US3289125A - Repeating circuit interrupter - Google Patents

Description

Nov. 29, 1966 K. H. DATE REPEATING CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed June 15, 1965 IIMWE 1 INVENTOR. Kazz/a flae BY M X wLWiZQ t" fittarflqy Nov. 29, 1966 K. H. DATE 3,289,125

REPEATING CIRCUIT INTERRUiTER Filed June 15, 1965 2 Sheets-Sheet 2 IN VEN TOR.

/{azz/o Date 5 W4 Wm fittorr/gr United States Patent Filed June 15, 1965, Ser. No. 464,095 8 Claims. (Cl. 335-33) This invention :relates to repeating circuit interrupters, and more particularly, to a hydraulic control mechanism for repeating circuit interrupters.

Because the majority of faults in electrical distribution systems are temporary in nature, and will clear in a relatively short time, it is common to protect such systems with repeating circuit interrupters, or reclosers, which are constructed and arranged to execute a series of successive opening and reclosing operations during which time temporary faults will normally clear. If the fault does not clear during a predetermined number of such operations, usually three, it is considered permanent and the recloser locks itself open so that the permanent fault is isolated from the source.

In addition to a repeating circuit interrupter the system may also include voltage responsive protective devices. For this reason, it is desirable that the repeating circuit interrupter close rapidly during the initial series of operations so that the voltage sensing devices will not drop out as the result of a disappearance of system voltage which would occur if the repeating circuit interrupter remained open for an appreciable period. On the other hand, for proper coordination with other protective devices in the system, it is also desirable that reclosing be delayed after the initial series of rapid opening and reclosing operations.

It is an object of the invention to provide an automatic protective device with a hydraulic control mechanism capable of varying the reclosing time after an initial series of rapid reclosing operations.

A more specific object of the invention is to provide a hydraulic control mechanism for a repeating circuit interrupter with valve means which is operable to one of a plurality of successive positions upon each switch opening operation for controlling the time delay of each reclosing operation.

These and other objects and advantages of the instant invention will become more apparent from the detailed description thereof taken with the accompanying drawings in which:

FIG. 1 is a side elevational view, with parts broken away, of a repeating circuit interrupter incorporating the instant invention;

FIG. 2 is a side elevational view, partly in section, of the hydraulic operating mechanism of the repeating circuit interrupter illustrated in FIG. 1; and

FIGS. 3 and 4 illustrate fragmentary portions of the operating mechanism shown in FIG. 2.

Referring now to the drawings in greater detail, FIG. 1 shows a repeating circuit interrupter or recloser incorporating the instant invention and including a metallic housing or tank 11 which is closed at its upper end by a gasketed cover 13 from which the internal operating mechanism is suspended on insulating supports 14. Tank 11 is ordinarily filled with dielectric fluid, such as oil, to the level indicated by .the dashed line 15.

The cover 13 also supports a pair of insulating bushings 16, only one of which is shown in FIG. 1. The bushings 16 extend interionly of the tank 11 and beneath the oil level 15 for serially connecting the recloser 10 in the system being protected. As those skilled in the art will appreciate, the current path between the bushings 16 and through the recloser 10 constitutes a series circuit which includes an electromagnetic operating coil 17 and an interrupting switch assembly generally designated by the reference numeral 18.

In order to correlate the various portions of the repeating circuit interrupter 10 shown in FIG. 1, its operation will now be discussed in general terms. Each time an overcurrent occurs in the system being protected, and electromagnetic plunger 19 is attracted downward-1y into the series connected operating coil 17 to move an operating rod 20, connected to its lower end, into engagement with an overcenter operating mechanism 24 of the interrupter switch 18. This pivots a movable contact arm 21 around a pin 26 and into its open position. With the interrupting contacts 18 open, the series coil 17 is dc-energized so that the overcenter mechanism 24 elevates the electromagnetic plunger 19 to rotate the contact arm 21 counterclockwise into its closed position.

