Explosion-proof connector device

Abstract

FIELD: mining industry.SUBSTANCE: invention relates to an explosion-proof connector device intended for use in coal mines, for quickly connecting electrical circuits with a voltage of up to 1140 VAC and a frequency of 50 and 60 Hz when connecting flexible cables to electric motors and electrical equipment of coal combines and other face machines, as well as for connecting two sections of flexible cables laid along mine workings of coal mines and pits. The explosion-proof connector comprises a plug, a socket with contact elements, a union nut to prevent spontaneous disconnection of the plug from the socket, and additionally has control circuits and a grounding contact, wherein the plug consists of a metal housing with an insulator with built-in contact fingers made of brass, the socket consists of a metal housing with installed sockets in such a way that the grounding socket protrudes beyond the end of the housing to ensure visibility of the orientation of the connection of the plug with the socket, and the power, control and grounding sockets have different lengths to ensure electrical interlocking, wherein when disconnecting the connector, the control circuit contacts are opened first, then the power circuit contacts, and the grounding contact is the last.EFFECT: providing an explosion-proof connector device, having a design solution characterized by reduced overall dimensions, consisting of two parts – a plug and a socket, in which the sockets and contacts are compactly located, eliminating the spontaneous connection or disconnection of the plug from the socket.1 cl, 4 dwg

Description

[0001] The invention relates to the field of the mining industry, namely to an explosion-proof connector designed for work in coal mines, in explosive mixtures of methane or coal dust with air, can be subjected to the mechanical impact of falling rock, as well as aggressive alkaline and acidic mine waters, is intended for the rapid connection of electrical circuits with a voltage of up to 1140 V at a frequency of 50 and 60 Hz alternating current when connecting flexible cables to electric motors and electrical equipment of coal combines and other face machines, as well as for connecting two sections of flexible cables laid along the mine workings of coal mines and pits.

[0002] Technology Level

[0003] An electrical connector for transmitting energy and data is known, comprising a plug part, inside which an insulator with pins for an electrical contact and a tip for a data bus contact is installed, and a socket part, inside which an insulator with sockets for an electrical contact and a tip for a data bus contact is installed, as well as a device for fixing the tips in a closed state, characterized in that the mating end of the plug part, provided with a sealing ring, has the ability to tightly enter the internal cavity of the socket part to perform switching of their contacts (see patent RU on PM No. 122804, IPC H 01 R 24 / 00, H 01 R 13 / 66, published 12 / 10 / 2012, bulletin No. 34).

[0004] The disadvantage of this utility model is that it only provides moisture-proofing properties. The closest in technical essence and achieved positive effect, and adopted by the authors as a prototype, is:

[0005] 1. An explosion-proof hybrid connector comprising a plug and socket portion with contact elements of a power circuit and a data line, wherein the plug portion has the ability to be tightly coaxially inserted into the socket portion for switching the corresponding contact elements, wherein a control circuit is introduced with contact elements in the plug and socket portions, wherein the contact elements of the power and control circuits are installed with the ability to close the corresponding contact elements first of the power circuit, and then of the control circuit, which, in turn, is connected to an introduced starter having the ability to close the power circuit.

[0006] 2. An explosion-proof hybrid connector according to claim 1, wherein a union nut is introduced that can be screwed onto the socket part to ensure smooth joining of the plug and socket parts and fixing them in the closed position (see patent RU on PM No. 127258, IPC H 01 R 24 / 00, published on 20.04.2013, bulletin No. 11).

[0007] The disadvantage of this utility model is that it cannot be used for switching spark-hazardous circuits, since the closing and opening of the contact elements of the power circuit under voltage leads to sparking, which is unacceptable in an explosive atmosphere.

[0008] Disclosure of invention

[0009] The objective of the proposed invention is to develop an explosion-proof connector with reduced overall dimensions, a compact arrangement of sockets and contacts, the elimination of spontaneous connection and disconnection of the plug from the socket, the possibility of operation in AC networks with a voltage of up to 1140 V and a frequency of 50-60 Hz.

[0010] The technical result that can be achieved with the help of the proposed invention is reduced to the creation of an explosion-proof connector, having such a design solution of the connector, which has reduced overall dimensions of the connectors, consisting of two parts of the plug and socket, compactness of the arrangement of the sockets and contacts, the elimination of spontaneous connection-disconnection of the plug with the socket, the possibility of operation in AC networks with a voltage of up to 1140 V and a frequency of 50-60 Hz.

