JP7597585B2 - 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 that uses multiple boilers to heat and control hot water to a set temperature. By using multiple boilers, the capacity of each boiler can be reduced, which has the advantage of preventing a decrease in efficiency when the hot water output is low, compared to a configuration in which a single boiler covers the entire range of hot water output, for example.

An example of a technology for controlling multiple boilers is the automatic number control method described in Patent Document 1 below. This control method is briefly described below.

Japanese Patent Application Publication No. 3-11261

As shown in FIG. 4, the hot water boilers 101 described in Patent Document 1 are installed in parallel in multiple units, and the multiple boiler units 101 are connected to a load 102 such as a hot water supply facility by a hot water supply line 103 and a return line 104, and a flow rate sensor 108 is attached to the hot water supply line.

The load, such as a hot water supply system, is equipped with a heat exchanger 105 that transfers the heat of the hot water flowing from the multiple boilers 101 through the hot water supply system 103 and the return system 104 to the load 102, such as a hot water supply system, and a circulation pump 106 that circulates the hot water back to the boiler 101 through the hot water supply system 103, the upper header 111 as a hot water supply side collection point from the multiple boilers 101, the heat exchanger 105, the lower header 112 as a hot water return side collection point, and the return system 104.

In addition, the upper header 111 and lower header 112 of the load 102 are provided with a temperature sensor 107 that detects the temperature of the hot water collected therein, and a temperature sensor 110 that detects the temperature of the circulating water (hot water) of the load 102.

Note that 109 indicates an automatic number controller that controls the number of hot water boilers 101.

The heat source hot water, which has been heated by multiple hot water boilers 101 to a specified temperature, is circulated through the circulation system consisting of the hot water supply system 103, heat exchanger 105, and return system 104 by the operation of the circulation pump 106, and heat is exchanged in the heat exchangers 105 provided individually for the loads 102, supplying heat to each load.

The temperature sensor 107 detects the temperature of the hot water collected in the upper header 111 and the lower header 112, and the automatic number controller 109 controls the number of hot water boilers 101 in operation according to the temperature difference between the two.

When controlling the number of hot water boilers 101, the priority order for starting and stopping is determined in advance, and the hot water boilers 101 are started and stopped according to that priority. In addition, the priority order is rotated as appropriate to average the operating rate of each hot water boiler 101.

In addition, the flow rate sensor 108 detects the amount of circulating hot water from the heat source, and calculates the required amount of heat based on this amount of circulation and the temperature difference between the water temperature in the upper header 111 and the water temperature in the lower header 112.The number of hot water boilers 101 in operation is controlled according to this value.

When varying the amount of circulation of the heat source hot water, the temperature of the outlet hot water is detected by a temperature sensor 110 and the operation of the circulation pump 106 is controlled. If the load decreases and the amount of heat required decreases, the number of hot water boilers 101 in operation is reduced, and if the load increases and the amount of heat required increases, the number of hot water boilers 101 in operation is controlled to be increased.

As described above, the hot water boiler has the functions of controlling the number of hot water boilers 101 to be operated according to the magnitude of the temperature difference detected by two temperature sensors installed in the circulation path of the heat source hot water, calculating the required heat quantity according to the detection results of the flow rate sensor 108 and two temperature sensors installed in the circulation path of the heat source hot water and controlling the number of hot water boilers 101 to be operated according to this value, and detecting the outlet hot water temperature with a temperature sensor 110 and controlling the operation of the circulation pump 106 to vary the circulation amount of the heat source hot water. Such number control is performed by an automatic number controller 109 in a higher-level system of the hot water boiler 101.

Therefore, an automatic number controller 109 is required in addition to the multiple boilers 101. Also, a flow sensor 108 is required to calculate the required amount of heat. Flow sensors are relatively expensive, so the cost is high.

In addition, the need for an automatic unit count controller 109 complicates the system configuration.

The present invention aims to provide a boiler system that does not include an automatic unit count controller or a flow rate sensor that are installed separately from the hot water boiler.

The invention described in claim 1 provides a boiler having a plurality of boilers, the boiler having 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 controlling a heating command to the burner and drive/stop of the pump, and the hot water outlet flowing in the hot water outlet pipe is circulated by the plurality of boilers. In this configuration, one of the boilers functions as a master boiler and the others function as slave boilers, and the master boiler controls itself and the slave boilers so that the temperature of the hot water flowing through the hot water outlet pipe becomes the set temperature. This control combines a hot water outlet temperature control that controls the flow rate of a boiler water circulating pump and a boiler water temperature control that controls the heat of a burner and adjusts the boiler water temperature to a certain temperature higher than the set temperature , and is characterized in that the master boiler alone heats the hot water outlet temperature to the set temperature, and if the master boiler alone cannot heat the hot water outlet temperature to the set temperature, all of the slave boilers are operated simultaneously to heat the hot water outlet temperature to the set temperature .

The invention described in claim 2 is characterized in that the outlet hot water temperature control described in claim 1 is PI control.

The invention described in claim 3 is characterized in that the boiler water temperature control described in either claim 1 or claim 2 is PI control.

