EP0697066B1 - Reciprocating pump - Google Patents

Abstract

A reciprocating pump to deliver semifluid media, such as paints, flooring plasters, wall plasters and the like, has one or more cylinders, each containing a piston. The cylinders are driven by a motor, on the drive shaft of which a round disk is eccentrically mounted. The connection with the piston is provided by a connecting rod, which at one end rest on the round eccentric disk and at the other is connected with a rod of the piston. A guide device guides the connecting rod parallel to the longitudinal axis of the cylinder.

Description

The present invention relates to a thick matter pump for conveying viscous media, such as mortar, concrete, screeds, paints and plasters, both mineral structure and dispersion plasters and the like.

The thick matter pump according to the invention is described below in relation to its use as a mortar pump. However, it is pointed out that the design according to the invention can also be used for thick matter pumps which are provided for conveying other media.

Mortar pumps are used to move mortars, such as cement mortar, concrete spray mortar, basic plaster mortar, insulating plaster mortar, fire protection mortar and the like Wall is sprayed to promote. A typical known mortar pump has a delivery rate of approx. 20-50 1 / min and a delivery pressure from up to 40 bar. A hose and / or pipeline is used to convey it to the place of use.

It is known in the prior art to design such a mortar pump as a double piston pump with two horizontally arranged cylinders lying next to one another. These thick matter pumps are driven by an electric or internal combustion engine, the speed of which is transmitted to a rotating drive shaft via a gear. Two drive cams, which are offset by 180 ° to one another, are provided on the drive shaft and move the pistons in the conveying direction via the piston rod during the pressure stroke. The piston moves back during the suction stroke via a counter spring designed as a coil spring.

These known thick matter pumps have the disadvantage that they are constructed in a relatively complex manner, have a large construction volume and in particular are heavy. Another disadvantage is that the springs, due to their characteristics, in particular with high coefficients of friction, can cause malfunctions.

The present invention is therefore based on the object of creating a reliably working thick matter pump for conveying viscous media, which is simple, compact and of comparatively low weight and works very reliably.

This object is achieved by the subject matter of claim 1.

Preferred further developments are the subject of the dependent claims.

In the thick matter pump according to the invention, in order to convert the rotary movement of the drive device into the reciprocating movement of the piston, a pair of cams and tappets is not used, as in the prior art, but rather a connecting rod designed and mounted in a special way.

A circular eccentric disk is arranged on a drive shaft, which is driven by a suitable motor via a gearbox, on which a connecting rod is rotatably mounted. The other end of the connecting rod is connected to the piston rod of the pump piston and is guided along the (fictitious) axis of the pump cylinder via a guide device.

This structure has the advantage that the power transmission between the eccentric disc (which has a relatively large diameter) and the connecting rod takes place with a comparatively low surface pressure, so that on the one hand the wear is considerably reduced and on the other hand the structure can be made compact. The spring devices etc. required in the prior art can be completely dispensed with.

Since the piston rod is guided in a guide device, no lateral forces resulting from the drive act on the piston. The piston and the piston rod therefore do not need to be larger than in the prior art.

The connecting rod is rotatably mounted on the eccentric disc preferably by means of a roller bearing. This simplifies the construction since such rolling bearings are available as standard components and also makes it possible to transmit high and very high torques via the connecting rod. A deep groove ball bearing, a needle bearing or a cylindrical roller bearing is preferably used as the rolling bearing.

Alternatively, a plain bearing can also be used instead of the roller bearing.

According to a preferred development of the invention, the guide device is designed so that a connecting pin between the piston rod and the connecting rod is provided, the (fictitious) axis of which is arranged perpendicular to the cylinder axis and which is guided in guide grooves.

Rolling bearings whose outer diameter is slightly smaller than that are preferably plugged onto the journal Height of the guide groove so that the outer ring can roll on the respective wall of the guide groove.

This design creates a compact, simple and very reliable thick matter pump which is suitable for the transmission of high and highest torques.

The thick matter pump according to the invention can be constructed with a different number of cylinders. When used as a mortar pump, a two-cylinder thick matter pump is particularly preferred, since a relatively uniform volume flow is achieved here in conjunction with the elastic properties of the delivery hose that is usually used.

The structure of the cylinder, the piston and the valve devices are known in the prior art and need not be explained in more detail here. It should only be pointed out that, when used as a mortar pump, a disk piston is usually used, on which a sealing sleeve is attached, which is made of leather, rubber or the like. The thick matter pump is preferably designed as a single stroke pump, which means that material is pressed into the delivery line only when the piston moves away from the drive shaft.

