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
  • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
  • F04B9/08—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
  • F04B9/10—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid
  • F04B9/109—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers
• • 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
  • F04B15/00—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts
  • F04B15/02—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts the fluids being viscous or non-homogeneous
• • 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
  • F16J1/00—Pistons; Trunk pistons; Plungers
  • F16J1/005—Pistons; Trunk pistons; Plungers obtained by assembling several pieces
  • F16J1/006—Pistons; Trunk pistons; Plungers obtained by assembling several pieces of different materials
  • F16J1/008—Pistons; Trunk pistons; Plungers obtained by assembling several pieces of different materials with sealing lips

Definitions

• the invention relates to a piston pump for conveying thick material, in particular fresh concrete, with at least one delivery cylinder, with a centrally movable in the delivery cylinder with radial clearance to form an annular gap, axially movable delivery piston, wherein the delivery piston a has a central piston frame, radially in the direction of Zylin- inside surface pointing, the annular gap bridging guide means and a frontally fixed by means of a clamping element on the piston frame, one against the cylinder inner surface fitting and pointing with its end face in the conveying direction piston sleeve.
• Piston pumps of this type are used, for example, for conveying industrial thick materials or fresh concrete.
• thick matter pumps have two delivery cylinders whose front-side openings open into a material feed container and are alternately connectable to a delivery line during a delivery stroke, for example via a diverter valve and are open during a filling stroke while the material is being drawn to the material supply container.
• the pistons of the delivery cylinders are driven by hydraulic drive cylinders in push-pull.
• the delivery pistons are connected via a common piston rod with the piston of the drive cylinder.
• the delivery pistons are directly in contact with the conveyed material. Accordingly, the piston seals and the inner surfaces of the delivery cylinders are subjected to high stress and are subject to wear.
• the usually consisting of a metal body piston scaffold serves as a link between the piston drive and the conveyed for receiving and passing the forces generated during pumping.
• the guide means ensure a directionally accurate running of the delivery piston in the delivery cylinder and prevent in conjunction with the piston sleeve tilting of the delivery piston especially when pushing out the conveyed.
• the task of the piston sleeve is divided into two parts in the known piston pumps: First, it serves both during the filling stroke and during the delivery stroke for sealing the necessary for the movement of the piston in the cylinder annular gap. On the other hand, the piston sleeve seals the clamping element, also referred to as the piston flange, toward the piston frame and thus prevents the ingress of conveyed material into the piston.
• both sealing functions are usually realized by a sealing gap which is as long as possible and strongly compressed.
• the sealing collar at both sealing points is designed so that it rests flat over a longer distance on the cylinder wall or on the piston flange and in the uninstalled state has a significant excess. The latter leads in the mounted state to the compression necessary for achieving the sealing function.
• a delivery pressure builds up in the delivery cylinder, which acts as an axially acting surface load on the piston cuff.
• the piston sleeve is supported in the axial direction on the piston frame.
• the surface load on the piston sleeve changes its sign; the negative pressure tries to lift the piston seal from the piston frame.
• the purpose of the clamping element here is to support the piston sleeve in such a way that lifting is prevented.
• the piston seal must be made sufficiently solid and pressed against the delivery cylinder, so that deformation around the clamping element is excluded around.
• the present invention seeks to improve the piston pump of the type specified in that the friction losses are reduced to the delivery piston while maintaining good sealing properties.
• the solution according to the invention is based primarily on the idea that the long sealing gap, together with the necessary compression in the area of the piston sleeve, is replaced by a piston collar which has a neck portion with a smaller outside diameter than the cylinder inner surface and a lip-like protrusion over the neck portion against the cylinder inner surface Having under bridging the annular gap fitting and pointing with its end face in the conveying direction stripping.
