Packing stack carrier for paint and other fluid pumps

A packing assembly includes a clip configured to hold a packing stack in a desired arrangement on a longitudinal axis. The clip includes upper arms and lower arms through which the packing stack and slide laterally into and out of the clip. The upper arms and lower arms prevent radial movement of the packing stack and can further prevent axial movement of the packing stack relative to the clip. The clip facilitates installation of the packing stack on a piston by shifting the assembled packing stack axially onto the piston and then pulling laterally off of the packing stack while leaving the packing stack on the piston rod.

BACKGROUND

The present disclosure relates to piston pumps, and in particular sealing elements within the pumps.

Piston pumps are used to pump fluids, typically at high pressures. The pump elements disclosed herein are particularly well suited for pumping paint, finishes, and other coatings which are typically abrasive, viscous, and/or otherwise difficult to pump. Packings are used to facilitate forming a dynamic seal in such difficult to handle fluid applications.

Packings are rings of sealing material. A packing can be formed from leather, rubber, polymer (e.g., ultra high molecular weight polyethylene or UHMWPE), and/or synthetic material. Packings commonly have complementary cross sections, such as having U or V cross section shapes, to mate and stack upon one another. Packings are typically arranged in a stack, such as six or more packing rings mounted atop one another. Packings of different types can be arranged in an alternating arrangement, such as leather-synthetic-leather-synthetic-leather-synthetic or other combination.

Glands are rings (typically metal) which having complementally cross sectional profiles, such as having U or V projecting and recessed cross sectional shapes to mate and stack with the packings. A set of two glands are typically placed at both ends (top and bottom) of the stack of packings, bracketing the stack of packings. The glands can then be fixed to a component of the pump. The glands can retain the stack of packings within the pump.

Packings are used as dynamic sealing surfaces in which the packings either move with the piston or the piston moves relative to the packings. For example, a stack of packings can be mounted on a piston rod such that the packings move with the piston rod and slide along the inner surface of the bore of the cylinder. In other examples, a stack of packings can be mounted on the inside bore of a cylinder and are held static relative to the cylinder while the piston slides along the packings. In both examples, the packings seal between the cylinder and the piston to prevent leakage of fluid past the packings between the cylinder and the piston. When packings are used with double displacement pumps, two stacks of packings are commonly used. A first set of packings seal along the pump rod of the piston, commonly known as throat packings. A second set of packings seal along the piston head of the piston, commonly known as piston packings.

Packings can be difficult to handle and install, particularly when in a stacked arrangement. Within the pump, the packings are arranged coaxial and contacting one another, but can fall out of coaxial, contacting alignment when not secured in place. If one packing in a stack is not coaxially aligned with the rest of the packings in a stack, then the stack cannot be properly aligned within the cylinder and/or on the piston.

SUMMARY

According to one aspect of the disclosure, a clip for holding a stack of packing rings having a first stack end, a second stack end, and a central bore through both the first stack end and the second stack end, on a longitudinal axis. The clip includes a spine having a first end and a second end; a first bracket extending from the first end of the spine partially around the axis, the first bracket configured to hold the first stack end; and a second bracket extending from the second end of the spine partially around the axis, the second bracket configured to hold the second stack end. The first bracket and the second bracket define a side opening oriented to allow the packing stack to slide laterally relative to the axis and out from between the first bracket and the second bracket.

According to another aspect of the disclosure, a method includes sliding a packing assembly in a first axial direction and onto an end of a piston for a reciprocating fluid pump. The packing assembly includes a clip having at least one bracket defining a side opening; and a packing stack retained on the clip and held in axial alignment on a longitudinal axis by the at least one bracket of the clip. The method further includes shifting the clip laterally relative to the piston to disengage the packing stack from the clip through the side opening leaving the packing stack disposed on the piston.

According to yet another aspect of the disclosure, an assembly includes a packing stack formed from a plurality of packing rings dispose on a stack axis, and a clip configured to hold the packing stack. The packing stack includes a first stack end; a second stack end disposed opposite the first stack end; and a central bore extending through the plurality of packing rings between the first stack end and the second stack end. The clip includes a spine having a first end and a second end; a top portion extending partially around the axis from the first end of the spine; and a bottom portion extending partially around the axis from the second end of the spine. The top portion and the bottom portion define an axially extending side opening oriented to allow the packing stack to slide laterally relative to the axis into and out of an area defined between the top portion, the bottom portion, and the spine.

