JP6686512B2 - Boiler system - Google Patents

Description

  The present invention relates to a boiler system. More specifically, the present invention relates to a closed-type boiler system that collects drainage discharged from a load device without releasing it to the atmosphere and supplies water to the boiler.

  Conventionally, steam generated by a boiler is supplied to load equipment, and the drain generated by condensation of the steam used as a heat source in the load equipment is collected in a sealed drain tank with pressure resistance at high temperature and high pressure. Then, a closed-type boiler system for supplying water to the boiler again has been proposed (for example, refer to Patent Document 1).

JP, 2013-205006, A

  By the way, in the closed type boiler system, the drain accommodated in the drain tank is preferentially supplied to the boiler, and when the amount of the supplied drain is insufficient, fresh water is supplied to the boiler. Therefore, if the amount of drain collected in the drain tank is small, or if the capacity of the drain tank is small, the drain supply to the boiler tends to be insufficient, and the drain supply from the drain tank to the boiler and the boiler supply The supply of fresh water to the plant frequently changes. If the switching of the water supply frequently occurs in this way, the boiler is overloaded due to repeated thermal stress.

  Therefore, an object of the present invention is to provide a boiler system capable of preventing an excessive load from being applied to a boiler due to frequent switching of water supply.

  The present invention relates to a boiler device that generates steam and supplies it to a load device, a drain tank that collects a drain generated by condensation of the load device by using steam without opening to the atmosphere, and the load device. And a drain recovery line that connects the drain tank, a drain supply line that supplies the drain accommodated in the drain tank to the boiler device, and a fresh water supply line that supplies fresh water to the boiler device. A boiler system, wherein the boiler device has a first water supply mode in which water is supplied from the drain supply line and / or the fresh water supply line, and a second water supply mode in which water is supplied only from the fresh water supply line, The present invention relates to a boiler system including a water supply mode changeover switch that switches between a first water supply mode and the second water supply mode.

  Further, the boiler system further includes a water level detection unit that detects the water level of the boiler, and a water supply control unit that controls water supply to the boiler device based on the water level of the boiler device detected by the water level detection unit. The water supply control unit includes a first control unit that starts supply of drain from the drain supply line to the boiler device when the boiler device is set to the first water supply mode, and the first water supply control unit. In the state where the supply of the drain from the drain supply line to the boiler device is started by the control unit, when the water level of the boiler device falls below a first threshold value, the drain from the drain supply line to the boiler device It is preferable that the second control unit stop the supply and start the supply of fresh water from the fresh water supply line to the boiler device.

  Further, the present invention, a boiler device for generating steam to supply to the load device, a drain tank for collecting the drain generated by the load device is condensed by using the steam without opening to the atmosphere, A drain recovery line that connects the load device and the drain tank, a drain supply line that supplies the drain accommodated in the drain tank to the boiler device, and a fresh water supply line that supplies fresh water to the boiler device, A boiler system comprising: a water level detection unit that detects the water level of the boiler device; and a water supply control unit that controls the water supply to the boiler device based on the water level of the boiler device detected by the water level detection unit. , The boiler device includes a first water supply mode in which water is supplied from the drain supply line and / or the fresh water supply line, and only from the fresh water supply line. A second water supply mode for receiving water, wherein the water supply control unit starts the supply of drain from the drain supply line to the boiler device when the boiler device is set to the first water supply mode. In a state in which the supply of drain from the drain supply line to the boiler apparatus is started by the first control section that causes the drain apparatus to start the drain apparatus when the water level of the boiler apparatus falls below a first threshold value. A second threshold value in which the supply of drain from the supply line to the boiler apparatus is stopped to start the supply of fresh water from the fresh water supply line to the boiler apparatus, and the water level of the boiler apparatus is higher than the first threshold value. And a second control unit for stopping the water supply from the fresh water supply line to the boiler device when the temperature exceeds the predetermined value, and the control by the second control unit is performed a predetermined number of times during a predetermined time. A water supply mode switching unit for switching the water supply mode to the first water supply mode from the second water supply mode if, relates boiler system comprising a.

  Further, it is preferable that the boiler device includes a plurality of once-through boilers.

  According to the boiler system of the present invention, it is possible to prevent an excessive load from being applied to the boiler due to frequent switching of water supply.

