US20090175715A1

US20090175715A1 - Impeller trap

Info

Publication number: US20090175715A1
Application number: US12/350,300
Authority: US
Inventors: David L. Hardgrove
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-01-09
Filing date: 2009-01-08
Publication date: 2009-07-09

Abstract

A water cooling system of a marine engine includes a water line and a water pump. An impeller trap for the water cooling system includes a cylindrical line section having a wall and a pair of ends. A fitting is disposed on each end of the line section for mating with a corresponding portion of the water line of the water cooling system. The line section is connected to the water line of the water cooling system downstream of the water pump. A screen is disposed in the line section and is secured to an inner surface of the wall of the line section. The screen captures pieces of a water pump impeller in the event that the impeller breaks or shears.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/019,916, filed on Jan. 9, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates generally to the art of water cooling systems for marine engines. More particularly, the invention relates to a trap for capturing pieces that have broken off of an impeller of a water pump in a water cooling system for marine engines. The trap reduces the time, effort and cost associated with servicing the water cooling system in the event that a water pump impeller fails.
2. Background Art
Many marine engines, such as those used on high-performance boats and other boats, are water cooled. That is, in order to keep the engine cool during operation, a water pump draws in cool raw water from outside the boat, and that water is strained and then circulated through a heat exchanger, which is adjacent the boat's engine. The cool raw water absorbs the heat from the engine through the heat exchanger and is then pumped out of the boat. This drawing in of raw water, circulating it, and discharging it is performed by the water cooling system.
The water pump is critical to the water cooling system, as it creates the suction to draw the raw water into the cooling system, to circulate the water through the system, and to then pump it out of the system. In order to generate the force to operate, the water pump includes an impeller, which has blades that typically are made of rubber or a soft polymer. As is known to those skilled in the art, the impeller typically is round and seats in an eccentric opening that is formed in the housing of the water pump. This configuration causes the impeller blades to bend within the housing of the water pump, which creates the force for the water pump to operate, but also places the impeller blades under stress. Over time, this stress can cause the impeller blades to break. Thus, if the impeller is not regularly replaced, the blades may break while the water pump is in service. In addition, the impeller depends on water flow to lubricate the blades within the housing of the water pump. As a result, if the engine is started while the boat is not in the water, raw water is not drawn into the cooling system, and there is no water flow to lubricate the impeller blades. This lack of lubrication often causes the impeller blades to shear or break.
When the impeller blades shear or break, there are pieces of the rubber blades that pass from the water pump into components of the cooling system that are downstream of the pump. Such pieces may then plug components of the water cooling system and thus impair the functioning of the system. For example, the heat exchanger typically is downstream of the water pump. The pieces from the sheared or broken impeller blades may pass to the heat exchanger, which contains many small tubes. The pieces may then plug the tubes of the heat exchanger, which reduces or prevents the circulation of water through the heat exchanger, which may cause the engine to overheat and may thus damage the engine. As a result, when an impeller blade shears, the pieces of the blade must be removed from the cooling system in order to prevent damage to the cooling system, engine, and/or other components.
In prior art water cooling systems, the impeller blade pieces travel through the cooling system, requiring substantial disassembly of the cooling system so that all of the pieces of the impeller blades may be located and removed. For example, the heat exchanger may have to be removed and partially disassembled in order to locate all of the impeller blade pieces. Such disassembly of the prior art systems requires a great deal of effort, and therefore is time consuming and costly.
Therefore, a need exists in the art for an apparatus to prevent broken or sheared water pump impeller blades from traveling through the water cooling system. The present invention satisfies this need by providing an impeller trap that captures such broken impeller blade pieces and thus reduces the effort, time, and cost associated with servicing a water cooling system when a water pump impeller fails.

BRIEF SUMMARY OF THE INVENTION

An objective of the present invention is to provide an impeller trap that captures broken impeller blade pieces.
Another objective of the present invention is to provide an impeller trap that reduces the time, effort and cost of servicing a water cooling system when an impeller fails.
Yet another objective of the present invention is to provide an impeller trap that enables a user to determine when an impeller has likely failed and thus needs to be cleaned out of a water cooling system.
These objectives and others are obtained by the impeller trap of the present invention. In an exemplary embodiment of the invention, the impeller trap is for a water cooling system for a marine engine, and the impeller trap includes a cylindrical line section having a wall and a pair of ends. A fitting is disposed on each end of the line section for mating with a corresponding portion of a water line of the water cooling system. A screen is disposed in the line section and is secured to an inner surface of the wall of the line section. The screen captures pieces of a water pump impeller in the event that the impeller breaks or shears.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiment of the invention, illustrative of the best mode in which applicant has contemplated applying the principles of the invention, is set forth in the following description and is shown in the drawings, and is particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is a schematic diagram of a water cooling system for a marine engine of the prior art;

