JP6363291B2 - Hot water generator - Google Patents

Description

  The present application relates to a hot water generator that generates hot water by heating water with steam.

  For example, as disclosed in Patent Document 1, there is known a warm water generating device that generates warm water by heating water with steam. This hot water generator includes a heat exchanger, a header tank, and a drain pumping device. In the heat exchanger, the water supplied from the water supply pipe exchanges heat with the steam supplied from the steam supply pipe to become hot water, and the steam is condensed to drain (condensate). The drain generated in the steam-using device is temporarily stored in the header tank and is pumped to a desired place by the drain pumping device.

Japanese Patent No. 4648430

  By the way, in the warm water generating apparatus as described above, there has been a demand to save energy by reducing the amount of steam supplied to the heat exchanger as much as possible.

  The technology disclosed in the present application has been made in view of such circumstances, and an object thereof is to save energy in a hot water generating apparatus including a heat exchanger that heats water with steam.

  In order to achieve the above object, the technology disclosed in the present application uses the high-temperature heat of the drain generated by the condensation of steam in the heat exchanger to supply water supplied to the heat exchanger (main heat exchanger). I preheated it.

  Specifically, the hot water generator of the present application includes a main heat exchanger, a drain pumping device, and a preheating heat exchanger. In the main heat exchanger, a steam supply pipe and a water supply pipe are connected, and water supplied from the water supply pipe exchanges heat with the steam supplied from the steam supply pipe to become hot water. The drain pumping device is configured to flow in the drain generated by the condensation of steam in the main heat exchanger and pump the drained inflow. The preheating heat exchanger is provided in the middle of the water supply pipe. And the preheating heat exchanger has a container-like body into which the drain pumped from the drain pumping apparatus flows, and a heat transfer pipe provided in the body and through which water of the water supply pipe flows. It is a shell and tube type in which the water in the heat transfer tube is heated by exchanging heat with the drain in the body.

  As described above, according to the hot water generating device of the present application, the water supplied to the main heat exchanger is heated (preheated) by the preheating heat exchanger, so that the steam supply amount in the main heat exchanger is reduced. Can do. Moreover, in the preheating heat exchanger, water is heated (preheated) by the high-temperature drain generated in the main heat exchanger, so that water can be heated using exhaust heat. That is, heat recovery can be performed. As described above, the hot water generator of the present application can save energy.

  Furthermore, in the preheating heat exchanger, the drain pumped from the drain pumping device is allowed to flow into the body (shell) instead of the heat transfer tube (tube). Therefore, compared with the case where the drain from a drain pumping apparatus flows in into a heat exchanger tube, the required pumping force in a drain pumping apparatus can be reduced. That is, in the shell-and-tube type preheating heat exchanger, the trunk (shell) has a larger flow path than the heat transfer tube (tube), so the flow resistance is small. Therefore, in the drain pumping device, the pumping force required for the pumping is smaller when the drain is pumped to the body than when the drain is pumped to the heat transfer tube. As described above, in the hot water generating device of the present application, the necessary pumping force of the drain pumping device is reduced, so that the energy for generating the pumping force can be reduced. Thereby, further energy saving can be achieved.

FIG. 1 is a piping diagram illustrating a schematic configuration of a hot water generator according to an embodiment. FIG. 2 is a plan view showing the internal configuration of the preheating heat exchanger according to the embodiment as viewed from above. 3 is a cross-sectional view taken along line AA in FIG.

  Hereinafter, embodiments of the present application will be described with reference to the drawings. Note that the following embodiments are essentially preferable examples, and are not intended to limit the scope of the technology disclosed in the present application, applications thereof, or uses thereof.

  As shown in FIG. 1, the hot water generator 1 of this embodiment includes a steam supply system 10, a water heating system 20, and a drain discharge system 30. In addition, the piping system diagram of FIG. 1 schematically shows the connection relationship of each device, and unless otherwise specified below, the connection location of the pipe in each device and the installation height of each device are specifically shown. It is not shown.

