Dialysis machines

Medical engineering

Lasting and precise compontents for long-lives dialysis machines

Manufacturers of dialysis machines must be able to fully rely on the components of their devices. The machines have to operate reliably and persistently to offer dialysis patients the necessary treatment. For this purpose, the product portfolio of EBE includes sensor solutions and HMI components that excel by precisely these qualities.

Level monitoring off all media by means of touchless sensor systems

EBE level sensors reliably detect liquid columns in containers of non-conductive materials. They do not only look through container walls but also through adhesions of blood, dialysate and even heparine or bicarbonate. The evaluation algorithms can be designed for a great variety of ambient and usage conditions. For this purpose, the technology uses a multi-channel capacitive measuring process. This excites the measuring electrodes in a defined spectral range. Due to adhesive films on the container walls, conventional capacitive sensors are likely to show incorrect measurements. For the EBE technology, it doesn’t matter how viscous, adhesive or conductive a medium is. The parasitic effects resulting from the coatings are compensated by the EBE algorithms. The filling level is measured reliably at any time.

Combination sensors monitor the placement of containers and tanks

The level measurement at the extracorporal blood circulation is required at different places. It is necessary to constantly monitor the filling level of blood or blood supply at the drip chambers of the hose system. At the machine itself, the filling level of the canisters with dialysis water, the cartridge with bicarbonate and more have to be monitored. Capacitive level sensors that are also equipped with an inductive sensor are particularly suitable here to prevent measuring errors by wrongly placed containers. If varying gap sizes between the tank and the frame exceed 2 mm, level measurement often poses a problem for common capacitive sensors. By the additionally used proximity sensor the actual distance between the sensor surface and the tank surface is measured. A small piece of aluminium as counterpart of the inductive sensor is absolutely sufficient. Based on the individual air gap, the parameters for the capacitive sensor are thus tracked in real time. The coil structure required for the proximity sensor is integrated on the PCB of the capacitive sensor. The existing µ-controller simply assumes the electronic evaluation and calculation.

Easy-to-sterilize control panels

Sterile surfaces are particularly important in the medical field. HMI components from EBE sensors + motion offer a variety of solutions. Classic switches, buttons and rotary encoders can be realized moisture-proof. Sensor-based HMI components are particularly suitable, though. They are utilized beneath the closed surface. Thus, they are not affected by continuous cleaning and disinfection. Nevertheless, even in case of contamination or film coatings the capacitive buttons always work reliably. The sensor buttons can be assigned multiple functions which also saves space on the control panel. Sensor-based rotary encoders combine the advantages of both worlds. They offer the feel of a classic rotary encoder, including haptic feedback. Still, they are utilized beneath a completely closed surface. For this purpose, the elevation for the rotary encoder has to be considered before casting the surface. Thus, the system is completely tight with respect to moisture, dust and other disruptive factors, offering ideal preconditions for a hygienic user interface.