Patent Application
20120177511
1. Field of the Invention
The present invention generally relates to pump rotor and rotatable driving element assemblies, and more particularly to pump rotor assemblies that include a rotor and rotatable driving element that are connected together. The assemblies have two main versions, based on the type of driving element and seal between the housing and the driving element, with the first being dynamically-sealed and the second being statically-sealed, such as with a magnetically coupled or canned-motor version.
2. Discussion of the Prior Art
There are a variety of pump assembly designs that include a rotor, otherwise known as a drive pump element, such as for example an impeller, drive gear, drive screw or lobe. It is common for such a rotor or drive pump element to be integrally formed with a rotatable driving element, such as for example a drive shaft, inner magnet or armature of a centrifugal or rotary pump. Such structures may be used in a variety of pumps, such as for example pumps that are in the form of an internal gear, external gear, vane, lobe, circumferential piston, screw pump, or other pump structures.
The existing pump designs can be classified as being in one of two categories, namely dynamically-sealed or statically-sealed, with the statically-sealed having a driving element that is magnetically driven and being of the magnetically coupled or canned-motor type. In the first category of dynamically-sealed pumps, the pump includes a dynamic shaft seal. These pumps typically have a rotor integrally formed with a rotatable driving element in the form of a drive shaft.
In the second category, which includes statically-sealed pumps in the form of magnetically-coupled or canned-motor pumps, the pump includes a rotatable driving element that includes an inner magnet assembly or an armature assembly. In some instances, it is desirable to avoid potential seal leakage by not using seals in conjunction with rotating parts. Accordingly, it has become fairly common in the pump arts to employ a magnetic drive system to eliminate the need for seals along rotating surfaces. While such pumps may still employ static seals, because of their lack of dynamic or rotational seals, they have become known as “sealless” pumps.
The existing designs have inherent disadvantages because the pump rotor, which is a primary wear component, is expensive and difficult to repair, replace or upgrade. With existing designs, the rotor is not accessible while the pump is installed and connected to a piping system, foundational base plate, motor driver, an intermediate driving structure and to other necessary support systems, such as heating, cooling, quench, or flush fluid systems and/or insulation. The existing designs require users to remove the pump from service and bring it to a service facility for cleaning, disassembly and repair. Because this process is time consuming, some users keep spare pumps on hand in an effort to maintain production uptime. This increases inventory costs and requires a complete interim pump installation, with the accompanying connections of all structural and system elements.
The prior art rotor support bearings, which could be in the form of ball or roller bearings or bushings, which will be collectively referred to herein as rotor support bearings, are another primary wear component. The rotor support bearings also are expensive to repair, replace or upgrade. As with the rotor, the rotor support bearings are not accessible while the pump is in place and connected to the foundational base plate and other system components. Thus, the pump must be removed from service, incurring the same setbacks as when servicing a rotor.
Another disadvantage of existing designs is that the rotor and rotor support bearings are unique to a given pump type and installation. Thus, if it is desired to change the pumping principle or performance of such a prior art pump, one must remove the entire integral rotatable drive element and rotor to exchange it for a different integral rotatable drive element and rotor. The disassembly also typically involves a complex repair that can include interference press fits, heat shrink fits, special tools or fixtures and welded assemblies. In addition, when repairing, replacing or upgrading the rotor or rotor support bearings on a magnetically-coupled pump, the driving portion that is configured as an inner magnet assembly of a magnetically coupled pump must be separated from the outer magnet assembly. This raises a significant safety issue because separating the magnets of the driving portion from the outer magnet assembly requires overcoming large magnetic forces, which requires very significant decoupling forces applied to separate the magnetic coupling and then difficulty in controlling the driving portion once it is decoupled.
The present disclosure addresses shortcomings found in prior art integral rotor and drive portion assemblies.
The present disclosure generally provides modular pump rotor assemblies having improvements in construction wherein a rotor and a rotatable driving element are removably connected together with removable fasteners. The improvements further include a rotor support bearing that is disposed between the rotor and the rotatable driving element, and that may be held in place by a clamping force between the rotor and the rotatable driving element.
In a first aspect, a modular pump rotor assembly includes a rotatable driving element and a rotor, with the rotor being removably connected to the rotatable driving element by at least one removable fastener.
In another aspect, the modular pump rotor assembly may include a rotor support bearing that is disposed between the rotatable driving element and the rotor.
