EP0697066A1

EP0697066A1 - Reciprocating pump

Info

Publication number: EP0697066A1
Application number: EP94915567A
Authority: EP
Inventors: Friedrich Schwald; Josef Schwall
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-05-02
Filing date: 1994-05-02
Publication date: 1996-02-21
Anticipated expiration: 2014-05-02
Also published as: WO1994025757A1; CZ253495A3; DE4314132A1; DE59401274D1; EP0697066B1; PL173575B1; ATE146258T1; PL311302A1

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

Piston pump

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

The piston 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 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, from a first point, to which the mortar is delivered or manufactured, to a second point, to a second point cher the mortar is sprayed onto a wall, for example. A typical known mortar pump has a delivery rate of approx. 20-50 1 / min and a delivery pressure of 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 pumps are driven by an electric or internal combustion engine, the speed of which is transmitted to a rotating drive shaft via a gear. On the drive shaft there are two drive cams which are offset by 180 ° to one another and move the pistons in the conveying direction via a piston rod during the pressure stroke. The piston moves back during the suction stroke via a counter spring designed as a helical spring.

These known piston pumps have the disadvantage that they are of relatively complex construction, have a large construction volume and in particular are heavy. A further disadvantage is that the springs, due to their characteristics, in particular with high coefficients of friction, can cause operational disturbances.

The present invention is therefore based on the object of creating a reliably operating piston pump, in particular for conveying viscous media, which is of compact construction and which has a comparatively low weight.

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

Further preferred developments are the subject of the subclaims.

In the piston 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 grooved 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 such that a connecting pin is provided between the piston rod and the connecting rod, 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 the height of the guide groove are preferably plugged onto the journal, so that the outer ring can roll on the respective wall of the guide groove.

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

The piston pump according to the invention can be constructed with a different number of cylinders. When used as a mortar pump, a two-cylinder 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 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 piston pump according to the invention, which, as described above, as two cylindrical mortar piston pump, the weight could be reduced by more than half compared to the cam-operated piston pump known in the prior art. This not only results in a considerable saving in material, but also in a significant simplification of the handling and transportation of corresponding 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.

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

The invention will now be further described on the basis of exemplary embodiments. This shows in a schematic way:

Figure 1 is a side view of a piston pump according to the invention.

FIG. 2 shows a top view of the exemplary embodiment according to FIG. 1 without a drive motor;

3 shows a partially sectioned illustration of the exemplary embodiment according to FIG. 1;

4 shows a top view of the guide device in the exemplary embodiment according to FIGS. 1 and 2; and

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

1 to 5 schematically show an exemplary embodiment of the present invention. This The 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 fastened to the disk piston and is pressed onto the cylinder wall by means of an expansion ring. Furthermore, valve devices for controlling the suction and pressure stroke and an overpressure safety device are provided. 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. Furthermore, it is possible to design the eccentric disc / connecting rod bore friction partner in such a way that a low coefficient of friction and low wear is achieved. This can e.g. done by one of the two friction partners made of a suitable material, for example a bearing bronze, or coated with it. Furthermore, a friction-reducing layer such as a Teflon layer can also be used.

Storage by means of a roller bearing is also preferred, as shown in FIG. 3. 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 loaded only radially, but not axially, the pressing forces are sufficient to bring about 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 displacing one another. the.

In the exemplary embodiment, a grooved ball bearing was chosen as the roller 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 grooved ball bearing, however, a needle bearing, a cylindrical roller bearing or, in the case of high loads, a pendulum 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 construction, 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 configuration, since the pump can thereby be finished as a whole with a flat construction.

This design also has the advantage that the transmission of force 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 region and also has a bore 43 into which the pin 41 is firmly pressed. 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 firmly attached to the Pin 41 is pressed, 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 support surface on which the outer ring of the roller bearings 45, 46 can roll. For this it is necessary that the distance a (see FIG. 5) of the upper to the lower guide tracks 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, with the double piston pump as a whole according to the exemplary embodiment explained here four plates are required. A slot 58 is provided in each plate, the length 1 and height a of which correspond to 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 to work at a speed of 50 min ^" and a delivery volume of 20 to 40 1 / min. With this design, a drive torque of up to approximately 700 Nm required, but other values are also possible, depending on the design and application.

