Patent Application
20160341208
This disclosure relates, in general, to centrifugal pumps and, in particular, to improved apparatus for carrying out the adjustment of elements of a seal mechanism of a centrifugal pump while the pump is in operation.
Centrifugal pumps conventionally include an impeller that is positioned within a pump chamber for rotation. The pump chamber is generally formed within outer casing elements which, in combination, form a pump casing having a suction inlet and a pump discharge. A drive shaft extends into an opening in the pump casing to engage and be secured to the impeller for rotation of the impeller. The drive shaft is attached to a drive means, such as a motor, and is typically supported by a bearing assembly.
A seal mechanism or seal assembly is typically positioned between the impeller and the pump casing in the area of the opening through which the drive shaft is received in the pump casing to lessen or prevent the leakage of fluid from the pump casing. The seal mechanism or seal assembly is typically positioned about the drive shaft at the point of entry of the drive shaft into the pump casing.
Various types of seal mechanisms have been developed for use in pumps and include dynamic seals, mechanical seals and gland seals. Dynamic seals comprise dry seals that function only during the operation of the pump and in the presence of secondary seals, such as lip seals or packing rings, that are positioned in proximity to the dynamic seals to prevent or limit fluid leakage from the pump casing when the pump is not in operation (i.e., the impeller is not rotating). Mechanical seals comprise a rotating seal and a stationary seal, each having a seal face that, in combination, seal the area from fluid leakage. Gland seals usually comprise a plurality of packing rings or similar elements that are retained in a housing or sleeve. The packing rings are held in compression within the seal housing to prevent leakage. The area of the packing rings is constantly maintained with lubricating fluid that keeps the packing rings cooled and lubricated.
Proper initial alignment and periodic adjustment of seal devices is required in order to maintain proper operation of the pump and to avoid or lessen fluid leakage in and around the seal. To that end, various seal adjustment devices have been developed which are directed to either statically or dynamically adjusting the seal devices of the sealing mechanism.
Although adjustment of the seal elements of the seal mechanism can be accomplished while the pump is not in operation, it is more frequently a requirement that the seal elements be dynamically adjusted, or adjusted while the pump is in operation. This is especially true in certain seal arrangements where the seal devices need to be periodically adjusted in the initial operational hours or days of the pump until the seal devices achieve a desired level of sealing. For example, in certain seal assemblies, some amount of leakage is permissible in order to lubricate the seals. However, an excessive amount of leakage is undesirable and can result in dissipation of limited fluid resources and environmental pollution. Consequently, periodic adjustment of the seal assembly is needed during operation of the pump to keep the level of fluid leakage at a permissible rate.
Adjustment of the seal elements while the pump is in operation provides certain concerns and difficulties. One major concern is the necessity of making the adjustments in close proximity to the rotating elements of the pump. Serious injury can occur if contact is made by humans with the rotating drive shaft and other rotating elements of the pump. Consequently, many industrial pump operators elect not to make necessary seal adjustments in order to avoid having to come into proximity with the rotating elements of the pump. As a result, pump efficiencies are sacrificed leading to poor operation, excessive consumption or loss of lubricating fluid and early deterioration of the seal mechanism.
Of further concern is the fact that seal adjustment devices have, to date, proven to be insufficient for, or incapable of, making accurate adjustment of the seal elements. While known seal adjustment devices can cause some movement of, or can adjust, the seal elements (e.g., static seals in a mechanical seal arrangement or packing seals), the movement is often not axially accurate and misalignment of the seal elements with other elements of the seal or pump can produce failure of the seal. For example, misalignment of a static seal and a dynamic seal can cause the seal faces to join improperly and thus be subject to premature wear, or can result in incomplete sealing and undesirable leakage at the seal face.
Additionally, conventional seal assembly adjustment devices are limited in the amount of adjustment they can provide. For certain seal assemblies, such as gland assemblies, the nature of the sealing elements, such as packing rings, necessitates a larger axial adjustment than is required in other types of seal arrangements, such as mechanical seals. Conventional seal adjustment devices are limited, by virtue of their design, in the amount of axial adjustment that can be provided to the seal assembly.
