EP0471145A1 - Etançon de mine hydraulique à régulation en longeur télescopique - Google Patents

Etançon de mine hydraulique à régulation en longeur télescopique Download PDF

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Publication number
EP0471145A1
EP0471145A1 EP91104019A EP91104019A EP0471145A1 EP 0471145 A1 EP0471145 A1 EP 0471145A1 EP 91104019 A EP91104019 A EP 91104019A EP 91104019 A EP91104019 A EP 91104019A EP 0471145 A1 EP0471145 A1 EP 0471145A1
Authority
EP
European Patent Office
Prior art keywords
valve
piston
stamp
bores
housing
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Withdrawn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
EP91104019A
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German (de)
English (en)
Inventor
Heinz-Jürgen Schlebusch
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.)
DAMS GmbH
Original Assignee
DAMS GmbH
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 DAMS GmbH filed Critical DAMS GmbH
Publication of EP0471145A1 publication Critical patent/EP0471145A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/50—Component parts or details of props
    • E21D15/51—Component parts or details of props specially adapted to hydraulic, pneumatic, or hydraulic-pneumatic props, e.g. arrangements of relief valves
    • E21D15/512—Arrangement of valves

Definitions

  • the invention relates to a telescopic pit stamp adjustable in length by hydraulic pressure, with at least one inner stamp tube and at least one outer stamp tube, the respective inner stamp tube being guided in a pressure-liquid-tight manner by a piston in the respective outer stamp tube, with a stamp head, a collar ring attached to the relevant outer stamp tube, a stamp foot, as well as a robbery and setting valve.
  • bottom valves which are installed in telescopic punches and have the task of controlling the upper stage and separating the higher pressure of the upper stage from the lower stage. They are designed as 2/2-way valves.
  • DE-PS 33 14 837 which goes back to the applicant, discloses a pressure relief valve, in particular for hydraulic systems used in mining, with an O-ring inserted in a longitudinal bore of a valve housing along an O-ring inserted in a circumferential annular groove and with one that can be moved up to a stop Valve piston, which is axially displaceable against the force of a valve spring or a spring system with a flat characteristic curve when a predetermined setpoint pressure is exceeded, the pressure fluid from an input side of the valve housing through an axial bore arranged in the valve piston and a plurality of radial bores lying in a radial plane and branching off from this bore can flow through to an outlet side of the valve housing and which can be pushed back into its closed position at the predetermined target setting pressure or below it under the action of the valve spring or the spring system, the stop from a circular ng-shaped, integrally connected to the valve piston flange, the outer diameter of which is larger than the diameter of the longitudinal bore of the valve housing and the axial
  • the size of the sliding fit between the valve piston and the cylinder wall of the valve housing longitudinal bore is h7 / H7 plus the corresponding standardized wear dimensions of the work gauges belonging to this fit.
  • the longitudinal bore for the valve piston is provided in the valve housing with an edge chamfer which widens the passage opening.
  • the wall thickness of the wall between the rear edge of the annular groove facing the outlet side of the valve housing and the outer surface of the valve housing in the region of the funnel-shaped edge chamfer is between 1.0 mm and 0.5 mm.
  • the valve piston has an outer diameter of 5 mm and eight radial bores with a diameter of 1.0 mm to 1.2 mm.
  • the O-ring has a Shore hardness of 100 Shore-A.
  • the valve housing is provided with four radial openings and an axial opening for the discharge of the pressure fluid and the edge chamfer of the passage opening for the valve piston in the valve housing is designed 0.5 mm x 90 °.
  • the invention has for its object to design a telescopic length-adjustable hydraulic pit ram according to the prerequisite type such that when the single ram is pressurized with hydraulic pressure, the piston head does not move against the collar.
  • This is to be achieved by means of a special stroke limiting valve which is to be spatially combined with the pressure relief valve in such a way that the structural dimensions of the stamp of this type are not enlarged to the outside and, in principle, an already known pressure relief valve can be used.
  • a combined stroke limiting and pressure relief valve is provided in the piston crown.
  • the stroke limiting valve is designed as a 2/3-way valve, the stroke limiting valve with the pressure relief valve being arranged in a common, cartridge-shaped housing.
  • the pressure relief valve from the same applicant known from DE-PS 33 14 837 can be used as the pressure relief valve, in which the stroke limiting valve can be arranged in a space-saving manner.