DETAILED DESCRIPTION

Pump10reciprocates piston12within cylinder14to pump various fluids, examples of which include paint, water, oil, stains, finishes, aggregate, coatings, and solvents, amongst other options. Pump10can generate high fluid pumping pressures, such as 3,000-5,000 pounds per square inch (psi) or even higher. High fluid pumping pressure is useful for atomizing the fluid into a spray for applying the fluid to a surface.

Piston12is disposed within cylinder14and configured to reciprocate within cylinder14. First end26extends out of cylinder14through throat packings20b. Rod head30is disposed outside of cylinder14and is configured to connect to a drive system that drives reciprocation of piston12. Piston head24is connected to second end28of piston rod22. Piston head24can be connected to piston rod22in any desired manner, such as by interfaced threading or welding. In other examples, piston head24is integrally formed with piston rod22, such that piston rod22and piston head24form a unitary assembly. Check valve16bis disposed within piston rod22. In the example shown, piston head24retains check valve16bwithin piston rod22.

Intake housing32is connected to the bottom of cylinder14. In some examples, intake housing32is threadedly connected to cylinder14. Check valve16ais disposed within intake housing32and forms a one-way check valve to allow fluid to flow downstream into intake housing32while preventing the fluid from flowing upstream out of intake housing32.

Retaining nut18is located at an opposite end of pump10from intake housing32. Retaining nut18is secured to cylinder14and is configured to retain packing stack20bwithin cylinder14. Retaining nut18can be secured to cylinder14in any desired manner, such as by interfaced threading. Packing stack20bis disposed within cylinder14. Piston rod22extends through packing stack20band can reciprocate relative to packing stack20b.

Packing stack20bis configured to seal between piston rod22and the inner wall of cylinder14. Packing stack20ais disposed within cylinder14between piston12and cylinder14. Packing stack20ais configured to seal between piston12and the inner wall of cylinder14.

Piston12reciprocates within cylinder14to increase and decrease the volumes of both upstream chamber15and downstream chamber17. Increasing and decreasing the volumes of upstream chamber15and downstream chamber17draws fluid into cylinder14and pumps the fluid downstream out of cylinder14. During an upstroke, upstream chamber15expands creating suction and causing check valve16ato open, while downstream chamber17shrinks, thereby causing check valve16bto close and driving the fluid out of downstream chamber17. During a downstroke, upstream chamber15shrinks, thereby causing check valve16ato close, while downstream chamber17expands, opening check valve16band causing the fluid to flow from upstream chamber15to downstream chamber17through check valve16band piston rod22. The fluid enters downstream chamber17through outlet19formed though piston rod22. Pump10can be a double displacement pump such that piston12drives fluid downstream out of cylinder14during both the upstroke and the downstroke.

For each of packing stack20band packing stack20a, packings36a,36bare arrayed between glands34a,34b. Packings36a,36band glands34a,34bcan be of any desired size and in any desired arrangement for suitably sealing around piston12during reciprocation of piston12. Packings36a,36bare rings of sealing material and can be formed from leather, rubber, polymer (e.g., ultra high molecular weight polyethylene or UHMWPE), and/or synthetic material. Packings36a,36bcommonly have complementary cross sections, such as having U or V cross section shapes, to mate and stack upon one another. Packings36a,36bare typically arranged in a stack, such as six or more packing rings mounted atop one another. Packings36a,36bof different types can be arranged in an alternating arrangement, such as leather-synthetic-leather-synthetic-leather-synthetic or other combinations. Glands34a,34bare typically formed from a metal. Each of packing stack20band packing stack20atypically include one male gland, such as gland34a, and one female gland, such as gland34b, to complement the cross-sections of packings36a,36b. Packings36a,36bare sandwiched between glands34a,34b.

Packings36a,36bare arrayed in a coaxial stack about longitudinal axis A-A prior to installation. Glands34a,34bare disposed on opposite sides of packings36a,36b. Top portion48extends around top side41of clip40. Top portion48can also be referred to as a bracket. Bottom portion50extends around bottom side43of clip40. Bottom portion50can also be referred to as a bracket. As shown, top portion48extends from a first axial end of spine52and bottom portion50extends from a second axial end of spine52. In some examples, spine52is the only portion of clip40that extends between and connects top portion48and bottom portion50. Each of top portion48and bottom portion50can be arcuate, though it is understood that each of top portion48and bottom portion50can be of any desired configuration for receiving and retaining packing stack20. Upper arms56a,56bextend from opposite lateral sides of spine52. Lower arms58a,58bsimilarly extend from opposite lateral sides of spine52. Side opening54is defined between upper arm56aand upper arm56b, and between lower arm58aand lower arm58b.

