Circulation Pump Unit

Abstract

To enable a degree of deterioration of a sealing section of a circulation pump unit to be determined.SOLUTION: A circulation pump unit (3) comprises: a circulation pump (1a and 1b) which circulates hot water; suction piping which is connected to a suction side of the circulation pump; a leaked water pan (12) which has discharge piping connected to a discharge side of the circulation pump in a casing and is arranged below the circulation pump to receive leaked water therefrom; and water level detection means (21e) which is arranged in a storage tank (21) storing the leaked water received with the leaked water pan and detects a predetermined water level in the storage tank. When a predetermined amount or more of the leaked water is accumulated in the storage tank, the circulation pump unit discharges the leaked water at once using a siphon phenomenon. The circulation pump unit measures and stores duration of a water level equal to or higher than a predetermined water level since detection of the predetermined water level with the water level detection means and determines a degree of deterioration of a sealing section of the circulation pump on the basis of a temporal change in the duration.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a circulation pump unit of an instant hot water circulation system that circulates high-temperature hot water to instantly supply hot water from a hot water tap or the like. [Background technology]

[0002] Conventionally, in facilities equipped with multiple hot water taps, such as hotels and hospitals, instant hot water circulation systems have been used that are configured to circulate high-temperature hot water heated by a hot water supply device constantly or intermittently at a predetermined cycle, thereby enabling instant hot water to be supplied from any hot water tap. In such instant hot water circulation systems, a circulation pump unit equipped with a mechanical seal type circulation pump that can handle the required large flow rate and high discharge pressure is used.

[0003] When the cumulative operating time of a mechanical seal type circulation pump exceeds a certain period of time, the mechanical seal wears out and water leakage is likely to occur. Therefore, the circulation pump unit is configured to detect and notify the leakage of the circulation pump. For example, the leakage water received by the leakage pan is stored in a storage tank, and when the water level in the storage tank reaches a predetermined water level, the leakage is notified by lighting a lamp or sounding an alarm.

[0004] The applicant of this application has proposed a technology in which a drain outlet is provided in the storage tank, to which a drain hose (drain pipe) is connected for draining water to the outside, and when a predetermined amount of water accumulates in the storage tank, the siphon effect of the bent U-shaped pipe is used to automatically discharge the leaking water to the outside (Patent Application No. 2020-88542).

[0005] That is, the drain hose is extended upward from the drain outlet, the middle part of the drain hose is bent near the top of the storage tank, the drain hose is extended downward, the vicinity of the bent part is fixed to the outside, and the lower end of the drain hose is connected to an external drain. When the water level of the leaking water in the storage tank reaches the bent part, the leaking water in the storage tank is discharged all at once by the siphon effect.

[0006] Patent Document 1 discloses a full-water prediction system for an underwater pump having a pump driven by an electric motor, which is provided with a shaft seal chamber with a built-in shaft seal device between the motor casing and the pump casing, a liquid reservoir chamber for collecting water leaking from this shaft seal chamber, and a water level detection means for detecting the water level in the liquid reservoir chamber, and which predicts the time when the leaked water collected in the liquid reservoir chamber will reach a predetermined full-water level.

[0007] It is possible to predict when the liquid reservoir chamber of a submersible pump will become full with water using the technology of Patent Document 1. On the other hand, in the case of the circulation pump unit described above, even if the storage tank becomes full with water, the siphon effect can be used to automatically drain the water, so the time when the storage tank becomes full with water is not an issue. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2021-99084 Summary of the Invention [Problem to be solved by the invention]

[0009] The mechanical seal of the circulation pump described above gradually increases the amount of water leakage as it wears over time. The technology of storing the leaked water in the storage tank, detecting and reporting a predetermined water level with a water level detection means, and draining the water from a drain hose using the siphon effect can prevent the storage tank from overflowing, but cannot detect the degree of deterioration of the seal.

[0010] As a result, determining the degree of deterioration of the sealing materials relies on the experience of the worker, making it difficult to replace or maintain the seals at the right time without overdoing it, and there is a demand for technology to detect the degree of deterioration of the seals in circulation pumps.

[0011] An object of the present invention is to provide a technique that makes it possible to determine the degree of deterioration of a sealing portion of a circulation pump unit. [Means for solving the problem]

[0012] The circulation pump unit of the invention of claim 1 comprises a circulation pump for circulating hot and cold water, a suction piping connected to the suction side of the circulation pump, and a discharge piping connected to the discharge side of the circulation pump, disposed within a casing, a leakage pan for receiving water leaking from the circulation pump below the circulation pump, and a storage tank for storing the leakage water received by the leakage pan, and is also equipped with a water level detection means for detecting a predetermined water level in the storage tank, and when a predetermined amount or more of leakage water is stored in the storage tank, the stored leakage water is discharged all at once by utilizing the siphon effect, characterized in that the water level detection means measures and stores the duration of the water level above the predetermined water level after detecting the predetermined water level, and judges the degree of deterioration of the sealing portion of the circulation pump based on the change in the duration over time.

[0013] According to the above configuration, even after the water level detection means detects the predetermined water level, the leaked water continues to accumulate gradually, and when the amount of accumulated leaked water exceeds the predetermined amount, the water is drained all at once due to the siphon effect. The water level detection means turns ON when it detects a specified water level, and turns OFF if it no longer detects the specified water level during the subsequent drainage process.The time duration from ON to OFF is measured and stored, and the degree of deterioration of the sealing part of the circulation pump is determined based on changes in that time duration over time.

[0014] In other words, since the amount of water leakage increases as the degree of deterioration of the seal portion progresses, the duration becomes shorter, and therefore the degree of deterioration of the seal portion of the circulation pump can be determined based on the change in the duration over time. In this way, by effectively utilizing the water level detection means and the siphon-type drainage means, the degree of deterioration of the seal portion of the circulation pump can be accurately determined with a simple configuration.

[0015] The circulation pump unit of the invention of claim 2 is characterized in that, in the invention of claim 1, a drainage section for draining water leaking from the storage tank to the outside of the casing is provided at a position lower than the storage tank, a drainage hose extends from the bottom of the storage tank to the drainage section, and a middle portion of the drainage hose is fixed at a position above the specified water level.

[0016] According to the above configuration, when the water level in the storage tank due to leakage reaches or exceeds the predetermined water level, drainage starts, continues due to the siphon effect, and stops when the storage tank becomes empty. With a simple configuration consisting of the above-mentioned drain hose and a mechanism for fixing its midway point, automatic drainage from the storage tank can be achieved.

[0017] The circulation pump unit of the invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the circulation pump unit is communicatively connected to a server via a communication network, and transmits time data of the duration to the server at the start or end of the duration, and stores the time data in the server.

[0018] According to the above configuration, after the water level detection means detects a predetermined water level, time data of the duration at the start or end of the duration of the water level equal to or higher than the predetermined water level is transmitted to the server, and the time data is stored in the server. When transmitting at the start, time data of the previous duration is transmitted, and when transmitting at the end, time data of the current duration is transmitted. In this way, by collecting and storing the duration time data in the server, it is possible to determine the degree of deterioration of the seals of multiple circulation pump units installed in multiple locations. Effect of the Invention

[0019] According to the circulation pump unit of the present invention, the water level detection means measures and stores the duration of time that the water level remains above a predetermined water level after detecting the predetermined water level, and the degree of deterioration of the sealing portion of the circulation pump can be determined based on changes in that duration over time.By storing the duration data in a server, the server can determine the degree of deterioration of the sealing portions of the circulation pumps of multiple circulation pump units installed in multiple locations. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a perspective view of a circulation pump unit according to an embodiment of the present invention. [Diagram 2] 2 is a perspective view of the circulation pump unit of FIG. 1 as seen from the opposite side. [Diagram 3] FIG. 2 is a perspective view of the main parts of a circulation pump and a water leakage pan. [Figure 4] FIG. 1 is an explanatory diagram of a water leakage pan and a storage tank. [Diagram 5] FIG. 2 is a vertical cross-sectional view showing the inside of the storage tank. [Figure 6] FIG. 11 is an explanatory diagram of a fastener at the middle portion of the drain hose. [Figure 7] This is a time chart explaining the float switch ON / OFF, drainage operation, water level, and duration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the configuration of the linked hot water supply system will be described. 1, linked hot water supply system 30 has multiple hot water supply devices 31a-31d connected in parallel, a circulation passage 32 that enables circulating supply of hot water to the multiple hot water supply devices 31a-31d, multiple circulation pumps 1a, 1b connected in parallel to circulation passage 32, a changeover valve 33 that switches the flow path depending on which circulation pump 1a, 1b is being used, and a system controller 34 as control means that drives these and controls the hot water supply operation. The number of hot water supply devices and the number of pumps in linked hot water supply system 30 can be set as appropriate depending on, for example, the required hot water supply capacity, etc.

[0022] In a facility having a plurality of hot water taps (not shown) in addition to hot water taps 32a-32c as hot water supply destinations, a circulation passage 32 for circulating hot water is laid so that hot water can be supplied immediately from any hot water tap. Hot water supply devices 31a-31d that supply hot water to this circulation passage 32 are required to be able to supply hot water at low to high flow rates and to be able to avoid situations where hot water cannot be supplied due to malfunctions, so a linked hot water supply system 30 having the plurality of hot water supply devices 31a-31d is connected to the circulation passage 32. When hot water is supplied from the hot water taps 32a-32c, clean water is supplied to the circulation passage 32 as shown by arrow W.

[0023] An operation terminal 35 for performing various settings and a communication device 36 are communicatively connected to the system controller 34, and the system controller 34 is connected to an external communication network 37 (e.g., the Internet) via the communication device 36. A management server 38 that manages the provision of maintenance services based on information received from the linked hot water supply system 30 is connected to the external communication network 37. The management server 38 is provided by the maintenance service provider and manufacturer of the linked hot water supply system 30 so that any malfunctions that occur can be dealt with promptly and so that malfunctions can be prevented from occurring.

[0024] Next, the circulation pump unit 3 having the circulation pumps 1a and 1b will be described. The circulation pumps 1a and 1b are mechanical seal type pumps. 2 and 3, the circulation pump unit 3 has a frame 5 that forms a rectangular parallelepiped casing, and panels (not shown) are attached to the top and four sides (front, back, left and right) of this frame 5. Fixed inside the casing are circulation pumps 1a, 1b that circulate hot and cold water, suction distribution pipes 6a, 6b connected to the suction sides of the circulation pumps 1a, 1b, and discharge distribution pipes 7a, 7b connected to the discharge sides of the circulation pumps 1a, 1b. Arrows F, L, and U indicate the front, left and top of the circulation pump unit 3, respectively.

[0025] Below the circulation pumps 1a, 1b, two expansion tanks 8, 9 are provided to absorb the volumetric expansion of the heated water. A control box 10 is provided beside the expansion tanks 8, 9 to protect the control board that controls the operation of the circulation pumps 1a, 1b from being submerged in water. In addition, a drainage unit 11 is provided to drain water to the outside, and is connected to the facility's drainage pipes, etc.

[0026] The two circulation pumps 1a, 1b are placed and fixed on a tray-shaped water leakage pan 12 that receives water leakage from the circulation pumps 1a, 1b. The water leakage pan 12 is fastened and fixed to the middle section of the frame 5, for example, with screws. The circulation pump unit 3 is driven to circulate hot and cold water constantly or intermittently at a specified cycle. At this time, the two circulation pumps 1a, 1b are not driven simultaneously, but for example, the circulation pump 1a and the circulation pump 1b are driven alternately at specified time intervals to extend the service life until the accumulated operating time reaches a certain time.

[0027] Hot and cold water is supplied to the suction pipe 6 from outside the circulation pump unit 3. This suction pipe 6 branches into two suction side distribution pipes 6a, 6b, which are connected to the suction sides of the corresponding circulation pumps 1a, 1b, respectively, and the suction side distribution pipes 6a, 6b are connected to the above-mentioned changeover valve 33. Discharge side pipes 7a, 7b are connected to the discharge sides of the two circulation pumps 1a, 1b, respectively.

[0028] As shown in Figures 1 and 2, the discharge side pipes 7a, 7b each have a check valve 14a, 14b, which prevents hot water pressurized by the operation of one circulation pump from flowing into the other circulation pump, which is stopped, and flowing back into the suction pipe 6.

[0029] 3 to 5, the water leakage pan 12 is formed in a shallow tray shape using, for example, a rectangular metal plate. A support frame 18 that supports the water leakage pan 12 from below is attached parallel to the long side of the water leakage pan 12, and both ends of the support frame 18 are fastened and fixed to the frame 5 of the circulation pump unit 3 with screws or the like. Two circulation pumps 1a and 1b are placed on the water leakage pan 12 so as to be aligned in the long side direction of the water leakage pan 12.

