Patent ID: 8584528

Claim:
A manometer for measuring an internal pressure of a pressure source, comprising: a pressure gauge having an upfront port; an indicator disposed to indicate a measured value that corresponds to a detected fluid pressure measured at said upfront port; a cylinder having a cylindrical chamber which extends in a lengthwise direction to terminate at proximate and distal walls, and which has a cross-section of a first area, said proximate and distal walls respectively having an outlet which is disposed in fluid communication with one of said upfront port and the pressure source, and a guiding bore; a piston configured to be fitted in and fluid-tightly slidable relative to said cylindrical chamber so as to cooperate with said proximate wall to define a fluid subchamber that is in fluid communication with said outlet; a piston rod which is disposed to extend from said piston in the lengthwise direction and outwardly of said guiding bore and terminating at a pressed end, said piston rod having a cross-section of a second area that is smaller than the first area of said cylindrical chamber; and a tubular coupler configured to define a tubular chamber which extends in the lengthwise direction to terminate at a source-side port that is in fluid communication with the other one of said upfront port and the pressure source, and a cylinder-side hole which is in alignment with said guiding bore to permit said pressed end to be fluid-tightly guided into said tubular chamber, a corresponding one of said fluid subchamber and said tubular chamber being disposed to contain a working fluid such that the internal pressure of the pressure source exerting on a corresponding one of said pressed end and said piston is transmitted to said working fluid through said piston.