Patent Application
20140161651
This disclosure relates to various types of pumps that are magnetically driven. More specifically, it pertains to pumps in which a rotary or rotary-reciprocating element, such as a pump gear, is connected to a driven magnet housed in a magnet housing (“magnet cup”) in which the magnet is wetted by the fluid being pumped by the pump.
Integrated-drive pumps are particularly advantageous for pumping systems that must operate under severe conditions, handle hazardous fluids, or operate trouble-free for extremely long periods of time. Such pumps often incorporate a magnetically coupled pump-drive mechanism in which a pump element, such as a pair of interdigitating gears or lobes, is connected to a driven magnet housed in a magnet housing or “magnet cup.” The driven magnet is caused to rotate by a rotating magnetic field induced by a stator or other mechanism situated outside the magnet cup. This arrangement allows the driven magnet to be immersed in the fluid being pumped while isolating the rest of the system and eliminating the leak-prone hydraulic seals that would otherwise be required around the pump-drive shaft. Operation of the stator typically requires an electronic circuit for provision of power and control logic.
In addition to the electronic circuits required for operation of the pump, integrated-drive pumps are often incorporated into hydraulic systems that require sensors or indicators of any of various parameters such as pressure, temperature, conductivity, etc., of the fluid flowing in the system. A sensor usually includes a transducer or the like that converts the parameter being sensed (e.g., pressure or temperature) into a corresponding signal (e.g., an electronic or optical signal). The sensor usually also includes or is connected to an electronic circuit that receives data directly from the transducer and processes the data for use by other electronics for, e.g., providing a measure of the parameter or for use in control circuits. It is possible that the sensor(s) not actually include or function as a transducer. As used herein, the term “sensor” encompasses both transducer-based sensors as well as sensors not utilizing a transducer.
In hydraulic systems including a pump, the pump is typically a discrete stand-alone component, by which is meant that the pump is manufactured and sold separately to original equipment manufacturers (OEMs) for incorporation into the OEM's own system. The trend in many OEM hydraulic systems requiring a pump is toward miniaturization, particularly with respect to the aspect ratio of a pump assembly (i.e., the ratio of a pump assembly's axial length as compared to its diameter) without sacrificing performance or reliability. Thus, the electronic circuitry for operating both the pump and the sensors ideally must be self-contained (i.e., located on or within the housing or enclosure of a pump-driver portion), and incorporated into a pump assembly that is as small and compact as possible.
However, the circuitry needed to operate the stator in an integrated-drive pump is often required to operate at a much higher voltage and/or current than the circuitry for operating the sensors due to the higher electrical power requirements of the stator relative to the sensors. Additionally, each respective circuit type requires numerous circuit elements which can vary in size. The disparity in power requirements, the relatively large number and size of the circuit elements, and the space constraints imposed by the pump-driver portion often necessitate that the stator and sensor elements be operated on two or more independent electrical circuits. Moreover, these independent electrical circuits must often be laid out on multiple printed circuit boards that fully extend the full transverse dimension of the enclosure of the pump-driver portion (or be located outside the enclosure) to accommodate the required circuit elements. This, in turn, blocks access to the magnet cup, complicates sensor location, precludes a flow-through pump configuration, and requires a large pump-driver portion that negatively impacts the size of the pump assembly.
Disclosed embodiments of the present invention provide compact integrated-drive pumps that address the deficiencies of known integrated-drive pumps. Certain embodiments of the present invention concern a pump assembly, comprising a magnetically driven pump-head subassembly and a pump-driver subassembly coupled to the pump-head subassembly. The pump-driver subassembly includes a pump-driver enclosure. The pump-head subassembly comprises a rotatable magnet contained in a magnet cup, which has a distal-end wall and extends into the pump-driver enclosure. The pump-driver subassembly also comprises a printed circuit board contained in the pump-driver enclosure, and a stator mounted to the printed circuit board. The stator coaxially surrounds the magnet cup. The printed circuit board includes a stator-driving circuit, at least one signal-processing circuit, and at least one pump-parameter sensor mounted on the printed circuit board. The printed circuit board also defines a void that is situated relative to the distal-end wall so as to expose at least half of the distal-end wall while placing the sensor relative to the magnet cup. In addition, the pump-driver enclosure has an aspect ratio of no greater than one (unity).
