For example, these fluids are heated in Pharma-type flange heaters:
I. Ultra-pure water
- Aqua purificata (AP) and/or cleaned or purified water (PW)
- Water for injection purposes (WFI)
- Ultra-clean water as feed water for the generation of ultra-pure steam
- Sterilized air
III. Other fluids
- Hydrogen peroxide
The fluid to be heated and the application temperature mainly define the materials which can be used for the unheated and/or heated surfaces. Otherwise, corrosion may quickly result in a failure of the electrical flange heater, for example.
Materials of the wetted, heated and unheated components
- Corrosion-resistant stainless steel
- Titanium, Hastelloy, special materials
Special designs of the wetted components
- Surface roughness Ra < 0.8 µm, lower surface roughness as an option (Ra < 0.6µm, Ra < 0.4 µm)
- Electropolished design
- Limited delta ferrite content in the basic material and weld
The design of the individual heating elements is a function of the application. There are faster or slower heating elements, mechanically robust or more filigree designs. Also, a distinction is made between compacted heating elements and heating elements where the internal heating insert can be replaced without the necessity of draining the fluid.
I. Heating elements
- Tubular heaters, diameter 8.5 or 16 mm
- Cartridge-type heaters, diameter 16, 18 or 25 mm
- Exchangeable heating elements, including a protective tube, diameter 25, 42 or 65 mm
Electrical flange heaters can both be equipped with a built-in control system (for low power) or an external switchgear cabinet or for load switching by customer-provided switchgear and control gear. The electrical heating power can be divided into one or several heating stages. This division can individually be adjusted to match the control equipment.
- Electronic ON-OFF control or PID control.
(-> ON-OFF control switches off the heater if the temperature is exceeded, and switches it on again when the temperature falls below its lowest value. Thus, the temperature will always oscillate around the setpoint. The algorithm of the PID controller will optimally compensate the control fluctuations.)
- Load switching by contactors or wear-free semiconductors (thyristors).
(-> contactors are wearing parts and must be replaced after approx. 100,000 make/break operations; thyristors switch quickly and without any wear but generate more heat losses than contactors.)
- Electromechanical control.
Thermostats installed in the electrical flow-type heater are price-efficient controllers whose accuracy is sufficient for many applications.
- Thermal protectors and limiters as capillary thermostats (as a safety design as well).
- Temperature sensors for the fluid and heating rod temperature.
Overheating protection for the heater or electrical terminal compartment.
The switching devices as required for the operation of the electrical flange heaters can optimally be matched to the process and the heating element; they can be ordered from heatsystems.
I. Switching devices
- Flow-monitoring device
- Low-water level protection
- Min. and max. pressure limiter
- Thermometer for indicating the temperature on site
Normally, the cooling section of the electrical flange heaters (i.e. the section between the flange plate and the electrical terminal box) must normally not be insulated. If this is required for technical reasons, e.g. at fluid temperatures below the freezing point, we are prepared to design a customized model.
The electrical flange heaters - as the name implies - are flanged to the container or the flow tube. A number of options is available for this flange connection:
I. Flange connections
- Standard flanges (DIN, ASME, SAE etc.)
- Clamp flanges (DIN32676)
- Sterile flanges (DIN 11864)
- Dairy-type pipe connections
Available design models for electrical equipment and controlling of the electrical flange heaters are:
I. Design models
- Indoor or outdoor installation
- Hazardous area (zone 1 or 2, 21 or 22)
- Non-harzardous area
- Type of protection IP54 or better
- Switchgear cabinet for wall or floor mounting
- Steel sheet connection housing, powder-coated or stainless steel
- Electronic or electromechanical control
- Communication with higher-level control system by floating contacts, standardized signal or bus