US20070253849A1 - Pump with variable stroke piston - Google Patents

Pump with variable stroke piston Download PDF

Info

Publication number
US20070253849A1
US20070253849A1 US11/412,510 US41251006A US2007253849A1 US 20070253849 A1 US20070253849 A1 US 20070253849A1 US 41251006 A US41251006 A US 41251006A US 2007253849 A1 US2007253849 A1 US 2007253849A1
Authority
US
United States
Prior art keywords
piston
spring
chamber
driver
liquid
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.)
Abandoned
Application number
US11/412,510
Other languages
English (en)
Inventor
Brian Holt
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.)
Campbell Hausfeld LLC
Original Assignee
Campbell Hausfeld Scott Fetzer Co
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 Campbell Hausfeld Scott Fetzer Co filed Critical Campbell Hausfeld Scott Fetzer Co
Priority to US11/412,510 priority Critical patent/US20070253849A1/en
Assigned to CAMPBELL HAUSFELD/SCOTT FETZER COMPANY reassignment CAMPBELL HAUSFELD/SCOTT FETZER COMPANY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HOLT, BRIAN D.
Priority to CA002558203A priority patent/CA2558203A1/en
Priority to TW095132809A priority patent/TW200741102A/zh
Priority to CNA2006101409567A priority patent/CN101165344A/zh
Priority to MXPA06013342A priority patent/MXPA06013342A/es
Publication of US20070253849A1 publication Critical patent/US20070253849A1/en
Abandoned legal-status Critical Current

Links

Images

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
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/12—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by varying the length of stroke of the working members
    • F04B49/121—Lost-motion device in the driving mechanism