  • the stroke limiting valve relieves pressure on the hydraulic individual ram when the predeterminable extension length (setting length) of the ram tubes is reached, so that the piston crown can no longer move against the generally glued collar ring and damage it.
  • the stroke limiting valve is designed so that a shut-off body is tight at low pressures, for example at zero bar, when z. B. the inner punch tube is extended without load bearing.
  • the shut-off body of the stroke limiting valve is also easily controlled in the open position even when a predetermined position is reached, if the stamp chamber to be acted upon by the hydraulic pressure has high pressures of, for. B. 400 bar is applied. In these cases, too, the stroke limitation valve is tight and can still be easily controlled in the open position. In the invention, this is accomplished, among other things, with the aid of a differential piston.
  • the larger surface of the shut-off valve of the stroke limiting valve, acting in the closing direction, results in a reliable hydraulic closing of the stroke limiting valve.
  • a cylindrical spring ensures secure closing even at the lowest pressures of e.g. B. 0 bar if you neglect frictional forces.
  • the cross sections are designed so large that no pressure increase or force acts against the collar after mechanical opening.
  • the solution according to claim 2 results in a particularly advantageous construction.
  • the shut-off body of the stroke limiting valve is controlled in the open position via a valve control fork. Springs have the tendency to pull the telescopic tubes of the individual stamp into one another in order to shorten the stamp.
  • Claim 4 describes a preferred construction of the invention.
  • the telescopic, length-adjustable, hydraulically actuable pit stamp which can be seen in particular from FIGS. 1 and 2, has an outer stamp tube 1 and an inner stamp tube 2.
  • Reference number 5 denotes a lower guide band and reference number 6 denotes a lip ring seal, while 7 represents an O-ring.
  • a crown head 8 is fastened with a hexagon screw 9 and a self-locking nut 10.
  • a valve cartridge 12 is arranged orthogonally to the longitudinal axis 11 of the hydraulic pit ram, in which the pirate and set valve, not shown in detail, is arranged.
  • the reference numeral 13 designates a stamp head overall, while 14 designates a handle holder with a cap nut.
  • the associated handle is designated by reference number 15.
  • An upper guide band 16 is provided in the region of the handle holder 14, while 17 represents a dirt scraper.
  • the outer stamp tube 1 is provided with a stamp foot 18 which is connected to a stamp base 20 via countersunk screws 19.
  • a spring guide tube 21 is arranged coaxially to the longitudinal axis 11 of the hydraulic pit stamp, which is fastened at one end in the stamp head 13 at 22 by gluing. At its other end, the spring guide tube 21 is inserted into a correspondingly stepped bore of the piston 3, likewise by gluing at 23, and is firmly connected to the latter.
  • a spring holder 24 is arranged in the stamp head 13 and has an upper one designed as a tension spring Return spring 25 is mounted and also locked on the stamp head 13.
  • a lower return spring 26 is also arranged in the spring guide tube 21 coaxially with the upper return spring 25.
  • Upper and lower return springs 25 and 26 run coaxially to one another and coaxially to the spring guide tube 21 and thus also coaxially and in the axial direction of the longitudinal axis 11 of the hydraulic pit ram.
  • the lower return spring 26 is fastened to a lower spring holder 27, which is arranged in the stamping foot 18 via a hexagon nut 28.
  • Both the upper and the lower spring holder 24 or 27 each have an abutment plate 29 or 30 against which the upper return spring 25 with its end section facing the stamp head 13, on the one hand, or the lower return spring 26 with its end region facing the stamp foot 18 creates.
  • the reference numeral 31 designates a stroke limiting rod which passes completely through the lower return spring 26 and the upper return spring 25 partially centrally along the length.
  • the stroke limiting rod 31 has a control cam 32, which is designed as an annular collar and is integrally connected in terms of material to two control cam bushings 33 and 34, respectively.
  • the upper return spring 25 is supported with its lower end area against the collar-shaped control cam 32 and the lower return spring 26 with its upper end area against the control cam 32.
  • the upper and lower control cam bushings 33 and 34 also serve as spring holders for the upper and lower return springs 25 and 26.
  • control cam stop 35 is fixed by screws or the like.
  • the control cam stop 35 is designed in the form of an approximately cylindrical part and lies in the maximum extension length of the stamp parts 1 and 2 on the upper side of the upper control cam bushing 33 (FIG. 2).
