PUMP WITH RUN-DRY PREVENTION FOR USE ON BOARD A WATERCRAFT

Abstract

The present disclosure relates to a pump system including a pump and a liquid detection sensor or a flow sensor for sensing liquid presence or liquid flow. The water pump system also includes a controller that interfaces with the liquid detection sensor or flow sensor and uses data from the liquid detection sensor or the flow sensor to prevent the pump from being damaged under a run-dry condition.

Description

TECHNICAL FIELD

The present disclosure relates generally to pumps such as seawater pumps that can be used on an on-board water system of a watercraft.

BACKGROUND

Watercraft, particularly marine watercraft, often include on-board water systems which use water (e.g., sea water) drawn from the bodies of water on which the watercraft are buoyantly supported. A prevalent type of on-board water system is configured to pass drawn water through a heat exchanger used to cool refrigerant associated with air conditioning systems, chillers, and the like. Other on-board water systems include potable water systems, sanitation systems, propulsion systems, engine cooling systems, bait-well filling systems and systems corresponding to ancillary equipment. Pumps are used to move water through the on-board water systems. Such pumps can be prone to rapid failure due to overheating under conditions in which the pumps are run when lacking sufficient water to provide cooling.

SUMMARY

One aspect of the present disclosure relates to a water pump system including a water pump and a sensor for detecting the presence of water in the pump. The water pump system also includes a controller that interfaces with the sensor and prevents power from being supplied to the water pump under conditions in which a condition of insufficient water in the pump is detected by the sensor.

Another aspect of the present disclosure relates to a water pump system including a pump and a water detection sensor mounted to the pump for detecting the presence of water within the pump. The water pump system also includes a controller that interfaces with the water detection sensor and prevents power from being provided to a motor of the pump when the water detection sensor indicates insufficient water within the pump.

Another aspect of the present disclosure relates to a pump system including a liquid pump and a flow sensor for detecting the existence of flow when the pump is initiated. The pump system also includes a controller that interfaces with the flow sensor and stops power from being supplied to the pump if the flow sensor provides a reading indicative of a condition of insufficient liquid in the pump. The flow sensor can be a switch type sensor which simply provides a reading of flow or no flow at a location along a flow path through which the pump is adapted to cause flow when operating normally. Alternatively, the flow sensor can be configured to sense a flow rate or flow speed at the location of the flow path. The location can be at the pump or away from the pump at a location which is normally in fluid communication with the pump.

A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the examples described herein are based.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate aspects of the present disclosure and together with the description, serve to explain the principles of the disclosure. A brief description of the drawings is as follows:

FIG. 1 illustrates a watercraft including an on-board water system incorporating a water pump system in accordance with the principles of the present disclosure;

FIG. 2 is a schematic view of a water pump system that can be used with the on-board water system of FIG. 1;

FIG. 3 is a cross-sectional view of an example pump in accordance with the principles of the present disclosure having a water detection sensor such a conductivity sensor;

FIG. 4 is a cross-sectional view of an example pump in accordance with the principles of the present disclosure having a water detection sensor such an ultrasonic sensor;

FIG. 5 is a perspective view of another pump that can be equipped with a water detection sensor in accordance with the principles of the present disclosure;

FIG. 6 is an exploded view of the pump of FIG. 5;

FIG. 7 is a longitudinal cross-sectional view of the pump of FIG. 5 cut through the central drive shaft;

FIG. 8 is a transverse cross-sectional view of the pump of FIG. 5 cut through the outlet; and

FIG. 9 is a schematic view of a system in accordance with the principles of the present disclosure depicting example locations at which sensing devices such as flow sensors and/or water liquid detection sensors can be installed.

DETAILED DESCRIPTION

FIG. 1 illustrates a watercraft 20 having an on-board water system 22 including a pumping system in accordance with the principles of the present disclosure. The watercraft 20 is shown supported on a body of water 26. The on-board water system 22 includes an inlet 28, an outlet 30, and a water flow path 32 that extends from the inlet 28 through the watercraft 20 to the outlet 30. The inlet 28 is configured for drawing water from the body of water 26 into the water flow path 32. The inlet 28 is located below a water line 34 of the watercraft 20 and is preferably located at a bottom of the hull of the watercraft 20. The inlet 28 can be opened and closed by a valve 36 such as a seacock. The outlet 30 is configured for discharging water that has passed through the water flow path 32 back to the body of water 26. Preferably, the outlet 30 is positioned above the water line 34. The on-board water system 22 can include a plurality of components positioned along the water flow path 32. The water flow path 32 can include a plurality of conduits 38 (e.g., hoses, tubes, pipes, etc.) which extend between the components of the on-board water system 22 and function to carry water along the water flow path 32 between the various components. As shown at FIG. 1, the depicted components include a flow-through housing 39 enclosing water strainer 40, a pump 42, and one or more systems and/or equipment 44 that make use of water conveyed through the water flow path 32.

