EP2805050B1 - Piston pump for a high-pressure cleaning device - Google Patents

Description

The invention relates to a piston pump for a high-pressure cleaning device having a plurality of pump chambers, in each of which a reciprocating piston dips and which are in each case via a suction valve with a suction inlet and a pressure valve with a pressure outlet in fluid communication, wherein the suction valve comprises a Saugventilschließkörper, the is sealingly engageable with a suction valve seat, and wherein the pressure valve comprises a pressure valve closing body, which is sealingly engageable with a pressure valve seat, wherein the pressure valve seat is arranged radially offset to the suction valve seat with respect to a pump longitudinal axis.

Such a piston pump is from the WO 2008/086950 A1 known. With their help, a liquid, especially water, can be pressurized and, for example, directed at a surface or object to clean the surface or object. The piston pump has a plurality of pump chambers, in each of which a piston is immersed. The piston is driven to a reciprocating motion. This has the consequence that the volume of the pump chamber periodically changed and thereby sucked liquid from a suction inlet via a suction valve in the pump chamber, placed in the pump chamber under pressure and then discharged through a pressure valve and a pressure outlet. For example, a supply line can be connected to the suction inlet and, for example, a pressure hose can be connected to the pressure outlet, which carries a discharge element at its free end, for example a spray nozzle or a spray lance.

The piston pump is subject to considerable mechanical stress during its operation, since it has to withstand liquid pressures of over 100 bar. The housing of the piston pump therefore usually has a considerable material thickness. This is especially true for the area between the Saugventilsitzen and the pressure valve seats, since the pump housing is particularly heavily loaded in these areas.

Object of the present invention is to develop a piston pump of the type mentioned in such a way that it has an increased mechanical strength without increasing their material thickness.

This object is achieved in a piston pump of the generic type according to the invention that the pressure valve seat is arranged offset relative to the pump longitudinal axis in the circumferential direction of the piston pump to Saugventilsitz.

Each pump chamber of the piston pump is associated with a Saugventilsitz and a pressure valve seat. Usually, the centers of the suction valve seat and the pressure valve seat are positioned in a common cutting plane of the piston pump, the cutting plane containing the pump longitudinal axis. In departure from such an arrangement, the pressure valve seat is arranged offset in relation to the pump longitudinal axis in the circumferential direction of the piston pump to the suction valve seat in the inventive piston pump. It has been shown that the staggered arrangement of the pressure valve seat gives the piston pump an increased mechanical load-bearing capacity without the material thickness of the piston pump having to be increased for this purpose. If the material thickness remains the same, the liquid to be delivered can thus be pressurized to a higher pressure.

It is advantageous if the pressure valve seat is arranged offset relative to the pump longitudinal axis by an angle of 10 ° to 40 ° to the suction valve seat. In particular, an angle in the range between 20 ° and 30 °, for example 25 °, has proved to be advantageous in order to increase the mechanical load capacity of the piston pump without increasing their material thickness.

Relative to the pump longitudinal axis of the pressure valve seat is conveniently located in the axial direction at the same height as the Saugventilsitz.

Advantageously, the suction valve seat and the pressure valve seat are made of a plastic material.

In an advantageous embodiment, the piston pump has three suction valve seats arranged uniformly distributed about the pump longitudinal axis and three pressure valve seats distributed uniformly around the pump longitudinal axis. The Saugventilsitze are arranged in such an embodiment at an angular distance of 120 ° to each other and also the pressure valve seats have an angular distance of 120 ° to each other. Both the Saugventilsitze and the pressure valve seats thus form the corners of an imaginary equilateral triangle. Here, the center of the imaginary triangle of Saugventilsitze coincides with the center of the imaginary triangle of the pressure valve seats. However, the imaginary triangle of the pressure valve seats with respect to the imaginary triangle of Saugventilsitze is arranged rotated around the piston longitudinal axis. The angle of rotation is favorably 10 ° to 40 °, in particular 20 ° to 30 °, preferably 25 °.

In a particularly preferred embodiment, the piston pump according to the invention comprises a pump block and a pump head, wherein the pump head has the suction inlet and the pressure outlet and the pump block comprises the pump chambers and receives the suction and the pressure valves, and wherein the pump head placed on a triangular edge of the pump block is, wherein the suction valves are arranged in a plan view of the pump block in the corner regions of the edge and the pressure valves are surrounded in a plan view of the pump block within the edge of a cylindrical inner wall. Such a configuration gives the piston pump a particularly high mechanical load capacity without the material thickness of the piston pump having to be considerably increased for this purpose.

