US3391646A - Piston assembly for pump - Google Patents

Piston assembly for pump Download PDF

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Publication number
US3391646A
US3391646A US671368A US67136867A US3391646A US 3391646 A US3391646 A US 3391646A US 671368 A US671368 A US 671368A US 67136867 A US67136867 A US 67136867A US 3391646 A US3391646 A US 3391646A
Authority
US
United States
Prior art keywords
seal
piston
annular
piston assembly
plug
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US671368A
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English (en)
Inventor
Paul W Schlosser
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US671368A priority Critical patent/US3391646A/en
Priority to GB1233091D priority patent/GB1233091A/en
Priority to FR1561829D priority patent/FR1561829A/fr
Priority to SE06202/68A priority patent/SE340753B/xx
Priority to JP43030360A priority patent/JPS4937925B1/ja
Priority to CH736168A priority patent/CH494910A/de
Application granted granted Critical
Publication of US3391646A publication Critical patent/US3391646A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/16—Casings; Cylinders; Cylinder liners or heads; Fluid connections
    • F04B53/162—Adaptations of cylinders
    • F04B53/164—Stoffing boxes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/10—Valves; Arrangement of valves
    • F04B53/12—Valves; Arrangement of valves arranged in or on pistons
    • F04B53/121—Valves; Arrangement of valves arranged in or on pistons the valve being an annular ring surrounding the piston, e.g. an O-ring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/14—Pistons, piston-rods or piston-rod connections
    • F04B53/143—Sealing provided on the piston
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/164—Sealings between relatively-moving surfaces the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid

Definitions

  • a piston reciprocating in the cylinder of a piston pump, has an annular seal around its periphery with a fiuid venting passage communicating opposite sides of the seal to equalize pressure on opposite sides of the seal during a suction stroke of the piston.
  • Disc'shaped sealing means are located behind the seal for closing the venting passage during the pressure stroke of the piston.
  • the present invention relates generally to piston pumps, and more particularly to a piston assembly thereof having structure which prevents leakage of liquid from the front side to the back side of the piston during cyclic operation of the piston.
  • a piston pump includes a cylinder having an inner open end communicating with a pump compartment and an outer end which is sealed from the atmosphere.
  • a piston reciprocates within the cylinder, in a cycle including pressure and suction strokes.
  • the piston includes a cylindrical plug around the periphery of which is located an annular seal composed of elastic material such as rubber.
  • the present invention provides a fluid venting passage communicating opposite sides of the annular seal, to equalize the pressure on the inner and outer sides of the piston, during the suction stroke of the piston, to thereby prevent elastic deformation and distortion of the elastic annular seal during the suction stroke. This, in turn, eliminates the likelihood of any liquid from the pump compartment working its way around the outer periphery of the seal during the pressure stroke of the piston. Means are also provided to seal the venting means during the pressure stroke.
  • FIGURE 1 is a side elevational view, partially in section and partially cut away, illustrating an embodiment of a piston assembly constructed in accordance with the present invention, with the piston assembly moving in a pressure stroke;
  • FIGURE 2 is a view similar to FIGURE 1 with the piston assembly moving in a suction stroke;
  • FIGURE 3 is an exploded perspective view of the embodiment of FIGURES l2;
  • FIGURE 4 is a view similar to FIGURE 1 showing another embodiment of a piston assembly constructed in accordance with the present invention and with the piston assembly moving in a pressure stroke;
  • FIGURE 5 is a view similar to FIGURE 4, showing the piston assembly of FIGURE 4 in a suction stroke;
  • FIGURE 6 is an exploded perspective view of the piston assembly of FIGURES 45;
  • FIGURE 7 is a view similar to FIGURE 1, showing a further embodiment, with the piston assembly moving in a suction stroke;
  • FIGURE 8 is a View similar to FIGURE 7, with the piston assembly moving in a pressure stroke;
  • FIGURE 9 is an exploded perspective view of the piston assembly of FIGURES 7-8.
  • FIGURE 10 is a fragmentary view, similar to FIGURE 7, illustrating a modification of the embodiment of FIG- URES 710.
  • FIGURES l and 2 there is shown a pump indicated generally at Ill and comprising a compartment 11 into which liquid being pumped is received through an inlet line 12 and out of which the liquid is expelled through an outlet line 13.
  • Communicating with compartment 11 is the inner open end 17 of a cylinder 16 having an outer end 18 closed by a boot seal 19 having an outer rim 23 secured to the outside of cylinder 16 and an inner rim 21 secured around the inner end of a piston rod 22.
  • a piston assembly illustrated in exploded perspective in FIGURE 3, is attached to piston rod 22 by a bolt having a head 31.
  • a bolt having a head 31.
  • a disc shaped piston front plate 32 mounted on bolt 3! are a disc shaped piston front plate 32, a cylindrical plug 33 and a pair of back-up washers 34, 35.
  • a cup seal indicated generally at 49 and an annular disc 46 composed of springable material. Disc as is normally urged to the sprung condition illustrated in FIGURES 2 and 3.
  • Cup seal is composed of elastic material, such as rubber; and it has an inner circular flange 41, a web 42 and an outer circular flange 43 which normally wipes the inner surface of cylinder 16. Extending through the web 42 of cup seal 49 are vent holes or fluid-passage means 45, communicating the front or inner side of cup seal 49 with the back or outer side of cup seal 40.
  • FIGURE 2 illustrates a suction stroke of the piston assembly.
  • the fluid pressure on the inner side of the piston assembly (to the left in FIGURE 2) would be less than the pressure on the outer side (to the right in FIGURE 2).
  • holes 45 permits air to pass through holes 45 from the outer side to the inner side of cup seal 49 during the suction stroke of the piston assembly thus equalizing the pressure on both sides of the cup seal and preventing distortion and deformation of the cup seal, as would occur in the absence of holes 45.
  • Annular disc 46 slidably mounted on plug 33, is provided to seal holes 45 during a pressure stroke (FIG- URE 1) of the piston assembly, the annular disc being compressed or sandwiched between cup seal 40 and backup washer 34. The cup seal is forced back against annular disc 46 during a pressure stroke.
  • annular disc 46 During a suction stroke of the piston assembly, thspringable nature of annular disc 46 causes it to return to the normally sprung condition, shown in FIGURE 2, in which condition the annular disc does not close holes 45. In other words, the springable nature of disc 46 pushes cup seal 40 and holes 45 away from the disc during a suction stroke of the piston assembly.
  • annular disc 46 be composed of springable material normally urging the disc to the sprung condition, illustrated in FIGURE 2., during the suction stroke of the iston. If disc 46 was flat or unsprung during a suction stroke of the piston assembly, the disc would be sucked against holes 4-5, thus closing them and preventing the passage of air from the back or outer side of the piston assembly to the front or inner side thereof.
  • Annular disc 46 has an inner circular edge 4-3, having a diameter greater than the outside diameter of cylindrical plug 33. Accordingly, inner circular edge 48 and the outside surface of plug 33 define an annular space therebetween.
