EP2430311A1 - Pump piston device - Google Patents

Pump piston device

Info

Publication number
EP2430311A1
EP2430311A1 EP10775146A EP10775146A EP2430311A1 EP 2430311 A1 EP2430311 A1 EP 2430311A1 EP 10775146 A EP10775146 A EP 10775146A EP 10775146 A EP10775146 A EP 10775146A EP 2430311 A1 EP2430311 A1 EP 2430311A1
Authority
EP
European Patent Office
Prior art keywords
piston
pump
seal
cylinder
compensation
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.)
Withdrawn
Application number
EP10775146A
Other languages
German (de)
French (fr)
Inventor
Per Olav Haughom
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.)
Siv ing Per Olav Haughom AS
Original Assignee
Siv ing Per Olav Haughom AS
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 Siv ing Per Olav Haughom AS filed Critical Siv ing Per Olav Haughom AS
Publication of EP2430311A1 publication Critical patent/EP2430311A1/en
Withdrawn legal-status Critical Current

Links

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
    • F04B53/14—Pistons, piston-rods or piston-rod connections
    • F04B53/148—Pistons, piston-rods or piston-rod connections the piston being provided with channels which are coacting with the cylinder and are used as a distribution member for another piston-cylinder unit
    • 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
    • F04B53/125—Reciprocating valves
    • 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
    • F16J15/40—Sealings between relatively-moving surfaces by means of fluid
    • 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
    • F16J15/56—Other sealings for reciprocating rods

Definitions

  • This invention relates to a pump piston. More particularly, it relates to a pump piston for reciprocating movement in a pump cylinder in which, between the pump piston and the pump cylinder, an annular space is formed which is defined by a first seal and a second seal, the annular space being pressurized.
  • seal wear may be a considerable problem, in particular in the case of high pressures.
  • WO document 2005/080836 discloses a pump in which the piston is provided with two seals with an intermediate annular space .
  • NO patent 321183 discloses a piston in which, on a portion of the external jacket surface of the piston facing the pressure side of the piston, an axially movable sleeve is formed, sealing against the piston. Externally, the piston and the sleeve are each provided with a respective seal sealing against the cylinder wall. The area between the external seals of the piston and the sleeve is pressurized by means of a fluid. During the pump stroke, the piston and the sleeve are moved towards the fluid which is to be pumped. The sleeve is thereby moved somewhat along the piston, so that pressure builds up between the two seals.
  • the sleeve is of such a design that the pressure is approximately the same on both sides of the seal surrounding the sleeve.
  • the movement of the sleeve on the piston and the relatively large cross-sectional area of the sleeve reduce the volumetric efficiency of the pump.
  • the invention has for its object to remedy or reduce at least one of the drawbacks of the prior art .
  • a pump piston is provided for reciprocating movement in a pump cylinder in which, between the pump piston and the pump cylinder, an annular space is formed, defined by a first seal and a second seal, the annular space being pressurized and the first seal and the second seal being in a common piece of material which constitutes the pump piston.
  • the pump piston is characterized by a compensation piston being movable in a compensation cylinder in the pump piston, the compensation piston communicating, by its first end portion, with the pressure side of the pump piston, and, at its second end portion, with the annular space via a piston channel.
  • the pump piston may be crank-operated or moved in other known ways, for example hydraulically or pneumatically.
  • a shoulder may prevent the compensation piston from being moved out of the compensation cylinder.
  • the annular space may be supplied with pressure fluid via a check valve and a cylinder channel.
  • the pressure fluid may thereby be supplied to the annular space at a considerably lower pressure than the operating pressure of the piston pump, as the check valve will close to the return flow of pressure fluid during the working stroke of the piston pump.
  • a pump piston in accordance with the invention exhibits the advantageous features from NO 321183 with respect to seal life, with just an insignificant reduction in the volumetric efficiency.
  • Figure 1 shows schematically a piston pump which is provided with a pump piston in accordance with the invention, the piston being moved in its suction stroke;
  • Figure 2 shows schematically the same as figure 1 but during the working stroke of the piston pump.
  • the reference numeral 1 indicates a piston pump comprising a pump casing 2 with a pump cylinder 4, a crankcase 6 and a valve block 8 for the medium which is to be pumped.
  • a driven crank 10 is supported in the crankcase 6 and connected, in a manner known per se, to a pump piston 12 by- means of a crank rod 14.
  • the pump piston 12 is reciprocatable in the pump cylinder 4.
  • the valve block 8 is formed with an inlet valve 16 and an outlet valve 18.
  • the pump piston 12 is provided with a first surrounding seal 20 which is relatively close to its pressure side 22, and a second surrounding seal 24 on the crank side of the first seal 20.
  • An annular space 26 is defined by the pump cylinder 4, the pump piston 12 and the seals 20, 24.
  • a compensation cylinder 28 has been bored into the pump piston 12 from the pressure side 22 of the pump piston 12.
  • a compensation piston 30 is sealingly and movably arranged in the compensation cylinder 28, a compensation piston chamber 32 being defined by the compensation cylinder 28 and the compensation piston 30.
  • the compensation piston chamber 32 communicates with the annular space 26 via a piston channel 34.
  • a shoulder 36 prevents the compensation piston 30 from being moved out of the compensation cylinder 28.
  • a supporting spring 38 may be arranged in the compensation piston chamber 32 and be arranged to move the compensation piston 30 in the direction towards the shoulder 36.
  • a feed pump 40 supplies the annular space 26 with pressure fluid via a pipe 42, a check valve 44 and a cylinder channel 46.
  • the pressure from the feed pump 40 is restricted by an overpressure valve 48.
  • the annular space 26 is filled with a preferably lubricating pressure fluid by the feed pump 40 via the pipe 42, the check valve 44 and the cylinder channel 46.
  • An appropriate maximum pressure which may be relatively low in relation to the maximum pressure of the piston pump 1, has been set on the overpressure valve 48.
  • Pressure fluid flows from the annular space 26 via the piston channel 34 into the compensation piston chamber 32, whereby the compensation piston 30 is moved until it hits the shoulder 36.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Details Of Reciprocating Pumps (AREA)