InFIG. 2A, packings36a,36band glands34a,34bare shown in an exploded configuration, such that packings36a,36bare not in contact in a coaxially aligned stack. Prior to installation on clip40, packings36a,36band glands34a,34bare placed in the arrangement shown inFIG. 2B, such that packings36a,36band glands34a,34bare in contact and in coaxial alignment for installation on piston12(FIGS. 1 and 3A-3C).

From the arrangement shown inFIG. 2B, the assembled packing stack20formed by packings36a,36band glands34a,34bis installed on clip40to form the arrangement shown inFIG. 2C. Packing stack20is shifted laterally into clip40through side opening54. Upper arms56a,56band lower arms58a,58bare configured to elastically expand as packing stack20passes onto clip40through side opening54. Upper arms56a,56band lower arms58a,58bare further configured to elastically contract to retain packing stack20on clip40once inserted. Upper arms56a,56band lower arms58a,58bthereby retain packing stack20on clip40in the desired contacting and coaxial arrangement. Spine52can also flex in response to packing stack20passing through side opening54and into clip40.

Upper arms56a,56bengage first stack end42to prevent packing stack20from shifting laterally. As discussed in more detail below, upper arms56a,56bcan further prevent axial movement of packing stack20relative to clip40. Lower arms58a,58bengage second stack end44to prevent packing stack20from shifting laterally. As discussed in more detail below, lower arms58a,58bcan further prevent axial movement of packing stack20relative to clip40. Clip40prevents packings36a,36band glands34a,34bfrom separating prior to and during installation, thereby maintaining packings36a,36band glands34a,34bin the desired co-axial stack for proper alignment during placement on piston12. Central bore46is exposed on both the top and bottom sides of clip40to allow for insertion of piston12into packing stack20through central bore46of packing stack20. As such, a first end opening extends axially through top portion48such that central bore46is exposed through the first end opening, and a second end opening extends axially through bottom portion50such that central bore46is exposed through the second end opening.

FIGS. 3A-3Cillustrate the installation of packing stack20on piston12Assembly38is aligned with piston rod22such that second end28of piston rod22is coaxially aligned with central bore46through packing stack20. With piston rod22and central bore46coaxially aligned, assembly38is moved in direction A (e.g., axially) from the position shown inFIG. 3Ato the position shown inFIG. 3Bsuch that second end28is received within central bore46. Gland34acan contact shoulder60with packing stack20fully inserted onto piston rod22. Shoulder60can thereby provide a visual indication to the user that packing stack20is properly positioned, and can provide a physical stop ensuring that packing stack20is properly positioned.

With assembly38disposed on piston rod22, piston head24(FIG. 1) can then be attached (e.g., by threading) to piston rod22to capture packing stack20on piston rod22. In some examples, clip40is configured such that a piston head24can be inserted between upper arms56a,56band into central bore46and then into the bore in second end28of piston rod22with clip40still disposed on packing stack20. As such, piston head24can connect to piston rod22with assembly38mounted on piston rod22, such that piston head24retains packing stack20on piston rod22during removal of clip40.

With packing stack20positioned on piston rod22, clip40can be pulled laterally relative to piston rod22to remove clip40from packing stack20, while leaving packing stack20on piston rod22. Clip40can be pulled off of packing stack20in direction B (e.g., sideways) such that packing stack20is pulled through side opening54. In some examples, direction B is orthogonal to lateral axis A-A. In this way, clip40is not slid off of packing stack20in an axial direction along lateral axis A-A (i.e. parallel with lateral axis A-A). Rather, removal of clip40from packing stack20causes top portion48and bottom portion50, and specifically upper arms56a,56band lower arms58a,58b, to elastically flex as upper arms56a,56band lower arms58a,58bfirst slide around and off of packing stack20and then completely disengage from packing stack20. Clip40thereby leaves packings36a,36band glands34a,34bcoaxially aligned and mounted on piston rod22(with or without piston head24attached to piston rod22). As such, clip40can be moved axially (e.g., up and down parallel with axis A-A of piston12) to place packing stack20on piston12, and then moved sideways (e.g., laterally, orthogonal to the axial direction) to remove clip40from over packing stack20while leaving packing stack20mounted on piston12.

Clip40can be formed from plastic (e.g., UHMWPE, polyethylene) or metal (e.g., aluminum). Packing stack20can be snapped into place in clip40and can be unsnapped upon removal of clip40from packing stack20. Elastic strain within the body of clip40, such as between upper arms56a,56band lower arms58a,58b, can pinch and hold the elements of packing stack20in place and in coaxial alignment within clip40.

