Measuring and testing – Fluid flow direction – With velocity determination
Reexamination Certificate
1999-08-24
2001-08-28
Oen, William (Department: 2855)
Measuring and testing
Fluid flow direction
With velocity determination
Reexamination Certificate
active
06279393
ABSTRACT:
BACKGROUND
1. The Field of the Invention
This invention relates generally to fluid flow measurements. More specifically, the invention relates to a system for measuring wind movement in three dimensions, thereby enabling a user to not only measure wind velocity and direction, but other meteorological information which can be derived therefrom, including the measurement of severe wind conditions such as wind shear.
2. The State of the Art
The state of the art in three dimensional fluid flow measurements is replete with examples of devices which attempt to determine the direction and velocity of wind. However, there are many different approaches which have been attempted. Furthermore, these different approaches have been met with varying degrees of success. In addition, some of these approaches are not suitable for severe weather conditions.
A brief examination of some of the prior art is provided in order to illustrate some of the shortcomings thereof. Beginning with U.S. Pat. No. 3,359,794 issued to Rosenberg, the patent apparently teaches a plurality of thermistors which are coupled to the outside of a sphere. The thermistors measure an increasing temperature of the fluid (in this case water) as it flows around the current meter. This information is used to determine a flow direction and velocity. It is observed that the fluid must be of a type which will measurably rise in temperature as it flows around the sphere. Among other things, a substantial number of thermistors must be used. The patent also states that it is specifically intended for determining current data for a liquid.
In U.S. Pat. No. 3,695,103 issued to Olson, the patent teaches a buoyant sphere which is floating in a medium (liquid). The sphere is tethered to cables which have strain gauges. This application is also directed to liquid applications.
In U.S. Pat. No. 4,488,431 issued to Miga, the patent teaches a wind speed and direction device which is very similar to anemometers such as the one shown in FIG.
1
.
FIG. 1
is provided to illustrate the problems with a state of the art anemometers
2
and wind vanes
4
. For example, because it is mechanical, light wind conditions might not overcome the frictional component of the wind vane. The result is an increasingly incorrect and sluggish response of the vane
4
. As is typical of mechanical sensors, they become non-responsive or slow to respond at low wind speeds. The anemometer
2
suffers from being inaccurate in light wind conditions, and being slow to respond to quickly changing conditions. Furthermore, both devices can easily fail in severe weather conditions such as icing or snow.
In U.S. Pat. No. 4,920,808 issued to Sommer, the patent teaches a device for measuring wind direction and velocity. However, the method and apparatus are unnecessarily complicated by the use of a body other than a sphere. Among other things, the patent also teaches having different systems for determining flow direction and velocity. For example, the device requires a servo-motor and other high maintenance parts for determining direction of flow, and other sensors for calculating the velocity.
There are other teachings in U.S. Pat. No. 4,631,958 issued to Van Cauwenberghe et al, in U.S. Pat. No. 4,635,474 issued to Blackwood, and in U.S. Pat. No. 5,117,687 issued to Gerardi, all of which operate using different principles of operation, and which are designed to determine wind velocity and direction.
What is needed is a system for isotropically measuring the direction and velocity of wind which is substantially less complicated than the prior art. It would be another advantage if the system could also be modified to withstand the elements so that measurements can be made in hostile environments. What is also needed is a system which can be linked together from a plurality of measurement stations to thereby use data which is accumulated about a larger area to thereby make predictions and/or actual measurements of dangerous wind conditions such as wind shear by extrapolating data therefrom.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a system which accurately and inexpensively measures wind direction and velocity.
It is another object to provide a system which can measure wind direction and velocity using a sensor which does not have moving parts.
It is another object to provide a system which in addition to wind data, can also determine other atmospheric conditions, including pressure, temperature and relative humidity.
It is another object to provide a system which measures wind direction and velocity by measuring and analyzing pressure differentials on the surface of a sphere.
It is another object to provide a system which determines wind direction and velocity using differential orthogonal pressure measurements.
It is another object to provide a system which determines wind direction and velocity by utilizing three orthogonal axis pressure measurements to thereby determine both the horizontal and the vertical components of air motion.
It is another object to provide a system which determines wind direction and velocity which utilizes a sphere having apertures through which air is able to pass.
It is another object to provide a system which determines wind direction and velocity which utilizes a sphere having no apertures in the surface.
It is another object to provide a system which determines wind direction and velocity which is able to operate in severe and hostile environments.
It is another object to provide a system which determines absolute and time varying quantities of pressure, temperature and humidity.
It is another object to provide a system which determines wind direction and velocity in a localized area which can be used to detect short term but severe wind conditions.
It is another object to provide a system which determines atmospheric conditions including wind direction and velocity, to thereby generate a three-dimensional description of air and weather patterns in the local area.
It is another object to provide a system which determines the direction and velocity of any fluid which is capable of flowing around a measurement sphere, and producing differential pressures.
The present invention is a system for measuring wind direction and velocity utilizing a sphere which is capable of making differential orthogonal pressure measurements, using pressure sensors located inside the sphere along apertures forming orthogonal axes of the sphere. The preferred embodiment applies the Bernoulli principle to the sphere which has the apertures disposed along the orthogonal axes, and which measures the wind velocity and direction, whereas an alternative embodiment applies the Reynold's principle by using a sphere having no apertures therein, and resulting in a more robust meteorological measurement device which can also measure other meteorological data which is combined with the wind data to produce forecasting of air and weather patterns in a localized area.
In a first aspect of the invention, the preferred embodiment applies the principle that pressure differences occur on opposite sides of the sphere and along the axis of the flow, and that the pressure difference is a function of the velocity and the viscosity of the flow and the angle difference with respect to the points of measurement of the sphere.
In a second aspect of the invention, the sphere with apertures along orthogonal axes generally operates on the Bernoulli principle, where a sphere having three bipolar pneumatic ports is used to directly measure the vector pressure differentials as seen isotropically over the entire surface of the sphere.
In a third aspect of the invention, the sphere has no apertures therethrough, but generally operates on the Reynolds principle, where the sphere is disposed upon a set of orthogonally arranged gimbals, and which utilizes three bipolar variable reluctance linear reactors which interface the sphere to the gimbals and thereby react to isotropic forces imposed upon the sphere by fluids flowing therearound.
These and other
Morriss Bateman O'Bryant & Compagni
Mountain High E&S
Oen William
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