  The steam supply system 10 supplies steam that is a heating medium to the water heating system 20. The steam supply system 10 is connected to a water heating system 20 and includes a steam supply pipe 11 that supplies steam. The steam supply pipe 11 is provided with an on-off valve 12, a control valve 13, and an electromagnetic valve 15 in order from the upstream side. The control valve 13 has a gas-liquid separation unit 14 that separates vapor that is gas and drain that is liquid, and the vapor separated by the gas-liquid separation unit 14 flows downstream. That is, the control valve 13 is configured to flow only steam downstream. The control valve 13 is a flow rate adjustment valve that can adjust the flow rate of steam.

  The water heating system 20 includes a main heat exchanger 22 and a preheating heat exchanger 28. The main heat exchanger 22 has a water supply pipe 21 connected to the inlet side (upstream side) and a hot water delivery pipe 23 connected to the outlet side (downstream side). Further, the steam supply pipe 11 of the steam supply system 10 is connected to the main heat exchanger 22. The main heat exchanger 22 is a so-called shell-and-tube heat exchanger, and cold water (water) is supplied from the water supply pipe 21 and steam is supplied from the steam supply pipe 11. In the main heat exchanger 22, the supplied cold water is heated by exchanging heat with steam to become hot water having a predetermined temperature. On the other hand, the steam condenses and becomes drain (condensate). That is, the main heat exchanger 22 is a latent heat exchanger in which cold water is heated by the latent heat of condensation of steam. The hot water thus generated in the main heat exchanger 22 flows through the hot water delivery pipe 23 and is sent to the use side. A water reservoir 24 for storing cold water is provided on the inlet side of the main heat exchanger 22.

  The preheating heat exchanger 28 is provided in the middle of the water supply pipe 21, and heats (preheats) the cold water in the water supply pipe 21 supplied to the main heat exchanger 22. Details of the preheating heat exchanger 28 will be described later.

  The water heating system 20 includes a circulation pipe 25, a circulation pump 26, and an electromagnetic valve 27. One end of the circulation pipe 25 is connected to the upstream side of the preheating heat exchanger 28 in the water supply pipe 21, and the other end is connected to the hot water delivery pipe 23. The circulation pump 26 and the electromagnetic valve 27 are provided in the circulation pipe 25 in order from the water supply pipe 21 side. In the water heating system 20, the solenoid valve 27 is opened and the circulation pump 26 is driven, so that the hot water in the main heat exchanger 22 is supplied to the water reservoir 24, the preheating heat exchanger 28, the circulation pipe 25, and the hot water delivery pipe 23. The circulating operation of the hot water that passes through the main heat exchanger 22 again is performed. In addition, you may make it perform this circulating operation of warm water in the reverse direction to the circulation direction mentioned above.

  The drain discharge system 30 includes a header tank 32 and a drain pumping device 34, and discharges high-temperature drain generated by condensation of steam in the main heat exchanger 22. The header tank 32 is a cylindrical container extending in the horizontal direction, and is connected to the main heat exchanger 22 via a drain discharge pipe 31. The drain discharge pipe 31 is connected to the upper part of the header tank 32. In the header tank 32, the drain of the main heat exchanger 22 flows through the drain discharge pipe 31 and is temporarily stored.

