Custom solution: flow heater for high-precision medical & laboratory equipment
⏱ approx. 6 minutes
CUSTOMER / INDUSTRY
Medical Technology, Laboratory applications
CUSTOMER REQUIREMENTS
The customer requires an instantaneous water heater for precise temperature control of water baths and approached DBK with the following requirements for a heating solution:
The available installation space in the end application requires a rod-shaped design of the heating element.
Power reserves are required to minimize heating time and to allow for dynamic application.
Since the customer's product will be sold worldwide, the heating element must be able to operate smoothly at 115 VAC as well as at 230 VAC.
High power ratings in a small installation space require a protection in case of malfunctions. Therefore, a temperature sensor and an overtemperature protection must be installed in the heating element, particularly close to the active heating zone.
Further, highly corrosive liquids may come into contact with the heating element and the housing of the heater during subsequent use. To avoid damage to the components, the materials used must be adapted to these ambient conditions.
TECHNICAL HEATING SOLUTION
According to the customer's technical specification, a solution based on traditional resistance wire heating technology was chosen:
Power output per surface area
As the design space already indicates, the heater must be a cartridge heater that can achieve a high power output. A high-performance cartridge delivers a very high power density of more than 16 W/cm², which means that the total power results in 1200W. The requirement for dynamics and heating time are fulfilled.Operating Voltage
To meet the requirement of 115VAC/230VAC operating voltage, the heating element is divided into two heating zones, which are designed for an operating voltage of 115 VAC. Thus, the operation in both voltage ranges can be realized via the wiring in the customer's device.
Safety fuse
The heating element can be controlled very dynamically via the type J temperature sensor integrated directly into the heating cartridge, in the immediate vicinity of the heating zone. In case of failure of all customer safety devices, the integrated overtemperature fuse disconnects the main supply line of the heating element.
Corrosion resistance
The housing as well as the heating cartridge itself are made of high-quality stainless steel 1:4404. All connections are joined with nickel-base solder in a high-temperature vacuum brazing process or by laser welding. For additional corrosion resistance, the flow heater housing is subjected to a final pickling/passivation process. The gaskets used for the flow heater were also selected for the corrosion resistance requirement.