FIG. 2 is an enlarged end view of a water pump impeller seated in a water pump housing of the prior art;

FIG. 3 is a side elevational view of the impeller trap of the present invention, with selected hidden components represented by dashed lines; and

FIG. 4 is an enlarged cross-sectional view of the impeller trap of the present invention taken along line 4-4 in FIG. 3.

Similar numerals refer to similar parts throughout the drawings.

DETAILED DESCRIPTION OF THE INVENTION

So that the structure, operation and advantages of the impeller trap of the present invention can best be understood, a typical prior art water cooling system for a marine engine is shown in FIGS. 1 and 2, and now will be described. With particular reference to FIG. 1, a water cooling system for a marine engine is indicated generally at 10. Raw water is drawn into cooling system 10 through an inlet 12, as shown by arrow W, which indicates the flow of water into the system. The raw water enters a water conduit or water line first section 14A, which leads to a sea strainer 16. Sea strainer 16 is a device through which the raw water is drawn and is designed to filter out debris, sand, refuse and the like, before the raw water is circulated through the remainder of cooling system 10. Sea strainer 16 typically is positioned to be easily accessible for cleaning and/or replacement.
The raw water is communicated from sea strainer 16 through a water line second section 14B, which leads to a water pump 18. Water pump 18 provides the pumping action that draws the raw water into cooling system 10, circulates the raw water within the cooling system, and then discharges the raw water from the system. With additional reference now to FIG. 2, in order to provide such pumping action, water pump 18 includes a housing 24 in which an eccentric opening 26 is formed. An impeller 28, which typically is made of an elastomer/rubber or a soft polymer, seats in eccentric opening 26. Impeller 28 includes blades 30, which bend where they come into contact with certain portions of the wall of housing 24, due to the shape of eccentric opening 26. This configuration of impeller 28 seated in water pump housing 24 with eccentric opening 26 enables water pump 18 to generate sufficient force to circulate the water through cooling system 10 when the impeller is rotatably driven by a motor (not shown).
Impeller blades 30 rotate during operation of water pump 18 as impeller 28 is driven, and as they come into contact with portions of the wall of housing 24 due to eccentric opening 26, they bend and are placed under stress. As a result, over time, blades 30 may break or shear. In the prior art, once blades 30 break, the broken pieces pass into the remainder of water cooling system 10. Returning now to FIG. 1, after water pump 18, a water line third section 14C leads to a heat exchanger 20, which is adjacent the engine (not shown). As is known to those skilled in the art, heat exchanger 20 includes a number of small tubes, which enable the raw water to pass through the heat exchanger and absorb heat from the engine, thereby keeping the engine cool. In some water cooling systems 10, the raw water may also pass through an oil cooler (not shown). Then, the raw water passes through a fourth water line section 14D and through an outlet 22, whereupon the raw water exits water cooling system 10, as shown by arrow X.
When impeller blades 30 break, pieces of the impeller blades may pass through water line third section 14C to heat exchanger 20. These pieces of impeller blades 30 may block water line third section 1 4C and/or tubes of heat exchanger 20, thereby reducing or preventing raw water from circulating through water cooling system 10, which in turn may undesirably cause the engine to overheat. Thus, when impeller 28 fails, water cooling system 10 must be disassembled to locate and remove pieces of impeller blades 30 from third water line section 14C and/or heat exchanger 20. Such disassembly requires a great deal of effort and thus is undesirably time consuming and costly. The impeller trap of the present invention overcomes the disadvantages of the prior art by capturing pieces of impeller blades 30 in an isolated and discrete component, which is easily removed, cleaned and reinstalled, as now will be described.
It is to be understood that the drawings of the present invention are for showing an exemplary embodiment of the invention, and not for limiting the same. An exemplary embodiment of an impeller trap of the present invention is indicated generally at 40 and is shown in FIGS. 3 and 4. Impeller trap 40 of the present invention includes a cylindrical conduit or line section 42, which enables the trap to be easily installed in a convenient area of water line third section 14C, for example, in an area such as box A shown in FIG. 1. Line section 42 of impeller trap 40 includes a wall 52, which preferably is formed of a corrosion-resistant metal, for example, stainless steel, and is of the same or a similar diameter as water line third section 14C. In order to enable impeller trap 40 to be easily removed from water line third section 14C and then reinstalled, the impeller trap includes fittings 44 disposed on each one of a pair of ends 58 of line section 42. Fittings 44 may be threaded connections that mate with corresponding threaded connections installed on water line third section 14C, quick disconnect couplers, or rubber hose sections which enable line section 42 to be attached to water line third section 14C with hose clamps.
Seated inside line section or replaceable conduit 42 is a screen 46. Screen 46 preferably is a heavy-duty screen that is secured to an inner surface 54 of wall 52 of line section 42 by one or more welds 50. Alternatively, screen 46 may be secured to inner surface 54 of wall 52 of line section or replaceable conduit 42 by means of shoulders, rings, mechanical fasteners, an adhesive, an interference fit, or other means known in the art.
