CN2130271Y

CN2130271Y - Temp.-controlled protector

Info

Publication number: CN2130271Y
Application number: CN 92228790
Authority: CN
Inventors: 许顺峰
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-07-31
Filing date: 1992-07-31
Publication date: 1993-04-21
Anticipated expiration: 2002-07-31

Abstract

The utility model discloses a temp. -controlled protector, belonging to an electric appliance for the automatic control and the protection of electricity. Stepless regulation and control can be carried out on the setting temp. of an electric heater by the temp. -controlled protector; in addition, the temp. -controlled protector which has the functions of short-circuit protection, broken-circuit protection, and contingency protection can achieve the purpose of energy saving. The utility model is characterized in that a monostable circuit is controlled by a temp. control circuit, a zero crossing switch and a protective circuit through an OR gate; the monostable circuit controls the on-off state of a bidirectional thyristor, and simultaneously controls loads connected in series with the bidirectional thyristor. The utility model is suitable for the temp. control and the protection of various electric heaters.

Description

Temp.-controlled protector

The utility model is a kind of temperature control and protection instrument, belongs to the electric automatic control instrument.

Be used for the temperature-control circuit of electric heaters such as electric blanket, be mainly two kinds of bimetallic strip contact-making switch and diode half-wave rectification at present.The bimetallic strip contact-making switch utilizes the difference of different metal expansion coefficient to control the break-make of power supply, and its volume is big, and sensitivity is low, produces electric spark during the break-make power supply, has unsafe factor, and its usable range is restricted.Though diode half-wave rectification circuit is simple, its temperature is unadjustable, and its usable range also is restricted.The equal unprotect function of above in addition two kinds of circuit.

At the shortcoming of present temperature controller, it is electrodeless adjustable that the designed instrument of the utility model becomes temperature control, and have short-circuit protection, open circuit protection, mishap (causing fire as the NOT-circuit fault) defencive function and power saving function.

The purpose of this utility model is to realize like this.Thermistor is closely contacted with the object of being heated, in a bit of time △ T after the energized (being generally about one-period), delay circuit (5) makes the inverting input voltage of voltage comparator (6) be higher than in-phase input end voltage (this is comparative voltage), makes voltage comparator (6) output low level.The temperature of object is lower than the control temperature that sets if heated this moment, and the inverting input voltage of electric bridge and voltage comparator (1) is higher than in-phase input end voltage, and its output also is low level.In one-period, zero passage switch (2) will be exported low level twice.When (1), (2), (6) all during output low level, or door (8) output low level, the trigger end of monostable circuit (9) is input as low level, and it is output as high level, and it triggers controllable silicon (11) conducting by current-limiting resistance, makes load R _LWork, thereby to the object heating of being heated.Have electric current to pass through in the main circuit this moment, the sampled filtering shaping circuit of this electric current (3) is taken a sample, be input to the in-phase input end of voltage comparator (4), compare with inverting input voltage (this is a comparative voltage), make (4) be output as square wave, its high level is delayed time through delay circuit (5), after power connection surpasses △ T, delay circuit (5) is still exported high level, make voltage comparator (6) be output as low level, thereby make controllable silicon continue conducting, heating object obtains continuing to heat.With variation of temperature, the resistance of thermistor also changes, two input terminal voltages of voltage comparator (1) are changed, when the heating object temperature rises to setting value, the output of voltage comparator (1) is reversed, the high level of its output by or door (8) to make the input end of monostable circuit (9) be high level, it is output as low level, thereby controllable silicon (11) is turn-offed, stop heating.Because no current in the main circuit makes the output of sampling filtering shaping circuit (3) voltage comparator (4) be low level, but the high level of voltage comparator (1) output makes the output of voltage comparator (6) still be low level by delay circuit (5).Reduction with temperature, the output of voltage comparator (1) is reversed once more, output low level, because the effect of delay circuit (5), voltage comparator (6) is output low level still, thereby when zero passage switch zero passage output low level, can trigger controllable silicon (11) once more, make the main circuit conducting, heating object is heated.Change the variable resistor resistance of brachium pontis, can change voltage comparator (1) the required temperature (design temperature) of counter-rotating takes place.When voltage comparator (1) band hysteresis loop, change its positive feedback resistor value, then can change bound poor of design temperature.Make the electrodeless adjustable purpose of design temperature thereby reach, again because the effective load R that controlled of science _LThe break-make of middle electric current, thus reach purpose of energy saving.