It is a figure which shows the structure of the boiler system which concerns on 1st Embodiment of this invention. It is a functional block diagram which shows the structure of the water supply control part of 1st Embodiment. It is a figure which shows the structure of the boiler system which concerns on 2nd Embodiment of this invention. It is a functional block diagram which shows the structure of the control apparatus of 2nd Embodiment. It is a figure which shows the structure of the boiler system which concerns on 3rd Embodiment of this invention.

  Hereinafter, preferred embodiments of the boiler system of the present invention will be described with reference to the drawings. First, the boiler system 1 of the first embodiment will be described with reference to FIGS. 1 and 2. The boiler system 1 of the first embodiment is a closed-type boiler system that collects drainage discharged from a load device without opening it to the atmosphere.

  The boiler system 1 of 1st Embodiment is equipped with the boiler apparatus 10, the drain tank 20, and the open tank 30, as shown in FIG. The boiler system 1 also includes a plurality of lines that connect these devices and through which steam or water flows. Specifically, the boiler system 1 includes, as lines, a steam supply line L1, a drain recovery line L2, a drain supply line L3, a flash steam line L4, and a fresh water supply line L5.

  As shown in FIG. 1, the boiler device 10 includes a plurality of once-through boilers 11, a steam header 12 in which steam generated by the once-through boilers 11 is collected, and a connection that connects the once-through boiler 11 and the steam header 12. And a tube 13.

The once-through boiler 11 heats the feed water supplied therein with combustion gas to generate steam. In the present embodiment, the once-through boiler 11 (a plurality of water pipes) is supplied with the drain collected in the drain tank 20 described later and the fresh water stored in the open tank 30 as the water supply.
In the first embodiment, the boiler device 10 includes three once-through boilers 11. Each of these three once-through boilers 11 has a water level sensor 111 as a water level detection unit, and a water supply control unit 112 that controls water supply to the once-through boiler 11 based on the water level of the once-through boiler 11 detected by the water level sensor 111. And a water supply mode switch 113 for switching the water supply mode of the once-through boiler 11. The details of the once-through boiler 11 will be described later.

As shown in FIG. 1, the steam generated in the once-through boiler 11 is supplied to the steam header 12 through the connecting pipe 13. The steam header 12 stores the steam generated in the once-through boiler 11 and supplies it to the load device 40.
The load device 40 uses the steam generated in the once-through boiler 11 as a heat source to exchange heat with the object to be heated.

The drain tank 20 is composed of a pressure vessel having pressure resistance. The drain tank 20 collects the drain generated by the steam generated by the once-through boiler 11 being condensed by being used in the load device 40 in a high temperature and high pressure state.
The drain tank 20 according to the first embodiment is a pressure vessel having a relatively small capacity of about 10 L to 40 L (for example, a small pressure vessel (pressure MPa × internal volume m ³ ≦ 0.02) according to the Industrial Safety and Health Act). Pressure vessels that are classified).

  The open tank 30 is open to the atmosphere. The open tank 30 stores fresh water (make-up water) supplied to the once-through boiler 11. In addition, the flash vapor generated from the drain in the drain tank 20 is introduced into the open tank 30 through a flash vapor line L4 described later.

The steam supply line L1 connects the steam header 12 and the load device 40, and supplies the steam generated in the boiler device 10 (the once-through boiler 11) to the load device 40.
The drain recovery line L2 connects the load device 40 and the drain tank 20, and supplies the drain generated in the load device 40 to the drain tank 20. A steam trap 21 and a check valve 22 are arranged in the drain recovery line L2.
The steam trap 21 is arranged downstream of the load device 40 in the drain recovery line L2, discharges the drain generated in the load device 40, and prevents the discharge of steam. The check valve 22 is arranged on the downstream side of the steam trap 21, and prevents the drain from flowing back to the load device 40 side in the drain recovery line L2.

  The drain supply line L3 delivers the drain accommodated in the drain tank 20. In the present embodiment, the drain supply line L3 connects the drain tank 20 and the once-through boiler 11, and supplies the drain collected in the drain tank 20 to the plurality of once-through boilers 11. The upstream end of the drain supply line L3 is connected to the lower portion of the drain tank 20. The downstream side of the drain supply line L3 is branched so as to be connected to each of the once-through boilers 11. A drain supply pump 31 and a drain supply valve 32 are arranged in the drain supply line L3.

