US1898228A - Electromagnetic release valve - Google Patents

Description

Feb. 21, 1933. R.. F THOMPSON 1,898,228

ELECTROMAGNETC RELEASE VALVE Filed Dec. 2l, 1929 3 Sheets-Sheet l Ii\\\ g: t:

|| @sau/am Feb. 21, 1933. R. F. THOMPSON ELECTROMAGNETIC RELEASE VALVE Filed Deo. 2l, 1929 5 Sheets-Sheff Feb. 21, 1933. R. F. THOMPSON ELECTROMAGNETIC RELEASE VALVE Filed Dec. 2l, 1929 3 Sheets-Sheet i Patented ret. 21, 1883 UNITED lSTATES. PA'riaN'r OFFICE.

'myn F. THOMPSON, or nas'r LIvnarooL, omo; saam mccnncon -zrnoxrsom ADMINISTRATRIX. OF SAID RALPH F. THOMPSON, DECEASEIQ, ASBIGNOB T SARAH MACGREGOR THOHPSON, 0F"SEWICXLEY, PENNSYLVANIA nnncraoncmirrc anu-.asn van'vn provide an electromagnetically controlled fluid device for automatically opening switches at an electric railway substation to better protect the equipment of such substations against abnormal conditions, more particularly, to protect the synchronous. converter against flash-overs, due to direct curren short-circuits and overloads.

Another object of my invention is to rovide an electromagnetcally controlled uid device for opening switches at a railway substation .in a shorter interval of time than is required for the opening of the circuit breakers usually employed on the trolley cars which are fed from the substation.

' Another object of my invention is to provide an electromagnetic release valve for releasing a fluid under pressure from within a vessel, which will release the fluid more quickly than devices of the prior art have been capable of doin A v A further object o my invention is to rovide an electromagnetically controlled uid device for openingelectric switches, which -will insure v'a very rapid o ning of the switcheswhen abnormal con ltions occur in lthe-circuits in which the switches are lo i prevent the valve from stickintgkparticularly the magnet' amature thereo 1 venting `considerable damage to substation ereby preequipment. v v s Another object is to provide an electroetic release valve'and-m ctr-valves which; will function more 'elci'ently and l'which will -require le control energ for their operation, thereby reducing the maximally raised position.

mum demand on the current control supply of a substation and eliminating storage batteries, which are generally found necessary in connection with the control current-supply to maintain the required voltage, to effect a material saving in the cost of maintenance of the substation.

A still further object is to provide a magnet-valve which is suliicientl sensitive in itself to eliminate the use o delicate relays which have been necessary heretofore.

Other objects and advantages will appear more fully hereinafter from the following detailed descriptiontogether with the drawings, in which:

Fig. 1 is a sectional view of the electromagnetic release valve of my invention and my improved magnet for a magnet-valve;

Fig. 2 is a detailed front view of the inter-l lock switch mechanism; and

Fig. 3 is a schematic electrical diagram of an elementary substation circuit showing the location of the valve of my invention therein.

The type of switch generally used heretofore, known as an electro-pneumatic contactor, comprises a cy inder mounted in a vertical osition, the lower head of which is provided) air, or other fluid under pressure, to and to.

exhaust it from the cylinder and is known as a' magnet valve. A piston is normally. held in a vertically raised position in the cylinder by compressed air,' or other fluid admitted tothe cylinder, and to the external end of the piston or piston rod is attached one of with a projection which forms af', support for a magnetically operated .valve the 'contacts of the contacter which keeps the contactor closed when the iston is in its normined over-load occurs on the line or a sh0rtcircuit on the. feeders, the magnet valve-is actuated'to exhaust the fluid from the cylinder, thereby permitting the piston to be forced downwardly by the action of a heavy spring thus causing the contactor switch to open. The magnet-'valve sometimes becomes f en a predeter.

inoperative due to the sticking of the parts,

Aparticularly the magnet armature. This failure, Whilel alwayscausing an interruption of the power supply to the railway, also frequently causes considerable damage to substation equipment. The application of my invention to the magnet-valve eliminates the possibility of such sticking.

The above description may be more clearly followed from Fig. 1, in which the upper half of the device, i. e., above thel supports 5.8 corresponds to a pneumatic contactor cylinder and piston of the prior art; a novel feature of my invention `being in providing an exhaust port in the bottom of the cylinder in addition to the exhaust port 61 provided in the magnet valve at the right supported on the bracket 57, and in providing my improved electromagnet to open and close said port.

