JP7545183B2 - Boiler Equipment - Google Patents

Description

The present invention relates to a technology for controlling the outlet water temperature to a set temperature using multiple boilers.

Technology has been known for some time now that uses multiple boilers to control the heating of hot water to a set temperature. By using multiple boilers in this way, the capacity of each boiler can be reduced, which has the advantage of preventing a decrease in efficiency at low hot water output levels, for example, when a single boiler is configured to cover the entire range of hot water output levels.

An example of a technology related to multiple boilers is the technology for controlling the number of boilers installed in a multi-tube system described in Patent Document 1 below. The technology for controlling the number of boilers is briefly explained below with reference to Figure 4.

JP 11-337004 A

The number control technology involves installing multiple boilers, determining the number of boilers to be burned depending on the amount of steam required, and sequentially burning the required number of boilers according to their operating priority.

As shown in Figure 4, if an increase in the amount of steam required occurs while one boiler is burning, the number of boilers burning is increased according to the preset operation priority order. If the number of boilers in operation is subsequently reduced due to a decrease in the amount of steam required, the boiler operation priority order is changed and one of the boilers other than the one that had just started burning is stopped.

By controlling in this way, boilers that have just started combustion are stopped in a short time, preventing a particular boiler from frequently turning on and off repeatedly. In other words, the system is designed to stop boilers first, starting with those that have been in operation for the longest time.

By periodically changing the boiler operation priority as described above, the boiler combustion time can be averaged, which has the advantage of extending the lifespan of the entire system.

However, while the aforementioned method of controlling the number of boilers can extend the lifespan of the entire system, it also averages out the combustion time of multiple boilers, increasing the risk of multiple boilers failing at the same time. This results in high repair costs for the system at one time, creating management risks.

The present invention aims to provide a boiler system equipped with boiler number control technology that can extend the life of the entire system and minimize the risk of multiple boilers failing at the same time.

The invention described in claim 1 includes a boiler body for storing boiler water, a burner for heating the boiler water, a pump for circulating boiler water between the boiler body and a heat transfer medium flow pipe connected to the outside of the boiler body, a boiler water temperature measuring temperature sensor for measuring the boiler water temperature flowing in the heat transfer medium flow pipe, a heat exchanger attached midway through the heat transfer medium flow pipe, a water inlet pipe and a hot water outlet pipe connected via the heat exchanger, a hot water outlet pipe temperature measuring temperature sensor for measuring the water temperature in the hot water outlet pipe, and a heating power command to the burner and a heating power command to the burner and a heating power command to the burner. The system is configured with multiple boilers equipped with a controller that controls the start/stop of the pump, and the temperature of the hot water flowing through the hot water outlet pipe is controlled by the multiple boilers. One of the multiple boilers selectively functions as a master boiler, and the other boilers selectively function as slave boilers. When the master boiler controls the operation of itself and the slave boilers so that the temperature of the hot water flowing through the hot water outlet pipe is a set temperature, the system is characterized by monitoring the cumulative operating time of the slave boilers and giving priority to operating the slave boilers with the longest operating times.

The invention described in claim 2 is a boiler body for storing boiler water, a burner for heating the boiler water, a pump for circulating boiler water between the boiler body and a heat transfer medium flow pipe connected to the outside of the boiler body, a boiler water temperature measuring temperature sensor for measuring the boiler water temperature flowing in the heat transfer medium flow pipe, a heat exchanger attached to the middle of the heat transfer medium flow pipe, a water inlet pipe and a hot water outlet pipe connected via the heat exchanger, a hot water outlet pipe temperature measuring temperature sensor for measuring the water temperature in the hot water outlet pipe, and a controller for detecting measured temperature information from the boiler water temperature measuring temperature sensor and the hot water outlet pipe temperature measuring temperature sensor, and for controlling a heating command to the burner and start/stop of the pump. The system is configured to include a plurality of boilers each equipped with a master boiler and a controller, and the temperature of the hot water flowing through the hot water discharge pipe is controlled by the plurality of boilers, one of the plurality of boilers selectively functions as a master boiler and the other boilers selectively function as slave boilers, and when the master boiler controls the operation of itself and the slave boilers so that the temperature of the hot water flowing through the hot water discharge pipe becomes a set temperature, the system is characterized in that it monitors the accumulated operating time of the slave boilers, and gives priority to operating the slave boilers with the longest operating times and stops operating the slave boilers with the shortest operating times.

