US2928016A - Lightning arresters - Google Patents

Description

March 8, 1960 F. J. SCHULTZ 2,928,015

LIGHTNING ARRESTERS Filed Aug. 21, 1958 5 Sheets-Sheet l 1 n 26 INVENTOR. 3 A I3 27 Pass J. SCHULTZ F\ Q1. 2 F\ G-l- 3 ATTORNEY March 8, 1960 F. J. SCHULTZ 2,928,016

LIGHTNING ARRESTERS Filed Aug. 21, 1958 3 Sheets-Sheet 2 INVENTOR. FReo J. ScHuL'w;

March 8, 1960 F. J. SCHULTZ 2,928,016

LIGHTNING ARRESTERS Filed Aug. 21, 1958 3 Sheets-Sheet 5 INVENTOR.

v FRED J. SCHULTZ ATTORNEY LIGHTNING ARRESTERS Fred J. Schultz, Milwaukee, Wis, assignor t-o McGraw- Edison Company, Milwaukee, Wis., a corporation of Delaware This invention relates to lightning arresters.

Objects of this invention are to provide an automatically vented, normally sealed lightning arrester.

in lightning arresters as heretofore constructed, it has been the usual practice to provide a ceramic casing with one end open and with this open end sealed by means of a metal plate spun or otherwise secured to the ceramic casing and completely hermetically sealing the casing of the lightning arrester. The effective portions of the arrester were mounted within the sealed casing and usually consisted of a spark gap or spark gaps and valve material connected in series.

In lightning arresters as heretofore constructed when they operate normally under .normallightning surges, the pressure within the lightning arrester casing does not rise to an abnormally high or dangerous value. However, when a very severe stroke is discharged by the lightning arrester or when the lightning arrester becomes damaged from excessive current through it or from any other reason whatsoever, abnormal pressures are frequently generated.

Attempts have been made to overcome these defects by providing a diaphragm which bursts under high pressure, but these attempts have not been wholly satisfactory. The point at which bursting of the diaphragm occurs could not be precisely determined, as the pressures varied widely for slight variations in the thickness, stiffness, and strength of the diaphragm. Further, relatively thin diaphragms had to be used which did not adequately mechanically protect the internally located parts from damage during handling and which, due to their thinness, rapidly reduced in thickness or corroded to apoint where the diaphragms were too frail to adequately perform their functions.

Further objects are to provide an arrester with a relatively thick diaphragm without requiring excessively high internal pressures before venting occurs.

This invention is designed to provide a construction of lightning arrester which is automatically vented when the pressure within the casing rises to a predetermined safe value so that there will not be any danger of exploding the arrester and injuring the lineman or others who have to handle or inspect or replace the arrester.

A further main object of the invention is to provide a lightning arrester which is automatically vented when the internal pressure reaches a certain predetermined point, which normally is hermetically sealed thus protecting the internal apparatus from damage or' from moisture, bugs, or other matter that might enter the arrester nieoi rates Paten if the casing were unsealed, while still maintaining the I in which, when the internal pressure reaches a prede-v termined point, relative motion between the diaphragm and the puncturing member is produced with the result ice that the diaphragm is punctured and the internal gases are vented thus relieving the pressure within the lightning arrester.

, A further specific object is to provide means for puncturing the stressed diaphragm in its center where the stresses are greatest.

In greater detail, objects of this invention are to provide a lightning arrester which has a ceramic or other type of easing open at one end only and which has a plate or diaphragm sealing the open end of the ceramic casing, and which has mounted therein the component parts of the arrester such, for example, as the spark gaps and the valve material connected in series, and in which the diaphragm may be expanded outwardly by the internal pressure, the arrester being also provided with a perforatingmember which may be fixed if desired so that the expanded diaphragm engages the perforating member' and is'perforated or punctured and the pressure vented. This is one form that the invention may take. With various modifications, however, the invention may also take the form in which the diaphragm which is to be perforated, does not necessarily expand outwardly to any material extent, but in which a movable puncturing point is provided and in which means are provided, responsive to internal pressure, which moves the puncturing point towards the diaphragm and punctures the dia phragm.

Embodiments of the invention are shown in the ac companying drawings in which:

Figure 1 is a vertical elevation of one form of the invention with parts in section and parts broken away.

Figure 2 is a fragmentary detail showing a further form of puncturing point.

Figure 3 is a detail showing a still further form of puncturing point.