Therefore, providing a seal adjustment device that produces accurate axial movement and alignment of the seal elements is beneficial. It is further advantageous to provide a seal adjustment device which can be actuated at a distance from the rotating elements of the pump so that proper and dynamic adjustment can be safely made.
In a first aspect, embodiments are disclosed of a seal adjustment system for a centrifugal pump that includes a movable arm having two opposing ends, one end being positioned relative to a sealing mechanism of a pump and the other end being arranged for connection to a portion of the pump spaced from the sealing mechanism, and an adjustment mechanism having a first end positioned for attachment to a portion of a pump and a second end connected to the other end of the movable arm in articulating engagement therewith, wherein activation of the adjustment mechanism provides movement of the movable arm to effect adjustment of a portion of the sealing mechanism of the pump. This seal adjustment system is advantageous over known adjustment systems by compensating for angular misalignments that may occur in adjustment of the system, thereby providing accurate and properly aligned movement of the seal elements of the seal mechanism. This seal adjustment system also provides axial adjustment of the seal assembly to a degree unachievable by conventional adjustment devices.
In certain embodiments, the seal adjustment system further includes one or more angular compensation devices positioned between the other end of the movable arm and the portion of the pump to which it is connected by the adjustment mechanism to compensate for angular movement of the movable arm relative to the sealing mechanism.
In certain other embodiments, the connection of the movable arm to the adjustment mechanism further includes an angular compensation device.
In still other embodiments, the adjustment mechanism is connected to the pump by an articulating element.
In certain embodiments, the articulating element is structured to provide angular compensation to movement of the movable arm.
In some embodiments, the adjustment mechanism may be actuated to move the movable arm by operation of a hydraulic apparatus.
In other embodiments, the adjustment mechanism further includes a length-adjustable device structured to provide variable adjustment of the distance between the first end of the adjustment mechanism and the second end of the adjustment mechanism to provide movement of the movable arm relative to the portion of the pump to which the adjustment mechanism is connected.
In certain embodiments, the length-adjustable device includes a turnbuckle.
In certain other embodiments, the length-adjustable device includes a threaded rod positioned at one end for connection to an attachment member that is secured to said portion of the pump, and a block having an aperture for receiving a threaded end of the threaded rod therethrough, the block having an engagement end for articulating connection to the said other end of the movable arm.
In yet other embodiments, at least one locking element is provided for locking the position of the block relative to the threaded rod following activation of the adjustment mechanism.
In still other embodiments, a threaded pin is threadingly received in one end of the threaded rod, the threaded pin having a head end structured for articulating connection to the attachment member.
In certain embodiments, a locking nut is positioned between the threaded pin and the threaded rod for securing the position of the threaded pin relative to the threaded rod.
In some embodiments, the one end of the movable arm has attached thereto a drive member having a contact surface that engages a portion of a sealing mechanism to effect axial adjustment of a portion of the sealing mechanism.
In certain other embodiments, the drive member comprises a ring element that is positioned to be coaxial with the drive shaft of a pump.
In still other embodiments, the ring element is comprised of two semi-circular halves that are connected together to be coaxially positioned about a drive shaft.
In yet other embodiments, the sealing mechanism includes packing elements and the drive member is positioned relative to the packing elements to effect axial adjustment of the packing elements.
In certain embodiments, the movable arm is further secured at a point between the two opposing ends thereof to stabilize the movable arm relative to the pump and to provide a point of pivotal movement of the movable arm thereabout.
In yet other embodiments, the point between the two opposing ends of the movable arm is provided with an angular compensation element to compensate for angular movement of the movable arm.