In one embodiment of the thick matter pump according to the invention, which is constructed as a two-cylinder mortar thick matter pump as described above, the weight could be reduced by more than half compared to the token-operated thick matter pump known in the prior art. This not only results in a considerable saving in material, but also a significant simplification in the handling and transport of corresponding thick matter pumps. In addition, the low weight also makes it possible to connect these mortar pumps directly to the silo outlet of a conventional plaster mortar silo.

Tests have shown that despite a drive torque of 750 Nm (measured on the drive shaft) there was no significant wear on the transmission device.

Fig. 1

eine Seitenansicht einer Dickstoffpumpe gemäß der Erfindung;

Fig. 2

eine Aufsicht auf das Ausführungsbeispiel gemäß Fig. 1 ohne Antriebsmotor;

Fig. 3

eine teilweise geschnittene Darstellung des Ausführungsbeispieles gemäß Fig. 1;

Fig. 4

eine Aufsicht auf die Führungseinrichtung beim Ausführungsbeispiel gemäß Fig. 1 und 2; und

Fig. 5

eine Seitenansicht der Führungseinrichtung gemäß Fig. 4.

The invention will now be further described using exemplary embodiments. It shows in a schematic way:

Fig. 1

a side view of a thick matter pump according to the invention;

Fig. 2

a plan of the embodiment of Figure 1 without a drive motor.

Fig. 3

a partially sectioned illustration of the embodiment of FIG. 1;

Fig. 4

a plan of the guide device in the embodiment of FIGS. 1 and 2; and

Fig. 5

3 shows a side view of the guide device according to FIG. 4.

1 to 5 schematically show an embodiment of the present invention. This exemplary embodiment is a two-cylinder mortar pump which has a housing 1 in which the pistons and a transmission device are arranged.

The two cylinders 3, 4 are arranged horizontally next to one another (in the position of use of the device) and each have a (fictitious.) Cylinder axis 6 and 7, respectively.

A piston 8, which is designed as a disk piston and is connected to a piston rod 9, is arranged in each of the two cylinders. The (fictitious) cylinder axis of the cylindrical piston rod 9 coincides with the cylinder axis of the cylinders 6 and 7, respectively.

A sealing sleeve is attached to the disc piston, which is pressed onto the cylinder wall by means of an expansion ring. Furthermore, there are valve devices for controlling the suction and pressure stroke and an overpressure safety device intended. However, since the aforementioned devices are all known in the prior art, these parts are neither shown nor explained in detail. In the housing 1, a drive shaft 12 is mounted in bearings 13, 14, which are preferably designed as roller bearings.

A first eccentric disk 15 and a second eccentric disk 16 are fastened on the drive shaft 12. Both eccentric disks are designed as circular disks and are attached to the drive shaft 12 in such a way that an eccentricity "e" results between the (fictitious) axis of rotation 20 of the drive shaft 12 and the center 21 of the eccentric disks. The two eccentric disks are offset from one another by 180 °.

A connecting rod 24, 25 is attached to each of the eccentric disks, both connecting rods having a circular recess 27, as can be seen in FIG. 1. The connection between the connecting rods 24, 25 and the eccentric discs 15, 16 is such that the connecting rod can easily turn against the two eccentric discs even under high loads.

This rotatability can be achieved by using a plain bearing, which preferably enables a hydrodynamic or a hydrostatic or a mixed hydrodynamic / hydrostatic bearing of the connecting rod on the eccentric disc. It is also possible to design the friction partner eccentric disc / connecting rod bore in such a way that a low coefficient of friction and low wear is achieved. This can be done, for example, by manufacturing or coating one of the two friction partners from a suitable material, for example a bearing bronze. Furthermore, a friction-reducing layer such as a Teflon layer can also be used.

Storage by means of a roller bearing, as shown in FIG. 3, is also preferred. In this case, the inner ring 31 of a roller bearing, generally designated 30, is pressed onto the eccentric disk (eccentric disk 17 is shown). The outer ring 32 of this roller bearing is pressed into the bore 27 of the connecting rod 25. Since the connection between the eccentric disc and the connecting rod is only loaded radially, but not axially, the pressing forces are sufficient to effect a secure connection between the eccentric disc and the connecting rod. If this should cause problems in individual cases, it is also possible to provide appropriate fastening devices, for example appropriately designed snap rings, in order to prevent the individual parts from axially shifting relative to one another.

In the exemplary embodiment, a grooved ball bearing was chosen as the rolling bearing, since this can absorb axial forces and thus can reliably prevent axial displacement of the individual parts relative to one another. Instead of a deep groove ball bearing a needle roller bearing, a cylindrical roller bearing or, in the case of high loads, a spherical roller bearing can also be used.

