JP2014013117A - Boiler water supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure drain recovery and water supply to boilers by a simple configuration and prevent temperature unevenness in a water supply tank.SOLUTION: A water supply tank 3 stores water to be supplied to boilers 2. The water in the water supply tank 3 is supplied to a mixing box 4 through a circuit 5 in a circulating manner. The water from the circuit 5 is sprinkled in the mixing box 4, and a drain is opened in the sprinkled water. A bypass passage 6 for returning the water from a circulation pump 13 to the water supply tank 3 is divergingly located midway of the circuit 5. A three-way valve 14 is installed at a diverging portion between the circuit 5 and the bypass passage 6. A boiler water supply passage 7 is arranged so as to diverge downstream of the circulation pump 13 and upstream of the diverging portion from the bypass passage 6 in the circuit 5. When water is supplied to the boilers 2, the circulation pump 13 functions as a booster pump.

Description

  The present invention relates to a boiler water supply system that can collect drain from a steam using facility and supply water to a boiler.

  Conventionally, as disclosed in Patent Document 1 below, a drain recovery device (4) is provided in a water supply tank (2) of a boiler (1) to recover drain from the steam use facility (25) and its flash steam. It has been known.

  However, when drain and its flash steam are collected in the water supply tank, the water stored in the water supply tank becomes too hot, and there is a risk of causing cavitation in the water supply pump of the boiler.

  On the other hand, as a measure for preventing cavitation, it is also known to install a booster pump (11) upstream of the feed water pump (12) of the boiler (13), as disclosed in Patent Document 2 below.

JP 2009-150603 A Japanese Patent Laid-Open No. 2004-77050

  In the invention described in Patent Document 1, the drain recovery device (4) requires the circulation pump (20), whereas in the invention described in Patent Document 2, the booster pump (11) is required.

  Further, in the invention described in Patent Document 1, the water in the water supply tank (2) circulates only between the drain recovery device (4) and the circulation is not always performed ([0028] ), Temperature unevenness occurs in the stored water in the water supply tank (2). Similarly, in the invention described in Patent Document 2, the water in the water supply tank (10) circulates only between the suction stirring device (17) and the circulation is not always performed ([0022 ]), It is impossible to completely prevent uneven temperature of the stored water in the water supply tank (10). Furthermore, in the case of the invention described in Patent Document 2, the water supply flow rate to the suction agitator (17) varies depending on the presence or amount of water supply request in the boiler (13), which may affect the drain recovery. .

  Therefore, the problem to be solved by the present invention is to provide a boiler water supply system that can reliably perform drain recovery and water supply to the boiler with a simple configuration and can prevent temperature unevenness in the water supply tank. .

  The present invention has been made to solve the above problems, and the invention according to claim 1 is a water supply tank in which water supplied to a boiler is stored, and water in the water supply tank circulates through a circulation path. The water is supplied and sprinkled, and the drain from the steam using facility is released under the sprinkling, so that the flushing steam of the drain is condensed and recovered, and the circulation path is branched from the downstream from the circulation pump. A bypass path for returning water from the circulation pump to the water supply tank without passing through the mixing box, and supplying water from the circulation pump to the mixing box or the water supply via the bypass path A distribution amount adjusting means for adjusting a distribution ratio to be returned to the tank; and a branching unit that is downstream from the circulation pump and upstream from the branching unit with the bypass path in the circulation path. That is a boiler water supply system, characterized in that it comprises a boiler water supply path.

  According to the first aspect of the present invention, since the water supply path to the boiler is branched from the circulation path to the mixing box, the circulation pump also functions as a booster pump when the boiler water supply is requested. Therefore, it is not necessary to install a booster pump separately from the circulation pump. In addition, a bypass path is branched in the circulation path to the mixing box, and the distribution ratio of whether the water from the circulation pump is supplied to the mixing box or returned to the water supply tank via the bypass path is adjusted. The amount of water supplied to the box can be kept appropriate. Furthermore, since the stored water in the water supply tank is circulated between the mixing box and the bypass passage, temperature unevenness is reliably prevented.

  According to a second aspect of the present invention, the distribution amount adjusting means includes a three-way valve provided at a branch portion between the circulation path and the bypass path, and the three-way valve is connected to the boiler via the boiler water supply path. 2. The return amount to the water supply tank via the bypass path is adjusted so that the water supply amount to the mixing box is maintained at a predetermined value regardless of the presence or amount of water supply. It is a boiler water supply system of description.