It was found that in applying the devices of the prior` art for the opening of electrical contractors, the opening was not suciently which would cause flash-overs. VBy providing my improved release valve, which provides a very rapid action and opens the load limiting contactor beforethe circuit breakers on thev car are opened, the short-circuit current is reduced byvirtue of heavy grid resistors which are connected across the contactor, so that the load on the line is largely reduced and when the circuit breakers on the car do function, a much smaller current is broken, thereby preventing the Hash-overs on the synchronous converter. To produce this quick action, I have provided an exhaust port in the bottom of the cylinder which permits the fluid to be exhausted from the cylinder `more rapidly than through the exhaust port provided in the magnet valve and an imf in said port.

proved electromagnet for opening and closeferring to Fig. 1, my device in its'entirety comprises the usual cylinder 1 provided with a piston 2 adapted to be moved in the cylinder against the action o the spri'ng 40 by the iluid under pressure entering through the .inlet port 4 and the valve-23 through the passage 3V to the piston 2. The

admission of the fluid from the inletport 4 to the passage 3 is controlled by the valve 23 which is held open by means ofthe electromagnetic device attached to the valve stem 26 and which comprises electromagnet 17 en-I ergized by means of a shunt coil 20. The electromagnet is of the iron-clad fiat-coil type, the tractive power of which is relatively small but the holding power is relatively large. Normally, the shunt coil 20 is energized, thereby energizing the magnet 17, which. in turn, attracts the flat disk armature 16. The armature 16 is mounted on a sleeve 15 through which the extension 34 or the valve stem 22 of the valve 18 is adapted to slide. The valve 18 is kept on itsseat by the-action of. the spring 36 whichis compressed against the valve stem by the action of the armature 16 when it is in magnetic contact with the magnet 17. The nuts 38 are provided for varying the compression of the spring 36, that is, to vary its initial compression.- When the armature 16 forces the sleeve 15 down on the spring 36, the -spring is given its inal compression, sealing the valve 18 by transferring the pressure of the spring from the nuts 38 to the valve seat and leaving a small gap between the nuts and the armature 16. The valve 18 is normally closed when the valve'23 is held open, since they are integrally united by the valve stem 26. The function of the shunt coil 2() is to normally hold the armature 16 in contact with the magnet 17, thereby maintaining the valve 18 closed, so as to prevent the fluid under pressure escaping through the exhaust port 61. A cross-head is attached to the end Y of the piston rod 62 of piston 2 which maintains the movable contact of the electrical. contactor in a closed position when the piston is inits raised position, as indicated in the drawings. In addition tothe shunt coil 20,

I provide a series coil 63 comprising one turn of .comparatively heavy wire wound around the core of magnet 17 or around the coil 2O and energized iman opposite direction to the windings of the coil 20. Normally, the coil 63 is not provided with suiicient energy to. y

vcounteract-the iiux of the coil 20, because it carries only a very small portion of the load current. However, when the load onthe line rises toga predetermined over-load (Fig. 3),

a comparatively large current is caused to iow through the -serles coil and this current counteracts the action of coil 20, thereby demagnetizing the magnet 17.l and permitting. Y

the spring 36 to -movethe armature 16 which then releases the compression of'l the spring 36, thus permitting the fluid under` pressure to raise the valve 1 8 and permit the fluid to be exhausted through the port 61. Valve 18 is slightly accelerated by a momentary re` "pulsion betweenthe magnet 17 and armature 16. As soonas theI fluid is exhausted, the

piston 2 is caused to move downward by the action of the spring 40, carrying with it the' cross-head 60 and the Amovable contact ofthe contactor or switch, thereby breaking the circuit. of the line. This action in itself is suiiicient only when over-loads occur on the line,but in the case of short-circuits on trolley cars fed by the line, additional means is required ,to speedl up the release action of the piston so that the contacter may be opened sooner than the circuit breakers are tripped on the trolley car. To accomplish this, I provide an additional exhaust port 5 and a valve 6 for keeping it `closed in its normal position, the ,valve being-held\against its seat bythe action of the 4the spring 14. The spring 14 is given its initial compression by means of the head 7 of the sleeve 41 which is threaded in the disk armature -8. The compression of the spring 14 may be adjusted by means of nuts 42 which are attachedrtol the end of the valve stem 9. The nuts 50 are for the purpose of affording a larger bearing ysurface for the pressure of nuts 42 against the end of sleeve 41. A final compression is given to the spring 14' by Umeans of the armature 8 when itis attracted by the magnet 10. The magnet 10 is similar to the magnet 17 lof the magnet-valve and is also 4provided with a shunt coil; 19 and a series coil 64,' both of which function in exactly the same manner as coils 20 and 63. However, coil 64 is connected across an'inductive shunt 72, as indicated in Fig. 3.