According to the invention described in claims 1 and 2, the start and stop sequence of multiple boilers is not preset, and the master boiler and slave boiler functions are selectively set for each boiler each time it is operated, thereby making it possible to extend the life of the entire system consisting of multiple boilers.

In addition, the master boiler controls the slave boilers so that those with longer operating hours are given priority, and those with shorter operating hours are given priority for shutting down, making it possible to make the combustion time of each boiler unequal and minimizing the risk of boilers breaking down at the same time.

FIG. 2 is a configuration diagram of a master boiler or each slave boiler constituting the boiler apparatus of the present invention. FIG. 2 is a diagram showing an electrical system configuration of the master boiler or each slave boiler. FIG. 2 is a diagram showing the connection configuration of the master boiler or each slave boiler. 1 is a table showing the combustion state of each conventional boiler.

Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 3. Fig. 1 shows the configuration of each boiler (master boiler or slave boiler) A that constitutes the boiler system of the present invention.

In FIG. 1, 1 is a water tank that stores water (boiler water) to be used as a heat transfer medium, and 2 is a supply pipe that supplies boiler water to the water tank 1. 3 is a supply solenoid valve that is provided on the supply pipe 2 and switches between water supply and water stop, and is automatically controlled to open and close by the water supply function described below, so that a constant amount of water is always stored in the water tank 1.

4 is a heat transfer medium flow pipe that communicates with the inside of the water storage tank 1 and circulates the boiler water inside the water storage tank 1 to the outside of the water storage tank 1, and 5 is a circulation pump that circulates the boiler water between the inside of the water storage tank 1 and the heat transfer medium flow pipe 4.

6 is a temperature sensor attached to the heat transfer medium flow pipe 4 for measuring the boiler water temperature, and 7 is a heat exchanger provided on the heat transfer medium flow pipe 4.

8 is a burner for heating the water in the water storage tank 1 from outside the water storage tank 1, and 9 is a fuel supply pipe for supplying fuel to the burner 8. 10 is a fuel control solenoid valve that is attached to the fuel supply pipe 9 and switches the supply of fuel to the burner 8 on and off.

11 is an air supply pipe for supplying the air required for combustion to the burner 8, and 12 is an air supply solenoid valve for switching the supply of air to the burner 8 on and off.

13 is the water inlet pipe with the heat exchanger 7 located midway, and 14 is the hot water outlet pipe connected to the water inlet pipe 13 via the heat exchanger 7. 15 is a temperature sensor attached to the hot water outlet pipe 14 for measuring the temperature of the hot water outlet pipe.

16 indicates a controller for controlling various control devices constituting boiler A, such as solenoid valves 3, 10, and 12 constituting boiler A, a water level sensor (not shown) that detects the water level in the water tank 1, burner 8, and circulation pump 5, based on command signals from the operation panel described below and temperature information from temperature sensors 6 and 15.

Reference numeral 17 denotes a remote control that outputs command signals to controller 16, and like the operation panel, is operated to control the various control devices that make up boiler A.

Figure 2 is an electrical system diagram that explains the electrical connection state of the controller 16 shown in Figure 1 and its peripheral devices. As shown in Figure 2, the controller 16 is roughly composed of a control power supply unit 19 that is connected to an external power supply 18, a control unit 20 that operates by receiving control power from the control power supply unit 19, and an operation panel 21 that outputs command signals to the control unit 20.

The operation panel 21 includes an operation section for the operator to input instruction information to be output to the control section 20, as well as various display sections and setting sections.

The control unit 20 is controlled and instructed not only by the operation panel 21 but also by the remote control 17. The remote control 17 is supplied with a separate external power source 22. The functions of the remote control 17 are generally similar to those of the operation panel 21 described above, but since the remote control 17 is connected to multiple boilers A (only two are shown in FIG. 2) as shown in FIG. 2, it is also provided with switches and the like that allow multiple boilers A to be operated with a single remote control.

When command signals and various setting signals are input from the operation panel 21 or remote control 17, or various sensor information such as temperature sensors 6 and 15 connected to sensor contacts 23 is input to the control unit 20, the control unit 20 executes various settings based on the input setting information and controls the control device 24 and other boilers A according to the input command signals. Examples of the control device 24 include the solenoid valves 3, 10, and 12 shown in FIG. 1, a water level sensor (not shown) that detects the water level in the water tank 1, the burner 8, and the circulation pump 5.

