Cooling tower

Abstract

This cooling tower allows for adjustment of the water level in the lower tank by adjusting the overflow pipe, enabling efficient operation such as water conservation by setting an appropriate water level according to the operating conditions. [Solution] An overflow pipe 80 is provided that can discharge water from the lower tank as an overflow from one end of the pipe which has an opening. The movable part 81 of the overflow pipe 80 is made to be able to move back and forth relative to the fixed part 82, so that the opening position can be adjusted vertically. This allows the water level at which water overflows into the overflow pipe 80 from the lower tank 50 to be adjusted. As a result, the overflow water level of the lower tank 50 can be set based on the operating state of the cooling tower and the conditions around the cooling tower, allowing the cooling tower to be operated appropriately. Furthermore, water conservation can be achieved by adjusting the water level of the lower tank 50 to a range that does not cause problems, allowing the cooling tower to be operated more efficiently.

Description

Technical Field

[0001] The present invention relates to a cooling tower that cools a liquid-phase heat medium for circulation by exchanging heat with air in a heat exchange section, and particularly relates to a cross-flow type cooling tower.

Background Art

[0002] Generally, in a cooling tower installed outdoors for the purpose of cooling a liquid-phase heat medium such as water that is circulated in a factory or air conditioning equipment, in the heat exchange section inside the cooling tower, air (outdoor air) taken in from the outside is directly or indirectly heat-exchanged with the heat medium as the fan (blower) operates, and a cooling mechanism is provided.

[0003] Among these, the cross-flow type cooling tower is a device that sprinkles circulating water, which is a heat medium, from above onto a filling material with a laminated structure housed in a rectangular tower body, introduces outdoor air from the side, and performs heat exchange between the orthogonal circulating water and outdoor air, and is widely used. As an example of such a conventional cross-flow type cooling tower, there is one disclosed in Japanese Patent Laid-Open No. 6-307795.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A conventional cross-flow type cooling tower has the configuration shown in the above patent document. While water circulates between the cooling tower and a refrigerator or the like, water passing through a heat exchange section such as a filling material in the cooling tower is recovered and temporarily stored in a lower water tank before being newly sent to a device that uses the water of the refrigerator or the like.

[0006] In order to prevent emergencies such as water overflowing from the lower tank if the water level in the lower tank increases for any reason and exceeds the appropriate level, an overflow pipe is generally installed to discharge the excess water outside the lower tank.

[0007] The overflow pipe is a pipe erected at the bottom of the lower tank, with its upper end open and located inside the lower tank, while the lower part of the pipe is connected to the outside of the lower tank, allowing water that flows into the lower tank through the opening at the upper end to be drained to the outside of the lower tank.

[0008] In structures equipped with overflow pipes, when the water level of the circulating water in the lower tank reaches the overflow level, that is, a certain height at the opening of the overflow pipe, water overflows into the opening of the overflow pipe, allowing for drainage. Adjusting this overflow level after the installation and commencement of operation of the cooling tower required methods such as replacing the overflow pipe with one of a different height corresponding to the desired water level, or cutting the overflow pipe to lower the water level. These methods were time-consuming, costly, and not easily carried out.

[0009] On the other hand, in the case of a multi-cell type cooling tower, which has a structure in which multiple cooling tower cells capable of operating independently are connected, each cell is usually set to the same configuration, so the opening height of the overflow pipe to the lower water tank is inherently the same. However, if there are differences in height between the installation surfaces of each cell, or if there are individual differences due to dimensional tolerances of parts or assembly accuracy, the opening height of the overflow pipe will differ for each connected cell.

[0010] On the other hand, since the lower tanks of each cell are interconnected and the water level in the lower tanks is the same, if the opening height of the overflow pipes differs, the timing of reaching the overflow water level in the lower tanks of each cell will differ. Furthermore, even in this situation, it is difficult to adjust the overflow water level by changing the opening height of the overflow pipes, so the system is forced to operate as is.

[0011] As a result, the timing of overflow in each cell differed, leading to problems where drainage due to overflow did not proceed as initially expected. Furthermore, when blowdown was performed by draining through the overflow pipe, it was difficult to achieve uniform blowdown in each cell, and the exchange of circulating water did not proceed evenly in each cell. This resulted in variations in the quality of the circulating water in each cell, negatively impacting cooling efficiency and water flow in the lower tank.

[0012] The present invention was made to solve the aforementioned problems, and aims to provide a cooling tower that allows for adjustment of the water level in the lower tank by adjusting the overflow pipe, thereby enabling efficient operation such as water conservation by setting an appropriate water level according to the operating conditions. [Means for solving the problem]

[0013] The cooling tower disclosed in the present invention is a DC-AC type cooling tower having at least a lower water tank for recovering water that has flowed down from a heat exchange section within the cooling tower body, and is equipped with an overflow pipe erected at the bottom of the lower water tank, wherein one end of the pipe with an opening is located inside the lower water tank and the other end of the pipe is connected to the outside of the lower water tank, and the position of the opening can be adjusted in the vertical direction by connecting a movable part, which is part of the upper section including the opening, to a fixed part that is the remaining part so as to be able to move upward and backward.