The eccentric discs must be arranged on the drive shaft 12 in a rotationally fixed manner. This can be done with a feather key, which is arranged in a groove in the drive shaft and engages in a corresponding groove in the eccentric disc. With a feather key, however, another shaft-hub connection (known in the prior art), for example a spline, can be used. In the interest of a simple structure, it is also possible to weld the eccentric disks to the drive shaft, but precautions must then be taken in order to be able to install the drive shaft 12 with the bearings 13 and 14 in the housing 1.

1, the axis of the drive shaft 12 is offset in height with respect to the longitudinal axes 6, 7 of the cylinders 3, 4, the offset (cf. FIG. 1) corresponding to the distance "h". On the one hand, this offset has advantages with regard to the spatial design, since the thick matter pump can thereby be finished as a whole with a flat construction.

Furthermore, this design has the advantage that the power transmission from the connecting rod to the piston rod takes place at a more favorable angle during the pressure stroke, so that the Proportion of the transverse force directed perpendicular to the cylinder axis is lower.

The guidance of the connecting rod by the guide device will now be described in detail with reference to FIGS. 4 and 5.

In its front area facing away from the eccentric disc, the connecting rod has a bore 40 in which a pin 41 is movably guided. The piston rod 9 is fork-shaped in its front area and also has a bore 43 into which the pin 41 is pressed firmly. The pin 43 is extended beyond the piston rod 9 on both sides and carries a roller bearing 45 and 46 at its respective ends 41a, 41b. The roller bearings 45, 46 each have an inner ring which is pressed firmly onto the pin 41, and an outer ring. Balls are preferably used as rolling elements, but it is also possible to use cylindrical rollers, pendulum rollers or needles. The use of plain bearings is also advantageous.

An upper guide track 50 and a lower guide track 52, 53 are arranged on each side of each connecting rod. These guideways form an essentially flat bearing surface on which the outer ring of the roller bearings 45, 46 can roll. This requires that the distance a (see Fig. 5) of the upper to the lower guideways is at least slightly larger than the outer diameter of the roller bearings 45, 46.

The length "1" of the guideways is dimensioned such that the roller bearings 45, 46 rest on the respective guideways during the entire stroke of the piston.

In the exemplary embodiment according to FIG. 5, a plate 56 is provided which is fastened in the housing parallel to the plane of the connecting rod 24, a total of four plates being required in the double thick matter pump according to the exemplary embodiment explained here. A slot 58 is provided in each plate, the length 1 and height a of which meet the criteria discussed above.

Instead of such a slot, the guideways can also be designed in other ways, for example by appropriately designed U-bars, etc.

It should be noted that the support of the transverse forces resulting from the movement of the bolt via a roller bearing is the preferred embodiment of the invention. However, it is also possible to absorb the transverse forces via other longitudinal guides, for example via a sliding guide or the like.

The exemplary embodiment illustrated with reference to FIGS. 1 to 5 is intended for a speed of 50 min ^-1 and a delivery volume of 20 to 40 l / min work. With this design, a drive torque of up to approx. 700 Nm is required. Depending on the design and application, other values are also possible.

An electric motor, an internal combustion engine, preferably a diesel engine or a pneumatically operated motor (e.g. in a potentially explosive atmosphere) is used for the drive, the output speed of which, if necessary, is reduced to the input speed via a suitable gear. In order to adapt the delivery volume of the thick matter pump to the respective working conditions, the drive can be designed to be variable in speed. There are several options for changing the speed:

A first possibility is to influence the output speed of the motor in a corresponding manner. In the case of an electric motor, this can be effected continuously by changing the frequency or, in the case of a DC machine, by changing the excitation voltage. A stepped change in speed can also be brought about in an electric motor by changing the pole.

In the case of an internal combustion engine, it is possible to intervene directly in the fuel supply for speed control.

In all of the motor types mentioned, the speed change can also be implemented by means of a manual transmission, in that gears are brought into engagement with one another in different ways, or are rotatable or non-rotatable with a wave to achieve different translations. Furthermore, it is also possible to use a gear with a continuously variable transmission ratio (adjusting gear) both in cooperation with an electric motor and with an internal combustion engine.

In a very simple further embodiment of the invention, in order to change the rotational speed, it is provided that the drive shaft is not flanged directly to the motor, as is indicated in FIG. 2 by the drive shaft and the key shown there, but with two or more pulleys on the drive shaft to put on different diameters, and to provide appropriate pulleys on the drive shaft of the motor. The speed can then be changed easily by moving the belt from one pulley to the other. A corresponding chain drive can also be used.