  The drain pressure feeding device 34 is configured to flow in the drain of the header tank 32 and pump the drained inflow. Specifically, the drain pumping device 34 has a drain inlet 34a and a pumping port 34b, and a steam inlet 34c and a outlet 34d. The inflow port 34 a is connected to the header tank 32 through the drain inflow pipe 33. The drain inflow pipe 33 is connected to the bottom of the header tank 32. The pressure feed port 34 b is connected to the preheating heat exchanger 28 via the drain pressure feed pipe 35. The drain discharge system 30 includes a drain discharge pipe 36 that is connected to the preheating heat exchanger 28 and that discharges the drain from the preheating heat exchanger 28. The drain inflow pipe 33 and the drain pressure feed pipe 35 are provided with check valves 37 and 38. The check valve 37 allows only the flow of fluid from the header tank 32 toward the drain pumping device 34 in the drain inflow pipe 33. The check valve 38 allows only the flow of fluid from the drain pumping device 34 in the drain pumping pipe 35 toward the preheating heat exchanger 28. The introduction port 34 c is connected to the gas-liquid separation unit 14 of the control valve 13 through a steam introduction pipe 39. The steam introduction pipe 39 is provided with a strainer 42 and a pressure reducing valve 43 in order from the gas-liquid separation unit 14 side. The discharge port 34 d is connected to the drain discharge pipe 31 through the steam discharge pipe 41.

  Although not shown, the drain pumping device 34 has a drain storage chamber, and a float is disposed in the storage chamber. The drain pumping device 34 is configured such that when the float is lowered to a predetermined low level, the introduction port 34c is closed and the discharge port 34d is opened, and when the float is raised to a predetermined high level, the introduction port 34c is opened and the discharge port 34d is closed. Has been. In the drain pumping device 34, when the inlet 34c is closed and the outlet 34d is opened, the drain of the header tank 32 flows into the storage chamber from the inlet 34a through the drain inlet pipe 33. As the drain flows, the steam in the storage chamber is discharged from the discharge port 34d to the steam discharge pipe 41. Further, in the drain pumping device 34, when the introduction port 34c is opened and the discharge port 34d is closed, the vapor of the gas-liquid separator 14 flows into the storage chamber from the introduction port 34c through the vapor introduction pipe 39. By introducing this steam, the drain in the storage chamber is pumped (discharged) from the pumping port 34b to the drain pumping pipe 35. In this way, the drain pumping device 34 pumps the drain of the header tank 32 (that is, drain generated by condensing steam in the main heat exchanger 22).

  Further, the drain discharge system 30 is provided with two drain discharge pipes 45 and 48 and an air vent pipe 49. One end (inflow end) of the drain discharge pipe 45 is connected to the downstream side of the pressure reducing valve 43 in the steam introduction pipe 39, and the other end (outflow end) is connected to the drain discharge pipe 36. The drain discharge pipe 45 is provided with a steam trap 46 and a check valve 47 in order from the steam introduction pipe 39 side. The steam trap 46 automatically discharges only the drain to the downstream side. By providing such a drain discharge pipe 45 and the steam trap 46, even when drain flows into the steam introduction pipe 39 together with the steam from the gas-liquid separator 14, only the drain is discharged from the steam introduction pipe 39 through the drain discharge pipe 45. be able to. The check valve 47 allows only the flow of fluid from the steam introduction pipe 39 to the drain discharge pipe 36 in the drain discharge pipe 45.

  One end (inflow end) of the drain discharge pipe 48 is connected to the gas-liquid separator 14 of the control valve 13, and the other end (outflow end) is connected between the steam trap 46 and the check valve 47 in the drain discharge pipe 45. Has been. The drain discharged from the gas / liquid separator 14 is discharged from the drain discharge pipe 48. The air vent pipe 49 has one end (inflow end) connected to the upper portion of the header tank 32 and the other end (outflow end) connected to the drain discharge pipe 48. The air vent pipe 49 is provided with an air vent 51 and a check valve 52 in order from the header tank 32 side. The check valve 52 allows only the flow of fluid from the header tank 32 toward the drain discharge pipe 48. The air vent tube 49 discharges the initial air in the header tank 32. In addition to the drain pumping pipe 35, a drain discharge pipe 53 for discharging the drain of the storage chamber is connected to the drain pumping apparatus 34. The drain discharge pipe 53 is provided with a blow valve 54.

