Liquid supply device

Abstract

To efficiently cool or heat circulating liquid and supply the same to a use point.SOLUTION: A liquid supply device 1 includes: a tank 2 that stores liquid; a supply line L21 that supplies the liquid from the tank 2 to a use point 3; a pump 21 that is provided in the supply line L21 and circulates the liquid in the tank 2 to the supply line L21; a heat exchanger 22 that is provided in the supply line L21 on a downstream side of the pump 21 and cools or heats the liquid supplied to the use point 3 and used, to a temperature different from that of the liquid in the tank 2; and a reflux line L22 that refluxes liquid that is not used at the use point 3 out of the liquid supplied to the use point 3 through the supply line L21 to the supply line L21 on an upstream side of the pump 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid supply device.

Background Art

[0002] As a device for supplying purified water used in pharmaceutical production to the use point, in order to suppress the generation of viable bacteria due to the retention of purified water, a circulation operation is performed to constantly circulate purified water between the tank and the use point regardless of the presence or absence of demand at the use point (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Among such devices, in order to correspond to the required temperature at the use point set lower or higher than room temperature, there are some equipped with a heat exchanger having a cooling or heating mechanism on the circulation path. In this case, while the purified water cooled or heated to the required temperature at the use point flows back to the tank storing the purified water, purified water at room temperature is replenished as needed. Therefore, each time, the temperature of the purified water in the tank deviates from the required temperature at the use point. And cooling or heating the purified water in such a tank to the required temperature at the use point leads to unnecessary energy consumption.

[0005] Therefore, an object of the present invention is to provide a liquid supply device that efficiently cools or heats the circulating liquid and supplies it to the use point.

Means for Solving the Problems

[0006] To achieve the above-mentioned objectives, the liquid supply device of the present invention comprises a tank for storing liquid, a supply line for supplying liquid from the tank to a point of use, and a device provided in the supply line. Ta A pump; a heat exchanger located in the supply line downstream of the pump, which cools or heats the liquid supplied to the point of use to a temperature different from the liquid in the tank; a recirculation line that recirculates the liquid supplied to the point of use through the supply line that is not used at the point of use back to the supply line upstream of the pump; and a discharge line connected to the recirculation line at a position close to the downstream end of the recirculation line, which discharges the liquid in the supply line and the recirculation line to the outside. A separate supply line that supplies liquid from the tank to the point of use, a separate pump installed on the separate supply line, and a separate recirculation line that recirculates the liquid supplied to the point of use through the separate supply line that is not used at the point of use back to the tank. It has.

[0007] Such a liquid supply device makes it possible to circulate liquid without using a tank, allowing the circulating liquid to be cooled or heated with minimal energy. [Effects of the Invention]

[0008] As described above, according to the present invention, circulating liquid can be efficiently cooled or heated and supplied to the point of use. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing the configuration of a purified water supply device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In this specification, a purified water supply device that supplies purified water used in pharmaceutical manufacturing to a point of use is given as an example of the liquid supply device of the present invention, but the present invention is not limited thereto and can also be applied to devices that supply water (liquid) such as deionized water, ultrafiltered water (water obtained by treating purified water or deionized water with an ultrafiltration membrane), and water for injection to a point of use, which are used in pharmaceutical manufacturing.

[0011] Figure 1 is a schematic diagram showing the configuration of a purified water supply device according to one embodiment of the present invention. Note that the configuration of the purified water supply device shown is merely an example and does not limit the present invention.

[0012] The purified water supply device 1 includes a tank 2 for storing purified water, a room temperature water supply unit 10, and a low temperature water supply unit 20. In this embodiment, two types of required temperatures are set at the use point 3: room temperature (e.g., 25°C) and a lower temperature (e.g., 5°C). Therefore, as will be described in detail later, the room temperature water supply unit 10 is configured to supply the purified water in the tank 2 to the use point 3 at room temperature, while the low temperature water supply unit 20 is configured to cool the purified water in the tank 2 to a temperature lower than room temperature before supplying it to the use point 3. Hereafter, in order to distinguish between the two types of purified water supplied to the use point 3, the purified water at room temperature will be referred to as "room temperature water," and the purified water at a lower temperature will be referred to as "low temperature water." Furthermore, the purified water supply device 1 has a control unit (control means) 4 that controls the operation of the purified water supply device 1.

