Fluid Pump System

Abstract

To evaluate flow characteristics of a pump while suppressing power consumption.SOLUTION: A fluid pump system includes a pump, a first suction passage for introducing a first fluid into a pump, a second suction passage for introducing a second fluid having a specific gravity smaller than that of the first fluid into the pump, a discharge passage for discharging the fluid from the pump, a selector valve for selectively communicating one of the two suction passages with the pump, a state quantity sensor arranged in the discharge passage and measuring a state quantity of the second fluid, and a control device. At pressure-feeding of the first fluid, the control device allows the selector valve to communicate the first suction passage with the pump and operates the pump so that the first fluid flows into the discharge passage, and at evaluating flow characteristics of the pump, the control device allows the selector valve to communicate the second suction passage with the pump and operates the pump so that the second fluid flows into the discharge passage. A flow rate of the second fluid is measured by the state quantity sensor, and the flow characteristics of the pump at pressure-feeding of the first fluid can be evaluated on the basis of the flow rate of the second fluid.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this application relates to a fluid pump system. [Background technology]

[0002] When using an electric pump to transport a fluid while controlling the flow rate, the discharge flow rate is controlled, for example, by varying the power. In this case, the pump's flow rate characteristics, which are expressed as the relationship between power and flow rate, can change due to system deterioration or failure. Furthermore, even pumps of the same model are generally thought to have slightly different flow rate characteristics. To improve the accuracy of flow rate control or detect pump abnormalities, it is necessary to measure the flow rate as needed and evaluate the pump's flow rate characteristics. For example, Japanese Patent Application Laid-Open No. 06-066287 describes a system that can measure the flow rate based on the suction water level and the pump's discharge pressure while pumping a fluid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 06-066287 Summary of the Invention [Problem to be solved by the invention]

[0004] The system described in the publication is premised on measuring the flow rate during normal operation. Therefore, when evaluating the flow rate characteristics of a pump using the measurement technology described in the publication, it is necessary to pump fluid just for the evaluation, even when there is no need to pump fluid, which increases power consumption. Therefore, it is desirable to evaluate the flow rate characteristics of a pump while suppressing power consumption. [Means for solving the problem]

[0005] One aspect is a fluid pump system comprising: a pump; a first suction passage for introducing a first fluid into the pump; at least one second suction passage for introducing a second fluid, the second fluid having a lower specific gravity than the first fluid, into the pump; a discharge passage for discharging the fluid from the pump; at least one switching valve configured to selectively connect either the first suction passage or the second suction passage to the pump; a state quantity sensor arranged in the discharge passage to measure a flow rate; and a control device. When pumping the first fluid, the control device connects the first suction passage to the pump using the switching valve and operates the pump to cause the first fluid to flow into the discharge passage. When evaluating flow characteristics of the pump, the control device connects the second suction passage to the pump using the switching valve and operates the pump to cause the second fluid to flow into the discharge passage, measures the flow rate of the second fluid using the state quantity sensor, and evaluates the flow characteristics of the pump when pumping the first fluid based on the flow rate of the second fluid. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing the configuration of a pump system for supplying breeding water to an aquarium as one embodiment. [Figure 2] 1. FIG. 4 is a diagram showing a state in which air is introduced into a discharge passage from another suction passage in the pump system of FIG. [Figure 3] FIG. 10 is a diagram showing the configuration of a pump system equipped with a temperature sensor for monitoring the temperature of rearing water as another embodiment. [Figure 4] 4 is a diagram showing a state in which air is introduced into a discharge passage from another suction passage in the pump system of FIG. 3. FIG. [Figure 5] FIG. 10 is a diagram showing the configuration of a pump system equipped with a salinity sensor that monitors the salinity of breeding water as yet another embodiment. [Figure 6] 6 is a diagram showing a state in which fresh water is introduced into a discharge passage from another suction passage in the pump system of FIG. 5. FIG. [Figure 7]FIG. 10 is a diagram showing the configuration of a pump system according to yet another embodiment, which combines the features of FIGS. 1, 3, and 5. DETAILED DESCRIPTION OF THE INVENTION

[0007] Various embodiments will be described below with reference to the drawings. Note that parts that can be configured similarly in the following embodiments will be assigned similar reference numerals and will not be described repeatedly.

