Revolutionary radiation heating

Why are today's best and most expensive bioreactors always equipped with jacketed vessels and thermal circulating bathes?

Such equipment is very expensive, voluminous, unpractical and has many other serious problems. Just to mention a few: a very high heat capacity, a low heat transfer during sterilization either with water filled in the jacket or without any water and the consequential longer sterilization times resulting in increased degradation of medium; long cooling-down times; the need for cooling water supplies with the corresponding necessity of additional tubing connections which in turn increase the complexity around the culture vessel; the necessity of expensive circulating pumps etc.

The main reason for using thermal circulating baths lies in the elimination of hot spots on the vessel walls.

All other cheaper heating systems do not eliminate them well or only partially. This is the case of heating blankets, heating clamps etc. The worst of all are heating fingers or rods which even create very dangerous hot spots directly in medium!! They are put into bioreactors by unscrupulous producers only because of their minimal costs. Their inexperienced clients who buy such a "bioreactor" will have to pay for their experience by time and money loss until they decide to throw it away and buy a better bioreactor.

We cannot understand that nobody has thought about using radiation heating before LAMBDA! It solves the problem perfectly and brings so many advantages:

• generation of infrared radiation is so easy and cheap! Just let current flow through a metal wire.
• heat rays are similar to visible light and can be easily reflected by metallic mirrors (gold being the most efficient). A parabolic reflector spreads the radiation evenly to the whole bottom surface. The vessel bottom does not need be perfectly flat.
• heat of certain wavelength is absorbed by glass other wavelengths pass through it and are absorbed directly by the water molecules in the medium in a similar way as sun heats water. Both lead to an extremely soft heating. No hot spots can ever form if the IR radiation is directed on the bottom of the vessel.
• given that no losses occur, the power (wattage) of the IR heater can be much smaller. (Heating blankets and jacketed vessels have higher heat losses than the amount of heat transmitted into medium. They also prevent natural cooling and therefore higher cooling power is necessary.)
• since only a short piece of wire is required and metals have very low heat capacity, the IR heating is rapidly switched on and off. It heats up and cools down extremely fast. This leads to a much more precise temperature control in the vessel. Think just about the liters of water (having an enormous heat capacity) in the jacket and the bath. This water volume has to be warmed many degrees of centigrade above the desired medium temperature to get any significant heat transfer. When the temperature is attained, this volume of water must be cooled down to prevent temperature overshooting. It is obvious that the temperature control is much more difficult than with radiation heating.
• even a very slight increase in temperature leads to natural thermal convection. Since the radiation is directed to the bottom of the vessel, the convection equalizes the temperature in the medium even without any agitation at all. For example, the variation of the temperature set to 30°C gives deviations of only +/- 0.1°C in a one liter vessel!