US3553672A - Electrically-conductive particle detector - Google Patents

Abstract

A PARTICLE DETECTOR SYSTEM FOR USE IN DETECTING WEAR OF A PART CONSISTING OF ELECTRICALLY-CONDUCTIVE MATERIAL IN CONTACT WITH A FLUID IN A FLUID CIRCULATING SYSTEM, WHEREIN THERE IS PROVIDED A FIRST ELECTRICALLY-CONDUCTIVE ELEMENT AND A PLURALITY OF SECOND ELECTRICALLY-CONDUCTIVE ELEMENTS SPACED AND ELECTRICALLY INSULATED FROM EACH OTHER AND FROM THE FIRST ELEMENT TO FORM GAPS. PARTICLE COLLECTING SURFACES ARE PROVIDED IN THE GAPS, AND MEANS ARE PROVIDED FOR PROMOTING THE DEPOSITION OF THE PARTICLES BETWEEN THE ELECTRICALLY-CONDUCTIVE PART ON THE SURFACES TO FORM AN ACCUMULATED DEPOSIT OF ELECTRICALLY-CONDUCTIVE PARTICLES OR CHIPS IN THE GAP, WHEREBY THE DEPOSIT MAY INCRESSE TO THE EXTENT THAT THE GAP WILL BE BRIDGED BY THE DEPOSITS. IN ONE EMBODIMENT, THE MEANS INCLUDES A MAGNET EXPOSED AT THE SURFACE IN THE GAP. IN OTHER EMBODIMENTS, A WELL SUMP MAY BE PROVIDED FOR ENHANCING THE DEPOSITION OF CHIPS OR PARTICLES ON THE SURFACS INSTEAD OF THE MAGNET. FURTHER, A CYLINDERICAL SCREEN FILTER CAN BE PROVIDED BETWEEN THE INLET AND OUTLET OF THE OIL SUMP FOR ENHANCING THE DOPOSITION OF PARTICLES IN THE SURFACES OF THE GAPS. STILL FURTHER, THESE MEANS CAN COMPRISE BAFFLES CRITICALLY LOCATED FOR ENHANCING THE DEPOSITION OF THE PARTICLES FROM TYHE OIL ONTO THE DETECTOR. AN ELECTRICAL CIRCUIT IS PROVIDED FOR INDIVIDUALLY DETECTING THE BRIDGING OF PRESELECTED GAPS BY THE PARTICLES. A PLURALITY OF DETECTORS CAN BE USED IN A SYSTEM WHEREIN A MASTER DETECTOR IS LOCATED IN A COMMON FLUID DUCT, WHILE SUBSIDARY DETECTORS ARE LOCATED IN BRANCH DUCTS, WHEREBY THE MASTER DETECTOR CAN ACTIVATE THE DETECTORS IN THE BRANCH DUCTS, ONCE A PRESELECTED NUMBER OF GAPS IN THE MASTER DETECTOR HAVE BEEN BRIDGED.

Description

Jan. 5, 1971 I J. N, SMITH ELECTRICALLY'CONDUCTIVE PARTICLE DETECTOR 4 Sheets-Sheet 1 Filed June :5, 1968 INVENTOR John Norman SMITH A TTORNEY Jan. 1971 J. N. SMITH 3,553,672

ELECTR ICALLY CONDUCTIVE PARTICLE DETECTOR Filed June 5. 1968 4 Sheets- Sheet 2 FIG? INVENTOR John Norman SMITH A TTORNEY Jan. 5, 1971 J. N. SMITH BLECTRICALLY-CONDUCTIVE PARTICLE DETECTOR Filed June 3, 1968 4 Sheets-Sheet 3 ill]. ms-n b INVENTOR John Norman SMITH RYE Jan. 5, 1971 $M|TH 3,553,612

ELECTRICALLY-CONDUCTIVE PARTICLE DETECTOR Filed June 5, 1968 4 Sheets-Sheet 4 \\\O L I $52 22? 70 7 i ,7 802 MA! Dans-c7102 700 1 1 1 l 1: Fla ,8 Mfl/IV Amie) d/PCu/T Y My E REL/3y INVENTOR John Norman SMITH ATTORNEY United States Patent 3,553,672 ELECTRICALLY-CONDUCTIVE PARTICLE DETECTOR John N. Smith, 90 Sweetbriar Drive, Beaconsfield, Quebec, Canada Continuation-impart of application Ser. No. 604,880,

Dec. 27, 1966. This application June 3, 1968, Ser.

Int. Cl. G08b 21/00 US. Cl. 340-270 33 Claims ABSTRACT OF THE DISCLOSURE A particle detector system for use in detecting wear of a part consisting of electrically-conductive material in contact with a fluid in a fluid circulating system, wherein there is provided a first electrically-conductive element and a plurality of second electrically-conductive elements spaced and electrically insulated from each other and from the first element to form gaps. Particle collecting surfaces are provided in the gaps, and means are provided for promoting the deposition of the particles be tween the electrically-conductive part on the surfaces to form an accumulated deposit of electrically-conductive particles or chips in the gap, whereby the deposit may increase to the extent that the gap will be bridged by the deposits. In one embodiment, the means includes a magnet exposed at the surface in the gap. In other embodiments, a well sump may be provided for enhancing the deposition of chips or particles on the surfaces instead of the magnet. Further, a cylindrical screen filter can be provided between the inlet and outlet of the oil sump for enhancing the deposition of particles in the surfaces of the gaps. Still further, these means can comprise baffles critically located for enhancing the deposition of the particles from the oil onto the detector. An electrical circuit is provided for individually detecting the bridging of preselected gaps by the particles. A plurality of detectors can be used in a system wherein a master detector is located in a common fluid duct, while subsidiary detectors are located in branch ducts, whereby the master detector can activate the detectors in the branch ducts, once a preselected number of gaps in the master detector have been bridged.

This application is a continuation-in-part of application Ser. No. 604,800 filed Dec. 27, 1966, and now abandoned.

The present invention relates to a segmented wear detector for use in dynamic machinery employing fluid circulating ducts and to a method and system for detecting wear in such machinery employing such a wear detector. More particularly, the invention relates to a segmented wear detector which may be fitted, for example, within oil lubrication ducts or compartments and which will provide one or more electrical signals, indicative of unusual wear rate in one or more components of the moving parts, such as bearings, past which the oil flows, and which can be arranged to isolate and indicate, as required, the area of unusual wear rate.

