JPH03279714A - Hot-water heating apparatus - Google Patents

Abstract

PURPOSE:To obtain an excellent hot-water production property regardless of the size of the load on the radiator by providing a soft start circuit which gradually increases a combustion volume at the start of heating. CONSTITUTION:When a signal to start heating is inputted into a controller 8, combustion commences with a combustion volume set at a minimum level. A hot-water temperature TM is compared with a set temperatures TS. If the hot-water temperature TM is low, a predetermined gas pressure is added at predetermined intervals. When the hot-water temperature T rises to the set temperature TS the predetermined gas pressure is subtracted at predetermined intervals. Whether or not the hot-water temperature TM will decrease is judged, and if it does, additions are, again, performed. If the hot-water temperature does not decrease, whether or not the gas pressure at that point is a predetermined value permitting a shift to proportional control action is judged. If not the predetermined value, subtractions continue. Once the predetermined value is reached, the shift is made to proportional control action. Hence, regardless of the degree of the load, the hot-water temperature reaches the set temperature in a smooth characteristic manner.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a hot water heating device.

(Prior Art) In a conventional hot water heating system, a heat exchanger and a radiator are connected by a circulation circuit, and hot water is circulated by a pump interposed in the circulation circuit. The hot water temperature is controlled by detecting the temperature at the outlet of the heat exchanger and proportionally controlling the proportional valve of the burner that heats the heat exchanger so that the salinity is constant.

(Problem to be Solved by the Invention) By the way, since the water temperature is low at the start of heating, the proportional valve opens to a large degree and burns at a large capacity to speed up the start-up as much as possible. However, when the load on the radiator is small, the temperature of the hot water returning to the heat exchanger does not drop very much, and as it is heated at high capacity, the temperature of the hot water rising too high, causing combustion. I ended up having to turn it off. When the combustion is turned off, the temperature of the hot water drops, so the combustion is turned on again. However, when the load is small, the flow rate is low and the delay until temperature detection is large, resulting in frequent overshoots and undershoots. Therefore, although the hot water rises quickly, the hot water output characteristics are poor and it takes time for the hot water humidity to stabilize. That is, on the radiator side, hot air comes out at first, then becomes cold, and this process is repeated until the air becomes appropriately hot, which causes discomfort.

It is an object of the present invention to eliminate the above-mentioned conventional drawbacks and provide a wet water heating system that provides good hot water output characteristics regardless of the magnitude of the load on the radiator, that is, reduces the number of times the combustion is turned on and off.

(Means for Solving the Problems) In order to achieve the above object, the present invention is characterized by the following configuration. That is, a soft start circuit is provided that gradually increases the amount of combustion when heating starts.

(Function) When heating starts, the amount of combustion starts from a small amount, so even if the load on the radiator is small, the water that has returned to the heat exchanger will not suddenly become hot. Therefore, the on/off of combustion is eliminated, and the hot water tapping characteristics are improved.

(Example) An embodiment of the present invention will be described based on the drawings.

1 is a heat exchanger, 2 is a radiator, and these are connected to a circulation circuit 3.
It is connected with 4 is a pump interposed in the circulation circuit 3. 5 is a burner that heats the heat exchanger 1, and the combustion amount is controlled by a proportional valve 6. A temperature detector 7 is provided at the outlet of the heat exchanger 1 and detects the hot water temperature. 8 is a controller which controls the proportional valve 6 in response to the signal from the temperature detector 7, and includes an adder circuit 9 which is a soft start circuit that gradually increases the combustion amount when heating starts, and an adder circuit 9 which is a soft start circuit that gradually increases the combustion amount when heating starts. A subtraction circuit 10 reduces the combustion amount if the set temperature is detected while increasing the combustion amount, and proportional control starts when the output temperature does not decrease while decreasing the combustion amount and reaches a predetermined value. It has a built-in proportional control circuit 11 that starts the process. These circuits are constructed by a microcomputer, the flow of which is shown in FIG.

Next, the operation of the above configuration will be explained.

When the heating operation start signal is input to the controller 8 (Sl),
The combustion amount (gas pressure) G is set to the minimum and combustion is started (S2). Next, compare the hot water outlet temperature T and the set temperature Ts (S3), and if the hot water outlet temperature T11 is low, the constant gas pressure (Δ
G) is added at regular intervals (S4). The hot water temperature T gradually rises, and when it reaches the set temperature Ts, the constant gas pressure (ΔG) is subtracted at regular intervals.
(S5). Then, it is determined whether the hot water temperature TII is decreasing or not (S6), and if it is decreasing, it is added again (S7). If the tapping temperature TN does not decrease, it is determined whether the gas pressure G at that point is at a certain predetermined value that allows transition to proportional control (S
8) If it is not a predetermined value, subtraction is continued (S5), and if it is a predetermined value, the process shifts to proportional control.

Therefore, as shown in FIG. 3, the tapped water temperature reaches the set temperature with smooth characteristics regardless of the magnitude of the load. That is, when the load is small, even if the initially heated water returns to the heat exchanger 1, the gas pressure at that time has not yet reached its maximum and will not significantly exceed the set temperature. Moreover, since the gas pressure is forcibly reduced when the set temperature is exceeded, the oversud amount can be further reduced.

Note that when the load is large, it takes longer for the outlet water temperature to reach the set temperature than in the conventional method, but there is no significant difference in the time it takes for the water temperature to stabilize, and there is no problem in actual use.

(Effects of the Invention) As described above, the present invention gradually increases the amount of combustion at the start of heating operation, so good hot water output characteristics can be obtained regardless of the load on the radiator, and the number of times combustion is turned on and off is achieved. As a result, the durability of gas valves, igniters, etc. is improved, and the usability is also improved.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the present invention, FIG. 2 is a control flowchart, and FIG. 3 is a time chart of gas pressure and tapping temperature. FIG. 4 is a conventional time chart of gas pressure and tapping temperature. 1...Heat exchanger 2...Radiator 3...Circulation circuit 4...Pump 5...Burner 6...Proportional valve 7...Temperature detector 8...Sterifier 9・ ・ ・Soft start circuit

Claims (1)

[Claims] A hot water heating system in which a heat exchanger and a radiator are connected by a circulation circuit and hot water is circulated by a pump interposed in the circulation circuit, which is equipped with a soft start circuit that gradually increases the amount of combustion when heating starts. A hot water heating device featuring: