JP7667441B2 - Circulation Pump Unit - Google Patents

Description

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, etc.

In the past, instant hot water circulation systems have been used in facilities equipped with multiple hot water taps, such as hotels and hospitals, that are designed to provide instant hot water from any hot water tap by circulating high-temperature water heated by a hot water supply device either constantly or intermittently at a specified cycle. In such instant hot water circulation systems, a circulation pump unit equipped with a mechanically sealed circulation pump that can handle the required large flow rate and high discharge pressure is used.

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 becomes more likely to occur. For this reason, the circulation pump unit is configured to detect and alert the user of leakage from the circulation pump. For example, the leakage water received by the leakage pan is stored in a storage tank, etc., and when the water level in the storage tank reaches a specified water level, a light comes on, an alarm sounds, etc., alerting the user of the leakage.

The applicant of this application has proposed a technology in which a storage tank is provided with a drain outlet, 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 drain the leaked water to the outside (Patent Application No. 2020-88542).

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, extended downward, and the area near 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.

Patent Document 1 discloses a full water forecasting system for a submersible pump having a pump driven by an electric motor, which includes a shaft seal chamber with a built-in shaft seal device between the motor casing and the pump casing, a liquid reservoir chamber for storing water leaking from the 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 stored in the liquid reservoir chamber will reach a predetermined full water level.

The technology of Patent Document 1 makes it possible to predict when the liquid reservoir in a submersible pump will become full. On the other hand, in the case of the circulation pump unit described above, even if the storage tank becomes full, the siphon effect can be used to automatically drain the water, so the time when the storage tank will become full is not an issue.

JP 2021-99084 A

As the mechanical seal of the circulation pump wears over time, the amount of water leakage gradually increases. The technology of storing the leaked water in the storage tank, detecting and reporting a specified water level using 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.

As a result, determining the degree of deterioration of the sealing material 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.

The objective of the present invention is to provide a technology that makes it possible to determine the degree of deterioration of the sealing portion of a circulation pump unit.

The circulation pump unit of the invention of claim 1 has a circulation pump for circulating 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, and is provided with a water leakage pan below the circulation pump to receive water leaking from the circulation pump, and a storage tank to store the water leaked by the water leakage pan, and is equipped with a water level detection means for detecting a predetermined water level in the storage tank, and when a predetermined amount of water or more is stored in the storage tank, the stored water is discharged all at once using the siphon effect. The circulation pump unit is 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 seal of the circulation pump based on the change in the duration over time.

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 when 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.

In other words, the more the deterioration of the seal portion progresses, the greater the amount of water leakage, and the duration shortens, so 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.

The circulating pump unit of the invention of claim 2 is the invention of 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 extends from the bottom of the storage tank to the drainage section, and a mid-way portion of the drainage hose is fixed at a position above the height of the predetermined water level.

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

The circulation pump unit of the invention of claim 3 is the invention of 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.

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

According to the circulation pump unit of the present invention, the water level detection means measures and stores the duration of the water level above a predetermined water level after detecting the predetermined water level, and the degree of deterioration of the seal of the circulation pump can be determined based on the change in the duration over time. By storing the duration data in a server, the server can determine the degree of deterioration of the seal of the circulation pump of multiple circulation pump units installed in multiple locations.

FIG. 2 is a perspective view of a circulation pump unit according to an embodiment of the present invention. 2 is a perspective view of the circulating pump unit of FIG. 1 as seen from the opposite side. FIG. 2 is a perspective view of the main parts of a circulation pump and a water leakage pan. FIG. 1 is an explanatory diagram of a water leakage pan and a storage tank. FIG. 2 is a vertical cross-sectional view showing the inside of the storage tank. FIG. 11 is an explanatory diagram of a fastener at the middle portion of the drain hose. 4 is a time chart illustrating the ON/OFF state of the float switch, the drainage operation, the water level, and the duration.

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 this 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.

In a facility that has multiple hot water taps (not shown) in addition to hot water taps 32a-32c as hot water supply destinations, a circulation passage 32 is laid to circulate hot water so that hot water can be supplied immediately from any hot water tap. The 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 avoid situations where hot water cannot be supplied due to malfunctions, so a linked hot water supply system 30 having multiple 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.

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 quickly and so that malfunctions can be prevented in advance.

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 and 1b that circulate hot and cold water, suction distribution pipes 6a and 6b connected to the suction sides of the circulation pumps 1a and 1b, and discharge distribution pipes 7a and 7b connected to the discharge sides of the circulation pumps 1a and 1b. Arrows F, L, and U indicate the front, left, and top of the circulation pump unit 3, respectively.