In a further aspect, the rotatable driving element of the modular pump rotor assembly may include a rotatable shaft.
In another aspect, the modular pump rotor assembly may include a clamp plate disposed between and connected to the rotatable shaft and the rotor.
In yet another aspect, the modular pump rotor assembly may include a rotor support bearing disposed between the rotatable shaft and the clamp plate.
In a further aspect, the rotatable driving element of the modular pump rotor assembly may be constructed to include an inner magnet assembly.
In a further aspect, the modular pump rotor assembly may include a rotor support bearing disposed between the inner magnet assembly and the rotor.
In another aspect, the modular pump rotor assembly may be configured to be separately removably connected to at least two rotors having different configurations.
In a further aspect, the modular pump rotor assembly may include at least one removable fastener that removably connects the rotor to the rotatable driving element and the at least one removable fastener may include a plurality of fasteners that are located in a symmetrical configuration with respect to a rotational axis of the rotor.
In another aspect, a modular pump rotor assembly for use in a pump having a housing and a seal that engages the housing, may include a rotatable driving element and a rotor, with the rotor being removably connected to the rotatable driving element by at least one removable fastener.
In another aspect, the modular pump rotor assembly may further include a rotor support bearing disposed between the rotatable driving element and the rotor.
In a further aspect, the modular pump rotor assembly may be for use in a pump housing having a dynamic shaft seal and the rotatable driving element may include a rotatable shaft that engages the dynamic shaft seal.
In another aspect, the modular pump rotor assembly for use in a pump may include a clamp plate removably connected to a rotatable shaft by at least one removable fastener, and the rotor may be removably connected to the clamp plate by at least one removable fastener.
In a further aspect, the modular pump rotor assembly for use in a pump may further include a rotor support bearing that is disposed between the rotatable shaft and the clamp plate.
In a further aspect, the modular pump rotor assembly for use in a pump may be configured to have the rotor support bearing clamped between the rotatable shaft and the clamp plate when at least one removable fastener that connects the clamp plate to the rotatable shaft is installed.
In another aspect, the modular pump rotor assembly for use in a pump may be configured to include that the at least one removable fastener that removably connects the rotor to the clamp plate also includes a plurality of removable fasteners that are located in a symmetrical configuration with respect to a rotational axis of the rotor.
In a further aspect, the modular pump rotor assembly for use in a pump may include a rotatable driving element that is configured to be separately removable connected to at least two rotors that have different configurations.
In a further aspect, the modular pump rotor assembly is for use in a pump housing that may have a static seal between the pump housing and the rotatable driving element and the rotatable driving element may include a rotatable magnetic driving element that does not engage the static seal.
In another aspect, the modular rotor assembly is for use in a pump housing that may have the rotor removably connected to the rotatable driving element by at least one removable fastener, and the modular pump rotor assembly may include a rotor support bearing that may be disposed between a rotatable magnetic driving element and the rotor.
In a further aspect, the rotatable driving element of the modular rotor assembly for use in a pump housing may include an inner magnet assembly that includes magnets.
In a further aspect, the rotatable driving element of the modular rotor assembly for use in a pump housing may include an inner magnet assembly that includes a sleeve that covers magnets.
In another aspect, the rotatable inner magnet assembly of the modular driving element of the modular rotor assembly for use in a pump housing may include a magnet mounting portion and a sleeve that covers magnets and is sealed to the magnet mounting portion.
In further aspect, the sleeve that may cover a rotatable inner magnet assembly of the modular driving element of the modular rotor assembly for use in a pump housing may include indentations that correspond to and bias magnets inward against a magnet mounting portion.
Thus, the present disclosure presents alternatives to integrally formed rotor and rotatable drive portions that previously were not modular in design and that exhibited the aforementioned disadvantages. The present disclosure provides structures that permit removal of a rotor and/or rotor support bearing from a rotatable drive element without requiring the time and labor-intensive full removal of a pump from a piping system, and in some instances the potentially dangerous conditions such as the need to decouple a magnetic drive element from an outer driven element in a magnetically coupled arrangement.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and provided for purposes of explanation only, and are not restrictive of the subject matter claimed. Further features and objects of the present disclosure will become more fully apparent in the following description of example embodiments and from the appended claims.