It is known to insert within a lubrication duct or compartment, a permanent magnet adapted to attract particles, such as steel, dust or chips, the magnet being removable for visual inspection periodically. It is also known to provide such a magnet with a pair of contacts or electrically insulated elements which will close a single electric circuit when the contacts or elements are interconnected by metal particles which are attracted to the device. In such devices, however, the information provided is extremely rudimentary. Gradual wear normally takes place in most dynamic 3,553,672 Patented Jan. 5, 1971 of the type envisaged, and metal dust slivers will be liberated in the course of this wear and will, by attraction, close the electrical circuit, immediately producing a signal, giving what is in elfect a false alarm.

It is an object of the present invention to improve such a devlce in such a way as to render it capable of providing information as to the rate and quantity of Wear, so as to enable a rapid rate or quantity of wear from a worn surface to be distinguished from normal operation wear, while virtually removing the false alarm feature. Indication may be arranged to provide immediate, cumulative, automatic and/or command display, under surveillance or remote conditions, as desired.

Generally the invention comprises a wear detector for use in detecting wear in a part in contact with the fluid in a circulating system, a first electrically-conductive element, a plurality of second electrically-conductive elements spaced and electrically insulated from each other and spaced and electrically insulated from said first element to form gaps, chip-collecting surfaces in said gaps, means for promoting the deposition of chips on said surfaces; each of the second elements being connected through electrical circuitry with the first element whereby the circuits will be activated as the gap between each second element and the first element is conductively bridged by a deposit of chips.

An important aspect of the invention is the electric circuitry which can be so arranged that signal storage is provided. In other words, as individual gaps are bridged, the signal triggered is retained until a variably selected number of gaps are activated, at which time the indicators corresponding to the gaps bridged may be displayed. Successively thereafter, as the remaining gaps are bridged, the corresponding indicator is activated. Alternatively, the signal may be stored to an advice level of X number of gaps bridged, thereupon activating a first single caution warning; further bridging of all the remaining gaps may then activate a second single master warning. Additionally, a third single master alarm indication may be displayed by bridging a separated high level electrical circuit. The circuits may be used separately or in any variable combination and can be electrical, electronic, solid state, fluidic or any known equivalent.

In an embodiment of the invention, an isolation or collection well is provided in which the detector, as described above, can be incorporated. Such a construction would include a fluid inlet and a fluid outlet, a well chamber defined below the normal line of flow between the fluid inlet and said fluid outlet whereby the fluid would be caused to swirl in a vortex or generally swirl around as in a sump, allowing any solid particles in the fluid to centrifuge to the outer wall of the chamber, and then to deposit at the lower end of the well. A segmented detector is located at the lower end of the well adapted to detect the rate or quantity at which the solid electrically-conductive particles precipitate from the fluid in the well.

In accordance with one embodiment of the invention, there is provided a segmented wear detector for use in dynamic machinery employing fluid circulating ducts or compartments, the detector includes a magnet body, a first element electrically-conductive material positioned adjacent a surface of the body. A plurality of second elements of electrically-conductive material are positioned adjacent the surface of the body, with the second elements being electrically insulated one from another and from the first element. The first and second elements are aligned to define therebetween a narrow elongate spacing gap through which the surface of the body of magnetic material is provided so as to cause the gap to be magnetically attractive to particles of ferro-magnetic material.

In accordance with a further aspect of the invention, the segmented wear detector as described above can be constructed with the use of a non-magnetic body. In this case, the interior well surfaces of the collection well are such as to enhance the deposition of the electrically-conductive particles to gravitate towards the detector which would normally be at the lowest point of the well. In this case, gravitational deposition and the specially designed inner surfaces of the well would be sufficient to direct the particles to the gaps rather than the magnet as in the previous embodiment.

In accordance with still another aspect of the invention, there is provided a method of detecting wear in dynamic machinery employing fluid circulating means such as conduits, ducts or compartment.

The method includes inserting within such circulating means one of the wear detectors as defined above and connecting the elements in an electric circuit arranged to energize an alarm when electric contact has been established between the first element and a selected number of the second elements by particles of electrically-conduc tive material carried by the fluid circulating in the duct.

According to yet a further aspect of the invention, there is provided a system for detecting wear in the dynamic machinery employing fluid circulating ducts or compartments comprising a wear detector as defined above located in a duct, with means interconnecting the elements in an electric circuit containing an electrically energized alarm and power supply means. The circuit is arranged to respond when contact has been established between the first element and a selected number of said second elements. The contacts defined respectively by the first element on the one part and each of the second elements on the other part is arranged in series, the circuit being closed when a selected number of said contacts has been bridged. For example, warning circuit closure may be arranged to occur after the third contact is bridged, in a unit employing ten contacts; thereafter, as each of the remaining contacts is bridged, the appropriate contact warning signal is activated.

The invention may be employed in a wide diversity of dynamic machinery, for example, gas or steam turbine lubricating systems, or lubrication systems of internal combustion engines, hydraulic systems of many kinds, for example, hydraulic systems on aircraft; free or enclosed fluid circulatory systems such as coolant systems, and also, for example, chemical or refrigerant circulating systems.

Insertion of the wear detector of the invention within such a fluid duct will provide a multi-signal or cumulatively delayed single signal alarm, distinguishable from accidental alarms which would be given by a single pair of contacts alone and providing immediate signal, which might be due to an isolated chip of electrically-conductive material freed into the circuit. The segmented contact circuits of the wear detector of the invention may be used to energize many types of alarms or indicator mechanisms. For example, a visual indicator consisting of a panel of bulbs, the number of which is consistent with the number of segments employed, may be provided so that each contact lights a bulb and a different type of bulb, possibly remotely located from the others, is lit responsive to the closing of all the contacts or a selected number of the contacts. Means may be provided for storing the individual panel light signals, viewable on demand by a test switch or panel, while still retaining an automatic single master caution and/or a further master alarm signal feature: used in any combination. Registration of the time of each circuit closure, to give an indication of the rate at which the contacts become closed, is available.