[0013] The ambient water supply unit 10 includes an ambient water circulation line L10 for circulating ambient water and an ambient water pump 11 provided on the ambient water circulation line L10. The ambient water circulation line L10 includes an ambient water supply line L11 that connects the tank 2 and the inlet 3a of the use point 3 and is equipped with the ambient water pump 11, and an ambient water return line L12 that connects the outlet 3b of the use point 3 and the tank 2. The use point 3 is provided with an ambient water supply line L1 that is connected to the ambient water circulation line L10 via an on-off valve V1. The number of ambient water supply lines L1 is not limited to one, but may be multiple.

[0014] With this configuration, ambient temperature water in tank 2 is supplied to use point 3 via ambient temperature water supply line L11 by ambient temperature water pump 11, and ambient temperature water not used at use point 3 is returned to tank 2 via ambient temperature water return line L12. In this way, a circulation operation is performed in which ambient temperature water is circulated through tank 2, and ambient temperature water is consumed at use point 3 as needed.

[0015] The low-temperature water supply unit 20 includes a low-temperature water circulation line L20 for circulating low-temperature water, a low-temperature water pump 21 provided on the low-temperature water circulation line L20, and a heat exchanger 22 also provided on the low-temperature water circulation line L20. The low-temperature water circulation line L20 includes a low-temperature water supply line L21 that connects the tank 2 and the inlet 3c of the use point 3 and is equipped with the low-temperature water pump 21 and the heat exchanger 22, and a low-temperature water return line L22 that connects the outlet 3d of the use point 3 and the low-temperature water supply line L21 upstream of the low-temperature water pump 21. The heat exchanger 22 has the function of cooling the purified water flowing through the low-temperature water supply line L21 to a predetermined temperature to produce low-temperature water. The use point 3 is provided with a low-temperature water supply line L2 connected to the low-temperature water circulation line L20 via an on-off valve V2. The number of low-temperature water supply lines L2 is not limited to one, but may be multiple.

[0016] In this configuration, the chilled water pumped by the chilled water pump 21 and cooled to a predetermined temperature in the heat exchanger 22 is supplied to the use point 3 through the chilled water supply line L21, and any chilled water not used at the use point 3 is returned to the chilled water supply line 21 through the chilled water return line L22. In this way, a circulation operation is performed that circulates the chilled water without going through the tank 2, and chilled water is consumed at the use point 3 as needed. In this chilled water circulation operation, the chilled water from the chilled water return line L22 is not returned to the tank 2 as described above, but is combined with ambient temperature water supplied from the tank 2 as needed and supplied to the heat exchanger 22. That is, when the flow rate of the chilled water supply line L21 fluctuates according to the amount used at the use point 3, ambient temperature water is supplied from the tank 2 to the chilled water supply line L21 accordingly, and chilled water from the chilled water return line L22 is combined with this ambient temperature water and supplied to the heat exchanger 22. The supply of ambient temperature water from tank 2 is performed by the pressure difference between the pressure inside tank 2 and the pressure in the low-temperature water supply line L21, or by the suction pressure of the pump. In this way, the temperature rise of the low-temperature water supplied to the heat exchanger 22 can be minimized, and the energy required to produce the low-temperature water can be minimized. This is also preferable because it allows for the use of a heat exchanger 22 with a small cooling capacity, which leads to cost reduction.

[0017] The ambient water recirculation line L12 is equipped with an ultraviolet sterilizer 12 and a heat exchanger (not shown). The ultraviolet sterilizer 12 is used to sterilize the ambient water flowing through the ambient water recirculation line L12 by ultraviolet irradiation. The heat exchanger is used in a hot water sterilization process that is performed periodically between normal operations. It is used to generate hot water by heating purified water circulating along the ambient water circulation line L10 to a predetermined temperature or higher, for example, 80-90°C, and to sterilize the tank 2 and the ambient water circulation line L10 with this hot water. The ambient water circulation operation is performed even during periods when there is no demand for ambient water at use point 3, such as at night or on holidays. However, if this continues for a long period of time, the temperature of the ambient water may rise due to the heat generated by the ambient water pump 11 and the ultraviolet sterilizer 12, potentially exceeding the required temperature at use point 3. For this reason, the heat exchanger for hot water sterilization described above may have a cooling function, or a separate heat exchanger with a cooling function may be provided in the ambient water circulation line L10.

[0018] A shut-off valve V11 is provided downstream of the ultraviolet sterilizer 12 in the ambient temperature water recirculation line L12, and an ambient temperature water discharge line L13 is connected between the shut-off valve V11 and the ultraviolet sterilizer 12 via the shut-off valve V12. When ambient temperature water is circulated, the shut-off valve V11 of the ambient temperature water recirculation line L12 is opened and the shut-off valve V12 of the ambient temperature water discharge line L13 is closed, so ambient temperature water tends to accumulate in the portion of the ambient temperature water discharge line L13 upstream of the shut-off valve V12. On the other hand, when ambient temperature water is discharged, the shut-off valve V11 of the ambient temperature water recirculation line L12 is closed and the shut-off valve V12 of the ambient temperature water discharge line L13 is opened, so ambient temperature water tends to accumulate in the portion of the ambient temperature water recirculation line L12 from the connection point with the ambient temperature water discharge line L13 to the shut-off valve V11. To minimize the effects of such dead legs, it is preferable, for example, that the distance from the center of the main pipe to the closing mechanism at the end of the branch pipe be within six times the inner diameter of the branch pipe. That is, the distance from the center of the ambient water return line L12 at the connection point with the ambient water discharge line L13 to the closed position of the on-off valve V12 is preferably within six times the inner diameter of the ambient water discharge line L13. Similarly, the distance from the center of the ambient water discharge line L13 at the connection point with the ambient water return line L12 to the closed position of the on-off valve V11 is also preferably within six times the inner diameter of the ambient water return line L12.

[0019] The low-temperature water reflux line L22 is provided with an ultraviolet sterilizer 23, similar to the normal-temperature water reflux line L12. The ultraviolet sterilizer 23 is used to sterilize the low-temperature water flowing through the low-temperature water reflux line L22 by irradiating it with ultraviolet light. However, the growth rate of live bacteria is slower in low-temperature water than in normal-temperature water. If the normal-temperature water in the tank 2, which is also the water intake source of the low-temperature water supply unit 20, has already been sterilized, it is not necessarily required to perform ultraviolet sterilization on the low-temperature water. Therefore, the ultraviolet sterilizer 23 may be omitted. Also, in the low-temperature water circulation line L20, a hot water sterilization process similar to that in the normal-temperature water circulation line L10 is performed. Therefore, in order to heat the purified water circulating along the low-temperature water circulation line L20 to a temperature above the above-mentioned predetermined temperature to generate hot water, the above-described heat exchanger 22 may have a heating function, or a heat exchanger with a separate heating function may be provided in the low-temperature water circulation line L20. Note that since the heat exchanger 22 for cooling is always provided in the low-temperature water supply unit 10, there is no concern about the temperature rise of the low-temperature water due to the heat generation of the low-temperature water pump 21 or the ultraviolet sterilizer 22, even when the circulation operation of the low-temperature water lasts for a long time.

[0020] Also, the low-temperature water reflux line L22 is provided with a pressure sensor 24, a temperature sensor 25, and a flow sensor 26. These are used not only for the purpose of grasping the usage status of the low-temperature water at the use point 3, but also for the operation control of the purified water supply device 1 by the control unit 4, as will be described later.

