44results about How to "Avoid equipment accidents" patented technology

The invention provides an automatic detection and regulation method and an automatic detection and regulation circuit for an air conditioner. The circuit comprises a singlechip control circuit, a phase-sequence detection circuit, a relay driving circuit, a display circuit, a power supply circuit, a compressor overcurrent protection circuit, a relay contact adhesion detection circuit and a startup detection circuit. When the technical scheme is adopted, the power supply circuit provides a working voltage for the phase-sequence detection circuit, the display circuit, the singlechip control circuit and the relay contact adhesion detection circuit; the signals of the phase-sequence detection circuit, the relay driving circuit, the compressor overcurrent protection circuit, the relay contact adhesion detection circuit and the startup detection circuit are sampled and input into the singlechip control circuit; after the signals are processed by the singlechip control circuit, control instructions are output to a corresponding circuit to be executed; and the display circuit displays a phase-sequence output state and codes of various faults such as open phase, relay contact adhesion, relay operation failure, overcurrent and the like and gives a buzzing alarm, so that equipment faults caused by reversed phase, open phase or voltage unbalance are avoided.

The invention relates to a dendrite corrosion low-power checkout integration method. The method comprises the following steps of: firstly, milling, grinding, polishing a sample so that the checkout surface reaches the mirror smoothness; then, corroding the sample and eroding a corrosion reagent on the checkout surface for 1-2 min; washing, wiping and drying; and scanning and shooting by adopting a low-power detection suspension scanner camera device after the checkout surface is corroded, and then, processing and printing the image. The method provided by the invention can realize dressing detection and solve the defect existing in the suspension sample by adopting the low-power detection suspension scanner camera device. The invention can detect the cast-state structure of low-carbon steel, medium-carbon steel, high-carbon steel, low-alloy steel or alloy steel, steel blanks and large-size steel samples, observe the solidification structure and the defects thereof as well as the evolution conditions of the solidification structure and the defects of a thermally processed sheet and also check the relation between the solidification structure and the defects and has the advantages of accuracy, easy operability, environmental protection, and the like.

The invention relates to voltage transformer protection technology, specifically to a device for preventing reverse charging of a secondary side of a voltage transformer, and solves the problem that existing voltage transformer protection technology cannot completely prevent a reverse charging phenomenon from occurring in a voltage transformer. The device for preventing reverse charging of the secondary side of the voltage transformer includes a three-phase air switch, a first spring, a lock rod, a support, a lever, a top rod, a bimetallic strip, an electric heating element, a reverse charging release, an overcurrent release, an undervoltage release, and a second spring; a right end of the first spring is fixed to a first phase moving contact of the three-phase air switch; a left part side face of the lock rod is fixed to the first phase moving contact, a second phase moving contact and a third phase moving contact of the three-phase air switch; a right end of the lock rod is provided with a first hook-shaped part; a left end of the lever is provided with a second hook-shaped part which are in a clasp joint with the first hook-shaped part; and a right end of the lever is hinged to the support. The device for preventing reverse charging of the secondary side of the voltage transformer in the invention is suitable for a power grid.

Provided are an inter-rack technical roller replacement device and method. The inter-rack technical roller replacement device is composed of pulling boards, a mobile trolley, jacks, hanger arms, hooks, sliding blocks, a cross beam and hinge pins. The pulling boards are arranged on the two sides of the mobile trolley. The hanger arms are hinged to the pulling boards, and a sliding slot is formed in the other side of each hanger arm. The sliding blocks with the hooks are connected to the interiors of the sliding slots in a sliding mode. Each jack is arranged under the corresponding hanger arm. A roller replacement trolley track and an inner track of a machine frame are connected. A crane is used for placing the mobile trolley on the roller replacement trolley track to be fed into a leveling machine frame; the jacks are utilized for jacking up the hanger arms after the hanger arms, the cross beam and the jacks are installed in positions; a technical roller slips to the roots of the sliding slots; the jacks are descended so that the technical roller can be placed on the mobile trolley; and then the technical roller is conveyed to a roller replacement trolley outside the leveling machine frame by the mobile trolley. Installation of a new technical roller can be completed by carrying out contrary operations. By means of the inter-rack technical roller replacement device and method, personal accidents and equipment accidents can be avoided, the roller replacement time can be shortened, the labor intensity is relieved, the shutdown loss is reduced, the unit operation rate is increased, and the roller surfaces are effectively prevented from being damaged.

