US2574334A - Air-blast circuit breaker - Google Patents

Description

Nov. 6, 1951 A. LATOUR AIR-BLAST CIRCUIT-BREAKER 5 Sheets-Sheet l Filed July 25, 1947 /1/4 ,WL/WW.

Nov. 6, 1951 A. LATOUR 2,574,334

AIR-BLAST CIRCUIT-BREAK@ Filed July 23, 1947 5 shams-sheet 2 Nov. 6, 1951 A. LATOUR 2,574,334

AIR-BLAST CIRCUIT-BREAKER Filed July 25, 1947 5 Sheets-Sheet 3 Nov. 6, 1951 A. LATOUR 2,574,334

AIR-BLAST CIRCUIT-BREAKER Filed July 23, 1947 5 Sheets-Sheet 4 Nov. 6, 1951 A. LATOUR AIR-BLAST CIRCUIT-BREAKER 5 Shams-Sheet 5 Filed July 23, 1947 INVENTOR. fm/

Patented Nov. 6, 1951 AIR-BLAST CIRCUIT BREAKER Andr Latour, Grenoble, France, assigner to Etablissements Merlin & Gerin, Grenoble,

France Application July 23, 1947, Serial N o. 763,024 In France April 6, 1940 Section 1, Public Law 690, August 8, 1946 Patent expires April 6, 1960 4 Claims.

The present invention relates to gas blast cir cuit breakers, and more particularly to gas blast circuit breakers with a movable hollow contact element and a spring loaded valve arranged coaxially to the movable contact element.

It is an object of the present invention to provide a high voltage circuit breaker in which the steps of interruption and closing are obtained by particularly simple and economical means of construction.

It is another object of the present invention to provide means to improve the action of the circuit breaker and to render its adjustment and upkeep more easy.

According to the present invention the gas blast circuit breaker comprises a chamber arranged at the end of the movable contact element opposite to the contact-making face thereof; an aperture arranged in a wall of the chamber and connecting the same with the atmosphere, said aperture being arranged in the path of the movable contact so as to be closed by the same in the contactbreaking position thereof; a seat for the valve arranged in the wall of the chamber at a distance apart from the aperture; resilient means urging the Valve away from the seat; and openings in said chamber connecting said valve seat to the atmosphere, whereby the valve is closed by the gas blast entering the chamber through the hollow contact element and is opened when the gas blast is cut olf from the chamber by the closing movement of the contact element.

In a preferred embodiment of the present invention a second chamber is arranged at the end of the hollow of a stationary contact element turned away from the contact-making face thereof and is provided with a valve similar to that mentioned hereinabove.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specic embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 shows an axial section of a circuity breaker with a single movable contact.

Fig. 2 shows an axial section of a circuitbreaker with two movable contacts, more especially for very high voltages.

Fig. 3 shows in its upper portion a section along the line Xi-Xz of Fig. 2 and in its lower portion a side elevation taken at right angles to Fig. 2.

CII

Fig. 4 shows an exhaust pot for an outdoor installation.

Fig. 5 shows an assembly of a circuit-breaker and the auxiliary control elements according to the invention and permitting a rapid reclosure.

In Fig. l, I represents a stationary hollow contact element arranged in the form of a nozzle and 2 a movable hollow contact element of tubular shape. The forward orifice 3 of the contact I opens into a chamber ll, called the exhaust chamber, which communicates with the atmosphere through the orifice 5. rIhis orifice can be closed more or less completely by a valve 6, which is normally kept in open position by a spring l. A cylinder 8 formed by one or several layers of fine metal gauze collects the gases leaving the orifice 5 and allows them to lter into a hood 9 only after having suitably cooled them. An aperture or opening ll formed at the lower part of the hood allows the gases to pass freely to the atmosphere. The hood 9 is preferably provided with a contact piece Il on which can rest the contact head I 2 of a disconnecting switch I3.

The movement of the movable contact 2 shown at 2 in open position is effected by a piston I4 sliding in a cylinder I5 and returned by a spring I6 which determines the pressure of contact of the movable contact 2 on the stationary contact I. The front face of the piston I4 can be subjected to the action of compressed gas by means of one or more apertures Il provided in the wall of the cylinder. The rear face of the piston may be subjected, if desired, either to the action of atmospheric pressure or to the action of the compressed gas through the intermediary of a duct I8 connected through an insulating tube 20 to a distributor I9.

