Brake check handheld refractometer
AssigneeLeicaMicrosystems, Inc.
InventorsChristopher T. Cotton, Jeffrey M. Sabin, Thomas E. Ryan
Life of this patent
Estimating the term…
Abstract
A refractometric apparatus and method for monitoring the percentage of water in hydraulic fluids employ a temperature sensitive device allowing a user to obtain accurate and correct readings of various measured properties on the reticle of the apparatus. In particular, the temperature sensitive member comprises a prism-wedge-mirror combination in conjunction with a bimetallic strip. The combination ensures the proper angular displacement of a light beam inside the refractometric apparatus and, therefore, the correct readings on the reticle.
Claims65
A refractometric apparatus for use with a hydraulic fluid, comprising:
- means for defining an optical path;
- a reticle located along the optical path;
- a prism located along the optical path in spaced relation to the reticle, the prism having a face disposed toward a sample of the hydraulic fluid, the prism being located to receive light for illuminating the sample of the hydraulic fluid, whereby a transition between light and darkness is a function of a water content in the hydraulic fluid;
- a reflecting element located along the optical path between the prism and the reticle;
- and
- a temperature sensitive meanies operatively engaging the reflecting element for pivotal motion of the reflecting element in response to temperature changes so as to compensate for temperature changes by altering the optical path in response to such changes;
- whereby the reticle provides a reading relating to the water content of the hydraulic fluid.
A refractometric apparatus for use with hydraulic fluids, comprising:
- means for defining an optical path;
- a reticle located along the optical path, the reticle further comprising markings that increase in the direction of increased water content in the hydraulic fluid;
- a prism located along the optical path in spaced relation to the reticle, the prism having a face disposed toward a sample of the hydraulic fluid, the prism being located to receive light for illuminating the sample of the hydraulic fluid, whereby a transition between light and darkness is a function of a water content in the hydraulic fluid;
- a second prism located along the optical path between the prism and the reticle, the second prism having a face covered by a reflective coating;
- and
- a temperature sensitive means operatively engaging the second prism for pivotal motion of the second prism in response to temperature changes so as to compensate for temperature changes by altering the optical path in response to such changes;
- whereby the reticle provides a reading relating to the water content of the hydraulic fluid.
A refractometric apparatus for use with a hydraulic fluid, comprising:
- means for defining an optical path;
- a reticle located along the optical path;
- a prism located along the optical path, the prism having a face disposed toward a sample of the hydraulic fluid, the prism being located to receive light for illuminating the sample of the hydraulic fluid, whereby a transition between light and darkness is a function of a water content in the hydraulic fluid;
- a reflecting element located along the optical path;
- and
- a temperature sensitive means for engaging the reflecting element in pivotal motion, wherein the temperature compensation is selected to correspond to a temperature coefficient of a hydraulic fluid within a range of -30.times.10.sup.-5 /.degree. C. to -50.times.10.sup.-5 /.degree. C.;
- whereby the reticle provides a reading relating to the water content of the hydraulic fluid.
A method for measuring water content in a hydraulic fluid for use with an apparatus comprising means for defining an optical path, critical angle prism, the critical angle prism having a face, a temperature compensation means, and a reticle disposed along the optical path, the method comprising the steps of:
- placing the hydraulic fluid on the face of the critical angle prism;
- allowing light to enter the optical path through the hydraulic fluid;
- compensating for temperature changes by altering the optical path in response to the ambient temperature;
- and
- observing a boundary between light and darkness on the reticle to measure water content of the hydraulic fluid.
In a method of measuring water content in a hydraulic fluid for use with an apparatus comprising means for defining an optical path, a critical angle prism, the critical angle prism having a face, a temperature compensation means, and a reticle disposed along the optical path, a calibration method comprising the steps of:
- placing the hydraulic fluid on the face of the critical angle prism, the hydraulic fluid being of a known water content;
- allowing light to pass through the hydraulic fluid and to enter the optical path;
- and
- adjusting the optical path so that a boundary between light and darkness on the reticle impinges upon the reticle at a predetermined point.
A method of measuring water content in a hydraulic fluid for use with a plurality of apparati, each apparatus comprising means for defining an optical path, a critical angle prism, the critical angle prism having a face, a temperature compensation means comprising a reflecting element and a temperature sensitive element operatively engaging the reflective element for pivotal motion, and a reticle disposed along the optical path, the method comprising the steps of:
- selecting an apparatus according to the hydraulic fluid to be measured;
- placing a sample of the hydraulic fluid on the face of the critical angle prism, the hydraulic fluid being of a known water content;
- allowing light to pass through the hydraulic fluid and to enter the optical path;
- and
- observing a boundary between light and darkness on the reticle to measure the water content in the hydraulic fluid.
A method of measuring a water content in a plurality of types of hydraulic fluids for use with an apparatus, the apparatus comprising means for defining an optical path, a critical angle prism, the critical angle prism having a face, a reticle disposed along the optical path, a temperature sensitive means disposed along the optical path, and an adjustment means for selecting a type of a hydraulic fluid, the method comprising the steps of:
- adjusting the adjustment means to correspond to the type of the hydraulic fluid;
- placing the hydraulic fluid on the face of the critical angle prism;
- allowing light to enter the optical path through the hydraulic fluid;
- compensating for temperature changes by altering the optical path in response to the ambient temperature;
- and
- observing a boundary between light and darkness on the reticle to measure the water content in the selected hydraulic fluid.
A kit for measuring water content of a hydraulic fluid, comprising a refractometric apparatus, comprising:
- means for defining an optical path;
- a reticle located along the optical path;
- a prism located along the optical path in spaced relation to the reticle, the prism having a face disposed toward a sample of the hydraulic fluid, the prism being located to receive light for illuminating the sample of the hydraulic fluid, whereby a transition between light and darkness is a function of a water content in the hydraulic fluid;
- a reflecting element located along the optical path between the prism and the reticle;
- a temperature sensitive means operatively engaging the reflecting element for pivotal motion of the reflecting element in response to temperature changes so as to compensate for temperature changes by altering the optical path in response to such changes;
- and
- user instructions directing a user to place hydraulic fluid on the first surface.
A refractometric apparatus for use with a hydraulic fluid, comprising:
- means for defining an optical path;
- a reticle located along the optical path;
- a prism located along the optical path in spaced relation to the reticle, the prism having a face disposed toward a sample of the hydraulic fluid, the prism being located to receive light for illuminating the sample of the hydraulic fluid, whereby a transition between light and darkness is a function of a water content in the hydraulic fluid;
- a reflecting element located along the optical path between the prism and the reticle;
- a temperature sensitive means operatively engaging the reflecting element for pivotal motion of the reflecting element in response to temperature changes so as to compensate for temperature changes by altering the optical path in response to such changes;
- and
- an adjusting means for altering the optical path to correspond to each of a plurality of types of the hydraulic fluids;
- whereby the reticle provides a reading relating to the water content of the hydraulic fluid.
Dependencies are inferred from the claim text.