CN2247896Y - Automatic power interruption type water boiling heater for vacuum bottle - Google Patents

Abstract

The utility model relates to an automatic power interruption type water boiling heater for a vacuum bottle. Controlled silicon is used to be served as a contactless switch to control an electric heater R< L >. The A end and the B end are connected with the commercial power; the trigger current path of the controlled silicon KS is the positive pole of C2-T2-G-C-e-negative pole of C2. The resistance value of the thermistor Rt continuously rises up along with the water temperature rise, which brings on the continuous rise of the Vce voltage of a triode BG, and the Vce+VT< 2G > voltage also rises up. When the voltage reaches a threshold voltage conducted by a series circuit composed of voltage V3, voltage V4, and a photocoupler U, the resistance value between output terminals 3, 4 of the photocoupler U is lowered; the emitter junction voltage of the triode BG is short-circuited to make the triode BG cut-off; the controlled silicon KS is switched off due to trigger current loss, and then the electric heater R< L > loses the electricity to stop heating.

Description

Thermos flask auto-cut-off type water boiler

The utility model relates to the circuit that a kind of noncontacting switch of forming with bidirectional triode thyristor is controlled electric heater.

The switch that in the prior art, is used for " thermos flask auto-cut-off type water boiler " is for touching switch.What use as this series products of China's " electronics newspaper " 94 year 28 phase introduction promptly is the sensitive switch that the contact is arranged.The easy scaling loss of contact switch contact causes Control Failure, and this series products is not durable.

The purpose of this utility model provides a kind ofly makes noncontacting switch with bidirectional triode thyristor, replaces the contact switch of this product, thereby improves the durability of this product.

The circuit of the utility model " thermos flask auto-cut-off type water boiler " is made up of major loop and control loop.Major loop is made noncontacting switch and electric heater R with bidirectional triode thyristor KS _LSeries connection is with the break-make control R of KS _LIn the control loop, use C ₁, C ₂, V ₁And V ₂Form the capacitance current-limiting type rectification circuit, for KS provides trigger current; With triode BG, potentiometer R _PForm the control circuit of KS trigger current with the thermistor Rt (cooling-water temperature sensor) of positive temperature coefficient.The Lu Jingwei of KS trigger current: C ₂Positive pole → T ₂→ G → C → e → C ₂Negative pole.R _PWith the base loop that inserts BG after Rt is in parallel, Rt resistance increase when water temperature raises, the Vce value of BG increases.Because of Rt and BG parameter have discreteness, admittedly use R _PThe Vce magnitude of voltage of BG when adjusting boiling water; In the technical solution of the present utility model, use voltage-stabiliser tube V ₃, Light-Emitting Diode V ₄And photoelectrical coupler U string is formed the control circuit of BG.V ₃, V ₄Connect V with the input 1,2 of U ₃Negative pole meet C ₂Positive pole, the terminals 2,4 of U are connected with the emitter e of BG, and the terminals 3 of U are connected with the base stage b of BG.Be added in by V ₃, V ₄The voltage at the series circuit two ends of forming with U equals Vce+VT _2G, when water was heated to boiling point, Vce voltage reached a definite value because of the rising of Rt, at this moment, and Vce+VT _2GVoltage reaches by V ₃, V ₄The threshold voltage of the series circuit conducting of forming with U, V ₃, V ₄, the U conducting, 3,4 of the outputs of optical coupler U transfer low resistance to by high value.The emitter junction voltage of BG is by short circuit, and BG ends.KS turn-offs R because of losing trigger current _LStop heating.V ₄Double as water boils and shows usefulness.

Because this circuit has adopted the control mode to triode BG emitter junction voltage, when 3, the 4 end points low resistance of U, make the emitter junction voltage short circuit of BG, BG is by reliable, makes the KS can reliable turn-off after water boils, and is not subjected to power-supply fluctuation and other factor affecting and causes the repetition conducting of KS.This circuit is without integrated package simultaneously, and element is few, cost is low.

Below in conjunction with the drawings and specific embodiments the utility model is described in detail:

Be illustrated as the circuit diagram of the utility model " thermos flask auto-cut-off type water boiler ".

The circuit of this figure described " thermos flask auto-cut-off type water boiler " comprises:

1, with bidirectional triode thyristor KS and electric heater R _LThe major loop that composes in series.Switching with KS is implemented R _LAdd thermal control.