[0030] The central portion of the water leakage pan 12 between the two circulation pumps 1a, 1b has a downwardly recessed water collection section 19, and leakage water from the circulation pumps 1a, 1b is collected in the water collection section 19. A circular opening is provided in the central portion of the water collection section 19. Splash guards 20a, 20b are provided to cover the lower side surfaces of the circulation pumps 1a, 1b from three sides other than the water collection section 19 side to prevent leakage water from the circulation pumps 1a, 1b from splashing out of the water leakage pan 12.

[0031] A storage tank 21 for storing the leaked water received by the water leakage pan 12 is disposed below the water leakage pan 12. As shown in Fig. 5, the storage tank 21 has a cylindrical leakage water inlet 21a at the top and a drain outlet 21b at the bottom. A cylindrical bracket 22 with a flange-shaped upper portion is attached from above to the opening in the center of the water collection section 19.

[0032] An internal thread is formed on the inner circumference of the cylindrical bracket 22, and an external thread is formed on the outer circumference of the cylindrical leakage water inlet 21a of the storage tank 21. The storage tank 21 is fixed to the leakage pan 12 by screwing the cylindrical bracket 22 into the leakage water inlet 21a. Leaking water passes through the inside of the cylindrical bracket 22 and flows into the storage tank 21 from the leakage water inlet 21a. A filter 21c for collecting foreign matter other than the leaking water is attached to the leakage water inlet 21a.

[0033] With the storage tank 21 fixed to the water leakage pan 12, the bottom 21d of the storage tank 21 is inclined downward toward the drain outlet 21b. A float switch 21e (water level detection means) for detecting a predetermined water level of the stored leakage water is provided above the drain outlet 21b. The float switch 21e is connected to a control board in the control box 10, and the control board is connected to the system controller .

[0034] The float switch 21e has a float 21f that moves according to the water level of the stored leaking water, and is configured to turn ON when the water level in the storage tank 21 reaches or exceeds a predetermined water level, for example, half the height of the storage tank 21, to notify the occurrence of a leak. The occurrence of a leak is notified by the illumination of a lamp (not shown), and the notification state continues even if the float switch 21e turns OFF until a specified release operation is performed.

[0035] As shown in Fig. 4, drain outlet 21b is connected to drain hose 24 for discharging leaking water from storage tank 21 to drain section 11. Drain hose 24 is made of a flexible synthetic resin material and can be easily bent, and the internal passage is not crushed or blocked even in the bent state.

[0036] One end of the drain hose 24 is connected to the drain outlet 21b, and the other end of the drain hose 24 extends to a drain hopper 11b connected to the drain section 11 and is fixed by a fastener 11a. A middle portion 24a of the drain hose 24 is fixed to the support frame 18 of the waterproof pan 12 by a fastener 25 (fixing means) in a state where it is raised to a position higher than a predetermined water level.

[0037] Since the middle portion 24a of the drain hose 24 is located higher than the predetermined water level, the leaked water can be stored in the storage tank 21 up to the predetermined water level or higher (up to the top of the storage tank 21). When the water level in the storage tank 21 reaches the height of the middle portion 24a of the drain hose 24, the water is drained into the drain section 11 below by the siphon effect, and the storage tank 21 becomes almost empty.

[0038] 6, fastener 25 is a removable fastener that is, for example, a belt-shaped nylon clamp that is bent to suspend midsection 24a of drain hose 24, with both ends overlapping, and fastened to support frame 18 with screws 25a or the like. In addition to this, various other fasteners that can detachably fasten midsection 24a of drain hose 24 to support frame 18 can be used.

[0039] Here, in this circulation pump unit 3, the float switch 21e (water level detection means) measures and stores the duration of the water level above the specified water level after detecting the specified water level, and is configured to determine the degree of deterioration of the sealing part of the circulation pump based on changes in that duration over time.

[0040] As shown in Figure 7, when the water level in the storage tank 21 reaches a predetermined water level, the float switch 21e turns ON, and the detection signal is sent to a control board in the control box 10, and then transmitted from the control board to the system controller 34, where it is notified by, for example, lighting up a lamp, and the display unit of the system controller 34 notifies the user that the float switch 21e is ON.

