Abstract: A sampling device configured to extract a sample from a fluid flow such as an oil flow. The sampling device has a sample extraction channel to extract the sample from the fluid flow, sample extracting device configured to press a sample into the sample extraction channel, and a check valve in the sample extraction channel. The check valve has a valve seat and a sealing device movable with respect to the valve seat between a closed position, in which the sealing device sealingly engages the valve seat and an open position in which the sealing device is spaced from the valve seat to allow fluid flow between the valve seat and the sealing device. The sealing device and the valve seat may have first seal element and a second seal element to engage in the closed position with the other.