In a second aspect, a seal adjustment device for use with the seal mechanism of a pump includes a movable arm, a drive member joined to the movable arm for articulating movement therewith, the drive member having a contact surface for contacting part of a sealing mechanism, an adjustment mechanism articulatingly connected to the movable arm at a distance from the drive member, and a stabilizing element positioned on the movable arm between a point of attachment of the movable arm to the adjustment mechanism and a point of attachment of the movable arm to the drive member. This seal adjustment device provides an advantage over conventional seal adjustment devices in having the ability to compensate for angular alignments or misalignments that may occur during adjustment of the seal mechanism and to provide greater axial adjustment of the elements of the seal assembly.
In certain embodiments, the seal adjustment device further includes an attachment member configured to provide for connection of the adjustment mechanism to a portion of a pump.
In other embodiments, the seal adjustment device further includes at least one angular compensation element positioned between the adjustment mechanism and the movable arm.
In yet other embodiments, the movable arm further includes a first end connected to the adjustment mechanism and a second end that engages with the drive member, the second end being U-shaped and having opposing terminal ends that pivotally engage the drive member.
In certain embodiments, the terminal ends are configured with slots in which a connecting pivot pin is received.
In still other embodiments, the drive member is a ring sized to be received in coaxial arrangement with a drive shaft of a pump.
In certain embodiments, the ring is comprised of two semi-circular halves which are arranged and secured together.
In yet other embodiments, the adjustment mechanism is a length-adjustable apparatus.
In certain embodiments, the length-adjustable apparatus comprises a threaded element having a first end connected to the attachment member and a second end connected to the movable arm, the threaded element defining an adjustable length that extends between the first end of the threaded element and the second end of the threaded element, wherein manipulation of the threaded element effects an adjustment of the distance between the attachment member and the movable arm.
In certain other embodiments, the threaded element comprises a turnbuckle having opposing ends which are respectively attached to the attachment member and the movable arm.
In still other certain embodiments, the threaded element further includes a threaded rod, affixed at one end to the attachment member, and a block having an aperture for receiving a threaded end of the threaded rod therethrough, the block having an engagement end for articulating connection to the movable arm.
In some embodiments, the threaded element is connected to the movable arm by an angular compensation device.
In a third aspect, a centrifugal pump has a pump casing defining a pump chamber with an impeller positioned within the pump chamber, the impeller being connected to a drive shaft that is positioned through a bearing assembly, and having a seal mechanism positioned between the drive shaft and the pump casing, the centrifugal pump further having a seal adjustment device for effecting adjustment of a portion of the seal mechanism, the seal adjustment device including a movable arm having two opposing ends, one end being positioned relative to a seal mechanism of a pump and the other end being arranged for connection to a portion of the pump spaced from the seal mechanism, an adjustment mechanism having a first end positioned for attachment to a portion of a pump and a second end connected to said other end of the movable arm in articulating engagement therewith, and wherein adjustment of the other end of the movable arm relative to the portion of the pump to which it is connected causes movement of the one end of the movable arm relative to the seal mechanism to effect an adjustment of a portion of the sealing mechanism. The centrifugal pump of this aspect provides adjustment of elements of the seal mechanism while compensating for angular alignments or misalignments that may occur during the adjustment operation.
In certain embodiments, the seal adjustment device of the centrifugal pump further includes a drive member that is operatively attached to the movable arm and is positioned in contact with a portion of the seal mechanism to effect an axial adjustment of a portion of the seal mechanism upon adjustment of the movable arm.
In other embodiments, the seal adjustment device further includes at least one angular compensation mechanism positioned between the attachment of the adjustment mechanism to the pump and the attachment of the adjustment mechanism to the movable arm.
In still other embodiments, a shield is positioned about the drive shaft to provide a safety barrier about the drive shaft, wherein the adjustment mechanism is positioned outside of the shield and is accessible for manipulation to effect adjustment of the movable arm.
