Compact and extremely tough: Special hygienic rotary lobe pump delivers edible oil flexibly and with care

In everyday practice in the foodstuff industry high demands on hygienic processing are required for the primarily sensitive product, simultaneously, there is the high pressure of competition and efficiency.

The TORNADO® T2 rotary lobe pump, installed on a moving device – this is an option of a design variant that NETZSCH offers for each customer application.

Modern production and conveying systems are especially developed for this requirement profile. An example of this is the new TORNADO® T.Sano rotary lobe pump from NETZSCH Pumpen & Systeme GmbH. The pump chamber is made completely from stainless steel. Simultaneously, the new construction provides for less pulsation and wear. For a large producer of edible oil, a TORNADO® T.Sano rotary lobe pump, together with measurement cell and control unit, has been installed on a small trolley to enable direct and flexible filling of different types of containers.

According to the manufacturer, barrels of 50 to 200 litres, IBC barrels and complete tankers of 30 cubic metres volume can be filled within a maximum of one hour with different types of edible oils. Due to the different types of containers for transportation, stationary delivery equipment cannot be considered, instead, up to present, a geared pump installed on a small trolley has been used. However, this was not at all satisfactory, because the gears of the pump were overloaded.

In order to reduce the high wear and, thus, the resulting frequent maintenance resulting, the system was changed last year to a TORNADO® T.Sano rotary lobe pump. This operates with two dual-bladed lobes that are exactly aligned to one another, as well as the geometry of the pump chamber. Thus, contact between the components and the resulting material abrasion is avoided. Furthermore, the form of the rotary lobe rotor ensures high stability during operation, due to the large ball passage, the system is insensitive to foreign substances and provides quick replacement in the event of maintenance.

Delivery technology especially for delicate foodstuffs: The complete metal rotary lobe pump T.Sano is designed for high demands on efficiency and conservation of products.

However, for the design of the pump, the particular characteristics of the edible oil must also be taken into consideration. In another plant, the centrifugal pumps used would have shattered the oil into droplets. Pulsation can cause a problem for rotary lobe pumps. Thus, in order to reduce this, multiple bladed lobes are usually used for sensitive media. In contrast, NETZSCH relies on the special shape of the delivery chamber of the TORNDAO® T2 series. Small pockets, machined into the inner wall, make sure that the material can smoothly flow into the delivery chamber. The pulsation of the two-bladed lobe also remains at the level of four-bladed lobe, so that the edible oil can be filled without changing the consistency.

Control, measurement and accurate filling in the narrowest of space

In order to exactly dose the product appropriate for the size of container, the pump has been combined with a measurement cell and control cabinet. Different filling programs can be called up and started using a display with Touch function. The control parameter is always the required fill weight that results from the density of the oil and volume delivered. The latter is determined using a turbine flow controller, conforming to the hygienic specifications, installed in the pipeline. As the quantity delivered by the pump can be regulated using a frequency inverter, the result is an accuracy in dosing of approximately one percent of the volume delivered.

So that the pump system, together with all the accessories, can be easily used and moved between the filling positions, a compact construction and low weight were important factors. Due to its innovative drive technology, the T.Sano has a specific advantage: Instead of the usual, but very complex and heavy timing gear, a belt drive is used for this series. This transmits the power from the drive to the shafts and, through the cogs, simultaneously ensures synchronization of the lobe revolutions. With this system, the motor can be directly flanged above the pump by using a console, which results in an extremely short installation length. Together with the measurement apparatus and control, the system can be installed on a moving device of only 1.3 by 0.6 metres and is just over one metre in height. As the drive comprises of fewer components than a conventional gearbox, it is significantly lighter. Thus, the flexibility required by the manufacturer is assured in all application situations. In addition, the belt drive simplifies any maintenance tasks and requires no lubrication. Due to the continuous hard-soft contact between drive, belt and shafts, a high level of smooth running is attained, which protects the components in general.

Complete metal design for high safety and easy cleaning

The complete pump chamber is designed free of dead space, in order to make cleaning easier.

In order to conform to the requirements of food safety and FDA regarding materials in the food processing sector, all metallic components of the rotary lobe pump that come into contact with the delivery medium are designed in stainless steel and the elastomer seals in accordance with the FDA. Special mechanical seals, in cartridge construction, ensure that the sealing is reliable. The lobe itself is attached with taper lock ringsets on the outside of the housing. On the one hand, this simplifies installation and removal and, on the other hand, contributes in maintaining the delivery area free from dead space. For complete cleaning or inspection, the front cover can be removed, whereby, the complete pump chamber is accessible.

The T.Sano is available in different sizes for delivery quantities of 8 to 140 m³/h. The smallest model is suitable for the flexible filling of edible oil described, because here, only up to 27 m³/h must be delivered at a back-pressure of up to 4 bar. The speed is variably set at approximately 150 to 440 rpm. The T.Sano fulfils the delivery function to the complete satisfaction of the oil producer.