[0008] [Pump system] 1 and 2 show, as one embodiment, a pump system 10 for supplying culture water to an aquarium 12 for cultivating seafood. A supply passage 14 for passing the culture water is connected to the aquarium 12, and a pump 16 is disposed in the supply passage 14. A discharge passage 36 for circulating the culture water can also be connected to the aquarium. The upstream side of the supply passage 14 is connected to a culture water source (not shown). When the pump 16 is operated, culture water is supplied from the source through the supply passage 14 to the aquarium 12 (arrow 24).

[0009] [Flow Control] The flow rate of the electric pump is controlled, for example, by varying the power supplied to the pump (specifically, variables such as the average voltage and current). In this case, the flow rate characteristics of the pump 16 are expressed as a relationship between power and flow rate, which depends on the density (specific gravity) of the fluid being pumped. In some embodiments, a flow rate sensor (not shown) can be provided in the discharge passage 20 (in the supply passage 14 downstream of the pump 16), and the actual flow rate measured by this flow rate sensor can be fed back to the control. Such control can be performed by a control device (controller) 22 provided in the pump system 10. Specifically, the control device 22 can be an electronic control unit (ECU) equipped with a processing unit (processor) that executes programs and a storage device that stores programs and data. The control device 22 is configured to receive data from the various sensors described herein and send control signals to the pump and various valves. The various methods described below can also be implemented by executing programs stored in the storage device.

[0010] [Evaluation of pump flow characteristics] An intake passage 30 for introducing air joins the supply passage 14 upstream of the pump 16. The upstream side of the intake passage 30 is open to the atmosphere. A three-way valve 32 is provided at this joining point, allowing either the rearing water intake passage 18 (the supply passage 14 upstream of the pump 16) or the air intake passage 30 to be selectively connected to the pump 16. The three-way valve 32 may be an integral part directly connected to the intake port of the pump 16 as shown in FIG. 1, or in another embodiment, it may be connected to the pump 16 via a long passage. In addition, a stop valve 34 capable of closing communication is provided in the discharge passage 20. The stop valve 34 may be, for example, a solenoid valve. A pressure sensor 38 is provided in the discharge passage 20 so as to communicate with the section from the pump 16 to the stop valve 34.

[0011] To evaluate the pump's flow characteristics, first, as shown in FIG. 2, switch the three-way valve 32 to connect the air intake passage 30 to the pump 16, and introduce air from the atmosphere into the discharge passage 20 (arrow 40). After a certain amount of time has passed, the air begins to leak past the shut-off valve 34 and into the water tank 12 (arrow 42). After a predetermined time has passed, which is the time required for the air to leak into the water tank 12, the pump 16 is temporarily stopped and the shut-off valve 34 is closed. This fills the supply passage 14 downstream of the three-way valve 32 with air at atmospheric pressure P0. The pump 16 is then operated for a predetermined time t to further push air into that section, and the pressure increase ΔP of the air above atmospheric pressure is measured by the pressure sensor 38. If the volume of the discharge passage 20 from the pump 16 to the shut-off valve 34 is V, the flow rate Q of air passing through the pump 16 can be calculated as Q = (V × ΔP / P0) / t. Instead of measuring the pressure increase from atmospheric pressure, the pressure increase between two pressure measurements before and after the passage of a predetermined time t can also be used. To convert this air flow rate to the rearing water flow rate Q' when the pump 16 is operated at the same power, in one embodiment, the specific gravity (density ratio) of the rearing water relative to air at atmospheric pressure can be used. Alternatively, in another embodiment, the relationship (map) between the air flow rate Q and the rearing water flow rate Q' when the pump 16 is operated at the same power can be measured in advance and stored in the control device 22, and the rearing water flow rate Q' can be determined based on this relationship. The flow rate characteristics of the pump 16 are evaluated based on the flow rate determined in this manner. According to the above method, because ordinary air has a lower specific gravity (density) than rearing water, power consumption is reduced compared to when the flow rate characteristics of the pump 16 are evaluated while rearing water is being supplied.