[0014] As described above, according to the disclosure of the present invention, an overflow pipe is provided that can discharge water from the lower tank as an overflow from one end of the pipe having an opening, and the movable part of this overflow pipe is made to be able to move back and forth relative to the fixed part, so that the opening position can be adjusted vertically, and the water level at which water overflows into the overflow pipe in the lower tank can be adjusted, so that the overflow water level of the lower tank can be set based on the operating state of the cooling tower and the conditions around the cooling tower, so that the cooling tower can be operated appropriately, and water conservation can be achieved by adjusting the water level of the lower tank to a range that does not cause problems, thereby enabling more efficient operation of the cooling tower.

[0015] Furthermore, even if the cooling tower has a multi-cell structure with multiple cooling tower cells, and the initial height of the overflow pipe differs in each cooling tower cell, adjusting the opening height of the overflow pipe will ensure a uniform overflow state in each cooling tower cell. This allows for rapid drainage, and when applied to blowdown drainage, it enables uniform drainage in each cooling tower cell, reducing the concentration of substances other than water in the water and improving the water quality in the lower tank without bias.

[0016] Furthermore, the cooling tower disclosed in the present invention may optionally include an inspection walkway installed in the vicinity of the lower water tank, straddling the lower water tank, in a space within the cooling tower body where there is no heat exchange section, and the overflow pipe is arranged so that at least the opening is located below the inspection walkway.

[0017] As described above, according to the disclosure of the present invention, by positioning the opening of the overflow pipe below the inspection walkway that is erected to straddle the lower water tank, the inspection walkway prevents water flowing down from the heat exchange section or water droplets falling from other parts of the tower body from entering the opening of the overflow pipe. This prevents water other than the overflow portion of water that has accumulated in the lower water tank from entering the overflow pipe, thereby preventing water that should be circulated from being mistakenly drained to the outside, reducing the amount of water that needs to be replenished, and thus saving water.

[0018] Furthermore, the cooling tower disclosed in the present invention may be provided with an operating section that allows the overflow pipe to adjust the vertical position of the movable part in conjunction with a predetermined movement of the other part, and the operating section is positioned within reach of a worker from above the inspection walkway.

[0019] As described above, according to the disclosure of the present invention, the overflow pipe is provided with an operating part for adjusting the position of the opening in the vertical direction, and this operating part is located within reach of a worker from above the inspection walkway, so that it can be operated by a worker from above the inspection walkway. As a result, the water level at which water in the lower water tank is discharged from the overflow pipe can be easily adjusted by a worker operating the operating part from above the inspection walkway, and the position adjustment work can be performed more efficiently.

[0020] Furthermore, the cooling tower disclosed in the present invention may optionally have a door portion in the inspection walkway that can be opened and closed within a predetermined range located above the opening in the overflow pipe, and the overflow pipe is such that the opening can be adjusted from above through a hole or notch in the inspection walkway created by opening the door portion.

[0021] As described above, according to the disclosure of the present invention, a door that can be opened and closed is provided at a location above the opening of the overflow pipe in the inspection walkway, and when adjusting the position of the overflow pipe opening in the vertical direction, the worker can adjust the position through the hole or notch created by opening the door. This allows the worker to directly see the opening on the inspection walkway side and adjust the position by approaching it from the upper side of the inspection walkway at the shortest distance, eliminating the need for the worker on the upper side of the inspection walkway to reach in from the side of the inspection walkway to perform operations related to adjusting the position of the opening. As a result, the worker can perform the work more easily from the upper side of the inspection walkway, and the work efficiency can be improved.

[0022] Furthermore, the cooling tower disclosed in the present invention is configured such that, if necessary, the inspection walkway is movably or tiltably arranged relative to the lower water tank between at least a position above the opening in the overflow pipe and a position offset from that position to expose the opening.

[0023] According to the disclosure of the present invention as described above, when the inspection walkway is provided so as to be movable or tiltable with respect to the lower water tank and the position of the opening of the overflow pipe is adjusted in the vertical direction, the inspection walkway is shifted from a state where it is located above the opening of the overflow pipe, and the opening is shifted to a state where it is exposed without being covered from above by the inspection walkway, and then the position adjustment with respect to the opening is performed. As a result, an operator can perform the position adjustment work by approaching the opening from above at the shortest distance while directly visualizing the opening, and the operator on the upper side of the inspection walkway does not have to reach out from the side of the inspection walkway to perform an operation related to the position adjustment of the opening. Thus, the operator can more easily perform the work from the inspection walkway side, and the work efficiency can be improved.

[0024] Further, the cooling tower according to the disclosure of the present invention optionally includes a drainage guide portion formed of a substantially cylindrical body surrounding the outside of the overflow pipe and disposed in a standing state in the lower water tank. The drainage guide portion has a gap with the inner overflow pipe, and the upper end portion is disposed higher than the upper end of the overflow pipe. One or a plurality of passage portions are provided in the vicinity of the bottom surface of the lower water tank to allow communication between the inside and the outside of the cylinder of the drainage guide portion.

[0025] According to the disclosure of the present invention as described above, a drain guide part is arranged outside the overflow pipe in the lower water tank. When the water level in the lower water tank overflows beyond the opening at the upper end of the overflow pipe, the water reaches the opening of the overflow pipe through the passage part at the lower part of the drain guide part and the gap between the drain guide part and the overflow pipe. When foreign matters such as scale accumulate and collect at the bottom of the lower water tank, a part of the foreign matters is guided into the drain guide part along with the water flowing into the passage part at the lower part of the drain guide part. Further, the foreign matters are lifted along with the water flowing upward from the bottom to the top between the drain guide part and the overflow pipe and reach the opening, and the foreign matters are discharged to the outside through the overflow pipe together with the water. Thus, the foreign matters deposited and fallen in the water and accumulated in the lower water tank can be discharged out of the tank every time there is an overflow opportunity, and the labor for maintenance work such as removing the foreign matters accumulated in the lower water tank can be reduced. Also, the amount of foreign matters adhering to the strainer that filters the water flowing from the lower water tank to the circulation path along with the discharged water due to the overflow can be reduced, and the frequency of maintenance such as cleaning and replacement of the strainer can also be decreased, and the maintenance cost related to the entire cooling tower can be reduced.