The invention discloses a full-automatic unmanned operation management system for a crown block. The full-automatic unmanned operation management system comprises a Level 3 system, a Level 2 system, avehicle image recognition system, an entrance guard management system, a crown block control system, a ground safety system, an operation room and a step beam control system. According to the full-automatic unmanned operation management system, the three-dimensional image imaging technology, the anti-shake control technology, the safety protection and other hardware equipment are added on the basis of the crown block automation system, and the full-automatic unmanned operation and management of the storage area set crown block are realized by combining an automatic control model of the crownblock and the control function of a storage area. The invention aims as achieving efficient management of projects such as inventory management and material warehousing on the basis of logistics informatization, so that the structure of the personnel is optimized, and the personnel are reasonably equipped; and the operation efficiency of the crown block is improved through the operation standardization of the crown block, and product damage and equipment accidents caused by manual crown block operating errors are prevented.

The invention discloses a detection method and a detection device for traction of a point switch between a turnout point rail and a stock rail. The detection device comprises a detector consisting of a shell, a liquid crystal display screen, number keys and a data processing board, and is characterized in that a pressure sensor circuit board is arranged in an iron plate groove at the middle portion of an iron plate handle, and two ends of a data signal line are respectively connected between a data processing lead interface and an iron plate lead interface; an emergency dismounting step and a test iron plate pressed between the turnout point rail and the stock rail are sequentially fixed at the bottom end of the iron plate handle, a pressure sensor is fixed in a pressure sensor groove in the test surface of the test iron plate, and the pressure signal line of the pressure sensor is connected with the input end of the pressure sensor circuit board in the iron plate groove through a sensor signal line hole. According to the detection method and the detection device, the traction of the power-driven (hydraulic) point switch can be timely learned during ordinary maintenance. The detection method and the detection device have the advantages being capable of automatically detecting traction of the railway point switch between the turnout point rail and the stock rail, accurate and reliable in detection result and convenient to test.

The invention discloses an intelligent control system of a detachable container type garbage truck. The intelligent control system of the detachable container type garbage truck comprises an manual operation box, a controller, a sliding arm appropriate extension travel switch, a lifting arm appropriate fall travel switch, a sliding arm appropriate retraction proximity switch, a loading and unloading container state lifting arm appropriate extension travel switch, a locking frame appropriate extension travel switch, a loading and unloading state lifting arm appropriate extension proximity switch and a locking frame appropriate retraction travel switch. The controller controls a lifting arm oil cylinder, a sliding arm oil cylinder and a locking frame oil cylinder to complete sequential actions of the overall truck. The controller receives a detection signal of a detection switch and judges the positions of a sliding arm, a locking frame and a lifting arm, the manual operation box sends instructions to control the lifting arm oil cylinder, the sliding arm oil cylinder and the locking frame oil cylinder to sequentially act, and the intelligent control effect is achieved.

The invention relates to the technical field of power grid maintenance, and discloses a device for replacing a permanent-magnet circuit breaker controller in a charged mode. The device comprises a first plug, a second plug, a third plug, a fourth plug and a connecting guide rod, wherein the upper end of the first plug, the upper end of the second plug, the upper end of the third plug and the upper end of the fourth plug are respectively fixedly installed on the connecting guide rod and electrically connected with the connecting guide rod. The first plug, the second plug, the third plug and the fourth plug are respectively inserted into a first terminal, a second terminal, a third terminal and a fourth terminal to break the current circuit of the controller, then the controller is powered off, and the controller can be replaced, so that charged replacement of a permanent-magnet circuit breaker is realized, the phenomenon of power-off caused by damage of the permanent-magnet circuit breaker controller is prevented, the maintenance of lines is reduced, the line shutdown time is reduced, personal injury and equipment accidents caused by maintenance are avoided, and the use of insulating tension is not influenced.