In describing the preferred examples, reference is made to the accompanying drawing figures wherein like parts have like reference numerals, and wherein:
It should be understood that the drawings are not to scale. While some mechanical details of dynamically sealed and magnetically driven pumps or canned-motor pumps, including details of fastening means and other plan and section views of the particular components, have been omitted, such details are considered within the comprehension of those skilled in the art in light of the present disclosure. It also should be understood that the present disclosure is not limited to the examples illustrated.
Referring generally to
This example further includes a clamp plate 18 that is disposed between the rotatable driving element 12 and the rotor 14. While it will be understood that one or more other connecting elements or fasteners may be used, the clamp plate 18 is shown as being connected to the rotor 14 by removable fasteners 20. The removable fasteners 20 are shown as threaded bolts that are configured to pass through respective bores 22 in the rotor 14 and to engage threaded bores 24 in the clamp plate 18. It will be appreciated that if a plurality of removable fasteners will be used, then using a configuration wherein a corresponding plurality of the threaded bores 24 are located in a symmetrical configuration with respect to a rotational axis R of the rotor 14 will, in turn, allow the removable fasteners 20 to be located in a symmetrical configuration with respect to the rotational axis R of the rotor 14, so as not to cause any rotational imbalance. As shown with respect to the clamp plate 18, there may be additional bores provided to accommodate more connection variations with respect to a given clamp plate. This will be discussed later herein in regard to
As seen in the example shown in
As best seen in
The pump housing 52 also includes a first housing portion 62 that has a first end 64 and a second end 66. The first housing portion 62 is connected at its first end 64 to the first head 59 by conventional means. A centrally located second housing portion 68 has a first end 70 and a second end 72. The second housing portion 68 is connected at its first end 70 to the second end 66 of the first housing portion 62. A third housing portion 74 has a first end 76 and a second end 78. The third housing portion 74 is connected at its first end 76 to the second end 72 of the second housing portion 68 by conventional means. The second end 78 of the third housing portion 74 is connected to a second head 80 by conventional means. The second head 80 includes a bore 82 for a fixed shaft 84 for rotatable support of an inner gear 86. The conventional means by which the various housing components are connected together are not shown and may include, for instance, threaded fasteners, press fits, welding or other suitable means as would be consistent with the need to connect and seal some of the respective connections, and to be able to disassemble the pump housing 52 at particular connections.
The structure of the pump 50 and modular rotor assembly 10 permit a user to open the pump housing 52 by removing the second head 80 from the second end 78 of the third housing portion 74. This permits one to gain access to the modular rotor assembly 10 while the pump 50 continues to have the housing 52 mounted to a foundational base plate (not shown) and connected to a piping system (not shown), for example, at a port 88. This then allows one to remove the removable fasteners 20 from the threaded bores 24 in the clamp plate 18 to permit withdrawal of the rotor 14 from the pump 50. The rotor 14 then may be serviced or individually replaced, without having removed the pump 50 from service, without affecting the dynamic seal 52, and virtually without any further disruption to the remaining components of the pump 50.
One will appreciate that the rotor 14 may otherwise be withdrawn with the clamp plate 18 and removed from the pump 50 by removing the removable fastener 32 from the stepped bores 36, 38 in the clamp plate 18 and from the threaded bore 40 in the end 42 of the rotatable shaft 12. This then also would allow one to remove the rotor support bearing 16 from the stem 28 of the rotatable shaft 12 to be repaired or replaced. To affect such a removal of the rotor support bearing 16, the rotor support bearing 16 may be constructed with threaded bores at its outer end or other means for attaching a pulling instrument (not shown) to the rotor support bearing 16 to grasp and pull the rotor support bearing 16 from the rotatable shaft 12. While servicing the rotor support bearing 16, the rotor 14 also may be separated from the clamp plate 18 and replaced or otherwise serviced, as needed. Reassembly of the removed components merely would require reversal of the particular disassembly steps and tightening or engagement of any respective removable fasteners 20 or 32, such as are shown in this example as threaded bolts.