In the depicted example, an electrolytic cell 46 is integrated with the housing 39 within the strainer 40. The electrolytic cell 46 interfaces with a control unit 48 (e.g., controller) and is adapted for generating a biocide (e.g., chlorine or a chlorine derivative) within the water of the water flow path 32 while the water passes through the housing 39. The biocide is configured for inhibiting biofouling within the conduits 38 and within one or more of the components positioned along the water flow path 32. It will be appreciated that the biocide can also be referred to as a disinfecting agent or a cleaning agent since the biocide can also include disinfecting and cleaning properties. Further details about electrolytic cells that can be used in the water system are disclosed by PCT International Publication Number WO 2019/070877, which is hereby incorporated by reference in its entirety.

It will be appreciated that examples of the type of the systems and/or equipment 44 can include cooling systems such as air conditioners or chillers where water drawn from the body of water 26 can be used as a cooling media for cooling refrigerant of the cooling systems (e.g., within a heat exchanger or heat exchangers). In other examples, the water from the water flow path 32 can be used to provide engine cooling. In other examples, water from the water flow path 32 can be used for sanitation systems or watercraft propulsion systems. Example water systems can also include potable water systems 33 for providing drinking water (drinking water systems often include reverse osmosis filtration systems), shower water, water for faucets, or other potable water uses on the water vessel. Additionally, water from the water flow path 32 can be used for live well systems to fill live wells for holding bait on the watercraft 20. In certain examples, the electrolytic cell 46 can be deactivated when water is directed to the water systems 33.

FIG. 2 depicts a pumping system 100 in accordance with the principles of the present disclosure. A preferred application is for pumping applications related to the pumping of water (e.g., salt water (e.g., sea water) or fresh water) through on-board water systems of watercraft. For example, the pumping system 100 can be integrated into the on-board water system 22 of FIG. 1. However, the pumping system is not limited to onboard marine applications, and can be used in any pumping application where run-dry scenarios are a possible concern.

Referring to FIG. 2, the pumping system 100 includes the pump 42, a controller 102, indicators 103 and/or buttons 104 that interface with the controller 102, an alternating current (AC)-to-direct current (DC) power supply 106 (an AC/DC power supply), a power relay 182 and a water detection sensor 107. The AC/DC power supply 106 and the power relay 182 are electrically isolated from the controller 102 and the water detection sensor 107 (e.g., the controller has a separate floating ground). The pump 42 is depicted as a magnetic drive pump having an electric motor 108 and a magnetic coupler 110 for transferring torque from the electric motor 108 to an impeller 112 of the pump 42. The magnetic coupler 110 allows for mechanical isolation between the electric motor 108 and the impeller 112. The pump 42 can include a housing 114 for enclosing the impeller 112. The water detection sensor 107 can be mounted to the pump housing 114 and can be configured for detecting whether water is present within the interior of the housing 114. In certain examples, the water detection sensor 107 can be positioned to detect whether the impeller and related impeller components are immersed in water such that water is available to provide cooling of the pump 42 during pump operation. In certain examples, the water detection sensor 107 can be mounted in the general vicinity of the impeller 112. In certain examples, the water detection sensor 107 can be positioned adjacent an outlet of the pump 42 (e.g., in an outlet port of the pump). In certain examples, the water detection sensor 107 can be positioned to determine if the pump 42 is at least one-third full of water or at least one-half full of water when the pump is not running and the water is positioned by gravity. The water detection sensor 107 can be mounted at other locations of the pump 42 (e.g., in an internal water chamber, in the impeller chamber, in a chamber corresponding to the magnetic coupling, etc.). In certain examples, the water detection sensor 107 can be positioned to determine whether a bearing or bearings corresponding to an impeller shaft are immersed in water when the pump is not running or before the pump is activated and the water is positioned by gravity. The water detection sensor 107 can also be mounted in the water flow path of the pump 42 (e.g., a fitting or other housing containing the water detection sensor 107 can be installed as part of the flow path through which the pump is adapted to cause flow at a location upstream or downstream of the pump 42) preferably at a location at the same level or higher than the impeller shaft bearings of the pump.

