492 results about "Explosion protection" patented technology

The invention relates to wind pressure air drilling equipment in a downhole soft outbursting coal bed and a process matched therewith. At present, as the consequent layer drilling characterized by high construction speed, low cost and high gas extraction efficiency becomes the primary option for coal control and gas control in coal mines, for soft outbursting coal beds, the gas extraction efficiency is directly dependant upon the pore-forming rate of the consequent layer drilling. The equipment comprises a boring machine, an air compressor, an orifice dust collection and dust removal device, a high-strength large through-hole drill rod, a drill bit with an inner core which can automatically fall off, and an antistatic explosion-protection PVC sieve tube; the boring machine which has large power and large torque supplies power to drilling construction; the orifice dust collection and dust removal device collects and eliminates slack carried out by wind from the orifice during drilling; and the antistatic explosion-protection PVC sieve tube is transferred from the interior of the high-strength large through-hole drill rod to the bottom of the orifice without lifting a drill on the completion of drilling, and at last remains in the orifice, thereby ensuring the completeness of drilling. The equipment and the process matched therewith provided by the invention has the advantages of increasing the pore-forming rate of the consequent layer drilling in soft outbursting coal beds, improving the effect of gas extraction, improving the working atmosphere of downhole air drilling, and protecting the production safety of outbursting coal mines.

The invention discloses a preparation process for methanol synthetic gasoline which is mixed by the following raw materials, in weight percentage: 40 percent to 95 percent of industrial methanol; national standard gasoline or basic gasoline or a mixture thereof in random proportion, or 0 percent to 70 percent of mixture of two or more basic gasoline in random proportion; 2 percent to 5 percent of fluxing denaturant; and 0.1 percent to 0.5 percent of composite functional agent. The preparation process adopts the steps: firstly the fluxing denaturant is added into the industrial methanol for stirring for 5 minutes to 10 minutes under the conditions of normal temperature, atmospheric pressure, no spark, fire prevention and explosion protection, the composite functional agent is then added thereto for the agitation for 5 minutes to 10 minutes, then the national standard gasoline or the basic gasoline or the mixture thereof in random proportion is added thereto for being continuously stirred for 5 minutes, finally completing the preparation. The methanol synthetic gasoline prepared by the process is to add inexpensive combustible liquid methanol and other liquid combustible substances with relatively large reserves in great proportions into the traditional gasoline, the substitution rate of the petroleum composition is extremely high, the energy can be saved, the national petroleum import pressure can be reduced, massive foreign exchange disbursement can be saved, and the socioeconomic performance is good, meanwhile, the process has technical advantages of environmental protection, good power performance, corrosion resistance, extensive use scope, stable quality and simple and convenient production, and being worth wide promotion.

In a circuit for safe forwarding of a physical or technical variable between at least two systems in communication with one another, which variable is represented by the value of a loop current (Is), which is adjusted by a control unit (11) by means of a current output circuit (13) in a current loop (20, 60), the current output circuit (13) has at least two parallel-connected final control elements (131, 132), controllable by the control circuit (11), as current sources for mutually independent adjustment of a value of the loop current (Is). The final control elements (131, 132) are in series with at least two likewise series-connected measurement resistors (133a, 133b). The voltage, proportional to the loop current (Is), dropping via at least one but not all of the at least two measurement resistors is fed back to the control unit (11), which compares the value of this voltage with the corresponding value of the loop current, which value is specified to at least one of the final control elements, and in the event of deviations, via a predeterminable threshold, allocates an fault value corresponding to the NAMUR recommendation NE043 to the loop current via the first final control element (131), and in the case of failure of the first final control element (131) via the second final control element (132). A monitoring circuit (17) is provided, which in the event of failure of the control unit (11) allocates an fault value that likewise corresponds to the NAMUR recommendation NE043 to the loop current via the second final control element (132). The invention, compared to embodiments based on the principle of redundance, thus makes it possible to disclose a more-favorable embodiment for monitoring and signalling faults, which makes do with only one current path. The circuit may be designed in that way. By additional wiring, the demands in terms of explosion protection by intrinsic safety, functional safety (up to at least SIL 2), HART communication, and a standardized interface in accordance with NAMUR recommendation NE43 with an upper fault current (greater than 21 mA) and a lower fault current (less than 3.6 mA) and an active mode (current source) and passive mode (current sink) can be met at the same time.