[0011] The technical result is achieved using an explosion-proof connector containing a plug, a socket with contact elements, a union nut to prevent spontaneous disconnection of the plug from the socket, a main circuit, wherein the explosion-proof connector additionally has control circuits, a grounding contact, and the connector is made in the form of a connected plug of a certain design and a socket of a certain design, wherein the plug consists of a metal housing with an insulator with built-in contacts made of brass, with contact fingers of a cable entry and a cover with a chain, wherein the housing of the linear plug is similar in design to the housing of a cable socket, and on its front part a thread is made for screwing on the socket nut when connecting (pulling together) the plug with the socket, and three power, three control and one grounding contact fingers are installed in the insulator,wherein the grounding pin performs the function of a guide pin for orienting the plug when connected to the socket, and the socket consists of the following assembly units: a housing, an insulator with contact sockets, a cable entry and a cover with a chain, wherein three power, three control and one grounding contact sockets are installed in the insulator, and the grounding socket, in addition to its direct purpose, performs the function of a guide socket when mating the socket with the plug, the socket protrudes beyond the end of the housing, thereby providing visibility when orienting the mating of the plug with the socket, wherein the design of the insulator ensures the separation of the main spark-hazardous and control spark-safe electrical circuits in accordance with GOST 31610.11, and in the explosion-proof connector, the power, control and grounding sockets have different lengths to meet the following condition: when disconnecting the explosion-proof connector, the control circuit contacts must open first,then the contacts of the main circuit, and lastly the grounding contact, thus ensuring the interlock of the explosion-proof connector, in which the power contacts are disconnected after remote disconnection of the voltage from these contacts.

[0012] Brief description of drawings and other materials

[0013] Fig. 1 shows a general sectional view of an explosion-proof connector.

[0014] Fig. 2 shows the same, explosion protection means of the explosion-proof connector device, general sectional view.

[0015] Fig. 3 shows the same, the plug and socket are linear, general view in section.

[0016] Fig. 4 shows the same, cable plug and socket, general view in section.

[0017] Implementation of the invention

[0018] The explosion-proof connector is manufactured in accordance with the requirements of TU 3424-003-00213569-2007. The connector is manufactured in climatic versions U and T, placement category 5 according to GOST 15150. The design of the explosion-proof connector is possible as follows, classified by purpose: linear plug - linear socket, fixed plug - fixed socket, cable plug - cable socket, built-in plug - built-in socket. The climatic performance is carried out according to GOST 15150. Nominal values ​​of climatic factors - according to GOST 151Ь0 and GOST 15543.1, while: - the lower and upper value of the ambient air temperature is from minus 60 to plus 50 °C, - the upper value of the relative humidity of the ambient air is up to (98+2) and at a temperature of (35+2) °C; - the environment is explosive gas, for example, methane, and coal dust, while the dust content is no more than 1200 mg / m3 3; - nominal values ​​of mechanical external influencing factors - according to GOST 17516.1. Control circuits of the explosion-proof connector are made intrinsically safe. Any working position in space is possible. The explosion-proof connector has seven contacts: three contacts of the main circuit, three - of the control circuits and one - grounding. The device of the explosion-proof connector has a union nut, providing their connection and disconnection. The force of disconnecting the plug and socket using the key GOST 16934 is no more than 245 N (25 kg). Mechanical wear resistance of the explosion-proof connector device is 6300 connection-disconnection cycles. The service life of the explosion-proof connector device before write-off is 5 years, and during its service life it is not subject to major repairs.

[0019] The explosion-proof connector's protection level against external environmental influences is in accordance with GOST 14254: for linear connectors - in the connected position; for fixed connectors - in the connected position when installed in the product. The insulation resistance under normal climatic conditions is at least 10 megohms.

[0020] The explosion-proof connector has the following design. It consists of a cable socket 1 and a linear plug 2. The cable socket 1 consists of the following main assembly units: a housing 3, an insulator 4 with contact sockets, a cable entry 5, and a cover 6 with a chain. The housing is a welded metal structure, with a coupling nut 7 mounted on the front end and a cable entry socket on the opposite end.