The drain supply pump 31 is arranged on the upstream side of the branch portion of the drain supply line L3, and boosts the pressure of the drain supplied from the drain tank 20 and sends it to the once-through boiler 11 side. In the first embodiment, the output (operating frequency) of the drain supply pump 31 is preset based on the pressure of the drain collected in the drain tank 20 and the operating pressure of the once-through boiler 11.
The drain supply valve 32 is composed of a motor valve. The drain supply valve 32 is arranged downstream of the branch portion in the drain supply line L3, corresponding to each of the plurality of once-through boilers 11.

  The flash steam line L4 connects the drain tank 20 and the open tank 30, and discharges the flash steam generated in the drain tank 20 to the open tank 30. A pressure adjusting valve 41 is arranged in the flash steam line L4. When the pressure inside the drain tank 20 exceeds a predetermined pressure, the pressure regulating valve 41 allows flash vapor to escape to the open tank 30 side, and lowers the pressure inside the drain tank 20.

  The fresh water supply line L5 connects the open tank 30 and the plurality of once-through boilers 11. The fresh water supply line L5 supplies the water (fresh water) stored in the open tank 30 to the once-through boiler 11. In the first embodiment, the upstream end of the fresh water supply line L5 is connected to the lower part of the open tank 30. The downstream side of the fresh water supply line L5 is branched so as to be connected to each of the once-through boilers 11.

  A fresh water pump 51 is arranged in the fresh water supply line L5. The fresh water pump 51 boosts the fresh water supplied from the open tank 30 and supplies it to the once-through boiler 11. The fresh water pump 51 is arranged on the downstream side of the branch portion of the fresh water supply line L5, and a plurality of fresh water pumps 51 are provided corresponding to the plurality of once-through boilers 11.

In the boiler system 1 described above, the steam generated in the once-through boiler 11 is supplied from the steam header 12 to the load device 40 through the steam supply line L1 and is used as a heat source in the load device 40. The steam that has undergone heat exchange with the object to be heated in the load device 40 becomes a drain and is recovered in the drain tank 20 through the drain recovery line L2. The drain collected in the drain tank 20 is supplied from the drain supply line L3 to the boiler device 10 (the once-through boiler 11) in response to a water supply request of the boiler device 10 (the once-through boiler 11).
Further, when the water supply from the drain supply line L3 is insufficient, fresh water is supplied from the open tank 30 to the boiler device 10 (the once-through boiler 11) through the fresh water supply line L5.

Next, details of the operation of the once-through boiler 11 will be described.
The once-through boiler 11 of the first embodiment includes a first water supply mode and a second water supply mode as water supply modes. Then, these water supply modes are switched by the water supply mode changeover switch 113.
Further, the water supply control unit 112 performs different water supply control depending on the first water supply mode and the second water supply mode.

First, the first water supply mode will be described.
The first water supply mode is a mode in which water is supplied from the drain supply line L3 and / or the fresh water supply line L5. As a configuration for performing water supply control in the first water supply mode, the water supply control unit 112 includes a first control unit 114 and a second control unit 115, as shown in FIG.

The first control unit 114 starts the supply of drain from the drain supply line L3 to the boiler device 10 according to the water level of the once-through boiler 11 detected by the water level sensor 111. In the first embodiment, when the water level of the once-through boiler 11 detected by the water level sensor 111 is lower than the predetermined water supply start water level, the first control unit 114 opens the drain supply valve 32 and opens the drain supply line L3. The supply of drain to the boiler device 10 is started.
That is, when there is a water supply request, the first control unit 114 first preferentially supplies the drain from the drain supply line L3 to the boiler device 10. The water supply start water level is appropriately set according to the combustion state of the once-through boiler 11.
Further, the first control unit 114 closes the drain supply valve 32 to the boiler device 10 from the drain supply line L3 when the water level of the once-through boiler 11 detected by the water level sensor 111 exceeds a predetermined water supply stop water level. The drain supply is stopped.

  The 2nd control part 115 has the water level of the once-through boiler 11 below the preset 1st threshold value in the state where the supply of the drain to the once-through boiler 11 from the drain supply line L3 is started by the 1st control part 114. In this case, the drain supply valve 32 is closed to stop the supply of drain from the drain supply line L3 to the once-through boiler 11, and the fresh water pump 51 is driven to fresh water from the fresh water supply line L5 to the once-through boiler 11. To start feeding. In the first embodiment, the first threshold value is set to a value lower than the water supply start water level. Further, the second control unit 115 stops the driving of the fresh water pump 51 to supply fresh water when the water level of the once-through boiler 11 detected by the water level sensor 111 exceeds a second threshold value higher than the first threshold value. The supply of fresh water from the line L5 to the boiler device 10 is stopped. In the first embodiment, the second threshold value is set to the same value as the water supply stop water level.

