White, J. A.

English

NASA Technical Reports Server

March 13, 1962 J. A. WHITE 
MAGNETICALLY CENTERED LIQUID CaLmN FMAT 
Filed Sept. 12. 1958 
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F /G. FIG. 2 
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FIG. 5 
FIG. 4 
lNVENTOR 
JAMES A. WHITE 
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I N (THRU) ATTORNEYS 
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9 (PAGES) 
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(NASA r d R  AD NUMMR) 2 
https://ntrs.nasa.gov/search.jsp?R=19700025504 2020-03-17T02:00:39+00:00Z
3,024,659 United Stares Patent Office ,an &, ,, ,, 
1 2 
3,024,65 9 The float 13, in the arrangement of P I S .  1, "end 3 
MAGNETICALLY CIENTEmD LXQWfi and assuming an application uf alternating current, io 
COLUMN FLOAT an electricatly conducti~tg metal, suc1.1 as copper, the float 
James A. We~ite, Lss Altos, Calif., assignor, by mesne forming a core in the space between the ~01:s 24 end IS. 
assimments, to the United Slates of America as repre- 5 Under the influence of the applied electromagl~etic fiux, 
sented by the Adminiskator of the NaMonal h r o -  eddy currents are induced in this metal float, the direc- 
naugics and Space Administration rion of eddy currents being such as to result in repulsion 
Filed Sept. 12, 1958, Ser. ~ T Q .  760,819 forces in respect to the magnetizing co~ls, with the result 
4 Claims. (Cl. 73-401) that the float is shifted centrally is a point of force (Granted under 357 U's' (1852)9 set' 266) 10 equilibrium avith reference to the magnetic flux. 
Tfie invention described herein may be manufactured Consequently, the float, physically is held centrally in the 
and used by or for the Government of the United States manometer tube and, in up and down rnovjment thereof, 
of America for governmental purposes without the pay- all frictional contact is eliminated. 
merit of any royalties thereon or therefor. In FIG. 4, a modification of the invention is disclosed 
This invention relates to a liquid column float which 16 wherein the float 25 consists of a permanently magneti7~d 
is automatically centered in the liquid, this float having core of steel, or nickel, or alloys containing one or more 
special adaptation for use with manometers. of these metals, and the magnetizing means one or more 
Floats have been used in manometer tubes, for ex- permanently magnetized magnet 26 external tcr and ad- 
ample, in which iron or other magnetic substance has jacent the tube in the region of float movement. The 
been incorporated and this iron has been utilized in 20 polarity of the permanent magnet and core float are as 
association with electrical circuits to indicate automatically indicated in the drawing (FIG. 4 )  producing an opposing 
the height of a liquid column in the tube. A difficulty magnetic flux and insuring a centering of the float. 
present in the prior manometer lies in the fact that in The arrangement of FIG. 5 employs an inducing coil 
the up and down movement of the float, contact of the 30 energized by direct current. The float is shown in 
float with the tube wall involves a certain amount of 26 this figure as consisting of a permanent magnet 33 in 
friction resulting in a clearly defined error in the the float body 32. Tile permanent magnet should nor- 
manometer reading. mally extend above and below the coil 30 in order to 
A primary object, therefore, of the invention is to minimize vertical forces. This core, when the tube ma- 
eliminate friction between the movable float and the wall terial is iron, lends itself to joint use with automatic 
of a manometer tube. Another object is to eliminate 80 level indicating means such as the automatic liquid col- 
use of mechanical centering devices for tube floats. umn manometer described in the patent to Waldo H. 
Other objects and many of the attendant advantages Kliever, Patent No. 2,357,745 wherein a coil follower 
of this invention will be readily appreciated as the same moves up and down the manometer in magnetic flux 
becomes better understood by reference to the following equilibrium with an iron float. 
detailed description when considered in connection with 36 FIG. 6, also, employs a peripheral coil 40 about the 
the accompanying drawings wherein: tube 11, the coil in this modification being supplied by 
FIG. 1 is a sectional fragmentary view of a section alternating current and the core 41 consisting of non- 
of a manometer tube containing the supporting liquid magnetic metal for eddy current development. 
and float and indicating the coil float centering means; Obviously many modifications and variations of the 
FIG. 2 is a side elevation of the tube of FIG. 1; 40 present invention are possible in the light of the above 
FIG. 3 is a plan view of the manometer elements taken teachings. It is therefore to be understood that within 
along lines 3-3 of FIG. 1 ; the scope of the appended claims the invention may be 
FIG. 4 is  a vertical view of a manometer float section practiced otherwise than as specifically described. 
showing a permanent magnet control; What is claimed is: 
FIG. 5 is a sectional fragmentary view showing a 1. In a manometer, a liquid level indicating device 
direct current coil applied to a permanently magnetized *' comprising a tube containing the liquid, a float member 
float; and positioned in said liquid to be freely axially displaceable 
FIG. 6 is a sectional fragmentary view showing an in said tube, said float member being buoyant in said 
alternating current coil applied to a soft iron float. liquid and being constrained against rotary motion by 
References may now be made to FIG. 1 in which 60 the viscosity of said liquid, means external to said tube 
appears a vertical section of a conventional manometer to establish a first magnetic field in said tube, and internal 
10 including a tube 11, the tube containing a suitable means comprising the material of said float for establish- 
liquid 12, as mercury, and a float 13 supported on the ing a second magaetic field having a direction with re- 
upper surface or menisclls of the mercury. On opposite spect to said externally established magnetic field such 
sides of tube 11 are wire coils 14 and 15, each coil con- 65 that repelling forces are established between said first and 
sisting of a number of insulated wire conductors 16 (FIG. second magnetic fields to radially center said float in 
3) wound in elongated rectangular form to constitute an said tube. 2. Apparatus as in claim I wherein said external mag- induction coil, the terminal leads 20 and 41 of one of 
netic field establishing means is a magnet and the coils being indicated in FIG. 2. These coils 14 and said float comprises a permanent magnet with its 
15 are connected electrically together, either in parallel 60 oriented the same as those of the external magnet. 
or series, to a common electric source, the polarity of 3. A~~~~~~~~ as in claim wherein said mag- 
the connections being such as to give for direct current netic field establishing means is a coil excited by direct 
or for one alternation of alternating current, the direc- current and said float comprises a magnet 
pion of flow indicated in FIG. 3. Preferably, the coils having its poles oriented the same as the polarity of said 
14 and 15 should be elongated to the extent that the externally generated field. 
magnetic effects of the cross wires 17 and 18 relative 4. Apparatus as in claim 1 wherein said external field 
to the float are effectively reduced. establishing means is a coil excited by alternating sur- 
3,094,659 
3 4 
rent and said float comprises a nonmagnetisable metal of 2,436,939 Schug ---,------------- Mar. 2, 1948 
low electrical resistance in which eddy currents are gen- 2,558,118 Vost --------,--------- June 26, 1951 
erated by said first magnetic field. 2,747,944 Baermann ------------ May 29, 1956 
References Cited in the file of this patent Q 
UNITED STATES PATENTS 
2,357,745 Kliever -----,---------- Sept. 5, 1944 
FOREIGN PATENTS 
839,876 Germany -------------- May 26, 1952 


Magnetically centered liquid column float Patent

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