Heating and cooling performance of the 200 L LevMixer™ and magnetic mixer tank gen V
In this study we evaluated and compared the heating and cooling performance of the 200 L LevMixer™ and magnetic mixer tank gen V with an older generation tank. We also evaluated the performance of the extension to our range–the 1600 L LevMixer™ and magnetic mixer tank gen V.
Our gen V tanks have been designed with a bottom jacket in addition to side jackets and this study has shown:
- A reduction in cooling time of 45 minutes (from 228 to 183 min)
- A reduction in heating time of 7 minutes (from 93 to 86 min)
- The ability to cool to 4°C in 86 min with a minimum mixing volume (MMV)
Introduction
Heating and cooling performance of a mixer is an important process parameter to consider, especially at larger volumes where such steps typically take a long time. Glucose solution preparation is one example which requires heating to quicky dissolve the powder, followed by cooling down to a set temperature before use. Other examples of process steps requiring heating or cooling to specific temperatures, ideally in the shortest possible time are:
- Prior to filling a bioreactor
- Maintaining a certain temperature for sensitive products
- Maintaining product solutions at low temperature for storage
The prior LevMixer™ and magnetic mixer tank designs are mounted with side jackets whereas the gen V tank is also equipped with a bottom jacket, improving the heat exchange surface with a larger area facilitating better performance at low working volumes. In this study, the heating and cooling performance of the tanks were determined at nominal volume (100%) and MMVs, where the impeller is fully covered with liquid.
For each tank size and volume, a heating and cooling cycle was carried out between temperatures of 40°C and 4°C. Temperature was measured and recorded at the top and bottom of the mixing tank to collect data from these two different and opposite locations.
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Fig 1. 200 L LevMixer™ system gen V (above) and the 1600 L LevMixer™ and magnetic mixer tank gen V (below).
The results gained in this study are for guidance only and should not be considered as a full validation. They highlight the benefits of the new design with the bottom jacket and the gain in time for both the heating and cooling processes with the temperature control unit (TCU) models used in this study.
Materials and methods
The experiments were carried out on two tanks and volumes:
- Nominal volume (= 100% filling volume): 200 L and 1600 L
- The MMV: 30 L for the 200 L tank, and 122.9 L for the 1600 L tank
Fig 2. Schematic drawing of the minimum operating volumes, including the MMV tested.
For each test the hardware and single-use systems were installed according to the Instructions For Use (IFU). Temperature sensors were then installed to their pre-defined positions (Fig 3) to allow measurement of temperature at both locations.
Both sensors were connected to the Pico Log instrument to allow data recording.
For each volume, both the heating (4°C to 40°C) and cooling (40°C to 4°C) cycles were performed using the LAUDA Variocool VC 10000 with the 200 L tanks and the LAUDA Ultracool UC 3005 HW Circulation thermostat with the 1600 L tank. Manual setpoints were used for temperature controls as the focus was to generate comparative data and highlight the benefits of the bottom jacket in the heating and cooling process times.
The TCU setpoint during heating and cooling were 60°C and -4.5°C respectively.
Temperature sensor locations (Fig 3)
- Sensor 1 (bottom): An RS PRO K Needle temperature probe was inserted into the sampling line of the mixer (in direct contact with liquid)
- Sensor 2 (top): A second RS PRO K Needle temperature probe was positioned on top, front and left corner (just immersed in the surface of the liquid at around 3 cm depth and 5 cm from the tank walls)
Mixing speed
For the 200 L LevMixer™ and magnetic mixer tanks the mixing speed was set to 60 rpm at nominal volume (200 L) and 49 rpm at the MMV.
For the 1600 L LevMixer™ and magnetic mixer tank gen V the mixing speed was set to 180 rpm at nominal volume (1600 L) and 43 rpm at the MMV. These are the maximum speed without a vortex.
Fig 3. Temperature sensors positioning (indicative).
Table 1. Materials and equipment
| Equipment | Product code |
| 1600 L LevMixer™ and magnetic mixer tank gen V | LM1600BCTE-B4N |
| 200 L LevMixer™ and magnetic mixer tank | LM200JCN-B4N |
| 200 L LevMixer™ and magnetic mixer tank gen V | LM200BCTE-B4N |
| LevMixer™ drive unit | LMG403 |
| LevMixer™ drive unit gen V | LMG501 |
| LAUDA Ultracool UC 3005 HW | XMTCU-UC3005 |
| TCU LAUDA Variocool | TCU-LA-V10A-UL |
| 1600 L single-use biocontainer bag | 6403-1857R |
| 200 L single-use biocontainer bag | 6403-2191R |
Table 2. Total surface area increase (%) utilizing LevMixer™ and magnetic mixer tanks gen V (with the bottom jacket)
| Surface area side walls (m2) | Surface area bottom (m2) | Total surface area with side and bottom jackets - gen V tanks (m2) | Increase in surface area with the bottom jacket of the - gen V tanks (%) | |
| LM50BCTE | 0.41 | 0.058 | 0.47 | 14.6 |
| LM100BCTE | 0.53 | 0.115 | 0.64 | 21.5 |
| LM200BCTE | 0.83 | 0.202 | 1.01 | 24.1 |
| LM400BCTE | 1.17 | 0.3 | 1.47 | 25.6 |
| LM650BCTE | 1.84 | 0.535 | 2.38 | 29.1 |
| LM1000BCTE | 2.35 | 0.75 | 3.1 | 32.2 |
| TLM1600BCTE | 3.49 | 0.98 | 4.47 | Not applicable |
Results
Fig 4. Older generation 200 L LevMixer™ and magnetic mixer tank: Cooling from 40°C to 4°C; MMV (30 L).