The suction valves each have a suction valve passage closable by the suction valve closing body, and a suction valve closing spring which moves the suction valve closing body with a spring force toward the suction valve passage applied. It is advantageous if the Saugventilschließfeder is positioned at an axial distance to the Saugventildurchlass. In such a configuration, the liquid flowing into the pump chamber can flow past the suction valve closing spring laterally, without these having to be flowed through by the liquid. This reduces flow losses in the region of the suction valve closing spring, since the flow loss exerted by the suction valve closing spring can be kept low.

Preferably, the Saugventilschließfeder is arranged in a Saugventilkammer which is in flow communication via the Saugventildurchlass, wherein at a distance from the Saugventildurchlass into the Saugventilkammer a support arm protrudes, on which the Saugventilschließfeder is supported. In known piston pumps, the Saugventilschließfeder supported directly on the Saugventildurchlass and the liquid must flow through the Saugventilschließfeder to get to the Saugventildurchlass. This is not necessary in a development of the invention, since the Saugventilschließfeder supported with its the Saugventildurchlass end facing a support arm, which projects at a distance from the Saugventildurchlass in the Saugventilkammer.

Conveniently, the support arm is radially aligned relative to the piston longitudinal axis.

In an advantageous embodiment of the invention, the suction valve chamber is only partially penetrated by the holding arm, that is to say the holding arm projects freely from the wall of the suction valve chamber, without reaching the diametrically opposite wall region of the suction valve chamber with its free end.

For example, it can be provided that the holding arm projects only approximately to the middle of the suction valve chamber.

It is advantageous if the holding arm forms a guide for the Saugventilschließkörper. This can be prevented in a structurally simple way that the Saugventilschließkörper tilted during a lifting movement.

The holding arm conveniently comprises a passage opening, which is penetrated by the Saugventilschließkörper.

The Saugventilschließkörper may for example be designed mushroom-shaped and comprise a valve plate, which is followed by a valve stem, wherein the valve stem passes through the through hole of the support arm and is guided by the support arm.

It is particularly favorable when the suction valve closing spring is clamped on the side of the holding arm facing away from the suction valve passage between the holding arm and the suction valve closing body. In such a construction, the Saugventilschließfeder supported on the one hand on the side facing away from the suction valve passage side of the support arm and on the other hand on the Saugventilschließkörper. The Saugventilschließkörper may have a spring holder for this purpose. Conveniently, the spring holder is pressed with a shaft of the Saugventilschließkörpers.

Figur 1:

eine schematische Längsschnittansicht einer vorteilhaften Ausführungsform einer erfindungsgemäßen Kolbenpumpe;

Figur 2:

eine Draufsicht auf einen Pumpenblock der Kolbenpumpe aus Figur 1;

Figur 3:

eine Schnittansicht des Pumpenblockes längs der Linie 3-3 in Figur 2;

Figur 4:

eine Schnittansicht eines Saugventiles längs der Linie 4-4 in Figur 3; und

Figur 5:

eine Schnittansicht des Pumpenblockes längs der Linie 5-5 in Figur 2.

The following description of a preferred embodiment of the invention serves in conjunction with the drawings for further explanation. Show it:

FIG. 1:

a schematic longitudinal sectional view of an advantageous embodiment of a piston pump according to the invention;

FIG. 2:

a plan view of a pump block of the piston pump FIG. 1 ;

FIG. 3:

a sectional view of the pump block along the line 3-3 in FIG. 2 ;

FIG. 4:

a sectional view of a suction valve along the line 4-4 in Figure 3; and

FIG. 5:

a sectional view of the pump block along the line 5-5 in FIG. 2 ,

In the drawing, an advantageous embodiment of a piston pump according to the invention is shown schematically, which is generally occupied by the reference numeral 10. It comprises a pump head 12 with a suction inlet 14 and a pressure outlet 16. To the suction inlet 14, a supply line can be connected, via which the piston pump 10 can be supplied under pressure to be set liquid. To the pressure outlet 16, a discharge line can be connected, by means of which the liquid pressurized by the piston pump 10 can be directed onto an object or a surface in order to clean the object or the surface. The discharge line may carry at its free end a delivery member, such as a spray lance or a spray nozzle.

