AU2016201372A1 - Flameproof Electrical Connector - Google Patents

Abstract

H:\evk\Interwoven\NRPortbl\DCC\EVK\9661979_1.docx-24/10/2011 - 17 The present invention provides a flameproof electrical connector, including a) a body for housing one or more electrical contacts; b) a fixed flange extending radially outward from the body proximate a first end of the body; and c) a removable flange securable to the fixed flange, the removable flange having a first surface configured to form part of at least one flameproof path when the connector is coupled to a mating connector. Fig. 1A 0) C'4 C)o

Description

FLAMEPROOF ELECTRICAL CONNECTOR

Priority Documents [0001] The present application claims priority from Australian Provisional Application No. 2015900742 titled "FLAMEPROOF ELECTRICAL CONNECTOR" and filed on 3 March 2015, the content of which is hereby incorporated by reference in its entirety.

Background of the Invention [0002] The present invention relates to flameproof electrical connectors. In a particular form, the invention relates to flange mounted cable couplers and adaptors used in hazardous underground environments such as coal mines.

Description of the Prior Art [0003] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

[0004] Electrical connectors such as cable couplers or adaptors are used extensively in mining to couple lengths of cable together or to connect cables to electrical switchgear or other equipment. These types of connectors are therefore used to deliver power to areas of the mine site including both above ground and underground.

[0005] Electrical connectors such as bolted cable couplers and adaptors are often used in hazardous environments such as in underground mines which may contain an explosive atmosphere, for example containing firedamp which is a flammable gas found especially in coal mines and coal dust. Electrical connectors and other electrical enclosures used in such environments are required by relevant standards (e.g. IEC60079 Part 1 and 2) to be flameproof (or explosion proof) in order to minimise the risk of a potentially dangerous explosion or fire occurring in the underground mine.

[0006] Flameproof electrical connectors and enclosures more generally are designed to withstand an internal explosion and prevent the ignition of any flammable gases in the surrounding atmosphere due to sparks, flashes or the internal explosion. Such connectors are designed to have a flamepath where corresponding surfaces of two parts of an enclosure or connector come together to prevent the transmission of an internal explosion to the surrounding atmosphere.

[0007] Flameproof bolted electrical cable couplers and adaptors are typically flange mounted. Each coupler or adaptor typically has a body which terminates in a mounting flange that bolts to a mounting flange of a mating coupler or adaptor. The mounting flanges of each coupler or adaptor provide corresponding surfaces which are bolted together to form one or more flamepaths, the design of which is governed by the above mentioned standards for explosion proof equipment. The flameproof flanges of each coupler or adaptor have specified dimensions and when assembled together a maximum allowable gap is defined between the flanges (which may permit some gases to be exhausted from the enclosure and appropriately cooled before propagating into the surrounding atmosphere). The surfaces of the flanges are also machined to a specified surface finish so that they are sufficiently smooth to function as a flameproof path.

[0008] If any damage occurs to the flameproof flanges in the form of divots, gouges or scratches, the flanges will typically no longer be within tolerance and suitable for use as a flamepath. Such damage occurs often due to handling and incorrect methods of closing and opening the couplers and adaptors when assembled together. If any damage is identified, the coupler or adaptor must be replaced in its entirety. It is removed from the underground environment and taken by vehicle to a service centre whereby the damaged coupler or adaptor is cut off of the cable and a new coupler or adaptor is fitted. The damaged coupler or adaptor is scrapped as the flameproof flange cannot be repaired once it is damaged.

[0009] Damage to flameproof flanges of bolted cable couplers and adaptors is therefore very costly to mine operators due to coupler and equipment downtime whilst the coupler is offsite, and the cost of purchasing a new coupler or adaptor to replace the damaged one. It is estimated that the cost of replacing a damaged coupler or adaptor may currently be around AUD$ 10,000 to $15,000.

[0010] It is against this background, and the problems and difficulties associated therewith, that the present invention has been developed.