Having thus generally described the invention, it is hereafter more particularly described with reference to preferred embodiments shown and illustrated in the accompanying drawings, in which:

FIG. 1 is a typical plan view of the exposed surface of a Wear detector suitable for mounting in a suitable 4 adapter forming a section of a fluid conduit, or compartment;

FIG. 2 is an exploded perspective view of the wear detector of FIG. 1;

FIG. 3 is a section along the line 3--3 of FIG. 1;

FIG. 4 is a simple electric alarm circuit operable by the wear detector of FIG. 1;

FIG. 5 is a plan view of the exposed surface of a second form of wear detector in accordance with the invention;

FIG. 6 is a section along the line 6-6 of FIG. 5;

FIG. 7 is a modification of FIG. 3 showing the installation of an electro-magnet;

FIG. 8 shows a modification of the embodiment of FIG. 5 fitted with an electro-magnet;

FIG. 9 is a longitudinal sectional view taken from one embodiment of the detector in combination with a collection well, with a screen filter therein;

FIG. 10 is a top plan view, partly in cross section of the embodiment shown in FIG. 9;

FIG. 11 is an enlarged longitudinal sectional view, typical of the detector shown in FIG. 9;

FIG. 12 is an enlarged top plan view of the detector shown in FIG. 11, partly in cross section;

FIG. 13 is a fragmentary, longitudinal sectional view of another embodiment of a detail shown in FIG. 11;

FIG. 14 is a fragmentary, longitudinal cross section of still a further embodiment of a detail of FIG. 11;

FIG. 15 is a longitudinal sectional view of another embodiment of the detector collecting well in combination with the detector as shown in FIG. 11;

FIG. 16 is yet another embodiment of the combination of the detector and the well arrangement;

FIG. 17 is a top plan view partly in cross section showing the details of a by-pass arrangement for the fluid which can be provided with the chip-collecting embodiments shown in FIGS. 9 and 10;

FIG. 18 is a schematic diagram of one embodiment of the delay circuit;

FIG. 19 is a further embodiment of an indicating circuit which can be used with the detector shown in FIGS. 3, 5 and 9 through 16; and

FIG. 20 is a block diagram of an embodiment of the invention which utilizes a plurality of detectors positioned in various ducts of a machine.

Referring to FIGS. 1 to 3, there is shown a housing 10 of non-magnetic but electrically-conductive material (aluminum or stainless steel), of generally cylindrical configuration and having a central annular flange 11 from which projects an externally threaded stub 12 adapted to be inserted in a suitably shaped section of a conduit or into an adapter that forms an integral part of such a conduit or compartment, to be fastened in place by threading stub 12 into a machined threaded opening in the conduit section or compartment, thereby providing a fluid seal by tightening flange 11a, with gasket, to the proper surface of the compartment. An external socket portion 13 extends from the flange oppositely to the stub 12.

A recess 14 is bored in the end face of the stub 12 and a corresponding recess 15 (FIG. 3) is bored into the recess in the socket portion 13, the recesses being divided centrally by a base or web portion 16. Seated within the cavity 14 is a cup of insulating material 17, made for example of synthetic resin material. The interior surface of the cup 17 is moulded with four recesses 18, arranged sector-wise and divided by ridge portions 19. Seated within each of the recessed portions 18 is one of four elements 20 of L-shaped cross section and generally sector-shaped in plan. The elements are made of electrically-conductive and magnetizable material, for example, iron or steel. The elements are adapted to lie flush within the recesses 18 so that when seated in the cup 17, the surfaces of the ridges 19 and the interior surfaces of the elements form a smooth continuous cup-shaped surface.

Seated within this cup-shaped surface is a permanent magnet 21 which is electrically non-conductive.

The magnet is of annular configuration, that is, it is a shallow cylinder having a central axial bore, and it is of a size to fit snugly within the interior surface formed by the flanges 19 and elements 20. The elements 20 have generally sector-shaped base portions 22 which are truncated at the axis of the device to conform with the bore in the magnet. The upstanding walls 23 of the elements surround the magnet peripherally, and their upper ends or extremities 24 (FIG. 3) constitute a plurality of secondary magnet poles, standing slightly proud of the magnet surface.

The primary magnet pole or element is a centrally bored circular disc 25 of electrically-conductive and magnetizable material which overlies the magnet and is held in place by a central bolt 26 which passes through the central bores in the disc 25, magnet 21, elements 20 and cupshaped insulator 17, and which threadably engages a central threaded axial bore 27 in the web 16 of the housing. A lock nut (not shown) may be fitted to the end of the bolt 26, if desired. Between the disc 25 and the magnet 21 there is disposed a collar 28 of compressible thermoplastics material, which acts as a fluid seal and which is seated in a recess 29 in the upper surface of the magnet 21. A second seal 28a is provided at the lower end of the bolt 26.

It will be apparent that the disc 25 which forms the primary element is grounded through the housing to the conduit to which the wear detector is connected. The conduit is grounded to the main body of the machine involved, thus joining the common ground.

Each element 20 has joined to its base portion 22 so as to protrude downwardly therefrom, an electrode 30. The electrodes are shown connected by riveted joints, but they may be, for example, threadedly joined or welded to the base portions 22. The electrodes pass through bores appropriately situated in the base of the insulator cup 17 and the web 16 and are insulated and sealed from the housing 10 by sleeves 31 of insulating sealing material, for example, rubber compound or thermoplastic material.

Thus, the gap G between the primary element 25 and the segmented elements 20 determines the sensitivity of the detector. It will be apparent that this gap can be increased or decreased by replacing the disc or primary element 25 with discs of larger or smaller diameter as indicated by the dotted lines in FIG. 3. The attraction of a chip of magnetically attracted material to bridge the gap G will complete an electric circuit between the individual element 20 which is connected to electrode 30, and the central or primary element 25 which is grounded.

A suitable position for the insertion of a wear detector is, for example, at the outer side of a bend in a pipe or duct, where the fluid current will centrifugally, preferentially carry the majority of entrained particles into contact with the wear detector which should be facing radially inwardly towards the axis of the bend.