[0012] Such evaluation of flow characteristics can be performed, for example, during the initial operation of the pump system 10, to understand or learn the inherent flow characteristics (due to product variations) of the pump 16 being used. Furthermore, even after the initial operation, the flow characteristics can be evaluated periodically or on a one-off basis to track changes over time in the system and improve the accuracy of flow control. In these cases, the evaluated flow characteristics are stored in the control device 22 and used for subsequent flow control (or the next evaluation), and the stored flow characteristics can be updated each time a new evaluation is performed. Note that when performing periodic evaluations, rearing water may be supplied when a specified time has elapsed. In this case, the supply of rearing water may be interrupted before proceeding with the evaluation of flow characteristics, or the evaluation may be performed after waiting for the supply of rearing water to be stopped. In another embodiment, the evaluated flow characteristics can be used to detect abnormalities such as deterioration or failure of the pump 16.

[0013] Although not shown, in another embodiment, a flow rate sensor can be provided instead of the pressure sensor 38 to directly measure the air flow rate Q. In this case, the shut-off valve 34 is not necessarily required, and if the shut-off valve 34 is provided, the pump 16 is operated with the shut-off valve 34 open to measure the flow rate. The pressure sensor 38 and the flow rate sensor (not shown) are both state quantity sensors that measure air state quantities (pressure and flow rate) in order to measure the flow rate of the rearing water.

[0014] [Supply Suspension and Resumption] When the supply of rearing water is suspended for a short or long period of time, the three-way valve 32 is switched to connect the air intake passage 30 to the pump 16, and the pump 16 is operated to allow air to flow into the discharge passage 20, after which the pump 16 is stopped. This ensures that at least the interior of the pump 16 is filled with air. By operating the pump 16 for a sufficient period of time and then stopping it, salty rearing water can be removed from the supply passage 14, including the pump 16, from the three-way valve 32 to the stop valve 34. This reduces corrosion of the pump 16 and the interior of the piping due to salt, compared to simply stopping the pump 16 while the rearing water is being supplied. After stopping the pump 16, if necessary, the three-way valve 32 can be switched to a fully closed state, i.e., a state in which neither the intake passage 18 nor the intake passage 30 is connected to the pump 16.

[0015] To resume the supply of rearing water, the three-way valve 32 is switched to connect the rearing water intake passage 18 (the supply passage 14 upstream of the pump 16) to the pump 16. The pump 16 is operated with the shut-off valve 34 open, and rearing water is supplied to the aquarium 12 through the discharge passage 20.

[0016] [Controlling the temperature of the breeding water] 3 and 4 show another embodiment of a pump system 50 that supplies water to the aquarium 12 while monitoring its temperature. In this embodiment, a temperature sensor 56 is provided instead of the pressure sensor 38 of the previous embodiment. The control device 54 constantly or periodically measures the temperature of the water flowing through the discharge passage 20 using the temperature sensor 56, and if the measured temperature significantly deviates from a set target water temperature, the control device 54 determines that the water temperature is abnormal. For example, if the measured water temperature is within a predetermined range including the target water temperature, the temperature of the supplied water is determined to be normal; otherwise, it is determined to be abnormal. If an abnormality is determined, the temperature of the water drawn in through the intake passage 18 is adjusted.