Screen 46 catches pieces of broken impeller blades 30 that are being conveyed from water pump 18 through third water line section 14C. As mentioned above, screen 46 preferably is a heavy-duty screen, so that pieces of impeller blades 30 will not cause the screen to fail. The mesh size or opening size of screen 46 may be adjusted depending on the particular cooling system 10, and such mesh size is sufficient to ensure good water flow, while being small enough to catch pieces of impeller blades 30 that may plug any components of the system. Preferably, the mesh size or opening size of screen 46 is set to ensure that each opening in the screen is about one-half the size of the smallest restriction in cooling system 10 after or downstream of water pump 18. For example, the mesh openings may be one-half the size of the smallest restriction in an oil cooler, which typically has the smallest restriction in cooling system 10 after water pump 18. Such a size will enable screen 46 to capture pieces of impeller blades 30 that may plug any components of cooling system 10, while allowing extremely small pieces to pass through the system and be discharged.
Impeller trap 40 preferably is relatively short, for example, about six (6) to eight (8) inches long, which enables the trap to be easily removed from third line section 14C and then re-installed. Line section 42 may be straight, or it may alternatively be angled, for example, at a 45° angle, a 90° angle, or any other suitable angle to easily fit the configuration of third line section 14C.
When an impeller 28 fails, impeller trap 40 captures the pieces of blades 30 and is able to be easily removed, cleaned and re-installed. More particularly, when impeller blades 30 shear, they are captured and trapped by screen 46 in impeller trap 40. By releasing and/or loosening fittings 44, impeller trap 40 is easily removed from third line section 14C. Because the water is pumped into impeller trap 40 in one direction by water pump 18, indicated by arrow Y in FIG. 3, the pieces of broken impeller blades 30 will be trapped against the “upstream” side, or Y-side, of screen 46. Upon removal of impeller trap 40 from water line third section 14C, a user can simply rinse out the impeller trap from the opposite or “downstream” side of screen 46, and then easily can re-install the impeller trap in water line third section 14C by coupling and/or tightening fittings 44.
An additional feature of impeller trap 40 is a pressure port 48. That is, a pressure port or gauge bung 48 preferably is formed in wall 52 of line section 42 upstream of screen 46. Pressure port 48 includes an inner surface 56, which preferably is formed with suitable means for inserting a pressure gauge (not shown) into line section 42 and securing the pressure gauge to the line section, for example, one-eighth inch female pipe threads. Alternatively, means such as pipe threads may be formed on an outer surface of pressure port 48 to enable the pressure gauge to be inserted and secured to line section 42.
In this manner, a pressure gauge may be inserted into pressure port 48 and thus line section 42 in order to determine the pressure in impeller trap 40. If the pressure reading is at a standard level, water pump 18 is functioning properly and impeller 28 likely is intact. If the pressure reading is high, foreign debris is likely trapped by screen 46, thereby blocking line section 42 and causing the pressure in impeller trap 40 to increase. In this manner, an increased pressure reading enables a user to easily determine when it is necessary to remove impeller trap 40 for cleaning. If there is no pressure reading, water pump 18 may be malfunctioning, including a failure of impeller blades 30, thereby enabling the user to determine that water pump 18 and/or impeller trap 40 should be checked, and the impeller trap cleaned. The pressure gauge or transducer that is inserted into pressure port 48 may be a simple gauge which provides a convenient readout or display adjacent impeller trap 40, or may be wired to a readout on the dashboard of the boat.
In this manner, impeller trap 40 of the present invention captures pieces of broken impeller blades 30 before they are able to travel into the remainder of cooling system 10 and plug components of the system. Impeller trap 40 is a discrete unit that is easily removable, which enables a user to remove it, clean it, and re-install it into cooling system 10 with minimal effort, time and cost. As a result, the effort, time and cost associated with servicing water cooling system 10 when water pump impeller 28 fails is minimized through the use of impeller trap 40 of the present invention. Moreover, impeller trap 40 provides a pressure port 48 which enables a user to insert a pressure gauge and determine when impeller 28 has likely failed and thus needs to be cleaned. Screen 46 of impeller trap 40 may also catch debris that makes it past sea strainer 16, thereby capturing additional debris that could impair the operation of water cooling system 10.
It is to be understood that impeller trap 40 of the present invention may be used in any type of water cooling system 10 for marine engines, including systems other than those shown and described above, without affecting the overall concept or operation of the invention. In addition, the design and/or construction of components of impeller trap 40 may be adjusted for particular design requirements without affecting the concept or operation of the invention. For example, while line section 42 of impeller trap 40 has been described above as preferably being formed of a corrosion-resistant metal, for example, stainless steel, it may alternatively be formed of other corrosion-resistant metals, including aluminum alloys, or of other corrosion-resistant materials, for example, rubber or plastic. In the event that line section 42 of impeller trap 40 is formed of rubber, the connection of the impeller trap to third line section 14C may be facilitated by hose clamps, and screen 46 is retained in the impeller trap by mechanical means, for example, shoulders, rings or fasteners, or by an adhesive.
Accordingly, the impeller trap of the present invention is simplified, provides an effective, safe, inexpensive, and efficient structure which achieves all the enumerated objectives, provides for eliminating difficulties encountered in the prior art, and solves problems and obtains new results in the art.
In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described. Potential modifications and alterations will occur to others upon a reading and understanding of this disclosure, and it is understood that the invention includes all such modifications and alterations and equivalents thereof.
Having now described the features, discoveries and principles of the invention, the manner in which the impeller trap is constructed, arranged and used, the characteristics of the construction and arrangement, and the advantageous, new and useful results obtained; the new and useful steps, structures, devices, elements, arrangements, parts and combinations, are set forth in the appended claims.