• a significantly lower compression is required.
• the stripping section has at least two annularly spaced sealing lips arranged at an axial distance from one another and resting against the cylinder inner surface.
• the piston piston cuff on its neck near the cylinder inner surface form-fitting with the piston frame, the adjacent guide means or a correspondingly designed other Part of the piston is connected. This ensures that the lifting surface load due to the negative pressure in the delivery cylinder at the most critical point near the cylinder wall can be recorded and forwarded to the supporting elements of the delivery piston.
• the piston cuff has on its neck part a radially outwardly open circumferential annular groove, into which engages a piston ring on the arranged, radially inwardly facing circumferential annular rib.
• this can also be achieved by the fact that the piston frame has a radially inwardly open circumferential annular groove into which engages a circumferential annular rib pointing radially outward on the piston sleeve in the region of its neck.
• a further stabilization of the piston sleeve on the piston frame can be achieved in that the piston frame has a frontally open ring receiving, in which the piston sleeve engages with a part of her neck area.
• the clamping element is provided with an annular flange which rests against the end face of the piston sleeve, leaving the Abstreifpartie and thereby presses the piston sleeve against the piston frame.
• the piston frame can one of the clamping element Have bridged central cavity, wherein the clamping element can be fixed by means of a cavity centrally penetrating the clamping screw on the piston frame.
• the guide means are inserted into at least one radially outwardly open circumferential groove of the piston stand. A particularly good sealing function is achieved when the guide means and / or the piston sleeve made of an elastomeric material.
• the piston frame is at least partially made of an elastomeric material, wherein the guide means form an integrally connected to the piston frame guide portion.
• the delivery piston is connected on its side facing away from the conveyed material in the region of its piston frame with a drive mechanism.
• the drive mechanism is advantageously designed as a hydraulic drive cylinder, the drive piston is connected via a piston rod to the delivery piston.
• FIG. 1 shows a diagram of a two-cylinder piston pump for the delivery of thick materials
• Fig. 2a shows an enlarged section of the delivery cylinder after
• Fig. 1 with a first embodiment of the delivery piston in a sectional view
• FIG. 2b shows an enlarged detail from FIG. 2a; FIG. Fig. 3 to 5 representations corresponding to Fig. 2a for three further embodiments of the delivery piston.
• the piston pump shown in Fig. 1 is intended for the promotion of thick material-like conveyed 1 1, in particular of fresh concrete. It consists essentially of two delivery cylinders 10, 10 'whose front-side openings 12, 12' open into a material feed container 14 and alternately during the delivery stroke D (pressure stroke) via a diverter valve 16 with a delivery line 18 connectable and during the Grehubs S ( Suction stroke) under suction of the material to the material feed container 14 are open.
• the delivery cylinders 10, 10 ' are driven by hydraulic drive cylinders 20, 20' in push-pull.
• the delivery pistons 21, 21 ' are connected to the drive pistons 24, 24' via a common piston rod 22, 22 '.
• a water tank 26 In the area between the delivery cylinders 10, 10 'and the drive cylinders 20, 20' there is a water tank 26 through which the piston rods 22, 22 'pass.
• the delivery cylinders 10, 10 ' are open to the water box 26 out. Accordingly, the delivery piston 21, 21 'is acted upon on its rear side with the liquid from the water tank 26. Thus, both the mud passing through the delivery pistons 21, 21 'to the rear are washed away and a cooling effect is generated.
• the measuring probes respond to the drive pistons 24, 24 'passing in the course of the conveying and filling strokes and emit a digitally evaluable end position signal in the area of the switching points.
• a mechanical or electro-mechanical drive mechanism for the delivery pistons.
• a special feature of the invention is the special construction of the delivery piston 21, 21 ', whereby a reduction of the friction effect and thus the wear effect and a reduction of the driving forces in the region of the delivery cylinder 10, 10' to be achieved.
• the delivery pistons 21 shown in FIGS. 2 to 5 coincide with a central piston frame 36, which acts as a link between the piston drive on the side of the piston rod 22 and the high-pressure material under the delivery pressure on the side of the conveyed material 1 1 for transferring the fluid produced during pumping Forces are acting.
