US2671200A - Safety signal device - Google Patents

Description

March 2, 1954 J. F. LEDERER 2,671,200

SAFETY SIGNAL DEVICE Filed Oct. 18, 1950 2 Sheets-Sheet l INVENToR. Lwww 'Zzdzrer March 2, 1954 J. F.' LEDERER SAFETY SIGNAL DEVICE 2 Sheets-Sheet 2 Filed 061;. 18. 1950 INVENToR. femme Fler/ref Patented Mar. 2, 1954 UNITED STATES FFICE 6 Claims.

This invention relates to a safety signal device and particularly to a device for providing an immediate and accurate indication of the presence of metallic particles in a lubricant.

The presence of foreign substances, such as metallic particles and granular carbon in a continuous flow lubricating system is detrimental to the engine or machine in which the lubricant is being utilized. Granular carbon and particularly metallic particles are of an abrasive nature which results in a scoring of machine parts which are normally required to be held in extremely close tolerances. Thelscoring of machine parts and other damage resulting from the presence of abrasive metallic particles oftentimes results in a. substantial rise in operating temperatures, which, together with other resulting detrimental effects, may lead to rapid engine failures.

In engines generally, and particularly in those incorporating a continuously circulating` iubri cant, the presence of metallic abrasive material is highly undesirable and is normally difficult to detect before considerable damage or engine failure results therefrom. This is particularly true in aircraft engines where a departure from standard operating conditions or engine failure may lead to great loss of life and damage to property.

This invention may be briefly described as a device for detecting and providing an immediate indication cf the presence of metallic particles in a continuously flowing lubricant, of suflicient sensitivity to detect the presence of said particles before scoring and damage to close tolerance machine elements or engine failure results therefrom. The invention includes means for setting up an electric field of constant characteristics through which the lubricant is passed, with associated means responsive to a change in said constant electric field resulting from the presence of metallic particles therein, for providing an immediate indication of the presence of said particles.

In order to increase the response, to the indicating mechanism, of very small or relatively few particles in the oil stream l' prefer to include means for appropriately charging the particles in advance. n

An object of this invention is to provide a safety signal device for the detection of metallic parn ticles in a flowing lubricant.

Another object of this invention is to provide a simple and eiicient safety signal device for the detection of metallic particles in a fiowingV lubricant.

- Another object of this invention is to provide a simple and inexpensive device for providing a clear external indication when the presence of metallic abrasive material in a lubricating system reaches a predetermined amount.

Another object of the invention is to render metallic particles in a flowing lubricant more readily detectable.

A further object of this invention is to combine in a flowing stream or closed circuit of lubricating liquid means for charging the extraneous particles such as metallic particles and quantitatively detecting the presence of such particles to give warning in ample time to prevent engine failure.

Other objects and advantages of the invention Will be pointed out in the following disclosure and claims which disclose, by way of example, the principles of the invention and the preferred embodiments vof the safety device applying those principles.

Referring to the drawings:

Fig. 1 schematically illustrates the presently preferred embodiment of the invention;

Fig. 2 schematically illustrates an alternative embodiment of the invention;

Fig. 3 schematically illustrates another alternative embodiment of the invention;

Fig. 4 schematically illustrates another alternative embodiment of the invention which includes means for both charging the particles and activating the detection mechanism;

Fig. 5 is a slight modification of the condenser structure shown in Fig. 4, and

Fig. 6 is another schematic diagram illustrating means for charging the particles in a owing stream shown in conjunction with the detection method of Fig. l but which may also be used in conjunction with any of the alternatives shown in Figs. 2 to 5, inclusive.

Referring to Fig. 1, there is illustrated a portionlof the lubricant containing line lil formed of non-magnetic material through which the lubricant or a portion thereof continuously flows. Encircling the lubricant containing line lil is a helical coil I2 connected to a suitable direct current source, such Aas the battery l fi, in series with the primary winding lli of the transformer I8.

The direct current source le connected in circuit With'the coil l2 results in the formation of a magnetic eld of constant and uniform char-' acteristics within the lubricant flowing in the non-magnetic lubricant containing line it. The presence of particles of magnetic material, such as'small metallic particles, within the magnetic field vgenerated by the coil l2 results in a change winding lof the transformer i8 resultinglr from the presence'of metallic particles in the lubricant in the line it, results in a change in current flow in the secondary Winding 22 which is used to vary the frequency of the oscillator 24. @e .Output 0l the oscillator 24 is fed into two stages of conventional amplication 26 and 28 and the amplified output is fed into a discriminator. QQ. 'I lie die; criminator circuit 30 provides a varying voltage output which is responsive to the change in vfre"- quency of the oscillator 24. The varying voltage output of. the discriminatori 3Q is` used to actuate an attention arresting indicating device 32, which. may be'a suitable light, buzzer, or other signaling device, through, for. example, a suitable holding relay,- to provide a warning. signal ofpredc termined duration.