The central passage of the movable contact 2 communicates with the atmosphere on the one hand by an orice 2l which may be shut by a Valve 22, kept normally in open position by a spring 23, and on the other hand by one or more orifices 24, which are closed by the movable contact 2 in the opening movement thereof.

The two kinds of orices 2li and 2l open into an exhaust pot 25 protected from weather influences by hoods 26 and 2l. The cylinder I5 bears at its upper end a flange 28 forming a cover fixed to the insulator 3i! by a collar 29. An insulator 35 is, on the other hand ixed to a collar 3| carrying the stationary contact I. The part 32 is an easily replaceable arcing-electrode. The whole is supported by an insulator 33, through the interior of which the compressed gas can be introduced by means of the duct 34, which at the same time feeds the distributor I94 through the pipe 35. Current enters through a terminal and leaves by the disconnecting switch I3, or vice versa.

The operation of this device is as follows:

When the breaker is closed no blast can happen in the chamber 4, or in the movable contact 2, no matter what may be the pressure in the interior of the insulator 30.

Through the intermediary of duct 34 the piston I4 is subjected on the front thereof to the 'pressure of the gas passing through the apertures I1 and on the rear face to atmospheric pressure transmitted by the duct I8, the tube 2G rand the distributor I9 which at this moment is in the position shown on Fig. 1. The piston I4 thus moves upwards, compressing the spring I6, and carries along with it the movable contact 2 into position 2 in which the movable contact closes the orifices 24.

In this position, the compressed gas flows rapidly through the stationary contact I the vexhaust-chamber 4, the orifices 5 and I@ and on the other hand, through the central duct of the movable contact 2, the orifice 2l and the hoods 26 and 21. Thus a very strong blast is produced and the arc formed by the parting of the contacts I and 2 is rapidly extinguished. As soon as the blast occurs the valves and 22 are urged to close, but, these, because of their mass, have not been able to travel their closing distance before the short time necessary to extinguish the arc. When the valves 22 and S are closed, the blast is interrupted and the compressed gas is maintained without appreciable leakage within the insulator 30, thus securing vas long as necessary the breaking of the circuit and the insulation between the contacts.

The final opening of the circuit is secured by theopening of the disconnectingswitch I3.

When this operation is terminated, the interior of the insulator 3i) may vbe brought to atmospheric pressure by a device not shown inthe drawing. Thus the contacts close, the valves reopen and the device is ready for a fresh operation.

1f, on the contrary, leaving the disconnecting' switch I3 in closed position, a closing of the circuit is intended, it su'fces to actuate the distributor I9 in the direction of the arrow 3l.

This may be done by hand, or after a predetermined lapse of time automatically by means of any mechanical, pneumatic. or electric device. Under such conditions, the 'piston I4 is subjected on both faces to the same pressure and may be rapidly moved bythe force of the Ispring I5. Thus, the movable Contact returns 'to its initial position in contact with the stationary contact i, closing thereby the inlet of compressed 'gas into the chamber and vopening the apertures '24 through which the residual compressed gas escapes immediately into the atmosphere. Thereafter the valves 6 and 22 are no llonger subjected to any pressure and are reset by their respective springs.

The device is then ready for a new operation which Vmay be obtained by the reverse movement of the distributor I9 and that as often as required. The distributor I9 could likewise be located on one of the parts under voltage, for instance the flange 28, and actuated pneumatically or mechanically by a device at the interior or exterior of the insulator 30. An example `of such a design will be given hereinafter.

It will be noted that in the closing movement a blast of very short duration is created, as soon as the movable contact 2 has uncovered the apertures 24. This feature involves an advantage because the ionized vapors produced by the closing arc and which may disturb a subsequent break are eliminated.

Another advantage of the described invention resides in the easy accessibility of the contacts. The movable contact and its whole mechanism are easily removable as soon as the cover 28 has been unscrewed from the collar 29. The station ary contact I and the arcing contact 32 are then easily removable by means of a tube Spanner.