Figure 4 is a fragmentary view looking upwardly from the bottom of the structure shown in Figure 1.

Figure 5 is a fragmentary sectional view of another embodiment of the invention.

Figure 6 is a fragmentary view looking upwardly from the bottom of the structure shown in Figure 5.

Figure 7 is a sectional view similar to Figure 5 showing a further form that the invention may take.

Figure 8 is a view looking upwardly from the bottom of Figure 7.

Figure 9 is a view corresponding to Figure 5 showing a further form that the invention may take.

Figure 10 is a line section on the line 10, 10 of Figure 9. I

Figure 1 1 is a fragmentary view looking upwardly from the bottom of Figure 9.

It is to be noted that Figures 4, 6, 8, 10 and 11 are drawn to a smaller scale than the remaining figures.

Referring to the drawings, particularly Figures 1 and 4, it will be seen that the lightning arrester comprises a ceramic or other suitable type of casing 1 which is sealed at its upper and lower ends. The upper end is sealed in the usual manner by means of a metallic plate or cap 2 which is spun thereon and holds an insulating packing or bushing 3 tightly against the casing 1. I

The upper end is completed by means of a metallic terminal 4. Cement or other bonding material 5 fills the space between the upper end of the casing 1 and the terminal 4. A spring member 6 electrically connects the cap 2 and the terminal 4. I

The lightning arrester is provided with an alternate series of spark gaps and valve material indicated re spectively at- 7' and 8 and may follow any of the usual constructions. I A

Anyother type of spark gap and valve material could be" employed if desired without, departing from the spirit of this invention since the invention is primarily directed to the lightning arrester haying automatic venting means for venting and thus automatically relieving the internal pressure. The form of spark gap and valve material shown is merely for the purpose of illustration and is in no sense intended to be limiting.

The lower end of the ceramic casing 1 is sealed by means of a metal diaphragm 7 which is spun or other- ..wise secured to the casing I. The usual packing or gasket and support it. The ring 11 also prevents bonding material from flowing into the vent area during assembly. Additionally it is to be noted that leaf springs 12 are employed and electrically connect the diaphragm or plate 7 with the lower terminal 9. The lower terminal 9 is provided with a drain 13 and with a plurality of vents 14. This construction is shown best in Figure 4 in which it will be seen that the vents 14 may be arranged in any suitable manner, for instance as shown in Figure4. The small drain hole 13 is primarily for the purpose of draining any water that might tend to collect in the lower end cap.

While the lightning arrester may be any one of several different types, the one chosen for illustration has a relatively heavy spring 15 at its upper portion which bears against the metallic cap 2. Preferably flexible and extensible braided or other type of connecting loops 16 are positioned around the top and bottom of the spring 15 to connect the upper metal plate 17 of the stack of alternate spark gaps and valve material with the diaphragm or cap 2.

The valve material is indicated at 8' and is received between the successive elements 18 of the spark gaps. The elements 18 of the spark gaps are stamped metal members which are separated by means of high resistance spacing rings 19 in accordance with the usual practice. The top and bottom metal plates are indicated at 17 and 20, respectively.

The lower metal plate 20 rests upon the metallic spacer 21. The metallic spacer 21 is provided with notches 22 and its bottom edge rests upon the diaphragm 7 which may be of stainless steel if desired.

The construction thus far described for the alternate spark gap and valve material assembly is the usual well known type.

The lower plate or sealing diaphragm 7 may be of any suitable material such as stainless steel for example. It is provided with a central cutout portion which is closed by means of a puncturable diaphragm as indicated at 23. This diaphragm may be of lead if desired and when the pressure builds up within the casing or housing 1 beyond a predetermined point, this diaphragm 23 bows downwardly, as shown in the dotted line position, and contacts a perforating or puncturing member or point. The perforating or puncturing member or point 24 may be integral with the bottom conductor or terminal 9 of the form shown in Figure 1. p

The puncturing or perforating member or point 24 need not be an integral part of the lower terminal 9 but can be a separate screw as indicated at 25 in Figure 2 and may be provided with a sharp conical portion 26. This screw is removably screwed into the bottom portion of the lower terminal 9. v i This screw. or puncturing member, whether removable as shown in Figure 2 or permanent or integralas shown in Eigu e 1, need not havea conical .pointbutmay. have aichisel-like point as indicated at 27in. Figure 3 01 may I ha Points 1 a y hape e t The operation of this form of the invention is as follows:

When the pressure reaches a predetermined point, the flexible and expandable diaphragm 23 is bowed downwardly and is forced against the puncturing point 24 and is punctured and allows the pressure within the casing 1 to be relieved before dangerously high pressure is reached.