It will be appreciated that certain operations can cause air to be present in the water flow path 32. For example, when the strainer 40 is emptied, it is often needed to bleed air from the system before re-starting the system. If air is not bled from the system, air can occupy the pump. If the pump is operated under this type of condition (e.g., a dry or low water condition), the pump can quickly overheat and be damaged. Aspects of the present disclosure relate to water sensing arrangements and pump control systems that prevent the pump from being started under conditions in which the pump lacks sufficient water for cooling; or for preventing the pump from running under such conditions for a duration at which pump damage can occur.

FIG. 3 is a schematic cross-sectional view of an example configuration for the pump 42. The housing 114 defines an inlet 120 and an outlet 122. A flow path 124 is defined within the housing 114 between the inlet 120 and the outlet 122. As depicted, the pump is a centrifugal pump and the impeller 112 is configured to pump water through the flow path 124 from the inlet 122 the outlet 122 through centrifugal action. The impeller 112 includes a main impeller pump head 126 positioned within the flow path 124, a shaft 128 that extends through a wall 130 of the housing 114 and a magnetic drive head 132. The magnetic drive head 132 and a portion of the shaft 128 are positioned within a water chamber 134 located on an opposite side of the wall 130 from the flow path 124. The magnetic drive head 132, the shaft 128 and the main impeller pump head 126 are configured to rotate in unison with one another about an axis of rotation 136 of the impeller 112. The water chamber 134 is defined in part by a containment shell 138 coupled to the wall 130. The motor 108 includes a driveshaft 140 having a magnetic coupling 142 that surrounds the magnetic drive head 132 outside the containment shell 138. Torque is magnetically transmitted from the magnetic coupling 142 to the magnetic drive head 132 through the containment shell 138. Thus, the motor 108 is mechanically isolated from the magnetic drive head 132 while still being able to transfer torque thereto. A bearing 144 is provided for facilitating rotation of the impeller 112 relative to the wall 130. When water is present in the pump, the water chamber 134 remains filled with water and provides cooling of the impeller and the housing components. If the pump runs without water, the water chamber 134 drains of water and the rotation interfaces can quickly overheat thereby causing pump damage (e.g., melting of plastic parts, particularly adjacent the magnetic interface). Melting or other part damage can be particularly rapid in composite parts having both plastic and metal components, where the plastic can be prone to melting if cooling water is not present.

In certain examples, the pump housing 114 primarily has a plastic construction. As depicted, the bearing 144 supporting the shaft 128 of the impeller 112 is a bushing that supports the shaft 128 while allowing rotation of the shaft 128 relative to the pump housing 114. The shaft 128 can have a ceramic or metal construction. As depicted, the pump housing 114 includes a bearing support sleeve 115 in which the bearing 144 is supported by the pump housing 114. During normal operation of the pump 42, the bearing 144 is exposed to liquid within the pump 42 (e.g., the water being pumped through the flow path 124 and that occupies the water chamber 134) such that the bearing 144 is bathed in liquid (e.g., water) to provide cooling of the shaft-to-bearing interface during rotation of the shaft 128. In cases in which the pump 42 is started and the shaft 128 rotates relative to the bearing 144 while the bearing 144 is not exposed to water for cooling, the bearing 144 quickly increases in temperature which can cause melting of adjacent plastic portions of the pump housing 114 (e.g., the bearing support sleeve 115) thereby damaging the pump.

The water detection sensor 107 is configured to interface with the controller 102 thereby allowing the controller to interpret water sensing data generated by the water detection sensor 107. In certain examples, the water detection sensor 107 can communicate with the controller 102 by sending water sense signals (e.g., voltage readings, frequencies, current readings, resistance readings, etc.) to the controller 102 either by a wire or through wireless transmissions. As depicted at FIG. 3, the water detection sensor 107 can include an electrical conductivity sensor 107a mounted within a port 150 defined by the housing 114. In one example, the port 150 can be located at an outlet side of the flow path 124 (e.g., at the outlet of the pump). The electrical conductivity sensor 107a can include electrically conductive probes 152 that project into the interior of the housing (e.g., into the flow path). Electrical conductivity can be measured between the probes 152. When the probes 152 are immersed in water (particularly salt water but also fresh water), the conductivity between the probes is substantially higher than when the probes are separated by air (which would occur when insufficient water is present in the flow path). Thus, a reading of relatively high conductivity provides an indication to the controller 102 that sufficient water is present in the pump, while a reading of relatively low conductivity provides an indication to the controller 102 that the probes are separated by air and that insufficient water is present in the pump.

