JPH0134046Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a temperature controller for a reduced pressure steam type hot water generator used for hot water supply and space heating.

A medium-sized reduced-pressure steam hot water generator that can be used for both hot water supply and space heating has a heat exchanger for hot water supply and a heat exchanger for space heating, and the temperature control for both is as follows.
Generally, this is done by adjusting the calorific value of the combustor so that the heating medium temperature matches the set temperature. The amount of heat generated can also be adjusted based on the outlet temperature of the hot water supply heat exchanger (hot water supply temperature). Furthermore, as this type of hot water generator continues to operate, the degree of vacuum gradually decreases and the thermal efficiency deteriorates, so it becomes necessary to bleed air to increase the degree of vacuum. The timing for performing air extraction is selected based on the fact that the difference between the heat medium temperature and the hot water supply temperature (or heating temperature) reaches a certain value or more. Furthermore, in order to prevent freezing in cold weather, the hot water generator is operated at the lower limit of the set temperature range.

However, conventional temperature regulators cannot meet the above-mentioned complex control requirements, and require various complex adjustments to be made on the hot water generator side. In particular, anti-freezing operation is performed at the lowest set temperature, so there is a drawback that the differential is small and the engine starts and stops repeatedly at short intervals, and it is also impossible to determine whether or not it is freezing operation.

The purpose of this invention is to provide a temperature controller for a vacuum steam hot water generator that is equipped with the above-mentioned functions required of a vacuum steam hot water generator and that also enables stable antifreeze operation. There is.

Next, one embodiment of this invention will be explained with reference to the drawings. The temperature regulator of the reduced pressure steam hot water generator of this invention consists of a main controller A and a sub-controller B. Main controller A
has a power transformer 1, a rectifier circuit 2 for full-wave rectification of its secondary output, and a constant voltage circuit 3 for making the rectified output a constant voltage, and the output of the constant voltage circuit 3 is composed of a microcomputer. The signal is supplied to the arithmetic control section 4 and a linearization circuit 11, which will be described later. The calculation control unit 4 uses the temperature setting signal given from the temperature setting circuit 5 as a set value, and performs a predetermined calculation using the heating temperature signal, hot water supply temperature signal, and heating medium temperature signal supplied via the linearization circuit 11 as process variables. and supplies an output based on the result of this calculation to the relay drive circuit 6. Further, the calculation control unit 4 outputs a signal to the display drive circuit 7 in accordance with the operation of the display changeover switch SW2,
The value of the input temperature signal is digitally displayed on the display 8 together with its mode. The functions of such arithmetic and control section 4 are basically the same as those used in ordinary digital temperature controllers, so detailed explanation thereof will be omitted.

A variable resistor VR1 for setting the hot water temperature and a variable resistor VR2 for setting the heating medium temperature are connected to the temperature setting circuit 5 via a switch SW1-1, respectively, and when one of them is set to a desired control mode. It is becoming more and more of a choice. In addition, the switch SW1-2 that is linked with the switch SW1-1 is
As a process variable supplied to the calculation control unit 4,
When the hot water supply temperature setting variable resistor VR1 is selected, the detected value of the hot water supply temperature is selected, and when the heating medium temperature setting variable resistor VR2 is selected, the detected value of the heating medium temperature is selected.

If the two mutually interlocking switches SW3-1 and SW3-2 are in the "operating" position, the relay drive circuit 6 will operate only the relay K1 according to the signal output from the calculation control unit 4 if the heat demand is small. of,
Also, if the heat demand is large, relays K1 and K2 are activated. Relays K1 and K2 are for controlling the combustion state (calorific value) of the reduced pressure steam hot water generator that is the controlled object, and relay K1 corresponds to the low combustion state, and relay K2 corresponds to the high combustion state. There is. If the switches SW3-1 and SW3-2 are in the "off" position, no operation will be performed. Further, when the switches SW3-1 and SW3-2 are switched to the "freeze" position, the relay K1 and the lamp L2 for displaying the antifreeze operation are connected to the output terminal of the relay drive circuit 6. Therefore, if a signal similar to that described above is supplied from the arithmetic control section 4 to the relay drive circuit 6 in this state, the relay K1 is activated and at the same time the lamp L2 is lit to indicate that the antifreeze operation is being performed.

Further, the switch SW3-3, which is interlocked with the switches SW3-1 and SW3-2, transmits the hot water supply temperature signal or heating medium temperature signal selected by the switch SW1-2 to the calculation control unit 4 when it is in the "operation" position. However, when switched to the "freeze" position,
Regardless of the position of the switch SW1-2, the heat medium temperature signal is selected and transmitted to the calculation control section 4. Furthermore, when the switches SW3-1, SW3-2, and SW3-3 are switched to the "freeze" position, the calculation control unit 4
Fixed set values for antifreeze operation that are preset in the temperature setting circuit 5 (for example, ON point 5°C,
The same control as above is performed by selecting the off point (60° C.) and comparing the input heating medium temperature signal with this fixed set value.

Next, subcontroller B will be explained.
The linearization circuit 11 includes a thermistor TM1 for detecting heat medium temperature and a thermistor TM1 for detecting hot water temperature.
The outputs of TM2 and thermistor TM3 for detecting heat medium temperature are linearized to output a heating temperature signal, a hot water supply temperature signal, and a heat medium temperature signal. The rectifier circuit 2 and the constant voltage circuit 13 supply power supply current to the temperature comparison circuits 14, 15 and other circuits. The first temperature comparison circuit 14 detects the difference between the heating temperature or the hot water supply temperature and the heating medium temperature based on the heating temperature signal or the hot water supply temperature signal and the heating medium temperature signal taken out from the linearization circuit 11, An output is output when this difference exceeds a reference value. Variable resistor VR3 is for setting this reference value, and switch SW
4 selects either the heating temperature signal or the hot water supply temperature signal as the signal supplied to the first temperature comparison circuit 14 .

Further, the second temperature comparison circuit 15 compares the heating medium temperature detected as a heating medium temperature signal with a predetermined reference temperature (for example, 75° C.), and outputs an output when the temperature is equal to or higher than the reference temperature. The AND circuit 17 provides an H level output to the relay drive circuit 18 when the outputs of the first temperature comparison circuit 14 and the second temperature comparison circuit 15 are both at the H level. While driving relay K4, the bleed air alarm lamp L1 is turned on.

Furthermore, the heating medium temperature signal taken out from the linearization circuit 11 is also supplied to the high temperature detection circuit 16.
This high temperature detection circuit 16 activates the relay drive circuit 18 when it detects that the heat medium temperature exceeds a preset high limit temperature (usually 90°C to 95°C).
A high limit signal is sent to the relay K3, which activates the relay K3. Normally open contact K of this relay K3
3-1 is turned on when relay K3 is activated,
Outputs high limit signal. Also, normally closed contact K3
-2 is the normally closed contact K4-1 of relay K4 and switch SW1-3 (this is switch SW1-1,
(interlocked with SW1-2) constitutes a bleed air alarm output circuit. Here, it is assumed that an air bleed alarm signal is issued when terminal #17 and terminal #18 are opened.

Assume that switches SW1-3 are now in the "heat medium" position. In this state, one end of the contact K3-2 is disconnected from the #18 terminal, so regardless of whether this contact K3-2 is open or closed, the contact K3-2 is disconnected from the #18 terminal.
#17 terminal and #18 when 4-1 turns off
The terminals are opened and a bleed alarm signal is issued. Further, when relay K3 operates, contact K3-1 is turned on and a high limit signal is output. Next, when switch SW1-3 is in the "hot water supply" position,
Contacts K3-2 and K4-1 are connected in parallel with each other, and a bleed alarm signal is issued only when both are turned off. In other words, when the heating medium temperature is selected as the control target, the bleed air alarm signal is output when the heating medium temperature is above the set value and the temperature difference between the heating medium temperature and the hot water supply temperature or heating temperature is above the set value. In addition, in a state where the hot water supply temperature is selected as the control target, an air bleed alarm signal is issued when the above condition and the condition that the heating medium temperature exceeds the high limit value are simultaneously satisfied.