[0021] The cold water recirculation line L22 is connected to the cold water supply line L21 via an on-off valve V21. Upstream of this connection point, specifically near the downstream end of the cold water recirculation line L22, the cold water discharge line L23 is connected via an on-off valve V22. During cold water circulation, the on-off valve V21 of the cold water recirculation line L22 is opened, and the on-off valve V22 of the cold water discharge line L23 is closed (i.e., the on-off valves V21 and V22, which act as flow path switching means, are switched to the first state), thereby connecting the cold water recirculation line L22 and the cold water supply line L21. As a result, cold water tends to accumulate in the portion of the cold water discharge line L23 upstream of the on-off valve V22. On the other hand, when cold water is drained, the shut-off valve V21 of the cold water return line L22 is closed, and the shut-off valve V22 of the cold water discharge line L23 is opened (i.e., the shut-off valves V21 and V22, which act as flow path switching means, are switched to a second state), thereby connecting the cold water return line L22 and the cold water discharge line L23. As a result, cold water tends to accumulate in the portion of the cold water return line L22 from the connection point with the cold water discharge line L23 to the shut-off valve V21, and in the portion downstream of the shut-off valve V21. In order to minimize the effects of such dead legs, as described above, it is preferable that, for example, the distance from the center of the main pipe to the closing mechanism at the end of the branch pipe be within six times the inner diameter of the branch pipe. That is, it is preferable that the distance from the center of the cold water return line L22 at the connection point with the cold water discharge line L23 to the closed position of the shut-off valve V22 be within six times the inner diameter of the cold water discharge line L23. Similarly, the distance from the center of the cold water supply line L21 at the connection point with the cold water return line L22 to the closed position of the shut-off valve V21, and the distance from the center of the cold water discharge line L23 at the connection point with the cold water return line L22 to the shut-off valve V2 1 The distance to the closed position is preferably within six times the inner diameter of the low-temperature water recirculation line L22.

[0022] Note that a purified water supply line L3 is connected to the tank 2, and purified water is supplied from a purified water production device (not shown) according to the water level in the tank 2 detected by, for example, a water level sensor (not shown). Specifically, when the water level in the tank 2 falls below a predetermined lower limit water level, purified water is supplied to the tank 2 through the purified water supply line L3, and when the water level in the tank 2 reaches the predetermined upper limit water level, the supply of purified water to the tank 2 is stopped.

[0023] The control unit 4 includes an inverter (not shown) that controls the rotation speed of the low-temperature water pump 21, and performs flow rate control of the low-temperature water by controlling the rotation speed of the low-temperature water pump 21 during normal operation (purified water circulation operation) of the purified water supply device 1. Specifically, based on the flow rate of the low-temperature water detected by the flow rate sensor 26, the rotation speed of the low-temperature water pump 21 is controlled so that the flow rate of the low-temperature water flowing through the low-temperature water reflux line L22 becomes constant. By such flow rate control of the low-temperature water, the flow rate of the low-temperature water supplied to the heat exchanger 22 can be stabilized, the cooling capacity of the heat exchanger 22 can be stably exhibited, and low-temperature water can be supplied to the use point 3 at a stable temperature. As the low-temperature water flow rate detection means, a pressure sensor 24 may be used instead of the flow rate sensor 26, and therefore, the rotation speed of the low-temperature water pump 21 may be controlled so that the detected pressure becomes constant. Further, the low-temperature water flow rate adjustment means is not limited to the low-temperature water pump 21, and a flow rate adjustment valve may be provided in the low-temperature water reflux line L22. Although not described in detail here, the control unit 4 controls the rotation speed of the normal-temperature water pump 11 based on the detection result of a flow rate sensor or a pressure sensor (both not shown) provided in the normal-temperature water reflux line L12, and also performs normal-temperature water flow rate control to maintain a constant flow rate of the normal-temperature water flowing through the normal-temperature water reflux line L12.

[0024] During the circulation operation of the cold water, the return pressure of the cold water return line L22 (the pressure detected by the pressure sensor 24) is adjusted so that ambient temperature water can be smoothly supplied from the tank 2 to the pump 21, and so that the cold water return line L22 does not become negative pressure. As a result, ambient temperature water is automatically supplied from the tank 2 to the cold water supply line L21 without the need to install valves or pumps between the tank 2 and the confluence point of the cold water supply line L21 and the cold water return line L22. The pressure detected by the pressure sensor 24 is preferably adjusted to a range of 0.01 to 0.2 MPa, and more preferably to a range of 0.05 to 0.15 MPa. This is because if the pressure detected by the pressure sensor 24 is controlled to less than 0.01 MPa, the control may not be able to keep up when cold water is used at use point 3, and the cold water return line L22 may become negative pressure. Furthermore, if the return pressure in the low-temperature water recirculation line L22 becomes too high, it may become difficult to smoothly supply room-temperature water from tank 2 to pump 21, ultimately potentially causing disturbances in the pressure detected by pressure sensor 24. However, the ease with which room-temperature water can be supplied from tank 2 to pump 21 also depends on the hydrostatic pressure from tank 2 and the pressure loss of the on-off valve V21 (opening degree of on-off valve V21), so the above-mentioned pressure range does not limit the present invention.

