tilting unit to be emptied into a hopper via a pump. Inserting and pivoting the full barrels, however, was very time-consuming and barrels could not be emptied completely, which necessitated extensive cleaning. Hygiene was even more problematic, as the juice is decanted a number of times in the process and is therefore susceptible to foreign matter.
Self-priming emptying system leaves almost no residues
To make this processing step simpler and safer, the company switched its filling lines from the tilting unit to the NBE 200 barrel emptying system from NETZSCH. The system consists of a progressing cavity pump hung vertically in a frame and fitted with a follow plate at the pump inlet. The size of the plate is tailored to the barrel to be emptied and is fitted with an elastomer sleeve so that it closes airtight to the barrel. When the pump is switched on, a vacuum forms and the barrel emptying system begins to automatically suck towards the floor. The light pressure exerted by the plate on the medium prevents air pockets and ensures continuous conveying. Almost the entire volume can then be processed with only around 1% left in the barrel.
The pump is a NEMO® Hygienic Pump that complies with EDEHG and QHD guidelines as well as the American 3-A Sanitary Standard and Russian GOST-R. At the heart of the system is a combination of helix rotor and enclosing reverse-helix stator jackets. Conveying chambers of the same size form with each rotation to convey the medium without fluctuations in pressure, pulsation or strong shearing forces thanks to the precise geometric coordination of the two components. The entire pump chamber is designed to be hydrodynamic and free of dead space to avoid deposits. Depending on the conveyed fluid, either constantly rinsed open joints or a smooth flexible rod are used to transfer the torque.
More efficient design principles for faster cleaning and greater flexibility
All surfaces in contact with the product are also polished to minimise the risk of deposits. Stainless-steel grade 1.4571, for example, is the main material used and the levelling collar is made from a special elastomer approved by the FDA. The installed materials also make it possible to follow the CIP cleaning procedure to clean the pump. Almost no individual parts have to be cleaned, as only one seal comes into contact with the material in this process.
In the latest NBE model series, this feature has been improved even further by reducing the number of individual parts and developing a slimmer and more efficient design. The system can now be cleaned significantly quicker. The new design has the additional advantage of meeting all volume requirements in just three different sizes. Even very specific application requirements can therefore be met with minimal complexity. Responses to the changes have been consistently positive, with 20 of the new-style systems sold in 2013.
Control variants from simple switching to comprehensive control
A number of control options are available, from a simple start-stop switch to a touch panel that clearly displays all system components and process parameters. The quantity conveyed can be adjusted infinitely thanks to the special way that the progressing cavity pump functions, which can be reversed if necessary. In addition, sensors on the pneumatic cylinders detect when the barrel is empty and interrupt the emptying procedure to prevent the system running dry. The emptying system can also easily be integrated into an automated production line. The pump manufacturer coordinates the necessary interfaces with the production line supplier.
The NBE barrel emptying system from NETZSCH is suitable for barrels from 0.5l – 200l at flows rates between 6ml per minute and 10m³/h. In special cases, custom solutions can also be developed for up to 1,000l. A system with a flow of 11.6m³/h at 188rpm and maximum 12bar pressure was installed for the fruit juice bottling systems manufacturer. The bottle filler can empty one barrel per minute leaving almost no residue and thanks to the optional integrated roller conveyor the barrels are also exchanged quickly.