One of skill in the art also will appreciate that the pump 50 may be modified by reassembling the pump with a different rotor outer gear and a different inner gear and second head and fixed shaft, as desired. One also may modify the pump upon reassembly to utilize a different pumping principle by replacing the rotor 14 that is in a configuration of an outer gear of an internal gear pump with a different rotor having a different configuration, such as may be used with a sliding vane design, or other pump. This may be done while installing a corresponding, new second head in place of the second head 80 that was used with a fixed shaft 84 and an inner gear 86, or as otherwise desired. Thus, beyond the improvements in serviceability and uptime that would be provided for a pump, one may alternatively utilize the disclosed structures to implement a pump that is easily modifiable to accommodate changes in the pumping means or pumping principle by including a rotatable driving element that is configured to be separately removably connected to at least two rotors having different configurations. This will be better appreciated when viewing
Turning to
The rotatable driving element 112 of this example includes a magnet mounting portion 118 preferably having an end 119, and an outer surface 120 having a plurality of magnet landings 122 for receiving and locating a plurality of magnets 124. When constructed for use in pumping corrosive materials, it is preferable to make the rotatable driving element 112 and rotor 114 of stainless steel, but it is advantageous to include an annular carbon steel portion between the magnet mounting portion 118 and the magnets 124.
The rotor 114 is shown as being removably connected to the rotatable inner magnet assembly 112 by removable fasteners 126. While it will be understood that one or more other connecting elements or fasteners may be used, the removable fasteners 126 are shown as threaded bolts that are configured to pass through respective bores 128 in the rotor 114 and to engage threaded bores 130 in the end 119 of the rotatable driving element 112. The removable fasteners 126 are located in a symmetrical configuration with respect to a rotational axis R′ of the rotor 114. Similarly to the example shown in
Returning to the example shown in
As best seen in
Alternatively, the bearings 160 and shaft 162 may be eliminated in favor of mounting the cup-shaped drive member 166 directly on the shaft of an external power source. Similarly, the drive member 166 and rotatable shaft 162 may be integrally formed as one piece. The drive member 166 may be constructed of a rigid material, such as that which is used in the housing, for instance, steel, stainless steel, cast iron or other metallic materials, or structural plastics or the like. The outer magnet assembly 164 has magnets 174 within the recess 170 where they are connected to the inner walls of the cup-shaped drive member 166. The magnets 174 may be of any configuration, but are preferably rectangular and may be connected to the drive member 166 by any suitable means, such as by chemical means, including by epoxy, adhesives or the like, or mechanically by fasteners, such as by rivets or the like, or by an outer retaining member, such as will be described with respect to the structures shown in
Disposed at least partially within the recess 170 of the outer magnet assembly 164 is the canister 155, which generally is in the shape of a bell or a cup having an outer rim 156. The canister 155 may be constructed of any of a variety of rigid materials, and the material is typically chosen based on the medium to be pumped, but is preferably constructed of stainless steel, such as alloy C-276, but also may be constructed of other metals, alloys, plastic, composite materials or the like. The canister 155 is open at one end forming a recess 176 surrounded by the outer rim 156. A second housing portion 180 is connected at a first end 182 to the second end 179 of the first housing portion 158, by conventional means, such as discussed above with respect to the example embodiment in
In this example of a magnetically coupled pump 150, when fully assembled, the magnet mounting portion 118, and magnets 124 are disposed within the recess 176 of the canister 155, so as to be separated from the magnets 174 of the outer magnet assembly 164 by the annular canister 155. The rotatable driving element 112 and its magnet mounting portion 118 are arranged to place the respective magnets 174, 124 in substantial magnetic alignment to form a magnetic coupling. This magnetic coupling allows the magnet mounting portion 118 and the rotatable driving element 112 to have no physical contact with but be rotated and thereby driven by rotation of the outer magnet assembly 164.
A second end 184 of the second housing portion 180 of the pump housing 152 is connected (and understood to be sealed) to a head assembly 186, by conventional means, such as by fasteners 188. In this example pump 150, an offset stationary shaft 190 has a first shaft portion 192 having a first longitudinal axis and a second shaft portion 196 having a second longitudinal axis that is parallel to but spaced from the longitudinal axis of the first shaft portion 192. The first shaft portion 192 is held within a bore 194 in the head assembly 186. The first shaft portion 192 of the offset stationary shaft 190 rotatably supports an inner gear 195 that acts with an outer gear, in the form of the rotor 114, to pump a medium. In this example, the second shaft portion 196 of the offset stationary shaft 190 is held within a bore 198 in a shaft support 200 that is configured as a canister insert that is supported by the canister 155. However, it will be appreciated that other shaft and supporting arrangements are possible.