Abstract

A pump piston device (12) for reciprocating movement in a pump cylinder (4) in which, between the pump piston (12) and the pump cylinder (4), an annular space (26) is formed which is defined by a first seal (20) and a second seal (24), the annular space (26) being pressurized, and the first seal (20) and the second seal (24) being in a common piece of material which constitutes the pump piston (12).

Description

PUMP PISTON DEVICE
This invention relates to a pump piston. More particularly, it relates to a pump piston for reciprocating movement in a pump cylinder in which, between the pump piston and the pump cylinder, an annular space is formed which is defined by a first seal and a second seal, the annular space being pressurized.
In piston pumps working with particle-containing or non- lubricating fluids, seal wear may be a considerable problem, in particular in the case of high pressures.
According to the prior art, it is sought to relieve the problem by arranging scrapers or several successive seals, for example, around the piston.
WO document 2005/080836 discloses a pump in which the piston is provided with two seals with an intermediate annular space .
US patent 5701797 and EP patent application 1975409 deal with pumps in which there are two seals arranged in the cylinder pipe.
NO patent 321183 discloses a piston in which, on a portion of the external jacket surface of the piston facing the pressure side of the piston, an axially movable sleeve is formed, sealing against the piston. Externally, the piston and the sleeve are each provided with a respective seal sealing against the cylinder wall. The area between the external seals of the piston and the sleeve is pressurized by means of a fluid. During the pump stroke, the piston and the sleeve are moved towards the fluid which is to be pumped. The sleeve is thereby moved somewhat along the piston, so that pressure builds up between the two seals. The sleeve is of such a design that the pressure is approximately the same on both sides of the seal surrounding the sleeve. The movement of the sleeve on the piston and the relatively large cross-sectional area of the sleeve reduce the volumetric efficiency of the pump.
The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art .
The object is achieved according to the invention through the features which are specified in the description below and in the claims that follow.
A pump piston is provided for reciprocating movement in a pump cylinder in which, between the pump piston and the pump cylinder, an annular space is formed, defined by a first seal and a second seal, the annular space being pressurized and the first seal and the second seal being in a common piece of material which constitutes the pump piston. The pump piston is characterized by a compensation piston being movable in a compensation cylinder in the pump piston, the compensation piston communicating, by its first end portion, with the pressure side of the pump piston, and, at its second end portion, with the annular space via a piston channel.
Thus, it is possible to form the piston in a simple way, as the first seal and the second seal can be arranged in a common piece of material . The pump piston may be crank-operated or moved in other known ways, for example hydraulically or pneumatically.
A shoulder may prevent the compensation piston from being moved out of the compensation cylinder.
The annular space may be supplied with pressure fluid via a check valve and a cylinder channel. The pressure fluid may thereby be supplied to the annular space at a considerably lower pressure than the operating pressure of the piston pump, as the check valve will close to the return flow of pressure fluid during the working stroke of the piston pump.
The operation of the pump piston is described in the characterizing part of the application.
