KR19990038875A - Proportional Control Method of Gas Boiler Using Return Temperature - Google Patents

Abstract

The present invention relates to a proportional control method of a gas boiler, and more particularly, a combustion state of a boiler by measuring the temperature of the heating return water returned to the boiler after losing heat while passing through an indoor pipe and predicting the corresponding heating water temperature. It relates to a proportional control method of the gas boiler using a return temperature that can control the.

The proportional control method of the gas boiler using the return temperature of the present invention includes a microcomputer with a built-in program for controlling the entire stroke, a gas valve for controlling a gas output amount according to a control signal from the microcomputer, and a pipe through an indoor piping. A gas boiler comprising a heating return temperature sensor for measuring the temperature of the heating return to the boiler after releasing heat, and a room cone for inputting a command by the user, wherein the combustion stroke of the boiler is started in the early stage of combustion. The microcomputer outputs a control signal to the gas valve to perform the combustion stroke for a certain time with a certain amount of gas. A first step of performing a combustion stroke for a predetermined time; A second step of measuring a return temperature at a microcomputer using a heating return temperature sensor after a predetermined time has elapsed while the combustion administration is performed; Calculating a heating supply water temperature according to the measured heating return temperature; And a fourth step of performing proportional control on the basis of the calculated heating supply water temperature.

Description

Proportional Control Method of Gas Boiler Using Return Temperature

The present invention relates to a proportional control method of a gas boiler, and more particularly, a combustion state of a boiler by measuring the temperature of the heating return water returned to the boiler after losing heat while passing through an indoor pipe and predicting the corresponding heating water temperature. It relates to a proportional control method of the gas boiler using a return temperature that can control the.

Since gas boilers do not cause pollution due to their ease of use and low emission of environmental pollutants, they are increasingly being used for home and industry. Gas boilers are used to heat indoors or to supply hot water by using combustion heat generated when burning gas. 1 and 2 is a schematic view showing an embodiment of a conventionally used domestic gas boiler, the former is a configuration diagram of the boiler, the latter will be briefly described with reference to this as the electrical wiring diagram of the boiler.

As shown in FIG. 1, the gas boiler is a gas valve 1 for adjusting the amount of gas supplied through the gas supply pipe 2, and a gas boiler 1 for combusting the gas supplied from the gas valve 1. A burner 3 having an igniter 18 to generate and a salt voltage measuring device 17 for detecting a combustion state, and a heat exchanger for raising heating water and direct water by using heat generated by the burner 3 ( 4), the exhaust flue 5 for discharging the exhaust gas generated after burning in the burner 3, the flow switch 13 for detecting the movement state of the direct water flowing through the direct water supply pipe 10 and Hot water discharge pipe (11) for discharging hot water heated by the hot water heat exchanger (7) after flowing through the direct water supply pipe (10), and guided heating water discharged from the hot water heat exchanger (7) to the room Heating water supply pipe (9) and the heating water supply pipe (9) Directly through the water refilling water pipe (14) for returning the heating water discharged through the water, the bidirectional pump (8) for controlling the moving direction of the heating water, and the automatic refill water valve (15) to compensate for the insufficient heating water. It includes a water tank (6) to be supplied. Since the operating state of the block circuit diagram of FIG. 2 is the same as that described above, a detailed description thereof will be omitted.

When the gas valve 1 is opened, gas flows into the burner 3 along the gas supply pipe 2, and the burner 3 mixes and combusts gas and air at an appropriate ratio, and the combustion gas rises while the heat exchanger ( After heating 4), it is discharged through the exhaust flue 5.

In the conventional gas boiler having the above-described configuration, when the combustion stroke is performed at the burner 3 initially, the gas is rapidly supplied because the gas is supplied at the maximum allowable value of the gas valve 1 to reach the set temperature by the user. The temperature of the water rises but overheating has arisen.

In particular, when proportional control is performed using heating return, the heating water temperature rises rapidly because the burner is initially heated to maximum power, but the heating return returns after the heat is discharged as it passes through the room. The possibility of overheating existed depending on the heating load or piping conditions because the temperature difference of s widened more than the overheat range and the response speed was slow.

The present invention has been made to solve the above problems, an object of the present invention is to measure the temperature of the heating return to return to the boiler after the heat is deprived while passing through the indoor piping and predict the corresponding heating water temperature boiler It is to provide a proportional control method of a gas boiler using a return temperature that can control the combustion state of.