  • the control cam 32 actuates a valve control fork 36 which can be pivoted about a pivot axis 37 which runs orthogonally to the longitudinal axis 11 (FIG. 2) and thereby displaces a valve control pin 38 which is arranged in a longitudinally displaceable manner in a valve control pin guide 39 .
  • the valve control pin 38 in turn displaces a control piston 40 (FIGS. 3 and 8) in the opening direction, so that a pressure chamber 41 of the pit ram to be acted upon with hydraulic fluid is relieved and the piston 3 does not abut against the collar 42.
  • the collar 42 is connected to the outer stamp tube 1 by gluing or the like.
  • a set screw is shown at 43 (FIGS. 1 and 2).
  • Valve control pin 38 and control piston 40 can also be made in one piece, for. B. be integrally formed in terms of material. In this case, the control piston 40 can be extended downward in the direction of the valve control fork 36.
  • the valve control pin 38 and the valve control pin guide 39 are arranged in a valve holding bush 44 which is located in a bore in the piston 3.
  • the reference numeral 45 indicates a stroke limiting valve overall (FIGS. 1, 2).
  • the longitudinal axis 46 of the stroke limiting valve 45 runs parallel and at a distance from the longitudinal axis 11 of the hydraulic pit ram.
  • a pressure relief valve 47 (FIG. 3) is arranged coaxially with the stroke limiting valve 45, the function of which will be described below in connection with the function of the stroke limiting valve 45.
  • Reference numeral 48 denotes a hexagon nut (Fig. 1, 2).
  • the control piston 40 of the stroke limiting valve 45 (FIG. 3) essentially consists of two longitudinal sections 49 and 50, which are integrally connected to one another in terms of material and are centrally penetrated by a cylindrical channel 51 (bore).
  • the length section 50 is dimensioned much larger than the length section 49.
  • the length section 50 can be 16 mm, while the total length of the control piston 40 represents 25.5 mm.
  • the diameter of the channel 51 is 5 mm in the illustrated embodiment, while the outer diameter A is larger than the outer diameter B.
  • the outer diameter A can be 8 mm, while the outer diameter B is 7 mm.
  • the length section 50 has bores 52 arranged at uniform distances from one another over the circumference.
  • six such bores of 2.2 mm each are provided, the longitudinal axes of which are orthogonal to the longitudinal axis 53 of the control piston 40.
  • the longitudinal axes of the bores 52 intersect at a point on the longitudinal axis 53 of the control piston 40.
  • the end face of the length section 49 which is larger in diameter, is rounded (FIG. 8), while the control piston 40 is provided with teeth at its other end section.
  • This toothing is formed from a plurality of spaced and parallel, axially parallel recesses 54 which in the illustrated embodiment extend over an axial length C of 3 mm and also connect the channel 51 to the outside in a liquid-conducting manner, so that when the valve control fork 36 rests on the control piston 40 liquid can flow through the channel 51.
  • Control piston 40 Due to the different diameters of the Control piston 40 at its two end sections results on the outer end face of the length section 49 a somewhat larger annular area to be acted upon by the liquid pressure, so that the pressure fluid pressure propagating through the channel 51 from the pressure chamber 41 has a tendency to move the control piston 40 in the direction D, so in the closing sense.
  • the control piston 40 is guided in a longitudinally displaceable manner in a guide piece 55.
  • the guide piece 55 is integrally connected in material terms to a housing 64.
  • an annular groove 56 is arranged in the guide piece 55, in which an O-ring 57 is arranged, which lies in a liquid-tight manner on the outer cylinder surface of the control piston 40.
  • annular groove is arranged in the guide piece 55, in which an O-ring 59 is likewise mounted, which produces a liquid-tight connection between the guide piece 55 and a bore 60 in the piston 3.
  • the bore 60 opens into a chamber 61 of larger cross-section which extends in the axial direction of the control piston 40 and opens into a further chamber 62 which is provided with an internal thread 63, into which a housing 64 with an external thread 133 is screwed.
  • the housing 64 is sealed off from the piston 3 by an O-ring 65 which is arranged in an annular groove 66 (FIG. 9) of the housing 64 and is supported in a liquid-tight manner against a wall of an annular extension 132 of the chamber 62.
  • the guide piece 55 is formed in one piece with the housing 64 in terms of material, which overall has an approximately cartridge-shaped design and essentially consists of three length sections E, F and G.
  • the length section F which also has the external thread 133, is dimensioned larger in diameter than the length section G, which has the same diameter on its outer lateral surface over its entire length and is cylindrical.
  • the length section F also has essentially the same diameter over its length section, while the length section E in the area of the length section F is made larger in diameter than in the remaining part of its length. At its length section facing away from the length section F, the length section E is reduced in diameter over the length section H.