The pump head is mounted on a pump block, which comprises a total of three identically designed pump chambers, in each of which a piston is immersed. In the FIGS. 1 . 3 . 4 and 5 one of the pump chambers 20 is shown, in which a piston 22 protrudes. Each pumping chamber 20 is associated with a suction valve 24 and a pressure valve 26. Liquid can be sucked in from the suction inlet 14 into the pumping space 20 via the suction valve 24, and the liquid pressurized in the pumping space 20 can escape from the pumping space 20 via the pressure valve 26.

The suction valves 24 each include a Saugventilschließkörper 28 which is sealingly engageable with a Saugventilsitz 30. The Saugventilsitz 30 surrounds a Saugventildurchlass 32. About the Saugventildurchlass 32 of the pump chamber 20 is in fluid communication with a Saugventilkammer 34, which on the pump head 12 facing side of the pump block 18 in the Pump block 18 is formed. At an axial distance from the suction valve 32, a holding arm 36 protrudes into the suction valve chamber 34, which extends approximately to the middle of the suction valve chamber 34 and aligned with the suction valve 32 has a passage opening 38 aligned.

The Saugventilschließkörper 28 is designed mushroom-shaped. It comprises a valve disk 40 protruding into the pump chamber 20, to which a valve stem 42 integrally connects, which passes through the suction valve passage 32 and dips into the suction valve chamber 34. The valve stem 42 passes through the passage opening 38 of the holding arm 36 and carries at its free end a spring holder 44 which is pressed onto the valve stem 42. Between the spring holder 44 and the holding arm 36, a Saugventilschließfeder 46 is clamped. The Saugventilschließfeder 46 is formed as a helical spring and surrounds the valve stem 42 in the region between the support arm 36 and the spring holder 44. Under the action of Saugventilschließfeder 46, the valve plate 40 of the Saugventilschließkörpers 28 is pressed against the Saugventilsitz 30.

The pressure valve 26 has a pressure valve closing body 48, which is pressed by a pressure valve closing spring 50 against a pressure valve seat 52. The pressure valve 26 is arranged in a pressure valve chamber 54. Each pumping chamber 20 of the piston pump 10 is associated with a suction valve chamber 34 and a pressure valve chamber 54, wherein all the pressure valve chambers 54 of the piston pump 10 merge into a common central chamber 56, which is formed by the pump block 18 and the pump head 12. In the central chamber 56, a central insert member 58 is inserted, which is surrounded by sealing rings and having a central passage 60 which is closed by a central closing body 62. The closing body 62, in combination with the central insert part, forms a central non-return valve, which is adjoined coaxially with a pump longitudinal axis 64 by a pressure line 66, via which the central chamber 56 is in flow communication with the pressure outlet 16.

The pump head 12 is mounted in the axial direction on the pump block 18 with the interposition of an elastically deformable element. In the illustrated embodiment, the elastically deformable element is designed as a sealing ring 68. The sealing ring 68 surrounds a collar-shaped edge 70 of the pump block 18. This is in particular from FIG. 2 clear. The edge 70 has the shape of an equilateral triangle with rounded corner areas. Based on a plan view of the pump block 18, the suction valves 24 are each arranged in a corner region of the edge 70. This is especially true FIG. 2 clear. The edge 70 surrounds a cylindrical inner wall 72 which defines the central chamber 56 in the region of the pump block 18. The pressure valves 26 are arranged in a plan view of the pump block 18 within the inner wall 72. This too will be out FIG. 2 clear.

As already mentioned, each pump chamber 20 is assigned a suction valve 24 with a suction valve seat 30 and a pressure valve 26 with a pressure valve seat 52. As in particular from FIG. 2 becomes clear, the respective pressure valve seat 52 is arranged relative to the pump longitudinal axis 64 offset both in the radial direction and in the circumferential direction of the piston pump 10 to the suction valve seat 30. The radial distance of the pressure valve seat 52 to the pump longitudinal axis 64 is less than the radial distance which the Saugventilsitz 30 occupies to the pump longitudinal axis 64, and in the circumferential direction of the piston pump 10, the pressure valve seat is offset in the illustrated embodiment by an angle α of about 25 ° to Saugventilsitz 30 ,

The piston pump 10 has a total of three Saugventilsitze 30 and three pressure valve seats 52, wherein the Saugventilsitze 30 as well as the pressure valve seats 52 define an imaginary equilateral triangle. The centers of the imaginary triangles are arranged on the pump longitudinal axis 64, the imaginary triangle of the pressure valve seats 52 but rotated by the angle α of 25 ° with respect to the imaginary triangle of Saugventilsitze 30 about the pump axis 64.