Summary of the Present Invention [0011] In one broad form the present invention seeks to provide a flameproof electrical connector, including: a) a body for housing one or more electrical contacts; b) a fixed flange extending radially outward from the body proximate a first end of the body; and, c) a removable flange securable to the fixed flange, the removable flange having a first surface configured to form part of at least one flameproof path when the connector is coupled to a mating connector.

[0012] Typically the removable flange is substantially annular.

[0013] Typically the removable flange includes a second surface contactable with the fixed flange and wherein the removable flange includes a plurality of blind holes that extend from the second surface towards the first surface.

[0014] Typically a plurality of fasteners extend from the rear of the fixed flange into the blind holes of the removable flange to thereby secure the removable flange to the fixed flange.

[0015] Typically a plurality of circumferentially spaced apart lugs extend from an outer periphery of the removable flange so as to be disposed outside of any flameproof path.

[0016] Typically each lug includes a blind hole receivable of a fastener that extends from a rear surface of a corresponding lug on the fixed flange to thereby secure the removable flange to the fixed flange.

[0017] Typically the removable flange includes a plurality of radially spaced apart through holes configured to receive fasteners that extend through corresponding through holes of the fixed flange, said fasteners for coupling the connector to a mating connector.

[0018] Typically the first end of the body includes a lip which axially extends forward from an inner periphery of the fixed flange.

[0019] Typically a portion of the removable flange is seated on the lip to thereby locate the removable flange onto the fixed flange.

[0020] Typically the connector is a cable coupler or adaptor.

[0021] Typically the connector is used in an underground mine.

[0022] Typically the removable flange is made from at least one of: a) stainless steel; b) brass; or c) bronze.

[0023] Typically the interface between the second surface of the removable flange and the fixed flange forms at least one further flameproof path.

[0024] In another broad form the present invention seeks to provide a flameproof electrical assembly, including: a) a first electrical connector, including: i) a body for housing one or more electrical contacts; ii) a fixed flange extending radially outward from the body proximate a first end of the body; and iii) a removable flange secured to the fixed flange, and b) a second electrical connector, including: i) a body for housing one or more electrical contacts; ii) a fixed flange extending radially outward from the body proximate a first end of the body; and iii) a removable flange secured to the fixed flange, wherein, the first and second electrical connectors are assembled by mounting the removable flanges of each connector together so as to form a flanged joint that provides at least one flameproof path.

[0025] Typically the one or more electrical contacts or each connector make electrical contact through mutual engagement with one or more intermediate double sided contacts disposed between the first and second electrical connector.

[0026] Typically the one or more electrical contacts of each connector are: a) all male; or b) all female.

[0027] Typically the doubled sided contact is: a) female; or b) male.

[0028] In another broad form the present invention seeks to provide a removable flameproof flange for an electrical connector, including: a) a substantially annular body having a first surface spaced apart from a second surface; b) a plurality of radially spaced apart through holes that extend between the first and second surfaces; c) a plurality of radially spaced apart blind holes that extend from the second surface towards the first surface, the blind holes radially offset from the through holes, wherein, in use, the blind holes receive fasteners used to secure the removable flange to a fixed flange extending radially outward from a body of the connector proximate a first end thereof and the through holes receive fasteners used to couple the connector to a mating connector such that the first surface of the annular body forms part of at least one flameproof path.

Brief Description of the Drawings [0029] An example of the present invention will now be described with reference to the accompanying drawings, in which: - [0030] Figure 1A is a partially exploded perspective view of an example of a flameproof electrical connector fitted to an electrical cable; [0031] Figure IB is a side view of the connector of Figure 1A; [0032] Figure 2 is a fully exploded perspective view of the connector of Figure 1A; [0033] Figure 3 is an assembled perspective view of the connector of Figure 1A; [0034] Figure 4 is a partially exploded perspective view of an example of a flameproof electrical assembly; [0035] Figure 5 is a partial side view of the flameproof electrical assembly shown in an assembled configuration; [0036] Figure 6A is a front view of the flameproof electrical connector shown in Figure 3; [0037] Figure 6B is a detailed cross sectional view taken along section A-A of Figure 6A for a flameproof electrical assembly; [0038] Figure 6C is a detailed cross sectional view taken along section B-B of Figure 6A for a flameproof electrical assembly; [0039] Figure 7 is a cross sectional view of the flameproof electrical assembly shown in Figure 4 (showing the flange joint between mating connectors); [0040] Figure 8 is a fully exploded perspective view of another example of a flameproof electrical connector; and [0041] Figure 9 is a cross sectional view of another example of a flameproof electrical assembly between connectors of the type shown in Figure 8 (showing the flange joint between mating connectors).