  According to the invention described in claim 2, by adjusting the return amount to the water supply tank via the bypass passage, regardless of the presence or amount of water supplied to the boiler via the boiler water supply passage, The amount of water supply can be kept appropriate. In addition, the control can be easily performed with a three-way valve provided at a branch portion between the circulation path and the bypass path.

  Further, in the invention according to claim 3, when the water temperature in the water supply tank exceeds the upper limit temperature, the distribution amount adjusting means supplies the entire amount of water from the circulation pump to the water supply tank via the bypass passage. It returns, It is a boiler water supply system of Claim 1 or Claim 2 characterized by the above-mentioned.

  According to the third aspect of the present invention, when the water temperature in the water supply tank exceeds the upper limit temperature, the entire amount of water from the circulation pump is returned to the water supply tank via the bypass path, so that the heat from the drain is temporarily stored. Recovery can be suppressed and cavitation of each pump can be prevented.

  According to the boiler water supply system of the present invention, drain recovery and water supply to the boiler can be reliably performed with a simple configuration, and temperature unevenness in the water supply tank can be prevented.

It is the schematic which shows the use condition of one Example of the boiler water supply system of this invention. It is a figure which shows the modification of FIG. 1, and one part is abbreviate | omitted and shown.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a use state of an embodiment of a boiler water supply system 1 of the present invention. The boiler water supply system 1 is a system that can collect drainage from the steam using facility in the water supply tank 3 of the boiler 2 and can appropriately supply water in the water supply tank 3 to the boiler 2.

  The boiler water supply system 1 according to the present embodiment includes a water supply tank 3 for storing water supplied to the boiler 2, a mixing box 4 for collecting drain in the water supply tank 3, and water in the water supply tank 3 to the mixing box 4. A circulation path 5 for circulating supply, and a bypass path 6 and a boiler water supply path 7 connected to the circulation path 5 are provided.

  If the boiler 2 is a steam boiler, the structure will not be ask | required in particular, For example, it is a multi-tube type small once-through boiler. The boiler 2 heats the water in the can into steam. This steam is sent to one or a plurality of steam use facilities (not shown). The boiler 2 is provided with a water supply pump (not shown), and water can be taken into the can from the boiler water supply path 7 by this water supply pump. By controlling the water supply pump based on the water level in the can body, the water level in the can body is maintained as desired. In the illustrated example, a plurality of boilers 2 are installed (that is, multiple cans are installed), but the number of boilers 2 is not particularly limited, and only one single can may be installed.

  The water supply tank 3 stores water supplied to the boiler 2. In the present embodiment, the upper opening of the water supply tank 3 is closed by a lid 8, and the lid 8 is provided with a vent 9, and the inside of the water supply tank 3 is opened under atmospheric pressure.

  The water in the water supply tank 3 is typically soft water or pure water. In the present embodiment, the water supply tank 3 is connected with a water supply path 10 from a water softener (not shown) so that water can be supplied appropriately. For example, if the water level in the water supply tank 3 is lower than the lower limit water level, water supply is started from the water supply channel 10, and if the water level is higher than the upper limit water level, water supply from the water supply channel 10 is stopped. Incidentally, the water supply tank 3 is also provided with a temperature sensor 11 for detecting the temperature of the stored water.

  The mixing box 4 is provided in the upper part of the water supply tank 3. The mixing box 4 extends in the up-down direction, the upper end is closed, and the lower end is inserted into the stored water in the water supply tank 3. A watering nozzle (not shown) is provided in the upper part of the mixing box 4, and water from the water supply tank 3 is supplied to the watering nozzle via the circulation path 5. Further, in the mixing box 4, a drain return path 12 from the steam use facility opens below the watering nozzle.

  Therefore, in the mixing box 4, the water in the water supply tank 3 is sprinkled, and the drain from the steam using facility is released under the sprinkling. Thereby, the drain flash vapor can also be condensed, and the high-temperature drain and the flash vapor can be recovered in the feed water tank 3. In this way, energy can be saved by recovering heat.

  The circulation path 5 connects a liquid phase part (particularly preferably at the lower part) of the water supply tank 3 and a watering nozzle of the mixing box 4, and includes a circulation pump 13. By operating the circulation pump 13, the water in the water supply tank 3 is supplied to the watering nozzle of the mixing box 4 via the circulation path 5 to circulate the water between the water supply tank 3 and the mixing box 4. Can do.

