US3505487A - Shaped nose section on movable ring valve - Google Patents

Description

April 7, 1970 I D. H. MCKEOUGH 3,505,487

SHAPED NOSE SECTION ON MOVABLE RING VALVE Filed Jan. 25, 1967 4 Sheets-Sheet 1 z 2 I!\ II I V I 2/ 3 April 7, 1970' D. H. M KEOUGH 3,505,487 I SHAPED NOSE SECTION ON MOVABLE RING VALVE Filed Jan. 25, 1967 j 4 Sheets-Sheet 2 April 7, 1970 v D. HqmKi-z gH 3,505,487 I SHAPED NOSE SECTION :ON MOVABLE RINGVALVE;

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SHAPED NOSE SECTION 6N MOVABLE RING VALVE Filed Jan. 25, 1967 4 Sheets-Sheet 4 United States Patent 3,505,487 SHAPED NOSE SECT IQIITI 8N MOVABLE RING V Daniel H. McKeough, Pasadena, Calif., assignor, by

mesne assignments, to I-T-E Imperial Corporation, Philadelphia, Pa., a corporation of Delaware Filed Jan. 25, 1967, Ser. No. 611,600 Int. Cl. H01h 33/82 U.S. Cl. 200-148 2 Claims ABSTRACT OF THE DISCLOSURE An annular blast valve is slidably mounted on the exterior surface of one end of a movable contact. The blast valve engages a seal contained in the interior diameter of a nozzle-shaped stationary contact and slides over a seal ring in the movable contact. The upper end of the blast valve is tapered outwardly so that it does not contact any portion of the movable contact which is above the annular seal ring when the blast valve engages the seal in the stationary contact and the movable contact is closed.

This invention relates to gas blast circuit interrupters, and more specifically relates to an improvement of the gas blast circuit interrupter of copending application Ser.

No. 601,985, filed Dec. 15, 1966, entitled Annular Sliding Valve for Air Blast Circuit Breaker, in the name of John Golota, and assigned to the assignee of the present invention.

In the above noted application, the annular blast valve which directly surrounds the contact region between the movable and the stationary contacts is slidably disposed on the exterior of the movable contact. An annular gasket is carried on this movable contact to provide a high pressure seal between the sliding blast valve and the movable contact.

In the above noted application, the interior diameter portions of the blast valve engage the movable contact surface both above and below the annular gasket. It was found that the sliding blast valve, when arranged in this manner, would sometimes stick on themovable contact so that the operation of the system was not properly timed.

In accordance with the present invention, the upper end of the blast valve is so disposed that when it is in its uppermost position (with the movable contact closed and the blast valve closed) the upper end of the interior surface of the blast valve engaging the movable contact engages the gasket and all portions of the annular blast valve above this engaging region are removed from engagement with any portion of the movable contact above the gasket. In particular, good results were obtained when the interior of the nose of the annular blast valve was curled or cut back. This type of structure was found to eliminate sticking bet-ween the blast valve and the movable contact. Although the reasons for this are not fully understood, it is possible that contaminants coat the surfaces of the movable contact above the gasket and that these contaminants may cause the sticking action.

Accordingly, a primary object of this invention is to improve the operation of an annular blast valve which immediately surrounds the region of contact engagement and disengagement between a pair of cooperating ends.

Another object of this invention is to eliminate sticking of a movable annular valve on the movable contact of an air blast interrupter and to permit smooth valve action.

These and other objects of this invention will become apparent from the following description when taken in connection with the drawings, in which:

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FIGURE 1 is a cross-sectional view of the novel interrupter structure of the invention in the open position.

FIGURE 2 is similar to FIGURE 1 and shows the interrupter structure in its closed position.

FIGURE 3 is a bottom plan view of the stationary contact of FIGURE 1.

FIGURE 4 is a crosssectional view of the upper terminal structure for the interrupter for FIGURES 1 and 2.

FIGURE 5 is a cross-sectional view of FIGURE 1 taken across lines 55 in FIGURE 1.

