CS206705B1 - Connexion for control of boiler thermostat by external temperature - Google Patents

Description

(54) Connection for boiler thermostat control by outdoor temperature

The invention relates to a circuit for the control of a boiler thermostat by an outdoor temperature based on the conversion of physical quantities into electrical quantities with subsequent processing in a simple electronic circuit.

In many objects heated by high-fuel boilers, the heating mode is controlled by the boiler operator, ie a heater or a room thermostat or thermoregulation valves mounted on radiators. These are schools, kindergartens, nurseries, health facilities, etc., where the indicated methods of regulation have a number of disadvantages. When operating the boiler with a heater, constant operation is required to determine and maintain the heating mode, which requires labor.

The control of the heating mode by the room thermostat is inaccurate for larger buildings and does not perfectly describe the thermal comfort in the whole building.

The relatively perfect way of regulating the heat consumption of radiators with thermoregulation valves is demanding for the operator when changing the heating mode and completely eliminates the possibility of automatic change when the object is unoccupied.

There is a known method of determining the heating mode depending on the outdoor temperature, which would eliminate these drawbacks in said objects, but the controllers produced so far are intended to continuously control the actuator which determines the flow rate of the heating medium according to the outdoor temperature. This controller is for the solved purpose, where two-position, costly and expensive regulation is sufficient.

The above-mentioned disadvantages are solved by the connection for controlling the boiler thermostat by the outdoor temperature, which is based on the fact that the thermistor measuring the heating water temperature in series with the pair measuring the outdoor temperature forms a bridge. element is a relay.

Particular embodiments of the invention shown in the diagram of Fig. 1. Here the measuring bridge consisting of thermistors those t _2, the resistors Ri, _R2, R3 and potentiometer P and P _2, i.e., the first thermistor senses the temperature of water in the boiler and the second thermistor t ₂ outdoor temperature. The first potentiometer Pi sets the temperature curve of the object and the second pbtemoiometer sets the night temperature drop, bridged by the switch V _1; such as a timer. The bridge is supplied with alternating current from a separate winding of the transformer, eliminating the need to distinguish the polarity of the output signal. The bridge output is only connected via capacitor C ₄ based on the first transistor T ₄ . In the collector of the third transistor T ₃ is connected relay Rej., Which is an executive element of the controller. The diode in the emitter, the third transistor T _3, adjusts its switching mode. '

Fig. 3 is a graphical representation of the function performed by the controller, the dependence of the heating water temperature on the outside temperature. Due to the non-linearity of the thermistors, the waveform is non-linear, which is preferably used to determine the lower limit of the heating water temperature with respect to the boiler corrosion during flue gas condensation.

Fig. 4 shows a block functional diagram of the controller in relation to the controlled one. element, which shows · thermistor heating water 1, thermistor outdoor temperature,

2, measuring bridge 3, amplifier 5, relay 6 and burner solenoid 4.

Finally, FIG. 2 shows the resistance curve of the thermistors used as a function of temperature.

Claims (1)

SUBJECT Connected to control the boiler thermostat by the outside temperature, characterized in that the first thermistor (¾) for measuring the temperature of the heating water connected in series with the pair of the first resistor and the second thermistor (R _1; t ₂ ) for measuring the out function; If the water temperature in the boiler is lower than required, the resistance of the first thermistor t ₁ increases ₍ the current at the output of the bridge and relay Rei drops out. Despite the break contacts the boiler burner solenoid closes). ti, the current at the bridge output increases and the relay Re _t pulls in. This interrupts the current to the boiler burner solenoid and goes out The potentiometer Pi is used to set the boiler water temperature at which Re ₄ relays, ie the water temperature in the heating system. The second thermistor t ₂ is connected to the first thermistor t ₄ in series and senses the outside temperature Resistor R ₄ parallel to the second thermistor t ₂ adjusts the change in resistance of the second thermistor t ₂ as a function of the outside temperature so that it is of the order of magnitude. thermistor t _P The lower the outdoor temperature, the greater the resistance of the pair R1>>2 and the resistance of the first thermistor must be to balance the bridge the lower the heating water temperature is. INVENTION metalliferous temperature together with the resistor (R ₂₎ (R 3) and a potentiometer (Ρχ) bridge, whose output is connected to a three-stage amplifier composed of the transistors (T ^), (T ₂₎ (T ₃₎ whose end executive element is relay (Rej).