The invention relates to a multifunctional combined test valve for an SF6 gas moisture and decomposer tests to equipment of a transformer substation. The test valve comprises a three-way pin valve and an angle valve which are assembled together, wherein two valve joints of the angle valve are of right angles, the valve rod of the angle valve is of a column shape, and ventilating slots corresponding to the valve joints which are vertical to the valve rod are formed on the valve rod; and valve joints vertical to the valve rod on the angle valve are connected to the valve joints which are over against the valve rod of the pin valve and arranged on the pin valve. According to the multifunctional combined test valve, the operation of a humidity and decomposer test can be completed by once assembly and disassembly in the SF6 gas moisture and decomposer test to the equipment of the transformer substation; and power grid safety is better guaranteed in a live test, the emission amount of SF6 gas is reduced, and the air quality is improved.

Disclosed are a hot rolling workshop roof heat preservation structure and method. The hot rolling workshop roof heat preservation structure comprises an expanded steel diamond mesh, a rock wool insulation board, a tire base cloth type SBS waterproof roll and a cold bonding type SBS waterproof roll, the expanded steel diamond mesh is arranged on color steel tiles, the rock wool insulation board is arranged on the expanded steel diamond mesh, the tire base cloth type SBS waterproof roll is connected with the rock wool insulation board through anchoring parts, and the tire base cloth type SBS waterproof roll is covered with the cold bonding type SBS waterproof roll. Compared with the prior art, the structure and method have the advantages that the service life of a roof heat preservation layer is prolonged, the water prevention performance of a roof is improved, equipment accidents caused by rain leakage are avoided, and safety accidents caused by strength reduction of the color steel tiles of the roof are avoided.

The invention provides a shear spring, which belongs to the field of general mechanical components and is designed for overcoming the deficiency that the prior rubber shear spring is low in strength and poor in bearing capacity. A main body of the shear spring is a cylinder which is made from nonmetal elastic materials and is provided with a hole in the middle; two metal installation claw discs are pre-embedded inside a spring body near two end faces of the spring body; the installation claw discs are provided with threaded holes for installation and use; the two installation claw discs are connected together through a safety steel wire ring; and two ends of the installation claw discs are fixed by positioning pins. The shear spring has the characteristics of convenient installation, safe reliable use and long lifespan, and can be widely applied to vibrating-screening or feeding machines or other equipment with high acting force and vibration intensity in industrial and mining enterprises.

The invention discloses an abrasion monitoring instrument of a digital displaying bearing. The instrument comprises a housing, wherein a phase sequence alarming indicator light, an abrasion state indicator light and an abrasion loss displaying area are arranged on the housing; an integrated circuit is arranged in the housing and used for directly converting G1 and G2 AC signals guided out by a motor into digital signals; the integrated circuit comprises a main control circuit, a display circuit, a phase sequence indicating circuit and a power input and current output circuit. With the adoptionof the abrasion monitoring instrument of the digital displaying bearing, the radial abrasion of a shield pump bearing can be monitored in real time; the instrument is applicable to on-site inspectionand monitoring, and the working condition of the shield pump bearing can be remotely monitored through a computer; in case of abnormality or fault in the shield pump bearing, alarming can be immediately carried out through a DCS system or a vehicle can be immediately automatically stopped, thus equipment accidents such as burnout of a shield pump can be prevented, and as a result, the working safety and the reliability of the shield pump can be improved.

The invention relates to the technical field of ferrous metallurgy, in particular to a safety interlocking device of a thin oil sealing dry gas holder. The safety interlocking device of the thin oil sealing dry gas holder comprises a counter weight pendant mound, the two sides of the counter weight pendant mound are provided with fixing devices, the fixing devices are provided with clamping grooves, and the clamping grooves are formed in a pendant mound guide rail. The upper end and the lower end of the pendant mound guide rail are respectively provided with an interlocking switch, the middles of the interlocking switches are hinged to a gasometer shell, and one end of the gasometer shell is arranged on the pendant mount guide rail. The safety interlocking device of the thin oil sealing dry gas holder has the advantages that interlocking misoperation can be avoided, and safety operation factors can be improved.

The invention provides a train pulling platform operation control system, which comprises a train pulling platform driving control module, a stopper control module, a pusher control module, an empty line backstop control module and a railway wagon recognition module, wherein the train pulling platform driving control module, the stopper control module, the pusher control module, the empty line backstop control module and the railway wagon recognition module are respectively connected in parallel, and then the front ends of the train pulling platform driving control module, the stopper control module, the pusher control module, the empty line backstop control module and the railway wagon recognition module are connected with a fire wire A through a switch SA1. The operation control system is jointly controlled by an inductance approach switch and other electronic components, the accuracy and the stability of operation are higher, the alignment accuracy is ensured, the operation logic is reliable, the occurrence of equipment accidents and train leather dropping accidents can be effectively avoided, the operation meets the requirement on technical transformation, and proved by production practice, the improved train pulling platform can be operated safely and reliably, the normal processing of production can be ensured, and better efficiency of cost reduction and efficiency increase can be obtained.

The invention provides a hot-rolling seamless pipe antioxidation disc device. The device comprises a power transmission mechanism and at least four disc transmission devices connected in series. The power transmission mechanism comprises a base, a motor, a speed reducer, a coupler and a driving wheel. Each one of the disc transmission devices comprises a stepped shaft, a chain wheel, a disc, resin tiles, tile covers, a tank and a bearing pedestal. The two resin tiles are fixed to the tank with water inlet and outlet pipes by the tile cover. The stepped shaft is inlaid in the resin tiles. The middle of the stepped shaft is provided with the disc. An extension end of the stepped shaft is provided with the chain wheel. The chain wheel is connected to the driving wheel by a chain. The shaft of the driving wheel is inlaid in the bearing pedestal with the bearing. The shaft of the driving wheel is connected to the motor by the speed reducer and the coupler. The hot-rolling seamless pipe antioxidation disc device prolongs a motor service life, prevents an equipment accident, reduces spare part consumption, reduces labor intensity, reduces an equipment cost and a production cost and improves seamless steel pipe quality and rolling yield.

The invention relates to an intelligent network monitoring method and system for a theodolite, and belongs to the technical field of Internet of Things. The method and the system have the advantages that an independent intelligent network monitoring system is established for the running states of theodolite equipment; an embedded type processing platform is used for receiving, collecting and processing the information of the theodolite equipment via rich data interfaces for collection and communication, and the human-machine interaction is performed, so as to more visually and conveniently perform real-time online monitoring and warning on the theodolite, help a user to timely find the early fault hidden hazards of the theodolite equipment, avoid the occurrence of major equipment accidents, ensure the safety running of whole theodolite, and reduce the equipment loss and maintenance cost due to nonscheduled shutdown and crashing of the theodolite equipment; the running state data, fault information and warning state information of the theodolite equipment are stored, and the long-time running data of the theodolite equipment is established, so as to provide reliable data for the subsequent accident query, optimal design and the like.

The invention discloses a method for monitoring the aging degree of transformer insulating oil, and relates to the technical field of transformer aging degree monitoring of power equipment. The method comprises the following steps of: (1) measuring the three-dimensional fluorescence of transformer insulating oil with different aging degrees, and constructing a transformer insulating oil aging degree model; and (2) taking the transformer insulating oil, measuring three-dimensional fluorescence to obtain fluorescence intensity data, and judging the aging degree of the transformer insulating oil according to the transformer insulating oil aging degree model in the step (1). According to the method, whether equipment has fault hidden danger information or not can be predicted through early and real-time diagnosis results, so that the insulation performance state of the transformer insulating oil is effectively monitored, the real-time performance of detection is improved, equipment accidents are avoided, heavy loss is reduced, the reliability of equipment operation is improved, and finally, the operation safety of a power system is ensured.

The invention provides a method for processing stable and reliable roll gap measuring signals of aluminum alloy cold rolling. The method comprises the steps that in the aluminum alloy cold rolling process, alarm signals sent by a roll gap signal sensor through a transmitter are converted into switching value signals S connected into an automatic control system by a relay; and the automatic controlsystem judges the switching value signals S so as to filter false alarms, and evaluates whether the roll gap signal sensor is blocked or whether the signal deviation of the roll gap signal sensor istoo large. According to the method, the aluminum alloy cold rolling operation can be more stable and reliable.