Another embodiment concerns a pump assembly, comprising a pump-head portion including a pump cavity. The pump assembly includes a pump-driver enclosure coupled to the pump-head portion that has an axial length and a transverse dimension. A movable pumping member is situated inside the pump cavity and connected to a driven magnet so that induced motion of the driven magnet causes corresponding induced motion of the pumping member. The pump assembly also includes a magnet cup, being a respective portion of the pump cavity, and containing the driven magnet. The induced motion of the driven magnet occurs in the magnet cup as the driven magnet and interior of the magnet cup are being wetted by fluid being pumped by induced motion of the pumping member. The magnet cup also includes a distal-end wall.
A magnet-driver is situated outside the magnet cup but inside the pump-driver enclosure, and is magnetically coupled to the driven magnet such that a changing magnetic field produced by the magnet-driver induces motion of the driven magnet and hence of the pumping member in the magnet cup. The pump assembly also includes a circuit board and at least one sensor located in the pump-driver enclosure. The sensor is located on, aside, or at least partially in the distal-end wall, and the circuit board is electrically connected to the magnet-driver and to the at least one sensor.
The circuit board comprises a high-current circuit and a low-current circuit, wherein the high-current circuit is connected to and provides controlled electrical power to the magnet-driver, and the low-current circuit is connected to and provides controlled electrical power to the at least one sensor. The circuit board extends orthogonally to the axial length around the magnet cup while defining a void, which allows access through the circuit board to the distal-end wall of the magnet cup.
The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
This disclosure is set forth in the context of representative embodiments that are not intended to be limiting in any way.
As used herein, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the term “includes” means “comprises.” Further, the term “coupled” encompasses mechanical as well as other practical ways of coupling or linking items together, and does not exclude the presence of intermediate elements between the coupled items.
The things and methods described herein should not be construed as being limiting in any way. Instead, this disclosure is directed toward all novel and non-obvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The disclosed things and methods are not limited to any specific aspect or feature or combinations thereof, nor do the disclosed things and methods require that any one or more specific advantages be present or problems be solved.
Although the operations of some of the disclosed methods are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed things and methods can be used in conjunction with other things and method. Additionally, the description sometimes uses terms like “produce” and “provide” to describe the disclosed methods. These terms are high-level abstractions of the actual operations that are performed. The actual operations that correspond to these terms will vary depending on the particular implementation and are readily discernible by one of ordinary skill in the art.
In the following description, certain terms may be used such as “up,” “down,”, “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” and the like. These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. But, these terms are not intended to imply absolute relationships, positions, and/or orientations. For example, with respect to an object, an “upper” surface can become a “lower” surface simply by turning the object over. Nevertheless, it is still the same object.
Referring to
In this embodiment, a printed circuit board (PCB) 36 is located within the pump-driver enclosure 34 immediately above and substantially adjacent the stator 32, as shown in
The PCB 36 contains one or more electronic circuits that, for example, provide controlled electrical power (i.e., electrical power, logical control, signal conditioning, signal processing, etc.) to the stator 32and to the one or more sensors 42. For example, the PCB 36 of this embodiment comprises a high-current electrical circuit for operating the stator 32 and at least one low-current electrical circuit for operating the one or more sensors 42. Desirably, the PCB 36 accommodates all the circuit elements 40 of the circuits required to operate the stator 32 and the one or more sensors 42 such that only a single printed circuit board is required. In this manner, all the electrical components are contained on or within the pump-driver enclosure 34 such that all that is required from outside (i.e., from the OEM system) is electrical power input. The integrated-drive pump assembly 10 can also include an output for signals to or from the sensors 42 for use by, for example, OEM systems remote from the pump assembly.