[0017] [Temperature sensor abnormality detection] The upstream side of the intake passage 30 is connected to an air supply source, for example by opening it to the environment. For example, this supply source environment can simply be the room in which the pump system 50 is installed. A separate temperature sensor 62 is provided to measure the temperature of the air supply source. To detect an abnormality in the temperature sensor 56, first, as shown in FIG. 4, the three-way valve 32 is switched to connect the air intake passage 30 to the pump 16, and air is introduced into the discharge passage 20 (arrow 40). After a certain amount of time has passed, air begins to leak past the shut-off valve 34 and into the water tank 12 (arrow 42). After a predetermined time has passed, which is the time required for the air to leak into the water tank 12, the pump 16 is stopped and the shut-off valve 34 is closed. This causes the supply passage 14 downstream of the three-way valve 32 to be filled with the air taken in. Here, the temperature sensor 56 in the supply passage 14 measures the air temperature. If the measured temperature significantly deviates from the temperature of the air supply source measured by another temperature sensor 62, the temperature sensor 56 in the supply passage 14 is deemed to be abnormal. For example, if the water temperature measured by the temperature sensor 56 in the supply passage 14 is within a predetermined range that includes the temperature of the air supply source, the temperature sensor 56 can be deemed to be normal; otherwise, it can be deemed to be abnormal. In some embodiments, if an abnormality is determined, a warning light or buzzer can be used to alert the operator. The abnormality detection method described above is particularly advantageous when the temperature sensor 62 in the supply source has already been installed for another purpose and the control device 54 is configured to receive the data. In other embodiments, gases other than air can be used as needed.

[0018] [Salinity control of breeding water] 5 and 6 show yet another embodiment of a pump system 70 for supplying rearing water (salt water such as artificial seawater) to the aquarium 12 while monitoring its salinity when cultivating marine fish and shellfish in the aquarium 12. In this embodiment, a saltwater supply source (not shown) is connected upstream of the supply passage 14. Furthermore, a salinity sensor 76 is provided instead of the pressure sensor 38 and temperature sensor 56 of the above embodiment. The control device 74 constantly or periodically measures the salinity of the rearing water flowing through the discharge passage 20 using the salinity sensor 76, and if the measured salinity significantly deviates from a set target concentration, the control device 74 determines that the salinity of the rearing water being supplied is normal. For example, if the measured salinity is within a predetermined range including the target concentration, the salinity of the rearing water being supplied can be determined to be normal; otherwise, it can be determined to be abnormal. If an abnormality is determined, the control device adjusts the salinity of the rearing water being drawn in through the intake passage 18.

[0019] [Detection of abnormality in the salt concentration sensor] An intake passage 72 for introducing fresh water (water with a salinity close to zero) joins the supply passage 14 upstream of the pump 16. The upstream side of the intake passage 72 is connected to a fresh water source (not shown). For example, this source may be a hydroponic cultivation system installed near the aquarium 12. A separate salinity sensor (not shown) is provided to measure the salinity of the fresh water at the supply source. A three-way valve 32 is provided at the joining point of the fresh water intake passage 72, allowing either one of the two intake passages 18, 72 to be selectively connected to the pump 16.

[0020] To detect an abnormality in the salinity sensor 76, first, as shown in FIG. 6 , the three-way valve 32 is switched to connect the freshwater intake passage 72 to the pump 16, and freshwater is introduced into the discharge passage 20 (arrow 78). After a certain amount of time has passed, the freshwater begins to leak over the stop valve 34 into the aquarium 12 (arrow 80). After a predetermined time has passed, which is the time required for the freshwater to leak into the aquarium 12, the pump 16 is stopped and the stop valve 34 is closed. If necessary, the three-way valve 32 is also fully closed. This fills the supply passage 14 downstream of the three-way valve 32 with the freshwater. The salinity of the freshwater is measured by the salinity sensor 76 in the supply passage 14. If the measured salinity significantly deviates from the salinity of the freshwater source measured by another salinity sensor (a value close to zero), the salinity sensor 76 in the supply passage 14 is deemed to be abnormal. For example, if the salinity measured by the salinity sensor 76 in the supply passage 14 is within a predetermined range that includes the salinity of the supply source, the salinity sensor 76 can be considered normal; otherwise, it can be considered abnormal. Depending on the embodiment, if an abnormality is determined, a warning light or buzzer can be used to alert the operator. The abnormality detection method described above is particularly advantageous when a separate salinity sensor (not shown) has already been installed in the supply source for another purpose, such as when the freshwater supply source is the hydroponic cultivation system described above, and the control device 74 is configured to receive that data. In another embodiment, instead of freshwater, low-salinity water (e.g., brackish water) with a lower salinity than the culture water can be used.

