Radar level gauge with high temperature, high pressure (HTHP) process seal

A radar level gauge using electromagnetic waves for determining a filling level of a product in a tank, said radar level gauge comprising:

• a transceiver for transmitting an electromagnetic transmit signal and receiving an electromagnetic echo signal;
• processing circuitry connected to said transceiver for determining said filling level based on said electromagnetic echo signal;
• a directional antenna for directing said electromagnetic transmit signal towards a surface of said product and to return a reflection from said surface as said electromagnetic echo signal;
• a hollow wave guide connecting said transceiver with said antenna,
• a tank connection arranged to be sealingly secured to the tank, said fixed tank connection having a through hole with an annular abutment;
• a dielectric filling member arranged in the tank connection and configured to prevent entry of tank content into the antenna and/or hollow wave guide, the dielectric filling member comprising an annular collar portion resting against said annular abutment;
• a clamping member inserted into the tank connection, such that the annular collar portion is sandwiched between the annular abutment and the clamping member;
• a fastening member attached to said fixed tank connection thereby securing said clamping member between said fastening member and said annular abutment;
• and
• a spring member arranged between said fastening member and said clamping member, and configured to press said clamping member towards the annular abutment, so as to apply a sufficiently controlled pressure on said annular collar portion, such that said annular collar portion in itself provides a pressure tight sealing between a tank interior and a tank exterior.