It is to be distinctly understood that other typesof materials could be used for the diaphragm provided they were expandable and sufficiently flexible to be distended downwardly into contact with the point 24. The diaphragm 23 may be-soldered or otherwise secured in place.

in the form of the invention shown in Figures 5 and 6 substantially the same ideas are employed except that the expandable and puncturable diaphragm may be of rubher or other suitable material and is indicated by the reference character 28 in Figure 5. It is adapted to be perforated or punctured by means of the pointed screw 29. The screw 29 of course may be of any type and may have a perforating point of any suitable shape.

The rubber diaphragm 28 is clamped between a centrally apertured sealing diaphragm 32, which closes the lower open end of the ceramic casing 1, and the centrally apertured pressure or clamping plate 30 and is held clamped by the heavy downward pressure of the spring 31. The plates 30 and 32 may be of stainless steel or of other metal.

, It is to be noted that the lower terminal 33 is provided with an upwardly extending annular supporting ring 34. The ring 34 also prevents bonding material from flowing into the vent area during assembly. Further, it will be seen that the lower sealing diaphragm 32' is provided with depressed portions 35 at intervals within which the conducting springs 36 are positioned. These springs 36 maintain good electrical connections between the bottom diaphragm or plate 32 and the lower terminal 33. The lower terminal 33 is provided with apertures 37 as shown in Figures 5 and 6.

The action of this form of the invention is substantially the same as previously described. When the rubber diaphragm 28 is forced or expanded downwardly, it engages the pointed screw or perforating member and is punctured or perforated and the internal pressure is relieved.

In the form of the invention shown in Figures 7 and 8 it will be seen that the bottom terminal 38 of the lighthing arrester is provided with a central aperture or vent 39. The lower portion of the ceramic casing 1 is sealed by means of the diaphragm 40. The spring 31' is similar to the spring 31 described in connection with Figure 5. The rest of the construction of spark gap, valve material, and high resistance material is the same as that previously described.

The sealing diaphragm or plate 40 may be of stainless steel or other relatively strong material and is electrically connected to the bottom terminal 38 by means of the springs 41 which are seated in indentations 42 in the sealing diaphragm 40. These springs 41 electrically connect the diaphragm 40 with the lower terminal 38.

The lower terminal is provided with a sharp annular cutting edge or perforating edge 43 which is adapted to cut or puncture or perforate the expandable flexible diaphragm 44 which latter may be of lead or of other suitable material.

It is to be noted that when presusre builds up in the casing beyond a predetermined point, that the diaphragm 44 which is secured to the under side of the diaphragm 40 and closes a centrally located aperture in the diaphragm 40, is expandedor forced downwardly and is cut or punctured bytheannular; cutting edge 43 and thus the 7 internal pressure is relieved and the pressure gases are vented through the bottom vent 39 in the lower terminal 38.

In the form of the invention shown in Figures 9, 10 and 11, it will be seen that the diaphragm which seals the bottom of the casing l is indicated by the reference character 45 and is provided with a puncturabie relatively weaker diaphragm 46 which closes a corresponding cutout portion in the diaphragm 45. The diaphragm i is also provided with a diaphragm 47 which is flexible and expandable and may be of lead or any other suitable material. The diaphragms 46 and 4'7 are secured to the dia phragm 45 in any suitable manner as by soldering. in Figure 9 the diaphragms are not shown sectioned as they are too small to show in that manner.

In this form of the invention the spacer is indicated at 48 and corresponds 'to the spacer 21 in the first form of the invention. It has spaced feet or projecting portions 49 which rest in positioning depressions 50 formed in the diaphragm 45.

In this form of the invention the diaphragm 46 is not intended to expand any appreciable distance but instead the puncturing point or perforating member is movable with reference to the diaphragm 46 and is indicated by the reference character 51. It is carried by the relatively long arm of a lever 52 which is pivoted at 53 between upstanding ears 54' which may be formed integrally with the lower terminal 54. The lower terminal 5 is provided with an annular upstanding ring 55 which presses against the diaphragm 45 and is also provided with a venting aperture 56. The ring 55 also prevents bonding material from flowing into the vent area during assembly.

