vacuum shovel dryers
Vacuum drying is characterised by low drying temperatures that are gentle to the product and the possibility of high evaporation rates. Credit: Lödige.

Vacuum shovel dryers are used throughout the pharmaceutical industry for mixing, granulating and drying high-quality pharmaceutical products. The array of specialised applications is extensive.

Lödige shovel dryers are batch vacuum dryers. The mixing elements are frequency-controlled for ideal adaptation to the method. Unique rotating mixing elements, located in a cylindrical drum implemented with a temperature control jacket, form a three-dimensional product movement. The resulting contact frequency of the particles with the heat exchange surface leads to significantly quick drying times.

Silvia Schäfers discusses with GlobalData why Lödige’s vacuum shovel dryer technology is ideal for pharmaceutical applications.

Victoria Smith: What are your company’s latest innovations in Vacuum shovel drying?

Silvia Schäfers: The process engineering possibilities of Lödige vacuum shovel dryers were comprehensively extended in addition to their pure functionality as vacuum dryers. Thus, the systems can be equipped with various options for liquid addition and distribution. They can, therefore, also be used for granulation processes. The possibility of discharge through an integrated sieve mill for material pre-treatment or size calibration of the granulate after drying completes the process engineering possibilities of the machines. The pneumatic feeding and discharge of the vacuum shovel dryers are realised with the process vacuum unit. Also new is the option of a lateral change of the process filters used. This advantage is particularly important when the room height is limited. Lastly, the vacuum shovel dryers have an optimised Hygienic Design: for this purpose, the pipes for heating and cooling the individual machine segments were completely concealed or integrated into the heating jacket.

VS: What really sets Lödige’s vacuum shovel dryers aside from other similar products on the market? What can you offer that no one else can?

SS: Compared to conventional drying processes, the Lödige vacuum shovel dryer is characterised by a multitude of process engineering advantages, starting with vacuum feeding. The product can be sucked into the machine in a space-saving manner and without additional feeding equipment.

The machines are also equipped for different process engineering steps: Vacuum shovel dryers enable the production of mixes by using the proven principle of the horizontal Lödige Ploughshare® Mixers. In addition, the mixing tools support the drying process through the constant exchange between the heating surface and the product. The use of carrier gas is possible in the drying process. Effective cooling is also achieved via the optimum exchange between product and cooling surface with the aid of the mixing elements.

Vacuum shovel dryers can also be used for granulation processes. For this purpose, various options are available for liquid addition with single- or dual-substance nozzles. The discharge with an integrated conical sieve mill enables the final calibration of the granulate size. The pneumatic product discharge can be carried out gravimetrically or with the aid of the process vacuum unit and a downstream separating container. Wash-in-place (WIP) concepts and WIP systems are available for the complete systems. The layout and design of the vacuum dryer, including peripherals, are customised based on the respective product and process requirements.

VS: How does this technology aid in the field of pharmaceuticals?

SS: Vacuum drying is characterised by low drying temperatures that are gentle to the product and the possibility of high evaporation rates, reducing the resulting process times, which means that even temperature-sensitive products such as hormone preparations can be dried gently. In the pharmaceutical sector, high-containment applications can be realised by combining numerous different process steps in one system. As a single-pot unit, vacuum shovel dryers can combine the function of several machines in a single system, eliminating the need to transfer the product. Cleaning and maintenance costs are significantly reduced. Another common process in pharmaceutical production using vacuum shovel dryers is the production of effervescent tablets.

VS: How do you see this product evolving in the future? Do you have plans to adapt upon this product or to extend the range further?

SS: Lödige is working intensively on the development of further possible applications of the vacuum shovel dryer for the pharmaceutical sector. The high flexibility of the system and its diverse process engineering possibilities allow new opportunities. In particular, the number of high containment applications that can be excellently implemented in vacuum shovel dryers is steadily increasing. In addition, application drying interface (API) drying is another forward-looking application.