  • the length section F is penetrated by a total of eight bores 67 of equal diameter, which run at a distance and parallel to one another with their longitudinal axes over the circumference of the length section F with a uniform angular distance - in the present case 45 ° - are arranged distributed to each other.
  • the bores 67 open approximately in the plane of the outer cylindrical surface of the immediately adjacent length section G, while they are each connected to a valve chamber 68 at their opposite length section.
  • the entire housing 64 is penetrated in the longitudinal axis direction by several holes with different diameters, all of which are connected to one another in a liquid-conducting manner.
  • One of these bores is the valve chamber 68.
  • the bores 69, 70, 71, 72, 73, 74, 75, 76, 77, 78 are connected to this.
  • the bores 67 open out at one end into the chamber 62 and at the other end into the bore 69 which is connected to the valve chamber 68.
  • a drain hole 80 is connected to the chamber 61 and opens into an annular groove 81 (FIGS. 1, 2).
  • the annular groove 81 is in turn connected to the annular space 82, which is formed between the inner circumferential surface of the outer stamp tube 1 and the outer circumferential surface of the inner stamp tube 2.
  • the annular space 82 is connected via the clearance 83 between the collar 42 and the outer cylinder surface of the outer stamp tube 1 to the outside atmosphere, so that escaping liquid can run down on the outer cylinder surface of the outer stamp tube 1 to lie down.
  • a valve spring designed as a compression spring 84 is supported against the larger-diameter end face of the longitudinal section 49 of the control piston 40, which at the other end bears against an end face 85 of a guide 86 (FIG. 7).
  • the compression spring 84 is inserted under prestress and thus has the tendency to load the control piston 40 in the direction D, that is to say in the closing direction, together with the liquid pressure present.
  • the guide 86 according to FIG. 7 has an externally molded hexagon 87 at one end. With the end section having the hexagon 87, a material is integrally connected to a length section which has an external thread 88.
  • the guide 86 In its interior, the guide 86 is provided with a bore 89 of larger diameter over part of the axial length of the longitudinal section which has the external thread 88, to which a bore 90 with a smaller diameter adjoins. Connected to the bore 90 is a ring-shaped one which is larger in diameter than the bore 90 Mige depression 91, which opens out through a bore 92 and a chamfer-shaped countersink of 90 ° to the outside on the front side 93 of the hexagon head 87.
  • An O-ring 94 (FIG. 3) is arranged in the annular groove 91, the function of which is described below.
  • the pressure relief valve 47 which is arranged coaxially to the stroke limiting valve 45, essentially consists of the guide 86, a valve piston 95, a valve spring 96 and the valve chamber 68.
  • the O-ring 94 is located in the annular groove 91
  • the valve piston 95 is tubular and is open on its end face facing the stroke limiting valve 45.
  • the mouth opening is designated by reference number 97.
  • the piston 95 On its end face facing the mouth opening 97, the piston 95 has a stop collar 98, the annular shoulder 99 of which permits a maximum stroke I of the valve piston 95 up to an annular stop shoulder 100 in the guide 86.
  • the guide 86 which is designed as a valve housing, is screwed with its external thread 88 to an internal thread 101 of the longitudinal section F of the housing 64, that is to say the continuation of the valve chamber 68, and is sealed in a fluid-tight manner by means of a seal 102.
  • the seal 102 likewise consists of an O-ring, which is arranged in an annular groove or fillet 103 (FIG. 7) arranged in the longitudinal region formed between the hexagon 87 and the remaining part of the guide 86.
  • the valve chamber 68 is closed by a screw plug 104 on the one end section facing away from the stroke limiting valve 45 so as to be pressure fluid-tight.
  • the screw plug 104 has an external thread 105 with which it is screwed into an internal thread 106 of the housing 64 and is sealed in a fluid-tight manner by a seal 107.
  • the screw plug 104 is secured against rotation by a dowel pin 108.
  • the reference numeral 109 denotes a central bore through which a suitable tool, e.g. B. an Allen key can be inserted into the cavity formed as a hexagon socket 110.
  • the valve spring 96 is supported with one end against the inside of a centering and sealing extension 111.
  • the centering and sealing extension 111 is also provided with an external thread 112 which can be screwed into a corresponding internal thread of the screw plug 104.
  • the dowel pin 108 secures the finally fixed position of the centering and sealing extension, so that it cannot come loose in the screw plug 104.