FIG. 4 shows a simple circuit into which the wear detector of FIGS. 1 to 3 may be connected. As shown, the primary element 25 is grounded, and the secondary segmented elements 24 are individually connected respectively in series both with a peripheral panel bulb 51 and a relay 52. A current amplifier may be inserted between each segment 24 and bulb 51, dependent on the insulating qualities of the fluids. Closing of the gap G between the primary element 25 and any one of the elements 24 therefore closes the individual relay 52 and also lights one of the peripheral panel bulbs 51 The contacts 53 of the relays 52 are connected in series between the live lead 50 and a central or alarm panel bulb 54, the other terminal of which is grounded. Therefore, when the contacts between the central element 25 and all the secondary elements 24 are made, all the relays 52 are energized and closed and the alarm bulb 54 lights. It will be apparent that the alarm bulb 54 may be replaced by some Cit other type of alarm such as a bell or recorded signal or may be used to provide a signal to bring the machinery to a halt or to perform some other similar function. Similarly, certain of the relay contacts 53 may be optionally short-circuited so that the alarm will be given when fewer than the total number of wear detector contacts are closed.

It may be of advantage to register the rate or quantity at which the pluraliy of contacts are successively completed, or alternatively, the time elapsed between the closure of the first contact and completion of all the contacts, to give an indication of the rate or quantity of wear of the machinery, so as to distinguish a sharp deterioration from slow accumulated deterioration which may take place in normal operational use. As an example, a recording tape may be started at the time of closure of the first segment circuit of a clean wear detector and the closing of each individual contact may be recorded successively on the tape. The tape may be examined periodically, or alternatively, the tape may be permanently connected with a computing device if the rate of completion of the successive contacts is faster than would be expected from normal operation of the machinery. More simply, each of the bulbs 51 of the circuit of FIG. 4 may be connected in parallel to a timing mechanism, started at the time of circuit closure of the first segment of a fresh wear detector, completion of the individual contacts being arranged to indicate the time at which each contact was made.

FIGS. 5 and 6 illustrate a second form of wear detector. As indicated in FIG. 5, the body of magnetic material which constitutes a magnet is in the form of a rectangular prismatic strip 121. The primary element takes the form of a sheet or foil of magnetizable and electricallyconductive material which is wrapped around a part of the magnet 121 so as to cover the base and extend over a small area of the upper exposed surface, as a thin strip 200 which terminates in an edge 201 which forms a straight line running the length of the magnet parallel to one of the sides. The secondary segmented elements 122 take the form of small rectangular sheets of the same magnetizable, electrically-conductive material which are adhered to the top face of the magnet, side by side, spaced and insulated one from the'other, and having forward edges 202 aligned and spaced equally from the edge 201 to leave a uniform straight line gap G. The magnet may be of non-conductive magnetic material as the magnet 21 of FIGS. 1 to 3, or may be a bar magnet enclosed by a thin jacket of insulating material, such as ceramics, to render the surface non-conductive. The elements may be simply adhered by a suitable adhesive, such as an epoxy resin material, to the surface of the magnet. Terminals 203 may be soldered to each of the secondary elements and a similar terminal 204 to the primary element. In this way, a great many more secondary elements may be used. It is contemplated that the device in this form will be inserted so that its length runs from transversely across the whole width of a conduit or an adapter, which may be suitably shaped to advantageously manipulate fluid flow velocity and use guide channels matching the plurality of segments, to ensure even distribution of wear particles to each segment.

FIG. 7 illustrates a variant of FIG. 3 in which a body of electrically-magnetizable material is used in place of the non-conductive permanent magnet 21. In the example shown, the body of electrically-magnetizable material takes the form of a cylinder of ferrite 300 around which is wrapped an insulated coil winding 301, the ends of which pass to connective pins 302 which pass through the web 16 from which they are insulated by further sleeves 303 similar to the sleeves 31. The electro-magnet and coil are insulated from the housing by a body 304 of insulating material, for example, molded plastics material. A disc of insulating material 305 covers the top of the coil to provide insulation at the gap G, The disc 25 makes contact with the top face of the electro-magnet.

FIG. 8 is a variant of the embodiment of FIGS. 5 and 6 employing a body of electrically-magnetizable material in place of the permanent magnet 121. In this case, the magnetizable body 121 is composed, for example, of ferrite. The contacts are electrically insulated from the body by the epoxy resin layer 401 by which they are adhered thereto. The ends of the body contact the ends of a horseshoe electromagnet 400.

However, the primary element 125 is not required in the embodiment shown in FIG. 8, since the lines of flux in the electro-magnet run longitudinally of the body 121. Rather the individual elements receive induced polarity longitudinally and the gap G is therefore between the individual elements 122.

It will be apparent that the device can take many other forms. For example, the device of FIGS. and 6 instead of running in a straight line across the pipe, could be curved in the form of a loop to surround the pipe or conduit with the surface containing the gap G facing radially inwardly towards the axis of the conduit. In this design, an electro-magnetic coil would be used preferentially due to the impracticability of making such a section removable for viewing. Furthermore, the secondary elements may be segmented in other ways, for example, in the form of a rectangular lattice configuration or in the form of two or more rows similar to the row of FIGS. 5 and 6, the primary element also being segmented, if desired. The number of secondary elements may vary considerably as required in the particular application.

A plurality of segmented wear detectors may be distributed with a large piece of machinery as required by the complexity of the machinery and the arrangement of the fluid flow circuit. An advantageous arrangement, illustrated in FIG. 20, may be used when there are a plurality of conduits 800 which flow from separate dynamic areas into a main junction conduit 801. A complex element illustrated generally at 802 and having, for example, 5 to 20 segments, may be situated in the common fluid junction conduit 801. Less complex wear detectors illustrated generally by the numerals 803 and having, for example, 3 to 5 segments, are situated appropriately in the branch conduits 800. If progressing wear is detected by the junction conduit or compartment 801, the location of the wear may be obtained by manually or automatically switching in, successively or accumulatively, the secondary wear detectors 803 in the branch conduits 800 which will indicate in which part of the circuit the wear is present.

Where the cost of the machinery justifies the expense, both the primary and secondary wear detectors 803 may be arranged to have information fed to a computer so that the presence and the situation of the wear will be immediately signalled.