FIGURE 6 is a partial cross-sectional view of FIG- URE 1 illustrating the method in which the nose of the blast valve is curled outwardly in accordance with the invention.

FIGURE 7 is an enlarged view of the blast valve nose of FIGURE 6.

Referring now to the drawings, the interrupter chamber is comprised of an insulation tube 10 of suitable material which is fitted and sealed in conductive mounting disks 11 and 12 at its upper and lower ends, respectively. Upper disk 11 is then secured to the diskshaped stationary contact 1211, shown in bottom plan view in FIGURE 3. A gas conducting discharge outlet including tube 13 shown in FIGURE 4 is connected atop contact 12a and contains a standard stationary arcing contact finger 14 surrounded by a cooler honeycomb 15, schematically illustrated, which conducts blast gas through openings in terminal plate 16 to the exterior of the interrupter. The bottom disk 12 is then secured to bottom casting 20.

Bottom casting 20 is secured and sealed on the end of a suitable hollow support insulator 21 with a source of high pressure gas, such as air (not shown) connected to the bottom of insulator 21 and thus to central chamber 22 beneath casting 20. Casting 20 has a channel 23 for conducting this high pressure gas through valve seat 24 formed in casting 20. A valve member 25 carried on rod 26 is then movable between valve seat 24 and valve seat 27 which is suitably fastened to bottom casting 20, with valve member 25 normally biased toward engagement with valve seat 27 by the compression spring 28. A suitable operating mechanism (not shown) is connected to rod 26 from some remote position and is responsible for movement of valve 25 as will be later described.

Channel 23 then communicates with channel 28a in bottom casting 20. The upper portion of channel 28a leads into an annular channel 28a surrounding lower conductive member 29 which is secured to casting 20. Conductive member 29 has a flange 30 thereon and concentrically surrounds a cooler honeycomb 31 through which are products and gases may pass to the outlet channel 31a in bottom casting 20 to the external atmosphere.

A movable contact rod 32 having an upper contact section 33 and a lower tail section 34 is then provided with the lower section 34 in sliding relation within member 29 as illustrated. The movable contact rod 32.has

an opening 35 extending therethrough, and is provided with a series of resilient buffer plates such as plates 36, 37 and 38, the bottom plate of which is received by the top of member 29 when the movable contact 32 is in the open position shown in FIGURE 1.

A biasing spring 39 contained between flange 30 of fixed member 29 and flange 40 of the movable contact rod 32 then biases the contact rod 32 upwardly toward the position of FIGURE 2.

Contact rod 32 is in sliding contact engagement with upper conductive cylinder portion 50 of bottom casting 20 by means of a plurality of sliding contacts 51 which surround the contact rod 32. By 'way of example, six such sliding contacts 51 can surround rod 32 as illus- 3 trated in FIGURE 5. Each of contacts 51 are then biased outwardly and into sliding engagement with member 50 as by suitable compression springs 52.

The exterior surface of contact rod 32 is then provided with a shoulder 60 which serves as a stop for annular blast valve member 61 which telescopes over the upper end of contact rod 32. A spring 61a is provided between shoulder 61b on movable contact rod 32 and the interior of valve 61- which biases valve 61 upwardly with respect to contact rod 32. Blast valve member 61 has a lower cylindrical skirt 62 which fits over member 50 with a gas-tight seal formed between members 61 and 50 by the O-ring 67. A second seal is formed between member '61 and contact rod 32 by the O-ring 68.

Annular valve 61 is then movable from the lower open position of FIGURE 1 to the valve closed position of FIGURE 2 where the outer surface annular valve 61 seats against O-ring 69 carried in the stationary contact 12a.

It is to be noted that movable contact rod 32 is movable independently of valve '61 to the disengaged position (from the position of FIGURE 2 to the position of FIG- URE 1), and that when the contact 32 engages stationary contact 12a, it engages on a radially inwardly directed portion 70 of the inverted S-shaped engaging surface of stationary contact 12a.

