Proton Precession Sensor patent???

[Boattow]

Question for those more in the know than I. I stumbled across this patent while doing a Google search. It is essentially for a toroidal proton mag sensor. This is something that has been around for quite some time. Jim Koehler discusses it in his magnetometer papers and manufacturers have utilized them. In addition this paper discusses and supplies a drawing for multiple cylinders placed at angles. Geometrics has patents on this but I haven't seen them in practical use. All of this for removing the worry of sensor orientation. So this patent was submitted in 2008 and granted in 2011. Would a law suit stand up? Why was this patent granted? Can I patent the wheelbarrow and start suing? If not, why would I spend the money to patent something that I didn't invent?

2nd question, if I wind a cyliner type sensor with thousands of turns of wire, is it a high or low impedance? How would I know this?
Thanks!

http://www.google.com/patents/US20110074408

[Carl-NC]

Just a quick look at the claims tells me they're trying to re-patent old technology. I'd have to read the entire body to see if they are actually trying to achieve something different. This is still in the application stage so it may end up getting thrown out.

[moodz]

These guys seem to place the coil in the container of fluid ... Most prior art seems to wind the coil around the fluid container. How that contributes to supporting the claims I don't know.

[moodz]

...prior art

Serson [1962a] introduced the omnidirectional Toroid sensor, and the author used this shape (see Figure for sounding rocket experiments in the 1970’ies [Olesen, et al., 1976].




Figure 8. Omnidirectional Toroid proton magnetometer sensor. A hollow Acrylic ring with Kerosene and 1000 turns of 1 mm diameter Al-wire. An external electrostatic screen improves the noise immunity of the Toroid. 16 cm overall dimension.
Regardless of the orientation, some parts of the coil will always be perpendicular to the external B-field. The largest signal is obtained when the field is along the symmetry axis, with a factor-of-two decrease in signal amplitude, when the field is in the plane of the ring. (The signal strength goes as (2 - sin2a), where a is the angle between the Toroid axis and the external B-field [Acker, 1971]).

[Willy Bayot]

HI,

All these complexities about winding PPM sensors seem to me to be rather useless in actual practice.
The main aim of those designs are really to avoid potential blind orientations of the sensor but they all require complex and slow winding procedures except if special toroïd winding machines are used.
Actually, in almost all regions of the world (except at some points over the equator), the vertical (Z) vector of the earth magnetic field is strong enough to generate a sufficient proton precession signal in ANY orientation provided the main axis of sensor coils is kept more or less horizontal in order to keep it at 90° from the Z vector.
In the few regions where the main field vector is horizontal, it is sufficient to keep the sensor vertical.

Moreover, the shape of a toroid is not particularly fit to insert into the body of a fish for underwater surveys as it is too fat. The sensor configuration with two noise-cancelling inline coils is much more adequate to give good hydro-dynamic effects.

Placing coils inside the fluid instead of using a fluid container inside the coils aim at providing more fluid (thus, more protons) for the precession process.
When using a fluid like any type of alcohol, there must be taken great precautions to avoid the varnish of the wire to be degraded by the fluid in the long term.
Our experience showed that this was relatively useless as this does not give much gain in signal magnitude.
So, one plastic bottle of fluid inserted inside the core of each coil is more than enough and much simpler to implement.

It is true that the fluid around the coils in the sensor container would make a better protection against pressure than just air for deep underwater surveys.
However, there are now all the necessary material (e.g. thick wall PVC or glass fiber tubing) to build a sensor container strong enough to go down very deep.
In any case, the real weak point of any underwater sensor is the entry of the cable inside the watertight container. There are now some special connectors designed and tested for depths down to 10,000 ft.

Willy

[moodz]

Good points Willy ... I think the point of the toroidal sensor being prior art and now apparently patented illustrates how poor research is nowadays that trivializes the patent system.

[Willy Bayot]

Hi,

The attached picture 1631 shows the pair of coils we provide for underground survey work. They are wound with 18AWG aluminium wire to make them lighter to carry.
The fluid is contained in two plastic bottles inserted in their core and filled with isopropyl alcohol.
The container for that pair of coil is simply a piece of PVC gutter tube with two caps.

The attached picture 1632 shows the pair of coils we provide for underwater survey work. They are wound with 18AWG copper wire to decrease the electrical resistance of the sensor and thus, give a higher polarization current.
The fluid is also contained in two plastic bottles (shown) inserted in their core and filled with isopropyl alcohol.

The attached picture 1633 shows the watertight sensor container we provide for deep underwater surveys. It is rated for depth of 100+ meters (300 Ft).
You can easily see the O-rings inserted in the thick walls of the PVC tube, the two caps screwed on the tube and the hermaphroditic connector rated for depths of 10000+ ft.

At the beginning of our common PPM MarkIV project, James Koehler and I have made a lot of experiments with various coil types and coil arrangements, including toroids and cylindrico-toroids.
The final conclusion of our testings was that the simple cylindrical coils configured as two coils fixed on the same main axis as it is now generalized for all our products is the best compromise in terms of cost/performance.

In all that design, there is no reason for patent. There is no mysterious sensor configuration. The simplest, the best!!!

Willy