Detailed Description of the Preferred Embodiments [0042] An example of a flameproof electrical connector 100 will now be described with reference to Figures 1A to IB.

[0043] In this example, the flameproof electrical connector 100 is fitted onto the end of a length of electrical cable 10 (e.g. a three phase electrical power cable carrying between 660V to 35kV). Accordingly, this type of connector 100 may be used to couple lengths of cable together and may be referred to as a cable coupler. Alternatively, the connector 100 may be fitted to switchgear or other electrical equipment in which case it may be referred to as an adaptor to which a cable coupler may be attached (for example to connector a cable to a piece of electrical equipment).

[0044] The connector 100 includes a body 110 for housing one or more electrical contacts 130. The electrical contacts 130 shown in this example are male (i.e. pins), however in other examples the contacts could be female (i.e. socket contacts). The connector 100 shown is a three phase connector for delivering three phase electrical power, however the connector 100 is not limited to this and the number of electrical contacts may vary accordingly. The contacts 130 are typically located within insulators 132 which assist in providing phase segregation in order to reduce the likelihood of phase to phase faults occurring.

[0045] The connector 100 includes a fixed flange 120 extending radially outward from the body 110 proximate a first end of the body 110. A removable flange 150 is securable to the fixed flange 120, the removable flange 150 having a first surface 152 configured to form part of at least one flameproof path when the connector 100 is coupled to a mating connector (see Figures 4 and 5 for example).

[0046] In this way, if the first surface 152 of the removable flange 150 is damaged in any way (e.g. scratched, gouged, dented or otherwise put out of tolerance with the relevant standards that regulate the design of flameproof enclosures) rendering it unsuitable for use as a flameproof flange, the removable flange 150 can simply be removed from the connector 100 and replaced with a new removable flange. This repair can be performed in-situ in the underground mine for example and does not require the connector 100 to be taken above ground for repair. Replacing the flange also does not interfere with any of the electrical contacts or insulators. Furthermore, instead of needing to replace the entire connector if a flameproof flange is damaged as occurs with prior art bolted couplers and adaptors, the above described connector only requires the removable flange to be replaced which may cost as little as AUD$50-$200. The above described arrangement therefore enables a significant cost saving when damage to a flameproof flange occurs as well as ensuring that connector (and equipment) downtime is minimised.

[0047] A number of further features will now be described.

[0048] Referring again to Figures 1A and IB, the removable flange 150 is shown to be substantially annular or ring-shaped. Generally, it has a complementary profile with the shape of the fixed mounting flange 120 of the connector 100 to which it is secured. The removable flange 150 may be made from any suitable flameproof material in accordance with the respective standards which may include for example stainless steel, brass or bronze.

[0049] As shown in Figure IB, the removable flange 150 includes a second surface 154 contactable with the fixed flange 120. When assembled, the second surface 154 of the removable flange 150 generally abuts outer surface 122 of the fixed flange 120. The fixed flange 120 includes a plurality of through holes 124 that correspond with a plurality of blind holes (not shown) that extend from the second surface 154 of the removable flange 150 towards the first surface 152.

[0050] A plurality of fasteners 140 extend from the rear of the fixed flange 120 into the blind holes of the removable flange 150 to thereby secure the removable flange 150 to the fixed flange 120. In the example shown, four fasteners 140 (e.g. screws, bolts) are used to secure the removable flange 150 to the fixed flange 120, however any suitable number of fasteners may be used.