Although the details of the overcenter mechanism 24 form no part of the instant invention, it will now be briefly described so that the operation of those portions of the repeating circuit interrupter 10 which comprise the instant invention can be more easily understood. As seen in FIG. 1, the lower end of the rod 20 rests on a roller 119 carried at one end of a lever 121), the other end of which is p-ivotally mounted on a fixed pin 121. A long link 122 is connected at one end to the lever and extends downwardly therefrom where its opposite end is connected by a pin 127 to one end of the short link 125 whose other end is provided with an elongate slot 123 -for slidably engaging a fixed pin 124. An overcenter spring 126 extends between the pin 127 and a bracket member 128 extending upwardly from the contact arm 21. In addition, a link 130, pivotally mounted at 131, is coupled to the pin 127. When the circuit interrupter is in its closed position, shown in FIG. 1, the spring 126 exerts an upward force on link 122 to hold the plunger 19 in its elevated position.

As will be described more fully herein-below, each time the magnetic plunger 19 is depressed upon the occurrence of an abnormal circuit condition, an insulating stem 22 connected to its upper end is operative through the agency of a bell crank 23 to depress a pump piston 25 so that a measured quantity of hydraulic fluid is delivered to a hydraulic integrating mechanism 27. Upon each pumping operation a stem 28 extending outwardly from the integrating mechanism 27 is advanced a predetermined distance toward a trip finger 29. After a predetermined number of such switch opening and reclosing operations, the stem 28 will engage the finger 29 to release the overcenter lockout mechanism 30 which in turn will engage the crank 23. This rotates the crank 23 counterclockwise so that the magnetic plunger 19 is held in its depressed position to prevent closure of the main interrupting contacts 18 until they are manually reset.

Certain of the various details of the repeating circuit interrupter just discussed form no part of the instant invention and, accordingly, will not be discussed in detail for the sake of brevity. For a more complete description of these details, reference is made to Patent 2,92t 5,228 which is assigned to the assignee of the invention.

As seen more particularly in FIG. 2, the magnetic plunger 19 descends through a bore 35 formed in a casting 31 which also contains the pump piston 25 and the integrating assembly 27. A dashpot cylinder 37 is disposed coaxially within the bore 35 for receiving the magnetic plunger 19 and is formed by the insulating spool 38, upon which the series operating coil 17 is wound. An aperture (not shown) is provided in the lower end of the dashpot cylinder 37 to allow the operating rod 20 to pass therethrough for engagement with the overcenter assembly 24 as discussed hereinabove. The magnetic circuit for the flux emanating from the coil 17 includes the plunger 19, the metallic casting 31, a metallic base plate 32 and metallic support brackets 33 which extend between the casting 31 and the plate 32. The brackets 33 and metallic rods 34 support the coil 17 and the base plate 32 which, in turn, support the integrating switch assembly 18.

As seen in FIG. 2, the pump piston 25 is disposed for reciprocal movement within a cylinder 40 formed in the casting 31 and has a stem 41 extending upwardly there-' from and connected at its upper end to a pin 42 carried by one arm 44 of the bell crank 23 (see FIG. 1). The other end of crank arm 44 is pivotally connected at 45 to the upper end of the plunger stem 22.

The lower end of the cylinder 40 is connected by a semicircular duct 48 formed in the bottom of the casting 31, to the lower end of an integrating cylinder 50 which is part of the integrating mechanism 27. The duct 48 is sealed by a flat gasket plate 51 held against the lower end of casting 31 by a circular washer plate 52 which is disposed between the spool 38 and the lower surface of the casting 31 and which has an aperture 53 for passage of the magnetic plunger 19.

A discharge duct 58 connects a slide valve cylinder 59 with the dashpot cylinder 37. When the plunger 19 is attracted downwardly, fluid in cylinder 37 is displaced and discharged through the duct 58 and into the slide valve cylinder 59. Slide valve 60 is disposed at the upper end of the cylinder 59 and is normally biased against a shoulder 61 by a compression spring 62. During opening operations of the recloser, fluid pressure developed by the descent of plunger 19 causes slide valve 60 to be elevated against compression spring 62. The elevation of slide valve 60 opens an escape port 65 which leads from the slide valve cylinder 59 to open the upper end of the integrating cylinder 50 so that fluid passing through the port 65 is free to discharge into the body of fluid within the tank 11.

A ball check valve 70 connects the lower end of integrating cylinder 50 to the duct 48 to permit the easy ingress of fluid into cylinder 50 and to prevent the discharge thereof back into the duct 48. The integrating assembly 27 also includes a piston 71 which carries the stem 28 at its upper end and which is biased for return toward the lower end of cylinder 50 by a return spring 72.