[0026] Furthermore, the water discharged from the overflow pipe once passes through the passage part of the drain guide part. Since the water near the bottom surface of the lower water tank can be discharged by overflow, when blowing down, the clean makeup water supplied to the lower water tank can discharge the water at a position where it is difficult to reach immediately by overflow, reducing the proportion of the makeup water discharged immediately after water supply, effectively eliminating the concentration state of the water in the lower water tank, and realizing water conservation by reducing the water supply amount.

[0027] Also, according to the disclosure of the present invention, the cooling tower may, if necessary, have the drain guide part provided with an opening at the upper end part, and a part of the upper part including the opening is connected to the remaining other part so as to be able to move forward and backward upward, and the opening can be adjusted in position in the vertical direction.

[0028] As described above, according to the disclosure of the present invention, a portion of the drainage guide section, including the opening at its upper end, which is disposed on the outside of the overflow pipe, is made movable relative to other parts, and the position of the opening at the upper end of this drainage guide section can be adjusted vertically. In some cases, the position of the opening can be lowered so that water in the lower tank flows inward from the opening at the upper end of the drainage guide section. This sets the position of the opening of the drainage guide section close to the upper end opening of the overflow pipe. If the water level in the lower tank during overflow reaches above the opening at the upper end of the drainage guide section, water will flow inward from the opening at the upper end of the drainage guide section and proceed to the opening of the overflow pipe, where it will be discharged outside the tank. Since the water does not pass through the passage section at the bottom of the drainage guide section or the gap between the drainage guide section and the overflow pipe, the water in the lower tank can be discharged to the outside through the overflow pipe more quickly, and the return from the overflow state to the normal state can be expelled in a shorter time. [Brief explanation of the drawing]

[0029] [Figure 1] This is a partially cutaway front view of a cooling tower according to the first embodiment of the present invention. [Figure 2] This is a plan view of the lower water tank in a cooling tower according to the first embodiment of the present invention. [Figure 3] This is an explanatory diagram illustrating the arrangement of the overflow pipe within the lower water tank in a cooling tower according to the first embodiment of the present invention. [Figure 4] This is an enlarged view of the overflow pipe in a cooling tower according to the first embodiment of the present invention. [Figure 5] This is an explanatory diagram illustrating the arrangement of other overflow pipes within the lower water tank in a cooling tower according to the first embodiment of the present invention. [Figure 6] This is an explanatory diagram illustrating the positional adjustment state of another overflow pipe in a cooling tower according to the first embodiment of the present invention. [Figure 7] This diagram illustrates the tilting state of another inspection walkway in a cooling tower according to the first embodiment of the present invention. [Figure 8] This is an explanatory diagram illustrating the arrangement of the overflow pipe and drainage guide section within the lower water tank in a cooling tower according to a second embodiment of the present invention. [Figure 9] This is an enlarged view of the overflow pipe and drainage guide section in a cooling tower according to a second embodiment of the present invention. [Figure 10] This is an explanatory diagram of the water flow around the overflow pipe during overflow in a cooling tower according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0030] (First embodiment of the present invention) Hereinafter, a cooling tower according to the first embodiment of the present invention will be described based on Figures 1 to 4. In this embodiment, we will describe an example of application to an open-type cooling tower in which circulating water to be cooled is sprayed onto the packing material inside the cooling tower, while outside air is circulated through the packing material by induced airflow from a blower, thereby allowing heat exchange between the air and circulating water in the packing material.

[0031] As shown in the figures above, the cooling tower 1 according to this embodiment comprises a tower body 10 through which circulating water and outside air pass inside, a packing material 20 that exchanges heat between circulating water and air as a heat exchange section within the tower body 10, an upper water tank 30 disposed above the packing material 20 to receive circulating water and spray this circulating water onto each part of the packing material 20, a lower water tank 50 disposed below the packing material 20 to collect the circulating water that has passed through the packing material 20, a water distribution pipe 60 that takes the circulating water from the lower water tank 50, sends it back to the upper water tank 30 after passing through a predetermined circulation pipe 95, and a blower 70 disposed above the center of the lower water tank 50 to pass outside air between each packing material sheet 21 of the packing material 20 by induced airflow.

[0032] The cooling tower 1 according to this embodiment is an open-type cooling tower of the cross-flow type, in which two sets of packing material 20 are arranged opposite each other with a central section containing a blower 70 inside the tower body 10, and external air is drawn in from the side to each packing material 20 by induced airflow from the blower 70, and heat exchange is performed between this air and the circulating water.

[0033] The tower body 10 is shaped to surround a tower interior space with a rectangular cross-section. Inside, two sets of packing material 20 are arranged opposite each other with a central ventilation space in between. Air intake ports 11 are provided on two sides facing each set of packing material 20, and an exhaust port 12 is provided at the top center to discharge the air that has undergone heat exchange with the packing material 20.