Definitions

  • This application relates to liquid pumps.
  • a liquid pump includes a piston that reciprocates in a cylindrical chamber.
  • the piston draws liquid through an inlet valve into the chamber during an intake stroke and forces the liquid out of the chamber through an outlet valve during a delivery stroke.
  • a pump apparatus includes a housing located on an axis.
  • the housing has a chamber, an inlet valve and an outlet valve.
  • a piston driver is configured to axially reciprocate.
  • a piston is a piston configured to reciprocate in the chamber to draw liquid into the chamber through the inlet valve during an intake stroke and to discharge the liquid out of the chamber through the outlet valve during a delivery stroke.
  • a spring axially biases the piston to a base position relative to the driver, so that the driver, when reciprocating, will drive the piston to reciprocate.
  • a preload structure preloads the spring to enable pressure of the liquid in the chamber to displace the piston away from the base position against the spring bias after the pressure exceeds a threshold level.
  • the spring has a spring constant that increases with increasing compression of the spring.
  • the spring is configured to render the volume of liquid delivered during each delivery stroke inversely related to output pressure of the pump.
  • the preload is manually adjustable.
  • the preload structure includes a protrusion on the piston within the driver, and further includes a stop surface in the driver that blocks the protrusion from exiting the driver and against which the protrusion is biased by the spring.
  • the spring is configured to absorb the entire reciprocation of the driver in a situation where liquid is blocked from exiting the outlet valve piston while the driver continues to reciprocate.
  • FIG. 1 is a schematic view of a pressure washer that includes a pump
  • FIGS. 2-4 are schematic sectional views of the pump at different stages during its operation.
  • FIG. 5 is a schematic view of a spring of the pump.
  • the apparatus 1 shown in FIG. 1 has parts that are examples of the elements recited in the claims.
  • the apparatus thus includes examples of how a person of ordinary skill in the art can make and use the claimed invention. It is described here to meet the requirements of enablement and best mode without imposing limitations that are not recited in the claims.
  • the apparatus 1 is a pressure washer. It includes a pump 10 for pumping a liquid from a supply line 12 to an outlet line 14 .
  • the supply line 12 has an inlet hose 20 with a threaded end 22 configured to be screwed onto a water faucet.
  • the outlet line 14 has an outlet hose 24 connected to a spray nozzle 26 .
  • the pump 10 draws water from the inlet line 12 and forces it out the nozzle 26 in the form of a pressurized spray.
  • the pump 10 includes a housing 30 located on a central axis A.
  • the housing 30 has axially front and rear ends 32 and 34 and a cylindrical piston-bearing surface 36 defining a cylindrical chamber 38 .
  • the chamber 38 is centered on the axis A and extends forward from a rear opening 40 of the housing 30 .
  • Liquid enters the chamber 38 from the supply line 12 through an inlet check valve 42 .
  • the liquid exits the chamber 38 into the outlet line 14 through an outlet check valve 44 .
  • a piston 50 includes piston head 52 rigidly fixed to a piston rod 54 .
  • a threaded front end 56 of the rod 54 is screwed into a threaded bore 57 of the head 52 .
  • the length L of the piston 50 depends on the depth to which the rod 54 is screwed into the head 52 .
  • the head 52 extends from the rod 54 into the chamber 38 . It forms an annular liquid-tight seal with, and is axially slidable against, the piston-bearing surface 36 .
  • the head 52 and the housing 30 together enclose a compression cavity 58 , which is a closed section of the chamber 38 that has a volume that varies as the head 52 reciprocates.
  • a nut 60 is screwed onto the rear end 62 of the rod 54 and protrudes radially outward from the rod 54 .
  • the rear end 62 of the rod 54 is captured in a bore 70 of a piston driver 72 .
  • a threaded ring 74 surrounding the rod 54 is screwed into a threaded front end 76 of the bore 54 .
  • a rearward-facing stop surface 78 of the ring 74 blocks the nut 60 from exiting the bore 70 .
  • a bias spring 80 is wrapped about the rod 54 and compressed between respective spring bearing surfaces 82 and 84 of the head 52 and the driver 72 .
  • the spring 80 biases the rod 54 into a base position relative to the driver 72 , as shown in FIG. 2 , in which the nut 60 abuts the stop surface 78 .
  • the nut 60 and the stop surface 78 thus together preload the spring 80 .
  • the stop surface 78 is axially between the nut 60 and the bias spring 80 .
  • a return spring 90 is wrapped about the piston head 54 and compressed between respective spring bearing surfaces 92 and 94 of the housing 30 and the head 52 .
  • the return spring 90 keeps the driver 72 in contact with a front wobble surface 96 of a wobble plate 98 .
  • the plate 98 is attached to an axially-extending output shaft 100 of a motor 102 .
  • the wobble surface 96 is inclined with respect to the axis A so that it reciprocatingly pushes the driver 72 forward against the bias of the return spring 90 as the plate 98 rotates.
  • the piston 50 is driven by the driver 72 to reciprocate, with a series of intake and delivery strokes in phase with forward and rearward strokes of the driver 72 .