Fig 5. 200 L LevMixer™ and magnetic mixer tank gen V: Cooling from 40°C to 4°C; MMV (30 L).
Fig 6. Older generation 200 L LevMixer™ and magnetic mixer tank: heating from 4°C to 40°C; MMV (30 L).
Fig 7. 200 L LevMixer™ and magnetic mixer tank gen V: heating from 4°C to 40°C; MMV (30 L).
Fig 8. Older generation 200 L LevMixer™ and magnetic mixer tank: Cooling from 40°C to 4°C, nominal volume of 200 L. Only top sensor location available with the single-use system used.
Fig 9. 200 L LevMixer™ and magnetic mixer tank gen V: cooling from 40°C to 4°C; nominal volume of 200 L.
Fig 10. Older generation 200 L LevMixer™ and magnetic mixer tank: heating from 4°C to 40°C; nominal volume of 200 L. Only top sensor location available with the single-use system used.
Fig 11. 200 L LevMixer™ and magnetic mixer tank gen V: heating from 4°C to 40°C; nominal volume of 200 L.
Fig 12. 1600 L LevMixer™ and magnetic mixer tank gen V: cooling from 40°C to 4°C; MMV (122.9 L).
Fig 13. 1600 L LevMixer™ and magnetic mixer tank gen V: heating from 4°C to 40°C; MMV (122.9 L).
Fig 14. 1600 L LevMixer™ and magnetic mixer tank gen V: cooling from 40°C to 4°C; nominal volume of 1600 L.
Fig 15. 1600 L LevMixer™ and magnetic mixer tank: heating from 4°C to 40°C, nominal volume of 1600 L.
Table 3. Heating and cooling times and comparison of the older generation and gen V tanks
| Nominal volume (200 L) | ||||||||
| Test | Temperature (initial to setpoint °C) | Older generation 200 L tank (min) | Gen V 200 L tank (time min) | Improvement older generation vs Gen V (%) | ||||
| Cooling | 40 to 4 | 228 | 183 | 24.1 | ||||
| Heating | 4 to 40 | 93 | 86 | 8.1 | ||||
| MMV (30 L) | ||||||||
| Cooling | 40 to 4 | >400* | 92 | Not applicable* | ||||
| Heating | 4 to 40 | 114 | 43 | 265 | ||||
*Setpoint of 4°C could not be reached with the older generation LevMixer™ and magnetic mixer tank
Table 4. Heating and cooling times in the 1600 L LevMixer™ and magnetic mixer tank gen V
| Nominal volume (1600 L) | ||||||||
| Test | Temperature (°C) | 1600 L tank (time min) |
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| Cooling | 40 to 4 | 308 | ||||||
| Heating | 4 to 40 | 141 | ||||||
| MMV (122.9 L) | ||||||||
| Cooling | 40 to 4 | 163 | ||||||
| Heating | 4 to 40 | 51 | ||||||
Conclusion
The experimental results confirm that the LevMixer™ and magnetic mixer tank gen V heat and cool faster because of the additional bottom jacket which is integral to this design.
The results obtained on the 200 L tanks at nominal volume showed that the presence of the bottom jacket significantly contributed to the reduction in cooling time from 228 min for the older generation tank to 183 for the gen V tank, saving 45 mins. Similarly, the heating time was considerably improved, taking 86 min with the gen V tank versus 93 min with the older generation tank.
At the MMV, the improvements were even more significant. The older generation tank was unable to reach the cooling target temperature of 4°C within 6 hours and 40 minutes, remaining static at 6°C. In contrast, the new gen V tank successfully achieved the target temperature in just 92 minutes. Additionally, a better performance was also observed for the gen V tank, with the heating process taking only 43 minutes, while the older generation tank required 114 minutes.
These results show the benefits of the bottom jackets at both filling levels and more significantly at the MMV where the setpoint of 4°C could not be reached with the older generation tank.
CY51253-02Jul25-AN