[0034] This tower structure 10 is configured such that a plate-shaped inspection walkway 15 is erected in the vicinity of the lower water tank 50, in the space above the lower water tank 50 where there is no internal filling material 20, and the walkway straddles the lower water tank 50.

[0035] The aforementioned filler material 20 is formed by integrating a large number of roughly plate-shaped filler sheets 21 in a stacked state, with the stacking direction being horizontal and the gaps between the filler sheets 21 facing the suction ports 11 on the side of the tower body 10, and is arranged in one or multiple layers stacked vertically within the tower body 10.

[0036] Furthermore, regarding the configuration of each part of the packing material 20 that serves as a heat exchange section, where heat exchange takes place between circulating water flowing down along each packing material sheet 21 and air flowing through the gaps between the packing material sheets 21 in a direction perpendicular to the direction of flow of the circulating water, it is the same as that of a known DC-AC open-type cooling tower packing material, and therefore a detailed explanation is omitted.

[0037] The upper water tank 30 is formed as a shallow box-shaped body with numerous small holes at its bottom and is positioned above each packing material 20 at the top of the tower body 10. The upper water tank 30 is connected to the water distribution pipeline 60 and receives a supply of circulating water. The circulating water supplied to the upper water tank 30 comes out of the lower water tank 50, passes through a circulation pipeline 95 leading to chillers and air conditioning equipment, and then through the water distribution pipeline 60. The upper water tank 30 distributes the circulating water uniformly at a predetermined rate from the numerous holes at its bottom towards each part of the packing material 20 below, thereby spraying water. This water spraying mechanism of the circulating water by the upper water tank 30 is the same as that of known cooling towers, and a detailed explanation is omitted.

[0038] The lower water tank 50 is installed on a water tank reinforcing frame 51 fixed to the lower side of the tower body 10, and receives circulating water flowing down from the packing material 20, temporarily stores it, and then recovers it. The lower water tank 50 is connected to a water supply section (not shown) for supplying makeup water when the circulating water level decreases, and to a circulation pipeline 95 that allows circulating water to flow in and out of the cooling tower, and is capable of storing a predetermined amount of circulating water.

[0039] A strainer 57 is provided at the outlet of the water flowing into the circulation pipe 95 in the lower water tank 50 to separate foreign matter such as scale deposited in the water, so that only circulating water flows into the circulation pipe 95.

[0040] Furthermore, an overflow pipe 80, formed of a tubular body, is erected at the bottom of the lower tank 50, with one end of the pipe having an opening located inside the tank and the other end of the pipe connected to a drainage pipe outside the tank (not shown). The configuration of each part of this lower water tank 50, excluding the overflow pipe 80 and its surroundings, is the same as that of a known cooling tower, and therefore a detailed explanation is omitted.

[0041] The overflow pipe 80 has a movable portion 81, which is an upper part including the opening, connected to the remaining fixed portion 82 so that it can move upward and backward, thereby allowing the opening to be positioned vertically. The overflow pipe 80 is positioned below the inspection walkway 15, with its opening and other parts located therein.

[0042] The overflow pipe 80 is provided with an operating unit 83 that switches between a state in which the movable part 81 can be adjusted vertically and a state in which it is fixed and immovable, relative to the fixed part 82. The operating unit 83 is located on the overflow pipe 80 within reach of a worker from above the inspection walkway 15. In detail, the movable part 81 and the operating unit 83 of the overflow pipe 80 are located below the part that is closer to the short end of the inspection walkway 15.

[0043] The operating section 83 is screwed into and screwable to the fixed section 82, and its restraint state relative to the movable section 81 can be adjusted. When the operating part 83 is screwed loosely relative to the fixed part 82, the pressing force from the operating part 83 to the part attached to the fixed part 82 that is involved in restraining the movable part 81 (not shown) decreases. Consequently, the restraining force on the movable part 81 based on this pressing force weakens, making it possible to adjust the vertical position of the movable part 81 relative to the fixed part 82. On the other hand, when the operating part 83 is screwed tightly relative to the fixed part 82, the pressing force from the operating part 83 to the above-mentioned part increases, and the restraining force on the movable part 81 based on this pressing force strengthens, resulting in a state where the movable part 81 cannot be moved relative to the fixed part 82. Once the movable part 81 is in a state where its vertical position can be adjusted, the operator moves the movable part 81 by hand to adjust its vertical position.

[0044] The aforementioned water distribution pipeline 60 is installed inside the tower body 10 as a pipeline that supplies circulating water, which has been returned to the cooling tower 1 via the circulation pipeline 95, to the upper water tank 30. The blower 70 is positioned in the upper center of the tower body 10. It introduces outside air horizontally to each packing material 20 through the intake port 11 via induced airflow through the ventilation space below it. The air that has passed through the packing material 20 and reached the ventilation space is then sent further upward and discharged outside the tower body 10. The configuration for air ventilation by this blower 70 is the same as that of known cooling towers, and a detailed explanation is omitted.

[0045] Next, the operating state of the cooling tower based on the above configuration will be described. The circulating water flowing through the circulation pipeline 95, which includes the cooling tower 1, receives heat from refrigerators, air conditioning equipment, etc., located along the circulation pipeline 95, as in known cooling towers, and reaches the cooling tower 1 under normal operating conditions. The circulating water that returns to the cooling tower 1 first enters the water distribution pipeline 60 inside the tower body 10 and proceeds along the pipeline toward the upper water tank 30.