As depicted at FIG. 4, the water detection sensor 107 can include an ultrasonic sensing arrangement 107b mounted within a wall of the housing 114. In one example, the ultrasonic sensing arrangement 107b can be located at an outlet side of the flow path 124 (e.g., water sensing is provided at the outlet of the pump). The ultrasonic sensing arrangement 107b can include piezo-electric sensors 160 each including piezo-electric crystals. The sensors 160 can be mounted within pockets defined with the housing 114. In a preferred example, the sensors 160 do not need to be positioned in communication with the interior of the pump and can act through a wall of the pump (i.e., the ultrasonic signals can pass through the wall of the pump). The sensors 160 are thus isolated from contact with the water being pumped through the pump by portions of the pump walls. This is advantageous since potential leak points are eliminated and less sealing is required. The sensors 160 can be positioned on opposite sides of the flow path in opposition with respect to one another and the sensors 160 can be configured such that an ultrasonic signal generated by one of the sensors travels through the flow path and is received by the other of the sensors 160. It will be appreciated that water is a better medium for carrying ultrasonic signals than air to the extent that ultrasonic signals travel significantly faster through water than air. Thus, when water is positioned in the flow path between the sensors 160 and an ultrasonic signal is transmitted across the flow path by one of the sensors 160, the travel time of the signal received by the opposing sensor 160 is relatively low as compared to when air is present in the flow path between the sensors 160. Thus, a reading of relatively low ultrasonic signal travel time provides an indication to the controller 102 that sufficient water is present in the pump, while a reading of relatively high ultrasonic signal travel time provides an indication to the controller 102 that the sensors 160 are separated by air and that insufficient water is present in the pump.

In still other embodiments, the water detection sensor can include a magnetic/inductive sensor where a characteristic of a magnetic field generated by the sensor varies depending upon whether air or water is present adjacent the sensor. In certain examples, water detection sensors in accordance with the present disclosure can detect when insufficient water is in the pump by detecting the presence of air in the pump.

The electric motor 108 of the pump 42, the controller 102, the water detection sensor 107 and the indicators 103 are all powered by a common power source 170 (e.g., an alternating current (AC) power source of the boat such as an electrical generator or mains electricity when the boat is docked). A pump control 180 (e.g., a boat pump control) can interface with components of the on-board water system 22. When there is a demand for water by one or more of the components of the on-board water system 22, the pump control 180 electrically connects (e.g., via relay 181) the power source 170 to the controller 102 and to the power relay 182 (e.g., a switch) which is controlled by the controller 102. The power relay 182 prevents power from the power source 170 from being connected to the electric motor 108 until after the controller 102 determines (e.g., via input from the water detection sensor 107) that sufficient water is present in the pump for proper pump operation. The AC/DC power supply 106 converts the AC power from the power source 170 to DC power which is provided to the controller 102. The pump control 180 can also send a signal to the controller 102 indicating that a demand for water has been requested by the on-board water system 22. Upon indication from the pump control 180 that a demand for water has been requested, the controller 102 determines whether the pump 42 has sufficient water to operate properly based on input (e.g., one or more water sense signals) provided by the water detection sensor 107. If the input from the water detection sensor 107 indicates that sufficient water is present in the pump 42, the controller 102 closes the power relay 182 such that the motor 108 of the pump 42 is provided power through the relay 182 from the power source 170. Concurrently, the controller 102 can cause one of the indicators 103 (e.g., a light such as an LED) to provide an indication that the pump 42 has been activated. In contrast, if the input from the water detection sensor 107 indicates a lack of water within the pump 42, the controller 102 maintains the power relay 102 in an open state such that power from the power source 170 is prevented from being provided to the motor 108 of the pump 42. Concurrently, the controller 102 can cause one of the indicators 103 (e.g., a light such as an LED) to provide an indication that the pump lacks sufficient water to be activated.

