Differential pressure assembly with protective boot and arrangement for amplifying pointer

A differential pressure meter comprising:

• an elongated tube having a proximal inlet and a distal inlet;
• a boot in the elongated tube, the boot having:
• an open proximal end aligned with the proximal inlet for receiving a primary flow;
• an intermediate bellows section in fluid communication with the open proximal end;
• and a closed distal end;
• a magnet coupled to the closed distal end;
• and
• a spring in the elongated tube for providing a bias force opposing the intermediate bellows section,
• wherein the boot and spring are configured in balance so that variation between the primary flow and a secondary flow into the distal inlet moves the magnet as a function of the variation while the boot prevents mixing of the primary and secondary flow.

A differential pressure meter comprising:

• a tubular housing defining a chamber having a first and second pressure inlet;
• a protective boot situated in the chamber between the first and second pressure inlet, the protective boot having a bellowed profile configured for extension and retraction in the chamber, the protective boot connecting to the tubular housing at a proximal end, the protective boot defining a magnet chamber at a distal end;
• a first magnet situated in the magnet chamber of the protective boot;
• and
• a pointer assembly having an effort arm and a load arm, the effort arm coupled to a magnet holder housing a second magnet, the load arm engaging teeth of a pinion, the pinion coupling to a pointer of a gauge,
• wherein:
• the protective boot extends or retracts within the chamber based on a differential pressure between the first and second pressure inlet, driving the first magnet axially, and
• the first magnet is configured to interact with the second magnet to shift the effort arm and consequently the load arm of the pointer assembly, thereby moving the pointer of the gauge.