The invention discloses a hydrogen container hydrogen environment fatigue test system. One end of a high pressure hydrogen container is respectively communicated with a test container and a low pressure hydrogen container through an explosion protection pressure reducing valve, a flow regulating control valve, a first normal open stop valve and a test container depressurizing valve; the low pressure hydrogen container is communicated with the other end of the high pressure hydrogen container through a booster pump; a pressure sensor and a cycle recording device are arranged between the first normal open stop valve and an atmospheric valve; the normal open stop valve, a pressure display and a standard pressure gauge are arranged between the test container and the normal open stop valve; one path of an automatic control system operation console is respectively electrically connected with the booster pump and the pressure gauge through an excessive pressure controller; the other path of the automatic control system operation console is electrically connected with the atmospheric valve and the test container depressurizing valve. The high pressure hydrogen in the high pressure container is charged into the test container through the explosion protection pressure reducing valve and the flow regulating control valve, the explosion protection pressure reducing valve is closed when a set pressure is reached, the test container depressurizing valve is opened after maintaining the pressure for a while, and the hydrogen is depressurized into the low pressure container to complete a fatigue test cycle.

The invention discloses a measuring apparatus for capability of explosive explosion in driving of metal. The measuring apparatus is mainly composed of an explosion chamber, a metal flyer plate, velocity measurement targets, velocity measurement target supports, etc. The measuring apparatus is designed on the basis of velocity measuring principles; the explosion chamber composed of a charging sleeve and an explosion protection body is filled with a to-be-measured explosive column, the metal flyer plate is adhered on the end surface of the explosive column aligned with the charging sleeve and the explosion protection body, the explosive is fired from the other end surface of the explosive column so as to accelerate motion of the metal flyer plate, a time interval recorder is employed to acquire time when the metal flyer plate generates pulse current when passing through the velocity measurement targets at different distances, the relation curve of the distance and time of motion of the metal flyer plate is acquired through data processing, and first derivation is carried out on the curve so as to obtain the speed of the metal flyer plate at different times or distances so as to measure capacity of explosive explosion in accelerating metal.

The invention relates to a control system and a control method for a three-phase four-bridge-arm permanent magnet synchronous motor. When a conventional three-phase three-bridge-arm main circuit topological structure is short of phase or has a single-phase broken fault, the safe and reliable running of a system is difficult to maintain, and the occasions with strict requirements on redundancy and reliability of a control system in aviation, navigation, explosion protection and the like are limited. The control system structurally comprises a main circuit, wherein the 220V single-phase alternating-current input (1) of the main circuit is connected with a single-phase rectification circuit (2); the single-phase rectification circuit is connected with a four-bridge-arm inverter (3); the four-bridge-arm inverter is connected with the permanent magnet synchronous motor (8) through a bridge arm A (4), a bridge arm B (5), a bridge arm C (6) and a bridge arm D (7); the bridge arm A, the bridge arm B and the bridge arm C are connected with a current sampling circuit (10); and the permanent magnet synchronous motor is connected with a photoelectric coded disc (11). The control system and the control method are used for controlling the three-phase four-bridge-arm permanent magnet synchronous motor.