Alternatively, the necessary electronic circuits can be laid out on two or more PCBs (not necessarily of similar size) substantially adjacent one another (e.g., coaxially “stacked”) or otherwise in close proximity within the pump-driver enclosure 34. Also, the PCB 36 need not be annular, but can comprise any shape that would fit in the pump-driver enclosure 34 and allow access to the distal-end wall 30 of the magnet cup 28 for location of sensors or fittings. For example, the PCB 36 can comprise one or more semi-annular printed circuit boards configured and arranged within the pump-driver enclosure 34 such that the distal-end wall 30 of the magnet cup 28 is accessible.
In the embodiment shown, the PCB 36 is configured such that the distal-end wall 30 of the magnet cup 28 is at least partially exposed through the central hole 46 of the PCB 36 when the PCB 36 is located above the stator 32 (i.e., at least a portion of the distal-end wall 30 of the magnet cup 28 can be accessed through the annular-shaped PCB 36), as best shown in
In an alternative embodiment, the PCB 36 is configured as a flexible printed circuit sheet or “board”, such as a polymeric substrate in/on which circuit wiring is printed and circuit elements are mounted. The flexible printed circuit can be configured as a looped strip or ribbon 50, as shown in
Referring to
Further with respect to sensor location, one or more sensors 42 can be located on or relative to the distal-end wall 30 of the magnet cup 28 and electrically connected to the PCB 36, as shown in
The pump-driver enclosure 34 desirably is cylindrical, with an axial length dimension α and a transverse or radial dimension β, as shown in
For example, the axial length dimension α can be reduced by configuring the pump-driver enclosure 34 such that the hydraulic fitting 44 extends through a distal-end wall 48 of the pump-driver enclosure 34, or by configuring the electrical-connector housing 38 with an angular (e.g., right-angular) bend. Desirably, the aspect ratio can be between approximately 0.4 and 0.7, as shown in
In alternative embodiments the pump-driver enclosure 34 is not cylindrical, but rather has a different shape with sufficient interior volume to accommodate the components necessary to operate the pump assembly. For example, the pump-driver enclosure 34 could be square or rectangular, and could have an aspect ratio defined by the expression α/β, where α is an axial dimension and β is a transverse dimension.
Although the foregoing embodiments include one or more sensors for sensing pump parameters (such as temperature, pressure, etc.) and/or Hall sensors 60 for sensing rotation of the driven magnet 26, alternative embodiments need not include such sensors or include any sensors at all. For example, it is possible to use brushless direct current (BLDC) motor controllers wherein the stator is driven by a circuit that does not require Hall sensors. Similarly, depending upon the requirements of the OEM system into which the integrated-drive pump assembly 10 is incorporated, the pump assembly need not include any parameter-sensing. However, in such alternative embodiments, the distal-end wall 30 of the magnet cup 28 remains exposed, thereby preserving the ability to mount sensors on the distal-end wall 30.
The range of candidate pump-heads is not limited to gear pumps. Exemplary alternative types of pump-head, without intending to be limiting, are valved or valveless piston pumps. A valveless piston pump is disclosed in, for example, U.S. Patent Publication No. 2007-0237658, incorporated herein by reference. See particularly FIG. 11 of this reference and accompanying discussion on pages 9-14 thereof.
Reference is now made to
Another aspect of this disclosure pertains to hydraulic circuits comprising a pump such as any of those described above. An embodiment of a circuit 100 is shown in
It will be understood that this disclosure is directed not only to pump assemblies including pump head, stator, and pump driver, but also to “pump-driver” assemblies comprising the stator mounted to a PCB to which other electronic components are also mounted. Both types of assemblies represent convenient OEM-supplied products.
In view of the many possible embodiments to which the principles of the disclosed invention may be applied, one of ordinary skill in the art will recognize that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of this disclosure. Rather, the spirit and scope of the invention is defined by the following claims.
This application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 61/735,872, filed on Dec. 11, 2012, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61735872 | Dec 2012 | US |