  In the circulation path 5, a bypass path 6 is provided downstream from the circulation pump 13. The bypass 6 returns the water from the circulation pump 13 to the water supply tank 3 without going through the mixing box 4.

  A three-way valve 14 as a distribution amount adjusting means is provided at a branch portion between the circulation path 5 and the bypass path 6. With this three-way valve 14, it is possible to adjust the distribution ratio of whether the water from the circulation pump 13 is supplied to the mixing box 4 or returned to the water supply tank 3 through the bypass 6. The circulation path 5 may further include a flow rate adjustment valve 15 downstream of the three-way valve 14. The flow rate adjusting valve 15 is a manual valve whose opening degree can be adjusted in this embodiment.

  In the circulation path 5, a boiler water supply path 7 is branched and provided downstream of the circulation pump 13 and upstream of the three-way valve 14. This boiler water supply path 7 is a water supply path to each boiler 2. If the circulation pump 13 is always operated, water supply to each boiler 2 can be achieved depending on whether or not the water supply pump of each boiler 2 is operated. In that case, the circulation pump 13 functions as a booster pump, without providing a booster pump separately in the boiler water supply path 7. FIG.

  In other words, the circulation pump 13 is a booster pump, and therefore has a larger amount of water supply than the circulation pump of the conventional mixing box. For this reason, when there is no water supply request from the boiler 2, if the entire amount of water from the circulation pump 13 is supplied to the mixing box 4, the flow rate into the mixing box 4 becomes excessive. Therefore, the amount of water supplied to the mixing box 4 can be appropriately maintained by providing the bypass 6 and returning the water from the circulation pump 13 to the water supply tank 3 without going through the mixing box 4 as appropriate.

  The boiler water supply system 1 further includes a control panel 16. In addition to the circulation pump 13, the three-way valve 14, and the temperature sensor 11, each boiler 2 (boiler control panel) is connected to the control panel 16 as desired. The boiler water supply system 1 is controlled by the control panel 16.

  In the boiler water supply system 1 of the present embodiment, the circulation pump 13 is always operated during operation of the boiler 2. The water from the circulation pump 13 is supplied to the mixing box 4 and sprinkled, and the drain from the steam using equipment is opened under the sprinkling, thereby condensing the drain flash steam and recovering heat from the drain and the flash steam. can do.

  The boiler 2 controls its water supply pump so that the water level in the can body is maintained as desired, but water is taken into the boiler 2 from the boiler water supply path 7 by the operation of the water supply pump. At this time, as described above, the circulation pump 13 serves as a booster pump.

  The three-way valve 14 may be maintained at a set opening, but the opening is preferably adjusted so as to maintain a predetermined amount of water supplied to the mixing box 4. That is, by adjusting the opening of the three-way valve 14 so as to maintain a predetermined amount of water supplied to the mixing box 4 regardless of the presence or amount of water supplied to the boiler 2 via the boiler water supply channel 7, The amount of return to the water supply tank 3 via 6 is preferably adjusted. At this time, the water supply request of the boiler 2 can be obtained from each boiler 2, or can be grasped from the flow rate of the boiler water supply path 7, and the opening degree of the three-way valve 14 may be adjusted based on the request. Alternatively, a flow meter may be provided in the circulation path 5 downstream from the three-way valve 14, and the three-way valve 14 may be controlled so that the detected flow rate is maintained at a predetermined level.

  By the way, collection | recovery of the high temperature drain to the water supply tank 3 has a possibility that the water temperature in the water supply tank 3 may rise rather than assumption. Therefore, the water temperature in the water supply tank 3 is monitored by the temperature sensor 11, and when the water temperature in the water supply tank 3 exceeds the upper limit temperature, the three-way valve 14 is controlled, and the entire amount of water from the circulation pump 13 is bypassed. It is good to return to the water supply tank 3 via. Thereby, heat recovery from the drain is temporarily suppressed. If the water temperature in the water supply tank 3 falls below the lower limit temperature, water supply to the mixing box 4 may be resumed to recover heat from the drain and its flash steam.

  In addition, the control panel 16 may be connected to the boiler 2 to notify the user of an abnormality in the boiler water supply system 1 or the boiler 2. Furthermore, the distribution amount by the three-way valve 14 may be adjusted so that the supply water pressure to the boiler 2 is monitored and the supply water pressure is maintained as desired.

  According to the boiler water supply system 1 of the present embodiment, the circulation pump 13 to the mixing box 4 also serves as a booster pump to the boiler 2. Therefore, it is not necessary to separately install a booster pump in addition to the circulation pump 13.