The proportional control method of the gas boiler using the return temperature of the present invention for achieving the above object is a microcomputer with a built-in program for controlling the entire stroke, a gas valve for controlling the gas output amount in accordance with the control signal from the microcomputer and In the gas boiler comprising a heating return temperature sensor for measuring the temperature of the heating return to return to the boiler after releasing heat while passing through the indoor piping, and a room cone for inputting a command by the user, the combustion stroke of the boiler At the beginning of combustion, the microcomputer outputs a control signal to the gas valve to perform the combustion stroke for a certain time with a certain amount of gas, and performs the combustion stroke for a certain time with a certain amount of gas increased after a certain time. The first step of performing the combustion stroke for a certain time with the increased constant gas volume again ; A second step of measuring a return temperature at a microcomputer using a heating return temperature sensor after a predetermined time has elapsed while the combustion administration is performed; Calculating a heating supply water temperature according to the measured heating return temperature; And a fourth step of performing proportional control based on the calculated heating supply water temperature.

1 is a schematic configuration diagram of a gas boiler conventionally used;

2 is a partial block circuit diagram of the gas boiler of FIG.

3 is a flowchart for explaining the method of the present invention,

4 is a graph showing a change in the gas supply amount used in the method of the present invention.

<Explanation of symbols for main parts of the drawings>

1: gas valve, 2: gas supply pipe,

3: burner, 4: heat exchanger,

5: exhaust year, 6: water tank,

7: hot water heat exchanger, 8: bidirectional pump,

9: heating water supply pipe, 10: direct water supply pipe,

11: hot water discharge pipe, 12: control unit,

13: flow switch, 14: heating return pipe,

15: automatic refill water valve, 16: replenishment water supply pipe,

17: salt voltage meter, 18: igniter,

19: heating return temperature sensor, 20: microcomputer,

Hereinafter, a proportional control method of a gas boiler using a return temperature of the present invention will be described in detail with reference to the accompanying drawings.

The method of the present invention is a method for performing proportional control by using a heating return temperature. When a combustion stroke is started, a combustion stroke is performed for a predetermined time with a gas consumption of a predetermined value and a temperature change of the heating return is detected accordingly. And it predicts the change of heating water according to the temperature change of heating return and uses it as the starting point and end point of proportional control.

The method of the present invention as described above, may be carried out using the conventional gas boiler circuit shown in Figure 2, the following steps: when the combustion stroke of the boiler starts the control signal to the gas valve in the microcomputer at the beginning of combustion Outputs the combustion stroke for a certain time with a certain amount of gas, and after a certain period of time performs a combustion stroke with a certain amount of gas increased after a certain time, and performs a combustion stroke for a certain time with a certain amount of gas increased again after a certain time. The first step to do; A second step of measuring a return temperature at a microcomputer using a heating return temperature sensor after a predetermined time has elapsed while the combustion administration is performed; Calculating a heating supply water temperature according to the measured heating return temperature; And a fourth step of performing proportional control based on the calculated heating supply water temperature.

When the boiler operation command is input from the user, the microcomputer 20 opens the gas valve 1 after performing the prepurge stroke and supplies gas to the burner 3. When ignition is achieved in the supplied gas, the microcomputer 20 does not supply gas with a maximizing force as in the prior art, but first burns the gas for a predetermined time T at a constant gas amount K. As the combustion stroke is performed in this way, the temperature of the heating water rises slowly rather than burning with the maximum force.

At this time, the constant gas amount K supplied to the burner 3 through the gas valve 1 is not always a fixed value, but may be changed such as 50% of the maximum force, 75% of the maximum force, and 100% of the maximum force. have. That is, after first burning at a constant time (T) at 50% of the maximum force (K1 state) and extinguishing, after a certain time (T), the second time at a constant time (T) at 75% of the maximum force (K2 state). And then extinguish after burning for a certain period of time (T) at 100% (K3 state) of the maximal force again after a certain time (T) and heating heating return temperature (Tr) so far. Measure using temperature sensor 19.