[0046] The circulating water introduced into the upper tank 30 via the water distribution pipeline 60 passes through each hole at the bottom of the upper tank 30 in a predetermined time, and is distributed and dripped to each part of the packing material 20 below, reaching the packing material 20. In the packing material 20, outside air drawn into the tower body 10 from the intake port 11 by induced ventilation by the blower 70 is introduced laterally into the gaps between each packing material sheet 21 that make up the packing material 20.

[0047] The circulating water that reaches the packing material 20 proceeds into each gap between the packing material sheets 21 that make up the packing material 20, and flows down along the packing material sheets 21, coming into contact with the outside air flowing laterally through the same gaps. The circulating water is cooled mainly by heat transfer (sensible heat) due to the temperature difference between the air and the circulating water, and by the heat of vaporization (latent heat) of the circulating water, while the heat exchange conversely raises the temperature of the air.

[0048] The circulating water is cooled through heat exchange with the air in the packing material 20, then exits the packing material 20 and reaches the lower water tank 50 where it is collected. The circulating water accumulated in the lower water tank 50 passes through the strainer 57 at the outlet of the lower water tank and then re-enters the circulation pipeline 95. As the circulating water flows through the circulation pipeline 95, it receives heat from the chiller, air conditioning equipment, etc., before returning to the cooling tower 1 and entering the water distribution pipeline 60, after which the above process is repeated.

[0049] Meanwhile, the air, whose temperature has risen through heat exchange with the circulating water, is drawn by the blower 70 to pass through the gaps between the packing material sheets 21 that make up the packing material 20, exit the packing material 20, and proceed to the ventilation space in the center of the inside of the tower body 10. The air that reaches the ventilation space is discharged outside the cooling tower by the blower 70, and the discharged air diffuses into the outside air.

[0050] In the lower tank 50, if the amount of water in the lower tank 50 becomes excessive for any reason and the water level in the lower tank 50 rises, the overflow pipe 80 will cause the excess water to overflow and discharge it from the overflow pipe 80 to the drainage pipe outside the tank (not shown in the diagram), thereby maintaining the water level within an appropriate range.

[0051] The opening in the overflow pipe 80 into which water enters is located below the inspection walkway 15, making it difficult for water that has passed through the packing material 20, or water that flows down from the packing material 20 and reaches the part of the lower water tank 50 located below the packing material 20, to flow towards the center of the lower water tank. Therefore, the overflow pipe 80 hardly allows any water other than the excess water that has accumulated in the lower water tank 50 to enter. In this way, by making it difficult for water that should be circulated to be mistakenly drained to the outside, the amount of water that needs to be replenished can be reduced, thus saving water.

[0052] As the cooling tower continues to be used, the circulating water will become concentrated, so it is necessary to blow down the concentrated circulating water at the appropriate time. When blowing down the circulating water, a valve located in the water supply section (not shown) of the lower tank 50 is temporarily opened, and clean makeup water is supplied to the lower tank 50. As this makeup water is supplied, the water level in the lower tank 50 rises, causing some of the concentrated circulating water to reach the drainage pipe outside the lower tank 50 through the overflow pipe 80 and be discharged to the outside through this drainage pipe.

[0053] In this blowdown system, highly concentrated circulating water is discharged from the overflow pipe 80, while clean replenishment water corresponding to the discharged volume is supplied separately to the lower tank 50, thereby mitigating the concentration of the circulating water.

[0054] As described above, in the cooling tower according to this embodiment, an overflow pipe 80 is provided that can discharge water from the lower water tank 50 to the outside of the tank as an overflow from one of the open pipe ends. Furthermore, a part of this overflow pipe 80 is made movable relative to the other part, allowing the opening position of one of the pipe ends to be adjusted vertically. This allows the water level at which water overflows into the overflow pipe 80 from the lower water tank 50 to be adjusted. Therefore, the overflow water level of the lower water tank 50 can be set based on the operating state of the cooling tower and the conditions around the cooling tower, enabling the cooling tower to be operated appropriately. In addition, water conservation can be achieved by adjusting the water level of the lower water tank 50 to a level that does not cause problems, thereby enabling the cooling tower to be operated more efficiently.

[0055] In the cooling tower according to the above embodiment, circulating water is sprayed onto the packing material 20 that forms the heat exchange section to exchange heat with air, and an overflow pipe 80 with an adjustable opening position is provided in the lower water tank 50 of the open-type cooling tower. However, the configuration is not limited to this, and it is also possible to use a heat exchanger in which the flow path of the heat transfer medium such as circulating water or brine and the flow path of the air to be heat exchanged are completely separated, and water is sprayed onto this heat exchanger to perform heat exchange between the air and the heat transfer medium, including the latent heat of vaporization, and an overflow pipe with an adjustable opening position is provided in the lower water tank of the closed-type cooling tower.

[0056] In this case, the water stored in the lower tank is only for watering the heat exchange section, and although the water level fluctuations and overflow opportunities in the lower tank are less frequent than in the open type, as in the above embodiment, the operation can be stabilized by adjusting the overflow pipe in response to changes in the operating conditions of the cooling tower.

[0057] Furthermore, in the cooling tower according to the above embodiment, the overflow pipe 80 in the lower water tank 50 is configured to be located below the inspection walkway 15 which is arranged inside the tower body 10. However, the configuration is not limited to this, and the overflow pipe can be configured to be located at a place other than below the inspection walkway, as long as it is in a position where water such as circulating water flowing down from the packing material is unlikely to enter the opening of the overflow pipe.

