JP7746194B2 - Fluid Pump System - Google Patents

Description

The technology disclosed in this application relates to a fluid pump system.

When using an electric pump to transport 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, 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 and evaluate the pump's flow rate characteristics as needed. 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 pump discharge pressure while pumping a fluid.

Japanese Patent Application Publication No. 06-066287

The system described in the above publication is based on the premise that flow rate is measured during normal operation. Therefore, if one wishes to evaluate the flow rate characteristics of a pump using the measurement technology described in the above publication, it is necessary to pump fluid just for the evaluation, even when there is no need to pump fluid with the pump, which increases power consumption, creating an issue. Therefore, it is desirable to be able to evaluate the flow rate characteristics of a pump while minimizing power consumption.

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 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 the 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 allow the first fluid to flow into the discharge passage. When evaluating the 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 allow 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.

FIG. 1 is a diagram showing the configuration of a pump system for supplying breeding water to an aquarium as one embodiment. 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. 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. 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. 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. 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. 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.

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 repeated descriptions will be omitted.

[Pump system]
1 and 2 show, as one embodiment, a pump system 10 for supplying culture water to an aquarium 12 for cultivating fish and shellfish. A supply passage 14 for passing 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).

[Flow Control]
The flow rate of the electric pump is controlled, for example, by varying the power applied 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 (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 device (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 transmit 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.

[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 the 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. The discharge passage 20 is also provided with a stop valve 34 that can close communication. 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.

To evaluate the pump's flow characteristics, first, as shown in Figure 2, the three-way valve 32 is switched to connect the air intake passage 30 to the pump 16, and air is introduced from the atmosphere 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 temporarily stopped and the shut-off valve 34 is closed. This fills the supply passage 14 downstream from 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 from atmospheric pressure is measured using 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 air flow rate Q 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, one embodiment uses the specific gravity (density ratio) of the rearing water relative to air at atmospheric pressure. 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.

Such evaluation of flow characteristics can be performed, for example, during the initial operation of the pump system 10, to understand or learn the unique flow characteristics (due to product variations) of the pump 16 being used. Furthermore, even after the initial operation, flow characteristics can be evaluated periodically or on a one-off basis to track changes in the system over time 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, it is possible that rearing water is being supplied when a specified period of time has elapsed. In this case, the supply of rearing water may be interrupted before proceeding with the evaluation of flow characteristics, or evaluation may be performed after waiting for the supply of rearing water to be stopped. In another embodiment, the evaluated flow characteristics can also be used to detect abnormalities such as deterioration or failure of the pump 16.

In another embodiment, not shown, a flow 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; if the shut-off valve 34 is present, 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.

[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.

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.

[Temperature control of 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 above 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 water being supplied is considered normal; otherwise, it is considered abnormal. If an abnormality is determined, the temperature of the water being drawn in through the intake passage 18 is adjusted.

[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 temperature of the air. 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.

[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 control device 74 determines that the salinity of the rearing water being supplied is normal, and otherwise determines that the salinity is abnormal. If an abnormality is determined, the control device 74 adjusts the salinity of the rearing water being drawn in through the intake passage 18.

[Detection of abnormalities in the salinity sensor]
An intake passage 72 for introducing freshwater (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 freshwater supply source (not shown). For example, this supply 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 freshwater supply source. A three-way valve 32 is provided at the joining point of the freshwater intake passage 72, allowing either one of the two intake passages 18, 72 to be selectively connected to the pump 16.

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 shut-off 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 shut-off valve 34 is closed. If necessary, the three-way valve 32 is also fully closed. This fills the supply passage 14 downstream from the three-way valve 32 with the freshwater. The salinity of the freshwater is then 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, low-salinity water (e.g., brackish water) with a lower salinity than the breeding water can be used instead of freshwater.

When the supply of rearing water is stopped, just as in the case of using air described above, the inside of the pump 16 and the inside of the supply passage 14 from the three-way valve 32 to the shut-off valve 34 can be filled with freshwater or low-concentration saltwater. This can reduce corrosion of the pump 16 and the inside of the piping caused by high concentrations of salt, compared to simply stopping the pump 16 while the rearing water is being supplied.

[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 air or other gas intake passage 30 and the freshwater or low-salinity water intake passage 72 join the rearing water supply passage 14. Instead of a three-way valve, a single selector valve 96 or a combination of multiple selector valves is used that can selectively connect one of these 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.

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 recreates 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) with dissolved nutrients.

In another embodiment, it can be used to draw water from aquaculture or hydroponic tanks into a storage tank or adjustment layer. In yet another embodiment, it 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, it can be used to move water between a tank and an adjustment tank to recreate the ebb and flow of the tides on a tidal flat. In this case, the pump can be a type that can pump pressure in both directions, and air intake passages can be connected to both sides of the pump if necessary.

In another embodiment, the second fluid can be any fluid with 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.

Although various specific embodiments have been described above, the technology disclosed in this application is not limited to these embodiments, and those skilled in the art may make various substitutions, improvements, and modifications without departing from the scope of the technology.

10 Pump system 12 Aquarium 14 Breeding water supply passage 16 Pump 18 Breeding water intake passage 20 Discharge passage 22 Control device 24 Breeding water flow 30 Air intake passage 32 Three-way valve 34 Shut-off valve 36 Discharge passage from aquarium 38 Pressure sensor 40 Air flow through the pump 42 Air flow into aquarium 50 Pump system 54 Control device 56 Discharge passage temperature sensor 62 Supply source temperature sensor 70 Pump system 72 Freshwater intake passage 74 Control device 76 Salinity sensor 78 Freshwater flow through the pump 80 Freshwater flow into aquarium 90 Pump system 94 Control device 96 Switching valve

Claims (9)

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. 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. 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. 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. 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. 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. 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. 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. 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.