In a fourth aspect, a method of adjusting a seal mechanism of a centrifugal pump that is positioned between the pump casing of the pump and the drive shaft of the pump includes the operations of providing a seal adjustment system that is positioned in contact with the seal mechanism of the pump to effect axial movement of a portion of the seal mechanism, where the seal adjustment system includes a movable arm having two opposing ends, one end being positioned relative to the seal mechanism of the pump and the other end being operatively connected to an adjustment mechanism by articulating attachment, the adjustment mechanism being attached to a portion of the pump and provides adjustment of the said other end of the movable arm relative to the portion of the pump to which the adjustment mechanism is attached, and actuating the adjustment mechanism of the seal adjustment system to effect movement of the movable arm by adjusting the length of the adjusting mechanism and causing the movable arm to pivot at the point of connection of the movable arm to the adjustment mechanism. An advantage of this aspect is to provide operative steps for adjusting the seal mechanism of a centrifugal pump in a manner that compensates for angular movements or misalignments that may occur in adjusting the sealing elements.
In certain embodiments of this aspect, the seal adjustment device further includes a drive member operatively attached to the movable arm and positioned in contact with a portion of the seal mechanism, and movement of the movable arm effected by the actuation of the adjustment mechanism causes axial movement of the drive member against a portion of the seal mechanism.
In a fifth aspect, a method of fitting a seal adjustment device to a centrifugal pump includes the operative steps of providing a centrifugal pump having a pump casing defining a pump chamber, the pump casing having an opening through which a drive shaft is received, a bearing assembly positioned to support the drive shaft, and having a seal mechanism positioned between the drive shaft and the pump casing, providing a seal adjustment device comprising a movable arm, having two opposing ends, and an adjustment mechanism that is operatively connected to the movable arm, attaching the adjustment mechanism to a portion of the centrifugal pump, attaching the movable arm to the adjustment mechanism to be articulating therewith, and positioning the movable arm in proximity to a portion of the seal mechanism to effect axial movement of a portion of the seal mechanism when the adjustment mechanism is actuated to cause movement of the movable arm. The advantage of this aspect is to provide means for retrofitting existing pumps with an improved seal adjustment device that provides compensation of angular misalignment in axial adjustment of elements of the seal mechanism.
In certain embodiments of this aspect, the operative steps further include providing a drive member operatively connected to the movable arm and positioning the drive member about the drive shaft and in contact with a portion of the seal mechanism to effect axial movement of a portion of the seal mechanism upon movement of the movable arm.
In still other embodiments of this aspect, the operative steps further include positioning the adjustment mechanism at a distance from the drive shaft.
In a sixth aspect of the disclosure, a kit for providing a seal adjustment mechanism for a centrifugal pump includes a drive member having a contact surface for placement in contact with a seal mechanism of a pump, a movable arm having two opposing ends, one end being structured for attachment to the drive member and the other end being arranged for connection to a portion of the pump spaced from the sealing mechanism, and an adjustment mechanism having a first end positioned for attachment to a portion of a pump and a second end connected to said other end of the movable arm in articulating engagement therewith.
In some embodiments of this aspect, the kit may further include a shield device structured for positioning in proximity to the drive shaft of a pump.
Other aspects, features and advantages will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of the inventions disclosed.
The accompanying drawings facilitate an understanding of the various embodiments.
In certain centrifugal pumps, and as shown in
As further illustrated in
A seal adjustment system 30 for a centrifugal pump, in accordance with the disclosure, is positioned relative to the seal assembly 26 to effect axial adjustment of elements of the seal assembly 26 when the pump is in operation. The detailed construction of exemplar embodiments of the seal adjustment system 30 are described further below. However, for the sake of understanding the advantages of the seal adjustment system 30 of this disclosure,
Specifically,
An access region 48 is defined between the support member 36 and the pump casing 12, which is spanned by the mounting member 42. Within the access region 48 is a portion of the rotating drive shaft 24 and other rotating elements. The access region 48 provides means for effecting necessary adjustment to elements of the seal assembly 26 as described further below, but also exposes rotating elements of the pump, which poses a danger. Therefore, a safety shield 50 is positioned to prevent direct exposure of humans to the rotating elements.