  • the valve spring 96 is supported with its end section facing away from the centering and sealing extension 111 against a spring plate 113.
  • This spring plate 113 is provided with a flow bore 114 and on its underside with a conical contact surface 115, against which the hemispherical spring-side end 116 (FIG. 4) of the valve piston 95 bears.
  • the valve piston 95 has a relatively wide axial bore 117, which ends at 118 as a blind bore. Below the blind bore 118, a total of eight radial bores 119 branch off from the axial bore 117 in the present case.
  • valve control pin 38 When the predetermined extension length of the outer stamp tube 1 and the inner stamp tube 2 is reached, the valve control pin 38 is moved in the axial direction, namely in the direction of the crown head 8, via the control cam 32 and the valve control fork 36.
  • the valve control pin 38 abuts the control piston 40 and moves it axially against the direction D against the restoring force of the hydraulic fluid pressure on the pressure-effective ring face and against the restoring force of the compression spring 84 until the bores 52 pass over the O-ring 57. Even before that, when the O-ring 57 is swept for the first time, there is a certain pressure relief.
  • pressure fluid flows through the bore 51 of the control piston 40 and via the bores 52 into the chamber 61 and from here via the drain bore 80 into the annular space 82 and from there via the drain 83 into the outside atmosphere.
  • the pressure fluid pressure also propagates from the chamber 61 via the bores 67 into the valve chamber 68.
  • the pressure fluid pressure propagates through the channel 51 into the axial bore 117 of the valve piston 95.
  • valve piston 95 When a predetermined setpoint pressure is exceeded, the valve piston 95 is pressurized through the bore 51 of the control piston 40, that is to say from the inlet side. Since the O-ring 94 in this position of the bore 90 of the Valve housing 86 is sealed against the valve piston 95, the valve piston 95 is raised with increasing pressure. The radial bores 119 pass over the O-ring 94 so that pressure fluid can flow out of the radial bores 119 to the outlet side, that is to say into the valve chamber 68 and from here via the bores 67, the chamber 61 and the drain bore 80 and the annular space 82. The liquid is released into the open via game 83. This reduces the pressure of the hydraulic fluid on the inlet side of the pressure relief valve.
  • valve spring 96 presses the valve piston 95 in the direction of the input side via the spring plate 113 until the radial bores 119 have again passed over the O-ring 94 and a new seal between the axial bore 117 in the guide or in the valve housing 86 and the outer wall of the valve piston 95 is present.
  • valve housing 86 and the valve piston 95 are illustrated on a larger scale in FIGS. 4 and 5.
  • the illustrated closed position of the pressure relief valve there is a fit h7 / H7 plus the corresponding dimensions of wear of the working methods belonging to this fit (DIN 7163 and DIN 7164) between the outer wall 121 of the valve piston 95 and the bore 90 in the guide 86.
  • the O-ring 94 behaves like a plastic mass under the pressure of the pressure fluid - as shown in FIG. 5 - it also penetrates into a gap 123 with a thin film 122.
  • the edge 124 of the annular groove 91 located at this point is formed with sharp edges and the gap 123 is kept as small as possible. Because with increasing film 122, the friction between the bore 90 of the valve housing or the guide 86 and the outer wall 121 of the valve piston 95 increases.
  • the thin film 122 of the O-ring 94 is also relieved, which relax in the openings of the radial bore 119 can. For this reason, as many radial bores as possible - in the present case eight radial bores 119 - were arranged.
  • the length of the open circumferential line at the radial bore H119 is greater than the length of the closed circumferential line between the individual radial bores 119. Due to the total of eight radial bores 119, the relatively large axial bore 117 and the small stroke I of at most approx. 4.5 mm, the pressure fluid on the inlet side of the pressure relief valve is relaxed within a short opening time. 6, the film 122 of the O-ring 94 is relieved because the circumferential line of the radial openings 119 in this area is longer than the circumferential line of the sum of the two in between webs 131 is located.
  • the valve consisting of the pressure relief valve 47 and the stroke limiting valve 45 is arranged as an interchangeable unit in the housing 64 as a compact assembly.
  • the O-ring 94 has a Shore hardness of preferably about 100 Shore hardness A.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Safety Valves (AREA)
EP91104019A 1990-08-16 1991-03-15 Etançon de mine hydraulique à régulation en longeur télescopique Withdrawn EP0471145A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE9011887U 1990-08-16
DE9011887U DE9011887U1 (de) 1990-08-16 1990-08-16 Teleskopförmig längenverstellbarer hydraulischer Grubenstempel