It can be of advantage to employ electro-magnetically energized wear detectors in the branch conduits 800. In such a case, the branch detectors 803 may be left dormant until unusual wear is detected to a predetermined level by the main wear detector 802. The branch detectors 803 may then be energized automatically by the alarm signal of the main wear detector 802. For example, the main alarm circuit 804 of the main wear detector 802 may have in series with it a relay 805 adapted to energize the branch wear detectors 803. The branch detector 803 involved will then begin to accumulate the unusual ferromagnetic wear, signalling as each gap is bridged or storing the signal until all gaps are bridged. Optionally, when the involved branch detector has signalled the location of the origin of unusual wear, as provided above, the circuit energizing the electro-magnets (not illustrated) of all the branch detectors 803 can then be canceled, permitting the main or common detector 802 to continue to detect the entire unusual wear rate. The material collected by the electro-magnet detector will thus have been released to now accumulate on the main or common detector. If it is required to measure the rate or quantity of all electricallyconductive wear, then a wear detector incorporating a non-magnetic body is used as will be described later.

It will be apparent that many modifications may be 8 made in the wear detector and circuit arrangements described, within the scope of the invention. As examples, it may be stated that it is not necessary to use a magnet of non-conductive material. The magnet may be suitably insulated by a thin surrounding jacket or the elements individually insulated. Furthermore, it is not necessary to use a single piece of material as the magnet. Magnetic dust may be suitably housed within a surrounding jacket of the required configuration, or a number of individual magnets may be arranged to constitute the body of mag netic material in accordance with the invention. If suflicient attraction is present from the magnet by exposure of the gap G between the contacts, the elements 20 or 122 and 25 or 125 need not be themselves rendered magnetically attractive, but may be merely of non-magnetic electrically-conductive material, such as copper. However, in such a case, it will be necessary to use stronger magnets. In all cases described, electro-magnets may be applied rather than permanent magnets. In the examples shown, it will be apparent that the circuit between one of the secondary elements and the primary element may be made by a chip of material which overlaps two secondary elements and only one of which overlaps between the primary and secondary elements. If desired, the secondary elements may be spaced by ridges of insulating material to prevent contact being made between them so as to restrict the contact entirely between the primary element and each respective secondary element. This is not, however, necessary in all applications.

Referring particularly to FIG. 9, a typical chip-collecting apparatus is shown which can be connected in a delivery or scavenge fluid circulation system for a dynamic machine such as a lubrication system for a turbine engine. The unit shown in FIG. 9 can be connected to a common conduit of lubricating oil or one coming from a bearing or other critical member area which is lubricated by the oil; the upstream side of the conduit would be connected to the inlet 500 of the chip-collecting unit. The other portion of the conduit is connected to the fluid outlet 502. In this particular embodiment, a cylindrical filter is provided between the fluid inlet 500 and fluid outlet 502. In the present case, the cylindrical screen 504 is peripheral about the opening 503 to the fluid outlet 502. The chipcollecting unit further comprises a wall 506 on which is mounted an annular filter support 507 which is in turn connected to the filter 504, The wall 506 converges downwardly to form a plenum area 508. Finally, at the apex of the plenum 50-8, the wall defines a quiet zone 510. To the bottom end of the quiet zone 510 is mounted a detector 511, of any of the configurations claimed, which is typically attached to the end of the wall 506 by screws 520, shown in the drawing.

Wall 506 can easily be disconnected from the upper portion of the detector unit by means of disconnect joint 512. In this case, when the wall 506 is connected to the upper part of the chip-collecting unit, a safety lock pin 514 is provided to prevent the bottom portion of the chipcollecting unit from disconnecting.

At the bottom of the filter 504 is provided an optional by-pass pressure differential relief valve 516.

Referring more particularly to FIG. 10, it is noted that the fluid inlet 500 is located at an angle to the well or sump defined by the wall 506. This is to provide a swirl or a vortex motion to the fluid as it is entering the collecting unit.

Another embodiment of the detector 511 is shown in FIG. 11. This is a non-magnetic detector and includes a body 522 which is of electrically-conductive material. The detector 511 relies on a chip-collecting environment as shown in FIG. 9 and gravity to deposit the metallic chips on the surface of body 522 rather than by magnetic attraction as shown in the previous embodiments. An annular seal 523 is provided throughout the body 522 for the sealing contact against the walls 506 of the chip-collecting unit.

Also, an annular flange 524 is provided at the lower portion of the body 522 and is provided for mounting the detector 511 to the wall 506 of the collecting unit.

Extending downwardly from the flange S24 is a cylindrical wall portion 526 which is threaded on the outside and is open on the inside.

An annular insulating member 528 is provided about the top of the body 522 and includes downwardly converging wall surfaces 530. This insulating member 52 8 provides insulation between the wall 506 of the collecting unit and the upper surface of the body 522. With a converging surface 530, the insulation member 528 also enables the particles or chips which were falling in the quiet Zone 510 to be more easily located on the electrode portion of the top portion of the body 522, while additionally protecting contact 532 from transient or premature closure. On the inner surface of the annular insulating member 528 is an annular electrically-conductive ring element 532 which may include inwardly extending prongs 533, dependent on environment requirements. This ring 532 is connected by an insulated lead 534 to a central electrically-conductive pin 5.36 which is insulated to the insulating body 522 by an insulating sleeve 542. The top portion of the electrical pin 536 is insulated from the top surface of the body 522 by means of an insulated conical cap 538. This detector configuration need not employ insulation 52 8 or secondary circuit contact ring 532, in which case, body 522 would extend upward from its peripheral top surface at an angle of from 60. Then pin 536 may become a 7th contact or be used as a ground.

Spaced about the central pin 536 and extending axially through the body 522 are a plurality of spaced electrical contact pins 540. In the present case, as shown in FIG. 12, there are six electrical contact pins 540 about the central pin 536. Each of the pins is insulated from the body 522 by an insulation sleeve 542. The top end portion of the pins 540 are exposed to the top surface of the body 522 as are the insulation sleeves 542, as can be best seen in FIG. 13.

The bottom surface of the body 522 is sealed by a potting 544 which can be made of ceramic or other similar materials. Through the potting 544 extend connector extensions 54-6 of the pins 540 and 536. These connector extensions are prong connections where it is required to lead individual circuits to the logic delay circuitry or to connect an indicating panel electrically to the contact pins 540 and the central pin 536.