  With the above water supply control, in the first water supply mode, when a water supply request is made, first, the drain is supplied from the drain supply line L3 preferentially, and the drain is not sufficiently supplied from the drain supply line L3. In this case, the supply of fresh water from the fresh water supply line L5 can be started. Thus, in the first water supply mode, the water supply can be appropriately switched according to the amount of drain supplied from the drain supply line L3, and the boiler system 1 can be stably operated while keeping the heat utilization efficiency of the boiler system 1 high. Be driven by.

Next, the second water supply mode will be described.
The second water supply mode is a mode in which water is supplied only from the fresh water supply line L5. In the second water supply mode, the water supply control unit 112 always closes the drain supply valve 32 to stop the supply of drain from the drain supply line L3, and the new water supply line L5 only supplies new water to the once-through boiler 11. Supply water. That is, in the second water supply mode, the water supply controller 112 controls the supply of fresh water from the fresh water supply line L5 to the boiler device 10 according to the water level of the once-through boiler 11 detected by the water level sensor 111. In the first embodiment, when the water level of the once-through boiler 11 detected by the water level sensor 111 is lower than the predetermined water supply start water level, the water supply control unit 112 drives the fresh water pump 51 to start the fresh water supply line L5. Supply of fresh water to the boiler device 10 is started. Further, when the water level of the once-through boiler 11 detected by the water level sensor 111 exceeds a predetermined water supply stop water level, the water supply control unit 112 stops the driving of the fresh water pump 51 and starts the fresh water supply line L5 from the boiler device. Stop the supply of fresh water to 10.

  The water supply mode changeover switch 113 is a physical switch for switching between the first water supply mode and the second water supply mode, and the water supply mode is changed over by operating the water supply mode changeover switch 113.

  In the first embodiment, the boiler device 10 (the once-through boiler 11) is configured to include the first water supply mode, the second water supply mode, and the water supply mode changeover switch, so that the water supply is frequently switched. This prevents the boiler from being overloaded.

That is, in the first water supply mode, the drain accommodated in the drain tank 20 is preferentially supplied to the boiler device 10, and when the amount of the supplied drain is insufficient, fresh water is supplied to the boiler device 10. To be done. Therefore, when the drain recovery amount to the drain tank 20 is small, or when the drain tank 20 has a small capacity, the supply of drain to the boiler device 10 is likely to be insufficient, and the drain tank 20 to the boiler device 10 tends to run short. Switching between the drain supply and the fresh water supply to the boiler device 10 frequently occurs.
When the switching of the water supply frequently occurs in this manner, an excessive load is applied to the device that constitutes the boiler device 10 (for example, an economizer that heats the water supply by the exhaust gas discharged from the once-through boiler 11) due to repeated thermal stress. In some cases, the life of the device was shortened.

  Therefore, in the boiler system 1, a first water supply mode in which water is supplied from the drain supply line L3 and / or the fresh water supply line L5, a second water supply mode in which water is supplied only from the fresh water supply line L5, and these first water supply modes The boiler device 10 (the once-through boiler 11) including the water supply mode switch 113 for switching between the water supply mode and the second water supply mode is configured. As a result, for example, in the state where water is being supplied in the first water supply mode, the amount of drain collected in the drain tank 20 is reduced, and the drain is supplied from the drain tank 20 to the boiler device 10 and to the boiler device 10. In the case where switching to fresh water supply is frequently repeated, the water supply mode can be switched to the second water supply mode by operating the water supply mode changeover switch 113. Therefore, it is possible to prevent frequent switching of the water supply by switching to the second water supply mode, and therefore, it is possible to repeatedly use the equipment that constitutes the boiler device 10 (for example, an economizer that heats the water supply by the exhaust gas discharged from the once-through boiler 11). Excessive load on the device due to such thermal stress can be suppressed, and the life of the device can be extended.