The exhaust system of an internal combustion engine includes a duct having an input end coupled to the engine for passing and processing the exhaust gases and fumes emitted by the engine such that the duct functions as an anti-explosion and fire arrester device. The duct includes a reinforced filter structure securely and firmly mounted within and across the duct opening. The filter structure is coated with a noble metal to enhance oxidation of the gases and fumes passing through the duct. An insulator layer is attached about and along the outer surface of the duct and a jacket for carrying a coolant is mounted above and about the insulator layer. The insulator layer isolates the coolant from the duct to ensure that the temperature on the external side of the jacket is less than a predetermined value. Simultaneously, the insulator layer isolates the duct from the coolant to enable the temperature within the duct to have a sufficiently high value to sustain oxidation of the gases and fumes. The input end of the duct may be connected to the engine via a first heat exchanger and the exhaust end of the duct may be connected by additional heat exchangers to the exhaust system output.

The invention discloses a dynamic polymer elastomer with a hybrid cross-linked network. The elastomer comprises the hybrid crosslinked network, and the hybrid crosslinked network contains covalent crosslinking and supermolecular hydrogen bond crosslinking, wherein the covalent crosslinking achieves a percolation threshold or more of a covalent cross-linked gel, and the hydrogen bond crosslinking is realized through hydrogen bond groups brought by polymer chain side groups and / or side chains. According to the invention, hydrogen bonds are dynamically reversible, thus the dynamic polymer elastomer has good performance such as toughness, energy dissipation performance, and self repairability. The dynamic polymer elastomer with the hybrid cross-linked network is widely applied to aspects suchas body protection in sports and daily life and work, military police body protection, explosion protection, airborne and air-drop protection, automotive collision avoidance, and electronic material impact resistant protection.

The invention provides a method for preparing a particle-filled conductive thermoplastic polymer, which belongs to the field of electromagnetic shielding material preparation. The method comprises the following steps of: firstly, preparing primary master batch of a carbon nanotube filled conductive thermoplastic polymer; secondly, preparing secondary master batch of a stainless steel fiber filled polymer; and finally, mixing the primary master batch, the secondary master batch and pure polymer master batch and performing co-injection molding on the mixture to obtain the conductive thermoplastic polymer material. The method has the characteristics of simple technical condition, easily controlled process, no residual impurities or reactant, low cost, high yield and convenient batch production. No agglomeration phenomenon occurs in the mixing process of the carbon nanotube primary master batch and the stainless steel fiber secondary master batch, so the composite material has uniformly distributed conductive filler, and the performance of the composite material is greatly improved. The method can be widely applied in the fields of civil and electric consumer products, such as consumer electronics, electrical appliance, communication devices, explosion protection safety products, information transfer and security, anti-static electricity, petrochemical industry and the like.

The invention discloses a subway shield gas tunnel construction method, which comprises the following steps: 1, dividing a gas tunnel to be constructed into one or more harmful gas pressure sections from end to end; 2, respectively constructing the harmful gas pressure sections in turn according to the construction work stages of the gas tunnel to be constructed, wherein construction processes of one harmful gas pressure section are as follows: calculating limit gas emission and correspondingly judging the level of the gas tunnel, and modifying the explosion protection performance of a shield machine, the ventilation quantity of a ventilation system and a gas monitoring control system; setting the driving speed of the shield machine; performing shield driving construction; and performing duct piece assembly and lining construction; and 3, completing constructing all the harmful gas pressure sections of the gas tunnel to be constructed until realizing the run-through of the gas tunnel to be constructed. The method has the advantages of skillful and reasonable design, convenient implementation, small construction difficulty and good construction effect, and can effectively solve the problem of safe construction for running through a shield tunnel of a gas reservoir, namely a subway shield gas tunnel.

The invention discloses a dynamic polymer with a hybrid cross-linking network. The polymer comprises at least one network structure, which contains covalent cross-linking and supermolecule hydrogen bond cross-linking; at least one network comprises covalent cross-linking; and the covalently cross-linking is above the gel point of covalently cross-linked in at least one network. Due to the reversibility of dynamic hydrogen bonds, the dynamic polymers have properties of good toughness, energy dissipation, self-healing property and the like. The dynamic polymer with a hybrid cross-linking networkprovided by the invention is widely applied to the aspects of physical protection in sports and daily life and work, physical protection of military police, explosion protection, protection of airborne troops and air drops, Impact protection of automobiles, impact protection of electronic materials, and the like.