  Furthermore, the hot water generator 1 of this embodiment includes a flow switch 61, a temperature sensor 62, two pressure gauges 63 and 64, and a control unit 70. The flow switch 61 is provided on the upstream side of the preheating heat exchanger 28 in the water supply pipe 21 and detects the flow of cold water. The temperature sensor 62 is provided on the upstream side of the connection portion 17 of the circulation pipe 25 in the hot water delivery pipe 23, and detects the temperature of the hot water. The two pressure gauges 63 and 64 are provided on the upstream side and the downstream side of the pressure reducing valve 43 in the steam introduction pipe 39. The control unit 70 controls the control valve 13, the electromagnetic valve 15, and the like based on detection signals from the flow switch 61 and the temperature sensor 62. Specifically, it is as follows.

  The control unit 70 adjusts the opening degree of the control valve 13 so that the temperature detected by the temperature sensor 62 (temperature of hot water) becomes the set temperature. For example, when the detected temperature (temperature of hot water) of the temperature sensor 62 becomes higher than the set temperature, the opening degree of the control valve 13 is reduced, and when the detected temperature of the temperature sensor 62 becomes lower than the set temperature, the opening degree of the control valve 13. Is increased. Further, the controller 70 closes the electromagnetic valve 15 in an emergency. For example, when the detected temperature of the temperature sensor 62 becomes higher than the set temperature by a predetermined temperature or more because the opening degree of the control valve 13 reaches the lower limit value or due to a failure of the control valve 13, the electromagnetic valve 15 is closed. Further, when the use of hot water is stopped (that is, when the outflow of hot water from the main heat exchanger 22 to the hot water delivery pipe 23 is stopped), the temperature detected by the temperature sensor 62 is higher than the set temperature by a predetermined temperature or more. If the flow switch 61 no longer detects the flow of cold water, the solenoid valve 15 is closed. By closing the electromagnetic valve 15 in this way, it is possible to prevent the temperature of the hot water from becoming abnormally high, and it is possible to avoid wasteful supply of steam to the main heat exchanger 22.

  In an emergency, the control unit 70 controls the circulation pump 26 and the electromagnetic valve 27 of the circulation pipe 25 in combination with the above-described control of the electromagnetic valve 15 or alone. That is, when the use of hot water is stopped, when the temperature detected by the temperature sensor 62 becomes higher than the set temperature by a predetermined temperature or when the flow of cold water is no longer detected by the flow switch 61, the solenoid valve 27 is opened and circulated. The pump 26 is driven. Then, as described above, the hot water circulation operation in which the hot water in the main heat exchanger 22 returns to the main heat exchanger 22 again through the water reservoir 24, the preheating heat exchanger 28, the circulation pipe 25, and the hot water delivery pipe 23. Is forced. Thereby, since it can prevent that warm water retains in the main heat exchanger 22, it can suppress that warm water is heated more than preset temperature with the steam which remain | survives in the main heat exchanger 22. FIG. Moreover, in the above-described warm water circulation operation, the temperature of the hot water is lowered by passing the hot water through the water reservoir 24, so that it is possible to further suppress the warm water from reaching the set temperature. And when utilization of warm water is restarted, the comparatively low temperature warm water which flows from the circulation pipe 25 to the warm water delivery pipe 23 can be sent to a utilization side preferentially.

<Configuration and action of preheating heat exchanger>
The preheating heat exchanger 28 is a so-called shell-and-tube heat exchanger, and is provided in the middle of the water supply pipe 21 as described above. As shown in FIGS. 2 and 3, the preheating heat exchanger 28 has a body 28 a (shell) and a plurality of heat transfer tubes 28 b (tubes). The body 28a is a cylindrical container extending in the horizontal direction and in the upstream and downstream directions. The plurality of heat transfer tubes 28b are straight tubes and are provided inside the body 28a. The heat transfer tube 28b is provided so as to extend in the upstream / downstream direction. The body 28a is provided with a drain inlet 28e and a discharge outlet 28f, a drain pressure feed pipe 35 is connected to the inlet 28e, and a drain discharge pipe 36 is connected to the discharge outlet 28f. The body 28a is formed with an inflow chamber 28c communicating with the water supply pipe 21 on the inlet side (upstream side) and an outflow chamber 28d communicating with the water supply pipe 21 on the outlet side (downstream side). . One end (inflow end) of the plurality of heat transfer tubes 28b communicates with the inflow chamber 28c, and the other end (outflow end) communicates with the outflow chamber 28d.