An annular cavity 80 is then provided within skirt 62 which is connected to channel 28a to permit compressed gas from cavity 22 to fill cavity 80. Channel 22 is connected to main annular chamber 81 formed between the interior of tube and the exterior of extension 50 by virtue of the spider type construction of casting as illustrated by dotted lines in FIGURES 1 and 2. Note that channel 28a and chamber 81 are in communication with one another only when valve is in the position show in FIGURES 1 and 2, through the common channels 23 and 28. When valve 25 moves down (and seats on valve seat 24), channel 28a and chamber 81 are isolated by valve 25.

The operation of the intrrupter of FIGURES 1 and 2 is as follows:

With the circuit interrupter in the closed position of FIGURE 2, compressed air is admitted through chamber 2 through conduits 23 and 28, the valve 25 being in its upper postion where it seats against valve seat 27. The pressure from chamber 28 is then applied under flange 40 of movable contact 52 to aid spring 39 in closing contact rod 32, and to the interior volume 80 under valve 61 to aid spring 61a to close the valve 61, thereby to bias both valve 61 and contact 32 to the engaged position in FIGURE 2. The valve 61 seats on ring '69, thereby to prevent compressed air in chamber 81 from escaping through the center of contact 12a or through channel 35 in contact rod 32.

In order to open the circuit interrupter, the valve 25 is remotely actuated through a suitable operating mechanism which is unimportant for purposes of the present invention, whereby the valve 25 is moved down to seat against valve seat 24. This then vents chamber 28a to the external atmosphere, thereby permitting the pressure beneath the annular valve 61 to fall ofl? rapidly. The valve 61 is so proportioned that the area under the valve within chamber 80 is less than the area at the top of the valve exposed to the pressure within the outer chamber 81, thereby tending to move the valve toward its lower or open position against the force of spring 61a. Moreover, 'when the pressure has fallen sufficiently to allow the valve to move downwardly and break the seal at gasket 69, the area on top of the valve subject to the higher chamber pressure will now be equivalent to the full area of the valve including the area which was internal of seal 69 which was exposed only to external pressure. This sudden increase in area and resultant multiplication of opening force will then drive valve 61 rapidly down against shoulder 60 of movable contact 32 and independen ly of movement of movable contact 62.

When the valve 25 vents chamber 28a, pressure under flange 40 of movable contact rod 32 was also removed. However, the force of spring 39 is still sufficient to hold contact rod 32 in engagement with stationary contact 12a. As soon as valve '61 leaves seal 69, however, the entire upper surface of contact 32 is exposed to the high pressure of chamber 81 which is sufiicient to move contact rod 32 rapidly downward against the force of spring 39.

Consequently, in operation, valve 61 is initially unsealed from seal '69 whereupon it immediately moves downward, independently of contact 32, with a popping type action once the remainder of its internal area within seal 69 is exposed. Similarly, the movable contact is exposed to high operating pressure immediately after valve '69 is opened whereupon contact 32 also moves down with a popping action. Since valve 69 opens immediately prior to separation of contacts 32 and 12a, a strong air blast will be established between the separating contacts to extinguish any are drawn therebetween. This air blast is then conducted through the cooler honeycomb 15 (FIGURE 4) to external atmosphere, and through central opening 35 and through honeycomb 31 to external atmosphere. Note further that there is no delay in application of blast air to the contact after the blast valve is opened since this air (and the blast valve), surrounds the contact area and need not be conducted through auxiliary channels. Thus, air blast need continue only long enough to extinguish the arc whereby compressed air of the supply is conserved. Moreover, the air pressure at the contacts has the same pressure as the supply source (as measured in cavity 22), and it is not necessary to increase the air supply pressure to account for pressure drops in conduits leading from the blast valve to the contact.

In order to shut off the blast of air and reset the contacts, the operating mechanism moving valve 25 is suitably arranged so that the valve 25 is automatically returned to the position shown in the drawings where the valve 25 seats against valve seat 27. This action will permit compressed air to enter channel 28:: and chamber 80, thereby moving the valve 61 upwardly to seal against O-ring 69 with a snap action. The closing of valve 61 removes the pressure from the top of contact 32 whereby the pressure beneath flange 40 and spring 39 will move contact 32 toward its engaged position 'with a subsequent snap action.