Assembly38provides significant advantages. One benefit of clip40is that packings36a,36band glands34a,34bcan be placed and held in packing stack20in a proper order prior to installation. For example, packing stack20can be packaged in clip40(e.g., in a box, sack, blister pack, clamshell, or other package) with packings36a,36band glands34a,34bin the correct order at the factory. In some examples, packing stack20can be pre-oiled prior to assembly on clip40and packaging for shipment. The user, upon opening the package, does not need to order and assemble packings36a,36band glands34a,34b. Also, the user does not need to individually place the elements of packing stack20on the piston12. Instead, clip40facilitates installation by allowing the user to slide the fully assembled packing stack20onto piston12in a first direction (e.g, axially) and then remove clip40in a second direction (e.g., laterally) while maintaining packing stack20on piston12in the desired position and configuration.

FIG. 4Ais an isometric view of clip40.FIG. 4Bis a bottom plan view of clip40.FIG. 4Cis a top plan view of clip40.FIG. 4Dis a side elevation view of clip40.FIG. 4Eis a rear elevation view of clip40.FIGS. 4A-4Ewill be discussed together. Relative up-down directions are indicated inFIG. 4A. Clip40includes top side41, bottom side43, top portion48, bottom portion50, spine52, side opening54, tabs62a-62e, and plates64a,64b. Top portion48includes upper arms56a,56b. Upper arms56a,56binclude guide surfaces66a,66b, respectively. Bottom portion50includes lower arms58a,58b. Lower arms58a,58binclude guide surfaces66c,66d, respectively. Is it noted that clip40is symmetric left-to-right, so a left view indicates what would be equivalent in a right view.

Top portion48and bottom portion50are disposed at opposite axial ends of spine52. Upper arms56a,56band lower arms58a,58bextend from spine23and wrap partially, but not completely, around (e.g., circumferentially) a packing stack, such as packing stack20(FIGS. 1-3C). Each of top portion48and bottom portion50can be arcuate. As such, each of upper arms56a,56band lower arms58a,58bcan also be arcuate.

Each upper arm56a,56bextends from spine52such that each upper arm56a,56bis independent of any other arm extending from spine52. As such, each upper arms56a,56bcan be cantilevered from spine52. Similarly, each lower arm58a,58bextends from spine52such that each lower arm58a,58bis independent of any other arm extending from spine52. As such, each lower arms58a,58bcan be cantilevered from spine52. As such, each of upper arms56a,56band each of lower arms58a,58bare free from the other arms and are not connected to the other arms, except by spine52. Each of upper arms56a,56band each of lower arms58a,58bindependently extends from spine52.

Guide surfaces66a-66dare flat surfaces that guide insertion of packings36a,36b(FIGS. 1-3C) and/or glands34a,34b(FIGS. 1-3C) into clip40. As shown, guide surfaces66a,66bare formed by flat surfaces disposed at the distal ends68a,68bof curved upper arms56a,56b, and guide surfaces66c,66dare formed by flat surfaces disposed at the distal ends68c,68dof curved lower arms58a,58b. Side opening54extends between and is defined between guide surface66aand guide surface66band between guide surface66cand guide surface66d.

Tabs62a-62eextend radially inward towards axis A-A (FIGS. 3A-3C) from top side41of clip40and bottom side43of clip40. Tabs62a-62eprevent axial or up and down movement of the elements of packing stack20relative to the clip40. Tabs62a-62cextend radially inward from the bottom side of clip40. Tabs62a,62bextend from lower arms58a,58b, respectively. Tab62cextends from spine52. Tabs62d,62eextend from upper arms56a,56b, respectively. While spine52is shown as including tab62con bottom side43, it is understood that spine52can include a tab62on top side41or tabs62on both top side41and bottom side43. While lower arms58a,58band upper arms56a,56bare each shown as including a single tab62, it is understood that each of lower arms58a,58band upper arms56a,56bcan include more than one tab62. In some examples, some of lower arms58a,58band upper arms56a,56binclude no tabs62while others include one or more tabs62. Tabs62a-62eprevent axial movement of packing stack20relative to clip40. Upper arms56a,56band lower arms58a,58bprevent undesired sideways or lateral movement of the elements of packing stack20relative to clip40.

Plates64a,64bare disposed at distal ends68a,68bof upper arms56a,56b, respectively. Plates64a,64bextend radially inward from upper arms56a,56b. Plates64a,64bcan function as tabs, similar to tabs62a-62e, preventing axial (up and down) movement of the elements of packing stack20relative to clip40. Plates64a,64balso guide insertion of packings36a,36band/or glands34a,34binto clip40.

