1. Field
Various embodiments disclosed herein relate generally to centrifugal overhung pumps, including but not limited to horizontal and vertical inline pumps such as API standards classifications OH1, OH2, and OH3.
2. Related Art
Current centrifugal overhung pumps include components and designs to help maximize operating efficiencies of the pumps, including avoiding excess operational temperatures. However, present devices contain a variety of limitations and disadvantages.
Centrifugal overhung pumps, such as horizontal and vertical inline pumps, have a variety of applications and can be used, for example, in petroleum or refinery processes, petrochemical processes, gas processing, coal processing, and/or slurry and solids handling. Overhung pumps can also be configured for use with a variety of API processes, and can be adapted to meet the requirements of API standards, such as API 610, API 682, and other standards, such as HI and ANSI standards.
Various embodiments of overhung pumps include an impeller at one end of the pump that may help drive movement of a material. The impeller is typically within a pump housing. Pumps often include a bearing housing connected to the pump housing. The bearing housing can include a bracket portion that can be used to attach the bearing housing to the pump housing. The bearing housing can also include a cradle portion that can retain a plurality of bearings, which help allow for rotation of a shaft that drives the impeller. Many processes are performed at high temperatures such that the impeller receives a significant amount of heat from the material it pumps. Other sources of heat, such as friction, may also heat the impeller.
It is frequently desirable to help minimize the operational temperatures of various portions and components of overhung pumps. Bearings, for example, can have an increased lifespan when they operate at lower temperatures. Additionally, various regulations, safety concerns, or operational concerns may require that portions of the pump remain below certain temperatures. Thus, various pumps include designs to help cool the pump, and in particular the bearing housing, such as by promoting heat transfer away from the pump and bearing housing. In some instances, this can be accomplished by including a shroud around at least a portion of the pump and a fan to help drive air along the body of the pump, promoting convection heat transfer. In some instances, cooling water can be run over a portion of the pump. Both of these cooling techniques, however, require additional expense in the form of energy output and/or the necessity for additional components. Additionally, in the case of cooling water, regulations often require the water to be filtered before it can be dumped. This is commonly done by reverse osmosis or other processes that can be quite expensive. Thus, a pump design, or a design for various components of the pump, that can help maximize efficient cooling of the pump can help minimize operational costs for many pump procedures.
Various embodiments described herein relate to an improved bearing housing that dramatically limits heat transfer from the bracket of the bearing housing to the cradle of the bearing housing and that improves cooling of the bracket. This can significantly decrease operating temperatures within the cradle relative to current bearing housing designs. Various embodiments described herein include a bearing housing with a gap separating the cradle from the bracket. A plurality of ribs can connect the cradle to the bracket across the gap. This can improve the ability of the bracket to cool. It can also minimize heat transfer from the bracket to the cradle.
In various embodiments, bridging ribs between a cradle and a bracket of a bearing housing serve to isolate bearings from heat of a pump. The ribs also create additional surface area for heat to escape in form of convectional and radiant heat loss. In addition, in some embodiments hollow channels that pass through lubricating oil or a lubricant reservoir allow for additional air cooling. These various features can in some embodiments eliminate the need for a cooling fan and/or cooling water.
In various embodiments, a centrifugal overhung pump can include a shaft defining a longitudinal axis of the pump, the shaft having a proximal end and a distal end; an impeller at the distal end of the shaft; a pump housing having an inlet and an outlet, wherein at least a portion of the impeller is within the pump housing; and a bearing housing attached to the pump housing. The bearing housing can include a central channel that receives at least a portion of the shaft, a distal portion that is attached to the pump housing and that includes a distal face and a proximal face, and a proximal portion that houses a plurality of bearings between an outer wall of the proximal portion and the shaft and that includes a distal face and a proximal face. A plurality of ribs can connect the distal portion to the proximal portion, the ribs defining a gap between the proximal face of the distal portion and the distal face of the proximal portion.