According to the invention described in claim 1, there is no need to provide a higher-level control device to control the boiler, and the device configuration can be simplified. In addition, there is no need for an expensive flow sensor, so the product cost can be reduced. In addition, the outlet water temperature can be heated to the set temperature in an extremely short time.

According to the invention described in claim 2, the outlet water temperature can be set to the set temperature by controlling the flow rate and the burner power.

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 the 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. FIG. 1 is a configuration diagram of a conventional hot water boiler.

The following describes an embodiment of the present invention with reference to Figures 1 to 3. Figure 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 attached to the fuel supply pipe 9 that 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 by the multiple boilers A to be the set temperature. In addition, in the present invention, one of the multiple boilers A is designated as the master boiler, and the others function as slave boilers. The master boiler controls the operation/stop of the slave boilers.

Which boiler is the master boiler or slave boiler can be determined in various ways, but for example, the boiler that is turned on first can function as the master boiler. In this way, when one boiler is 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). The 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 does arise, 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 as measured temperature information 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 control method varies depending on the configuration of the control equipment. For example, if an inverter that drives the circulation pump 5 is provided, the input signal is the temperature information measured by the temperature sensor 15 for measuring the hot water outlet pipe temperature, and the output signal is the inverter frequency setting signal, forming a PI control.

In addition, if such an inverter is not provided, the input signal is the temperature information measured by the temperature sensor 15 for measuring the hot water outlet pipe temperature, and the output signal is the on/off signal of the switch (not shown) of the circulation pump 5.

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 the measured 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.

The control method varies depending on the fuel. For example, in the case of gas firing, the input signal is the measured temperature information from the temperature sensor 6 for measuring the boiler water temperature, and the output signal is a PI control signal that sets the opening degree (closed to fully open) of the fuel control solenoid valve 10.

In the case of oil firing, the input signal is the temperature information measured by the temperature sensor 15 for measuring the temperature of the hot water outlet pipe, and the output signal is the on/off signal of the fuel control solenoid valve 10 (e.g., a three-position on/off signal).

At this time, the fuel control solenoid valve 10 and the air intake solenoid valve 12 are linked to keep the air-fuel ratio constant.

Next, an example of the operation when the demand for hot water increases while the above operations are being performed will be described. 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 hot water outlet temperature to the set temperature, the slave boilers A2 to A4 will not operate. However, if the hot water outlet temperature is still below the set temperature even after the heating power command for the master boiler A1 has reached its upper limit, the present invention simultaneously operates the slave boilers A2 to A4 that were stopped, as shown in Figure 4, to instantly heat the hot water outlet temperature to the set temperature.

After the hot water outlet temperature reaches the set temperature, the number of slave boilers A2 to A4 in operation is controlled to reduce the number of slave boilers A2 to A4 in operation, so that the hot water outlet temperature is maintained at the set temperature.

At this time, the outlet hot water temperature control of each boiler A1 to A4 is performed by the outlet hot water temperature control function and boiler water temperature control function described above. Unlike conventional technology, outlet hot water temperature control using this function does not require a flow sensor and can heat the outlet hot water temperature to a set temperature in response to an increase in hot water demand, reducing equipment costs.

In addition, the present invention can heat the outlet water temperature to the set temperature in an extremely short time compared to a method in which the slave boilers A2 to A4 are started in sequence after the heating power command for the master boiler A1 reaches its upper limit, thereby increasing the number of boilers (heat source devices) in operation.

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. The hot water outlet heated to the set temperature in this way meets the hot water demand of the user.

As described above, the boiler apparatus of the present invention is configured to control the flow rate of the boiler water circulation pump based on the temperature information measured by the temperature sensor for measuring the outlet hot water pipe temperature, even when the demand for hot water increases, so there is no need for an expensive flow rate sensor.

In addition, by having one of the multiple boilers function as a master boiler, the other slave boilers can be controlled by that master boiler, eliminating the need to provide a separate control device for controlling the multiple boilers and simplifying the system configuration.

In the above explanation, an example was given in which there are three slave boilers, but it goes without saying that the scope of the present invention is not limited to this number.

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 (3)

The boiler 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 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 the start/stop of the pump, and the temperature of the hot water flowing in the hot water outlet pipe is controlled by the plurality of boilers. one of the plurality of boilers functions as a master boiler and the others function as slave boilers, and the master boiler controls itself and the slave boilers so that the temperature of the hot water flowing through the hot water outlet pipe becomes a set temperature, and the control combines a hot water outlet temperature control that controls the flow rate of a boiler water circulating pump and a boiler water temperature control that controls the heat of a burner and adjusts the boiler water temperature to a certain temperature higher than the set temperature, and the master boiler alone heats the hot water to the set temperature, and if the master boiler alone cannot heat the hot water to the set temperature, all of the slave boilers are operated simultaneously to heat the hot water to the set temperature . The boiler device according to claim 1, characterized in that the outlet hot water temperature control is PI control when an inverter for driving a circulation pump is included as a component. The boiler apparatus according to claim 1 or 2, characterized in that the boiler water temperature control is a PI control when the supplied fuel is gas-fired, and a three-position on/off control of high output, low output, and off when the supplied fuel is oil-fired.