The invention relates to a metal-based hollow-ball composite foam material and a preparation method thereof. The composite foam material comprises a metal matrix and ceramic hollow balls, wherein theceramic hollow balls are uniformly distributed in the metal matrix. The preparation method has the advantages of simple operation and low cost. In the prepared aluminum-based / aluminum oxide hollow-ball composite foam material, the interface bonding of an aluminum matrix and the hollow balls is good, the grain size of the hollow balls is larger, and the volume fraction of the hollow balls is larger. The plateau stress in a compressive stress-strain curve can reach 46MPa, the plateau phase is flat and long, and the prepared aluminum-based / aluminum oxide hollow-ball composite foam material is anexcellent light energy absorbing material. Under impulse load, the plateau stress of the composite foam can be increased to about 60MPa. The composite foam material has a significant advantage and a good application prospect in the field of shock resistance and explosion protection.

The invention discloses a halogen lamp and a manufacturing method thereof. During the manufacturing process of the halogen lamp, the lamp holder (5) of a halogen bulb (3) is directly connected with the connecting wire (6) of a core stem (4), and then the lamp holder (5) and the connecting wire (6) are both hermetically packaged at the upper part of the core stem (4), so that the halogen bulb (3) and the core stem (4) are hermetically connected as a whole. The halogen lamp has the characteristics of energy consumption, low power consumption, high luminous efficiency, long service life, high explosion-protection safety and the like. The power consumption is reduced by 30%. The halogen lamp is an ideal substitute for the conventional incandescent lamp. The manufacturing method is adaptive tothe large-batch production in the automatic production line, and can greatly reduce the productive time and the production cost, thereby greatly reducing the sale price of the halogen lamp, promotingthe generalization and the popularization of the halogen lamp, and increasing the market competitiveness of halogen lamp enterprises.

The invention discloses a vertical air shaft explosion protection door / cover capable of quickly resetting, belonging to a coal mine ventilation safety facility. The vertical air shaft explosion protection door is mainly composed of a door body 2, a heavy punch part, an inverted ventilation lock catch device and an oiling small shaft, wherein multiple groups of heavy punch assemblies of the heavy punch part are variable quality tank heavy punch assemblies 4 or variable quality tanks 19, and the variable quality tank heavy punch assemblies 4 or the variable quality tanks 19 are connected with the explosion protection door body 2 by a steel wire rope 7 and a pulley block 8; the variable quality tanks 19 are liquid storage tanks and are connected with a water supply by a water inlet and outlet pipe 13; and water reserve in the variable quality tanks is increased or reduced to replace the action of increasing or reducing the number of the weight, thus controlling the weight of the heavy punch assembly. The explosion protection door is also provided with the quick inverted ventilation lock catch device 1 and a stable synchronous elevator mechanism. The explosion protection door adopts mechanical operation to realize remote monitoring of the latch and the reset of the explosion protection door, changes outdoor operation into indoor operation, has the advantages of high resetting and latching speed, time and labour saving and safe operation, lightens physical work and improves the coal mine ventilation safety.

The invention discloses a temperature monitor for flue duct and explosion protection system, especially temperature monitor for flue duct and explosion protection system of carbon furnace. The temperature of main points in flue duct of furnace is displayed on the displayer in time and indication of trouble state and temperature setting so on are realized as equidistance multipoint measure temperature apparatus is designed in plant duct; meanwhile once overtemperature signal appears it is sent to PLC control system for gas purification out of workshop by A / D transferring and PLC controller, and it is realized by PLC control system for gas purification out of workshop that high temperature alarming, high pressure valve controlling, ventilating butterfly valve switching, temperature decreasing and fire fighting so that ultra-high temperature smoke does not appear, the possibility for firing by smoke is decreased, the safety and efficiency of equipment is improved and productive environment in workshop is improved largely.