  • cup seal 40 During the pressure stroke of the piston assembly (FIGURE 1), the pressure exerted against cup seal 40 is sufficient to urge it to extrude into whatever space is available behind it. In the absence of the annular space, defined by inner circular edge 48 of annular disc 46 and the outside surface of plug 33, the cup seal would extrude into the space between the inner surface of cylinder 16 and the outer circumferential surface of back-up Washers 34, 35. By providing an annular space between disc 46 and plug 33, such extrusion, as has a tendency to occur, would 'be into this annular space, rather than between cylinder 16 and the back-up washers 34, 35. Extrusion of the latter type is undesirable because it causes excess wear on the cup seal, a defect not occurring when the cup seal is caused to extrude into the annular space between disc 46 and plug 33.
  • FIGURES 4-6 differs from the embodiment of FIGURES 1-3 in that the annular disc 46 is eliminated and the cup seal, indicated generally at 149, has larger dimensions to increase the resistance thereof to extrusion on a pressure stroke of the piston.
  • cup seal has dimensions of sufficient magnitude to resist extrusion, during the pressure stroke of the piston, into the space between cylinder 16 and back-up washers 34, 35.
  • annular seal 2% there are no holes through the annular seal 2% except for the central opening therethrough; and the inner diameter of seal 240 is sufiiciently larger than the outside diameter of the cylindrical plug 233 to loosely mount the seal on the plug and to define therebetween an annular space 245 communicating with an opening 246 in front plate 232 engaging the front end of plug 233. Opening 246 and annular space 245 define the fluid-passage for the embodiment of FIGURES 79.
  • Cylindrical plug 233 is slightly thicker in an axial direction than is annular seal 240.
  • seal 249 could be about one-eighth inch thick, and plug 233 could be 0.015 inch thicker.
  • the loose fit of seal 240 on plug 233 mounts the seal for reciprocal movement axially along plug 233 between a rearward position (FIG. 8) on a pressure stroke and a forward position (FIG. 7) on a suction stroke.
  • annular seal 340 is disc-shaped rather than cup-shaped as in FIG- URES 79.
  • the seal 340 has the same outside diameter at any axial location on the seal.
  • the elastic seals both of FIGURES 7-9 and of FIG- URE 10, have dimensions of sufiicient magnitude to resist extrusion rearwardly between the outer periphery of back-up washer 34 and the inner surface of cylinder 16, during a pressure stroke.
  • hollow cylinder means with an inner open end and an outer end behind said inner open end;
  • piston means mounted for reciprocal movement within the cylinder means in a cycle including suction and pressure strokes;
  • said piston means comprising a cylindrical plug having an outer diameter less than the inner diameter of the cylinder means
  • said piston means including annular seal mounted on said plug and having an outer periphery for wiping the interior of said cylinder means;
  • said piston means including a rigid backing member mounted behind said plug to restrict rearward movement of the annular seal on the plug during a pressure stroke of the piston means;
  • the additional feature comprising fluid-passage means communicating opposite sides of said annular seal for equalizing the pressure on said opposite sides of the annular seal during a suction stroke of the piston means so as to prevent the outer periphery of the annular seal from distorting inwardly during said suction stroke;
  • said fluid-passage means comprising means extending through said seal.
  • said annular seal is a cup seal having an inner circular flage mounted on said plug, an outer circular flange for wiping the interior of said cylinder means, and a web between said flanges; and said fluid-passage means comprises holes extending through the web of the cup seal.
  • said fluid-passage closure means comprises means for closing said holes in the web of the cup seal in response to a pressure stroke of the piston means and for maintaining the holes in an open condition during a suction stroke of the piston means. 5.
  • said fluidpassage closure means comprises:
  • annular disc mounted around said plug, between the cup seal and said rigid backing member, and in facing relation with the holes in the web of the cup seal; said disc being composed of springable material normally urging said disc away from said holes during a suction stroke of the piston means.
  • said cylindrical plug includes means engaging said rigid backing member for restricting inward movement of the rigid backing member toward the annular seal, during a suction stroke of the piston means, to prevent the rigid backing member from sealing said fluidpassage during said suction stroke.
  • said annular seal is a cup seal having an inner circular flange mounted on said plug, an outer circular flange for wiping the interior of said cylinder means, and a web between said flanges;
  • cup seal is composed of material, and has dimensions of suflicient magnitude, to impart, to the cup seals outer flange, resistance to extrusion rearwardly between the cylinder means and the rigid backing member during a pressure stroke of the piston means.
  • said piston means includes a rigid front plate located adjacent the front surface of said annular seal;
  • said annular seal has an inner diameter greater than the outer diameter of said cylindrical plug and said plug is thicker, in an axial direction, than said annular seal at the inner periphery thereof, whereby said annular seal is mounted for reciprocal movement axially along said plug between said front plate and said rigid backing member in response to pressure and suction strokes of said piston means;
  • the inner periphery of the annular seal and the outer surface of the cylindrical plug define an annular space therebetween;
  • said annular seal is disc-shaped and has the same outside diameter at any axial location on the annular seal.
  • said annular space constitutes the only fluid-passage through said elastic seal.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Details Of Reciprocating Pumps (AREA)
  • Reciprocating Pumps (AREA)
  • Sealing Devices (AREA)
US671368A 1967-09-28 1967-09-28 Piston assembly for pump Expired - Lifetime US3391646A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US671368A US3391646A (en) 1967-09-28 1967-09-28 Piston assembly for pump
GB1233091D GB1233091A (de) 1967-09-28 1968-05-06
FR1561829D FR1561829A (de) 1967-09-28 1968-05-08
SE06202/68A SE340753B (de) 1967-09-28 1968-05-08
JP43030360A JPS4937925B1 (de) 1967-09-28 1968-05-08
CH736168A CH494910A (de) 1967-09-28 1968-05-17 Pumpenkolben einer Kolben-Zylinder-Anordnung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US671368A US3391646A (en) 1967-09-28 1967-09-28 Piston assembly for pump