In the above embodiment of the invention the. circuitsfor the oscillator 24, the an'ipliiiers` 'it and 28, and the discriminator. 30, are of coni/ten tional and well-knownconstruction, and, as no claim of novelty is being directed to these circuits individually, they. are represented schernat` ically` in the drawings.

Fig. 2 illustrates an alternative embodiment of. the invention. Inthls embodiment, there is illustrated a portion of'the liilcrican't` 'containing line 40 formed ofnonemagnetic materiai through which the lubricant. or. a' portion thereof conv tinuously flows. Encircling. the lubricantl containing line 40 is a helical coil 42 connected to a suitable direct current source, such as the hattery. 44, in series' with"the"primary. winding 45 of a transformer 48.

A's. described above with respect to Fig. l, the direct current source 4.4 connected in circuit with the coil 42` results.' in a formation ot a magnetic field of constant and uniform characteristics within the'v lubricant owing in the` non-magnetic lubricant containing line' 4,0. The. presence of a particle of magnetic material, such as. small mel tallic particles, within the magnetic eld."gener. ated bythe coil 42. results' in the change in said magnetic field. The change in the'v magnetic eld results in a change in the current 'flowing through the circuit includ-ing the coil 42, the'A direct. current source 4&1 and the 46 of the transformer 48.

Connected in circuit. with thefsecondary winding 50 of the transformer 4iiar'e several stagesf of-` amplification 'such as tlie ampliers 52, 5t and 5,5. The change iniA current iiow. in theprimary winding 46 of.'v the transformer 487resultingff-roni the presence ofmetallic particles in the lubricant in the line 40 results in a change 'in current fiow' in thefsecondaryfwinding 5c. The change in curn rent iiow in the' secondary winding 5l]` is utilizedto vary the. grid voltage in the amplifier 52A.1 Said."

amplifier. 524 is biased so that, this change. in. grid voltageresults in a correspondingy ampliiied outl put. Theampliiied output. ofstage 52; is further.

primary winding current flow resulting from the presence of metallic particles in the line 40 and the output required to trigger the indicating device 58. The amplified output in the embodiment illustrated in the drawings of stage 56 is used to trigger an eye-arresting indicating device 58 which may be a suitable light, buzzer, or other signaling device, through, for example, a suitable holding relay to provide a signal of predetermined duration.

In` the embodiment of the invention illustrated in Fig. 2,'the circuits for the amplifiers 52, 54 and 56 are of conventional and well-known construction, and as no claim of novelty is being directedA toward these circuits individually, they are. represented schematically in the drawing.

Y'Fig'f illustrates another alternative embodiment ot the invention. In this embodiment of the invention, there is illustrated a portion of a lubricant containing line 62 through which the lubricant or a portion thereof continuously flows. Bounding the line 62 are a pair of condenser plates 64 and V615 positioned so that the lubricantl flowing in'the line 62y serves as a dielectric therefor..` The condenser plates `(i4 and Sii are included in the circuit of a oscillatorkv 68 normallyfbiased to provide a constant frequency output. The capacitancer of the condenser. formed by the plates 64 and 66- is a function ofl thedielectric material interposed therebetween, i. e. the lubricant flowing in the line 62; The presence of metallic 'particles in the lubricant fiowing'in the line E2 results. in a change in the dielectric constant of the material interposed between the plates 6d and 66. The change in the dielectric constant varies the capacityofthe condenser formed by. such plates 64 and 6G and this variation in. capacity. is usedr to vary. the frequency. ofthe oscillator '58.

As'describe'd above in connection with Eig` l,

`. the "output of the oscillator. 68 is fed into` two rectl-y` or. through a'n intermediate holding relay..

to provide a signal of predetermined duration In this embodiment of the invention, as in the embodiments illustrated in` Figs. 1 and 2fthe circuit arrangements of. the units. schematically. represented are conventional and of Well-known 1 construction.

Asillustrated in Fig. 4 a set of concentric cons denser `plates. Ilv of tubular. 'form are mountedl within' andfinsulated from a tube or 'pipe 18 through which'particles "to be detected'putesI The 'condenser plates.v mlayl be` arranged asr fiatparallel sheets le' as shown in Fig.' 5 and itl- 1eV plates are charged by a suitable source ofelectricity. marked 80- in Fig. 4 and 8i inFig. 5.

The presence of the 'particles in passingl `oetween theplates fl act to disturb thechfarge in the condenser and this disturbanceor variation in capacity is recorded. or signaled by suitable apparatus such as a voltmeter 32 asin Eig. 4 orasan ammetcr 83 as in Fig. 5'.:

The inner Wall of the tube' or. pipe| maybev insulated by anyfsuitable` coating or. lining 84, means. for.. amplifyingv the indicationf such as described in connection. with the` arrangement of:

Fig. lmay be employed.