  • the delivery stroke starts with the piston 50 fully retracted as shown in FIG. 2 , and pressure P cav in the cavity 58 equaling supply line pressure P in plus crack pressure P crack of the inlet valve 42 . Thereafter during the delivery stroke, the piston 50 advances, causing the pressure in the cavity 58 to increase. At some point, as in FIG. 3 , when the cavity pressure P cav starts to exceed P out +P crack , the outlet valve 44 starts to open to let the liquid into the outlet line 14 . From then on, further advancement of the piston 50 delivers liquid into the outlet line 14 while P cav remains constant at P out +P crack . This continues until the piston 50 reaches a fully forward position shown in FIG. 4 , the outlet valve 44 closes, and cavity pressure P cav remains at P out + crack .
  • the intake stroke starts with the piston 50 fully extended as shown in FIG. 4 .
  • cavity pressure P cav gradually decreases.
  • P cav recedes below P in ⁇ P crack the inlet valve 42 opens to let liquid from the supply line 12 into the cavity 58 . Further retraction of the piston 50 draws liquid through the inlet valve 42 into the cavity 58 , while P cav remains constant at P in ⁇ P crack .
  • the intake stroke ends as shown in FIG. 2 with the piston 50 fully retracted.
  • the bias spring 80 functions as follows: At the start of the delivery stroke, portrayed in FIG. 2 , the cavity pressure P cav is too weak to overcome the preload of the bias spring 80 urging the nut 60 against the stop surface 78 . At some point during the delivery stroke, if and when the cavity pressure P cav increases sufficiently to overcome the preload, the nut 60 will start to separate from the stop surface 78 .
  • FIG. 4 shows the positions of the driver 72 and the piston 50 at the start of the delivery stroke in dashed lines and their positions at the end of the delivery stroke in solid lines. By the end of the delivery stroke, the displacement distance D p of the piston 50 is shorter than the displacement distance D D of the driver 72 by the separation distance AD of the nut 60 from the stop surface 78 .
  • ⁇ D is a smooth positive function of output pressure P out .
  • the function is “positive” in that ⁇ D increases with increasing P out throughout the pressure range, and “smooth” in that the second derivative of ⁇ D verses P out is finite over the operating range. Due to the density and incompressibility of the liquid filling the cavity 58 , ⁇ D is substantially unaffected by inertia of the piston head 52 .
  • the delivery stroke volume i.e., the volume of liquid delivered during each delivery stroke, is proportional to the displacement D P of the piston 50 , which equals displacement D D of the driver 72 minus ⁇ D. Therefore, when P out is above the threshold pressure, the delivery stroke volume is smoothly and inversely related to P out . When P out is below the threshold pressure, the delivery stroke volume is unaffected by varying P out .
  • the threshold can be manually increased by increasing the preload on the bias spring 80 . This can be done by screwing the rod 54 deeper into the head 52 or screwing the ring 74 deeper into the driver 72 . Either of these steps decreases the depth of the head 52 in the chamber 38 . The resulting increase in initial volume of the cavity 58 does not affect the achievable output pressure Pout, because the liquid is incompressible.
  • Power input by the pump 10 from the motor 102 is typically proportional to motor speed, delivery stroke volume and outlet pressure P out . Since the delivery stroke volume of this pump 10 decreases with increasing P out , the required power will tend to vary less with P out than without the reduction ⁇ D in stroke displacement.
  • the bias spring 80 is selected to yield a delivery stroke volume that is approximately inversely proportional to P out , i.e., proportional to 1/P out . That renders the input power approximately invariant with P out , so that a motor 102 optimized for one power level at one outlet pressure would be optimal for other pressures too.
  • This can be achieved by the bias spring 80 having a spring constant that increases with increasing spring compression.
  • a step-wise increasing spring constant can be achieved by the bias spring 80 comprising coil springs 111 and 112 differing in spring constant. In the example shown in FIG. 5 , the springs 111 and 112 are arranged in parallel, more specifically concentric, with successively shorter springs having successively higher spring constants.
  • a smoothly increasing spring constant can be achieved by the bias spring 80 comprising a single coil spring of smoothly varying wire thickness.
  • the spring constant and the preload for the bias spring 80 are preferably higher than for the return spring 90 . This ensures that most of the driver reciprocation will be passed to the piston 50 and absorbed by the return spring 90 and not absorbed by the bias spring 80 .
  • the bias spring's spring constant and preload are preferably sufficiently low, and its initial length sufficiently high, to enable the bias spring 80 to absorb the entire reciprocation stroke of the driver 72 in a situation where the piston 50 is jammed in its fully retracted position. Such a situation can occur if a clog in the outlet line 14 totally prevents the liquid from exiting the outlet valve 44 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Details Of Reciprocating Pumps (AREA)
  • Control Of Non-Positive-Displacement Pumps (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US11/412,510 2006-04-27 2006-04-27 Pump with variable stroke piston Abandoned US20070253849A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US11/412,510 US20070253849A1 (en) 2006-04-27 2006-04-27 Pump with variable stroke piston
CA002558203A CA2558203A1 (en) 2006-04-27 2006-08-30 Pump with variable stroke piston
TW095132809A TW200741102A (en) 2006-04-27 2006-09-06 Pump with variable stroke piston
CNA2006101409567A CN101165344A (zh) 2006-04-27 2006-10-16 带有可变冲程的活塞的泵
MXPA06013342A MXPA06013342A (es) 2006-04-27 2006-11-17 Bomba con piston de carrera variable.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/412,510 US20070253849A1 (en) 2006-04-27 2006-04-27 Pump with variable stroke piston

