Abstract: A device for sampling a fluid circulating through a system includes: a device inlet; a device outlet; a pressure reducing and/or flow limiting valve or valves between the device inlet and the device outlet for reducing the pressure and/or limiting the flow of the fluid after the fluid enters the device; a flow path altering valve between the pressure reducing and/or the flow limiting valve(s) and the device outlet for receiving the fluid from the pressure reducing and/or flow limiting valve(s) and directing the fluid in a continuous purge flow mode of the device to a first opening of a chamber and through the chamber to the device outlet prior to and after sampling of the fluid: a displacer within the chamber in a continuous purge state when the fluid is directed through the chamber in the continuous purge flow mode; where the flow path altering valve is configured upon activation to change the continuous purge flow mode of the device to a sample discharge flow mode in which the fluid is directed to a second