[0051] The removable flange 150 further includes a plurality of radially spaced apart through holes 156 configured to receive fasteners (not shown) that extend through corresponding through holes 126 of the fixed flange 120. These fasteners are for coupling the connector 100 to a mating connector, as will be described in more detail below.

[0052] Now referring to Figure 2, there is shown an exploded view of an example of a flameproof electrical connector 100 with a corresponding assembled view shown in Figure 3. The connector 100 includes a body 110 including a fixed flange 120 as previously described located proximate a first end 111 thereof. The first end 111 of the body 110 further includes a lip 115 which axially extends forward from an inner periphery of the fixed flange 120. In use, a portion of the removable flange 150 is seated on the lip 115 to thereby locate the removable flange 150 onto the fixed flange 120.

[0053] A plurality of openings 112 are formed in the body 110 of the connector 100. The openings 112 are configured to receive the one or more electrical contacts 130 and insulators 132 therein. This provides further phase segregation. The insulators 132 are retained relative to the body 110 by a retaining ring 136 which sits over the end of the insulators 132 and is fastened to the first end 111 of the body 110. A sealing ring 134 is retained at least partially between the retaining ring 136 and the first end 111 of the body 110. The sealing ring 134 further presents a sealing face located proximate an end face of the retaining ring 136.

[0054] When the connector 100 is assembled, the outermost surface of the sealing ring 134 is aligned with the edge of lip 115. Accordingly, the removable flange 150 may be located onto the outermost surface of the sealing ring 134 in addition to the lip 115 during installation.

[0055] As shown in Figure 2, the connector 110 may further includes alignment or guide pins 160 which engage with holes 127 located in eyelets or lugs 123 which project outward from fixed flange 120 and are circumferentially spaced apart. The guide pins 160 locate into corresponding holes in the fixed flange of a mating connector to assist in coupling a pair of connectors together.

[0056] In use, a pair of connectors are coupled together to form a flameproof electrical assembly 400 as shown in Figures 4 and 5. For example, a first connector 100 as previously described may be flange mounted to a second connector 200. Connectors 100 and 200 will typically be exactly the same. In other words, both connectors 100 and 200 will typically have all male or all female electrical contacts. In the example shown, connectors 100 and 200 both have a plurality of male pin contacts. As the connectors 100 and 200 are brought into engagement the one or more electrical contacts of each connector 100, 200 make electrical contact through mutual engagement with one or more intermediate double sided contacts 430 disposed between the first and second electrical connectors 100, 200. In the example shown, the double sided contacts 430 are female. In other examples, the doubled sided contacts could be male and the electrical contacts of the first and second connectors could all be female.

[0057] As shown in Figure 5, the flameproof electrical assembly 400 of the first and second connectors 100, 200 is complete when the removable flanges 150, 250 of each connector are fastened together in an abutting relationship. In this way, the first and second electrical connectors 100, 200 are assembled by mounting the removable flanges 150, 250 of each connector together so as to form a flanged joint that provides at least one flameproof path as will be described further with reference to Figures 6A to 6C.

[0058] Figure 6B shows a cross section of an example of a plurality of flameproof paths (flamepaths) 413, 415 and 417 formed when the first and second electrical connectors 100, 200 are coupled together. Flame proof path 415 is formed between the first surface of the removable flange 150 and the corresponding first surface of the removable flange 250 and is defined with respect to the distance between an inner periphery of a respective removable flange 150, 250 to an edge of a respective through hole 156, 256 as shown for example as T in Figure 6A.

[0059] Additional flame proof paths 413, 417 are formed between the respective second surfaces of each removable flange 150, 250 and the respective outer surfaces of the fixed flanges 120, 220. Flame proof paths 413, 417 are also defined with respect to the distance between an inner periphery of a respective removable flange to an edge of a respective through hole 156, 256. In this way, the interface between the second surface of each removable flange and the outer surface of each fixed flange forms at least one further flameproof path for the electrical assembly.