Next, the physical connection state of each boiler (master boiler, slave boiler) A in the boiler system of the present invention is shown in Figure 3. As shown in Figure 3, the boiler system of the present invention has multiple boilers A (four in Figure 3) with the configuration shown in Figure 1 connected in series.

In other words, as shown in FIG. 3, a boiler device A having the same configuration as the boiler A shown in FIG. 1 is arranged, with the water inlet pipe 13 connected to the hot water outlet pipe 14 shown in FIG. 1, and further, a boiler device A having the same configuration, with the water inlet pipe 13 connected to the hot water outlet pipe 14 of the boiler device A connected in this way, is further connected.

In this way, by connecting multiple boilers A in series, the outlet water temperature is controlled to the set temperature by the multiple boilers A. In addition, in the present invention, one of the multiple boilers A functions as a master boiler, and the others function as slave boilers.

Which boiler is to be the master boiler or slave boiler can be determined in various ways, but for example, the boiler that is turned on first functions as the master boiler. In other words, in this invention, the master boiler and slave boiler are not fixed, but are selectively set. When one boiler is selectively set as the master boiler, the other boilers are automatically set and function as slave boilers.

Next, the operation of the boiler system of the present invention will be described. First, each boiler A shown in FIG. 3 stores a certain amount of boiler water in the water tank 1 when the power is turned on in preparation for hot water demand. At this time, as described above, for example, the boiler A that is turned on first functions as the master boiler A1, and the others function as slave boilers A2 to A4.

The water level in the water tank 1 of each boiler A1 to A4 is monitored by a water level sensor (not shown), which automatically switches the make-up solenoid valve 3 on and off. When the boiler water level becomes higher than the reference water level, the make-up solenoid valve 3 is closed to stop the water, and when it becomes low, the make-up solenoid valve 3 is opened to supply water to the water tank 1 (water supply function). Note that this water supply function may also be equipped with a function that determines that there is a water supply valve abnormality if the water level is detected to be low for a certain period of time or more.

The boiler water in the water tank 1 of each boiler A1 to A4 is heated to a predetermined temperature in advance in preparation for hot water demand. Specifically, fuel is sent to the burner 8 through the fuel supply pipe 9 by opening the fuel control solenoid valve 10, and air for combustion is sent to the burner 8 by opening the air supply solenoid valve 12.

Then, the burner 8 is ignited and the boiler water in the water storage tank 1 is heated to a predetermined temperature by the combustion of the burner 8. Whether or not the boiler water temperature has reached the predetermined temperature is determined by driving the circulation pump 5 to circulate the boiler water through the heat transfer medium flow pipe 4, detecting the circulating boiler water temperature with the boiler water temperature sensor 6 attached to the heat transfer medium flow pipe 4, and transmitting the detection result to the control unit 20 of the controller 16, whereby the control unit 20 is able to grasp the temperature.

The above preparations are carried out before a demand for hot water occurs, and when a demand for hot water actually occurs, the master boiler A1 first heats the outlet hot water temperature to the set temperature. There are two ways to control the outlet hot water temperature: the outlet hot water temperature control function and the boiler water temperature control function.

The outlet hot water temperature control function controls the flow rate of the circulation pump 5 and adjusts the outlet hot water temperature to the set temperature. The outlet hot water temperature is measured by a temperature sensor 15 for measuring the outlet hot water pipe temperature, and output to the control unit 20 of the controller 16. The control unit 20 receives this information and further controls the flow rate of the circulation pump 5 to control the outlet hot water temperature to approach the set temperature. By repeating the above operations, the outlet hot water temperature is adjusted to the set temperature.

The boiler water temperature control function controls the heat of the burner 8 and adjusts the boiler water temperature circulating in the heat transfer medium flow pipe 4 to a temperature that is a certain temperature higher than the set temperature. The boiler water temperature circulating in the heat transfer medium flow pipe 4 is detected by a temperature sensor 6 for measuring boiler water temperature, and measurement temperature information is output to the control unit 20 of the controller 16. The control unit 20, which receives this information, further controls the heat of the burner 8 so that the outlet water temperature approaches the set temperature. By repeating the above operations, the boiler water temperature is adjusted to the set temperature.