Publications (1)

Publication Number Publication Date
US20070253849A1 true US20070253849A1 (en) 2007-11-01

Family

ID=38621113

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/412,510 Abandoned US20070253849A1 (en) 2006-04-27 2006-04-27 Pump with variable stroke piston

Country Status (5)

Country Link
US (1) US20070253849A1 (zh)
CN (1) CN101165344A (zh)
CA (1) CA2558203A1 (zh)
MX (1) MXPA06013342A (zh)
TW (1) TW200741102A (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9978265B2 (en) 2016-04-11 2018-05-22 Tti (Macao Commercial Offshore) Limited Modular garage door opener
US10015898B2 (en) 2016-04-11 2018-07-03 Tti (Macao Commercial Offshore) Limited Modular garage door opener

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9388696B2 (en) 2010-05-19 2016-07-12 Graco Minnesota Inc. Removable shim clip for adjustable piston pump
CN103557134B (zh) * 2013-11-05 2016-07-13 杨庆祝 抽油井无能耗注液泵
CN107165798B (zh) * 2017-07-20 2020-08-07 东营市海天石油科技有限责任公司 油井加药泵
CN112523728B (zh) * 2021-02-09 2021-04-27 山东鼎点环保科技有限公司 一种套管气回收装置

Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US912502A (en) * 1907-12-21 1909-02-16 Charles E Squires Fluid-pressure-cushioning device.
US1154798A (en) * 1912-07-29 1915-09-28 Charles Otis Palmer Governor for air-compressors.
US2914240A (en) * 1955-04-07 1959-11-24 Bendix Westinghouse Automotive Air compressor
US3142318A (en) * 1962-12-18 1964-07-28 Mercier Jean Piston accumulator
US3168045A (en) * 1961-09-13 1965-02-02 Sebastiani Martin Pump for thick materials
US3314594A (en) * 1963-10-25 1967-04-18 Philips Corp Apparatus for compressing or expanding a medium, which apparatus includes a control device for regulating the amount of dead space
US3672402A (en) * 1970-09-14 1972-06-27 Eaton Yale & Towne Automatic precharge adjuster
US3965875A (en) * 1973-07-02 1976-06-29 Cummins Engine Company, Inc. Fuel injection system for diesel engines
US4551077A (en) * 1984-03-22 1985-11-05 Butterworth Inc. High pressure pump
US4621566A (en) * 1985-09-11 1986-11-11 Liquid Level Lectronics, Inc. Electric pump
US4765251A (en) * 1984-07-23 1988-08-23 Kaser Associates, Inc. Railway car truck with multiple effective spring rates
US4810231A (en) * 1985-08-08 1989-03-07 Fichtel & Sachs Ag Torsional vibration damper having springs with progressive characteristics
US4854541A (en) * 1988-08-08 1989-08-08 Iowa State University Research Foundation, Inc. Power line support
US4907622A (en) * 1987-07-10 1990-03-13 Spectrum Associates, Inc. Fluid reservoir device
US5244351A (en) * 1992-09-30 1993-09-14 Textron Inc. System for protecting a liquid pump
US6336626B1 (en) * 1999-07-19 2002-01-08 Moonraker Farm, Inc. Stirrup suspension
US6352018B1 (en) * 2000-04-20 2002-03-05 Spicer Technology, Inc. Hydraulic actuator assembly with integral damper/accumulator
US6595105B2 (en) * 2000-10-13 2003-07-22 Lg Electronics Inc. Reciprocating compressor