Publications (1)

Publication Number Publication Date
EP0471145A1 true EP0471145A1 (fr) 1992-02-19

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EP91104019A Withdrawn EP0471145A1 (fr) 1990-08-16 1991-03-15 Etançon de mine hydraulique à régulation en longeur télescopique

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DE (1) DE9011887U1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4221941A1 (de) * 1992-07-03 1994-01-05 Ruhrkohle Ag Hydraulischer Grubenstempel
GB2359609A (en) * 2000-01-06 2001-08-29 Renold Plc A pressure relief valve

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4319967C2 (de) * 1993-06-17 2003-08-21 Vos Richard Grubenausbau Gmbh Druckbegrenzungsventil für den hydraulischen Ausbau im untertägigen Berg- und Tunnelbau

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1211633A (fr) * 1957-09-06 1960-03-17 Dowty Mining Equipment Ltd Soupapes hydrauliques
DE3314837A1 (de) * 1982-06-03 1983-12-08 Jörn 4320 Hattingen Dams Druckbegrenzungsventil
DE8437091U1 (de) * 1984-12-19 1985-08-08 GAT Grubenausbau GmbH, 5840 Schwerte Druckbegrenzungsventil mit geringen Schließwerten
WO1990014500A1 (fr) * 1989-05-19 1990-11-29 Richard Voss Grubenausbau Gmbh Soupape de limitation de pression comportant un piston a gradins ou un double piston

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1211633A (fr) * 1957-09-06 1960-03-17 Dowty Mining Equipment Ltd Soupapes hydrauliques
DE3314837A1 (de) * 1982-06-03 1983-12-08 Jörn 4320 Hattingen Dams Druckbegrenzungsventil
DE8437091U1 (de) * 1984-12-19 1985-08-08 GAT Grubenausbau GmbH, 5840 Schwerte Druckbegrenzungsventil mit geringen Schließwerten
WO1990014500A1 (fr) * 1989-05-19 1990-11-29 Richard Voss Grubenausbau Gmbh Soupape de limitation de pression comportant un piston a gradins ou un double piston

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4221941A1 (de) * 1992-07-03 1994-01-05 Ruhrkohle Ag Hydraulischer Grubenstempel
GB2359609A (en) * 2000-01-06 2001-08-29 Renold Plc A pressure relief valve

Also Published As

Publication number Publication date
DE9011887U1 (de) 1990-12-20

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