A kind of low-voltage electrical fire prevention pick-up unit
Technical field
The present invention relates to the fire detection apparatus field of low-voltage power supply system, especially a kind of device of realizing fire prevention detection by application heat-shrink tube technology.
Background technology
The fire that electrical circuit fault causes is one of topmost a kind of fire occurrence cause, how effectively to detect the important content that low-voltage electrical line fault becomes fire detection and prevention area.
We know: the electric current that 1) low-voltage supply line is carried exceeds after load current value, and supply lines can produce higher temperature, and the insulation course that even melts its appearance produces short circuit, even produces high temperature and electric arc, causes fire.2) low-voltage distribution side has many electrical connectors, when these joints service time for a long time after, may occur the situation of " loose contact " causing joint to produce high temperature and electric spark, be to cause one of reason that electrical equipment catches fire.3), in covil construction, there is a large amount of wiring lack of standardization, as: with copper cash substitute fuse, in relatively high power loop with the line of aluminum core line instead of copper heart yearn or the little line substitute specification sectional area of sectional area; The way of these even infraction of regulations lack of standardization is the key factors that cause fire.
At present, in order to detect this disaster hidden-trouble, have several technology to realize:
1) in power supply, the probes such as thermistor, temperature sensor are installed on cable, are produced alerting signal after uniform temperature being detected, it is active device that this mode exists certain defect: A, sensor, need to provide working power for it; B, monitoring point are discontinuous; C, when detected object is many, the quantity of need to popping one's head in is large, transmitted data amount also can increase, cost will increase; D, transmission link are longer, are disturbed manyly, and reliability will reduce many.
2) a kind of alloy probe sensing temperature being installed in low-voltage power supply cable changes, this alloy is arranged with cable, because this alloy is very expensive, so the cost of this cable is also very high, be not that special place is out of use, it also has a defect: can not detect the specified place that high temperature occurs.
3) optical fiber is together installed on low-voltage power supply cable, with optical fiber, as temperature sensor, as long as there is higher temperature variation, optical fiber can detect.The test side of this device is photoelectric conversion device, and its cost is not low yet, and meanwhile, once optical fiber breaks down, its maintenance is very inconvenient, needs special equipment.
For the low-voltage electrical fire that prevents the above reason to cause, in real life and work, need a kind of special fire detecting devocw, can realize the accurate detection of trouble spot, effectively prevent the generation of low-voltage electrical fire.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of low-voltage electrical fire prevention pick-up unit, can realize the accurate detection of trouble spot, and effectively preventing electric fire occurs.
The present invention solves the problems of the technologies described above with following technical scheme:
A kind of low-voltage electrical fire prevention of the present invention pick-up unit, it mainly detects cable 10, capacitor C and multi-way intelligence detecting device 11 by least one group and forms.
Described detection cable 10 is flat profile, heat-shrink tube 1, two wires 2 and isolation plastics 3, consists of.Two wires 2 are arranged in isolation plastic tube 3 side by side, between two wires 2, leave cavity 4, and isolation plastic tube 3 is wrapped with heat-shrink tube 1.
Described multi-way intelligence detecting device 11 is connected to every group of one end of detecting cable 10, and every group of other end connection capacitor C that detects cable 10 is connected to form loop.
Between two inner sides that the isolation plastic tube 3 of described detection cable 10 contacts with metal wire 2 and two wires 2, be arranged with projection 14.
The present invention is by adopting heat-shrinkable T bush that cost performance is higher as thermal sensor, realize passive, the configuration continuously of thermal sensor, monitoring point can be arranged according to actual needs, detected object can be point, face, line, be applicable to different supply lines, plug, controller switching equipment and various electrical appliance, realized the accurate detection to trouble spot, cheap, simple, safe and reliable, can carry out fault forecast, effectively prevent the generation of electrical fire.
Accompanying drawing explanation
Fig. 1 is testing circuit schematic diagram of the present invention.
Fig. 2 is detection cable cross sectional representation of the present invention.
Fig. 3 is detection cable profile schematic diagram of the present invention.
Fig. 4 is detection schematic diagram of the present invention.