[0021] Inside the housing, crackers 8 are welded for fastening the insulator with screws 9. Screw 10 fastens the grounding strip 11 to cracker 8. Three power 12, three control 13 and one grounding 14 contact sockets are installed in the insulator. The grounding socket, in addition to its direct purpose, serves as a guide socket when mating the socket with the plug. The socket protrudes beyond the end of the housing, which provides visibility when orienting the mating of the plug with the socket. The design of the insulator ensures separation of power spark-hazardous and control spark-safe electrical circuits in accordance with GOST 31610.11. The ends of the insulator are marked with the markings of the contacts: power (main) circuit - L1, L2, L3, control circuits - K1, K2, K3 and grounding . The power, control and grounding sockets have different lengths to meet the following condition: when disconnecting the connector, the control circuit contacts should open first, then the main circuit contacts and lastly the grounding contact. This ensures electrical interlocking of the connectors, during which the power contacts are disconnected after remote disconnection of voltage from these contacts. The contact sockets have clamps 15, 16 for connecting and securing the cable cores. The insulator is installed by a press fit in a metal sleeve 17. Cable entries are intended for entering, sealing and securing the cables supplied to the connectors. They are made with a nominal diameter of the through hole of 30 mm. The range of input cables is 18-29 mm, the diameters of the concentric slots in the sealing ring are 21, 25 and 29 mm. The cable entries consist of a rubber sealing ring 18 installed in a socket 19, a coupling 20 and a plug 21.The plugs are designed to protect the interior of the connector's input compartment from dust and moisture. Cable entries are secured against twisting and pullout with clamp 22, which relieves the cable cores from tensile stress and torsion. Cable sealing occurs through the deformation of rubber ring 18 by coupling 20. Cover 6 serves to seal the interior of the socket when the explosion-proof connector is disconnected. Cover 6 is attached to the housing by a chain. The linear plug consists of housing 23, insulator 24 with contact pins, cable entry 5, and cover 25 with a chain. The housing of linear plug 23 is similar in design to the housing of a cable socket and differs in that the front portion is threaded for screwing on the socket nut when mating (tightening) the plug to the socket. Three power 26, three control 27 and one grounding contact fingers 28 are installed in the insulator.The earthing pin serves as a guide pin to orient the plug when connected to the socket. The corresponding markings on the contact pins are L1, L2, L3, K1, K2, K3, and so on. applied to the ends of the insulator.

[0022] All other parts and assemblies are standardized with the cable socket. The plug is connected and disconnected from the socket using a union nut, which is secured to the socket body and screwed onto the plug body. Turning the nut clockwise tightens and seals the plug body to the socket body, while the plug's contact pins engage the socket's contact receptacles. The housings are sealed with a rubber O-ring. A special wrench must be used when tightening and loosening the nut. The explosion-proof fixed connector has fixed plugs and sockets, essentially the front parts of line plugs and sockets, cut to the edge of the insulators and designed for installation in the product's explosion-proof enclosure. The stationary plug consists of a housing 1, an insulator 2 with contact fingers, a cover 3 with a chain 4 and a casing 5.The housing, at the end opposite the thread, has a flange for attaching the connector to the enclosure wall. Attachment is accomplished with two strips 6 and 7 using four bolts. A key is installed on one of the strips; this key engages a groove on the housing flange, preventing the explosion-proof connector from rotating. During transportation and storage, housing 5 protects the explosion-proof connector from dust and moisture, and the explosion-proof surfaces and insulator 2 with contact pins from damage. Rubber gasket 8 is used to seal the explosion-proof connector between the housing and the enclosure wall. All other assemblies and components are standardized with the in-line plug and are described above. The fixed socket differs from the fixed plug only in the insulator with contact elements integrated into the housing.The design of the fixed socket is similar to that of the fixed plug and the insulator with contact sockets of the cable socket; the components and assemblies are standardized. Connector markings comply with the requirements of GOST 30849.1.