In some embodiments, the pump housing can include a pump casing and a casing cover. In some embodiments, the bearing housing can include a length from the distal face of the distal portion to the proximal face of the proximal portion, the ribs can have a length, and the ratio of the width to the length width can be between approximately 20 and approximately 40. In some embodiments, the bearing housing can be formed monlithically. In some embodiments, the plurality of ribs can all either be generally horizontally aligned or generally vertically aligned. In some embodiments, a heat sink can be positioned about the shaft. The heat sink can include a plate that is positioned entirely between the distal portion of the bearing housing and the proximal portion of the bearing housing. In some embodiments, a lubrication ring that has a circumferential notch on its outer surface can be positioned around the shaft. In some embodiments, the lubrication ring can also have a chamfer on either side of its outer surface. In some embodiments, the bearing housing can include an oil reservoir and an enclosed cooling channel can pass through the reservoir, with opposite ends of the enclosed cooling channel communicating with an exterior of the bearing housing.
In various embodiments, a bearing housing for use with a centrifugal pump can include a first portion having an outer wall that defines an interior of the first portion, a first end that is configured to attach to a pump casing, and a second end opposite the first end. The first portion can be configured to receive a pump shaft inserted through the bearing housing and that passes through the first end and the second end. The bearing housing can also include a second portion adapted to house a plurality of bearings and positioned adjacent the first portion. The second portion can have a first side and a second side opposite the first side, the first side closer to the second end than the second side is to the second end, and when the pump shaft is inserted through the bearing housing the pump shaft can pass through the first side and the second side. The bearing housing can also include a gap separating the first portion and the second portion and a plurality of ribs extending across the gap and joining the first portion and the second portion. In some embodiments, the bearing housing can also include an oil reservoir and an enclosed cooling channel that passes through the reservoir.
In some embodiments, the second portion can include a plurality of exterior ridges configured to assist in heat transfer from the second portion. In some embodiments, at least some of the exterior ridges are also ribs extending across the gap and joining the first portion and the second portion. In some embodiments, the bearing housing can include an oil reservoir within the second portion. In some embodiments, an enclosed cooling channel can pass through the oil reservoir and can communicate with an exterior of the second portion.
In various embodiments, a bearing housing for use with a centrifugal pump can include a bracket configured to connect the bearing housing to a pump housing and to receive a portion of a pump shaft passing through the bearing housing, a cradle configured to retain a plurality of bearings between an outer wall of the cradle and a portion of the pump shaft passing through the bearing housing, and a connecting section joining the cradle and the bracket, the connecting section having an outer wall that defines an interior space configured to receive a portion of the pump shaft passing through the bearing housing, and a plurality of slots extending through the outer wall to the interior space to allow airflow through the interior space. In some embodiments, the bearing housing can include an oil reservoir. In some embodiments, an enclosed cooling channel can pass through the oil reservoir and can communicate with an exterior of the oil reservoir.
Various embodiments described herein also relate to an improved lubrication or flinger ring, which can be used to ensure a consistent spread of oil within a bearing housing. Flinger rings are generally positioned about a pump shaft and have a section within a lubricant reservoir of a bearing housing. The rings rotate with the shaft and spread lubricant from the reservoir within the bearing housing. In various embodiments, flinger rings can have different cross-sectional profiles that lead to more stability as they rotate and improved distribution of lubricant.
Various embodiments described herein relate to designs of pumps and pump components that can help maximize cooling from an end of the pump that receives a material to an end of the pump that houses bearings in a shaft of the pump. Although various embodiments may be illustrated and discussed with respect to overhung pumps, it is understood that they may equally apply to inline pumps.
The bearing housing 100 preferably includes a first portion or bracket 110 at a distal end of the housing and a second portion or cradle 120 toward a proximal end of the housing. In some embodiments the bearing housing can be formed monolithically. In some embodiments, the bracket and cradle can be formed separately. The bracket can be adapted to provide access to bolts 2 or other attachment mechanisms that help retain the bearing housing to the pump housing. In some embodiments, the bracket can also retain a seal, such as a mechanical seal, that can seal with the pump housing.