In general, in a control mode based on hot water temperature, the goal of this control is to always bring the hot water temperature as close to the set value as possible, so if a large amount of hot water is supplied, the heating medium temperature will significantly exceed the hot water temperature. It may happen that the difference exceeds the set value for the bleed alarm. However, in the above configuration, even if this air bleed alarm condition is satisfied, the air bleed alarm is not issued unless the heat medium temperature exceeds a high limit value (usually 90° C. to 95° C.). Further, if the heat medium temperature exceeds the high limit value, a high limit signal is issued in addition to the bleed air alarm, so safety can also be ensured.

As described above, according to this invention, in controlling the reduced pressure steam type hot water generator, it is possible to arbitrarily select control based on the hot water temperature or control based on the heating medium temperature. In addition, when control based on hot water temperature is selected, the bleed air alarm will not be issued unless the heating medium temperature exceeds the high limit value, so there will be no inconvenience such as a bleed air alarm being issued by mistake when a large amount of hot water is being supplied. do not have. Furthermore, by selecting the antifreeze operation with the switch, even if the hot water temperature is selected as the control target, the heating medium temperature is automatically selected, which simplifies the operation. Furthermore, when switching to antifreeze operation, the set temperature is fixed at a desired value (for example, on point 5° C., off point 60° C.), so the number of starts and stops is reduced, resulting in an energy saving effect.

[Brief explanation of the drawing]

The figure is a block diagram showing the structure of a temperature regulator for a reduced pressure steam type hot water generator according to an embodiment of the invention. A... Main controller, B... Sub controller, 1... Power transformer, 4... Arithmetic control section, 5... Temperature setting circuit, 6... Relay circuit, 7
... Display drive circuit, 8 ... Display device, 11 ... Linearization circuit, 14, 15 ... Temperature comparison circuit, 1
6...High temperature detection circuit, 18...Relay drive circuit,
K1, K2, K3, K4...Relay.

Claims (1)

[Scope of utility model registration request] In a temperature controller for a reduced pressure steam hot water generator equipped with a hot water supply heat exchanger and a heating heat exchanger, a heating medium temperature signal indicating the heating medium temperature and a hot water supply temperature indicating the outlet temperature of the hot water supply heat exchanger. a first switch means for selecting one of the signals; and an arithmetic control unit that compares the selected heating medium temperature signal or hot water temperature signal with a variable set value and outputs a control output when the temperature signal is lower than the variable set value. and a second switch means for selecting either the hot water supply temperature or the heating temperature signal indicating the outlet temperature of the heating heat exchanger, and converting the selected hot water supply temperature signal or the heating temperature signal into the heating medium temperature signal. a first temperature comparison circuit that outputs an output when the difference between the two is greater than or equal to a set value; a second temperature comparison circuit that produces an output when the heating medium temperature is greater than or equal to the set value; a first relay that operates when outputs from the first and second temperature comparison circuits are simultaneously received; a second relay that operates when the heating medium temperature is higher than a high limit value; In a state in which the means selects the heating medium temperature signal, an air bleed alarm signal is issued when the first relay operates, and in a state in which the second switch means selects the hot water temperature signal, the first relay outputs the bleed alarm signal. an output circuit that issues an air bleed alarm signal when both the relay and the second relay operate;
position and a "freeze" position, and in the "operation" position, the control output from the calculation control section is supplied to the operation control relay of the reduced pressure steam type hot water generator,
In the "freeze" position, the control output is supplied to the operation control relay, and the heating medium temperature signal is supplied to the arithmetic control section, which causes the heating medium temperature signal to be compared with a fixed set value. 3. A temperature regulator for a reduced pressure steam type hot water generator, characterized in that it has a switch means of 3.