[0021] When the supply of rearing water is stopped, the inside of the pump 16 and the inside of the supply passage 14 from the three-way valve 32 to the stop valve 34 can be filled with fresh water or low-concentration salt water, just as in the case where air is used as described above. In this way, corrosion of the inside of the pump 16 and piping caused by high concentrations of salt can be suppressed compared to when the pump 16 is simply stopped while the rearing water is being supplied.

[0022] [Other embodiments] As shown in FIG. 7 , in another embodiment, the flow rate control and temperature / salinity monitoring described above can be performed by a single pump system 90. Specifically, a pressure sensor 38 (or flow rate sensor), a temperature sensor 56, and a salinity sensor 76 are all provided in the discharge passage 20. Furthermore, upstream of the pump 16, both the intake passage 30 for gases such as air and the intake passage 72 for freshwater or low-salinity water are joined in the culture water supply passage 14. Instead of a three-way valve, a single selector valve 96 or a combination of multiple selector valves is used, which can selectively connect one of the intake passages 18, 30, or 72 to the pump 16. This allows air or freshwater to be selectively introduced into the discharge passage 20, as indicated by arrows 40 and 78. This pump system 90 can also evaluate the flow rate characteristics of the pump 16 and detect abnormalities in the temperature and salinity sensors. The methods for doing this are substantially similar to those described above with reference to FIGS. 1 to 6 , and all can be performed by a single control device 94.

[0023] In other embodiments, in addition to the aquarium 12 for cultivating fish and shellfish, it can also be used as a variety of breeding tanks, cultivation tanks, and culture tanks for edible, ornamental, or exhibited organisms. For example, it can be used as an aquarium (nutrient solution tank) or tray for hydroponic cultivation of plants, or as an aquarium (wet mud tank) that replicates an artificial tidal flat for cultivating benthic organisms such as crustaceans and shellfish. In the case of hydroponic cultivation, the above-mentioned breeding water can be replaced with, for example, an aqueous solution (nutrient solution) in which nutrients are dissolved.

[0024] In another embodiment, the pump can be used to draw water from aquaculture or hydroponic tanks into a storage tank or an adjustment tank. In yet another embodiment, the pump can be used to add water to an adjustment tank to make wet mud collected from a tidal flat tank reusable. In yet another embodiment, the pump can be used to move water between a tidal flat tank and an adjustment tank to simulate the ebb and flow of the tides. In this case, the pump can be a bidirectional pump, and air intake passages can be connected to both sides of the pump as needed.

[0025] In another embodiment, the second fluid may be any fluid having a lower density than the first fluid. Even in this case, power consumption can be reduced by evaluating the flow characteristics using the second fluid. In some cases, both the first and second fluids may be gases.

[0026] Although various specific embodiments have been described above, the technology disclosed in the present application is not limited to these embodiments, and a person skilled in the art can make various substitutions, improvements, and modifications without departing from the purpose of the present technology. [Explanation of symbols]

[0027] 10. Pump System 12 Aquarium 14 Water supply passage 16 Pump 18 Water intake passage 20 Discharge passage 22 Control device 24 Flow of breeding water 30 Air intake passage 32 Three-way valve 34 Shut-off valve 36 Discharge passage from the water tank 38 Pressure Sensor 40 Air flow through the pump 42 Air flow into the tank 50 Pump System 54 Control device 56 Discharge passage temperature sensor 62 Temperature sensor of the supply 70 Pump System 72 Freshwater intake passage 74 Control Device 76 Salinity sensor 78 Freshwater flow through a pump 80 Flow of freshwater into the aquarium 90 Pump System 94 Control Device 96 Switching valve