[0058] In this case, when adjusting the height of the overflow pipe according to the set water level for overflow, the inspection walkway does not cover the overflow pipe, making the adjustment work easier and improving work efficiency.

[0059] Furthermore, in the cooling tower according to the above embodiment, the movable part 81 and the operating part 83 of the overflow pipe 80 provided on the lower side of the inspection walkway 15 are positioned below the end in the short direction of the inspection walkway 15, making it easier for workers on the upper side of the inspection walkway 15 to perform position adjustment operations on the overflow pipe 80. However, the configuration is not limited to this, and as shown in Figure 5, the entire overflow pipe 80 can also be provided so that it is located below the central part of the inspection walkway 15.

[0060] However, in this regard, it is desirable to adopt a configuration that allows workers to perform positional adjustment operations on the overflow pipe from above the inspection walkway without any hindrance, in addition to the arrangement of the overflow pipe. For example, in accordance with such an arrangement of the overflow pipe, as shown in Figure 6, a door section 18 that can be opened and closed can be provided in a part of the inspection walkway 15 located above the overflow pipe 80, so that when adjusting the position of the overflow pipe 80, the door section 18 of the inspection walkway 15 can be opened and the worker can approach the overflow pipe 80 from directly above to perform positional adjustment operations.

[0061] In this case, when adjusting the height of the overflow pipe 80 according to the set water level for overflow, opening the door section 18 allows the adjustment work on the overflow pipe 80 to be performed quickly while visually inspecting the overflow pipe 80 from above, regardless of the presence of the inspection walkway 15. Furthermore, since the worker does not have to bypass the inspection walkway 15 to approach the overflow pipe 80 from the side to perform position adjustment operations, the work becomes easier and work efficiency is improved.

[0062] Furthermore, the door section may be located near the center of the short side of the inspection walkway, creating an opening when opened, or it may be located near the short end of the inspection walkway, creating a notch when opened.

[0063] Furthermore, in the cooling tower according to the above embodiment, the overflow pipe 80 is provided below the inspection walkway 15, and the operator is required to access the overflow pipe 80 from the side by bypassing the inspection walkway 15 to perform position adjustment operations. However, the configuration is not limited to this, and the inspection walkway 15 located above the overflow pipe 80 can be shifted by sliding it relative to the lower water tank 50 or by tilting it relative to the lower water tank 50 as shown in Figure 7, so that the upper part of the overflow pipe 80 can be directly viewed and accessed from above, and the operator can perform position adjustment operations on the overflow pipe 80 from above.

[0064] In this case, when adjusting the height of the overflow pipe 80 according to the set water level for overflow, the inspection walkway 15 can be moved so that it does not obstruct the work, and the adjustment work on the overflow pipe 80 can be quickly performed from above while visually inspecting the overflow pipe 80, making the work easier and improving work efficiency.

[0065] Furthermore, although the cooling tower described in the above embodiment is a single-cell type cooling tower equipped with only one set of an operable blower and a packing material as a heat exchange section within the tower body, it is not limited to this, and a cooling tower with a multi-cell structure in which multiple DC-AC type cooling tower cells are connected may also be used.

[0066] In this case, even if the initial height of the overflow pipe differs in each cell, adjusting the opening height of the overflow pipe in each cell will ensure a uniform overflow state in each cell, allowing for rapid drainage. Furthermore, when applied to drainage related to blowdown, uniform drainage is achieved in each cooling tower cell, reducing the concentration of substances other than water in the water and improving the water quality of the lower tank without bias.

[0067] (Second embodiment of the present invention) In the cooling tower according to the first embodiment described above, the overflow pipe 80 erected in the lower water tank 50 is in direct contact with the water in the lower water tank 50, and is configured to discharge water from the lower water tank 50 that is close to the water surface near the opening at its end to the outside when overflow occurs, and no other parts that would affect water discharge are placed around the overflow pipe 80. However, the configuration is not limited to this, and as a second embodiment, as shown in Figures 8 to 10, a substantially cylindrical drain guide section 90 can be provided to surround the overflow pipe 80. In this embodiment, the cooling tower has the same configuration as the first embodiment, except for the overflow pipe 80 and the drainage guide section 90, and therefore a detailed explanation is omitted.

[0068] The overflow pipe 80 has an upper movable portion 81, which includes an opening, connected to the remaining fixed portion 82 so that it can move upward and backward, thereby allowing the opening to be positioned vertically. In detail, the movable part 81 is screw-movably disposed relative to the fixed part 82. As a result, when the movable part 81 is rotated relative to the fixed part 82, the screw-movement of the movable part 81 relative to the fixed part 82 causes the movable part 81 to move vertically as well. This allows for vertical position adjustment of the movable part 81. This overflow pipe 80 is positioned entirely below the inspection walkway 15.

[0069] The drain guide section 90 is formed as a substantially cylindrical body that surrounds the outside of the overflow pipe 80 and is configured to be installed in an upright position in the lower water tank 50. The drain guide section 90 is positioned with a gap between it and the inner overflow pipe 80, and its upper end is positioned higher than the upper end of the overflow pipe 80. In addition, multiple passage sections 91 are provided near the bottom surface of the lower water tank 50, allowing the inside and outside of the drain guide section 90 to pass through. The passage sections 91 are obtained when a notch provided at the lower end of the drain guide section 90 is positioned at the bottom of the lower water tank 50, creating a gap between the edge of the notch and the bottom of the lower water tank 50. This drainage guide section 90 is also positioned entirely below the inspection walkway 15.

