Flow detector

A flow detector for releasable coupling with a flow channel in a channel coupling area and detecting a flow of liquid drug in the flow channel, the flow detector including:

• an upstream thermoelectric element and a downstream thermoelectric element, wherein the upstream thermoelectric element and the downstream thermoelectric element are arranged spaced apart from each other, and wherein the upstream thermoelectric element is arranged to couple to the flow channel in the channel coupling area at an upstream position and the downstream thermoelectric element is arranged to releasably couple to the flow channel in the channel coupling area at a downstream position, such that the downstream thermoelectric element operates as a downstream temperature sensor and senses a downstream temperature at the downstream position;
• wherein the upstream thermoelectric element is configured to operate as a heating element, thereby heating liquid inside the flow channel at the upstream position, and operate as an upstream temperature sensor and sense an upstream temperature at the upstream position;
• wherein the upstream thermoelectric element is arranged on an upstream flexible printed circuit board element;
• wherein the downstream thermoelectric element is mounted on a downstream flexible printed circuit board element;
• and
• wherein the upstream flexible printed circuit board element and the downstream flexible printed circuit board element form fingers that are able to flex independently from one another.

A method for releasably coupling a flow detector with a flow channel for detecting a flow of liquid drug in the flow channel, the method including:

• releasably coupling an upstream thermoelectric element and a downstream thermoelectric element with the flow channel, wherein the upstream thermoelectric element and the downstream thermoelectric element are arranged spaced apart from each other along an extension direction of the flow channel and movable independent from each other;
• biasing the upstream thermoelectric element towards the flow channel, and independently biasing the downstream thermoelectric element towards the flow channel, wherein the biasing the upstream thermoelectric element includes pressing the upstream thermoelectric element against an exterior wall of the flow channel;
• and
• heating the liquid drug in the flow channel by conducting heat from the upstream thermoelectric element through the exterior wall of the flow channel.