  Further, when the boiler device 10 is set to the first water supply mode, the water supply control unit 112 is configured to start the supply of drain from the drain supply line L3 to the boiler device 10, and the drain supply line. In a state where the supply of drain from L3 to the boiler device 10 is started, when the water level of the boiler device 10 falls below the first threshold value, the supply of fresh water from the fresh water supply line L5 to the boiler device 10 is started. The second control unit 115 is included. Accordingly, in the first water supply mode, when a water supply request is made, first, the drain is supplied from the drain supply line L3 preferentially, and when the drain is not sufficiently supplied from the drain supply line L3. , The supply of fresh water from the fresh water supply line L5 can be started. Thus, in the first water supply mode, the water supply can be appropriately switched according to the amount of drain supplied from the drain supply line L3, and the boiler system 1 can be stably operated while keeping the heat utilization efficiency of the boiler system 1 high. Be driven by.

  When the boiler device 10 is configured to include a plurality of once-through boilers 11, a part (for example, one) of the once-through boilers 11 among the once-through boilers 11 is operated in the second water supply mode. The drain can be preferentially supplied to the other once-through boilers 11. As a result, frequent switching of the water supply control of the once-through boiler 11 operating in the first water supply mode can be suppressed, so that the boiler system 1 can be operated more stably.

  Next, a boiler system 1A according to the second embodiment will be described with reference to FIGS. 3 and 4. The boiler system 1A of the second embodiment is different from the first embodiment mainly in that it includes a control device having a water supply control unit that switches between the first water supply mode and the second water supply mode. In the description of the second and subsequent embodiments, the same constituents will be given the same reference numeral, and the description thereof will be omitted or simplified.

Boiler system 1A of 2nd Embodiment is provided with the control apparatus 100 which controls operation | movement of 1 A of boiler systems in addition to the structure of 1st Embodiment. The control device 100 controls the operation of the boiler system 1A by controlling the operation of the boiler device 10 (the plurality of once-through boilers 11) and the operation of various valves and pumps.
The control device 100 is configured to include a water supply controller 120 that controls water supply to the once-through boiler 11 based on the water level of the once-through boiler 11 detected by the water level sensor 111. Switching control to the second water supply mode is performed.
As shown in FIG. 4, the water supply control unit 120 includes a first control unit 121, a second control unit 122, and a water supply mode switching unit 123.

  When the boiler device 10 (the once-through boiler 11) is set to the first water supply mode, the first control unit 121, when the water level of the once-through boiler 11 detected by the water level sensor 111 is below the water supply start water level, The drain supply valve 32 is opened to start the drain supply from the drain supply line L3 to the boiler device 10. In addition, when the water level of the once-through boiler 11 detected by the water level sensor 111 exceeds the water supply stop water level, the first control unit 121 closes the drain supply valve 32 and the drain from the drain supply line L3 to the boiler device 10. Stop the supply of.

  When the water level of the once-through boiler 11 falls below the first threshold value in a state where the supply of the drain from the drain supply line L3 to the once-through boiler 11 is started by the first controller 121, the second controller 122 causes the drain The supply valve 32 is closed and the supply of drain from the drain supply line L3 to the once-through boiler 11 is stopped, and the fresh water pump 51 is driven to start the supply of fresh water from the fresh water supply line L5 to the once-through boiler 11. Let Moreover, when the water level of the once-through boiler 11 detected by the water level sensor 111 exceeds the second threshold value, the second control unit 122 stops the driving of the fresh water pump 51 to start the fresh water supply line L5 to the boiler device 10. Stop the supply of fresh water to.

  The water supply mode switching unit 123 changes the water supply mode from the first water supply mode to the second water supply mode when the control by the second control unit 122 is performed a predetermined number of times (for example, twice) within a predetermined time (for example, 5 minutes). Switch to mode. Thereby, when the once-through boiler 11 is set to the first water supply mode and the water supply is switched at a predetermined frequency, the water supply mode can be switched to the second water supply mode. Therefore, it is possible to prevent frequent switching of water supply, and thus prevent an excessive load from being applied to the boiler.