FIG. 13 shows an enlarged view of the area about the contact pin 540 which is well illustrated. Since the top edges of the pin 540 are sloped at 552, the top surfaces of the insulating sleeve 542 surrounding the pin 540 is a V-cut groove corresponding with the slope 542 of the pin. The body surrounding the insulating sleeve 542 has also a sloping surface 550. The sloping surfaces forming a V-shaped groove about the pin 540 is provided especially to ensure that the metallic chips will always locate within the groove even though there may be slight vibrations in the detector caused by the machine in which it is installed. Of course, once enough chips have been collected within the gap 548 provided by the insulating sleeve 542, an electrical contact will be formed between the pin 540 and the electrically-conductive body 522.

A second high level electric circuit will also be completed as the metallic chips are built up on the upper surface of the body 522 to the prongs 533 of the annular conducting ring 532. When the chips are built up to this extent, an electrical circuit is completed between the body 522 and the ring 532 through the lead 534 to the central pin 5.36, providing an immediate signal.

It is noted that the body 522 of the embodiment described, FIGS. 11 to 13, is not magnetic or electromagnetic. The means for collecting the chips with the gaps 548 is provided by gravity and by the sloping surfaces which prevent the chips from being shelved in their descent to the detector in which ultimately the chips are forced to be directed to the insulated gaps 548.

It is also proposed to extend the pins 540 above the surface of bod-y 522 and the insulation sleeve 542 to the level of the body 522, rather than having it recessed as in the above described embodiment.

A magnetic disc insert (not shown) may be fitted to the top face of body 522, retained by epoxy or the inwardly extending shoulders of insulator 528. Such magnet would conform to all surface configuration requirements as described for body 522. Such magnet, of course, must be of electrically conductive material.

FIG. 14 is a fragmentary view of the central pin 536 showing another embodiment thereof of a second high level electrical contact. In this case, taken in connection with FIG. 13, the pin 536 is exposed to the surface which provides a further exposed contact element 554 and can be electrically connected to the body 522 as chips build up to the level of the element 554. It is noted in this embodiment, that the element 554 may be sharp edged, the surfaces including small, acute angles to the horizontal. This configuration is provided to overcome the discrepancies which may occur by the vibration in the machinery to form false gaps between the chips and the contact element 554, and is complementary to the prongs 533 on annular ring 532 (FIG. 13).

FIGS. 15 and 16 show different embodiments of the chip-collecting unit which do not include a filter screen as shown in the previous embodiment in FIG. 9. In FIG. 15, the fluid inlet is indicated at 600 while the fluid outlet is shown at 602. The wall 606 is in the form of a downwardly extending cone and defines a quiet zone 610 at the bottom thereof where a detector 611, of any of the configurations claimed, is connected. A disconnect joint 6-12 is similar to the disconnect joint 512 in the previous embodiment. It is also included in this chip-collecting unit.

In this embodiment, the baflie 619 is located in the normal flow path of the lubricating fluid which causes the fluid to deflect downwardly into the plenum defined by the wall 606. A coarse spiral thread 615 is provided throughout the plenum and as the fluid enters at a tangent as shown in the embodiment of FIG. 10, the fluid is forced further downwardly by this spiral thread further encouraged to engage the spiral thread 615, by baflie 617. Of course, as the fluid is conducted about the spiral downwardly in a swirl, the chips are caused to deposit on the top surface of the detector 611.

FIG. 16 shows another embodiment of the chip-collecting unit where no filter is provided. In this case, the plenum shown at 708 is defined by the walls 706. Of course, the stepped configuration shown will cause the lubricating fluid entering at inlet 700 to decelerate and to deflect in the plenum and the chips deposit on the detector 711. Of course, the lubricating oil is then discharged through the outlet 702. Preferentially, permanent magnet or electromagnetic detectors are used in this embodiment.

Shown in the top plan view of FIG. 17 is a chip-col lecting unit embodiment for use in a scavenge system conduit, having an inlet 500 and an outlet 502 and which is illustrated in FIGS. 9 and 10, and is there shown in combination with a by-pass conduit 560. A by-pass control valve 562 is shown connected to the inlet 500 and includes a pivoting valve gate 564 which can be selectively located on the valve seat 566 or alternatively the valve seat 568. A linkage arrangement is represented at 570 which is used to operate the valve gate 564. In this arrangement the valve gate could be normally in its position against the valve seat 566, therefore causing the lubricating fluid to by-pass the chip-collecting unit, by-passing through the by-pass conduit 560. However, if at any period it is required to determine the rate of wear of parts from which the lubricating fluid is being delivered, then the linkage 570 can be remotely operated to operate the gate 564 to its position 568, closing the by-pass conduit 560. Thus, the fluid will be required to pass through the chip-collecting unit.

Referring to the circuit in FIG. 18, which shows one embodiment of a simple electrical detecting circuit which can be used with any of the chip detectors described in the present application. In this circuit, six contact elements 540 (FIG. 11) are used defining six gaps identified as 700 with the body which is an electrically-conductive body 522 and which is grounded. The electric conductive contact elements 540 are connected to resistors identified at 702 in FIG. 18 and in turn to a relay 704 which is normally open. A Variable resistor 706 can be provided between the relay 704 and the contact elements 540. The variable resistor 706 can be set to close the normally open switch or relay 704 at any predetermined level of resistance depreciation through resistors 702, as circuits 700 progressively bridge. In the present embodiment the relay 704 has been set to be closed when the six gaps 700 have been closed. This closes the circuit to warning light 710, and an alarm is indicated.

When it is required to test the detector system, the press button 708, normally open, is depressed to close the circuit. This simulates closure of all six of gaps 700, and confirms relay and indicator light function.

For spot checks, a maintenance inspection circuit panel 712 can be connected quickly to connector extensions 546 of the contact pins 540, as described for FIG. 11. The panel 712 has a light indicator 714 for each contact pin 540. Therefore, the gaps 700, any number of which may be closed at any time, will be indicated on the corresponding lights 714 on the panel 712.

In the circuit shown in FIG. 19, the arrangement of the gaps 700 and resistors 702 in line with the relay 704 is the same as FIG. 18. A second relay 718 which is shown as having a double pole arrangement is also connected to the common circuit after coming through resistors 702 from each contact element 540. In this case, as a certain number of the gaps 700 are closed, the first relay 704 will determined by its operating resistance value, close its switch allowing the current to light the first warning light 720. However, when the remainder of the gaps are closed, then the second relay 718, again determined by its resistance value, closes its double poles. One of these poles allows current to go to the second warning light 722, activating it. The circuit to gap 701 shown would now be armed by the remaining relay pole, for completion of its circuit by bridging gap 701. This circuit, referred to as the high level warning would be activated when the chips have built up to the height of contact element 554, and the alarm indicated at 724 would immediately be lit. Relay 704 and indicating light 720 are optional in this embodiment. Press to test 708 would function as described for FIG. 18,- by simulation, activating both relays, illuminating all indicating lights.