As seen in FIG. 3, elevation of the slide valve 60 also exposes one of a plurality of orifices 74 formed in an orifice plate 75 which may be rotated into registry with a passage 76 opening into the cylinder 59.

In order to more fully appreciate the instant invention, the operation of those conventional portions of the recloser which have been mentioned heretofore will now be discussed. Upon the occurrence of an overload current to the coil 17, plunger 19 will be attracted downwardly through the bore 35 in the casing 31 and into the dashpot cylinder 37. The initial movement in the plunger 19 will be substantially unimpeded because a plurality of axial surface slots formed in the plunger 19 allow the fluid from the dashpot cylinder 37 to discharge freely along the plunger. However, when the plunger 19 has descended to the point where the upper ends of the slots 81 move past shoulder 82 formed in the upper end of the bore 35, the slots 81 will be closed by the wall of said bore so that retarded descent of the plunger 19 begins. Fluid forced from dashpot cylinder 37 when the slots 81 are closed, passes through the duct 58 forcing the slide valve 60 upwardly and escapes through the escape port 65.

Downward movement of the plunger 19 will also pivot crank 23 counterclockwise to force stem 41 downwardly, thereby moving the pump piston 25 into the pump cylinder 40. Upon the initial descent of the pump piston 25 the hydraulic fluid in the lower end of the cylinder 40 will be discharged through a relief port 84 until the lower end of said piston has been depressed sufiiciently to cover this opening as seen by phantom lines in FIG. 2. Thereafter, as the piston 25 descends, the fluid in the lower end of cylinder 40 will be delivered to the lower end of the cylinder 50 through the duct 48 and past the ball check valve 70. This moves the integrating piston 71 a predetermined distance upwardly against the return spring 72, so that the stem 28 is elevated a predetermined distance toward the trip finger 29 of the lockout mechanism 30.

The downward movement of the plunger 19 will also rotate link clockwise to force links 122 and downwardly as the link pivots counterclockwise to swing pin 127 in an are about pin 131. This action continues until the roller 119 impacts a second roller 132 carried by the bracket member 128 to pivot the switch arm 21 clockwise. Simultaneously the line of action of spring 126 moves past the pivotal axis of switch arm 21 whereupon the main switches snap clockwise, opening the interrupting contacts. Upon the disappearance of line current in coil 17, the overcenter spring 126 will tend to move the links 122 and 125 upwardly thereby elevating the plunger 19. This will continue until the upward movement of the pin 127 brings the line of action of spring 126 past the pivotal axis of switch arm 21, whereupon the switch arm will again be in an overcenter posi tion and will snap into its closed position. Should the fault reappear upon the closing of the main interrupting contacts 18, the plunger 19 will again be attracted downwardly to open the main interrupting contacts 18 and to depress the pump piston 25 into the pump cylinder 40 to deliver a second measured quantity of hydraulic fluid below the integrating piston 71, so that it will be moved a second distance toward the trip finger 29. This will move the piston 71 to the point Where it covers the escape port 65 in the slide valve cylinder 59.

Should the fault reappear after the second closing operation, the plunger 19 will again be retracted downwardly into the dashpot 37. However, its descent will be further retarded by the closing of the escape orifice 65, since the fluid displaced from cylinder 37 must now discharge through the relatively small opening 74 in the orifice plate 75.

After the interrupting contacts have been opened for the third time, they will again be closed by the action of the overcenter spring 126 described above. Should the overload current appear for a fourth time, the plunger 19 will again be attracted downwardly, causing a fourth measured quantity of fluid to be delivered from the pump piston 25 to the integrating piston 71 which moves the stem 28 into engagement with the trip finger 29, causing the main contacts to be locked in an open position. Piston 71 then resettles to its initial position in the lower end of the cylinder 50 as a result of the action of the return spring 7 2.

It will be appreciated that the rate at which the magnetic plunger 19 can be elevated by the overcenter spring 126 to perform a switch closing operation is controlled by the rate that fluid can be drawn into the cylinder 37 and below the plunger 19. The reclosing time delay assembly 88 controls this return flow of fluid to the cylinder 38 and hence the delay of the switch closing operation.

