Pressure transducer
OwnerDwight N. Johnsoninventor
Life of this patent
Estimating the term…
Abstract
A pressure transducer which has a closed chamber which is full of oil or other non-compressible liquid. Pressure communicates with a diaphragm which defines one side of the closed chamber and the pressure communicates via the oil with a pressure sensor which is mounted within the oil spaced from the diaphragm. The liquid entered the closed chamber through a inlet hole with a selected volume driven into the closed chamber by a ball which is forcefully driven a selected distance into the inlet hole before stopping at the end of the inlet hole against a physical stop.
Claims4
A method of making a pressure transducer having a closed chamber having a flexible flat diaphragm defining one side, a support cup including a flat base mounted within the closed chamber with the flat base parallel to and selectively spaced from the diaphragm, a pressure sensor mounted within the closed chamber, the closed chamber including an inlet bore including an outer enlarged diameter portion, a first reduced diameter portion extending a selected distance inwardly from said enlarged diameter portion towards said closed chamber ending at a second further reduced diameter portion, and a pressure supply path means for delivering fluid pressure from a hole in a pressurized pipe to the diaphragm including a piercing needle, support means for supporting the piercing needle for displacement into a pipe to pierce the pipe, and bore means extending from a first location surrounding the piercing needle to a second location communicating with the diaphragm the method comprising
- applying a preload pressure to the pressure supply path to displace the diaphragm from its relaxed state to a deflected position against the flat base to reduce the volume of the closed chamber by a selected volume,
- while maintaining the preload pressure applying a vacuum to the inlet bore by opening a valve to remove air from the chamber,
- after a vacuum is established, closing the valve and filling the chamber with oil at least to the juncture of the first reduced diameter portion of the inlet bore and the enlarged diameter portion of the inlet bore,
- forcing a ball smaller than the enlarged diameter portion and larger than the first reduced diameter into said first reduced diameter portion until the ball rests against the second further reduced diameter portion with the volume of oil pushed into the closed chamber being predetermined to be equal to said selected volume so that the when the preload is removed, the diaphragm will be at its relaxed state, and
- removing the preload pressure.
A pressure transducer comprising
- a closed chamber having a diaphragm defining one side,
- a pressure sensor mounted within said closed chamber with a space separating the pressure sensor and said diaphragm,
- an inlet bore communicating with said closed chamber including
- an outer enlarged diameter portion,
- a first reduced diameter portion extending a selected distance inwardly from said enlarged diameter portion towards said closed chamber terminating at a second further reduced diameter portion,
- a ball wedged into said first reduced diameter portion against said second further reduced diameter portion, and
- a non-compressible liquid filling said closed chamber,
- said diaphragm being in the relaxed state.
Dependencies are inferred from the claim text.