  In the preheating heat exchanger 28, high-temperature drain is pumped (inflows) from the drain pumping device 34 into the body 28 a through the drain pumping pipe 35. On the other hand, in the preheating heat exchanger 28, the cold water in the water supply pipe 21 flows into the inflow chamber 28c and flows into the plurality of heat transfer pipes 28b. In the preheating heat exchanger 28, the cold water flowing through the heat transfer tube 28b is heated (preheated) by exchanging heat with the drain in the body 28a. The cooled cold water in the heat transfer tube 28 b flows from the outflow chamber 28 d to the water supply tube 21 and flows into the main heat exchanger 22. On the other hand, the drain in the body 28 a that has exchanged heat with the cold water in the heat transfer tube 28 b is discharged to the drain discharge tube 36. Thus, in the hot water generator 1 of the present embodiment, the cold water is preheated (heated up) before flowing into the main heat exchanger 22.

  Further, in the body 28 a of the preheating heat exchanger 28, the drain inlet 28 e and the outlet 28 f are provided at a substantially central position in the vertical direction (vertical direction). That is, in the body 28a, the inlet 28e and the outlet 28f are provided at the same height. Some of the drain pumped from the drain pumping device 34 is re-evaporated (flashed) while flowing through the drain pumping pipe 35, so that some steam flows into the body 28a together with the drain. In the body 28a, the drain is located at the lower part and the steam is located at the upper part. Therefore, in the preheating heat exchanger 28, the cold water in the heat transfer tube 28b located at the lower portion substantially exchanges heat with the drain, and the cold water in the heat transfer tube 28b located at the upper portion substantially exchanges heat with the steam. Here, since the heat transfer coefficient of the steam is higher than the heat transfer coefficient of the drain, the heat exchange efficiency between the drain, the steam, and the cold water can be increased by increasing the volume occupied by the steam in the body 28a as much as possible.

  In this respect, in the preheating heat exchanger 28 of the present embodiment, the drain discharge port 28f is provided at a substantially central position in the vertical direction of the body 28a as described above, so that the drain discharge port and the like are temporarily provided above the body 28a. Compared with the case where it provides, the volume which a vapor | steam occupies in the fuselage | body 28a can fully be earned. That is, since the discharge port 28f is provided at a substantially central position in the vertical direction in the body 28a, the drain is not stored in the body 28a beyond the height at which the discharge port 28f is positioned. Therefore, in the present embodiment, drain occupies the lower half of the body 28a, and steam occupies the upper half of the body 28a.

  Further, in the preheating heat exchanger 28 of the present embodiment, the drain inlet 28e and the outlet 28f are provided at the same height as the pumping port 34b of the drain pumping device 34. That is, the drain pumping pipe 35 extends horizontally from the pumping port 34 b of the drain pumping device 34 and is connected to the inlet 28 e of the preheating heat exchanger 28. In this way, for example, the necessary pumping force in the drain pumping device 34 is reduced as compared with the case where the drain inlet is provided at a position higher than the pumping port 34 b of the drain pumping device 34.

  As described above, according to the hot water generator 1 of the above embodiment, the water supplied to the main heat exchanger 22 is heated (preheated) by the preheating heat exchanger 28, and thus the main heat is supplied from the steam supply pipe 11. The amount of steam supplied to the exchanger 22 can be reduced. Moreover, in the preheating heat exchanger 28, water is heated (preheated) by the high-temperature drain generated in the main heat exchanger 22, so that the water can be heated using exhaust heat. That is, heat recovery can be performed. As described above, the hot water generator 1 of the above embodiment can save energy.

