Abstract: A fluid level sensor to determine the level of fluid into a container used in negative pressure wound therapy. The sensor includes an array of conductive plates to produce electric field lines through the container and fluid within, the plates serving as the plates of a capacitor. The plates (1-4), are located close to the wall of the container, and are connected to a circuit board, electronics and software to determine the fluid level in the container based on the relative changes of capacitance between the plates. The capacitance is converted into a voltage signal representative of the change. The algorithms are designed to check the fluid level over predefined time periods to indicate the fluid level at more than one point and also track the fluid level. The fluid sensor can be used in the vertical, horizontal or other position of the container as desired.

Abstract: A fluid level sensor to determine the level of fluid into a container used in negative pressure wound therapy. The sensor includes an array of conductive plates to produce electric field lines through the container and fluid within, the plates serving as the plates of a capacitor. The plates (1-4), are located close to the wall of the container, and are connected to a circuit board, electronics and software to determine the fluid level in the container based on the relative changes of capacitance between the plates. The capacitance is converted into a voltage signal representative of the change. The algorithms are designed to check the fluid level over predefined time periods to indicate the fluid level at more than one point and also track the fluid level. The fluid sensor can be used in the vertical, horizontal or other position of the container as desired.

Abstract: A fluid flow control system for an electromagnetic pump having an electromagnetic drive (11) and a compressor (6). The control system established a required current in the compressor coils (10) to control the position and movement of the actuator (11), the actuator deflecting a diaphragm within the pump to provide the required flow. The control system includes a command signal generator (1) to create a signal representing the required flow. The signal is applied to a command processor (2) with any feedback signals (13) for example, coil current and/or actuator displacement. The command processor (2) calculates the appropriate drive signal defined by mark-space ratio, repetition rate, and amplitude. The drive signal controls the voltage supplied to the compressor coils (11) resulting in a required coil current to provide the desired flow. A dc power supply is used to avoid problems regarding main power supply and frequency.