Patent Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US912502A (en) * 1907-12-21 1909-02-16 Charles E Squires Fluid-pressure-cushioning device.
US1154798A (en) * 1912-07-29 1915-09-28 Charles Otis Palmer Governor for air-compressors.
US2914240A (en) * 1955-04-07 1959-11-24 Bendix Westinghouse Automotive Air compressor
US3168045A (en) * 1961-09-13 1965-02-02 Sebastiani Martin Pump for thick materials
US3142318A (en) * 1962-12-18 1964-07-28 Mercier Jean Piston accumulator
US3314594A (en) * 1963-10-25 1967-04-18 Philips Corp Apparatus for compressing or expanding a medium, which apparatus includes a control device for regulating the amount of dead space
US3672402A (en) * 1970-09-14 1972-06-27 Eaton Yale & Towne Automatic precharge adjuster
US3965875A (en) * 1973-07-02 1976-06-29 Cummins Engine Company, Inc. Fuel injection system for diesel engines
US4551077A (en) * 1984-03-22 1985-11-05 Butterworth Inc. High pressure pump
US4765251A (en) * 1984-07-23 1988-08-23 Kaser Associates, Inc. Railway car truck with multiple effective spring rates
US4810231A (en) * 1985-08-08 1989-03-07 Fichtel & Sachs Ag Torsional vibration damper having springs with progressive characteristics
US4621566A (en) * 1985-09-11 1986-11-11 Liquid Level Lectronics, Inc. Electric pump
US4907622A (en) * 1987-07-10 1990-03-13 Spectrum Associates, Inc. Fluid reservoir device
US4854541A (en) * 1988-08-08 1989-08-08 Iowa State University Research Foundation, Inc. Power line support
US5244351A (en) * 1992-09-30 1993-09-14 Textron Inc. System for protecting a liquid pump
US6336626B1 (en) * 1999-07-19 2002-01-08 Moonraker Farm, Inc. Stirrup suspension
US6352018B1 (en) * 2000-04-20 2002-03-05 Spicer Technology, Inc. Hydraulic actuator assembly with integral damper/accumulator
US6595105B2 (en) * 2000-10-13 2003-07-22 Lg Electronics Inc. Reciprocating compressor

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9978265B2 (en) 2016-04-11 2018-05-22 Tti (Macao Commercial Offshore) Limited Modular garage door opener
US10015898B2 (en) 2016-04-11 2018-07-03 Tti (Macao Commercial Offshore) Limited Modular garage door opener
US10127806B2 (en) 2016-04-11 2018-11-13 Tti (Macao Commercial Offshore) Limited Methods and systems for controlling a garage door opener accessory
US10157538B2 (en) 2016-04-11 2018-12-18 Tti (Macao Commercial Offshore) Limited Modular garage door opener
US10237996B2 (en) 2016-04-11 2019-03-19 Tti (Macao Commercial Offshore) Limited Modular garage door opener

Also Published As

Publication number Publication date
MXPA06013342A (es) 2008-10-15
CN101165344A (zh) 2008-04-23
TW200741102A (en) 2007-11-01
CA2558203A1 (en) 2007-10-27

Similar Documents

Publication Publication Date Title
US20070253849A1 (en) Pump with variable stroke piston
US6206663B1 (en) Piston pump
US4365745A (en) Diaphragm pump
JP2017505405A (ja) 無脈動の容積式ポンプ及び無脈動の流体吐出方法
CN107762655B (zh) 大型二冲程压缩点火内燃机的气缸润滑设备
US3779669A (en) Pump spray unit
KR20190042670A (ko) 무맥동 펌프
DE502005010385D1 (de) Hochdruck-pumpenkolben-zylindereinheit
US7273036B2 (en) High-pressure fuel pump with a ball valve in the low-pressure inlet
US20070189911A1 (en) Liquid pump
US4500262A (en) Variable pressure and displacement reciprocating pump
JP5060587B2 (ja) エアレススプレーポンプ
AU2003273791A1 (en) A reciprocating liquid pump for delivery of liquid fuel to a domestic burner device
CN103470416A (zh) 一种应用于高压共轨燃油喷射系统的径向柱塞供油泵
CN218971319U (zh) 一种高压燃油泵及发动机
JP5984303B2 (ja) 燃料噴射補助装置及び燃料噴射補助装置を備える燃料噴射ポンプ
CN203452954U (zh) 一种应用于高压共轨燃油喷射系统的径向柱塞供油泵
TW201621165A (zh) 液體加壓幫浦出力軸潤滑結構
CN219101569U (zh) 液压泵
US20090104047A1 (en) Pump having multiple minimum flow mechanical stops
KR101575290B1 (ko) 펌프 이를 이용한 기체부스터
WO2017174405A1 (en) Fuel pump
JP2017180306A (ja) 燃料供給ポンプの構造
WO2014171410A1 (ja) 燃料噴射ポンプ
JP2009091955A (ja) サプライポンプ

Legal Events

Date Code Title Description
AS Assignment

Owner name: CAMPBELL HAUSFELD/SCOTT FETZER COMPANY, OHIO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HOLT, BRIAN D.;REEL/FRAME:017814/0106

Effective date: 20060426

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION