US2234421A - Float control - Google Patents

Description

11, 1941. L TURNER 2,234,421

FLOAT CONTROL Filed June 4, 1938 Patented Mar. 11, 1941 UNITED STATES PATENT OFFICE "l Claim.

This invention relates to improvements in float controls. More particularly, it relates to improvements in the type of control disclosed by my co-pendng application Serial Number 33,796

3 illed July 29, 1935, now Patent No. 2,120,048

granted June "I, 1938.

The present control embodies the features of a container having a lower chamber accessible to the liquid whose level is to be controlled and an L) upper chamber completely sealed oil' from the lower chamber. In the lower chamber is a float member comprising an armature member movable within a tube extending upward from the lower chamber into the upper chamber. Surrounding the upper end of the tube is a coil forining part of a circuit comprising means arranged to effect the opening or closing of a control valve or other electrical agency.

It is among the objects of the present invention to provide a simple, compact unit comprising the float and the coll and a simple circuit whereby the electrical reactions of the coil may be effectively utilized.

The best mode in which I have contemplated 95 applying the principles of my present invention is shown in the accompanying drawing, but these are primarily illustrative for it is intended that the patent shall cover by suitable expression in the appended claim whatever features of patentable novelty exist in the invention disclosed.

In the drawing: Figure l is a vertical medial section through my improved control, the float member being shown in elevation; Figure 2 is a section taken as on line 2--2 of Figure l; and

Figure 3 is a diagrammatic showing of the preferred electrical circuit to be employed with the control. Referring particularly to Figures 1 and 2, the unit container comprises a bottom shell I. with side outlets 2 and 3 and a bottom outlet 4. The upper side outlet 2 is connected by a pipe 5 to the receptacle holding a liquid above any high level which the liquid would normally reach. Either the other side outlet 3 or the bottom outlet 4 should be connected to the said receptacle below any low level which the liquid could normally reach. As here shown, the lower side outlet 3 is indicated as so connected by pipe 8 and the bottom outlet 4 is closed by a plug 'L The upper end ia of the bottom shell l is preferably cast somewhat thicker than the wall to provide an ample seat for an intermediate partition l. This partition has a. flange Ga nicely fitting within the end la to which. 'the partition is secured by the bolts 5. At the center of the partition is a threaded hub 8b having on its under side a rounded rim 8c. Within the lower end of this hub is screwed a disk or bushing i0 of stain- 5 less steel having a central hole or opening ina. Into the upper end ci the hub 8b is screwed a tube Il of low magnetic permeability which extends upward and has its upper end closed oy a stud i2 of special design. This stud has s cyiiri- 1 drical portion i2a nicely iitting the bore of tube yand a flanged shoulder 12b engaging the upper edge of the tube. This upper edge and the shoulder are welded together as shown at i3. The

upper end or threaded stem I2c of the stud exxq' tends through a hole Ha in the top ot an upper shell Il of the unit container. This shell has a reduced bottom edge Hb which iits nicely on a recessed edge 8d of the intermediate partition so that the external side sui-races er the bestem shell 20.

l, the intermediate partition 8, and the upper shell i4 are in alignment. A nut i5 on the stud I2 Secures the upper shell i4 firmly to the intermediate partition. A threeded hole ido in the side of the upper shell is provided for the inser- 25 tion of a suitable hollow plug through which ex tend Waterproof cables i6 and il.

These wires lead to a coil i8 which is wound about a tube l5 of insulating material; the latter tube fitting nicely around the herelnbeiore d..- 30 scribed tube il. Around the coil is an insulated l shell il! which is preferably formed by dipping the coil in a bath of molten insulating material.,

Ato form a coating thereof around the coil, after which the coil is removed from the beth and the ,35 y 'insulated shell 20 permitted to harden. -Arourid the insulated shell of the coil is a. metal shell il oi high magneticA permeability. This metallic shell is shown as having a cylindrical wail and end covers 2id and 2lb each provided with a i0 flanged edge to snugly fit around the ends of the cylindrical wall. ".lhese covers are provided with l central holes Whose edges tit nicely around the' inner tube il. v Collars 22, Witheet screws 23 are provided at each end of the coil assembly to per- 4i5 hola idd near the top or the shell which. is later' g closed by a plug. Thus when completely assembled, the coil and its electrical and magnetic ad- .juncts are completely waterprooed. Should. it:

become necessary to readjust the position of the coil and to do anything else to the parts within 'and poured out by the shell it, the paran can be readily melted holding the control upside down, .Within the lower shell l is a hollow lball or iioat 2d to which is connected a rod 2li extending `r`upward through the hole lila of the stainless vsteel guide disk lll. On the upper end'of this rod is mounted an armature :member 2, also of high magnetic permeability. When the level of liquid in the receptacle and in the bottoni shell l v is at some low level, auch :c--ze for example,

the oat 2li is near the lower end 'ci the shell, indeed may be resting onthe rcunded'rlrn lb oi' the bottom outlet 6. When the liquid rises to.