[0060] Referring to Figure 6C, further flame proof paths 412, 414, 416 are defined with respect to the width of the respective removable flanges 150, 250 (distance from an inner periphery to an outer periphery and represented by 'L' in Figure 6A). Flame proof path 412 is formed between the first surface of the removable flange 150 and the corresponding first surface of the removable flange 250. Additional flame proof paths 414, 416 are formed between the respective second surfaces of each removable flange 150, 250 and the respective outer surfaces of the fixed flanges 120, 220.

[0061] These respective flameproof paths prevent the transmission of a spark, flame or internal explosion from escaping the electrical assembly 400 and reaching the surrounding atmosphere.

[0062] The electrical assembly 400 is shown in further detail in Figure 7 which provides a cross section of the flanged joint and electrical interconnection between the first and second connectors 100, 200. When assembled, the respective conductive pins 130, 230 are clamped in the double sided female contacts 430. In this view, fasteners 140, 240 are shown in an assembled configuration extending from the respective rear sides of fixed flanges 120, 220 into blind holes of removable flanges 150, 250. In this way, fasteners 140, 240 enter into flame proof paths 414, 416.

[0063] Fasteners (e.g. mounting bolts) 410 are used to bolt the connectors 100, 200 together through all flanges 120, 150, 250 and 220. The fasteners 410 extend through holes 126, 156, 256 and 226 of the respective flanges and are retained by suitable nuts 420. In other examples, alternative coupling arrangements may be used including for example latch arrangements or other forms of releasable coupling. In order to disassemble the connectors 100, 200, the fasteners 410 are undone and a screwdriver or other suitable device is typically then levered beneath hooks 128 (see Figure 6A for example) to loosen the electrical interconnection and separate the connectors from the double sided contacts 430.

[0064] Whilst in the previous example, fasteners 140, 240 enter into flame proof paths 414, 416 in order to secure the removable flanges to the fixed flanges, other mounting arrangements may be used. An example of an alternative removable flange design and mounting arrangement shall now be described with reference to Figures 8 and 9. For the purpose of clarity, corresponding features that have previously been described with respect to connector 100 shall largely not be described again but it is to be appreciated that these features function and operate together as previously described.

[0065] In this example, an electrical connector 800 is provided that includes a removable flameproof flange 850 that is substantially annular in shape. However, in this example, the removable flange 850 further includes a plurality of circumferentially spaced apart lugs or protrusions 855 that extend from an outer periphery of the removable flange 850 so as to be disposed outside of any flameproof path formed when the connector 800 is coupled to a mating connector.

[0066] Each lug 855 includes a blind hole (see Figure 9) receivable of a fastener 840 that extends from a rear surface of a corresponding lug 823 on the fixed flange 820 to thereby secure the removable flange 850 to the fixed flange 820. When the removable flange 850 is secured to the fixed flange 820 in this way, the securing fasteners 840 do not enter into any flameproof paths.

[0067] The lugs 855 further include holes 857 which align with corresponding holes 827 located on the fixed flange 820. Holes 857 and 827 are for receiving guide or alignment pins used when coupling the connector 800 to a mating connector as previously described.

[0068] A flameproof electrical assembly 1000 formed between first and second electrical connectors 800, 900 is shown in Figure 9 which provides a cross section of the flanged joint and electrical interconnection between the first and second connectors 800, 900. When assembled, the respective conductive pins 830, 930 are clamped in double sided female contacts 1030 which are disposed between the first and second electrical connectors 800, 900. In this view, fasteners 840, 940 are shown in an assembled configuration extending from the respective rear sides of fixed flanges 820, 920 into the blind holes of removable flanges 850, 950. In this way, fasteners 840, 940 are disposed outside of any of the flameproof paths.

[0069] The electrical connectors 800, 900 are coupled together as previously described with respect to connectors 100, 200. Fasteners (e.g. mounting bolts) 1010 are used to bolt the connectors 800, 900 together through all flanges 820, 850, 950 and 920. The fasteners 1010 extend through holes 826, 856, 956 and 926 of the respective flanges and are retained by suitable nuts 1020. In other examples, alternative coupling arrangements may be used including for example latch arrangements or other forms of releasable coupling.