The invention discloses an explosion protection method and a device when testing a rechargeable battery. The rechargeable battery to be tested is sealed into an explosion protection box, and a terminal point of the rechargeable battery is led to outside of the explosion protection box used for connecting a rechargeable battery testing device. A fire extinguishing apparatus and an explosion detection device are arranged inside the explosion protection box, thus when the rechargeable battery explodes, the explosion detection device triggers the fire extinguishing apparatus to put out a fire, andcuts a junction circuit of the tested battery and the rechargeable battery testing device. The invention has the advantages of simple operation, safety, low cost, capacity of guaranteeing safety of staff, protecting the rechargeable battery testing device, and preventing short circuit of the testing device caused by battery explosion.

The invention relates to a prediction method for explosion characteristics of organic mixture based on a support vector machine, comprising the following steps: for the problem that the explosion characteristics of the organic mixture under the condition of different components and different proportion is predicted and industrial process design is optimized in industrial production, taking known component content and routine property experiment data of the organic mixture as input variable, taking corresponding explosion characteristics experiment data as output variable, effectively training and predicting inner quantitative relation of nonlinearity, non-determinacy and complexity between the input variable and the output variable with the strong machine learning algorithm support vector machine method so as to establish stable, high-efficiency support vector machine prediction model. The explosion characteristics of the other unknown mixture are predicted according to the established support vector machine model so that the method has advantages of high prediction precision, speed and convenience. According to the invention, the method can predict the explosion characteristics of the organic mixture under the condition of different components and different proportion, effectively solve the problem that the actual industry production is short of the experiment data of each mixture, and has good application prospect in industrial process design, fire protection and explosion protection.

The invention relates to inorganic fireproof sheets and a production method therefor. The inorganic fireproof sheets are prepared from the ingredients in percentage by mass: 50% to 94% of inorganic mineral powder, 4% to 10% of fibers, 5% to 45% of filler and 0.5% to 6% of binding agent. The production method for the inorganic fireproof sheets comprises the steps of uniformly mixing the inorganic mineral powder, the fibers, an excitant, the filler and water so as to prepare slurry with the mass concentration of 5% to 40%, preparing sheet blanks by a copying, slurry flowing or die pressing method, carrying out curing at the temperature of 20 DEG C to 90 DEG C, and carrying out drying, sanding and cutting, thereby preparing the inorganic fireproof sheets. The sheets prepared by the method have the characteristics of environment-friendliness, low production cost, high production efficiency, light weight, high strength, fire prevention and heat insulation, thereby being capable of being extensively applied to the fire-resistive partition and explosion protection of fire doors, hung ceilings and partition walls and the fireproof coating of air pipes, steelwork beam-columns, wire cables and the like.

The invention provides a downhole monitoring system which comprises a ground control center, a plurality of lightningproof bars, a plurality of base stations, a plurality of power boxes with explosion-protection and intrinsic safety, a plurality of sensors, communication cables and a plurality of transceivers. The plurality of base stations are arranged in each important detecting point of an downhole; a ground center control system is connected with the base stations through the communication cables; a LonWorks field bus mode is adopted for transmission, wherein, each base station comprises a wireless communication module, a singlechip and a nerve cell chip. The wireless communication module is used for radio-frequency wireless bidirectional communication with the transceivers and receiving the position and state information of a mobile target of the downhole. The singlechip is used for processing various monitored environmental parameters. The nerve cell chip is used for data transmission with the ground control center through the LonWorks field bus. The plurality of transceivers are arranged on the mobile target of the downhole and has wireless bidirectional communication with the base stations. The invention can make downhole operation safer and more reliable.