The narticlesas. they. pass termali. the. Spaces between condenser plates will contact the plates and thus become charged which will magnify the effect as they continue to pass on.

6 illustrates an alternative embodiment of the invention. In this arrangement there illustrated portion ci a lubricant containing line or pipe 85 which is provided with an enlargement 35 having an insulating lining 8l and mounted within the enlargement is a charged body til having a corrugated or otherwise extended surface 39, the shape and size and mounting of the body being such as to provide adequate passage for the lubricant. The body S3 is charged by a suitable electrical source 99 so that the metallic or lilze particles in the stream will be charged they conta-ct the surface t9 of the body the charged particles continue through the line or pipe they influence the capacitance of a coneenser having plates 9i and 92 which bound the line and included in the circuit or" an oscillator 93, normally to provide a constant frequency output. capacitance or" the condenser formed by the plates 9| and 92 is a-iunction oi the dielectric material interposed therebetween, i. e. the lubricant flowing in the line. The presence of extraneous charged particles in the lubricant flowing in the line 35 results in a change in the dielectric constant and thus varies the capacity of the denser which in turn varies the frequency ci the oscillator 93.

The output of the oscillator 93 is fed into two stages of conventional amplifica-tions 9d and and the amplified output thereof is fed into a discriminator 93 which is used to actuate an sttention indicating device Si which may 'ee suitable light, buzzer or other signaling device.

This part of the embodiment of my invention corresponds to the arrangement already shown and described in connection with Fig. 3 and the alternative arrangements of Figs. 1 and 2 may be substituted therefore if desired.

The advantage gained by the complete embodiment of my invention shown in Fig. 6 arises from the fact that the particles in the lubrication stream are charged as they come in contact with the extended surface of the charged body 98 and hence are more readily detected as they pass between the condenser plates 9i and 92.

This application is a continuation-impart of my copending patent application Serial No. 159,303, filed May 1, 1959, for Safety Signal Device, which is now abandoned.

It is to be understood that the invention is not limited to the specic embodiments herein shown and described but may be carried out in other ways without departure from its spirit.

Having thus described my invention, I claim:

1. Apparatus for the detection of extraneous solid particles in a lubricant owing in a line comprising means within the line for contacting and charging the particles as they ilow therein, means associated with the line containing the flowing lubricant and spaced from said charging means for extending a constant electric iield thereacross, means responsive to a change in said electric neld resulting from the presence of the charged particles therein for effecting an electrical change and an indicating device responsive to said electrical change for providing an external indication of the change resulting from the presence of extraneous particles therein.

2. Apparatus for the detection of extraneous solid particles in a lubricant comprising means disposed Within the iiow of lubricant for electrically charging said extraneous particles, means associated with the owing lubricant and spaced from said charging means for providing an electric eld of constant characteristics through which the lubricant must pass, means responsive to changes in said electric field resulting from the presence of charged particles therein for effecting an electrical change of greater magnitude, and .an indicating device responsive to said electrical change of greater magnitude for providing an external indication of the presence of said extraneous particles in said lubricant.

3. Apparatus for detection of extraneous solid particles flowing in a line comprising an electrically charged body disposed within said owing lubricant for electrically charging said extraneous particles, a sensing device spaced from said charged body and positioned to provide a constant electric field through which the flowing lubricant and the charged particles therein must pass, means associated with said sensing device and responsive to changes in said electric iield resulting from the presence of the charged particles therein for effecting electrical changes of greater magnitude, and an indicating device responsive to said electrical changes of greater magnitude for providing an external indication of the presence of said extraneous particles in said lubricant.

4. A method for detecting the presence of extraneous solid particles in a lubricant comprising the steps of charging said particles in said lubricant and measuring a change in a constant electric eld through which said lubricant and said charged particles pass to detect the presence of said particles.

5. A method for detecting the presence of extraneous solid particles in a lubricant comprising the steps of charging said particles in said lubricant, passing said lubricant and said charged particles through an electric field of constant characteristics and measuring the change in said field resulting from the presence of said charged particles therein.

6. A method for detecting the presence of extraneous solid particles in a lubricant comprising the steps of charging a body disposed in the lubricant to place a charge on the extraneous particles therein, passing said lubricant and said charged particles through an electric field of constant characteristics and measuring the change in said eld resulting from the presence of said charged particles therein.

JEROME F. LEDERER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,070,556 Strong Aug. 19, 1913 1,808,709 Blake June 2, 1931 1,973,414 Miller Sept. 11, 1934 2,228,293 Wurzbach Jan. 14, 1941 2,349,992 Schrader May 30, 1944 2,387,496 Cornelius Oct. 23, 1945 2,455,543 Williams Dec. 7, 1948 2,491,445 Cunningham et al. Dec. 13, 1949 2,512,879 Roggensten June 27, 1950

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