THERMAL FLOW SENSOR

The invention relates to a flow sensor (1), comprising: a semiconductor module (2) on which a temperature sensing means (13a, 13b) and a heat source (12) are arranged, a flow channel (6) for guiding the fluid medium in a flow direction (D), and a wall (W) delimiting the flow channel, wherein said heat source (12) and said temperature sensing means (13a, 13b) are configured such that they are in thermal contact with said wall (W). According to the invention, said wall (W) comprises a glass member (4) and a metal member (3a), wherein the glass member (4) is connected to the metal member (3a). The glass member (4) is connected to the metal member (3a) via a junction (J) such that a recess (43) of the glass member (4) is fluidly connected to two through holes (301, 302) of the metal member (3a), so that said flow channel (6) extends from one through hole (301) forming an inlet of the flow channel (6) via the recess (43) of the glass member (4) to the other through hole (302) which forms an outlet of the flow channel (6). Due to the fact, that the junction J extends circumferentially around the two through holes, the flow channel is sealed by means of the connection between the glass member (4) and the metal member (3a). The semiconductor module (2) comprises a recess (23) on the first side (21) which comprises thin a bottom (24), where the heat source (12) and said temperature sensing means (13a, 13b) are at least partially arranged, so that they are in thermal contact with the glass member (4). For connecting the semiconductor module to the outside world, the semiconductor module (2) comprises electrical contacts (25) which are each connected to a flexible conductor (53) via a solder junction (51). Alternatively or in addition, the flow sensor (1) comprises a transmitter (T) for transmitting data measured by the flow sensor in a wireless fashion to a remote receiver and a battery (B) for powering the components of the flow sensor (1). The housing (3) preferably encapsulates all components of the flow sensor (1), which may be a stand-alone device, but may also form a part of an implant or a medical device such as a catheter or a micro dosing pump. The metal member (3a) forms at least a part of said housing and is made preferably from titanium or steel. The problem underlying the present invention is to provide a flow sensor of the aforementioned kind that reliably shields the components of the flow sensor from the medium to be measured and can particularly be