The inductive shunt-does not materially affect the division of normal load current between the bus and the series coil 64.` The resistance of the Asection of-bus shunted by the' series coil and the resistance of the series coil 64 with its connections to the bus are so proportioned that the load current passing through the series coil 64 is not suiicient to counteract the effect-of the current in shunt coil 19 and demagnetize the magnetl() until the load is permitted to reach an amount greater than that at which the magnet valve (17-'-18) is adjusted to open the contactor 73,

that -is, at normal over-loads the magnet valve 17-18 operates to'open the contacter 73 before the load rises to an amount sufficient to eifectthedemagnetization of magnet 10 and open the release valve 6. However, when a sudden and large rush of current occurs, as on the occurrence ofl a shortcircuit on the feeders, the reactance of the inductiveshunt momentarily forces a ,comparatively large currentthrough the coil 64, counteracting the current in coil.19, vdemagnetizing the magnet '10 and releasingfitsarmature 8, thereby releasing the valve 6 and permitting it to be forciblyzfopened by the".

air pressure from the cylinder 1.- The motion of the valve 6 is also accelerated lby a momentary repulsion between the armature o 8 and the magnet 10 due to the sudden rush yof current invcoil '64.

.'sNormally,` the armature 8 is in contact withthe magnet 10 by the .action of the coil 19 to keep the valve stem 9 in a raised position, thereby holding the valve r6 against its seat and keepingthe exhaust port 5 closed.

The electromagnet com rising vthe magnet 10 and the coil 19 is of tlie iron-clad flat-coil type enclosed in a shell and having a weak tractive power but a comparatively high holding power similar to magnet 17 and coil 20. By using this form of electromagnet and a light disk armature, a smaller amount of control current is required to hold the armature 8 against the magnet than is required in the usual form of electromagnet used in control work in which a large'mass of iron and a relatively long coil are used, making it diiiicult to demagnetize the core quickly.

The low tractive power of the electromagnet is compensated for b providing a light restoring' spring 13. he force of spring 13 is so small that it will barely sustain the weight of the armature and the parts attached to it and will not materially oppose the opening of the valve 6. The adjustment of this spring may be made by the screw 27 threaded in the iron base 51 and locked by lock nut 28. The purpose of therestoring spring 13 is to restore the armature 8 into close proximity to the magnet 10 after an opening has occurred, thereby giving the electromagnet only the function of givingthe spring 14 its final compression which may be approxi- After the armature 8 is in Contact with the magnet 10, itcanbe easily held and with a small fraction of the ampere turns required to pull it into contact against the action of spring 14. This is taken advantage of to save control energy and, more particularly,

to reduce the ampere turns to permitl a'V quicker release of the armature 8 by inserting a resistance 1' in series with the shunt coil 19 of the magnet-by means of the interlock switch 81 (Fig. 3) when the contacter closes,

thereby reducing the current to about onetenth of the amount required during the closingoperation of the release valve. A similar resistance r1 with interlock 84 is provided for the coil 19., Another interlock switch' 34 is prgvided in series with 'theshunt coil 20 of the` magnet-'valve by means of the terminals 45 and 46 (as shown in Fig. 1 and Fig. 3) to prevent any possibility of the magnet- .valve becoming energized and closing the valve 18 and .admitting Huid to the cylinder before the release valve 6 is sealed by the armature 8- cominginconta'ct with its magnet 10 and also to assure the demagnetiza'tion of the magnet-valve when the release `valve opens to avoid the fluid being forced through thevalve 23 from the inlet port 4. The interlock switchI 34 comprises a lever 11 piv- 'i 1 and 2).

oted at 65 andhaving a shoulder 66 which is actuated by the amature 8 when the armature is in contact with the magnet 10 (Figs.