By executing the above-mentioned hot water outlet temperature control, the inlet water in the water inlet pipe 13 shown in FIG. 1 is heated to the set temperature by the heat exchanger 7 and is discharged from the hot water outlet pipe 14. In this way, the hot water outlet heated to the set temperature meets the hot water demand of the user.

Next, we will explain the operation when the demand for hot water increases while the above operations are being performed. When the demand for hot water increases, the boiler device of the present invention first heats the outlet hot water temperature to a set temperature that meets the demand for hot water using the master boiler A1 alone.

If the master boiler A1 alone is able to heat the outlet water temperature to the set temperature, the slave boilers A2 to A4 will not operate. This will increase the operating time of the master boiler A1 alone, but as mentioned above, in this invention, the master boiler is selected from multiple boilers each time it is operated, so the operating time of the master boiler A1 is averaged among the boilers the more operations are repeated, preventing early failure of a specific boiler alone.

In addition, if the heating power command for master boiler A1 reaches its upper limit but the outlet water temperature still does not reach the set temperature, the slave boilers A2 to A4, which were in a stopped state, will start operating.

The master boiler A1 has a function in the control unit 20 that monitors the cumulative operating time of the slave boilers A2 to A4, and the master boiler A1 operates the slave boilers A2 to A4 in order of the one with the longest cumulative operating time.

In other words, if the heating power command for master boiler A1 reaches the upper limit but the outlet hot water temperature does not reach the set temperature, master boiler A1 will start and operate the slave boiler A2 to A4 that has the longest cumulative operating time, for example, slave boiler A3.

If the outlet water temperature can be heated to the set temperature only by the master boiler A1 and slave boiler A3, the other slave boilers A2 and A4 will remain stopped.

On the other hand, if the heating power commands for both master boiler A1 and slave boiler A3 reach their upper limit but the outlet water temperature still does not reach the set temperature, the slave boiler A2 or A4 that was in a stopped state, for example slave boiler A4, which has the longest cumulative operating time, will start operating.

If the master boilers A1, A3, and A4 are able to heat the outlet water temperature to the set temperature, the slave boiler A2 will remain stopped.

On the other hand, if the heating power command for master boiler A1 and slave boilers A3 and A4 reaches the upper limit but the outlet hot water temperature does not reach the set temperature, operation of slave boiler A2, which is in a stopped state, is started to heat the outlet hot water temperature to the set temperature.

In this way, the boiler system of the present invention starts operation of the multiple boilers A in order, starting with the master boiler and the slave boiler with the longest operating time, making it possible to make the operating times of each boiler unequal and minimizing the risk of multiple boilers failing at the same time.

Next, we will explain how to control the operation of each boiler after the outlet water temperature reaches the set temperature or when the set temperature is lowered.

After the outlet water temperature reaches the set temperature or when the set temperature is lowered, the master boiler A1 stops operation of the slave boiler A2 to A4 that is in operation and has the shortest cumulative operating time, for example, slave boiler A2.

As a result, the boilers in operation are master boiler A1 and slave boilers A3 and A4, but if this state allows the outlet water temperature to be maintained at the set temperature, this operating state will continue.

On the other hand, if the outlet water temperature exceeds the set temperature even when the master boiler A1 and slave boilers A3 and A4 are operating, the master boiler A1 will stop operation of the slave boiler A3 or A4 that is in operation and has the shortest cumulative operating time, for example, slave boiler A4.

As a result, the boilers in operation become master boiler A1 and slave boiler A3, but if this state allows the outlet water temperature to be maintained at the set temperature, this operating state will continue.

On the other hand, if the outlet hot water temperature exceeds the set temperature even when the master boiler A1 and slave boiler A3 are operating, the master boiler A1 stops the operation of the slave boiler A3, which is in operation, and the outlet hot water temperature is maintained at the set temperature by the master boiler A1 alone.

In this way, the slave boilers A2 to A4 are shut down in order starting with the boiler with the shortest operating time, which makes it possible to make the operating time of each boiler unequal and minimizes the risk of multiple boilers failing at the same time.

The control of stopping each boiler is not limited to the case where the boilers are started in order of the longest operating time. For example, if the heating power command for master boiler A1 reaches its upper limit but the outlet hot water temperature still does not reach the set temperature, the stopped slave boilers A2 to A4 can be operated simultaneously to instantly heat the outlet hot water temperature to the set temperature, and then it is necessary to reduce the number of operating slave boilers A2 to A4.

