Modular transmitter with flame arresting header

A transmitter for sensing a pressure of a process fluid comprising:

• sensing means disposed within the transmitter for providing an output representative of pressure;
• a header having a chamber on an outer face and a passageway extending from the chamber to a tapered opening inside the transmitter, the passageway having a first portion adjacent the tapered opening shaped to receive an inlet tube leading to the sensing means and having a second flame isolating portion open to the chamber;
• a diaphragm transferring the pressure of the process fluid acting on an outer surface of the diaphragm to a substantially noncompressible fill fluid that isolates an inner surface of the diaphragm, the fill fluid filling the chamber, the passageway and the inlet tube, and the pressure of the fill fluid being sensed by the sensing means, where an outer periphery of the diaphragm is sealingly attached to the outer face of the header;
• and
• a seal in the tapered opening around the inlet tube for sealing in the fill fluid, the flame isolating second portion of the passageway being shaped to provide flame isolation for flame isolating the tapered seal around the inlet tube and an interior of the inlet tube from the process fluid.