Claims

1. An impeller trap for a water cooling system for a marine engine, comprising:

a cylindrical line section having a wall and a pair of ends;

a fitting disposed on each one of said ends of said line section, for mating with a corresponding portion of a water line of said water cooling system; and

a screen disposed in said line section and secured to an inner surface of said wall of the line section, whereby said screen captures pieces of a water pump impeller in the event of breakage of said impeller.

2. The impeller trap of claim 1, wherein said impeller trap is a discrete unit that is selectively removable from said water line of said water cooling system.

3. The impeller trap of claim 1, wherein said line section is connected to said water line of said water cooling system downstream of a water pump of said water cooling system and upstream of a heat exchanger of the water cooling system.

4. The impeller trap of claim 1, wherein said screen is secured to said inner surface of said line section wall by means selected from the group consisting of a weld, shoulders, rings, mechanical fasteners, an adhesive, and an interference fit.

5. The impeller trap of claim 1, wherein said screen is a heavy-duty screen.

6. The impeller trap of claim 1, wherein said screen includes mesh openings that are one-half the size of the smallest opening in said water cooling system downstream of a water pump.

7. The impeller trap of claim 1, wherein said line section is formed of a corrosion-resistant material.

8. The impeller trap of claim 7, wherein said corrosion-resistant material is selected from the group consisting of stainless steel, an aluminum alloy, rubber, and plastic.

9. The impeller trap of claim 1, wherein said line section is from about six inches to about 8 inches long.

10. The impeller trap of claim 1, wherein said line section is straight.

11. The impeller trap of claim 1, wherein said line section is angled.

12. The impeller trap of claim 1, wherein said fittings are selected from the group consisting of threaded connectors, quick disconnect couplers, and hose clamps.

13. The impeller trap of claim 1, further comprising a pressure port formed in said wall of said line section upstream of said screen for receiving a pressure gauge.

14. The impeller trap of claim 13, wherein said pressure port is formed with threads to accept mating threads that are formed on said pressure gauge.