2, the power supply of bidirectional triode thyristor KS control loop: use C ₁, C ₂, V ₁, V ₂Form the capacitance current-limiting type rectification circuit, A, B are input, connect the 220V civil power, C ₂Two ends output DC stream.C ₂Positive pole meet the T of KS ₂The utmost point, C ₂Negative pole connect the e utmost point of triode BG, adopt negative triggering mode.

3, the control circuit of bidirectional triode thyristor KS trigger current.With triode BG, thermistor Re, adjustable resistance R _PForm Rt, R _PIn parallel.During the BG conducting, KS obtains trigger current conducting, R _LGet electric heating.The path of trigger current is: C ₂Positive pole → T ₂→ G → C → e → C ₂Negative pole.When BG ended, KS just lost trigger current, turn-offs R voluntarily when the AC power zero passage _LDead electricity stops heating.

4, the control circuit of triode BG operating state is used voltage-stabiliser tube V ₃, Light-Emitting Diode V ₄U is composed in series with optical coupler.V wherein ₃Negative pole and capacitor C ₂Anodal connection, V ₄Negative pole connect the terminals 1 of U, the terminals 2 of U meet C ₂Negative pole, the terminals 2,4 of U are connected with the emitter e of BG, the terminals 3 of U are connected with the base stage b of BG.

This circuit is worked like this: water is heated process: after A, B termination are gone into the 220V civil power, by C ₁The rectifier power source of current limliting makes KS obtain trigger current and conducting, R _LMust electric water be heated.Trigger current path: C ₂Positive pole → T ₂→ G → C → e → C ₂Negative pole.At this moment, because of water temperature does not arrive boiling point, the Rt resistance is lower, and Vce voltage is lower than definite value, Vce+VT _2GVoltage also is lower than by V ₃, V ₄, the series circuit formed of U threshold voltage, V ₃, V ₄, not conducting of U, so output the 3, the 4th of U, high value, BG emitter junction voltage is unaffected, BG conducting, KS conducting.When water was heated boiling point, thermistor Rt was raised to a definite value, and Vce voltage also is raised to a definite value, at this moment, and Vce+VT _2GVoltage reaches by V ₃, V ₄, the series circuit formed of U threshold voltage, so V ₃, V ₄The U conducting, 3,4 of optical coupler outputs become low resistance by high value, make the short circuit of BG emitter junction voltage, and BG ends, and KS thereby lose trigger current automatically shuts down R when the AC power zero crossing _LStop heating.

In the exemplary embodiments of this circuit, capacitor C ₁, C ₂Parameter is respectively 0.47 μ F/450V, and 220 μ F/16V, resistance R P are 220K/1W, and Rt is 6800 (25 ℃), and V1, V2 are 1N4007, and V3 is 2CW9, and V4 is LD707, and V is CD-M, and BG is 3DG6C, and KS is 6A/600V, and RL is 700W.

Claims (1)

1, thermos flask auto-cut-off type water boiler is made noncontacting switch with bidirectional triode thyristor KS and is connected with electric heater, with the switching control R of KS _L, in the control loop, use C ₁, C ₂, V ₁, V ₂Form the capacitance current-limiting type rectification circuit and provide trigger current for KS; With triode BG, thermistor Rt variable resistance R _PThe negative trigger control circuit of forming KS; Trigger current path: C ₂Positive pole → T ₂→ G → C → e → C ₂Negative pole; It is characterized in that: the emitter junction loop at triode BG is inserted by voltage-stabiliser tube V ₃, Light-Emitting Diode V ₄With the control circuit that optical coupler U is composed in series, control triode BG operating state; Wherein, V ₃Negative pole meet C ₂Positive pole, the terminals 2,4 of U are connected with the BG emitter e, and the terminals 3 of U are connected with the base stage b of BG; When the water end was heated to boiling point, thermistor Rt resistance was lower, thereby Vce voltage is lower than definite value, Vce+VT _2GVoltage also is lower than by V ₃, V ₄, the series circuit threshold voltage formed of U, this moment V ₃, V ₄, not conducting of U, thereby the output 3,4 of U is high value, BG emitter junction voltage is unaffected, the BG conducting; When water was heated to boiling point, thermistor Rt was raised to a definite value, at this moment Vce+VT _2GVoltage reaches by V ₃, V ₄, the series circuit threshold voltage formed of U, so V ₃, V ₄With the U conducting, 3,4 of the outputs of optical coupler U become low resistance by high value, make the short circuit of BG emitter junction voltage, and BG ends, and KS thereby lose trigger current turn-offs R voluntarily when the AC power zero crossing _LStop heating " thermos flask auto-cut-off type water boiler " and promptly realized the boil function of automatic stop of water.