According to the boiler system 1A of the second embodiment described above, in addition to the same effects as the first embodiment, the following effects are achieved.
A boiler device 10 including a boiler system 1A including a first water supply mode in which water is supplied from a drain supply line L3 and / or a fresh water supply line L5, and a second water supply mode in which water is supplied only from the fresh water supply line L5. The boiler apparatus 10 is configured to include a water supply controller 120 that controls water supply to the boiler apparatus 10 based on the water level of the boiler apparatus 10 (the once-through boiler 11), and the boiler apparatus 10 sets the water supply controller 120 in the first water supply mode. When set, the first control unit 121 that starts the supply of drain from the drain supply line L3 to the boiler device 10, and the supply of drain from the drain supply line L3 to the boiler device 10 by the first control unit 121. In the started state, when the water level of the boiler device 10 falls below the first threshold value, fresh water from the fresh water supply line L5 to the boiler device 10 is discharged. The second control unit 122 that starts the water supply and the water supply mode switching unit 123 that switches the water supply mode from the first water supply mode to the second water supply mode when the control by the second control unit 122 is performed a predetermined number of times within a predetermined time. It was composed including and. Accordingly, when the boiler device 10 is set to the first water supply mode and the water supply is switched at a predetermined frequency, the water supply mode can be switched to the second water supply mode. The thermal stress repeatedly applied to the equipment (for example, the economizer that heats the feed water by the exhaust gas discharged from the once-through boiler 11) constituting the boiler device 10 causes an excessive load on the equipment.

Next, a boiler system 1B according to the third embodiment will be described with reference to FIG. The boiler system 1B of 3rd Embodiment differs from 2nd Embodiment mainly in the point provided with the drain return line L6, and the structure of the drain tank 20B and the drain supply pump 31B.
The drain tank 20B is composed of a large-capacity pressure container having a capacity of about 100 L to 5000 L.

  The drain return line L6 connects the drain supply line L3 and the drain tank 20B. More specifically, the upstream (base end) end of the drain return line L6 is connected between the drain supply pump 31B and the drain supply valve 32 in the drain supply line L3. The downstream end of the drain return line L6 is connected to the side surface of the drain tank 20B. The drain return line L6 returns a part or all of the drain flowing through the drain supply line L3 to the drain tank 20B.

An orifice 61 and a pressure sensor 62 are arranged on the drain return line L6.
The orifice 61 adjusts the flow rate of the drain returned to the drain tank 20B.
The pressure sensor 62 is arranged upstream of the orifice 61 in the drain return line L6. The pressure sensor 62 detects the pressure of the drain flowing through the drain return line L6, that is, the discharge pressure of the drain from the drain supply pump 31B.

  The drain supply pump 31B includes a pump body 311B having an impeller and a motor that rotationally drives the impeller, and an inverter 312B that drives the motor. The drain supply pump 31B is driven at a rotation speed according to the frequency of the drive power supplied from the inverter 312B.

In the boiler system 1B of the third embodiment described above, the control device 100B performs the same water supply control as in the second embodiment, and the output of the drain supply pump 31B based on the drain pressure detected by the pressure sensor 62 ( The frequency output from the inverter 312B) is controlled.
That is, when the drain supply pump 31 is driven with a preset constant output, the discharge pressure of the drain supply pump 31 may become insufficient when the pressure of the drain collected in the drain tank 20 decreases. It was

  Therefore, in the third embodiment, the control device 100B controls the output of the drain supply pump 31B based on the pressure of the drain detected by the pressure sensor 62. More specifically, the control device 100 causes the inverter 312B to switch the pump body 311B from the inverter 312B so that the drain pressure detected by the pressure sensor 62 (the discharge pressure of the drain supply pump 31B) becomes a preset constant pressure. Controls the frequency of drive power supplied. As a result, even if the pressure of the drain collected in the drain tank 20B fluctuates, the discharge pressure of the drain from the drain supply pump 31B can be kept constant, so that the boiler system 1B can be operated more stably. Further, since the drain supply pump 31B can be operated at the optimum frequency, power saving of the boiler system 1B can be achieved.

Although the preferred embodiments of the boiler system according to the present invention have been described above, the present invention is not limited to the above-described embodiments and can be appropriately modified.
For example, in the first to third embodiments, the boiler systems 1, 1A, 1B are configured to include the boiler device 10 having the three once-through boilers 11, but the invention is not limited to this. That is, the boiler system may be configured to include a boiler device having one or two once-through boilers, or may be configured to include a boiler device having four or more once-through boilers.

  Further, in the first to third embodiments, the water supply control units 112 and 120 start water supply when the water level detected by the water level sensor 111 is lower than the water supply start water level, but the present invention is not limited to this. That is, the water level control unit may adjust the opening of the drain supply valve based on the water level detected by the water level sensor to continuously supply water to the once-through boiler.