With reference to
The seal adjustment system 30 is configured such that activation of the adjustment mechanism 70 provides movement of the movable arm 60 to effect axial adjustment of a portion of the sealing mechanism 52. For example, the seal adjustment system 30 may be connected to the shaft sleeve to effect movement of a seal ring or other device connected to the shaft sleeve. In other embodiments, the seal adjustment system 30 may be connected to one or a series of packing rings of a gland system, or to an intermediary device such as a packing housing that imposes compression on the packing rings. These arrangements are by way of example only and other arrangements are possible whereby the seal adjustment system 30 effects axial adjustment or movement of elements of a seal mechanism.
Further, while
The provision of one or more angular compensation elements or devices in the seal adjustment system 30 of the disclosure presents an advantage over prior known seal adjustment mechanisms. Prior devices are oftentimes inefficient or ineffective in providing accurate axial movement of elements of the sealing mechanism, thereby resulting in poor sealing and consequent leakage. This is because the typical configuration of prior devices limits or constrains the movement of the seal adjustment mechanism which results in non-linear or angular movement of the seal elements in the seal assembly and poor sealing results. The one or more angular compensation devices, as described further herein, assure that movement and adjustment of the elements of the seal mechanism are accurate to assure effective sealing in the seal mechanism following dynamic adjustment. As used herein, “angular compensation” refers to compensation for angular variations that may occur between two structural elements that are joined together by an axis point providing articulation of one structural element relative to the other structural element, the angular variations resulting in one structural element moving at or to an angle relative to the other structural element.
With reference to
Further, the seal adjustment system 30 may include an attachment device 88, such as a clevis block 90, that is secured to a portion 68 of the pump 10 by screws inserted into holes 92 formed in the attachment device 88. The first end 72 of the adjustment mechanism 70 may be connected to the attachment device 88 by a pivot point 82, and the first end 72 may be formed as a ball joint that articulates with the attachment device 88 to provide angular compensation for movement of the adjustment mechanism 70 and movable arm 60. The ball joint ends of the adjustment mechanism 70 may include a coating that facilitates articulation of the ball joints relative to their respective points of attachment. Such coatings may include lubricants or deposition coating of a material such as PTFE.
The adjustment mechanism 70 may further comprise a length-adjustable device 100 that is structured to provide variable adjustment of the distance D between the first end 72 of the adjustment mechanism 70 and the second end 74 of the adjustment mechanism 70 to provide movement of the movable arm 60 relative to the portion 68 of the pump 10 to which the adjustment mechanism 70 is connected. In the embodiment of the seal adjustment system 30 shown in
The one end 62 of the movable arm 60 is connected to a drive member 108 that has a contact surface 110 which is oriented to engage a portion of a sealing mechanism to effect axial adjustment of a portion of the sealing mechanism as previously described. As best seen in
As depicted in the drawings, the drive member 108 may be a ring 112. Moreover, the ring 112 may be comprised of two semi-circular halves 114, 116 that are joined together, such as by a bolt 118, to position the drive member 108 about the drive shaft 24 when being assembled. The drive member 108 is provided with an inner surface 120 that is oriented toward the drive shaft 24 of the pump 10.
The one end 62 of the movable arm 60 is configured to accommodate connection of the drive member 108 thereto. For example, the one end 62 is formed as a U-shaped member 124 having spaced apart terminal ends 126, 128 to which the drive member 108 is articulatingly attached. The terminal ends 126, 128 are, for example, connected to the drive member 108 by pivot pins 130, 132 which allow the drive member 108 to move relative to the movable arm 60. The pivot pins 130, 132 are received in slots 220, which are described more fully below.