  In addition, a bypass 6 is provided in the circulation path 5 to the mixing box 4 so that water from the circulation pump 13 is supplied to the mixing box 4 or returned to the water supply tank 3 through the bypass 6. Since the ratio is adjusted, the amount of water supplied to the mixing box 4 can be kept appropriate.

  Furthermore, by circulating water between the mixing box 4 and the bypass 6, temperature unevenness in the water supply tank 3 can be reliably prevented.

  FIG. 2 is a schematic view showing a modified example of the boiler water supply system 1 of the present embodiment, and a part thereof is omitted. In the above-described embodiment, the three-way valve 14 is used as the distribution amount adjusting means. However, as in this modification, the circulation path 5 and / or the bypass path 6 downstream from the branch part of the bypass path 6 can be opened or closed. A valve (two-way valve) 17 whose opening degree can be adjusted may be provided. In FIG. 2, a valve 17 that is on / off controlled and switched between open and close and a flow rate adjustment valve 15 that can be manually adjusted in opening degree are provided in series downstream of the branch portion of the bypass passage 6 in the circulation passage 5. . In the case of this modification, the valve 17 and the flow rate adjusting valve 15 constitute a distribution amount adjusting means.

  In the case of FIG. 2, when the valve 17 is opened, the water from the circulation pump 13 is supplied to the mixing box 4 and also to the bypass path 6. The distribution ratio at this time can be adjusted by the flow rate adjusting valve 15. On the other hand, when the temperature sensor 11 detects that the water temperature in the water supply tank 3 has exceeded the upper limit temperature, the valve 17 is closed so that all the water from the circulation pump 13 is supplied to the water supply tank 3 via the bypass 6. Can be returned. Other configurations and controls are the same as those in the above embodiment, and thus the description thereof is omitted.

  The boiler water supply system 1 of the present invention is not limited to the configuration of the above-described embodiment (including modifications thereof) and can be changed as appropriate. For example, in the above embodiment, when the temperature detected by the temperature sensor 11 exceeds the upper limit temperature, the three-way valve 14 is controlled to return all the water from the circulation pump 13 to the water supply tank 3 through the bypass 6. At that time, safety may be further improved as follows. That is, a valve such as an electromagnetic valve is provided downstream of the branch path with the bypass path 6 in the circulation path 5, and when the temperature detected by the temperature sensor 11 exceeds the upper limit temperature, the three-way valve 14 is operated, You may make it close valves, such as the said solenoid valve. Thereby, the water supply to the mixing box 4 can be interrupted more reliably.

DESCRIPTION OF SYMBOLS 1 Boiler water supply system 2 Boiler 3 Water supply tank 4 Mixing box 5 Circulation path 6 Bypass path 7 Boiler water supply path 8 Lid 9 Ventilation hole 10 Water supply path 11 Temperature sensor 12 Drain return path 13 Circulation pump 14 Three-way valve (distribution amount adjustment means)
15 Flow rate adjustment valve (Distribution amount adjustment means)
16 Control panel 17 Valve (Distribution amount adjusting means)

Claims (3)

A water supply tank in which water supply to the boiler is stored;
The water in this water supply tank is circulated and supplied through a circulation path to be sprinkled, and by releasing the drain from the steam using equipment under the sprinkling, a mixing box that condenses and collects the drain flash steam, and
Of the circulation path, provided to branch from the downstream of the circulation pump, a bypass path for returning the water from the circulation pump to the water supply tank without passing through the mixing box;
A distribution amount adjusting means for adjusting a distribution ratio of whether water from the circulation pump is supplied to the mixing box or returned to the water supply tank via the bypass passage;
A boiler water supply system, comprising: a boiler water supply path provided so as to branch from the circulation path downstream from the circulation pump and upstream from a branching section with the bypass path. The distribution amount adjusting means includes a three-way valve provided at a branch portion between the circulation path and the bypass path,
This three-way valve is connected to the water supply tank via the bypass passage so as to maintain a predetermined amount of water supplied to the mixing box regardless of the presence or amount of water supplied to the boiler via the boiler water supply passage. The boiler water supply system according to claim 1, wherein a return amount of the boiler is adjusted. The distribution amount adjusting means returns the entire amount of water from the circulation pump to the water supply tank via the bypass when the water temperature in the water supply tank exceeds the upper limit temperature. Item 3. A boiler water supply system according to Item 2.

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