Claims

1. 1. A fluid pump system comprising: A pump and a first intake passage for introducing a first fluid into the pump; at least one second intake passage for introducing a second fluid having a lower specific gravity than the first fluid into the pump; a discharge passage for discharging fluid from the pump; at least one switching valve configured to selectively connect one of the first suction passage and the second suction passage to the pump; a state quantity sensor that measures a state quantity of the second fluid and is disposed in the discharge passage to measure a flow rate; and a control device, the control device comprising: When the first fluid is pumped, the first suction passage is connected to the pump by the switching valve; operating the pump to cause a first fluid to flow into the discharge passage; When evaluating the flow rate characteristics of the pump, the second suction passage is connected to the pump by the switching valve; operating the pump to cause the second fluid to flow into the discharge passage; measuring a flow rate of the second fluid using the state quantity sensor; The fluid pump system is configured to evaluate the flow characteristics of the pump when pumping the first fluid based on the flow rate of the second fluid.

2. 2. The fluid pump system of claim 1, the state quantity sensor is a pressure sensor, a shutoff valve disposed in the discharge passage; the control device closes the shutoff valve when the discharge passage is filled with the second fluid; activating the pump to further cause the second fluid to flow into the discharge passage; measuring a pressure increase of the second fluid in the discharge passage using the pressure sensor; The fluid pump system is configured to determine a flow rate of the second fluid based on the pressure increase.

3. 2. The fluid pump system of claim 1, the state quantity sensor is a flow rate sensor, The fluid pump system, wherein the controller is configured to measure the flow rate of the second fluid with the flow sensor.

4. The fluid pump system according to any one of claims 1 to 3, The control device stores the previously evaluated flow rate characteristics of the pump, the switching valve connects the first suction passage to the pump; A fluid pumping system configured to pump a first fluid by operating the pump based on the stored flow characteristics.

5. The fluid pump system according to any one of claims 1 to 4, the first fluid is a liquid and the second fluid is a gas; a temperature sensor disposed in the discharge passage; The control device the switching valve connects the second intake passage to the pump; The pump is operated to cause gas to flow into the discharge passage; measuring the temperature of the gas with the temperature sensor; A fluid pump system configured to determine whether or not the temperature sensor is abnormal based on the measured temperature of the gas.

6. 6. The fluid pump system of claim 5, the second fluid is air in an environment in which the fluid pump system is installed; The control device is configured to determine whether or not there is an abnormality in the temperature sensor by comparing the air temperature measured by the temperature sensor with an environmental temperature measured separately.

7. The fluid pump system according to any one of claims 1 to 6, the first fluid is saltwater having a first concentration; the second fluid is low-concentration saltwater or freshwater having a second concentration less than the first concentration; a salinity sensor disposed in the discharge passage; The control device the switching valve connects the second intake passage to the pump; By operating the pump, low-concentration salt water or fresh water is introduced into the discharge passage; The salinity of the low-concentration saltwater or freshwater is measured by the salinity sensor; A fluid pump system configured to determine whether or not there is an abnormality in the salinity sensor based on the measured salinity concentration.

8. The fluid pump system according to any one of claims 1 to 7, a shutoff valve disposed in the discharge passage; The control device the switching valve connects the second intake passage to the pump; operating the pump to cause the second fluid to flow into the discharge passage; stopping the pump with the inside of the pump filled with the second fluid; The fluid pump system is configured to close the closure valve.

9. The fluid pump system according to any one of claims 1 to 8, the discharge passage is connected to a water tank or a wet mud tank for raising living organisms; The fluid pump system wherein the first fluid is an aqueous solution for supplying the water tank or wet mud tank.

Images