A pump piston in accordance with the invention exhibits the advantageous features from NO 321183 with respect to seal life, with just an insignificant reduction in the volumetric efficiency.
In what follows is described an example of a preferred embodiment which is visualized in the accompanying drawings, in which:
Figure 1 shows schematically a piston pump which is provided with a pump piston in accordance with the invention, the piston being moved in its suction stroke; and
Figure 2 shows schematically the same as figure 1 but during the working stroke of the piston pump.
In the drawings, the reference numeral 1 indicates a piston pump comprising a pump casing 2 with a pump cylinder 4, a crankcase 6 and a valve block 8 for the medium which is to be pumped. A driven crank 10 is supported in the crankcase 6 and connected, in a manner known per se, to a pump piston 12 by- means of a crank rod 14. The pump piston 12 is reciprocatable in the pump cylinder 4.
The valve block 8 is formed with an inlet valve 16 and an outlet valve 18.
The pump piston 12 is provided with a first surrounding seal 20 which is relatively close to its pressure side 22, and a second surrounding seal 24 on the crank side of the first seal 20.
An annular space 26 is defined by the pump cylinder 4, the pump piston 12 and the seals 20, 24.
A compensation cylinder 28 has been bored into the pump piston 12 from the pressure side 22 of the pump piston 12. A compensation piston 30 is sealingly and movably arranged in the compensation cylinder 28, a compensation piston chamber 32 being defined by the compensation cylinder 28 and the compensation piston 30. The compensation piston chamber 32 communicates with the annular space 26 via a piston channel 34.
A shoulder 36 prevents the compensation piston 30 from being moved out of the compensation cylinder 28. A supporting spring 38 may be arranged in the compensation piston chamber 32 and be arranged to move the compensation piston 30 in the direction towards the shoulder 36.
A feed pump 40 supplies the annular space 26 with pressure fluid via a pipe 42, a check valve 44 and a cylinder channel 46. The pressure from the feed pump 40 is restricted by an overpressure valve 48. During operation, the annular space 26 is filled with a preferably lubricating pressure fluid by the feed pump 40 via the pipe 42, the check valve 44 and the cylinder channel 46. An appropriate maximum pressure, which may be relatively low in relation to the maximum pressure of the piston pump 1, has been set on the overpressure valve 48.
Pressure fluid flows from the annular space 26 via the piston channel 34 into the compensation piston chamber 32, whereby the compensation piston 30 is moved until it hits the shoulder 36.
During the suction stroke of the piston pump 1, see figure 1, the pump piston 12 is moved in the direction towards the crank 10, the inlet valve 16 opens and pumped liquid enters the piston pump 1. The compensation piston 30 stays in its position, bearing against the shoulder 36, because of the pressure in the compensation piston chamber 32 and a possible underpressure in the piston pump 1.
When the piston pump 1 starts its pump stroke, see figure 2, the inlet valve 16 closes, whereby the pressure in the piston pump 1 increases until the outlet valve 18 opens. The increased pressure in the piston pump 1 works against the compensation piston 30 which is moved inwards in the compensation cylinder 28. The pressure in the compensation piston chamber 32 increases by the check valve 44 closing. The annular space 26 thereby gets the same pressure as the piston pump 1.
Thus, during the pressure stroke of the piston pump 1, there is approximately the same pressure on both sides of the first seal 20, which substantially reduces seal wear, even when pumping particle-laden liquid. The second seal 24, sealing against a clean lubricating fluid, receives full pumping pressure.