Similarly, a maintenance inspection plug in electrical panel applies, as detailed for FIG. 18.

It is also contemplated to substitute the above described circuit by a solid state circuit as is well known in the art.

I claim:

1. A particle detector for use in detecting wear in a part consisting of electrically-conductive material in contact with a fluid in a fluid circulating system, a first electrically-conductive element, a plurality of second electrically-conductive elements, spaced and electrically insulated from each other and spaced and electrically insulated from said first element to form gaps, particle-collecting surfaces in said gaps, means for promoting the deposition of particles worn away from said electrically-conductive part on said surfaces to form an accumulated deposit of electrically-conductive particles on said surface in the gap whereby such deposit may increase to the extent that said gap will be bridged by said deposit; each of the second elements being connected through electrical circuitry with the first element whereby the circuits will be activated as the gap between each second element and the first 12 element is conductively bridged by the deposit of particles on the surface.

2. A wear detector as defined in claim 37 wherein the means for promoting the deposition of particles on the surfaces is a magnet body.

3. A wear detector as defined in claim 2 wherein the magnet body includes an exposed surface in said gaps and said first and second elements electrically-conductive being positioned adjacent the exposed surface of said magnet body whereby said exposed surface is the particlecollecting surface.

4. A wear detector as claimed in claim 3 wherein the magnet is a shallow cylinder having an axial bore, said first element comprising a substantially circular disc centrally disposed against one end face of the magnet, the said second elements each having a circular sector shape being arranged around the periphery of the magnet, the gap being defined between themselves and the central first element, the latter being mounted and electrically connected through said central bore in the magnet.

'5. A wear detector as claimed in claim 4 wherein the said second elements are of L-section having upstanding peripheral walls which are curved to conform with the outside cylindrical surface of said magnet and the ends of which constitute the ends of the elements and base portions of generally sector shape underlying the magnet.

6. A wear detector as claimed in claim 1 wherein the number of said second elements is variable between 3 and about 20.

7. A system for detecting wear in dynamic machinery as defined in claim 1 employing fluid circulating ducts comprising:

a wear detector located in a said duct, conduit or compartrnent;

electrodes connected to each respective element;

means interconnecting the said electrodes in an electric circuit containing an electrically-energized alarm and power supply means, the circuit being arranged to respond when contact has been established between said first element and a selected number of said second elements, the contacts defined respectively by the first element on the one part and each of the second elements on the other part being arranged in series, the circuit being closed when a selected number of said contacts has been closed.

8. A system as claimed in claim 7 wherein the housing means is arranged to so manipulate velocity and dispersal of fluid flow such as to enhance concentration and attraction of particles to the segments and to average the total flow past each segment.

9. A system as claimed in claim 8, wherein the unit is easily removable or openable for visual inspections and cleaning or renewing of the detector body.

10. A wear detector as defined in claim 1, wherein the means for promoting the deposition of chips on said surfaces includes a well housing defining a chamber, said well housing having an inlet opening and an outlet opening communicating with the fluid flow, and said particlecollecting surface is spaced below said inlet and outlet openings.

11. A wear detector as defined in claim 10, wherein a fluid filter is provided between the inlet and outlet, and said chip-collecting surface is spaced below said filter.

12. A wear detector as defined in claim 10, wherein the chamber is defined partly by sloping walls converging from the inlet and outlet area to said chip-collecting surface, whereby the chips gravitating from the fluid flow are directed on to the chip-collecting surface.

13. A wear particle detector as claimed in claim 1 wherein at least two of said electrical circuits are coupled to a first stage signal means for generating a signal once said at least two of the said electrical circuits are both activated by the deposit of particles on the surface in each respective gap associated with the at least two said electrical circuits.

14. A wear particle detector as claimed in claim 13 including a second stage signal means having an input coupled to a higher number of said electrical circuits than said at least two of the said electrical circuits for generating a second signal once said higher number of said electrical circiuts are all activated by the deposit of particles on the surface in each respective gap associated with the said higher number of said electrical circuits.

15. A wear particle detector as claimed in claim 14 including at least one additional stage signal means having an input coupled to still a higher number of said electrical circuits than the first said higher number for generating at least one additional signal once said still higher number of said electrical circuits are all activated by the deposit of particles on the surface in each respective gap associated with the said still higher number of said electrical circuits.

16. A segmented wear detector for use in dynamic machinery employing fluid circulating ducts or compartments comprising:

a magnet body;

a first element of electrically-conductive material posi tioned adjacent an exposed surface of said magnet body; a plurality of second elements of electricallyconductive material positioned adjacent said surface of the body, the second elements being electrically insulated one from another and from the first element;

the first and second elements being arranged to define therebetween gaps through which the magnet body is exposed so as to cause said gap to be magnetically attractive to particles of ferro-magnetic material;

first electrical connecting means connected to said first element; 1

a plurality of second electrical connecting means connected electrically one to each of said second elements;

housing means mounting said body, elements and electrical connecting means in a unit, and adapted for mounting said unit for operation within a fluid circulation duct or compartment with said surface eX- posed to fluid circulating in said duct or compartment.

17. A segmented wear detector as defined in claim 16 wherein the magnet body is of permanently ferro-magnetic material.

18. A segmented wear detector as defined in claim 16 wherein the magnet body is of electrically-magnetizable construction and electrical means are provided for supplying electric current to said material.

19. A segmented wear detector for use in dynamic machinery as defined in claim 16, wherein the first elements are of magnetizable and electrically-conductive material bearing against one surface of said body;

the plurality of second elements are magnetizable and electrically-conductive material bearing against a second surface of said body;

the first and second elements having surface portions aligned along a common geometric surface and defining therebetween a narrow elongate spacing gap, said common surface being magnetically attractive to particles of ferro-magnetic material;

a first electrode connected electrically to said first element;

and a second electrode connected electrically to each of said second elements.

20. A wear detector as claimed in claim 19 wherein said body is a single magnet.

21. A wear detector as claimed in claim 16 wherein the said body is a single piece of non-electrically-conductive material.

22. A wear detector as claimed in claim 16 wherein said body is of elongate rectangular configuration, wherein the first element extends adjacent one surface of the said body and terminates in an edge extending the length of said body and parallel to one longitudinal dimension thereof, and wherein the second elements are spaced from one another transversely of the body and have edges commonly aligned parallel to the edge of said first element to define between the second elements and the first element substantially straight narrow spacing gap.

23. A wear detector for use in dynamic machinery as defined in claim 16 wherein the housing is of generally cylindrical configuration having a flange;

an outwardly threaded cylindrical stub projecting from the flange, the stub being centrally bored to form an open cavity, a small central bore extending through the base of the cavity;

the magnet is a non-electrically-conductive magnet of annular configuration seated within said cavity;

a first element in the form of a circular disc bearing against the exposed face of the magnet and bolted to the housing through said small central bore;

a plurality of second elements of L-shaped cross section and generaly sector shape plan configuration;

the second elements being arranged to underlie and surround the said magnet in spaced relationship one from another;

the upstanding portions of the second elements surrounding the said magnet and extending to lie s ightly proud of the exposed surface of the magnet, there being a generally circular spacing gap between the ends of the second elements and the central circular element whereby the elements are magnetically attractive to ferro-magnetic particles;

means insulating the second element from the housan electrode extending from the base of each of the elements through bores in the floor of said cavity, said electrodes being insulated from said housing and securing said electrodes to said housing.

24. An apparatus for detecting wear in dynamic machinery employing parts made of conductive material and having fluid circulating ducts or compartments which converge downstream into a common duct or compartment comprising a first wear detector located in said c0mmon duct'or compartment having a first and a number of second conductive elements spaced apart, a plurality of second wear detectors having a first and at least one second conductive element, at least one of said second wear detectors located in at least some of said branch ducts, the first wear detector having at least the same or a greater number of second conductive elements as said second detectors in the branch ducts, a main electric circuit, the first wear detector being connected in said main electric circuit for energizing an alarm when a selected number of said second conductive elements of the first detector are conductively connected with said first element of the first detector, the second wear detectors'in the branch ducts being arranged in independently operable circuits, each of said independent circuits including electrically indicating means connected independently to each pair of contacts defined by the first elements of the second detectors on the one part and the second elements of the second detectors on the other part whereby the number of independently operable circuits energized by the second wear detectors in each said at least some of said branch ducts can be ascertained after the alarm in the main circuits has been energized.

25. An apparatus as claimed in claim 24 wherein each of the second wear detectors in the branch ducts includes an electro-magnet having a body of electrical ymagnetizable material, and wherein the said main circuit of the first wear detector in the common duct or compartment energizes the magnets of the second wear detectors in the said at least some of the branch ducts when the said selected number of the second conductive ele- 1 5 merits of the first detector are conductively connected with the first element of the first detector.

26. A wear detector for use in detecting wear in contact with a fluid in a fluid circulating system wherein chips from wearing parts are carried by the fluid, a well housing adjacent a fluid flow passage, the well housing defining a chamber, the housing defining a fluid inlet communicating said fluid flow passage with said chamber; the housing defining an outlet communicating with said chamber and said fluid flow passage downstream of said inlet; a chip detector provided in said well chamber and spaced below said inlet and outlet; the chip detector comprising an electrically-conductive body; a plurality of electricallyconductive elements adjacent a surface of the electricallyconductive body, and being spaced apart and insulated therefrom to form a gap between said body and said elements, a chip-collecting surface within said gap; the said surface of said body and the surfaces of said elements benig such as to enhance the deposition of said chips on the chip-collecting surface, each of the elements being connected through circuitry to the electrically-conductive body whereby the circuits are responsive to electrical bridging of the gaps by the deposition of Chips.

27. A wear detector as defined in claim 26 wherein the detector is provided with a cylindrical body having axial bores provided therein; the elements being in the form of elongated posts extending within said bores and insulating sleeves surrounding the posts insulating the elements from the electrically-conductive body, the body defining a surface at one end thereof with the elements terminating flush with the plane of the surface of the body, the body surface and the posts defining annular grooves about the post with the insulating sleeve forming the chip-receiving surface at the bottom of said groove.

28. A Wear detector as defined in claim 28, wherein an electrically-conductive annular ring is provided spaced above the surface of the body and is connected to a post provided in a bore of the cylindrical electrically-conductive body.

29. A wear detector as defined in claim 28, wherein the inwardly sloping walls of non-conductive material are provided above the annular ring to direct the precipitating chips towards the annular groove about the elements forming the gaps.

30. A wear detector as defined in claim 27, wherein a cylindrical filter is provided surrounding the outlet wherein the flow passing from the inlet to the outlet must pass through the cylindrical screen, the screen extending downwardly towards the detector and adapted to arrest the flow of particles in the fluid causing them to precipitate towards the detector.

31. A wear detector as defined in claim 27, wherein bafiles are provided to interrupt the flow between the inlet and the outlet of the housing whereby the bafiles cause the flow to be directed downwardly in a swirling effect enhancing the precipitation of the solid material in the fluid to precipitate towards the detector.

32. A wear detector as defined in claim 26 wherein a by-pass passage is adapted to pass the flow between the inlet and the outlet of the housing which includes a bypass gate whereby when the by-pass gate is in a by-pass position, the flow will travel to the by-pass passage, thereby avoiding the chip-collecting well, when the by-pass gate is in an open position, the flow is allowed to pass through the collecting well.

33. A method of detecting wear in dynamic machinery employing fluid circulating means such as conduits, ducts, or compartments comprising:

inserting within such circulating means a particle detector having a first and a number of second elements spaced apart to form gaps, promoting the deposition of electrically-conductive elements on surfaces in said gaps between said elements, selecting a predetermined number of second elements defining gaps with the first element, connecting the elements in an electric circuit arranged to energize an alarm when electric contact has been established between a first element and said selected number of second elements by particles of electrically-conductive material deposited by the fluid circulating in the duct.

References Cited UNITED STATES PATENTS THOMAS B. HABECKER, Primary Examiner D. L. TRAFTON, Assistant Examiner US. Cl. X.R.

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