The closing time delay assembly 88 includes a cylinder 89 formed in the casting 31 adjacent the slide valve cylinder 59 and in substantial parallelism therewith. A control piston valve 90 is disposed for reciprocal movement within the cylinder 89 and is urged toward the lower end thereof by a reset spring 91. Three cross passages 92, 93 and 94 are formed in the casting 31 and extend transversely from its outer surface to the cylinder 89. A reclosing time adjusting plate 95 is mounted on the outer surface of the casting 31 adjacent the apertures 92,

93 and 94 and is secured thereto by a screw '96 which engages a suitable tapped pole in said casting.

The reclosing time adjusting plate 95 has four rows of apertures 97a97d which are so arranged that all of the openings in any row may be simultaneously placed in registry with one of the passages 92, 93 and 94.

As seen in FIG. 4 the first row of apertures 97a has three large openings, the second row 97b has two large openings and one small opening, the third row 970 has one large opening and two small openings and the fourth row 97d has three small openings. The purpose of varying the sizes of the apertures in this manner will be explained in greater detail hereinafter. In addition, the plate 95 has an additional aperture 98 diametrically opposite each of the rows of openings 97a97d so that the plate may be secured in each of its alternate positions by a pin 99.

A stem 100 extends upwardly from the piston valve 90 and through the open upper end of the cylinder 89 and is threaded at its upper end for receiving an adjustable pick-up nut 101.

The lower end of the cylinder 89 is connected by a ball check valve 102 and a port 103 to the slide valve cylinder 59. The check valve 102 is disposed in such a manner that it permits fluid flow from the cylinder 89 to the slide valve cylinder 59 but prevents fluid flow in the opposite direction.

The piston 90 has a longitudinal passage extending axially from its lower end for communicating with the ball check 102. In addition, an annular recess 105 is formed intermediate the ends of the outer surface of the piston 90 and communicates with the passage 104 by a plurality of radial ports 106.

When the piston 90 is in its initial position, as shown in FIG. 2, the annular recess 105 is disposed adjacent the lowermost of the transverse pas-sages 92 formed in the casting 31. As a result, the passage 104 in piston 90 IS in communication with the ambient fluid surrounding the casting 31 through the ports 106, the annular recess 105, the passage 92 and the lowermost one of the openings 97b.

It will be recalled that on the occurrence of an overload current in the coil 17 the plunger 19 will bedrawn downwardly into the cylinder 38 to open the mam contacts 18. The fluid within the cylinder 37 is expelled through the aperture 53 and the discharge duct 58 into the slide valve cylinder 59 from which it exhausts to the ambient fluid as previously described. When the main switches 18 open to interrupt current to the C011 17, the spring 106 urges the plunger 19 upwardly.

During this first opening operation the integrating piston 71 will be elevated a first incremental distance. The adjustable pick-up nut 101 is positioned on the stem 100 in such a position relative to a transverse arm 108 extending from the trip rod 28 that when the integrat ng piston 71 is elevated during the first opening operation the arm 108 will just move into engagement with the nut 101 without raising the piston 90.

Thus, after the first switch opening operatlon, the piston 90 will remain in its position shown in FIG. 2 so that as the plunger 19 begins raising as a result of the action of spring 126, fluid will be drawn beneath the piston 19 through the path defined by the lowermost large aperture 97b in plate 95, passage 92, recess 105, ports 106, check valve 102, port 103, and the aperture 53. As a result, the first closing operation will be rapid.

Should the fault reappear when the main contacts 18 are fully closed, the plunger 19 will again be drawn downwardly to open the main contacts and to raise the piston 71 a second incremental distance. This, in turn, raises the piston 90 through the agency of the stem 100, the pick-up nut 101 and the arm 108 so that the recess 105 is opposite the second transverse passage 93. As a result fluid may be drawn beneath the plunger 19 during the second switch closing operation through the second large aperture 97b in'plate so that the second closing operation is also rapid. However, after the third opening operation the piston 90 will be elevated to the point where the recess is opposite the third passage 94 so that when the plunger 19 is raised a third time fluid must be drawn through the relatively small aperture 97b". As a result the upward movement of the plunger 19 will be retarded so that the third closing operation will be delayed relative to the first two closing operations.

After the interrupter has cycled to lockout or after the fault has cleared during a lesser number of operations, the integrating piston 71 will be returned to its initial position by spring 72 so that the spring 91 may also return the piston 92 its initial position shown in FIG. 2.