In the seal adjustment system 30, the movable arm 60 is further secured at a point 136 between the two opposing ends 62, 64 thereof to stabilize the movable arm 60 relative to the pump 10 and to provide a point of pivotal movement of the movable arm 60 thereabout. As generally seen in
Manipulation or activation of the adjustment mechanism 70 effects an adjustment of the distance between the other end 64 of the movable arm 60 and the portion 68 of the pump 10 to which the other end 64 of the movable arm 60 is ultimately connected. Movement or adjustment of the adjustment mechanism 70 in turn causes a pivoting of the movable arm 60 about the point 136 and movement of the one end 62 of the movable arm 60, which in turn effects articulating movement of the drive member 108 relative to the movable arm 60. The drive member 108 is consequently urged in an axial direction to effect axial movement or adjustment of a portion of the seal mechanism to which the drive member 108 is in contact.
The one or more angular compensation devices, which may take the form of ball joints, elongated slots or other configurations or devices, enable an accurate axial movement as described throughout this disclosure.
As illustrated best in
The threaded end pin 192 is adjustable relative to the threaded rod 166 by rotation of the threaded shaft 194 into and out of the threaded channel 190 (shown in phantom in
A threaded end 174 of the threaded rod 166 is received through the non-threaded aperture 172 formed in the block 170. Simultaneous rotation of the two locking nuts 206, 208 along the threaded rod 166 results in an increase or decrease of the distance between the position of the block 170 relative to the pump 10 or the attachment device 88.
Further adjustment of the adjustment mechanism 70 relative to the movable arm 60 is provided in the engagement end 180 of the block 170. The engagement end 180 may be configured with an adjustable pin 210 which is threadingly received in the block 170 at a generally perpendicular orientation to the axis of the aperture 172 of the block 70. The adjustable pin 210 has a head 212 which is positioned for connection to the other end 64 of the movable arm 60. The head 212 is preferably structured for providing articulating movement between the block 170 and the other end 64 of the movable arm 60. Most suitably, the head 212 is configured to provide angular compensation for the movement of the adjustment mechanism 70 and the movable arm 60. In one embodiment, the head 212 is formed as a ball joint to provide angular compensation of the movement of the adjustment mechanism 70 relative to the movable arm 60. Because the adjustable pin 210 is adjustable relative to the block 170, a locking nut 214 is provided to retain the positioning between adjustable pin 210 and the block 170.
The embodiment of the seal adjustment device 160 shown in
The increased travel and angular movement further enables an efficient and accurate axial movement of the drive member against the seal elements. The slots 220 in either terminal end 126, 128 of the movable arm 60 eliminate any binding of the pivot pin 222 within the slot 220 and allows greater axial distance of travel of the drive member 108. For example, conventional adjusting devices only provide axial movement of the seal elements in a range from two to three millimeters, while the present device provides from a small axial adjustment up to 35 mm to 75 mm of axial adjustment, depending on the size of the pump and seal assembly.
The mode by which the adjustment assembly of the seal adjustment system is moved or actuated has been described herein with respect to mechanical means, such as the turnbuckle 104 of
As depicted in
In a further aspect of this disclosure, a kit for providing a seal adjustment mechanism for a centrifugal pump may include a drive member having a contact surface for placement in engagement with a seal mechanism of a pump, a movable arm structured as described herein, and an adjustment mechanism for attachment to a portion of a pump and structured for connection to the movable arm in articulating engagement therewith. The kit may further include a shield device for attachment to the drive mechanism or pump, as described herein. The kit may provide those elements necessary to retrofit an existing pump, or to repair an existing pump, to enable adjustment of the seal mechanism of the pump in accordance with this disclosure.
In the foregoing description of certain embodiments, specific terminology has been resorted to for the sake of clarity. However, the disclosure is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes other technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as “left” and “right”, “front” and “rear”, “above” and “below” and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.
In this specification, the word “comprising” is to be understood in its “open” sense; that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear.
In addition, the foregoing describes only some embodiments of the inventions, and alterations, modifications, additions and/or changes can be made thereto without departing from the scope and spirit of the disclosed embodiments, the embodiments being illustrative and not restrictive.
Furthermore, inventions have described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the inventions. Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment.
This is a non-provisional application that claims priority to U.S. provisional application Ser. No. 62/163,771, filed May 19, 2015, the contents of which are incorporated herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62163771 | May 2015 | US |