Figs. A2 and 3 show another embodiment of the invention more particularly characterized in thatI two breaking elements are used which are identical and the similar to those of 1. The exhaust chamber i and the parts which are following to the chamber in direction of the blast (valve 5 and exhaust pot 3) are single and serve for both breaking elements. The part I, which is in Fig. 1 designed as a stationary contact, is provided in the present case only as a nozzle and made, for instance, of insulating material. The contact is, therefore, achieved by the placing end to end of the two movable contacts 2. Objection may be made that in this position, they do not allow the relief of the chamber 4 from pressure, but in fact, the relief of the pressure in chamber 4 begins as soon as the movable contacts have been entered the necks of the nozzles I, respectively, and by reason of its rapidity, it is generally completed at the moment when the contacts meet each other. Should it be otherwise it would be sufficient to provide grooves on the contacting surfaces of both contacts.

The parts mounted in the interior of the two insulators 3i] joined by the common collar 3| may be supported, without exceeding the scope of the present invention, by a single co-axial in# sulator, as shown in Fig. 1.

However, the device as shown in Figure 2 vis supported through the common collar 3l by an insulator 33 placed at a right angle to the insulators Si) and serving as a duct for the compressed gas. This embodiment of the invention is particularly advantageous because the total height of the breaker is reduced and the accessibility of the contacts and all the parts connected therewith is greatly facilitated.

The two protecting hoods 2l' are arranged at the outer ends of the insulators 3i?, respectively, and the disconnecting switch like the switch I3 Ashown in Fig. 1 is connected to one of these hoods.

This device operates substantially in the same manner as the device shown in Fig. 1.

The distributor Ie is actuated by an insulating push rod 38 actuated b y a cain Se integral with an insulating shaft eil. The rotation of this shaft may be obtained by any means, but preferably by means of an arm Si actuated by a connecting rod 42, driven by a piston 43, which is moved pneumatically in a cylinder 44 against the force of a spring 45 shown in Figs. 3 and 5.

Referring now to Fig. 3 the exhaust takes `place from the upper part of the device, downwards through a cylinder 8 of metallic gauze which the hot gases penetrate in a centripetal direction before reaching the atmosphere. This embodiment prevents the entrance of atmospheric im purities into the breaker. f

A more effective design is shown in Fig. 4 and may be applied to any exhaust device. In this embodiment, the exhaust gases after `having passed through the metallic gauze cylinder 25 lift a hood 21, the rim of which engages the lower portion of a member 25 enclosing the cylinder 25 and provided with apertures for the gas. By the lifting of the hood 21 a spring 4E is compressed, and the exhaust gases escape into the atmosphere. When the exhaust is interrupted, the hood 21 falls back on its seat thus forming a tight protection against atmospheric impurities.

In Fig. 5 a device according to the invention is shown together with the accessories thereof. The interrupting device, as shown for instance in Figs. 2 and 3 is represented by 41. The disconnecting switch I3, is shown in closed position, 49 is a current transformer controlling a tripping relay 50. The breaker 41 is supplied with compressed gas from the reservoir 5i, through a pneumatic valve 52 controlled by an electro-valve 53. A shunt pipe 54 starting at the valve 52 supplies through a duct 55 a device securing a rapid reclosing of the breaker without intervention of the disconnecting switch and on the other hand through a duct 55 the pneumatic control of the disconnecting switch. A cock 51 actuated manually or mechanically allows to eliminate, if desired, the reclosing device. 58 and 59 are pneumatic valves having their opening temporized by calibrated throttles 80 and 6i the cross-sections of which are calculated as functions of the dead space of the cylinders controlling said valves, so that the pressure necessary to actuate these valves is only reached after a predeterminated lapse of time. The dead space situated behind the piston o1 the valve 58 may be brought to atmospheric pressure by the discharge or decompressing valve 62 which opens when a certain pressure exists in the duct 63.

64 is a valve, which, when actuated, closes the supply duct for compressed air 65 and connects the ducts 63 and 55 to atmospheric pressure. In Fig. 5, this valve is represented as an electrovalve closing the gas supply when its electromagnet is energized and maintained energized by the contact 61. It is, however, evident that any other control means such as pneumatic or mechanical ones, may be used.

68 is a manometric device closing a contact 69 when the pressure has become sufficiently strong in the duct 56.

A similar device 16, opens a contact 1I, when actuated by the pressure prevailing in a chamber 13, this pressure being transmitted to the chamber with a convenient delay by a throttle 12.

The operation of the piston 43 has been explained hereinabove in connection with Fig. 2. This piston controls when moving, in the direction of the arrow RE, the rapid reclosing and when moving in the direction of the arrow D the release of the breaker.

The movement of the disconnecting switch I3 is controlled by a piston 14 sliding in a cylinder 15. The opening of the disconnecting switch is obtained by supplying compressed gas to one face of the piston through the valve 58 and the duct 16, and its closing by supplying the compressed gas to the other face of the piston through a closing valve or an electro-valve (not shown). At the end of its opening stroke, this device opens an auxiliary contact 11 and at the end of its closing stroke an auxiliary contact 18, bringing the closing valve into rest position. An auxiliary source 19 supplies low voltage current to the dierent circuits of the arrangement.

As explained hereinabove, the breaker may be 6 utilised as ordinary circuit-breaker or as a circuit-breaker with rapid reclosure.

In the lrst case, the cock 51 is closed, the operation being as follows:

When an excess current occurs on the line 48, the current transformer energizes the relay 50, which closes the contact 8|, which in turn actuates the electro-valve 53, which opens the main valve 52. The contact 52 closes at the same time, but remains inoperative because of the contact 69 which is open. The circuit breaker 41 is set under pressure, the contacts part rapidly, the arc is extinguished, the open contacts close the exhaust orifices, as more fully explained hereinabove. Thus the current is interrupted in the line 48 and the relay 55 opens at once its contacts. The electro-valve 53 remains nevertheless open, because the magnet coil thereof is still energized by current flowing through the maintaining contact 8U. After a certain time, however, predetermined by the retarding throttle 6i), the valve 58 opens and actuates the disconnecting switch which at the end of the stroke thereof opens the contact 11 and cuts the supply of the electro valve 53, so that the latter closes and causes hereby the closing of the main valve 52 and connects the circuit-breaker 4i? and all ducts to atmospheric pressure. I-Iereupon the contacts of the breaker reclose which involves no inconvenience as the disconnecting switch is still open.

In the second case, when the rapidly reclosing ,device is to be used the cock 51 remains open and the operation is the same as in the first case up to the moment when the contacts of the breaker 41 part. But Ias the retardation of the throttle 6I is shorter than the retardation of the throttle 50, the valve 59 opens before the opening of valve 58. The opening of the valve 59 supplies the pressure to the ducts 53 and 55. The pneumatic valve connects through the duct 53 the control chamber of the valve 58 to atmospheric pressure and prevents it from opening as long as the pressure does not disappear in the duct 63. The compressed gas owing through the pipe 56 drives the piston 43 in the direction of the `arrow RE and through rotation of the rod 45 causes the closing of the contacts of the circuit-breaker 41, in a fully compressed gas atmosphere, as has been explained hereinabove in connection with Fig. 2. The effect of this closure is, as already mentoned, the rapid opening of the valves G and 22 (Fig. 2) thus allowing for a subsequent new blast.

If the fault in the line has disappeared, the closing of the contacts of the breaker is not folloWed by any abnormal current and the relay 5!! keeps its own contact open. After a certain time, determined by the throttle i2 supplying the volumetric chamber 13, the manometric device 15 opens the contact 1i. Hereby, the electro-valve 53 and the valve 52 are closed and the arrangement returns to the initial position thereof without any actuation of the disconnecting switch.

If,'however, the fault in the line persists, the closing of the contacts of the 4breaker restores the abnormal current, which then actuates the relay 5D once more.

Thus this relay closes its contacts 8l and 82. The closing of contact 5I has no consequence, the electro-valve being already supplied by its own contact 8U. But the closing of 82 acts on the magnet-coil of the valve 54, because the contact 69 is closed as soon as the duct 66 is under pressure. Thus the electro-valve S4 opens and stays open owing to the current supplied by contact 61. This valve shuts oi the compressed gas www ing of the contacts interrupts the short circuit.

Furthermore the pneumatic valve 62 closes, thus permitting the valve 58 to open after a time predetermined by the throttle E0. The opening of the valve 58 causes the opening of the disconnecting switch I3 which :at the end of the stroke thereof opens the contact 11 and so puts the electro-valves c4 and 53 out of action. By so doing the whole arrangementreturns to its initial position. If the line 48 is to be closed again it suiices to send, by a device not show'n in the drawings, for Vinstance an electro-valve, compressed gas to that face of the piston 14 which "corresponds tothe closing position. The contact 'l1 is reclosed and the breaker is ready for a new operation.

What I claim is:

1. A gas blast circuit breaker with a movable hollow contact element and a spring-loaded valve arranged coaxially to the movable contact element, comprising in combination, a chamber arranged at the end of the movable contact element opposite to the contact making face thereof; an aperture in said chamber for -engagement of-the end or the movable contact `elementopposits to the contact making face thereof; a yseat for the valve arranged in said chamber opposite to said aperture; resilient means urging the valve away from said seat; and .openings in said chambei' connecting said valve seat to the ,-atrnosphere, whereby the valve is closed by the gas -blast entering said chamber through the hollow ,contact `element and is opened when the gas blast vis cut orf from said chamber by the closing movement or" said contact element. Y

2. A gas blast circuit breaker with a movable hollow contact element and a spring-loaded valve .arranged coaxially to the movable contact element, comprising in combination, achamber arranged at the end of the ,movable `Contact element opposite to the contact making face thereof; an aperture in said ,chamber for engagement of the end of themovable contact element opposite tothe contact Vmaking face thereof; a seat for the valve arranged in said .chamber opposite to said aperture; resilient meansurging `the valve away from said seat; openings in `said chamber connecting said valve seat to the atmosphere; orices arranged in the wall of saidmovable hollow contact element; and a stationary duct leading to the atmosphere and adapted to communicate with said orices when the movable contact element is in contact closing position, said orices being closed when the movable contact'element moves into the opening position.

3. A gas blast circuit breaker with astationary hollow contact element; a movable hollow Contact element and two spring-loaded valves arranged, respectively, coaxially to the movablecontact elementand to the hollow of lthe stationary contact element, comprising in combination, a-rstchamber arranged at the end of the :movable contact element opposite to the contact making vface thereof; an aperture in said first chamber for engagement of the end of the movable Contact element opposite to the contact making Yface thereof; a first seat for the valve arranged co.- axially to the movable contact element, said first seat being arranged in said rst chamber opposite to said aperture; openings in said rst chamber connecting said iirst valve seat to the atmosphere; a second chamber arranged at the end of the hollow oi said stationary contact element turned away from the contact making face there-.- of; a second seat for the valve arranged coaxially to the hollow of the stationary Contact element; resilient means urging away the valves from said seats, respectively.; and openings in said second chamber connecting said second seat to the atmosphere, whereby the valves are closed when the gas blast enters said chambers', ,ree spectively, through the movable hollow contact element and the hollow of the stationary contact element and are opened when the gas blast is cut oi by the closing movement of said movable contact element.

1l. A gas blast circuit breaker with a stationary hollow contact element, a movable hollow contact element and two spring-loaded valves arranged, respectively, coaxially to the movable contact element, comprising in combination, a first chamber arranged at the end of the movable contact element opposite tothe contact making Vface thereof an aperture in said rstchamber for engagement of the end of the movable contact element opposite to the contact making face thereof; a first seat for the valve arranged coaxially in the movable contact element, said rst seat'being a1- ranged in said rst chamber opposite to said aperture; openings in said first chamber connecting said first valve seat to the atmosphere; a second chamber arranged at the end of the hollow of said stationary contact element turned away from the contact making face thereof; a second seat for the valve arranged coaXially to the hollow of the stationary Contact element; resilient means urging away the valves from said seats, respectively; openings in said second chamber connecting said second seat to the atmosphere; orifices arranged in the wall of said movable contact element; and a stationary duct leading to the atmosphere and adapted to communicate with said orifices when the movable contact element is in contact closing position, said orifices being closed when the movable contact element moves into the opening position.

ANDR LATOUR.

REFERENCES cifrar) The following references are of record inthe file of this patent:

y UNITED STATES PATENTS Number Name Date 1,645,288 MacNeill Oct. 11, 1927 2,275,885 Bartlett Mar. l0, 1942 2,280,321 Thommen Apr. 21, 1942 2,331,441 ,Thominen et al Oct. 12, 194,3 2,419,446 Flurschem Apr. 22, 1,947 2,440,995 Wilcox Mayl, 1943

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