Publications (1)

Publication Number Publication Date
US3391646A true US3391646A (en) 1968-07-09

Family

ID=24694245

Family Applications (1)

Application Number Title Priority Date Filing Date
US671368A Expired - Lifetime US3391646A (en) 1967-09-28 1967-09-28 Piston assembly for pump

Country Status (6)

Country Link
US (1) US3391646A (de)
JP (1) JPS4937925B1 (de)
CH (1) CH494910A (de)
FR (1) FR1561829A (de)
GB (1) GB1233091A (de)
SE (1) SE340753B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3620652A (en) * 1968-12-13 1971-11-16 Philips Corp Compressor with rolling diaphragm seal
US3981146A (en) * 1972-09-13 1976-09-21 Borg-Warner Corporation Variable ratio master cylinder
US4002079A (en) * 1975-08-27 1977-01-11 Hall William A Breathing protector boot for impactor tools
US4208060A (en) * 1979-01-15 1980-06-17 Bellofram Corporation Sealed shaft
US4222310A (en) * 1978-12-04 1980-09-16 Eaton Corporation Brake actuator fastener assembly
US4251049A (en) * 1979-01-22 1981-02-17 Muehl Herman D Tank valve apparatus
US4253675A (en) * 1979-11-01 1981-03-03 Bellofram Corporation Improvements of sealed shafts
US4579041A (en) * 1983-05-04 1986-04-01 Interlego A.G. Fluid-pressure operable devices and sealing means therefor
US10508740B2 (en) * 2010-01-28 2019-12-17 Trelleborg Sealing Solutions Germany Gmbh Rotary sealing arrangement

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2454544A1 (fr) * 1979-04-19 1980-11-14 Bronzavia Sa Pompe a barillet, notamment pour fluide agressif
GB2074665B (en) * 1979-11-19 1983-11-09 Bionostics Sa Double acting continuous flow system type pump

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2322010A (en) * 1940-03-07 1943-06-15 Hydraulic Brake Co Piston
US3101131A (en) * 1960-11-07 1963-08-20 Bourcier Carbon Previnquieres Hydraulic pneumatic shock absorber

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2322010A (en) * 1940-03-07 1943-06-15 Hydraulic Brake Co Piston
US3101131A (en) * 1960-11-07 1963-08-20 Bourcier Carbon Previnquieres Hydraulic pneumatic shock absorber

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3620652A (en) * 1968-12-13 1971-11-16 Philips Corp Compressor with rolling diaphragm seal
US3981146A (en) * 1972-09-13 1976-09-21 Borg-Warner Corporation Variable ratio master cylinder
US4002079A (en) * 1975-08-27 1977-01-11 Hall William A Breathing protector boot for impactor tools
US4222310A (en) * 1978-12-04 1980-09-16 Eaton Corporation Brake actuator fastener assembly
US4208060A (en) * 1979-01-15 1980-06-17 Bellofram Corporation Sealed shaft
US4251049A (en) * 1979-01-22 1981-02-17 Muehl Herman D Tank valve apparatus
US4253675A (en) * 1979-11-01 1981-03-03 Bellofram Corporation Improvements of sealed shafts
US4579041A (en) * 1983-05-04 1986-04-01 Interlego A.G. Fluid-pressure operable devices and sealing means therefor
US10508740B2 (en) * 2010-01-28 2019-12-17 Trelleborg Sealing Solutions Germany Gmbh Rotary sealing arrangement

Also Published As

Publication number Publication date
JPS4937925B1 (de) 1974-10-14
FR1561829A (de) 1969-03-28
CH494910A (de) 1970-08-15
SE340753B (de) 1971-11-29
GB1233091A (de) 1971-05-26

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