The rotatable driving element 112 includes a bore 202 that receives the rotor support bearing 116 for rotatable coupling to the stationary shaft 190. The rotor 114 is connected to the rotatable driving element 112, as discussed above. With this structure of the example pump 150 and the modular pump rotor assembly 110, it will be appreciated that a user may open the pump housing 152 by removing the head 186 from the second end 184 of the second housing portion 180, thereby gaining access to the inner gear 195, the offset shaft 190 and the modular rotor assembly 110. This access is available while the pump 150 continues to have the housing 152 mounted to a foundational base plate (not shown) and connected to a piping system (not shown), for example, at a port 204. The inner gear 195 and/or offset stationary shaft 190 may be serviced or replaced. This further allows one to remove the removable fasteners 126 from the threaded bores 130 in the rotatable driving element 112 to permit withdrawal of the rotor 114 from the pump 150. The rotor 114 then may be serviced or individually replaced, without having removed the pump 150 from service, without affecting the static seal 154 of the canister 155, and virtually without any further disruption of the remaining components of the pump 150.
One will appreciate that after removing the head 186, the inner gear 195, offset stationary shaft 190, and rotor 114, the rotor support bearing 116 is accessible for removal from the rotatable driving element 112 to be repaired or replaced. To affect such a removal of the rotor support bearing 116, the rotor support bearing 116 may be constructed with threaded bores at its outer end or other means for attaching a pulling instrument (not shown) to the rotor support bearing 116 to grasp and pull the rotor support bearing 116 from the rotatable driving element 112. Reassembly of the removed components merely would require reversal of the particular disassembly steps and tightening or engagement of any respective removable fasteners 126, such as are shown in this example in the form of threaded bolts.
One of skill in the art also will appreciate that the pump 150 may be modified by reassembling the pump with a different rotor outer gear and a different inner gear and second head and corresponding fixed shaft, respectively, as desired. One also may modify the pump upon reassembly to utilize a different pumping principle by replacing the rotor that is in a configuration of an outer gear of an internal gear pump with a different rotor having a different configuration, such as may be used with a sliding vane design, or other pump. This may be done while installing a corresponding stationary shaft and/or a new head in place of the head 186, as needed to cooperate with a different stationary shaft and/or inner gear, or as otherwise desired. Thus, beyond the improvements in serviceability and uptime that would be provided for a pump, one may alternatively utilize the disclosed structures to implement a pump that is easily modifiable to accommodate changes in the pumping means or pumping principle by including a rotatable driving element that is configured to be separately removably connected to at least two rotors having different configurations. As noted above, this will be better appreciated when viewing
The rotor 114 may be of various constructions, such as in the form of an outer gear of an internal gear pump. The gear portion of rotor 114 also may be constructed of various rigid materials, depending on the medium to be pumped. For instance, it may be preferable to make the rotor 114, as well as the magnet mounting portion 118 of steel when such a pump is intended for use in pumping non-corrosive materials.
As noted above, the magnet mounting portion 118 preferably has magnets 124, connected to its outer surface 120 at magnet landings 122. When a pump 150 is made for use in pumping corrosive materials, it is preferable to make the magnet mounting portion 118 of stainless steel, but it is advantageous to include an annular carbon steel portion (not shown) between the magnet mounting portion 118 and the magnets 124. As best seen in the alternative modular pump rotor assembly 110′ shown in
In the alternative example of a rotatable driving element 112′ shown in
Turning to
To enhance the interchangeability of the respective components, each of the rotatable driving elements 12, 112″ and 412 is shown with a respective symmetrical pattern of six threaded bores 24, 130″ and 430, which may be utilized interchangeably with the pattern having three bores 22 in the rotor 114 or with the pattern that will be understood to include six similarly symmetrically spaced bores 322 of the alternative rotor 314 for pumps having a sliding vane design. These are but a few of what will be understood to be many different rotor and rotatable driving element combinations that may be provided for based on the teachings of the present disclosure.
It will be appreciated that a modular rotor assembly in accordance with the present disclosure may be provided in various configurations. Any variety of suitable materials of construction, configurations, shapes and sizes for the components and methods of connecting the components may be utilized to meet the particular needs and requirements of an end user. It will be apparent to those skilled in the art that various modifications can be made in the design and construction of such a modular rotor assembly without departing from the scope of the attached claims, and that the claims are not limited to the preferred embodiments illustrated.