  Further, in the preheating heat exchanger 28 of the above embodiment, the drain pumped from the drain pumping device 34 is caused to flow into the body 28a (shell) instead of the heat transfer tube 28b (tube). Therefore, compared with the case where the drain from the drain pumping apparatus 34 is made to flow in into the heat exchanger tube 28b, the required pumping force in the drain pumping apparatus 34 can be reduced. That is, in the shell-and-tube type preheating heat exchanger 28, the trunk body 28a has a larger flow path than the heat transfer tube 28b, and thus the flow resistance is small. Therefore, in the drain pumping device 34, the pumping force required for the pumping can be reduced by pumping the drain to the body 28a rather than pumping the drain to the heat transfer tube 28b. As described above, in the hot water generating device 1 of the above embodiment, the necessary pumping force of the drain pumping device 34 can be reduced, so that energy for generating the pumping force can be reduced. Thereby, further energy saving can be achieved.

  Further, in the preheating heat exchanger 28 of the above-described embodiment, the drain outlet 28f of the body 28a is provided at a substantially central position in the vertical direction. Therefore, the volume occupied by the steam in the body 28a can be earned as much as possible. Thereby, the heat exchange efficiency of the drain, steam, and water in the preheating heat exchanger 28 can be increased as much as possible. If it does so, the flow volume of the drain supplied to the preheating heat exchanger 28 from the drain pumping apparatus 34 can be reduced, and energy saving can be achieved further.

  Further, in the preheating heat exchanger 28 of the above-described embodiment, the drain inlet 28e is provided at the same height as the outlet 28f in the body 28a (that is, at a substantially central position in the vertical direction). By doing so, the drain and steam from the drain pumping pipe 35 can be caused to flow near the water surface of the drain stored in the body 28a. As a result, the drain from the drain pumping pipe 35 is guided directly to the drain region in the body 28a, and the steam from the drain pumping pipe 35 is guided directly to the steam region in the body 28a. For example, when the inflow port is provided at a position lower than the discharge port, the steam from the drain pumping pipe 35 passes through the drain region in the body 28a and is guided to the steam region. Then, when the steam passes through the drain region, it condenses by exchanging heat with the drain, and the steam is lost (steam loss). In this regard, in the above-described embodiment, the steam from the drain pumping pipe 35 is directly guided to the steam region in the body 28a, so that the steam loss described above can be prevented.

  In the above embodiment, the positions of the inlet 28e and the outlet 28f of the body 28a of the preheating heat exchanger 28 may be lower or higher than the positions described above.

  The technology disclosed in the present application is useful for a hot water generating device including a heat exchanger that generates hot water by heating water with steam.

DESCRIPTION OF SYMBOLS 1 Hot water production | generation apparatus 11 Steam supply pipe 21 Water supply pipe 22 Main heat exchanger 28 Preheating heat exchanger 28a Body 28b Heat transfer pipe 28e Inlet 28f Outlet 34 Drain pressure feeder

Claims (1)

A main heat exchanger to which a steam supply pipe and a water supply pipe are connected, and water supplied from the water supply pipe exchanges heat with the steam supplied from the steam supply pipe to become hot water;
Drain generated by condensing steam in the main heat exchanger flows in, and a drain pumping device that pumps the drain that flows in,
A container-like body that is provided in the middle of the water supply pipe and into which the drain pumped from the drain pumping apparatus flows, and a heat transfer pipe that is provided in the body and through which the water of the water supply pipe flows. And a shell-and-tube preheating heat exchanger in which water in the heat transfer tube is heated by exchanging heat with the drain in the fuselage ,
In the fuselage of the preheating heat exchanger,
A drain outlet is provided at a substantially central position in the vertical direction,
A hot water generating device , wherein an inlet of a drain pumped from the drain pumping device is provided at a position having the same height as the discharge port .

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