The invention discloses a transmission-type optical fiber liquid level sensor with an irregular core structure. The transmission-type optical fiber liquid level sensor comprises a wideband light source, a sensing head and an optical fiber spectrum analyzer, wherein the sensing head is formed by welding a section thin core single mode fiber onto the middle of common single mode fiber, during measurement, one part of the thin core single mode fiber is positioned on a liquid level, and the other part of the thin core single mode fiber is positioned below liquid level. The common single mode fiber receives light coming from a wideband light source and is coupled to the thin core single mode fiber, so that the light is transmitted inside the thin core single mode fiber in a form of a mandrel and a cladding mode so a to form an interferometer similar to Mach-Zehnder interferometer. Light of the two parts interferes mutually and then is coupled into the common single mode fiber again and finally led into an optical fiber spectrum analyzer. By measuring drift amount of wave length of the characteristic peak in transmitted spectrum, the liquid-level variation can be calculated. The transmission-type optical fiber liquid level sensor has a compact structure, has the benefits of simplicity in preparation, high measuring accuracy, wide measuring range, safety, explosion protection and the like, and is particularly suitable for precision measurement to liquid level of inflammable liquid.

In an explosion protection for gas a turbine which includes a turbine wheel and a turbine housing surrounding the turbine wheel, wherein the explosion protection comprises a multi-layer structure of material of a high rupture strength, the explosion protection is in the form of an essentially closed pot including a bottom section and a sash extending fully around the bottom section for accommodating the turbine housing.

The invention discloses a non-contact type flexible explosion-proof method and a non-contact type flexible explosion-proof device design method, and relates to the field of social public security andexplosive disposal. The structure destroying explosion-proof theory is adopted, and in the explosion-proof process, an explosion-proof device is broken up, crushed and flied apart to absorb explodingenergy; multiple nonmetal flexible materials are composited, during explosion-proof operation, an impact wave protection layer is placed on the side close to the explosive, impact wave strength generated by exploding is weakened, and exploding heat is absorbed; a fragment protection layer is placed on the periphery of the impact wave protection layer, impact wave strength is further weakened, andthe fragment speed generated by explosion is weakened; during structural design, on the basis of the design principle of temporal and spatial variation of explosive main loads and non-contact type treatment needs and on the basis of main load decomposing protection size design and the material positioning connection principle of non-secondary-additional-damage needs, the explosion-proof structureis high in explosion protection capacity, small in self weight, flexible in treatment manner, high in safety and free of secondary additional damage.

An obstruct explosion protection skid-mounted car air filling device integrates an obstruct explosion protection air receiver, an air filling machine and auxiliary apparatus, which can be movable on the ground and is a fuel device for filling the liquefied petroleum gas (LPG) for the LPGV cars. The air receiver of the device is filled with an obstruct explosion protection material unit, a shaft and a decontamination tunnel. A pile casing filled with the obstruct explosion protection materials is arranged in the shaft, wherein the materials can be suspended outside the receiver with the pile casing 26, which is convenient for the maintenance and the clean. A liquid inlet pipe and a liquid outlet pipe are arranged in the obstruct explosion protection, a shielding case is arranged on the nozzle end, which greatly reduces the impact of the LPG liquid materials. A spray heat sink is arranged in the sun-screening heat insulation hood, and the cooling water sprayed from the atomizer can make the air receiver cool down. Due to the air receiver filled with the obstruct explosion protection materials, the accident 'boiling liquid expansion steam explosion' of the LPG can be effectively avoided to ensure the safety of the storage reservoir. The device is an integral structure, which is convenient to suspend and move.

A pressure-adjustable safety valve of a lithium ion battery consists of an end cover and a valve body, a valve cavity is formed in the valve body, the valve cavity is formed by a screw hole, a through hole and an exhaust channel with the same central shaft, a conical surface is formed between the through hole and the exhaust channel, a sealing ring is fixedly arranged on the conical surface, a steel ball is fixed on the conical surface with the sealing ring, a screw is fixedly arranged in the screw hole, a spring is fixed between the screw and the steel ball to form an exhaust hole in the valve body which forms the through hole, the exhaust hole penetrates through the valve body and connects the through hole to the outside of the valve body; a positioning screw hole is further formed in the valve body which forms the screw hole, the positioning screw hole penetrates through the valve body, and a positioning screw for fixing the screw is arranged in the positioning screw hole. The critical pressure of the exhaust of the battery is fixed, thereby better playing the roles of safety and explosion protection; furthermore, the arc-shaped exhaust mode can not cause the damage to the human body, thereby being applicable to high-power dynamical type lithium-ion batteries.

