JPH027536U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the configuration of a differential pressure sensor device that is an embodiment of the present invention. FIG. 2 is a diagram illustrating the configuration of another embodiment of the present invention. FIG. 3 is a diagram illustrating the configuration of yet another embodiment of the present invention. FIG. 4 is a configuration diagram showing an example of a conventional differential pressure sensor device. FIG. 5 is a diagram illustrating a buoy indicator. 20: Polarization constant optical fiber, 30, 80, 96:
Optical transmitting/receiving section, 38, 82, 98: optical sensor head section, 58, 66: pressure receiving plate (pressure receiving means), 68: liquid to be measured, LM: measurement light, LR: reference light.

Claims (1)

[Claims for Utility Model Registration] (1) Interference obtained by transmitting and receiving light between an optical transmitter/receiver and an optical sensor head via an optical fiber, and also by causing reference light and measurement light to interfere with each other. In an optical fiber sensor device that performs measurement based on a phase change of light, a pair of pressure receiving means for changing the phases of the reference light and measurement light respectively in response to external pressure are provided at two positions separated from each other in the optical sensor head section. A differential pressure sensor device characterized in that the pressure difference between the two positions is measured based on a phase change of the interference light. (2) The optical sensor head section is immersed in the liquid to be measured with the pair of pressure receiving means facing up and down, and the optical sensor head section is immersed in the liquid to be measured with the pair of pressure receiving means facing up and down, and the optical sensor head section is immersed in the liquid to be measured in a posture in which the pair of pressure receiving means are placed vertically. The differential pressure sensor device according to claim 1, wherein the density of the liquid to be measured is measured. (3) The optical fiber sensor device includes a single transmission polarization optical fiber that transmits light in two transmission modes whose polarization planes are orthogonal to each other, and light for extracting reference light and measurement light having the same frequency. an optical transmitting/receiving unit that detects two types of interference light that are incident on the constant polarization optical fiber and that are returned via the constant polarization optical fiber, and converts them into electrical signals;
The reference light and measurement light are extracted based on the light transmitted by the constant polarization optical fiber, and as the phases of the reference light and measurement light are changed by the pressure receiving means, the light intensity is increased. to the polarization-controlled optical fiber so that two types of interference light whose phases of change are changed and whose phases of the light intensity changes are shifted by 90 degrees are transmitted in two transmission modes of the polarization-controlled optical fiber. It has an optical sensor head section that allows light to enter, and two sensors whose phases are shifted by 90 degrees corresponding to the two types of interference light.
3. The differential pressure sensor device according to claim 1, wherein the pressure difference between the two positions is measured by determining the phase change amount of the interference light based on the types of A-phase and B-phase electrical signals. (4) The optical fiber sensor device includes a single transmission polarization optical fiber that transmits light in two transmission modes whose polarization planes are orthogonal to each other, and the reference light and measurement light are incident on the polarization constant optical fiber. transmit the reference light and measurement light in one and the other of the two transmission modes, and generate interference light based on the reference light and measurement light returned via the polarization constant optical fiber; an optical transmitting/receiving unit that detects a change in the light intensity of the interference light and converts it into an electrical signal; and changing the phases of the reference light and measurement light transmitted by the polarization-constant optical fiber, respectively, by the pressure receiving means; , and an optical sensor head section that makes the reference light and measurement light enter the polarization optical fiber so as to be transmitted in a transmission mode opposite to that of the forward path. Device. (5) The optical fiber sensor device includes a fixed polarization optical fiber for transmission that transmits light in two transmission modes whose polarization planes are orthogonal to each other, and a transmission mode that transmits two types of linearly polarized light whose polarization planes are orthogonal to each other and have different frequencies. the two types of linearly polarized light are transmitted in one and the other of the two transmission modes, and the two types of interference light returned in the two transmission modes of the constant polarization optical fiber are an optical transmitter/receiver that detects each and converts them into electrical signals; and distributes the two types of linearly polarized light transmitted by the polarization constant optical fiber into the reference light and measurement light, respectively;
The frequencies of the reference light and the measurement light are each changed by the pressure receiving means, and the planes of polarization of the two types of linearly polarized light included in either the reference light or the measurement light are rotated by 90° in opposite directions. and an optical sensor head unit that combines the reference light and measurement light and inputs the reference light and measurement light into the polarization-constant optical fiber, and detects the frequency difference between two types of electrical signals corresponding to the two types of interference light. The differential pressure sensor device according to claim 1 or 2, wherein the differential pressure sensor device measures the pressure difference between the two positions based on.