The section 44'is of insulating material and a flexible connection 67 is provided from the lower brass end 68 of the lever 11 to the binding post 45. The other connection is made to post 46 from the stationary contact bracket 47., The purpose of the lever of the interlock switch is to multiply the movement produced by the armature 8 to close contacts 34. It might be possible under some conditions for thearmature 8 to fail to pull inthe last small fraction of an inch necessary to transfer the pressure of the compression spring 14 from the nut- 42 to the valve seat of valve 6 and in such a case, the magnet-valve must not be permitted to ad` mit fluid to the cylinder. Therefore, the interlock switch 34 must be operated by the last small fraction of an inch of travel of the armature and this fraction may be about .02 of an inch. The adjusting screw 12His provided for the adjustment of the stationary contact 21. The insulation 44 is in two strips, one secured to either side of the brass end pieces with asmall space between them forming a slot as indicated in Fig. 2. Through this slot, the flat stud 33 passes to act as a guide for the interlock arm. Spring y32 opens the interlock when armature 8 falls away from the shoulde'r`66 of the lever 11. The strips 52, ,between which is mounted the iron bracket 51, are of insulating material, such as some phenol condensation product, hard rubber and the like. The screw 35 is a ilister-head screw and is provided "for attaching the terminal block 29 to the device. The terminals 30 and 31 are one of the ter- .minals of each of the series coils 64 and 63,

respectively. The terminals of the shunt coils are not known. A

In the case of the magnet-valve, the magnet 17 `is screwed into a portion of a magnetvalve and prior art-at 54. Spring 25 of the magnet-valve is for the purpose of raising the valve 24 against its seat when thema'g-` 'net 17 has been demagnetized and' 1s held against the valve 24 by means of the retainingnut 55. y

An additionalv featurev of my invention is the provision of an improved armature for the electromagnets of both the magnet-valve and the release valvev which is so` constructed n that' any tendency for the armature -to become cock d'thereby causingA the valves to stick', isavoided. This is accomplished first, by providing' the arrangement of the sleeves to which the flat disk armatures are attached and through whichthe valves and valve stems are guided as a unitand. constructing thisassembly sq that its length K diameter, l,and then making. he' sleevesand varmatures integral so that the armatures inf.

5 all positions will be held rigidly .parallel to ,Ieaterthan its g the faces of their magnets, for the purpose l of preventing binding due to any unequal attraction between the armatures and their magnets.

full current had to be maintained through the holding coil and even then the armature' would be released if the control voltage dropped about fifteen percent, while actually,

should be held at least until thesubstation shuts .down automatically on low voltage, the shutting-down point being about twenty percent below normal voltage. With my imy In the magnet-valves of the prior' art, 'the armature generally consisted of a relatlvely short hollow cylinder closed at one proved elcctromagnet, the current through the coil of the electromagnet is reduced to about one-tenth of the amount required to close it and the magnet will hold the armaturc until the control voltage `dro s to` thirty percent'below normal. These eatures assure more efficient operation of the valves and all tendency of the valves to stick is avoided, since the sleeve and valve stem assembly has, as a unit, a much greater length than diameterand, therefore, does not have a tendency to cock and bind in slidingthrough lthe hole in the magnet as did the cylindrical-l armature of the prior art, with diameters greater than their lengths. 4

Referring to Fig. 3, which showsu feeder circuit with the electromagnetic release valve of my invention connected therein, the release valve and cylinder are represented by the numeral 83 and the magnet-valve by the numeral 82. The synchronous converter 69 is supplied with alternating current from a line and one of the output terminals is grounded as is customary in railway feeder circuits. The other terminal leads to. the feeders 'indicated' at the right and the line is protected at various places by the contactors 70, 73, 74, 77 and 78. The contactor 73 fis the one which is -operated 'by'.l my improved electromagnetic vrelease valve and is shunted by the heavy'grid resistances R which substantially reduce the short-circuit current when the contactor 73v is opened, thereby reducing the short-circuit load before feed,-

er'clo'ntactor 77 or 78 can open and thus preventing flash-overs o n the synchronous converter 69. The series coil 64 is'provided with an inductive shunt 72 across which it is connected, the function of whichis tomomentarily cause a large currentv to pass through theY coil 64 when a short-circuit octo demagnetize the core of the elecftromagnet by counteracting the'- magnetic u-x produced by the shunt coil 19. The series coil 63 is= not provided with a sepathe magnet valves 79 and 80 simultaneously rate inductive shunt, but depends upon the with the contactors.

voltage drop through a part of the bus, i. e., Resistances n, land ,T7 are for the same purthe current divides through the series coil pose and function in the same manner as 7*,1'1, 63 and the section of bus and is inversely r4 and rs. f proportioned to their resistances and affords p Although compressed air is generally used a means for adjusting the magnet-valve to for maintaining the piston in the cylinder a predetermined over-load. The numeral in a raised position to. keep the contactor 8,1 indicates the interlock switch which iso closed, it is obvious that any suitable fluid erated simultaneously with the contactor 3 under pressure may be used for the same purto insert a resistance 7' in series with the coil pose.

