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US 5,396,805 AGranted
Force sensor and sensing method using crystal rods and light signals
AssigneeHalliburton Company
InventorJim B. Surjaatmadja
Life of this patent
Estimating the term…
Abstract
A force sensor and a force sensing method use crystal rods as both force responsive elements and light transmission media in combination with light input circuitry and processing circuitry to sense an applied force, such as oil or gas well pressure or fluid flow friction.
Claims12
A force sensor, comprising:
- a first crystal rod having a light input port, a light output port, a light reflective portion and crystalline structure intrinsic to said first crystal rod communicating said light input port with said light reflective portion and communicating said light reflective portion with said light output port;
- a second crystal rod having a light input port, a light output port, a light reflective portion and crystalline structure intrinsic to said second crystal rod communicating said light input port of said second crystal rod with said light reflective portion of said second crystal rod and communicating said light reflective portion of said second crystal rod with said light output port of said second crystal rod;
- light input means for communicating respective light signals into said light input ports of said first and second crystal rods so that each respective communicated light signal travels through the respective said crystalline structure to the respective said light reflective portion and reflects therefrom to the respective said light output port, said light input means including a laser;
- and
- processing circuit means for determining a difference between the light output from said light output ports of said first and second crystal rods, wherein said difference represents a force applied to at least one of said first and second crystal rods;
- wherein said first and second crystal rods are both exposed to a flow of fluid so that both said first and second crystal rods respond to a frictional force of the fluid flow;
- and
- wherein said first and second crystal sensors are disposed parallel to the fluid flow so that said light reflective portion of one of said first and second crystal rods is upstream of said light input port thereof and so that said light input port of the other of said first and second crystal rods is upstream of said light reflective portion thereof.
5 more elements
A method of sensing a force, comprising:
- transmitting a first light signal into a first crystal rod so that the first light signal travels through the first crystal rod, reflects off a reflective portion of the first crystal rod and exits the first crystal rod;
- transmitting a second light signal into a second crystal rod so that the second light signal travels through the second crystal rod, reflects off a reflective portion of the second crystal rod and exits the second crystal rod;
- applying to at least the first crystal rod a force to be sensed so that the length of at least the first crystal rod changes in response to the applied force;
- and
- detecting a phase shift between the first and second light signals exiting the first and second crystal rods, respectively, wherein the detected phase shift is responsive to the change in length of at least the first crystal rod and thus to the force applied thereto;
- wherein said transmitting a first light signal and transmitting a second light signal include transmitting said first and second light signals in opposite directions to each other.
3 more elements
A method of sensing a force, comprising:
- transmitting a first light signal into a first crystal rod so that the first light signal travels through the first crystal rod, reflects off a reflective portion of the first crystal rod and exits the first crystal rod;
- transmitting a second light signal into a second crystal rod so that the second light signal travels through the second crystal rod, reflects off a reflective portion of the second crystal rod and exits the second crystal rod;
- applying to at least the first crystal rod a force to be sensed so that the length of at least the first crystal rod changes in response to the applied force;
- and
- detecting a phase shift between the first and second light signals exiting the first and second crystal rods, respectively, wherein the detected phase shift is responsive to the change in length of at least the first crystal rod and thus to the force applied thereto;
- wherein the force applied to at least the first crystal rod is an oil or gas well pressure.
3 more elements
A method of sensing a force, comprising:
- transmitting a first light signal into a first crystal rod so that the first light signal travels through the first crystal rod, reflects off a reflective portion of the first crystal rod and exits the first crystal rod;
- transmitting a second light signal into a second crystal rod so that the second light signal travels through the second crystal rod, reflects off a reflective portion of the second crystal rod and exits the second crystal rod;
- applying to at least the first crystal rod a force to be sensed so that the length of at least the first crystal rod changes in response to the applied force;
- and
- detecting a phase shift between the first and second light signals exiting the first and second crystal rods, respectively, wherein the detected phase shift is responsive to the change in length of at least the first crystal rod and thus to the force applied thereto;
- wherein:
- said applying a force includes flowing a fluid adjacent the first and second crystal rods;
- and
- said method further comprises disposing the first and second crystal rods parallel to the fluid flow but in oppositely oriented directions.
6 more elements
Dependencies are inferred from the claim text.