Note that a supplemental isolating contact means (not shown) will be connected in series with the interrupter contacts in the usual manner. This interrupter is synchronized with the operation of valve 25 to establish an open circuit to prevent the reclosing of contact 32 from reestablishing the circuit which has been opened.

It is to be particularly noted that the air pressure within the movable contact chamber acts independently on both contact 32 and annular valve 61. In this manner, the 'contact force is made independent of the sealing force and adds to the force obtained from the main closing spring 39. This results in high contact pressure between contacts 32 and 12a up to the instant of contact separation. At the same time, the force under annular valve 61 is proportionally lower so as to not develop excessive sealing pressure, thereby allowing the valve to be of light construction so that it will be rapidly movable under the differential pressures applied thereto during opening.

Referring now to FIGURES 6- and 7, components similar to the components of FIGURES 1 through 5 have been given similar identifying numerals.

FIGURES 6 and 7 illustrate the improvement of the invention wherein the-nose of blast valve 61 has been cut back or curled outwardly as at region 101 so that when the blast valve 61- is in its uppermost position and contact 32 is in its uppermost position, the interior diameter 103 at its uppermost region of blast valve 61 engages some portion of gasket 68. In this manner, the interior portion 103 of valve 61 is removed from the exterior conductive surface 104 of the movable contact 32 which is disposed above gasket 68. It has been found that when this type arrangement is used that a smooth sliding action will be obtained between valve 103 and contact 32 at least during the initial opening operation of the interrupter when the valve 61 must initially move downwardly with respect to contact 32 to break the seal of gasket 69.

Although this invention has been described with respect to its preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred, therefore, that the scope of the invention be limited not by the specific disclosure herein.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A gas blast circuit breaker comprising, in combination: a stationary contact, an elongated movable contact movable between an engaged and disengaged position with respect to said stationary contact; an annular blast valve surrounding said elongated movable contact; said annular blast valve having an interior surface portion extending along a major portion of the axis thereof; said interior surface portion engaging and being axially slidably movable over the exterior surface of said movable contact; said annular blast valve having first and second opposite annular surfaces facing respectively toward and away from said stationary contact; a first chamber in communication with said second annular surface of said blast valve; a high pressure gas source; valve means for selectively connecting said first chamber to said high pressure source or to a low pressure exhaust region respectively; a second chamber connected to said high pressure gas source; said movable contact and said annular blast valve contained within said second chamber; an opening in said second chamber adjacent one end of said elongated movable contact and in the region where said movable contact engages said stationary contact; seal ring means disposed in said opening and engageable by an exterior annular region on said first annular surface of said annular blast valve; said opening in said second chamber communicating with a low pressure region; said end of said movable contact exposed to said low pressure region when said first annular surface of said annular blast valve engages said seal ring means and said movable contact engages said stationary contact; connection of said first chamber to said low pressure region by said valve means permitting the release of said first annular surface of said annular blast valve from said seal ring means whereby high pressure from said second chamber is connected over the full surface area of said first annular surface of said blast valve to move said blast valve down along said movable contact and said high pressure source is connected over the end surfce of said movable contact, thereby to move said movable contact down and away from said stationary contact with the opening of said blast valve permitting a blast of high pressure gas through the region between the separating movable and stationary contacts; and annular gasket means surrounding the outer diameter of said movable contact and engaging the interior diameter surface of said blast valve; the improvement which comprises the positioning of said annular gasket axially along said elongated movable contact whereby the top end of said interior diameter surface of said blast valve engages said movable contact outer diameter, and is adjacent said first annular surface engaging said annular gasket means, and falls short of engagement with the conductive movable contact material above said annular gasket when said movable contact is engaged with said stationary contact and said blast valve is in its sealed and uppermost position with respect to said elongated movable contact.

2. The device as set forth in claim 1 wherein said end of said interior diameter of said blast valve has an outwardly curled region to remove uppermost regions of said blast valve from contact with regions of said movable contact above said annular gasket.

ROBERT S. MACON, Primary Examiner

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