In certain examples, the controller 102 can include a processor that can interface with the water detection sensor 107, the power relay 182, indicators 103, buttons 104 and the boat pump control 180. The processor can interface with software, firmware, and/or hardware. Additionally, the processor can include digital or analog processing capabilities and can interface with memory (e.g., random access memory, read-only memory, or other data storage). In certain examples, the processor can include a programmable logic controller, one or more microprocessors, or like structures. Example user interfaces can include one or more input structures such as keyboards, touch screens, buttons, dials, toggles, or other control elements that can be manipulated by an operator to allow the operator to input commands, data, or other information to the controller. The display can include lights, audible alarms, screens, or other display features.

FIGS. 5-8 depict an alternative pump 242 usable with the pumping system 100 of FIG. 2. The pump 242 is a centrifugal pump; but other pump styles could also be used in the pumping system 100. The pump includes a motor 208 (e.g., an electric motor) having a drive shaft 209 that drives rotation of a magnetic drive housing 210 supporting a plurality of magnets 211. The magnets 211 are supported by the magnetic drive housing 210 circumferentially about an axis of rotation 212 of the drive shaft 209 and the drive housing 210. The magnets 211 are supported to face radially toward the axis of rotation 212. A mechanical torque transmitting connection is provided between the drive housing 210 and the drive shaft 209 (e.g., a keyed connection; a splined connection; a connection with opposing flats such as a hexagonal interface, etc.). The magnets 211 of the magnetic drive housing 210 are adapted to be magnetically coupled with magnets 213 of a magnet arrangement 214 corresponding to an impeller 215 of the pump 242. The magnet arrangement 214 includes a magnet support body 216 that supports the magnets 213 circumferentially about the axis of rotation 212 with the magnets 213 facing radially away from the axis of rotation 212 and in opposition with respect to the magnets 211 of the magnetic drive housing 210. The magnets 211, 213 provide a magnetic coupling between the magnetic drive housing 210 and the magnet arrangement 214 that allows torque to be magnetically transferred from the magnetic drive housing 210 to the magnet arrangement 214. The magnet support body 216 couples with the impeller 215 (e.g., interlocks with the impeller 215) such that the magnet support body 216 and the impeller 215 are adapted to rotate together in unison about the axis of rotation 212. The magnet support body 216 rotationally mounts on an impeller shaft 218 aligned along the axis of rotation 212. A bearing 219 (e.g., a bushing) is provided between the magnet support body 216 and the impeller shaft 218 for supporting rotation of the magnet support body 216 and the impeller 215 about the impeller shaft 218.

The pump 242 includes an inlet 244 and an outlet 246. As depicted, the inlet 244 is an axial inlet having an axis that aligns with the axis of rotation 212 and the outlet 246 is a radial outlet having an axis that is radially oriented relative to the axis of rotation 212. The inlet 244 and the outlet 246 are defined by a main housing body 248 having a polymeric construction (e.g., molded plastic). The main housing body 248 also defines a pump chamber 250 in which the impeller 215 rotates to pump liquid (e.g., water) from the inlet 244 to the outlet 246. Rotation of the impeller 215 is driven by torque from the electric motor 208 which is transferred to the impeller 215 through the magnetic coupling.

A containment shell 252 attaches to the main housing body 248 in a sealed manner (e.g., via a gasket such as seal 254) to seal the pump chamber 250 and block fluid communication between the magnetic drive housing 210 and the pump chamber 250. In this way, the electric motor 208 and the magnetic drive housing 210 are not exposed to the liquid being pumped through the pump 242. The impeller shaft 218, the bearing 219, the impeller 215 and the magnet arrangement 214 are all within the pump chamber 250 and exposed to liquid within the pump chamber 250 that is being pumped through the pump chamber 250 by the impeller 215. The liquid being pumped thereby provides cooling for the parts within the pump chamber 250. The magnet arrangement 214 fits within a sleeve 220 defined by the containment shell 252. The sleeve 220 separates (e.g., mechanically isolates) the magnet arrangement 214 from the magnetic drive housing 210 to prevent liquid from the pump chamber 250 from contacting the electric motor 208 and magnetic drive housing 210; but allows the magnetic coupling of the magnet arrangement 214 and the magnetic drive housing 210 such that torque from the electric motor 208 can be transferred through the magnetic coupling to drive rotation of the magnet arrangement 214 and the impeller 215 about the impeller shaft 218 within the pump chamber 250. A thrust bearing 260 provides a rotational interface between the impeller 215 and the interior of the main housing body 248 to prevent contact between the impeller 215 and the main housing body 248. Opposite ends of the thrust bearing 260 can fit within pockets defined by the main housing body 248 and the impeller 215.