By measuring the heating return temperature in this way it is possible to predict the temperature change of the heating water supply to some extent. For example, if the temperature change rate (ΔT / t) is 1 ° C / min when the combustion stroke is performed in the state of K1, it may not reach the set temperature of the overheat protection device installed on the heating supply after a certain time. It can be roughly calculated. It can be seen that this can be especially applied when the controlled heating return temperature set by the consumer is relatively low.

Assuming that the heating water circulation flow rate (m) is 600 l / h in a boiler with a maximum heating power of 20,000 Kcal / h, the calorific value Q is At Q = mcΔt = m (Ts-Tr), Ts = Tr + (Q / m). Where c is 1 as the specific heat of water.

At this time, the temperature rise of the heating supply temperature (Ts), Q / mc = 16.67 ℃ / min, so if the set temperature of the overheat protection device is 80 ℃ and the heating return temperature (Tr) is 40 ℃, it will prevent overheating after about 23 minutes. It can be expected to reach the set temperature of the safety device. Therefore, if the heating return temperature (Tr) is 40 ℃ when burning in the state of K1 means more than 23 minutes combustion means that the operation of the overheat prevention safety device. If the user's set temperature is 70 ℃, the heating return temperature (Tr) is expected to reach the set temperature after 30 minutes, but it will be turned off after 23 minutes, so the proportional control should be started to lower the gas consumption before the calculated time. The starting point of the proportional control is determined by the designer according to the user's set temperature, and the gas consumption is calculated by the method described above according to the starting point.

The starting point of proportional control is set temperature-(3 ~ 5 ℃) when user set temperature is below 35 ℃, set temperature-(5 ~ 8 ℃) and user set temperature when user set temperature is 35 ~ 45 ℃ In the case of more than a degreeC, the set temperature-(8 to 10 ° C) is preferable.

After measuring the heating return temperature Tr as described above, the microcomputer 20 calculates the heating supply water temperature. In other words, when the heating return temperature is a, the heating supply water temperature at this time is A, and the temperature data is stored in advance. The microcomputer 20 estimates the heating water supply temperature using the stored data and calculates the temperature data accordingly.

By calculating the temperature data according to the heating return as described above, the microcomputer 20 determines whether the proportional control is to be performed at a certain temperature according to the designer's setting value with respect to the temperature set by the user, and calculates the gas consumption in this case. If the calculated gas consumption is smaller than the minimum consumption, it is determined as the minimum gas consumption to perform proportional control.

According to the present invention as described above by measuring the temperature of the heating return to return to the boiler after the heat is taken out while passing through the indoor piping and predicts the corresponding heating water temperature to control the combustion state of the boiler to the operation of the overheat safety device. It is possible to achieve rapid heating and comfortable heating by not extinguishing before reaching the user set temperature.

Although the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that modifications and variations can be made within the spirit and scope of the invention, and such variations or modifications will belong to the appended claims. .

Claims (2)

A microcomputer 20 incorporating a program for controlling the entire stroke, a gas valve 1 for controlling a gas output amount in accordance with a control signal from the microcomputer 20, and a boiler after discharging heat while passing through an indoor piping In the gas boiler comprising a heating return temperature sensor 19 for measuring the temperature of the heating return to return to, and a room cone 21 for inputting a command by the user, When the combustion stroke of the boiler starts, at the beginning of combustion, the microcomputer 20 outputs a control signal to the gas valve 1 to perform the combustion stroke for a predetermined time T with the constant gas amount K1, and then, after the predetermined time T, The combustion stroke is performed for a predetermined time T with the increased constant gas amount K2, and the combustion stroke is performed for a predetermined time T with the constant gas amount K3 increased again from the previous time after the predetermined time T. Stage 1; A second step of measuring a return temperature Tr at the microcomputer 20 using a heating return temperature sensor 19 after a predetermined time T has elapsed while the combustion stroke is performed; Calculating a heating supply water temperature (Ts) according to the measured heating return temperature (Tr); And a fourth step of performing a proportional control on the basis of the calculated heating supply water temperature (Ts). 2. The set point of claim 1, wherein the starting point of the proportional control is set temperature-(3 to 5 DEG C) when the user set temperature is 35 DEG C or lower, and set temperature-(5 to 8 DEG C) when the user set temperature is 35 to 45 DEG C. And, if the user set temperature is more than 45 ℃ set temperature-(8 ~ 10 ℃) characterized in that the proportional control method of the gas boiler using the return temperature.