  Further, in the first embodiment, the boiler system 1 is configured without including the control device, but the present invention is not limited to this. That is, the boiler system may be configured to include a control device, and this control device may control the water level of the boiler device.

1, 1A, 1B Boiler system 10 Boiler device 11 Through-flow boiler 20, 20B Drain tank 111 Water level sensor (water level detector)
112 Water Supply Control Section 113 Water Supply Mode Changeover Switch 114 First Control Section 115 Second Control Section 120 Water Supply Control Section 121 First Control Section 122 Second Control Section 123 Water Supply Mode Switching Section L2 Drain Recovery Line L3 Drain Supply Line L5 Fresh Water Supply line

Claims (4)

A boiler device that generates steam and supplies it to load equipment,
A drain tank for collecting the drain generated by condensing the load equipment by using steam without opening it to the atmosphere,
A drain recovery line connecting the load device and the drain tank,
A drain supply line for supplying the drain accommodated in the drain tank to the boiler device,
A fresh water supply line for supplying fresh water to the boiler device,
The boiler device is
A first water supply mode for receiving water from the drain supply line and / or the fresh water supply line;
A second water supply mode in which water is supplied only from the fresh water supply line,
A first water supply mode and a second water supply mode for switching the water supply mode changeover switch;
In the first water supply mode, the boiler device preferentially receives drain water supplied from the drain supply line, and a new water supply line is supplied from the new water supply line according to the amount of drain supplied from the drain supply line. To switch between water supply and
In the second water supply mode, the boiler device receives water only from the fresh water supply line in a state where the water supply of the drain from the drain supply line is always stopped.
The boiler system in which the boiler device switches between the first water supply mode and the second water supply mode by operating the water supply mode changeover switch . The boiler device is
A water level detection unit for detecting the water level of the boiler device,
Further comprising a water supply control unit for controlling the water supply to the boiler device based on the water level of the boiler device detected by the water level detection unit,
In the case where the boiler device is set to the first water supply mode, the water supply control unit,
A first controller for starting the supply of drain from the drain supply line to the boiler device;
In the state in which the drain supply from the drain supply line to the boiler device is started by the first control unit, when the water level of the boiler device falls below a first threshold value, the drain supply line to the boiler device is reached. 2. The boiler system according to claim 1, further comprising: a second control unit that stops the supply of the drain of the above and starts the supply of fresh water from the fresh water supply line to the boiler device. A boiler device that generates steam and supplies it to load equipment,
A drain tank for collecting the drain generated by condensing the load equipment by using steam without opening it to the atmosphere,
A drain recovery line connecting the load device and the drain tank,
A drain supply line for supplying the drain accommodated in the drain tank to the boiler device,
A fresh water supply line for supplying fresh water to the boiler device,
A water level detection unit for detecting the water level of the boiler device,
A water supply control unit for controlling water supply to the boiler device based on the water level of the boiler device detected by the water level detection unit, and a boiler system comprising:
The boiler device includes a first water supply mode in which water is supplied from the drain supply line and / or the new water supply line, and a second water supply mode in which water is supplied only from the new water supply line,
In the case where the boiler device is set to the first water supply mode, the water supply control unit,
A first controller for starting the supply of drain from the drain supply line to the boiler device;
In a state where the drain supply from the drain supply line to the boiler device is started by the first control unit, when the water level of the boiler device falls below a first threshold value, the drain supply line to the boiler device is reached. Of the drain of the boiler device to stop the supply of fresh water from the fresh water supply line to the boiler device, and when the water level of the boiler device exceeds a second threshold value higher than the first threshold value, A second controller for stopping water supply from the water supply line to the boiler device;
A water supply mode switching unit that switches the water supply mode from the first water supply mode to the second water supply mode when the control by the second control unit is performed a predetermined number of times during a predetermined time,
In the first water supply mode, the boiler device preferentially receives the water supply of the drain from the drain supply line, and a new water supply line from the new water supply line is supplied according to the amount of the drain supplied from the drain supply line. To switch between water supply and
In the second water supply mode, the boiler system receives water only from the fresh water supply line in a state where the water supply of the drain from the drain supply line is always stopped .   The boiler system according to claim 1, wherein the boiler device includes a plurality of once-through boilers.

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