In order to facilitate the transport and handling of the thick matter pump, the housing can be provided with wheels so that the thick matter pump can be attached to a towing vehicle, for example, or pushed in a simple manner.

It is also possible to provide a holding device on the housing of the thick matter pump, with which the thick matter pump directly at the outlet of a ready-mixed mortar container, For example, a silo can be arranged. This allows the mortar to be conveyed efficiently to the respective application site.

Claims (19)

1. A thick material pump for conveying viscous media such as mortar, concrete, stonefloors, colors, mineral plasters, dispersion plasters and the like, comprising:

   at least one cylinder (3, 4),

   a piston (8) being movably arranged in said cylinder (3, 4),

   a drive means including a rotating drive shaft and having a means for converting the rotational movement of said drive shaft into that alternating movement of said piston (8),

   characterised in that

   said means for converting the rotational movement into an alternating movement comprise a round excentric disc (15, 16) which is excentrically attached to that drive shaft and rotates together with it, and

   a connecting rod (24) is provided which has a bore (27) at its first end by means of which the connecting rod is rotatably supported on that excentric disc (15, 16) and which has its second end connected to a piston rod (9) of said piston (8), and

   a guide means (45, 46, 56) by means of which said second end of said connecting rod is guided in a direction in parallel to the longitudinal axis (6, 7) of said cylinder (3, 4).
2. The thick material pump according to claim 1, characterised in that the rotatable support between the excentric disc (15, 16) and said bore (27) of the connecting rod (24) is provided by a roller bearing (30).
3. The thick material pump according to claim 1 or 2, characterised in that said connecting rod (24) and said piston rod (9) are connected by means of a plug (41), wherein either said connecting rod or said piston rod is designed such in a connecting region that said one part embraces said other part in form of a fork.
4. The thick material pump according to claim 2 or 3, characterised in that the plug comprises a (fictitious) longitudinal axis which is vertically arranged with respect to said (fictitious) cylinder axis (6, 7) of said cylinder and that at least a lower and an upper guiding path is provided by which said plug is guided during said alternating movement of that piston rod.
5. The thick material pump according to claim 4, characterised in that both ends of said plug (41) are guided by an upper and a lower guiding path.
6. The thick material pump according to claim 5, characterised in that a roller bearing (45, 46) is provided on both ends of said plug whose outer ring rolls on said lower or said upper guiding path independently of the movement direction.
7. The thick material pump according to claim 5, characterised in that the guidance of said plug is arranged as a sliding guidance.
8. The thick material pump according to one of claims 4 to 6, characterised in said that guiding paths are formed as grooves arranged in plates which are vertically attached with respect to said (fictitious) longitudinal axis of said plug (41) in a housing (1) of that thick material pump.
9. The thick material pump according to at least one of claims 1 to 7, characterised in that the piston is designed as a disc piston and that a sealing means, preferably a sealing sleeve, is provided which seals said piston with respect to that cylinder.
10. The thick material pump according to at least one of claims 1 to 9, characterised in that two cylinders arranged in parallel to each other are provided, and two excentric discs displaced with respect to each other are provided on said drive shaft, which are coupled to said pistons in said cylinders via a respective connecting rod.
11. The thick material pump according to claim 10, characterised in that said cylinders (in operating position) are horizontally arranged.
12. The thick material pump according to at least one of claims 1 to 11, characterised in that said drive shaft is connected to an electromotor, to a combustion engine or to a pneumatically operated motor via a gearing.
13. The thick material pump according to claim 12, characterised in that means are provided for controlling and/or regulating the rotational speed of said motor.
14. The thick material pump according to claim 12 or 13, characterised in that said gearing is a gearshift gearing by which the transmission of the rotational movement from said motor to said drive shaft can be gradually changed.
15. The thick material pump according to claim 12 or 13, characterised in that the gearing is a gearing having a continously variable transmission.
16. A thick material pump according to at least one of claims 1 to 15, characterised in that at least two wheels are arranged at the housing (1) of said thick material pump.
17. The thick material pump according to at least one of claims 1 to 16, characterised in that holding means are provided by means of which said thick material pump is directly connectable at the outled of a storage bunker, such as a silo, a container an the like.
18. Use of said thick material pump according to at least one of claims 1 to 17 for conveying mortar, particularly cover mortar and/or colors and/or stonefloors.
19. Use of said thick material pump according to at least one of claims 1 to 17 for conveying finish mortar which is extracted from a receptacle, e.g. a silo receptacle.

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