Claims

C l a i m s
1. A pump piston device (12) for reciprocating movement in a pump cylinder (4) in which there is formed, between the pump piston (12) and the pump cylinder (4) , an annular space (26) which is defined by a first seal (20) and a second seal (24) , the annular space (26) being pressurized, and the first seal (20) and the second seal (24) being in a common piece of material which constitutes the pump piston (12), c h a r a c t e r i z e d i n that a compensation piston (30) is movable in a compensation cylinder (28) in the pump piston (12), the compensation piston (30) communicating, by its first end portion, with the pressure side (22) of the pump piston (12), and, at its second end portion, with the annular space (26) via a piston channel (34) .
2. The device in accordance with claim 1, c h a r a c t e r i z e d i n that the annular space (26) is supplied with pressure fluid via a check valve (44) and a cylinder channel (46) .
EP10775146A 2009-05-13 2010-05-05 Pump piston device Withdrawn EP2430311A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO20091872A NO329833B1 (en) 2009-05-13 2009-05-13 Pump piston device
PCT/NO2010/000169 WO2010131976A1 (en) 2009-05-13 2010-05-05 Pump piston device

Publications (1)

Publication Number Publication Date
EP2430311A1 true EP2430311A1 (en) 2012-03-21

Family

ID=43085198

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10775146A Withdrawn EP2430311A1 (en) 2009-05-13 2010-05-05 Pump piston device

Country Status (7)

Country Link
US (1) US20120042773A1 (en)
EP (1) EP2430311A1 (en)
BR (1) BRPI1010928A2 (en)
CA (1) CA2756658A1 (en)
NO (1) NO329833B1 (en)
RU (1) RU2011146473A (en)
WO (1) WO2010131976A1 (en)

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1840045A (en) * 1930-05-30 1932-01-05 Frigidaire Corp Pump for refrigerating apparatus
US3146940A (en) * 1960-04-08 1964-09-01 Battelle Development Corp Reverse leakage seal for reciprocating parts
US3020885A (en) * 1961-09-01 1962-02-13 Weinstock Manuel Rotary servo valve controlled mechanism
DE2164590C3 (en) * 1971-12-24 1979-03-29 Alfred Teves Gmbh, 6000 Frankfurt Master cylinder for a dual-circuit brake system for vehicles, in particular motor vehicles
EP0304964B1 (en) * 1983-07-01 1991-08-07 Shibuya Kogyo Co., Ltd Apparatus for producing ultrahigh pressure water jet
US4598630A (en) * 1985-04-24 1986-07-08 University Of Ky Research Foundation Double acting self-flushing pump
US4906167A (en) * 1989-02-07 1990-03-06 Dresser Industries, Inc. Inherently flushing piston rod for a reciprocating pump
GB9307775D0 (en) * 1993-04-15 1993-06-02 Framo Dev Ltd Sealing system
NO321183B1 (en) * 2003-08-04 2006-04-03 Siv Ing Per Olav Haughom As Pump piston device
SE0400442D0 (en) * 2004-02-25 2004-02-25 Ingenjoers R A Teknik Fa Sealing arrangement for relatively movable parts and device including such a sealing arrangement
US7784395B2 (en) * 2007-03-28 2010-08-31 Clyde Union Inc. Zero emissions reciprocating pump

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2010131976A1 *

Also Published As

Publication number Publication date
US20120042773A1 (en) 2012-02-23
WO2010131976A1 (en) 2010-11-18
NO329833B1 (en) 2011-01-03
NO20091872L (en) 2010-11-15
BRPI1010928A2 (en) 2016-04-05
RU2011146473A (en) 2013-06-20
CA2756658A1 (en) 2010-11-18

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