Fluid measuring device and method

A pressure transducer for measuring pressure in a pipeline, the transducer comprising:

• a sensing tube allowing flow therethrough, wherein the sensing tube has a substantially uniform cross-section for maintaining substantially unobstructed continuous flow through the pipeline and the sensing tube, when coupled to the pipeline, and wherein at least a portion of the sensing tube changes shape by local bulging in response to a pressure on one side thereof;
• a sensor for measuring the changes in shape of the at least a portion of the sensing tube;
• and
• a housing at least partially surrounding the sensing tube.

A method of measuring fluid pressure in a pipeline, comprising:

• at least partially enclosing in a housing a sensing tube which includes a flow passage therethrough;
• installing the sensing tube in line with the pipeline, such that substantially unobstructed flow is provided from the pipeline, through the flow passage of the sensing tube, and back into the pipeline;
• and
• measuring strain in the sensing tube due to local bulging of the sensing tube caused by fluid pressure in the flow passage, as a representation of the fluid pressure.

A pressure transducer for measuring pressure in a pipeline, the transducer comprising:

• a sensing tube allowing flow therethrough, wherein the sensing tube has a substantially uniform cross-section for maintaining substantially unobstructed continuous flow through the pipeline and the sensing tube, when coupled to the pipeline, and wherein at least a portion of the sensing tube mechanically deforms by local bulging in response to a pressure on one side thereof;
• and
• at least four strain gages on the sensing tube for measuring deformation of the at least a portion of the sensing tube;
• and
• wherein at least two of the strain gages are configured for measuring axial strain and another at least two of the gages are configured for measuring circumferential strain;
• and
• wherein the at least two of the gages used for measuring axial strain and the another at least two of the gages used for measuring circumferential strain are connected together in a Wheatstone bridge.