Two expansion tanks 8, 9 are provided below the circulation pumps 1a, 1b to absorb the volumetric expansion of the heated water. A control box 10 is provided to the side of 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 section 11 is provided to drain water to the outside, and is connected to the facility's drainage pipes, etc.

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 intervals to extend the service life until the cumulative operating time reaches a certain time.

Hot 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 and 6b, which are connected to the suction sides of the corresponding circulation pumps 1a and 1b, respectively, and the suction side distribution pipes 6a and 6b are connected to the switching valve 33. Discharge side pipes 7a and 7b are connected to the discharge sides of the two circulation pumps 1a and 1b, respectively.

As shown in Figures 1 and 2, the discharge pipes 7a and 7b each have a check valve 14a or 14b, which prevents hot water pumped by one of the circulation pumps from flowing into the other circulation pump that is stopped and flowing back into the suction pipe 6.

As shown in Figures 3 to 5, the water leakage pan 12 is formed in the shape of a shallow tray, for example, from 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 that they are lined up in the long side of the water leakage pan 12.

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 water leakage 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 water leakage from the circulation pumps 1a, 1b from splashing outside the water leakage pan 12.

A storage tank 21 is disposed below the water leakage pan 12 to store the leaked water received by the water leakage pan 12. As shown in FIG. 5, the storage tank 21 has a cylindrical leakage 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 central portion of the water collection section 19.

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 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 inlet 21a. Leaking water passes through the inside of the cylindrical bracket 22 and flows into the storage tank 21 from the leakage inlet 21a. A filter 21c is attached to the leakage inlet 21a to collect foreign matter other than the leaking water.

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) is disposed above the drain outlet 21b to detect a predetermined water level of the stored leakage water.
The float switch 21 e is connected to a control board in the control box 10 , and the control board is connected to the system controller 34 .

The float switch 21e has a float 21f that moves according to the level of the stored leaking water, and is configured to turn ON when the water level in the storage tank 21 reaches a predetermined 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 is turned OFF until a specified release operation is performed.

As shown in FIG. 4, a drain hose 24 is connected to the drain outlet 21b to drain leaking water from the storage tank 21 to the drain section 11. The drain hose 24 is made of a flexible synthetic resin material and can be easily bent, and even when bent, the internal passage is not crushed or blocked.

The drain hose 24 has one end connected to the drain outlet 21b and the other end extending to the drain hopper 11b connected to the drain section 11 and fixed by a fastener 11a. The middle part 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 the predetermined water level.

Because the middle part 24a of the drain hose 24 is located higher than the specified water level, the storage tank 21 can store leaked water up to the specified 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 part 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.

As shown in FIG. 6, the fastener 25 is a removable fastener that is, for example, a band-shaped nylon clamp that is bent to lift the middle portion 24a of the drain hose 24, with both ends overlapping and fastened to the support frame 18 with screws 25a or the like. In addition to this, various other fasteners can be used to detachably fasten the middle portion 24a of the drain hose 24 to the support frame 18.

Here, in this circulation pump unit 3, the float switch 21e (water level detection means) detects the predetermined water level and then measures and stores the duration of the water level above the predetermined water level, and is configured to determine the degree of deterioration of the seal of the circulation pump based on changes in that duration over time.

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

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

The system controller 34 times the duration of the float switch 21e from ON to OFF (the duration of the water level above a specified water level), and when it turns OFF, transmits the data of this duration to the management server 38 via the external communication network 37.
The management server 38 stores the above-mentioned 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 has been 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.

That is, the more the deterioration of the seals of the circulation pumps 1a and 1b progresses, the more the leakage amount 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 remaining life), deterioration level B (e.g., 6 months remaining life), and deterioration level C (e.g., 3 months remaining life).
The deterioration level determined as described above may be transmitted to the system controller 34 and displayed.

The operation and effect of the circulation pump unit 3 described above will now 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 specified 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 changes over time in that duration.

In this way, the water level detection means and the siphon-type drainage means can be effectively utilized to accurately determine the degree of deterioration of the seal portions of the circulation pumps 1a, 1b 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 parts of the circulation pumps 1a, 1b of multiple circulation pump units 3 installed in multiple locations.

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 detect the water level using an electrode or ultrasonic wave instead of the float switch 21e.
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.

1a, 1b Circulation pump 3 Circulation pump unit 6a, 6b Suction distribution pipe 7a, 7b Discharge distribution pipe 11 Drainage section 12 Water leakage pan 21 Storage tank 21e Float switch (water level detection means)
24 Drain hose 24a Mid-way section 38 Management server

Claims (3)

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. The circulation pump unit according to 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 extends from the bottom of the storage tank to the drainage section, and a midway portion of the drainage hose is fixed at a position above the height of the specified water level. 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.