An outer housing 262 of the pump 242 includes the main housing body 248 and a cover 262 that attaches to the main housing body 248 and covers the containment shell 252. A gasket 261 can provide sealing between the cover 262 and the containment shell 252. The cover 262 includes a central opening 264 through which the sleeve 220 extends. The sleeve 220 extends through the opening 264 beyond the cover 262 such that the magnetic drive housing 210 can fit over the sleeve 220 without interference from the cover 262. An outer connection sleeve 265 connects between the cover 262 and a motor housing 266 of the electric motor 208. The outer connection sleeve 265 covers the magnetic drive housing 210 and opposite ends of the sleeve 264 can be sealed (e.g., with gaskets such as o-rings) with respect to the cover 262 and the motor housing 266.

Opposite ends of the impeller shaft 218 are supported by the main housing body 248 and the containment shell 252. For example, the main housing body 248 includes a support structure including legs 267 extending from the inlet and a sleeve 268 for supporting one end of the impeller shaft 218 and the containment shell 252 includes a support structure including a sleeve 269 for supporting the opposite end of the impeller shaft 218. The main housing body 248, the legs 267, the sleeve 268, the containment shell 252, the sleeve 269, and the magnetic support body 216 can all have a polymeric (e.g., plastic) construction. The impeller shaft 218 can have a metal or ceramic construction. In cases where the pump 242 runs dry for an extended period, the impeller shaft 218, the bearing 219 and the bearing 260 are not bathed in liquid which provides cooling; and can quickly overheat. Such overheating can cause damage (e.g., melting, plastic deformation, etc.) of the adjacent plastic parts such as portions of the main housing body 248, the legs 267, the sleeve 268, the containment shell 252, the sleeve 269, and the magnetic support body 216. Thus, it is preferred for the pump 242 to be used in a system having a liquid detection sensor (e.g., sensors 107a, 107b) for detecting whether sufficient liquid (e.g., water) is in the pump 242 for the pump to operate properly such that heat sensitive parts are bathed in liquid for cooling. In certain examples, the liquid detection sensor is mounted adjacent the outlet of the pump 242 or elsewhere in the pump as described above with respect to the pump 42. FIG. 8 shows a liquid detection sensor 107 mounted at the outlet 246.

FIG. 9 depicts another pumping system 300 (e.g., a water pumping system) in accordance with the principles of the present disclosure. The system includes a flow path 332 that extends between an inlet 328 and an outlet 330. A pump 342 (e.g., pump 42 or 242) is adapted to pump liquid (e.g., water such as sea water) through the flow path 332 from the inlet 328 to the outlet 330. Components 344 as described above can be provide along the flow path 332. A flow-through housing 339 containing a strainer 340 and an electrolytic cell 346 can be provided along the flow path 332 as described above. The system 300 can include a liquid detector 307 or detectors 307 and/or a flow sensor 370 or flow sensors 370 that interface with a controller 302 to provide sensed information that the controller 302 can use to determine whether the pump 342 can operate without risk of overheating damage caused by insufficient liquid in the pump for pumping through the flow path 332. It will be appreciated that one or more of the liquid detectors 307 can be positioned at various sensing locations such as sensing location 380 at the outlet of the pump 342 or sensing location 381 downstream from the pump 342 (e.g., in a flow-through housing incorporated into the flow path 332). If the liquid detector 307 or detectors 307 provide sensed data to the controller indicative of a low liquid condition, the controller 320 can prevent activation of the pump 342 and can generate an error or fault notice to an operator indicating a possible low liquid condition.