` some predetermined upper level, as for example y1v, the oat rises land effects movement of the armature it to a position within the coil it, for example the position sl'lotvnl dotted in Figure l. is will nowy be described this eects a the primary winding '2da oi a transformer 223.

A secondary circuit comprises the wire it leading` from one end of the secondary winding Elib of this transformer to the coil iti. From the latter the wire il leads, as here shown, to a low capacity relay 2Q and from the latter a wire 3@ returns to thesecondary winding ib of the transformer.

Between the wires l and il is connected a condenser 3i. The electrical characteristics of the coil iii and condenser di are such that when the movable armature 2t is within the coil id, for example in the position indicated in Figure l by the dotted outline, the secondary circuit is in a condition of resonance. When in this condition there is no eective flow of current in the secondary circuit, certainly not enough to energlze the relay Accordingly, the armature switch 32 will be drawn away from the coil of the relay by the spring Thus a third circuit vis open.

This third circuit comprises a wire 3d leading from wire l@ to a high capacity relay B5, this said relay, a wire Se leading thence to the armature switch 32, `this said switch, and a wire ill connecting the latter to wire Sii. Since this circuit is broken when switch 32 is open, the relay 35 is`not energized and thus its armature switch 3B is drawn away from the relay by a spring lib. Thus a fourth circuit is open.

This fourth circuit comprises a wire il@ leading from the wire Za of the main power line to the armature switch 38, this said switch, a wire il leading thence to a solenoid coil 32 and a connection i3 from the latter to the other wire 2l of the main power line. The solenoid l2 is here shown as controlling the position of a valve ld in the supply line 65 for the liquid which is fed to the container wherein the level of liquid is to be controlled; instead of a valve, lt is obvious that the solenoldmight berutilized toactuate any other responsive agency. j

'Upon the liquid falling to some level such as 'zr--ag Figure l', thereby edecting the withdrawal oi the armature 2e from the coil it, the coli and condenser si will' no longer be in resonance, thereby permitting an appreciable current flow through the secondary circuit sucient to energize relay 29 and close the switch 32. This will establish ow through the third circuit and energize relay 35 to close switch 38. Closure of this switch closes the fourth or direct circuit from the power lines to the solenoid d2 and opens valve tl. This condition of the circuits is shown in Figure 3.

The valve lli being thus open, the liquid inthe container will rise until some level, such as 1l-y, is reached where the movable armature 26 is again within the coil lli. i

The high magnetic permeability of the armature 2S together with the high magnetic perineability ci?. the metallic shell 2l (2id and 2lb) surrounding thecoil, favors a ow of magnetic flux which appreciably affects the electrical characterlstic of the coil :by changing its impedance.

' When so aected, its electrical characteristic becomes such that, in conjunction with the con-v denser 3l,l the secondary circuit is in a condition of resonance, and thus the e'ective ow through the n secondary circuit is reduced to the point where the relay 29 is not sufficiently energized to overcome the force of spring S3 and the switch 32 will thereupon be opened. Thence follow the closure of valve lli, as previously described, with consequent shutting oi of the liquid ow through supply line l5 to the container. Thus the control restores the liquid level under control.

I claim:

Electric iioat control apparatus comprising a vertically disposed xed tubular member of low magnetic permeability having its upper portion surrounded by a coll; a magnetic conductor of high magnetic permeability arranged externally of said coil; a transformer connected to a source of alternating electric current; a circuit connected to the secondary winding of said transformer and including said coil and a relay and a condenser arranged in the circuit in parallel with said coil; and a floating armature member of high magnetic permeability movable within said fixed tubular member into and out of the path of magnetic iiux of said coil in accordance with changes in the level of a liquid; the said coil and said condenser having such relative electrical characteristics that upon the impedance of said coil being increased by the positioning of the movable armature within the path of magnetic flux of said coil the said circuit is placed in a condition of resonance with no eiective how of current sucient to energize the relay, and that upon the impedance of said coil being reduced by the withdrawal of the movable armature from the path of magnetic flux of the coll eectlve current flow is established in said circuit suiclent to energize said relay.

JACOB LEE TURNER.

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