19 after the contactor is closed, thereby re- :While I have shown only one embodiment ducing thecurrent through the coil 19 s'o of my invention for the purposes of illusthat the magnetic flux produced by it isv retration and description, itwill be apparent duced, vwhich may be more easily opposed to those s lulled in the art that other changes by the magnetic flux from the series coil 64. and modifications may be made Without de- In addition to the resistance r in series with parting from the scope-of the invention. I,

coil 19, there is also a resistance r1 in series therefore, desire to be limited only by the with coil 20 and each resistance r and r1 is scope of the'appended claims.V

shunted bythe interlocks 81 and 84, i. e., the I claim:

interlocks short-circuit the resistances when 1. An electromagnetic release valve adaptthe contactor is open and leave them in cir-l ed for use with a fluid-actuated device comcuit with the coils when the contactor is prising a. valve and valve seat, a spring surclosed. rounding the valve stem for actuating said The circuit of the interlock' switch 34 lis valve, an electromagnet, an armature having also shown and is in series with the shunt coil a sleeve portion extending slidably xthrough 20, so that the coil cannot beenergized until the Core of said magnet and abutting said othe valve of the release valve 83 is closed as Spring, said valve stem extending slidably has been explained hereinbefore. The shunt through said sleeve, and means on the end coils 19 and 20 of the release valve 83 and' of said valve stem for varying the pressure y .magnepvlve 82, respectively, are energized of said sleeve on said spring to impart iniyfrom a control current su ply or control tial compression thereto, said electromagnet circuit as are the coils 86 and 87 of the magbeing adapted to impart nal compression to net-valves 7l and 85.V They control is genersaid spring to actuate said valve. ally provided from a current recti ing device (not shown), at 32 volts an due to ed for use with a fluid-actuated devicelcompoor voltage regulation of the rectifying deprising a valve and valve seat, a spring survice, it was necessary heretofore to employ rounding the valve stem for actuating said a storage battery floating on the control valve, an electromagnet, an armature havcircuit. The use 4of my invention reduces ing a sleeve portion extending slidably the amount of control energy required for through the core of saidimagnet and abutting the substation apparatus to such an extent said spring, said valve stem extending slidthat the storage battery is not necessary, ably through said sleeve, means onthe end of thereby e'iecting a material saving in the said valve stem for carrying the pressure of cost of-maintenance and replacement of such said sleeve on said spring to impart initial batteries at substations. A compression thereto, said electromagnetbeing The series windings 90 and 91 of the magadapted to impart linal compression to said net valves 79 and 8O of the feeder .contactors spring to actuate said valve, and a second 77 and 78 are lprovided with inductive shunts Ispring acting on said sleeve portion to urge 75 and 76 w .are energized from the line through bridgelectromagnet.

.rent flowing thereiirafter thelcontactors 77 ing resistances R1 and R2. In series with 3. A device adapted for use with a fluid'- shunt coils 88 and 89 are adjustable resistactuated device of the type comprising an ances rzand rs, adjusted to enable the shunt electromagnetic valve for controlling the incoils 88 and 89 to overcome theliux due to gress and egress of'lluid, said device compristhe small current' in the series c oils, 90 and 91 ing a/ release valve serving to hasten the .when the short-circuit current is reduced to a egress of air to quicken the action of said 2. 'An electromagnetic release valve adapt` ile' the shunt coils 88 and 89 said armature to Within tractive range of said,

predetermined amount` and thus cause conu'id-actuateddevice, and means for rendertactors 7 and 78 vto reclose. Resistances ing said electromagnetic valve inoperative T4 and 7s are PI'QVidQ/.d lSO in Series 'with until said releasevalve is in its normal posicoils 88 and 89 to ,redu'celthe'amonnt of curltion.

4. A device adapted for use with a fluid- I and 78 are closed. A While the'contactors are actuated device of the type' comprising an open, the resistances are shunted by their re-` electromagnetic valve for controlling the inspective interlocks which are actuated by gress and egress of fluid,\said device comprising a release valve serving to hasten the egress of air to quicken the action of said Huidactuated device and a switch operable by said release valve for rendering said electromagnetic valve inoperative until said release valve.-

is in its closed position. l 5. An electromagnetic release valve adapted for use with a fluid-actuated device for opening and closing an electrical circuit comy prising avalve and valve seat, an electromagnet for actuating said valve, said electromagnet comprising a shunt coil for' energizing the same and a series coil for energizing said magnet in opposition to energization by said shunt coil, said series coil being connected across an inductive shunt in said cir cuit, whereby the armature of said electromagnet may be released in the event of abnormal load current How in said circuit.

l RALPH F. THOMPSON.

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