[0025] Incidentally, in a purified water supply system 1 that handles purified water used in pharmaceutical manufacturing, it is preferable to sterilize the system, including the tank 2 and each circulation line L10, 20, with steam in order to prevent the growth of bacteria and microorganisms. For this purpose, a steam introduction line (steam introduction means) L4 is connected to the tank 2, and the control unit 4 periodically performs steam sterilization in between normal operations. The steam sterilization process will be described below.

[0026] When the steam sterilization process begins, the operation of the purified water supply device 1 (circulation of purified water) is stopped, and a drainage operation is performed to discharge the purified water in the system to the outside. Specifically, the operation of the heat exchanger 22 is stopped, and if purified water was used at the use point 3 immediately before, the on-off valves V1 and V2 of the respective water supply lines L1 and L2 are closed. Then, the on-off valve (not shown) of the purified water supply line L3 is closed to stop the supply of purified water to tank 2, the on-off valve V11 of the ambient water reflux line L12 and the on-off valve V21 of the low-temperature water reflux line L22 are closed, and the on-off valve V12 of the ambient water discharge line L13 and the on-off valve V22 of the low-temperature water discharge line L23 are opened. As a result, the purified water stored in tank 2 is discharged to the outside from the ambient water circulation line L10 through the ambient water discharge line L13 by the operation of pumps 11 and 21, and similarly from the low-temperature water circulation line L20 through the low-temperature water discharge line L23. Subsequently, when the water level in tank 2 drops to a certain level, pumps 11 and 21 stop operating, clean air is introduced into tank 2, and the pressure from this air pushes out the purified water in each circulation line L10 and L20, which is then discharged to the outside.

[0027] When the purified water in the system is discharged to the outside, the on-off valve V11 of the ambient water reflux line L12 and the on-off valve V21 of the low-temperature water reflux line L22 are opened, and at the same time, the on-off valve V3 of the steam introduction line L4 is opened. In this way, steam is introduced into each circulation line L10 and L20 through tank 2, and the system of the purified water supply device 1 is sterilized. The steam introduced at this time is at a temperature and pressure that can properly sterilize the system. For example, to introduce steam at 121°C or higher, a gauge pressure of about 0.11 MPa (absolute pressure of 0.21 MPa) is sufficient. Furthermore, when introducing steam at 121°C or higher, if the length of the piping to be steam-sterilized is long, if the tank 2 to be steam-sterilized is large, if there are many pieces of equipment to be steam-sterilized, if there are many pipes branching from each circulation line L10 and L20, or if it is necessary to reliably supply steam to locations far from the steam supply source, the gauge pressure should be adjusted to 0.15 to 0.19 MPa. On the other hand, since it is difficult to maintain system pressure when the on-off valves V21 and V22 are open, perforated valves or grooved valves may be installed on the secondary side of the on-off valves V21 and V22 as needed to discharge only steam condensate and maintain system pressure.

[0028] After a certain period of time, the on-off valve V3 of the steam introduction line L4 is closed, and the introduction of steam is stopped. Once the steam sterilization process is complete, an on-off valve (not shown) of the purified water supply line L3 is opened, and the supply of purified water to tank 2 begins, and the circulation of purified water is restarted in the ambient water supply unit 10 and the low-temperature water supply unit 20, respectively. Specifically, in the ambient water supply unit 10, the on-off valve V12 of the ambient water discharge line L13 is closed, and the ambient water pump 11 is activated, causing the purified water in tank 2 to be returned to tank 2 from the ambient water supply line L11 through the ambient water return line L12. In this way, the circulation of purified water (ambient water) along the ambient water circulation line L10 is restarted. Meanwhile, in the low-temperature water supply unit 20, an air venting operation is performed to discharge air from the low-temperature water circulation line L20 to the outside, and then the circulation of purified water is restarted. Specifically, when the on-off valve V21 of the low-temperature water recirculation line L22 is closed and the low-temperature water pump 21 is activated, the purified water in tank 2 flows from the low-temperature water supply line L21 to the low-temperature water recirculation line L22, and then is discharged to the outside through the low-temperature water discharge line L23 without recirculating back to the low-temperature water supply line L21. This discharge of purified water causes the air that filled the low-temperature water circulation line L20 after the steam sterilization process to be discharged to the outside along with the purified water. Subsequently, the on-off valve V21 of the low-temperature water recirculation line L22 is opened and the on-off valve V22 of the low-temperature water discharge line L23 is closed, and the purified water flowing through the low-temperature water recirculation line L22 is recirculated back to the low-temperature water supply line 21, so that the purified water circulates along the low-temperature water circulation line L20.

[0029] However, if the air in the low-temperature water circulation line L20 is not completely removed at this time, that air may be returned to the low-temperature water pump 21, potentially causing cavitation and damaging the low-temperature water pump 21. Also, if the circulation of purified water is restarted and the heat exchanger 22 is operated while the air in the low-temperature water circulation line L20 is not completely removed, it will take a considerable amount of time for the temperature of the purified water (low-temperature water) to stabilize, resulting in the consumption of unnecessary energy and refrigerant.

[0030] Therefore, it is preferable to continue draining the purified water at this time until it is confirmed that all the air in the low-temperature water circulation line L20 has been removed, that is, until it is confirmed that the inside of the low-temperature water reflux line L22 on the downstream side of the low-temperature water circulation line L20 has been filled with purified water. This allows for efficient cooling of the purified water by the subsequent operation of the heat exchanger 22, and shortens the time (startup time) until the temperature of the purified water (low-temperature water) stabilizes. Whether or not the inside of the low-temperature water reflux line L22 has been filled with purified water can be determined, for example, by whether or not the pressure or flow rate of the purified water flowing through the low-temperature water reflux line L22 has reached a steady state, specifically by whether or not a predetermined time has elapsed since the detected value of the pressure sensor 24 or the flow rate sensor 26 reached a predetermined value or higher. Note that the means for detecting fullness of the low-temperature water reflux line L22 is not limited to the pressure sensor 24 or the flow rate sensor 26, but a temperature sensor 25 may also be used. That is, whether or not the inside of the low-temperature water reflux line L22 has been filled with purified water can be determined from the temperature change of the purified water detected by the temperature sensor 25.

[0031] Thus, once it is confirmed that the inside of the low-temperature water circulation line L20 is filled with purified water, the air purging operation of the low-temperature water circulation line L20 ends, and the system switches to circulation operation as described above. Then, the heat exchanger 22 starts to operate and the cooling of the purified water begins, and once the temperature of the circulating purified water (low-temperature water) stabilizes, the circulation operation of the low-temperature water along the low-temperature water circulation line L20 resumes, which means that the normal operation of the purified water supply device 1 resumes.

[0032] Furthermore, if piping constraints such as preventing the accumulation of purified water allow, after the steam sterilization process is completed, the low-temperature water supply unit 20 may, instead of discharging the purified water flowing through the low-temperature water reflux line L22 to the outside, return it to the tank 2 to remove air from the low-temperature water circulation line L20.