It will be appreciated that by positioning any of the other rows of apertures 97a, 97c or 97d opposite the passages 92, 93 and 94, different combinations of rapid and retarded closing operations may be obtained.

While only a single embodiment of the instant invention has been shown and described it is not intended to be limited there-by but only by the scope of the appended claims.

I claim:

1. An automatic protective device including switch means in circuit with the system being protected, hydraulic integrating means, coupled to said switch means, circuit condition responsive means coupledto said system and to said switch means for opening said switch means and for actuating said integrating means upon the occurrence of predetermined circuit condition, switch closing means for closing said switch means after an opening operation thereof, said hydraulic integrating means including valve means coupled to said switch means and having an initial position and a plurality of alternate positions and being sequentially movable through said alternate positions upon each switch opening operation, hydraulic time delay means coupled to said switch closing means, said valve means being coupled to said time delay means and being operative in each of its alternate positions for controlling the delay thereof.

2. An automatic protective device including switch means in circuit with the system being protected, hydraulic integrating means coupled to said switch means, circuit condition responsive means coupled to said system and to said switch means for opening said switch means and for actuating said integrating means upon the occurrence of predetermined circuit condition, switch closing means for closing said switch means after an opening operation thereof, normally inactive lockout means operable to effect a continuous switch open condition, said hydraulic integrating means being operable after a predetermined number of switch opening operations to render said lockout means effective, valve means coupled to said switch means and having an initial position and a plurality of alternate positions and being sequentially movable through said alternate positions upon each switch opening operation, hydraulic time delay means coupled to said switch closing means, said valve means being coupled to said time delay means and being operative in each of its alternate positions for controlling the delay thereof.

3. An automatic protective device including switch means in circuit with the system being protected, hydraulic integrating means, abnormal condition responsive means coupled to said system and to said switch means for opening said switch means and for actuating said integrating means upon the occurrence of an abnormal circuit condition, switch closing means for closing said switch means after an opening operation thereof, normally inactive lockout means operable to eflect a continuous switch open condition, said hydraulic integrating means being operable after a predetermined number of appearances of said abnormal circuit condition to render said lookout means eifective, said hydraulic integrating means including valve means having an initial position and a plurality of alternate positions and being sequential-ly movable through said alternate positions after each switch opening operation, hydraulic time delay means coupled to said switch closing means, said valve means being coupled to said time delay means and operative in each of its alternate positions for controlling the delay thereof.

4. An automatic protective device including switch means in circuit with the system being protected, abnormal condition responsive means including a coil coupled to said system and a magnetic plunger coupled to said switch means, a hydraulic cylinder for receiving said plunger, said plunger being moved into said cylinder by said coil upon the occurrence of an abnormal circuit condition to open said switch means, switch closing means for closing said switch means after an opening operation thereof and for moving said plunger outwardly of said cylinder, valve means coupled to said plunger and having an initial position and a plurality of alternate positions and being sequentially movable to one of said alternate positions after each switch opening operation, said valve means being coupled to said cylinder and being operable in each of its positions to control the return flow of hydraulic fluid thereto when said plunger is moved outwardly thereof by said switch closing means to delay the closing of said switch means, and means for adjusting said valve means in each of its positions so that the time delay at each position may be controlled.

5. An automatic protective device including switch means in circuit with the system being protected, closing spring means coupled to said switch means, abnormal condition responsive means including a coil coupled to said system and a magnetic plunger coupled to said switch means, a hydraulic cylinder for receiving said plunger, said plunger being moved into said cylinder by said coil upon the occurrence of an abnormal circuit condition to open said switch means and to charge said closing spring means, saidclosing spring means being operative to close said switch means after an opening operation and to move said plunger outwardly of said cylinder, hydraulic valve means coupled to said plunger and having an initial position and a plurality of alternate positions and being sequentially movable to one of said alternate positions after each switch opening operation, said valve means being coupled to said cylinder and being operable in each of its positions to control the return flow of hydraulic fluid thereto when said plunger is moved outwardly thereof by said closing spring to delay the closing of said switch means.