In some embodiments, a bearing housing can also have components configured to help provide lubrication to the shaft and/or the bearings. Thus, for example, in some embodiments a bearing housing can include a lubricant or oil reservoir 50. In some embodiments, an “oil level” line can be provided on the outside of the oil reservoir, such as by being cast as part of the bearing housing. One or more lubrication or flinger rings 60 can be positioned around the shaft and can rotate with the shaft. One end of the flinger rings can be within the lubricant, and as they rotate with the shaft the flinger rings can help distribute the lubricant within the bearing housing. In various embodiments, the flinger rings can have particular profiles that can help maximize their ability to distribute lubricant and to rotate efficiently about the shaft. In some embodiments, as described in more detail below, the lubricant reservoir 50 can include one or more cooling channels 52 that pass through the lubricant reservoir and can help cool the lubricant. The cooling channels can have openings on either end that communicate with an exterior of the bearing housing to allow air to flow through the channels.
In some embodiments, the pump assembly 10 can include a heat sink 70 positioned between the cradle 120 and the distal end of the bearing housing 100. The heat sink can help minimize temperatures within the cradle, such as at the bearings, by absorbing a portion of the heat that flows from the pump housing toward the bearing housing and shaft.
The cradle 120 can include a first or distal end 122 and a second or proximal end 124. In some embodiments, the cradle can also include a plurality of cradle ribs or fins 126, which can help maximize heat transfer from the cradle to the environment. Preferably, the cradle includes ribs on at least both sides and the top of the cradle.
In some embodiments, the bridging ribs 132 can be considered to define an outer wall 131 of a connecting section between the bracket 110 and the cradle 120. Openings or slots 133 can pass to an interior of the connection section. In some embodiments, such as shown in
In some embodiments, the openings or slots 133 can comprise varying percentages of the total outer surface area of the outer wall 131 of the section connecting the bracket 110 and the cradle 120. For example, a percentage of 0% would indicate that the outer wall 131 lacks a single opening 133. A percentage of 100% would indicate that there is no outer wall surface. In some embodiments, openings 133 can be at least 20% of the total surface area of the outer wall 131. In some embodiments, openings 133 can be at least 30% of the total surface area of the outer wall 131. In some embodiments, openings 133 can be at least 50% of the total surface area of the outer wall 131. In some embodiments, openings 133 can be at least 70% of the total surface area of the outer wall 131.
Referring to
In some embodiments, as illustrated in
In some embodiments, the bridging ribs 132 can include side bridging ribs 134 and top and bottom bridging ribs 136. In some embodiments, the bearing housing 100 can include just side ribs, just top ribs, just bottom ribs, or just top and bottom ribs. In some embodiments, the side ribs 134 can be shaped and/or configured differently from the top and bottom ribs 136. For example, in some embodiments, as illustrated, side bridging ribs 134 can all have approximately the same profiles and dimensions. In some embodiments, these profiles and dimensions can be different from top and bottom ribs 136. In some embodiments, each side rib 134 can have the same size and dimension of an opposite side rib. In some embodiments, side ribs 134 and/or top and bottom ribs 136 can be narrower at an outer end of the ribs than they are at an inner end of the ribs. Thus, for example, in some embodiments, the gaps 135 between the side ribs can narrow as the gaps get closer toward the opening 152 in the distal cradle face. Similarly, in some embodiments the gaps 137 between the upper ribs can narrow as the gaps get closer toward the opening 152 in the distal cradle face 150.
In various embodiments, the upper and lower ribs 136 can be generally vertically oriented, and the side ribs 134 can be generally horizontally oriented, such as illustrated. In some embodiments, all of the bridging ribs 132 can be radially aligned. In other words, in some embodiments each of the ribs can be aligned with a radius extending from a longitudinal axis of the bearing housing.