[0023] An explosion-proof connector that has passed quality control is stamped with a quality control stamp. Each contact terminal on the plug and socket insulators is marked by pressing. Power contacts are marked L1, L2, L3, control contacts are marked K1, K2, K3, and the grounding contact is marked with a symbol. . Packaging and preservation of the explosion-proof connector - according to GOST 23216 for storage and transportation conditions. The explosion-proof connector is manufactured with the following types of explosion protection: "flame-proof enclosure" and "intrinsically safe electric circuit i". In this case: - the fixed explosion-proof device is an Ex-component with explosion protection marking Ex db ia I Mb U / Ex db ia IIA T4 U; the cable has the explosion protection level: - "explosion-proof" - (PB) with types of explosion protection; - "flame-proof enclosure - (d) and intrinsically safe electric circuit i" with the level "ia" and has explosion protection marking PB Ex db ia I Mb / lEx db ia IIA T4 Gb. The level and type of explosion protection are achieved by the following measures and means:

[0024] - placement of non-sparking current-carrying parts of contact connections in an explosion-proof enclosure that has a high degree of protection against the risk of mechanical damage according to GOST 31610.0, which can withstand the pressure of an explosion and prevents its transmission to the environment;

[0025] - the design of electrical contact clamps that comply with GOST 31610.0 and eliminate the transmission of contact pressure through the electrical insulating material;

[0026] - an electrical interlock designed in such a way that when the plug and socket are disconnected, the control circuit contacts are opened first, then the main circuit contacts, and the ground contact is opened last;

[0027] - cable sealing with elastic rubber ring;

[0028] - the design of cable entries, which have a device to prevent cable pulling out and to eliminate the transfer of tensile and torsional forces to the contact connections; the degree of protection against external influences - IP66 according to GOST 14254, ensured by the use of sealing gaskets at the junction of the plug and socket housings and sealing rings in the cable entries; the strength of the parts of the explosion-proof enclosure according to GOST IEC 60079-1, while the strength of each enclosure is checked during manufacture with an excess pressure equal to one and a half times the explosion pressure for the time required for inspection, but not less than 10 s;explosion-proofness of connectors, which is ensured by the use of slot explosion protection, the mating parts are designated by the word "Explosion" with an indication of the permissible parameters of explosion protection according to GOST IEC 60079-1: the maximum width and minimum length of the slots, the roughness of the mating surfaces that form explosion-proof slots, other information and dimensions are also provided that ensure the explosion-proofness and explosion resistance of the enclosure, which must be observed during operation, the dimensions of cylindrical explosion-proof slots are ensured by the design; manufacturing technology and are guaranteed by the manufacturer;

[0029] - limiting the maximum temperature of contact connections under normal operating conditions, which does not exceed 35°C;

[0030] - limiting the temperature of the outer surface of the connectors, which in steady-state operating mode, taking into account the maximum ambient temperature, does not exceed 150°C, which complies with the requirements of GOST 31610.0 for electrical equipment of group I;

[0031] - protection of explosion-proof surfaces from corrosion by galvanic coating and anti-corrosion protective grease, all screws and nuts fastening parts with explosion-proof surfaces, as well as current-carrying and grounding clamps are protected from self-unscrewing with adhesive fixative or spring washers;

[0032] - grounding of connector housings by electrically connecting them to grounding contacts;

[0033] - access to the external bolts and screws of cable compression joints and clamps that protect the cable from pulling out and turning, using a special tool; the explosion protection type "intrinsically safe electrical circuit i" is ensured by meeting the requirements for creepage distances and electrical clearances between spark-hazardous and spark-safe circuits in accordance with the requirements of GOST 31610.11;

[0034] - the presence of warning signs: - “Open after disconnecting from the network” and “Disconnect after disconnecting from the network”.

[0035] Example of installation of plugs and sockets using the example of an explosion-proof linear connector.