Side opening54provides a passageway through which the elements of packing stack20can be inserted into clip40to be securely captured within clip40. In some examples, side opening54is the only opening or space through which the elements of packing stack20can be inserted and/or removed from clip40. In some cases, side opening54is the only opening or space through which the whole assembled packing stack20can be inserted and/or removed from clip40. In some cases, side opening54is the only opening or space through which the individual packings36a,36band/or glands34a,34bof packing stack20can be inserted and/or removed from clip40.

Side opening54has width W, shown inFIG. 4C, which widens and narrows on insertion and withdrawal of the elements of packing stack20through side opening54. Upper arms56a,56band lower arms58a,58bare configured to elastically flex as packing stack20passes into and out of clip40. Width W of side opening54elastically widens during insertion of the elements of packing stack20into the center of clip40. Width W of side opening54elastically narrows after the elements of packing stack20pass through side opening54and the elements are contained within clip40(e.g., coaxial with axis A-A). Such elastic narrowing due to spring force helps retain packing stack20within clip40. Width W of side opening54elastically widens during passage of the elements of packing stack20through side opening54during removal of packing stack20from clip40. Width W of side opening54elastically narrows after passage of the elements of packing stack20through side opening54during removal of packing stack20from clip40.

Tabs62d,62eand plates64a,64bengage the first stack end42(FIGS. 2A-2C) and tabs62a-62cengage second stack end44(FIGS. 2A-2C) of packing stack20to prevent the elements of packing stack20from disengaging from clip40in either the up or down axial directions. Specifically, tabs62d,62eand plates64a,64bare peripherally arrayed around a top side of clip40and extend radially inward toward axis AA. Tabs62d,62eand plates64a,64bengage the top peripheral surface of packing stack20to contain packing stack20within clip40. Likewise, tabs62a-62care peripherally arrayed around a bottom side of clip40and extend radially inward toward axis AA. Tabs62a-62cengage the bottom peripheral surface of packing stack20to contain packing stack within clip40.

Tabs62d,62eand plates64a,64bon top portion48have a greater length than tabs62a-62con bottom portion50, such that tabs62d,62eand plates64a,64bextend further toward axis A-A at the center of clip40than tabs62a-62c. When packing stack20is contained within clip40and axially aligned with axis A-A, tabs62a-62cdo not overlap, cover, and/or block the bottom opening of central bore46(best seen inFIGS. 2B-3A) through packing stack20. As such, central bore46of packing stack20is fully exposed through bottom portion50of clip40to allow insertion of piston rod22(best seen inFIGS. 3A-3C) into central bore46of packing stack20from bottom portion50of clip40, thereby facilitating mounting of packing stack20on piston12(FIG. 1). With packing stack20mounted within clip40and axially aligned with axis A-A, tabs62d,62eand/or plates64a,64bpartially cover and block the top opening of central bore46in packing stack20. Tabs62d,62eand/or plates64a,64bpartially cover and block the top opening in central bore46to prevent insertion of piston12through the top opening of central bore46of packing stack20. As such, each of tabs62d,62eand plates64a,64bcan also be referred to at a block that extends over and covers at least part of central bore46. While top portion48includes one or more blocks, bottom portion50does not include a projection extending over and covering at least part of central bore46, such that central bore46can be fully exposed through the opening through bottom portion50.

Packing stack20can be directionally oriented, with packings36a,36band/or glands34a,34bhaving up and down orientations, such that packing stack20does not provide the desired sealing when installed in the incorrect, upside-down orientation. Clip40blocking one of the top or bottom openings of central bore46, while exposing the other of the top or bottom openings, helps prevent packing stack20from being mounted on piston12in the incorrect orientation. For example, if the user attempts to install packing stack20from the incorrect orientation, tabs62d,62eand plates64a,64binterfere with and prevent piston12from entering into central bore46of packing stack20.

Clip40provides significant advantages. Tabs62a-62eand plates64a,64bretain packing stack20on clip and prevent packing stack20from moving axially relative to clip40. In addition, upper arms56a,56band lower arms58a,58bextend around packing stack20and retain packing stack20on clip40. Upper arms56a,56band lower arms58a,58bare configured to elastically deform to allow packing stack20to slide in and out of side opening54while installing packing stack20in clip40or on piston rod22, while otherwise retaining packing stack20within clip40. As such, assembly38is a standalone component that coaxially aligns the elements of packing stack20in the desired order for installation and maintains the elements in that desired order until installation. Clip40holds the elements of packing stack20in order and alignment prior to installation. Clip40further facilities installation by sliding packing stack20onto piston12and pulling away from packing stack20while maintaining packing stack20on piston12. No additional tools besides assembly38are required to install packing stack20on piston12.