The invention relates to automatic detection of a guide sleeve of a numerical control deep hole drilling machine, in particular to an automatic detection device and method for a guide sleeve. The automatic detection device for the guide sleeve comprises a guide sleeve body, springs and a proximity switch, wherein the outer surface of the guide sleeve body is provided with fixing brackets, sinker bars can penetrate through the centers of the fixing brackets, the springs are installed at the positions, between the fixing brackets and metal sheets, of the sinker bars, the proximity switch corresponds to one fixing bracket and is located on the same horizontal plane with the fixing bracket, and the proximity switch is connected to a PLC. The automatic detection method for the guide sleeve includes the following steps that when the guide sleeve body moves to the surface of a tube sheet, a detection ring approaches the guide sleeve body; the corresponding sinker bar connected with the detection ring approaches the proximity switch; the metal sheet at one end of the corresponding sinker bar makes contact with the proximity switch to trigger the proximity switch; the proximity switch feedsa signal back to the PLC; and the PLC detects the status of the guide sleeve body in real time. Automatic detection of the return action of the guide sleeve can be achieved, and product quality problems and equipment accidents caused by the action failure of the guide sleeve are avoided.

The invention relates to a theodolite intelligent network monitoring method and system, which belong to the technical field of the Internet of Things. The invention aims at the operation status of theodolite equipment and establishes an independent intelligent network monitoring system. The system utilizes an embedded processing platform through rich data interfaces , receive, collect and process the information collection and communication of theodolite equipment, and can carry out human-computer interaction, so that real-time online monitoring and alarming of theodolite equipment can be carried out in a more intuitive and convenient way, helping users to find early hidden dangers of theodolite equipment in time, so as to avoid major The occurrence of equipment accidents ensures the safe operation of the theodolite machine, and also reduces equipment losses and maintenance costs caused by unplanned shutdowns and crashes of theodolite equipment. Store and establish the long-term operation data of theodolite equipment, which provides reliable data for future accident inquiry and optimization design.

The invention relates to a safety interlocking device and a control method for an electrode-connected platform of an LF refining furnace, and belongs to the technical field of refining equipment outside the LF furnace. Technical solution: Under the condition that the operator does not cut off the power of the three-phase electrodes, the computer disconnects the power switch through the electrode PLC control cabinet, the three-phase electrodes are powered off, and the green indicator light is on at the same time; when the operator leaves after operating the electrodes, At an interval of 15 seconds, after the operator reaches a safe position, the three-phase electrodes are energized, and the red light of the indicator light is on at the same time. The device structure of the present invention is reasonable, and the control method is simple and practical. When the operator forgets to disconnect the high-voltage switch and enters the electrode platform, after opening the safety isolation door, the power-off interlock device will be triggered, and the high-voltage switch will be automatically disconnected, effectively avoiding the electrode from being disconnected. Arc causes personal and equipment accidents.

The invention provides a positioning device and positioning method for a cloth roller on a tobacco shred storage cabinet. By the adoption of the positioning device and the positioning method, the problem that the cloth roller is not well covered by cover cloth, and accordingly moisture and fragrance in tobacco shreds are dissipated can be solved, and the quality of the tobacco shreds is guaranteed. Meanwhile, the situation that the cover cloth gets out of an outlet of the tobacco shred storage cabinet along with finished tobacco shreds, and accordingly quality or equipment accidents are caused is avoided. The positioning device comprises a positioning support, a positioning rod and a fastening handle. When the finished tobacco shreds are covered, an operator just needs to make the cover cloth pass through the cloth roller and move to the position of the outlet of the tobacco shred storage cabinet, a square head of a rotary shaft of the cloth roller is inserted into a square hole in the positioning rod, then a square shaft in the positioning rod is inserted into an open groove of the positioning support, the fastening handle penetrates through a threaded through hole in the positioning rod and stretches into the square hole, the positioning rod and the square head of the rotary shaft are pressed tightly, the cloth roller is positioned and limited in rotation, and therefore the dimension of the pulled-out cover cloth is limited. The positioning device has the characteristics of being simple in structure, firm, durable, safe, reliable, accurate in limiting and the like and has high application value in guaranteeing the tobacco shred quality and preventing the quality or equipment accidents.

The invention relates to a multifunctional combined test valve for an SF6 gas moisture and decomposer tests to equipment of a transformer substation. The test valve comprises a three-way pin valve and an angle valve which are assembled together, wherein two valve joints of the angle valve are of right angles, the valve rod of the angle valve is of a column shape, and ventilating slots corresponding to the valve joints which are vertical to the valve rod are formed on the valve rod; and valve joints vertical to the valve rod on the angle valve are connected to the valve joints which are over against the valve rod of the pin valve and arranged on the pin valve. According to the multifunctional combined test valve, the operation of a humidity and decomposer test can be completed by once assembly and disassembly in the SF6 gas moisture and decomposer test to the equipment of the transformer substation; and power grid safety is better guaranteed in a live test, the emission amount of SF6 gas is reduced, and the air quality is improved.