[0036] Using a special wrench, turn nut 7 counterclockwise to disconnect the explosion-proof linear connector. Then loosen screws 9, detach clamps 22, remove pressure couplings 20 and sealing rings 18. Loosen screws 9 and 10 and remove plug 13 and socket 11 from the housings. Inspect them. Damaged insulators with cracks or damaged ribs are not allowed for operation. During inspection, check the condition of the explosion-proof surfaces of the parts being disassembled. Scratches, cracks, dents and other defects are not allowed. In sealing ring 4 of the cable entry, make a cut on the seal corresponding to the diameter of the sealed uncut end of the cable and cut it to the end. In this case, the inner diameter of the ring must be equal to the outer diameter of the clamped part of the cable or more or less by no more than one millimeter. The rubber layer should be removed without tearing.When installing an explosion-proof connector, ensure that the maximum outer diameter of the cable is 1-2 mm smaller than the diameter of the through-hole in the cable gland. Thread the cable through cable gland 3, rubber ring 4, and insert it into the plug (socket) housing through the opening in the socket 5 of the cable entry. Dismantle the supplied cable. Remove the hose sheath at the termination point. Remove the rubber core at the cable termination root. Remove the semiconductive screen from the main cable conductors. Remove any remaining graphite from the semiconductive screen from the surface of the insulation of the main conductors with a swab soaked in white spirit (GOST 3134-78). Remove the rubber insulation from the ends of the main cable conductors over a length of (12 ± 1) mm, strip, and connect the conductors to the sockets and contact pins. The ends of the control cable cores, the grounding core and the screen are stripped and connected according to the markings to the sockets and contact fingers, respectively.The control and grounding conductors are additionally insulated with PVC insulating tubes complying with GOST 19034-82. The clamped ends of the main, control, and grounding conductors are inspected, and if any protruding wires are found extending beyond the clamps, the conductors are re-secured. When installing conductors of reduced cross-section, the diameter of the fastening end can be increased by repeatedly bending the conductor, followed by crimping and tinning. Then, screws 9 are tightened, while bar 14 is secured and pressed against the housing. Sealing rings 4 are installed in the cable entry sockets and pressed against cable joint 3 using bolts 15. Secure the cable against pulling and rotation with clamp 1. Cable sealing must be performed with particular care, as the explosion-proofness of the input device depends on it. The reliability of the seal is checked by applying axial force to the cable - there should be no visible movement of the cable.The use of sealing rings manufactured without conforming to the manufacturer's working drawings is not permitted. Upon completion of installation, measure the insulation resistance between the power terminals of opposite phases, and between the power terminals and the connector body; it must be at least 10 megohms. When installing an explosion-proof connector, the plug must be mounted on the end of the cable coming from the electric motor, protecting the explosion-proof surfaces from damage. Then connect the plug to the socket using nut 7, rotating it clockwise until it stops. After installation, all galvanic elements are coated with preservative greases, such as Litol-24, AMS-3 Grease, or GOI-54p, to reduce environmental exposure and prevent corrosion.

[0037] The proposed invention has the following advantages compared to the prototype and other known technical solutions:

[0038] - design solution of explosion-proof connector, consisting of two parts: plug and socket;

[0039] - high mechanical strength;

[0040] - enclosing normally sparking parts in an explosion-proof shell, which ensures high explosion safety of the explosion-proof connector device;

[0041] - the earthing socket of the socket is designed to protrude beyond the end of the housing, which ensures the orientation of the connection between the plug and the socket is visible;

[0042] - implementation of power, control and grounding sockets of different lengths, which ensures electrical interlocking;

[0043] - reducing the overall dimensions of the device;

[0044] the ability to operate the device in AC networks with voltage up to 1140 V and frequency of 50-60 Hz.

Claims

An explosion-proof connector comprising a plug, a socket with contact elements, a union nut to prevent spontaneous disconnection of the plug from the socket, a main circuit, characterized in that the explosion-proof connector additionally has control circuits, a grounding contact, and the connector is made in the form of a connectable plug of a certain design and a socket of a certain design, in which the plug consists of a metal housing with an insulator with built-in contacts made of brass, with contact fingers, a cable entry and a cover with a chain, wherein the housing of the linear plug is similar in design to the housing of the cable socket, and on its front part a thread is made for screwing on the socket nut when connecting (pulling together) the plug with the socket, and in the insulator three power, three control and one grounding contact fingers are installed, wherein the grounding finger performs the function of a guide finger for orienting the plug when connecting to the socket,and the socket consists of the following assembly units: a housing, an insulator with contact sockets, a cable entry and a cover with a chain, while three power, three control and one grounding contact sockets are installed in the insulator, and the grounding socket, in addition to its direct purpose, performs the function of a guide socket when mating the socket with a plug, the socket protrudes beyond the end of the housing, thereby providing visibility when orienting the mating of the plug with the socket, while the design of the insulator ensures the separation of the main spark-hazardous and control spark-safe electrical circuits in accordance with GOST 31610.11, and the power, control and grounding sockets have different lengths to meet the following condition: when disconnecting the explosion-proof connector, the control circuit contacts must open first, then the main circuit contacts, and the grounding contact last, thereby ensuring the locking of the explosion-proof connector,in which the power contacts are disconnected after remote disconnection of voltage from these contacts,

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