In addition, in this embodiment, an example in which the number of slave boilers is three has been described, but it goes without saying that the scope of the present invention is not limited to this number.

The methods for setting each boiler include: (1) always fixing the boiler that will be the master boiler and averaging the operation time of the slave boilers so that there is no bias; (2) always fixing the boiler that will be the master boiler and operating the slave boilers by giving priority to the boiler with the longest operating time (inclined operation); (3) selectively setting the master boiler and averaging the operation of the other boilers that have become slave boilers; and (4) as in the present invention, selectively setting the master boiler and operating the other boilers that have become slave boilers in an inclined manner.

Comparing the above operating methods (1) to (4), method (1) can extend the life of the slave boiler, but it also causes the master boiler to break down early and the slave boilers to break down at the same time, which means that the object of the present invention cannot be achieved.

Method (2) fails to achieve the objective of the present invention because the master boiler and slave boiler will fail early and at the same time.

While method (3) can maximize the lifespan of each boiler, it also means that each boiler will fail at the same time, which does not achieve the objective of the present invention.

In contrast, according to the method (4) of the present invention, the lifespan of the boiler that fails first among the boilers in (4) can be made longer than the lifespan of the master boiler in the method (2), and the failure times of the other boilers do not overlap, so the object of the present invention can be achieved.

As described above, according to the boiler system of the present invention, a master boiler and a slave boiler are selectively set among multiple boilers, and when it is necessary to increase the number of boilers in operation, such as when the master boiler alone cannot heat the outlet water temperature to the set temperature, operation is started in order starting with the boiler with the longest operating time. Also, when it is necessary to reduce the number of operating slave boilers, such as when the outlet water temperature reaches the set temperature or drops below the set temperature, control is performed to stop operation in order starting with the boiler with the shortest operating time, making it possible to both extend the life of multiple boilers and avoid the risk of them breaking down at the same time.

It can be applied to boiler systems consisting of multiple boilers.

LIST OF SYMBOLS 1 Water storage tank 2 Supply pipe 3 Supply solenoid valve 4 Heat medium flow pipe 5 Circulation pump 6 Temperature sensor for measuring pipe water temperature 7 Heat exchanger 8 Burner 9 Fuel supply pipe 10 Fuel control solenoid valve 11 Air supply pipe 12 Air supply solenoid valve 13 Water inlet pipe 14 Hot water outlet pipe 15 Temperature sensor for measuring hot water outlet pipe temperature 16 Controller 17 Remote control 18, 22 External power supply 19 Control power supply unit 20 Control unit 21 Operation panel 23 Sensor contact 24 Control device A Boiler (master boiler A1, slave boilers A2 to A4)

Claims (2)

A boiler body that stores boiler water, a burner that heats the boiler water, a pump that circulates boiler water between the boiler body and a heat transfer medium flow pipe connected to the outside of the boiler body, a boiler water temperature measuring temperature sensor that measures the boiler water temperature flowing through the heat transfer medium flow pipe, a heat exchanger that is attached midway through the heat transfer medium flow pipe, a water inlet pipe and a hot water outlet pipe that are connected via the heat exchanger, a hot water outlet pipe temperature measuring temperature sensor that measures the water temperature in the hot water outlet pipe, and a heating command to the burner and a drive of the pump that detects measured temperature information from the boiler water temperature measuring temperature sensor and the hot water outlet pipe temperature measuring temperature sensor. A boiler system comprising a plurality of boilers each equipped with a controller for controlling the operation/stop of the boilers, and configured to control the temperature of the hot water flowing through the hot water outlet pipe by the plurality of boilers, one of the plurality of boilers selectively functions as a master boiler, and the other boilers selectively function as slave boilers, and when the master boiler controls the operation of itself and the slave boilers so that the temperature of the hot water flowing through the hot water outlet pipe is a set temperature, the boiler system is characterized in that it monitors the cumulative operating time of the slave boilers and operates the slave boilers with the longest operating time first. 2. The boiler apparatus according to claim 1 , wherein when the master boiler controls the operation of itself and the slave boilers, the master boiler monitors the accumulated operating time of the slave boilers and stops the operation of the slave boilers with the least operating time first .