When circuit was short-circuited, the electric current in the main circuit increased, thereby makes fuse blows, cut off circuit, played the short-circuit protection effect.

When circuit takes place (mostly to be load R _L) when opening circuit, if this moment energized still, when the place of opening circuit virtual connection takes place touches, can produce electric spark, unsafe factor (electric blanket fire many so faults cause) appears.And the utility model is when energized, if when voltage comparator (1) output high level the generation open circuit fault, so the time controllable silicon be in off state, so electric spark can not occur.If comparer (1) is when being output as low level; open circuit fault takes place; make no current in the main circuit; current sampling filtering integer circuit (3) is exported no signal; the homophase of voltage comparator (4) is input as low level; its output also is low level, and after the △ T time, delay circuit (5) is with output low level; make voltage comparator (6) be output as high level; the warning of triggering sound light alarming circuit makes simultaneously or door (8) is output as high level, and monostable circuit is output as low level; controllable silicon is turn-offed; both made the virtual connection of the place's of opening circuit generation after this touch phenomenon and turn-offed, and also electric spark can not occur, thereby play the open circuit protection effect because of controllable silicon.

When the accident of meeting accident; as NOT-circuit reason fire; cause that the heating object local temperature raises, can make the resistance of certain thermistor in the brachium pontis that bigger variation takes place, although the change in resistance of other thermistor is little; also make the total resistance value of the thermistor of series connection that bigger variation takes place; (1 reverses, and exports high level, thereby controllable silicon is turn-offed to make voltage comparator; cut off main circuit, play the mishap protective effect.

Fig. 1 is the utility model schematic diagram.R wherein _LBe load.1.～8. be the pin sequence number of 555 time base circuits.The general available light emitting diode music-integrating block series connection of sound light alarming circuit promotes power tube by music-integrating block and drives sounder, and the output of voltage comparator (6) is as the operating voltage or the triggering level of warning circuit.Fig. 2 is a mains waveform.Fig. 3 is the output waveform of electric bridge and voltage comparator (1), and the A point is its output terminal.Fig. 4 is the output waveform of zero passage switch (2), and the B point is that its output terminal Fig. 5 is the output waveform of voltage comparator (4), and the C point is its output terminal.Fig. 6 is the output waveform of voltage comparator (6), and the D point is its output terminal.Fig. 7 be or the door (8) output waveform, E is its output terminal.Fig. 8 is the output waveform of monostable circuit (9), and F is its output terminal.Fig. 9 is a load R both end voltage waveform.Among Fig. 2～Fig. 9, T is the civil power cycle.0～2T and 4T～4.75T be the each point waveform when heating, and 2T～4T is the each point waveform during for insulation, and open circuit fault takes place when establishing 4.75T, the waveform of each point during open circuit protection behind the 5.75T.

Enforcement of the present utility model can be arranged in each thermistor on the heating object uniformly, and load R is fully contacted with heating object.And the part beyond thermistor and the load is installed in the box.

Claims

1; a kind of electronic temperature control protector; be by stabilized voltage supply+Ec; electric bridge and voltage comparator [1]; zero passage switch [2]; current sampling filtering shaping circuit [3]; voltage comparator [4]; [6]; delay circuit [5]; sound light alarming circuit [7]; or door [8]; monostable circuit [9]; fuse [10]; part such as bidirectional triode thyristor [11] is formed; the fuse [10] that is characterised in that of the present utility model; bidirectional triode thyristor [11] is composed in series main circuit with load R; voltage comparator [1]; zero passage switch [2]; the output terminal of voltage comparator [6] by or the trigger end of door [8] and monostable circuit [9] link; the output terminal of monostable circuit [9] links by the gate pole of current-limiting resistance and controllable silicon [11]; the output terminal of current sampling filtering integer circuit [3] and the in-phase end of voltage comparator link; voltage comparator [1]; [4] output terminal and stabilized voltage supply+Ec link by the end of oppisite phase of delay circuit [5] with voltage comparator [6]; sound light alarming circuit [7] links with the output terminal of voltage comparator [6], and the electric routing stabilization pressuring power+Ec beyond the main circuit provides operating voltage.

2, temperature-control protector according to claim 1 is characterized in that in the brachium pontis of electric bridge and voltage comparator (1), and it is variable resistor that a brachium pontis is arranged, and a brachium pontis is one or more thermistor series connection.

3,, it is characterized in that the comparer of electric bridge and voltage comparator (1), also with the comparer of hysteresis loop according to claim 1,2 described temperature-control protector.