The flow sensor 370 or flow sensors 370 can be provided at various locations 382-386 along the flow path 332. Example flow sensor locations can be upstream of the pump 342, downstream of the pump 342, in the pump 342 or at the flow-through housing 339 (e.g., coupled to the outlet of the flow-through housing 339). If the pump 342 is activated under conditions in which insufficient liquid from the flow path 332 is in the pump 342 for the pump 342 for the pump 342 to operate properly, the pump 342 will spin without generating flow through the flow path 332. Thus, an alternative run dry prevention strategy can use flow sensing using one of more flow sensors 370 to identify when insufficient liquid from the flow path 332 is in the pump 342 for the pump 342 to operate properly. Under this type of strategy, rather than preventing the pump 342 from initially starting, the system monitors liquid flow at a location along the flow path 332 after the pump 342 has been activated and shuts down the pump if a reading from a flow sensor 370 senses data indicative of a low liquid condition at the pump 342. The flow sensing occurs shortly after initiation of the pump 342, and if a low liquid condition is detected based on flow data from flow sensor 370, the operation of the pump 342 can be terminated before the pump 342 runs long enough to overheat. In one example, the controller 302 interfaces with the flow sensor 370 and stops power from being supplied to the pump 342 if the flow sensor 370 provides a reading indicative of a condition of insufficient liquid in the pump 342. The flow sensor 370 can be a switch type sensor which simply provides a reading of flow or no flow at a location along the flow path 332. Alternatively, the flow sensor 370 can be configured to sense a flow rate or flow speed at a location along the flow path 332. The controller can identify a low liquid condition of the pump 342 when the data from the flow sensor 370 indicates no-flow after the pump 342 has been activated and flow is expected, or when the flow sensor 370 indicates substantially lower flow than would normally be expected under normal operating conditions. Example flow sensors can include volumetric flow meters such as positive displacement flow meters, velocity flow meters, hall-effect flow meters (e.g., electrode paddle wheel flow meter), mass flow meters, inferential flow meters and ultrasonic flow meters.

It will be appreciated that the controller 302 can interface directly with the flow sensor(s) 370 and/or liquid detector(s) 307; or can interface indirectly with the flow sensor(s) 370 and/or liquid detector(s) 307 (e.g., the controller 302 can interface with an intermediate structure such as another controller that interfaces with the flow sensor sensor(s) and/or liquid detector(s) 307). The controller 302 and/or the intermediate controller may use data from the sensor or sensors (e.g., flow or liquid detection sensors) for additional purposes such as control of operation of the electrolytic cell 346 (e.g., turning the electrolytic cell on and off; varying the power provided to the electrodes of the electrolytic cell). In certain examples, a flow sensor can be integrated into the system of FIG. 2 in combination with or in place of the liquid detector 107 such that the controller 102 can use data from the flow sensor to control shut down of the pump via power relay 182 if the flow sensor provides data indicative of a run-dry condition.

In some examples, both liquid detection and flow sensing techniques can be used in combination to prevent run-dry related pump damage. In other examples, liquid detection alone or only flow sensing alone can be used to prevent run-dry related pump damage.

A preferred application of aspects of the present disclosure relates to water pumps (e.g., water pumps such as pumps adapted or pumping sea water (e.g., marine grade water pumps) with sensing arrangements for detecting when insufficient water is present in the pumps (e.g., for detecting when air is in the pumps) and for preventing the pumps from being starting when such conditions exist. However, it will be appreciated that aspects of the present disclosure are also applicable to liquid pumps in general (e.g., hydraulic fluid pumps, oil pumps, water pumps, etc.) with sensing arrangements for detecting when insufficient liquid is present in the pumps (e.g., for detecting when air is in the pumps) and for preventing the pumps from being starting when such conditions exist. Pump systems in accordance with the principles of the present disclosure can be used on watercraft or for applications other than on watercraft. Systems in accordance with the principles of the present disclosure also relate to the use of flow sensors to detect when pumps have been activated with insufficient water being present to operate properly (e.g., to provide pumping). The flow sensors can interface with controllers that, when an indication of insufficient water is detected by the flow sensors after pump start-up, shut down the pumps before sufficient running time has elapsed to cause damage.

The various examples described above are provided by way of illustration only and should not be construed to limit the scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made with respect to the examples illustrated and described herein without departing from the true spirit and scope of the present disclosure.

Claims

1. A pump system comprising: a pump;a liquid detection sensor mounted to the pump for detecting the presence of liquid within the pump; anda controller that interfaces with the liquid detection sensor and prevents power from being provided to a motor of the pump when the liquid detection sensor indicates insufficient liquid within the pump.

2. The pump system of claim 1, wherein the pump is a magnetic drive pump.

3. The pump system of claim 1, wherein the liquid detection sensor is an electrical conductivity sensor.

4. The pump system of claim 1, wherein the liquid detection sensor is an ultrasonic sensor.

5. The pump system of claim 1, wherein the liquid detection sensor is a magnetic field sensor.

6. The pump system of claim 1, wherein the controller controls a power relay configured for connecting the motor to a power source and for disconnecting the motor from the power source.