[0070] Next, the overflow state of the lower water tank in the cooling tower based on the above configuration will be described. If the amount of water in the lower tank 50 becomes excessive and the water level in the lower tank 50 rises, the overflow pipe 80 will overflow the excess water to maintain the water level within an appropriate range, and the excess water will be discharged from the overflow pipe 80 to the drainage pipe outside the tank (not shown in the diagram).

[0071] In this overflow state, water from the lower tank 50 first flows into the drain guide section 90 through the passage section 91 of the drain guide section 90. The water rises from the bottom of the lower tank 50 through the gap between the drain guide section 90 and the overflow pipe 80 and reaches the upper opening of the overflow pipe 80. The water then flows into the inside of the overflow pipe 80 in an overflowing manner, flows down the inside of the overflow pipe 80 and is discharged outside the tank.

[0072] Meanwhile, during the circulation process of the circulating water, foreign matter such as impurities precipitated in the circulating water from the packing material 20 onward, as well as detached scale, reaches the lower tank 50 and settles and accumulates at the bottom of the lower tank 50. In an overflow state, when water from the lower tank 50 flows into the drainage guide section 90 through the passage section 91 of the drainage guide section 90, any foreign matter such as impurities and scale accumulated at the bottom of the lower tank 50 that is present around the drainage guide section 90 is taken in by the water flow and enters the interior of the drainage guide section 90 from the passage section 91 along with the water. As the water flows upward through the gap between the drain guide section 90 and the overflow pipe 80, the foreign matter also rises through the gap between the drain guide section 90 and the overflow pipe 80.

[0073] Ultimately, the foreign matter flows into the overflow pipe 80 along with the water and is discharged to the outside. In this way, foreign matter such as impurities and scale that have precipitated or fallen off into the water reach the lower tank 50 and accumulate, but are efficiently discharged with each overflow from the lower tank 50, and the amount of foreign matter that accumulates in the lower tank 50 is significantly reduced.

[0074] When blowing down the circulating water, as the water level in the lower tank 50 rises with the supply of makeup water, some of the concentrated circulating water flows into the drainage guide section 90 through the passage section 91, and, as with normal overflow, foreign matter accumulated at the bottom of the lower tank 10 enters the drainage guide section 90 through the passage section 91. The water and foreign matter then rise through the gap between the drainage guide section 90 and the overflow pipe 80, flow into the overflow pipe 80, and are discharged outside the lower tank 50. In this way, blowdown alleviates the concentration of the circulating water and reduces the amount of foreign matter accumulated in the lower tank 50.

[0075] Similar to the first embodiment described above, the opening in the overflow pipe 80 is located below the inspection walkway 15, making it difficult for water that has passed through the packing material 20, or water that flows down from the packing material 20 and reaches the area below the packing material 20 in the lower water tank 50, to flow towards the center of the lower water tank, to enter. Furthermore, the overflow pipe 80 is surrounded by a drainage guide section 90 that is higher than it. As a result, the overflow pipe 80 does not allow any water other than the excess water that has accumulated in the lower water tank 50 to enter. In this way, it is possible to reliably prevent water that should be circulated from being mistakenly drained to the outside, reduce the amount of water that needs to be replenished, and conserve water.

[0076] As described above, in the cooling tower according to this embodiment, a drain guide section 90 is provided on the outside of the overflow pipe 80 in the lower water tank 50. When the water level in the lower water tank 50 overflows and exceeds one end of the upper part of the overflow pipe 80, the water reaches one end of the overflow pipe 80 through the passage section 91 at the bottom of the drain guide section 90 and the gap between the drain guide section 90 and the overflow pipe 80. When foreign matter such as scale accumulates at the bottom of the lower water tank 50, some of the foreign matter is guided into the drain guide section 90 along with the water flowing into the passage section 91 at the bottom of the drain guide section 90. Furthermore, the foreign matter is raised along with the water flowing from bottom to top between the drain guide section 90 and the overflow pipe 80, reaching one end of the pipe, and the foreign matter is discharged to the outside through the overflow pipe 80 along with the water. This allows foreign matter that precipitates in the water, falls off, and accumulates in the lower tank 50 to be discharged outside the tank each time there is an overflow, reducing the effort required for maintenance such as removing foreign matter accumulated in the lower tank 50.

[0077] Furthermore, the amount of foreign matter adhering to the strainer that filters the water flowing from the lower tank 50 to the circulation path is reduced due to the overflow, which also reduces the frequency of maintenance such as cleaning and replacing the strainer, thereby lowering the overall maintenance costs for the cooling tower.

[0078] Furthermore, the water discharged from the overflow pipe 80 passes through the passage 91 of the drain guide section 90, allowing water near the bottom of the lower tank to be discharged by overflow. This means that during blowdown, water in locations that are not immediately reached by the replenishment water supplied to the lower tank 50 is discharged by overflow, reducing the proportion of replenishment water discharged immediately after supply. This efficiently eliminates the concentrated state of water in the lower tank and reduces the amount of water supplied, thus achieving water conservation.

[0079] In the cooling tower according to the above embodiment, the passage portion 91 provided near the bottom surface of the lower water tank of the drainage guide portion 90 is based on a notch provided at the lower end of the drainage guide portion 90. However, it is not limited to this, and a hole can be provided near the lower end of the drainage guide portion and used as the passage portion. Alternatively, the drainage guide portion may be arranged with a gap between it and the bottom of the lower water tank, and the resulting gap can be used as the passage portion.