In some embodiments, efficient cooling of the bearing housing can depend upon the size of the gap 130 between the bracket 110 and cradle 120 relative to the thickness t1 of the outer wall 116 of the bracket 110. In some embodiments, the ratio of the thickness t1 to the gap width w4 can be between approximately 1 and approximately 6. In some embodiments, the ratio of the thickness t1 to the gap width w4 can be between approximately 2 and approximately 5. In some embodiments, the ratio of the thickness t1 to the gap width w4 can be between approximately 2.5 and approximately 3.5.
In various embodiments, it can be desirable to have a bearing housing 100 with natural structural frequencies that differ from operating frequencies of pumps that may be used with the bearing housing. Many pumps operate at different rotational speeds between 20 Hz and 60 Hz. Thus, for example, it may be desirable for a bearing housing to have a natural frequency that is outside of that range. This prevents potential vibration problems and can allow the bearing housing to be used with a greater variety of pumps. Various embodiments described herein have a natural frequency greater than approximately 200 Hz. In some embodiments, a bearing housing 100 may have a natural frequency greater than approximately 300 Hz. In some embodiments, a bearing housing 100 may have a natural frequency greater than approximately 400 Hz. In some embodiments, a bearing housing 100 may have a natural frequency approximately equal to 433 Hz. In some embodiments, a bearing housing 100 may have a natural frequency greater than approximately 440 Hz.
In some embodiments, the dimensions of the gap and/or ribs can affect the natural structure frequency of the bearing housing. For example, in some embodiments the gap can have a width w4 (shown in
In some embodiments, as described above, flinger rings can be used to distribute lubricant within the bearing housing.
In various embodiments, the size of the notch 64 can affect how well the ring distributes oil. Thus, for example, in some embodiments, the width of the ring w5 relative to the width of the notch w6 can effect oil distribution. For example, in some embodiments the ratio of the width w5 of the ring to the width w6 of the notch can be between approximately 1.5 and approximately 5. In some embodiments, the ratio of the width w5 of the ring to the width w6 of the notch can be between approximately 2 and approximately 4. In some embodiments, the ratio of the width w5 of the ring to the width w6 of the notch can be between approximately 2.5 and approximately 3.5. In some embodiments, the ratio can be approximately 3.
Similarly, in some embodiments, the width of the notch w6 relative to its depth d1 can affect oil distribution. In some embodiments, the ratio of w6 to d1 can be between approximately 0.75 and approximately 2. In some embodiments, the ratio can be between approximately 1 and approximately 1.5.
In some embodiments, the ring 60 can also include a chamfer 66 on either side of its outer surface. In some embodiments, the size of the chamfer d2 can be defined relative to the depth d1 of the notch 64. In some embodiments, d2 can be less than d1, as illustrated. In some embodiments, d2 can be greater than d1. In some embodiments, the ratio of the depth d1 of the notch 64 to the size of the chamfer d2 can be between approximately 2 and approximately 4. In some embodiments, it can be between approximately 2.5 and approximately 3.5.
In some embodiments, an inner wall of the ring 60 can include one or more rectangular notches 62. The rectangular notches can help the inner ring maintain stability as it rotates with the shaft of the pump assembly. This can help generate a more constant flow of lubricant and a more consistently placed flow of lubricant within the lubricant reservoir 50.
The terms “approximately”, “about”, and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount.
Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above.
Similarly, this method of disclosure is not to be interpreted as reflecting an intention that any claim require more features than are expressly recited in that claim. Rather, inventive aspects may lie in a combination of fewer than all features of any single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment.
Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. This application is related to and claims priority to U.S. Provisional Application No. 61/786,061, filed Mar. 14, 2013, the entire application of which is hereby incorporated by reference and made a part of this specification.
Number | Date | Country | |
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61786061 | Mar 2013 | US |