[0033] In the embodiments described above, the case of supplying two types of purified water, room temperature and a lower temperature, to the point of use was used as an example. However, the present invention is not limited to this and can also be applied to cases where two types of purified water, room temperature and a higher temperature, are supplied to the point of use. That is, the liquid supply device of the present invention may have a high-temperature water supply unit instead of a low-temperature water supply unit, which has a heat exchanger equipped with a heating mechanism and heats the circulating purified water to a temperature higher than the temperature of the purified water in the tank (room temperature) before supplying it to the point of use. In this case as well, the high-temperature water supply unit can operate in a circulating manner that circulates high-temperature purified water without going through a tank, with a configuration similar to that of the low-temperature water supply unit. [Explanation of Symbols]

[0034] 1 Purified water supply device (liquid supply device) 2 tanks 3 Use Points 4. Control Unit (Control Means) 10 Room temperature water supply section 11. Room temperature water pump 12. Ultraviolet Oxidizer 20 Low temperature water supply section 21 Low-temperature water pump 22 Heat exchanger 23. Ultraviolet Oxidizer 24. Pressure sensor (flow detection means, full water level detection means) 25. Temperature sensor (water level detection means) 26 Flow sensor (flow detection means, full water level detection means) L1, L2 water supply lines L3 Steam introduction line (steam introduction means) L10 Room temperature water circulation line L11 Room temperature water supply line L12 Room temperature water recirculation line L13 Room temperature water discharge line L20 Low-temperature water circulation line L21 Low-Temperature Water Supply Line L22 Low temperature water reflux line L23 Low-temperature water discharge line V1~V3, V11, V12 Shut-off valves V21, V22 On / Off Valves (Flow Path Switching Mechanism)

Claims

1. A tank for storing liquid, A supply line that supplies liquid from the tank to the point of use, A pump provided in the supply line, A heat exchanger provided in the supply line downstream of the pump, which cools or heats the liquid supplied to the use point to a temperature different from that of the liquid in the tank, A recirculation line that recirculates the liquid supplied to the use point through the supply line that was not used at the use point back to the supply line upstream of the pump, A discharge line is connected to the recirculation line at a position close to the downstream end of the recirculation line and discharges the liquid in the supply line and the recirculation line to the outside, Another supply line that supplies liquid from the tank to the point of use, Another pump installed in the aforementioned other supply line, A liquid supply device having another recirculation line for recirculating to the tank any liquid supplied to the use point through the other supply line that was not used at the use point.

2. The liquid supply device according to claim 1, having a flow path switching means that can switch between a first state in which the recirculation line and the supply line are connected in order to perform a circulation operation in which the liquid flowing in the recirculation line is recirculated to the supply line, and a second state in which the recirculation line and the discharge line are connected in order to perform a drainage operation in which the liquid in the supply line and the recirculation line is discharged to the outside from the discharge line, or, after the drainage operation has been performed, to perform an air venting operation in which liquid is supplied from the supply line to the recirculation line and air in the supply line and the recirculation line is discharged to the outside from the discharge line.

3. In the circulation operation described above, the liquid in the tank is supplied to the supply line by the pressure difference between the pressure in the tank and the pressure in the supply line, or by the suction pressure of the pump, and is combined with the liquid being returned from the return line, as described in claim 2.

4. The liquid supply device according to claim 2 or 3, further comprising a control means for switching the flow path switching means from the second state to the first state when it is detected that the inside of the return line is filled with liquid during the air venting operation.

5. The liquid supply apparatus according to claim 4, wherein the control means activates the heat exchanger to start the cooling or heating after switching the flow path switching means from the second state to the first state.

6. The liquid supply device according to claim 4, comprising a flow sensor, a pressure sensor, or a temperature sensor, and having a full-water detection means for detecting whether or not the inside of the recirculation line is filled with liquid.

7. A flow rate detection means for detecting the flow rate of the liquid flowing through the aforementioned return line, It includes a flow rate adjustment means for adjusting the flow rate of the liquid flowing through the aforementioned reflux line, The liquid supply device according to claim 4, wherein the control means controls the flow rate adjustment means so that the flow rate of the liquid flowing through the recirculation line remains constant based on the flow rate detected by the flow rate detection means during the circulation operation.

8. A liquid supply device according to any one of claims 1 to 3, comprising a heat exchanger provided in the supply line or the reflux line, which heats the liquid flowing through the supply line or the reflux line to a predetermined temperature or higher and generates hot water for sterilizing the supply line and the reflux line.

9. A liquid supply apparatus according to any one of claims 1 to 3, further comprising a steam introduction means for introducing steam into the supply line and the reflux line through the tank in order to perform sterilization of the tank, the supply line and the reflux line.

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