[0080] Furthermore, in the cooling tower according to the above embodiment, the movable part 81 that requires operation to adjust the position of the overflow pipe 80 is surrounded by the drainage guide part 90, and the configuration allows operation only from above. However, the configuration is not limited to this, and the vertical position adjustment of the overflow pipe may also be made possible from the side. As a mechanism for this, for example, in the overflow pipe, the movable part is connected to the fixed part so as to be able to move upward and backward, while an intermediate rotating part is newly provided that allows the movable part to be adjusted vertically in conjunction with the rotation of the fixed part. The intermediate rotating part is screwed to the movable part and is arranged so as to be screwable relative to it, and is also arranged so as to be rotatable relative to the fixed part. If this intermediate rotating part and the drainage guide part which is rotatably arranged in the lower water tank are connected as a single unit, the vertical position adjustment of the movable part of the overflow pipe can be made by operating the drainage guide part.

[0081] In this case, when adjusting the vertical position of the movable part, rotating the intermediate rotating part together with the drain guide part causes the movable part to move linearly relative to the intermediate rotating part, which is constrained to the fixed part and only capable of rotation, due to the relative screw motion of the rotating intermediate rotating part with respect to the movable part. This makes it possible to adjust the vertical position of the movable part.

[0082] Furthermore, in the cooling tower according to the above embodiment, the drain guide section 90 is formed as a substantially cylindrical body and is fixed in place, and the position of each part, such as the upper end, is always constant. However, the configuration is not limited to this, and for example, a part of the upper part of the drain guide section, including the upper end, may be connected to the remaining parts so as to be able to move upward and backward, thereby allowing the upper end to be adjusted in the vertical direction.

[0083] In this case, the positional relationship between the opening at the upper end of the drain guide section and the upper end opening of the overflow pipe can be changed as needed. This allows the opening at the upper end of the drain guide section to be set close to the upper end opening of the overflow pipe. If the water level in the lower tank during an overflow exceeds the opening at the upper end of the drain guide section, the water exceeding this opening will flow inward through the opening at the upper end of the drain guide section, proceed to one end of the overflow pipe, and be discharged outside the tank. Because the water does not pass through the passage at the bottom of the drain guide section or the gap between the drain guide section and the overflow pipe, the water in the lower tank can be discharged to the outside through the overflow pipe more quickly, allowing for a faster return from an overflow state to a normal state. [Explanation of Symbols]

[0084] 1 cooling tower 10 Tower 11 Inlet 12 Outlet 15 Inspection walkway 18 Door section 20 Filler 21 Filling sheet 30 Upper aquarium 50 Lower tank 51 Aquarium reinforcement frame 57 Strainer 60 Water pipeline 70 Blower 80 Overflow pipe 81 Moving parts 82 Fixed part 83 Operation section 90 Drain guide section 91 Passage section 95 Circulation pipeline

Claims

1. In a DC-AC type cooling tower having at least a lower water tank for recovering water that has flowed down from the heat exchange section within the cooling tower body, The system includes an overflow pipe, which is erected at the bottom of the lower tank and is formed of a tubular body, with one end having an opening located inside the lower tank and the other end leading outside the lower tank. The overflow pipe is configured such that a movable portion, which includes the opening, is connected to the remaining fixed portion so that it can move upward and backward, thereby allowing the position of the opening to be adjusted vertically. A distinctive feature is the cooling tower.

2. In the cooling tower described in claim 1, In the space within the cooling tower body where there is no heat exchange section, an inspection walkway is provided near the lower water tank, positioned to straddle the lower water tank. The overflow pipe is installed so that at least the opening is located below the inspection walkway. A distinctive feature is the cooling tower.

3. In the cooling tower described in claim 2, The overflow pipe is provided with an operating unit that allows the movable part to be adjusted vertically in conjunction with a predetermined movement relative to the other part, and the operating unit is positioned within reach of the worker from above the inspection walkway. A distinctive feature is the cooling tower.

4. In the cooling tower described in claim 2, The inspection walkway has a door section that can be opened and closed within a predetermined range located above the opening in the overflow pipe, The overflow pipe is designed so that the opening can be adjusted from above through a hole or notch in the inspection walkway created by opening the door. A distinctive feature is the cooling tower.

5. In the cooling tower described in claim 2, The inspection walkway is arranged to be movable or tiltable relative to the lower water tank, at least between a position above the opening in the overflow pipe and a position offset from that position that exposes the opening. A distinctive feature is the cooling tower.

6. In the cooling tower according to any one of claims 1 to 5, It is formed as a substantially cylindrical body surrounding the outside of the overflow pipe and includes a drainage guide section that is installed in an upright position in the lower water tank. The drain guide section is positioned with a gap between it and the inner overflow pipe, and its upper end is positioned higher than the upper end of the overflow pipe. Furthermore, one or more passages are provided near the bottom surface of the lower water tank, allowing the inside and outside of the drain guide section to connect. A distinctive feature is the cooling tower.

7. In the cooling tower described in claim 6, The drainage guide section is provided with an opening at its upper end, and a portion of the upper part including the opening is connected to the remaining portion so as to be able to move upward and backward, thereby allowing the opening to be positioned vertically. A distinctive feature is the cooling tower.

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