• the guide means 40 expediently consist of an elastomeric plastic, for example of polyurethane or polyethylene or derivatives thereof.
• a piston collar 46 which is fixed on the front side in the conveying direction by means of a clamping element 44 on the piston frame 36 is provided.
• the piston sleeve 46 in conjunction with the guide means 40, prevents tilting of the delivery piston 21, in particular during the delivery stroke.
• Another function of the piston sleeve 46 is in the sealing of the necessary for the movement of the delivery piston 21
• the piston sleeve 46 seals the clamping element 44 from the piston frame 36 out and thus prevents the penetration of conveyed material 1 1 in the delivery piston 21st
• the two points at which the conveyed material 1 1 tries to penetrate are indicated in FIGS. 2 to 5 in the form of a plurality of arrows 48.
• the piston sleeve is expediently made of a rubber-elastic material, for example made of NBR (natural butadiene rubber).
• the piston frame 36 consists predominantly of a metal, for example aluminum or an aluminum alloy.
• the piston frame 36 contains a central cavity 42, which is covered by the clamping element 44 designed as an annular flange and is sealed against ingress of liquid by means of a piston collar 46.
• the clamping element 44 is clamped by means of a clamping screw 50 while interposing a part of the piston sleeve 46 on the piston frame 36.
• a peculiarity of the embodiment shown in Fig. 5 is that the piston frame 36 in its entirety consists of an elastomeric plastic and that the guide means 40 'are an integral part of the piston frame.
• the piston sleeve 46 in all four embodiments, a neck portion 52 with respect to the cylinder inner surface 54 smaller outer diameter and a front over the neck portion 52 projecting, against the cylinder inner surface 54 while bridging the annular gap 38 and abutting with its end face in Has conveying direction facing lip-like Abstreifpartie 56.
• the radial sealing takes place via two rib-like sealing lips 58, which abut annularly on the cylinder inner surface 54.
• a significantly lower compression is required than in the previously known two-dimensional contact. conditions of the piston sleeve.
• the piston sleeve 46 is connected in a form-locking manner to the piston frame 36 close to the cylinder inner surface 54. Thereby, the lifting surface load from the negative pressure in the delivery cylinder 10 is received at the critical point near the cylinder wall and forwarded to the supporting elements of the piston frame 36. In terms of design, this is achieved, above all, by the fact that the piston sleeve 46 has a circumferential groove 60 which opens radially outwards at its neck 52 and into which a circumferential annular rib 62 arranged radially inwardly on the piston frame 36 engages.
• the piston stand 36 has a radially inwardly open encircling second annular groove 64 into which engages a circumferential second annular rib 66 which points radially outward on the piston cuff 46 in the region of its neck area.
• the piston frame 36 has an open end ring receiver 68 into which the annular collar 46 engages with a part of its neck portion 52.
• the ring receiver 68 is radially open edge to the cylinder inner surface 54, so that the piston sleeve 46 with its neck portion 52 through the Edge opening 70 has radially outward and directly to the cylinder inner surface 54 faces.
• the invention relates to a piston pump for conveying thick material conveyed, in particular fresh concrete.
• the piston pump has at least one delivery cylinder 10 and one in the delivery cylinder 10 with radial clearance to form an annular gap 38 centrally arranged, axially movable delivery piston 21.
• the delivery piston 21 comprises a central piston frame 36, radially in the direction of the cylinder inner surface 54 facing, the annular gap 38 bridging guide means 40 and a frontally fixed by means of a clamping element 44 on the piston frame 36, a te against the cylinder inner surface 54 and pointing with its end face in the conveying direction pointing piston sleeve te 46.
• the piston sleeve 46 a neck portion 52 with respect to the cylinder inner surface 54 of smaller outer diameter and a front over the neck portion 52 on - Having, against the cylinder inner surface 54 with bridging the annular gap 38 fitting and pointing with its end face in the conveying direction lip-like stripping section 56.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Reciprocating Pumps (AREA)
• Details Of Reciprocating Pumps (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=48577731

Family Applications (1)

Country Status (2)

Cited By (5)

Citations (6)

Family Cites Families (6)

• 2012
  • 2012-06-29 DE DE201210211280 patent/DE102012211280A1/de not_active Withdrawn
• 2013
  • 2013-05-31 WO PCT/EP2013/061273 patent/WO2014001020A1/fr not_active Ceased

Patent Citations (6)

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