The invention discloses a mine dust grading combined dust fall device. A primary dust fall system is formed by an inner spraying device and an outer spraying device which are arranged in a coal cutter or a heading machine. The mine dust grading combined dust fall device comprises a secondary haze transform system formed by an ultrasonic wave dry haze generator and a tertiary drizzle wall haze fall system formed by a drizzle generating device. By means of the mine dust grading combined dust fall method and device, conventional instantaneous point dust fall is changed into segmental process dust fall, mine dust different size fraction can be inhibited and reduced by forming water mist particles or gas water mist particles different in particle diameter, and particle diameter grading, segmental inhibition and reduction and process transformation of mine dust in wind current of mining ports are achieved. The mine dust grading combined dust fall device can move along with pushing of the mining points and has functions of automatic control and rain stopping when people go out, dust fall efficiency is high, and dust inhibition, dust fall, explosion protection, fire protection, temperature reduction and drag reduction of return current are achieved by humidifying dirty wind. Compared with the conventional dust fall method, dust fall effect is obvious.

The invention relates to an explosion protection device of a smelting furnace. The explosion protection device comprises a pipeline with a corner, wherein one end of the pipeline is communicated with a furnace chamber passage, and the other end of the pipeline is communicated with a smoke exhaust passage; the pipeline is provided with an explosion protection opening; the upper end of the explosion protection opening is provided with an explosion protection cover; elastic devices are arranged on the two sides of the explosion protection opening; the lower ends of the two elastic devices are fixedly connected with the pipeline, and the upper ends of the elastic devices are fixedly connected with the explosion protection cover; the edge of the upper end of the explosion protection opening is provided with a circle of seal ring; a first magnetic ring is arranged on the circle on the outer side of the seal ring; the explosion protection cover is provided with a second magnetic ring; the second magnetic ring is positioned in the corresponding upper space of the first magnetic ring. Compared with the prior art, the explosion protection device has the advantages of simple structure, stable operation, capability of automatically closing the smelting furnace and good sealing property.

The invention refers to an explosion protection system for electrical apparatuses and machineries, such as manipulators or industrial robots, located in hazardous environments, i.e. environments containing explosive concentrations of inflammable gases, dusts or vapours, comprising an air supply that applies internal pressurized air into an explosion proof enclosure. The invention is achieved by a flow- and pressure sensor arranged as an integrated unit and designed to stand high dynamic forces by having low inertia, balanced arrangement of moving parts and a movement guide, e.g. an axle with a support guide, with low friction.

The invention discloses a control system for a coal mine underground water-jet cutting machine. An oil tank (1) is communicated with a hydraulic pump (4); the hydraulic pump (4) is communicated with a second pilot operated directional control valve (9); the second pilot operated directional control valve (9) is communicated with the left oil cavity and the right oil cavity of a dual-purpose boosting cylinder (26) respectively; a first mandrel plunger valve (14) and a second mandrel plunger valve (15) are arranged in the left oil cavity and the right oil cavity respectively; the second mandrel plunger valve (15) is communicated with a first pilot operated directional control valve (8); the first mandrel plunger valve (14) is communicated with the first pilot operated directional control valve (8); the first pilot operated directional control valve (8) is communicated with the hydraulic pump (4); and the left water cavity and the right water cavity of the dual-purpose boosting cylinder (26) are communicated with an energy accumulator (23) and a water pump (22) respectively, so that a control system is formed as a whole. The entire system can be operated without generating electric sparks or other sparks, can be applied to occasions such as mining, fire control, rescue, explosion protection and the like, and is particular suitable for performing coal mine underground cutting operation.