An electric motor, an internal combustion engine, preferably a diesel engine or a pneumatically operated engine (e.g. in a potentially explosive environment) 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 piston 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 an electric motor, this can be done continuously by changing the frequency or, in the case of a DC machine, by a change in 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 gearwheels are brought into engagement with one another in different ways or are connected to a shaft in a rotatable or rotationally fixed manner in order to achieve different gear ratios. Furthermore, it is also possible to use a transmission 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 exemplary embodiment of the invention, in order to change the 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 feather key shown there, but on the drive shaft two or to put on more pulleys with different diameters, and to provide corresponding 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 piston pump, the housing can be provided with wheels so that the piston 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 piston pump with which the piston pump can be arranged directly at the outlet of a ready-mixed mortar container, for example a silo. This allows the mortar to be conveyed rationally to the respective application site.

Claims

1. Piston pump, in particular for conveying viscous media, such as mortar, concrete, screeds, paints, mineral plasters, dispersion plasters and the like

at least one cylinder,

a piston which is arranged displaceably in the cylinder,

a drive device which has a rotating drive shaft and is provided with a device in order to convert the rotating movement of this drive shaft into a reciprocating movement of the piston,

characterized in that

the device for converting the rotating movement into a reciprocating movement comprises a round eccentric disc (15, 16) which is placed eccentrically on the drive shaft and rotates with it, and

a connecting rod (24) has a bore (27) at its first end, with which the connecting rod is rotatably mounted on the eccentric disc (15, 16) and the second end of which is connected to a piston rod (9) of the piston (8) is and

a guide device (45, 46, 56) through which this second end of the connecting rod is guided in a direction parallel to the longitudinal axis (6, 7) of the cylinder (3, 4.).

2. Piston pump according to claim 1, characterized in that the rotatable mounting between the Exzen¬ ter plate (15, 16) and the bore (27) of the connecting rod (24) by means of a roller bearing (30).

3. Piston pump according to claim 1 or 2, characterized gekenn¬ characterized in that the connecting rod (24) and the piston rod (9) are connected by means of a pin (41), with either the connecting rod or the piston rod being designed in the connection area, that one part includes the other part in a fork shape.

4. Piston pump according to claim 2 or 3, characterized gekenn¬ characterized in that the pin has a (fictitious) longitudinal axis which is arranged perpendicular to the (fictitious) cylinder axis (6, 7) of the cylinder and that at least one lower and one upper guide track are provided is through which the pin is guided during the reciprocating movement of the piston rod.

5. Piston pump according to claim 4, characterized in that both ends of the pin (41) are guided by an upper and a lower guide track.

6. Piston pump according to claim 5, characterized in that a roller bearing (45, 46) is provided on both ends of the pin, the outer ring, depending on the direction of movement, rolls on the lower or the upper guide track.

7. Piston pump according to claim 5, characterized in that the guide of the pin is aus¬ forms as a sliding guide.

8. Piston pump according to one of claims 4 to 6, characterized in that the guideways as nu ten are formed, which are arranged in plates which are perpendicular to the (fictitious) longitudinal axis of the pin (41) in a housing (1) of the piston pump.

9. Piston pump according to at least one of claims 1 to 7, characterized in that the piston is designed as a disc piston and that a sealing device, preferably a sealing sleeve, is provided which seals the piston against the cylinder.

10. Piston pump according to at least one of claims 1 to 9, characterized in that two cylinders arranged parallel to each other are provided and two offset eccentric disks are provided on the drive shaft, each connected to the pistons in the cylinders via a connecting rod are.

11. Piston pump according to claim 10, characterized gekennzeich¬ net that the cylinders (in the position of use) are arranged horizontally.

12. Piston pump according to at least one of claims 1 to 11, characterized in that the drive shaft is connected via a gear to an electric motor, an internal combustion engine or a pneumatically operated motor.

13. Piston pump according to claim 12, characterized gekennzeich¬ net that a device is provided to control and / or regulate the speed of the engine.

14. Piston pump according to claim 12 or claim 13, characterized in that the transmission is a gearbox through which the transmission of the rotary movement from the motor to the drive shaft can be changed in stages.

15. Piston pump according to claim 12 or claim 13, characterized in that the transmission is a transmission with continuously variable translation.

16. Piston pump according to at least one of claims 1 to 15, characterized in that at least two wheels are arranged on the housing (1) of the piston pump.

17. Piston pump according to at least one of claims 1 to 16, characterized in that a holding device is provided with which the piston pump directly at the outlet of a storage container, such as e.g. a silo, a container and the like can be attached.

18. Use of the piston pump according to at least one of claims 1 to 17 for conveying mortar, in particular plastering mortar and / or paints and / or screed.

19. Use of the piston pump according to at least one of claims 1 to 17 for conveying ready-mixed mortar, which consists of a container, e.g. a silo container is removed.