The invention relates to a water-cooling electrode ring protection device for an electric arc melting furnace. The water-cooling electrode ring protection device is composed of a fixed support, safety fastening chains I / II, a high-voltage insulator, connecting plates I / II and the like. According to the water-cooling electrode ring protection device for the electric arc melting furnace, a water-cooling electrode ring is fixed to an electric arc furnace supporting arm through the fixed support, the safety fastening chains I / II, high-voltage insulator mica, the connecting plates I / II and the like, and the water-cooling electrode ring is prevented from falling into molten steel. The high-voltage insulator is composed of multiple layers of the mica capable of bearing the impact of high voltages and large currents, the high voltages and large currents generated when the electric arc furnace works are isolated from the water-cooling electrode ring, a furnace body and an operation platform, the service life of a furnace cover is prolonged, production cost is lowered, and economic benefits are improved. Personal accidents and equipment accidents caused by the explosion of the molten steel are eradicated.

The invention discloses a water penetrating cooling gas seal device, and belongs to the technical field of cooling equipment. The device comprises a composite water beam, a cross beam, a base and a gas seal nozzle assembly, the cross beam is mounted on the base, the cross beam is provided with the composite water beam, the rear end of the composite water beam is provided with a water penetrating cooling dry running through, the front end of the composite water beam is provided with multiple gas seal nozzle assemblies, the seal device is simple in structure and short in construction time, long-time production interruption cannot be caused, under the condition that a water cooling tank is not replaced, and through air spraying of gas seal nozzles, the phenomena that due to increasing of finished product speed, in order to ensure steel properties, the water pressure of the water cooling tank is increased, a large amount of cooling water is brought out by rolled metal and left in the dry run groove, remaining water in the dry run groove enables the rolled metal to be obstructed, steel stacking is caused, due to the fact that a naturally-cooled pinch roller has water, the water is brought in, a high-speed rotation high-temperature roller ring is cooled and exploded, and serious process and equipment accidents are caused can be avoided.

The invention provides a shear spring, which belongs to the field of general mechanical components and is designed for overcoming the deficiency that the prior rubber shear spring is low in strength and poor in bearing capacity. A main body of the shear spring is a cylinder which is made from nonmetal elastic materials and is provided with a hole in the middle; two metal installation claw discs are pre-embedded inside a spring body near two end faces of the spring body; the installation claw discs are provided with threaded holes for installation and use; the two installation claw discs are connected together through a safety steel wire ring; and two ends of the installation claw discs are fixed by positioning pins. The shear spring has the characteristics of convenient installation, safereliable use and long lifespan, and can be widely applied to vibrating-screening or feeding machines or other equipment with high acting force and vibration intensity in industrial and mining enterprises.

The invention relates to a handcart type switch cabinet, including a handcart, an isolation device and a linear motion mechanism, the cabinet through providing the linear motion mechanism drives the handcart to do horizontal motions, namely the isolation device and the running trail of a main shaft both follow a horizontal direction, therefore in this process no torque is acted on the main shaft, the main shaft cannot undergo rigid deformations, the performance cannot be affected, thus guarantees the accuracy of the switch closing of the isolation device, and the main shaft follows the handcart body to do horizontal motions, converting a rotational motion to a horizontal straight line motion, the running mode is very stable, thus avoiding the occurrences of safety accidents and equipment accidents.

A banner detection device, comprising a T-shaped guide rod, a controller, a bracket installed on the side of the chain of the storage cabinet, a proximity switch arranged at the top of the bracket and a fixing seat directly below the proximity switch, the T After the spring is inserted into the T-shaped guide rod, it passes through the fixed seat from bottom to top, and the lower part of the T-shaped guide rod is provided with a top that can periodically push the bottom of the T-shaped guide rod as the banner moves. A pushing device, the pushing device can make the top of the T-shaped guide rod touch the proximity switch, and the controller receives and processes the signal of the proximity switch. The invention detects the state of the banner by installing the detection device, can find the abnormality of the banner in time, and can effectively avoid quality accidents or equipment accidents; the detection device can replace manual detection, and solve the problems of high intensity and low efficiency of manual detection.