[0041] Even after float switch 21e is turned ON, leaking water continues to be stored in storage tank 21. The water level of the leaking water in storage tank 21 gradually rises, and when it reaches the height of midpoint 24a of drain hose 24, drainage operation by siphoning begins via drain hose 24. After that, drainage progresses, and when the water level of the leaking water falls below a predetermined water level, float switch 21e turns OFF and a detection signal is sent to system controller 34. Drainage continues even after the above OFF, and when storage tank 21 is almost empty, the drainage operation ends.

[0042] The system controller 34 measures the duration from when the float switch 21e is turned ON to when it is turned OFF (the duration that the water level remains above a specified water level), and when it turns OFF, transmits the data on this current duration to the management server 38 via the external communication network 37. The management server 38 stores the above duration data in a memory, and periodically (for example, at midnight every day) applies the latest duration data to a deterioration degree judgment criterion that is set and stored in advance to judge the deterioration degree of the seal parts of the circulation pumps 1a, 1b. Note that a deterioration degree judgment program is stored in the management server in advance.

[0043] That is, the more the degree of deterioration of the seals of the circulation pumps 1a and 1b progresses, the more the amount of water leakage increases, and the shorter the duration. In view of this, the deterioration degree judgment criteria are set with the duration as a parameter, for example, deterioration level A (e.g., 12 months of remaining life), deterioration level B (e.g., 6 months of remaining life), and deterioration level C (e.g., 3 months of remaining life). The deterioration level determined as described above may be transmitted to the system controller 34 and displayed.

[0044] The operation and effect of the circulation pump unit 3 described above will be described. By effectively utilizing a water level detection means (float switch 21e) provided in the storage tank 21 and a siphon-type drainage means including a drain hose 24, the duration of the water level above a predetermined water level after the water level detection means detects a leakage in the storage tank 21 is measured and stored, and the degree of deterioration of the sealing parts of the circulation pumps 1a, 1b is determined based on the change in the duration over time.

[0045] In this way, the water level detection means and the siphon-type drainage means are effectively utilized, and the degree of deterioration of the seal portions of the circulation pumps 1a, 1b can be accurately determined with a simple configuration. The water level detection means measures and stores the duration of the water level above a specified water level after detecting the specified water level, and stores this duration data in the management server 38, allowing the management server 38 to determine the degree of deterioration of the sealing portions of the circulation pumps 1a, 1b of multiple circulation pump units 3 installed in multiple locations.

[0046] A modification of the above embodiment will now be described. 1) The float switch 21e may be configured to transmit data on the previous duration to the management server 38 when the float switch 21e is turned ON. 2) The water level detection means may be configured to be other than the float switch 21e, for example, an electrode type or an ultrasonic type. 3) In addition, a person skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment without departing from the spirit of the present invention, and the present invention includes such modifications. [Explanation of symbols]

[0047] 1a, 1b Circulation pump 3 Circulation pump unit 6a, 6b Suction distribution pipe 7a,7b Discharge distribution piping 11 Drainage section 12 Leaking Pan 21 Storage Tank 21e Float switch (water level detection means) 24 Drain hose 24a middle part 38 Management Server

Claims

1. A circulation pump unit having a casing that circulates hot and cold water, a suction pipe connected to the suction side of the circulation pump, and a discharge pipe connected to the discharge side of the circulation pump, a water leakage pan disposed below the circulation pump to receive water leaking from the circulation pump, and a storage tank that stores the leaked water received by the water leakage pan, and also equipped with a water level detection means for detecting a predetermined water level in the storage tank, and when a predetermined amount or more of leaked water is stored in the storage tank, the siphon effect is utilized to discharge the stored leaked water in one go, Measure and store the duration of the water level equal to or higher than the predetermined water level since the water level detection means detects the predetermined water level; A circulation pump unit characterized in that a degree of deterioration of a seal portion of the circulation pump is determined based on a change in the duration over time.

2. The circulation pump unit described in claim 1, characterized in that a drainage section for draining leaked water from the storage tank to the outside of the casing is provided at a position lower than the storage tank, a drainage hose extending from the bottom of the storage tank to the drainage section, and a middle portion of the drainage hose are fixed at a position above the specified water level.

3. The circulation pump unit according to claim 1 or 2, characterized in that the circulation pump unit is communicatively connected to a server via a communication network, transmits time data of the duration to the server each time the duration starts or ends, and stores the time data in the server.

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