The other end of the lever 52 from that provided with a perforating point 51, is provided with a foot portion 57 which rests against the expandable diaphragm 47 and is pressed downwardly when the internal pressure in the casing 1 reaches a predetermined point. This downward motion of the diaphragm 47 causes an upward motion of the puncturing point 51 which punctures the puncturable diaphragm 46 and allows the pressure gases to escape and thus relieves the pressure within the casing 1. Preferably a spring 58 is provided between the diaphragm 46 and the lever 52 and may be positioned around the puncturing point 51 as shown in Figure 9. v

It will be seen that in each instance means are provided for causing relative motion between a diaphragm and a puncturing member so that diaphragm is punctured when the pressure rises to a predetermined point.

It will be seen therefore that a relatively heavy main diaphragm or sealing diaphragm may be employed for sealing the lower end or the open end of the ceramic casing 1 in each form of the invention, and that this diaphragm is not called upon to expand and burst under predetermined pressure.

It will be seen further that a novel form of lightning arrester has been provided of which several different forms have been illustrated as some of the possible embodiments of the invention though it is to be understood that the invention may take other forms provided there are means for puncturing the flexible diaphragm to relieve the pres sure within the lightning arrester and provided pressure responsive means are incorporated in the structure so as to cause relative motion between the diaphragm and the puncturing member. Further it will be seen that the lightning arrester is so made that dangerous pressures cannot build up within the arrester, but instead after a predetermined pressure is reached the pressure gases are relieved or vented by automatic means responsive to the internal pressure in the lightning arrester casing.

It will be seen further that the structure is relatively simple though it has the essential and necessary features hereinabove set forth in detail.

It is to be understood that the invention in its broadcast aspects comprehends any means in which the puncturing point is either fixed and the diaphragm expanded and caused to bear against the puncturing point, or on the other hand in which the diaphragm does not expand a material distance but in which the puncturing point is moved by means responsive to internal pressure and punctures the diaphragm.

It will be seen that the puncturing of the puncturable diaphragms of the difierent forms of the invention where puncturing is employed, is at the center where the stresses are greatest and where the puncturing will be most effective.

It will be seen further that the device is extremely simple and is easy to produce and may be cheaply manufactured.

It is to be noted that the expressions puncturing and cutting or similar expressions are used synonymously.

The expression puncturable portion is intended to indicate any portion of the plate or diaphragm which is capable of being punctured, perforated or cut, or opened by the puncturing or perforating or cutting member,

whether such portion is an integral part of the plate or diaphragm or a separate part secured to the plate or diaphragm.

Although venting has been shown and described as taking place at the lower end of the arrester, it is obvious that venting could take place at either the upper or lower end of the arrester.

Further, it is to be understood that both ends of the arrester could be vented, as has been shown for one end.

Although the invention has been described in considerable detail it is to be understood that such description is intended as illustrative rather than limiting as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A lighting arrester construction comprising a casing, a flexible diaphragm sealing said casing, puncturing means adjacent said diaphragm, and means responsive to the distension of said diaphragm beyond a predetermined point for causing relative motion between said puncturing means and said diaphragm, whereby said puncturing means punctures said diaphragm upon the generation of abnormal pressure within said casing.

2. A sealed lightning arrester construction comprising a casing, a plate sealing said casing and having a puncturable diaphragm and an expansible diaphragm, a lever pivoted intermediate its ends on said plate and having a puncturing member at one end for puncturing said puncturable diaphragm and having the other end controlled by said expansible diaphragm, whereby when said expansible diaphragm is expanded by internal pressure above a predetermined value, the puncturing member will puncture the puncturable diaphragm and relieve the internal pressure.

References Cited in the file of this patent UNITED STATES PATENTS 2,586,285 Ackermann Feb. 19, 1952 UNITED S'IATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,928,016 March 8 1960 Fred J. Schultz It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 42 for "lighting" read lightning Signed and sealed this 30th day of August 1960 (SEAL) Attest:

ERNEST We SWIDER Attesting Officer ROBERT C. WATSON Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,928,016 March 8 1960 Fred J. Schultz.

ied that error appears in the-printed specification It is hereby certif tent requiring correction and that the said Letters of the above numbered pa Patent should read as corrected below.

Column 6:, line 42 for "lighting" read lightning and sealed this 30th day of August 1960.

Signed (SEAL) Attest:

ROBERT C. WATSON ERNEST W, SW1 DER Attesting Officer Commissioner of Patents

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