1---heat-shrink tube
2---metal wire
3---isolation plastic tube
4---cavity
5---busbar
6---fuse
7---contactor
8---isolating switch
9---service cable
10---detect cable
11---multi-way intelligence detecting device
12---electric wire (cable) joint
13---socket
14---projection
C---electric capacity
Embodiment
Below in conjunction with accompanying drawing, the invention will be further described:
Low-voltage electrical fire prevention pick-up unit of the present invention, it mainly detects cable 10, capacitor C and multi-way intelligence detecting device 11 by least one group and forms.Multi-way intelligence detecting device 11 is connected to every group of one end of detecting cable 10, and every group of other end connection capacitor C that detects cable 10 is connected to form loop.Multi-way intelligence detecting device 11 can send AC signal and return via capacitor C, thereby detect whole piece, whether detects cable in normal condition.As shown in Figure 1.
Detecting cable 10 is flat profile, as shown in Figures 2 and 3.Detecting cable 10 is comprised of heat-shrink tube 1, metal wire 2 and isolation plastic tube 3.As shown in Figure 2.Metal wire 2 has two, be arranged in parallel and be arranged in isolation plastic tube 3, and the isolation with the tube wall of heat-shrink tube 1 by 3 realizations of isolation plastic tube, in the tube chamber of isolation plastic tube 3, being reserved with certain cavity 4 two metal tubes 2 are separated, isolation plastic tube 3 is wrapped with heat-shrink tube 1.
In order realizing, to make heat-shrink tube 1 realize better compression effectiveness, between two inner sides that can contact with metal wire at isolation plastic tube 3 and two wires 2, to be arranged with projection 14.When heat-shrink tube 1 is experienced after high temperature, produce convergent force compressing projection 14 and make two wires 2 contacts, and form loop between multi-way intelligence detecting device 11, multi-way intelligence detecting device 11 just can detect loop resistance value, thereby judges this short dot position.
The crust that detects cable 10 adopts heat-shrink tube.Heat-shrink tube is a kind of special polyolefin material thermal contraction casing tube, also has and is called EVA material, and it has low-temperature shrink, soft fire-retardant, insulation corrosion protection function.Heat-shrink tube is in the insulation protection of various wire harness, solder joint, inductance, in antirust, the corrosion protection of metal tube, rod, is used widely.
The principle of work of this device is as follows:
As shown in Figure 4, can be according to the actual requirements, select the flat horizontal surface that detects cable 10 to be arranged in the various electrical equipments that may produce high temperature, electric spark such as busbar 5, fuse 6, isolating switch 7, contactor 8, service cable 9, electric wire (cable) joint 12, socket 13.After certain wherein reaches certain temperature (as 100 ℃), the crust (heat-shrink tube 1) that detects cable 10 shrinks (shrinkage factor can reach 30%-50%) inwards, oppress two wires 2 move toward one another and contact, form the phenomenon of partial short-circuit, be arranged on one end multi-way intelligence detecting device 11 that detects cable 10 and will detect the metal wire 2 " short circuit phenomenon " detecting in cable 10 at once, produce alerting signal simultaneously and allow other smart machines carry out to cut off the electricity supply the preparation of power supply.Because heat-shrink tube 1 operating temperature is 100 ℃ of left and right, lower than the kindling point of many materials.When multi-way intelligence detecting device 11 has detected " short circuit " signal and produces, by intelligent computation and demonstrate lap-joint to the distance of multi-way intelligence detecting device 11, facilitate maintainer to find the place that produces fault, thereby greatly reduced the occurrence probability of fire.
Described multi-way intelligence detecting device 11 can adopt the detecting device of prior art, and its Computing Principle that detects distance is: the resistance R of long lead and line length L, cross-sectional area S, linear resistivity ρ have following relational expression: R=ρ (L/S).In the situation of known ρ, S, measure after resistance value, can calculate the value of L, thereby judge the distance of " short circuit ".Intelligent detector can be set to " timesharing detection ", so just can " simultaneously " detect the input signal of multichannel fireproof cable, once detect after " short circuit " signal, calculate short-circuit signal and where occur in, and superior sends the information such as warning at once.
If after detecting cable action or break down, fault place can be cut, access the detection cable that another root is new, connect metal wire wherein and bandage and can recover measuring ability, safeguard very convenient.
This device can connect many groups and detect cable, by the mode of " the timesharing detection " of multi-way intelligence detector is set, and measuring ability when the many groups of realization detect cable.
The present invention is by adopting heat-shrinkable T bush that cost performance is higher as thermal sensor, can realize when many groups detect cable and detecting, be applicable to different supply lines, plug, controller switching equipment and various electrical appliance, realized the accurate detection to trouble spot, cheap, simple, safe and reliable, effectively prevented the generation of low-voltage electrical fire.