6. An automatic protective device including switch means in circuit with the system being protected, hydraulic integrating means, abnormal condition responsive means including a coil coupled to said system and a magnetic plunger coupled to said switch means, a cylinder for receiving said plunger, said plunger being moved into said cylinder by said coil upon the occurrence of an abnormal circuit condition to open said switch means, switch closing means operative to close said switch means after an opening operation and to move said plunger outwardly of said cylinder, normally inactive lockout means operable to efiect a continuous switch open condition, said hydraulic integrating means being operable after a predetermined number of appearances of said abnormal circuit condition to render said lockout means eflective, valve means coupled to said switch means and having an initial position and a plurality of alternate positions and being sequentially movable to one of said alternate positions after each switch opening operation, said valve means being coupled to said cylinder and being operable in each of its positions to control the return flow of hydraulic fluid thereto when said plunger is moved outwardly thereof by said switch closing means to delay the closing of said switch means.

7. An automatic protective device including switch means in circuit with the system being protected, abnormal condition responsive means including a coil coupled to said system and a magnetic plunger coupled to said switch means, a hydraulic cylinder for receiving said plunger, said plunger being moved into said cylinder by said coil upon the occurrence of an abnormal circuit condition to open said switch means, switch closing means operative to close said switch means after an opening operation and to move said plunger outwardly of said cylinder, valve means coupled to said switch means and having an initial position and a plurality of alternate positions and being sequentially movable to one of said alternate positions after each switch opening operation, said valve means being coupled to said cylinder and being operable in each of its positions to control the return flow of hydraulic fluid thereto when said plunger is moved outwardly thereof by said switch closing means to delay the closing of said switch means.

8. An automatic protective device including switch means in circuit with the system being protected, hydraulic integrating means, closing spring means coupled to said switch means, abnormal condition responsive means including a coil coupled to said system and a magnetic plunger coupled to said switch means, a cylinder for receiving said plunger, said plunger being moved into said cylinder by said coil upon the occurrence of an abnormal circuit condition to open said switch means and to charge said closing spring means, said closing spring means being operative to close said switch means after an opening operation and to move said plunger outwardly of said cylinder, normally inactive lockout means operable to effect a continuous switch open condition, said hydraulic integrating means being operable after a predetermined nu-mber of appearances of said abnormal circuit condition to render said lockout means effective, said hydraulic integrating means including valve means having an initial position and a plurality of alternate positions and being sequentially movable to one of said alternate positions after each switch opening operation, said valve means being coupled to said cylinder and being operable in each of its positions to control the return flow of hydraulic fluid thereto when said plunger is moved outwardly thereof by said closing spring to delay the closing of said switch means, and means for adjusting the flow rate through said valve means in each of its positions so that the time delay at each position may be controlled.

No references cited.

BERNARD A. GILHEANY, Primary Examiner.

R. N. ENVALL, ]R., Assistant Examiner.

Claims (1)

1. AN AUTOMATIC PROTECTIVE DEVICE INCLUDING, SWITCH MEANS IN CIRCUIT WITH THE SYSTEM BEING PROTECTED, HYDRAULIC INTEGRATING MEANS, COUPLED TO SAID SWITCH MEANS, CIRCUIT CONDITION RESPONSIVE MEANS COUPLED TO SAID SYSTEM AND TO SAID SWITCH MEANS FOR OPERATING SAID SWITCH MEANS AND FOR ACTUATING SAID INTEGRATING MEANS UPON THE OCCURRENCE OF PREDETERMINED CIRCUIT CONDITION, SWITCH CLOSING MEANS FOR CLOSING SAID SWITCH MEANS AFTER AN OPENING OPERATION THEREOF, SAID HYDRAULIC INTEGRATING MEANS INCLUDING VALVE MEANS COUPLED TO SAID SWITCH MEANS AND HAVING AN INITIAL POSITION AND A PLURALITY OF ALTERNATE POSITIONS AND BEING SEQUENTIALLY MOVABLE THROUGH SAID ALTERNATE POSITIONS UPON EACH SWITCH OPENING OPERATION, HYDRAULIC TIME DELAY MEANS COUPLED TO SAID SWITCH CLOSING MEANS, SAID VALVE MEANS BEING COUPLED TO SAID TIME DELAY MEANS AND BEING OPERATIVE IN EACH OF ITS ALTERNATE POSITIONS FOR CONTROLLING THE DELAY THEREOF.

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