7. The water system of claim 6, wherein the controller is powered by the power source.

8. The pump system of claim 7, wherein the controller is electrically isolated from the power relay and the power source.

9. The pump system of claim 8, wherein the power source is an alternating current power source, and wherein an AC/DC converter is provided for converting alternating current from the power source to direct current provided to the controller.

10. The pump system of claim 1, wherein the water pump system is part of an on-board water system of a watercraft.

11. The pump system of claim 1, wherein the pump includes composite plastic/metal parts that are subject to heat damage if the pump is run when insufficient water is present in the pump.

12. The pump system of claim 1, wherein the pump is a water pump.

13. The pump system of claim 1, wherein the pump is a marine grade water pump.

14. The pump system of claim 1, wherein the pump is a water pump adapted for pumping sea water.

15. The pump system of claim 1, wherein the pump includes an impeller and a bearing that allows for rotation of the impeller relative to a housing of the pump, wherein the impeller is configured to rotate within a pump chamber to move liquid from a pump inlet through the pump chamber to a pump outlet under normal operation, and wherein the bearing is positioned to be exposed to and cooled by the liquid during normal operation of the pump.

16. The pump system of claim 15, wherein the bearing is configured to allow the impeller to rotate relative to a shaft, wherein the shaft has a metal or ceramic construction, wherein ends of the shaft are supported by a housing of the pump, wherein the housing has a polymeric construction, and wherein during normal operation of the pump the shaft and portions of the housing supporting the ends of the shaft are exposed to the liquid in the pump.

17. The pump system of claim 16, wherein the impeller is coupled to a plastic body supporting a plurality of magnets, wherein the bearing is mounted between the plastic body and the shaft, and wherein the magnets magnetically couple to a magnetic drive for driving rotation of the impeller.

18. The pump system of claim 1, wherein the controller interfaces directly or indirectly with the liquid detection sensor.

19. A pump system comprising: a pump;a flow sensor for sensing liquid flow in the pump or through a flow path in fluid communication with the pump; anda controller that interfaces with the flow sensor and terminates power to a motor of the pump when the flow sensor generates flow data indicative of the pump running dry.

20. The pump system of claim 19, wherein the pump includes an impeller and a bearing that allows for rotation of the impeller relative to a housing of the pump, wherein the impeller is configured to rotate within a pump chamber to move liquid from a pump inlet through the pump chamber to a pump outlet under normal operation, and wherein the bearing is positioned to be exposed to and cooled by the liquid during normal operation of the pump.

21. The pump system of claim 20, wherein the bearing is configured to allow the impeller to rotate relative to a shaft, wherein the shaft has a metal or ceramic construction, wherein ends of the shaft are supported by a housing of the pump, wherein the housing has a polymeric construction, and wherein during normal operation of the pump the shaft and portions of the housing supporting the ends of the shaft are exposed to the liquid in the pump.

22. The pump system of claim 21, wherein the impeller is coupled to a plastic body supporting a plurality of magnets, wherein the bearing is mounted between the plastic body and the shaft, and wherein the magnets magnetically couple to a magnetic drive for driving rotation of the impeller.

23. The pump system of claim 19, wherein the pump is a magnetic drive pump.

24. The pump system of claim 19, wherein the controller controls a power relay configured for connecting the motor to a power source and for disconnecting the motor from the power source.

25. The water system of claim 24, wherein the controller is powered by the power source.

26. The pump system of claim 25, wherein the controller is electrically isolated from the power relay and the power source.

27. The pump system of claim 26, wherein the power source is an alternating current power source, and wherein an AC/DC converter is provided for converting alternating current from the power source to direct current provided to the controller.

28. The pump system of claim 19, wherein the water pump system is part of an on-board water system of a watercraft.

29. The pump system of claim 19, wherein the pump includes composite plastic/metal parts that are subject to heat damage if the pump is run when insufficient water is present in the pump.

30. The pump system of claim 19, wherein the pump is a water pump.

31. The pump system of claim 19, wherein the pump is a marine grade water pump.

32. The pump system of claim 19, wherein the pump is a water pump adapted for pumping sea water.

33. The pump system of claim 19, wherein the controller interfaces directly or indirectly with the flow sensor.