[0070] According to the above described arrangements, there is provided a flameproof electrical connector that can be easily and cost effectively repaired should damage occur to the flameproof flange. The arrangement is advantageous over the prior art as a single damaged flange can be removed and replaced without requiring the connector to be taken above ground and replaced in its entirety as is presently the case which is costly and time consuming.

[0071] Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

[0072] Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.

Claims (18)

1. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1) A flameproof electrical connector, including: a) a body for housing one or more electrical contacts; b) a fixed flange extending radially outward from the body proximate a first end of the body; and c) a removable flange securable to the fixed flange, the removable flange having a first surface configured to form part of at least one flameproof path when the connector is coupled to a mating connector.
2. 2) A connector according to claim 1, wherein the removable flange is substantially annular.
3. 3) A connector according to claim 1 or claim 2, wherein the removable flange includes a second surface contactable with the fixed flange and wherein the removable flange includes a plurality of blind holes that extend from the second surface towards the first surface.
4. 4) A connector according to claim 3 wherein a plurality of fasteners extend from the rear of the fixed flange into the blind holes of the removable flange to thereby secure the removable flange to the fixed flange.
5. 5) A connector according to claim 2, wherein a plurality of circumferentially spaced apart lugs extend from an outer periphery of the removable flange so as to be disposed outside of any flameproof path.
6. 6) A connector according to claim 5 wherein each lug includes a blind hole receivable of a fastener that extends from a rear surface of a corresponding lug on the fixed flange to thereby secure the removable flange to the fixed flange.
7. 7) A connector according to any one of the preceding claims wherein the removable flange includes a plurality of radially spaced apart through holes configured to receive fasteners that extend through corresponding through holes of the fixed flange, said fasteners for coupling the connector to a mating connector.
8. 8) A connector according to any one of the preceding claims wherein the first end of the body includes a lip which axially extends forward from an inner periphery of the fixed flange.
9. 9) A connector according to claim 8, wherein a portion of the removable flange is seated on the lip to thereby locate the removable flange onto the fixed flange.
10. 10) A connector according to any one of the preceding claims wherein the connector is a cable coupler or adaptor.
11. 11) A connector according to any one of the preceding claims wherein the connector is used in an underground mine.
12. 12) A connector according to any one of the preceding claims wherein the removable flange is made from at least one of: a) stainless steel; b) brass; or c) bronze.
13. 13) A connector according to claim 3, wherein the interface between the second surface of the removable flange and the fixed flange forms at least one further flameproof path.
14. 14) A flameproof electrical assembly, including: a) a first electrical connector, including: i) a body for housing one or more electrical contacts; ii) a fixed flange extending radially outward from the body proximate a first end of the body; and iii) a removable flange secured to the fixed flange, and b) a second electrical connector, including: i) a body for housing one or more electrical contacts; ii) a fixed flange extending radially outward from the body proximate a first end of the body; and iii) a removable flange secured to the fixed flange, wherein, the first and second electrical connectors are assembled by mounting the removable flanges of each connector together so as to form a flanged joint that provides at least one flameproof path.
15. 15) An electrical assembly according to claim 14, wherein the one or more electrical contacts or each connector make electrical contact through mutual engagement with one or more intermediate double sided contacts disposed between the first and second electrical connector.
16. 16) An electrical assembly according to claim 15, wherein the one or more electrical contacts of each connector are: a) all male; or b) all female.
17. 17) An electrical assembly according to claim 15 or claim 16, wherein the doubled sided contact is: a) female; or b) male.
18. 18) A removable flameproof flange for an electrical connector, including: a) a substantially annular body having a first surface spaced apart from a second surface; b) a plurality of radially spaced apart through holes that extend between the first and second surfaces; and c) a plurality of radially spaced apart blind holes that extend from the second surface towards the first surface, the blind holes radially offset from the through holes, wherein, in use, the blind holes receive fasteners used to secure the removable flange to a fixed flange extending radially outward from a body of the connector proximate a first end thereof and the through holes receive fasteners used to couple the connector to a mating connector such that the first surface of the annular body forms part of at least one flameproof path.