On the pump block 18 is connected in the axial direction with respect to the pump longitudinal axis 64 made of a plastic material support plate 74 with three cylindrical, aligned in each case to a piston longitudinal axis 76 support sleeves 78. The support sleeves 78 are each welded to an annular wall 80 of the pump block 18, which dips into the respective support sleeve 78 and surrounds a sealing ring 82 which rests sealingly with a sealing lip on the piston 22.

The support plate 74 is supported in the axial direction on a guide plate 84. The guide plate 84 has three cylindrical guide sleeves, wherein in FIG. 1 a guide sleeve 86 can be seen. The guide sleeves 86 form guide elements for the pistons 22 and are aligned coaxially with the respective piston longitudinal axis 76. The guide plate 84 forms a convex lid which rests on a swash plate housing 88 in which a swash plate 90 is rotatably mounted about the pump longitudinal axis 64. Each piston 22 is pressed by a return spring 92 against the swash plate 90. This makes it possible, by means of a rotary movement of the swash plate 90, to move the pistons 22 back and forth in the axial direction with respect to the pump longitudinal axis 64, so that the volumes of the pump chambers 20 are changed periodically. The drive of the swash plate 90 is carried out in a conventional manner by means of a known per se and therefore not shown in the drawing drive motor, such as an electric motor, via an in FIG. 1 only schematically illustrated gear 94 is coupled to the swash plate 90.

If the piston 22 moves backwards in the direction away from the pump head 12, liquid is sucked from the suction inlet 14 via the suction valve chamber 34 and the suction valve passage 32 into the pumping space 20, the suction valve closing body 28 lifting off the suction valve seat 30 against the action of the suction valve closing spring 46 and the suction valve passage 32 releases. The liquid can in this case flow past the suction valve closing spring 46 laterally within the suction valve chamber 34 and is therefore subject to only small flow losses in the suction valve chamber 34.

If the piston 22 then moves forward in the direction of the pump head 12, the suction valve closing body 28 moves into its closed position, in which it bears in a sealing manner on the suction valve seat 30, as shown in FIGS Figures 3 . 4 and 5 is shown. The liquid is then pressurized in the pump chamber 20 until the pressure valve closing body 48 lifts against the closing force of the pressure valve closing spring 50 from the pressure valve seat 52 and thus releases the flow connection between the pump chamber 20 and the central chamber 56. The pressure valve closing spring 50 is supported on the central insert part 58, whose passage 60 is released from the central closing body 62, so that the pressurized liquid can flow via the pressure line 66 to the pressure outlet 16.

The liquid can be placed in the pump chamber 20 under a pressure of over 100 bar. Despite a relatively low material thickness of the pump block 18 made of a plastic material can withstand the high pressures of the liquid. For this purpose, the pressure valve seats 52, as already explained above, arranged offset in the radial direction and in the circumferential direction with respect to the pump longitudinal axis 64 to the Saugventilsitzen 30. The piston pump 10 is therefore characterized by a high mechanical strength and a relatively low material thickness.

Claims (10)

1. Piston pump for a high-pressure cleaning appliance, comprising a plurality of pump chambers (20), into each of which one piston (22) which is movable back and forth plunges, and which are each in flow connection via a suction valve (24) with a suction inlet (14) and via a pressure valve (26) with a pressure outlet (16), the suction valve (24) comprising a suction valve closing member (28) which is sealingly positionable on a suction valve seat (30), and the pressure valve (26) comprising a pressure valve closing member (48) which is sealingly positionable on a pressure valve seat (52), the pressure valve seat (52) and the suction valve seat (30) being at different radial distances from a longitudinal pump axis (64), characterized in that the pressure valve seat (52) is arranged, in relation to the longitudinal pump axis (64), offset from the suction valve seat (30) in the circumferential direction of the piston pump (10).
2. Piston pump in accordance with claim 1, characterized in that the pressure valve seat (52) is arranged, in relation to the longitudinal pump axis (64), offset at an angle of 10° to 40° from the suction valve seat (30).
3. Piston pump in accordance with claim 1 or 2, characterized in that the pressure valve seat (52) is arranged, in relation to the longitudinal pump axis (64), at the same level as the suction valve seat (30) in the axial direction.
4. Piston pump in accordance with any one of the preceding claims, characterized in that the piston pump (10) comprises three suction valve seats (30) arranged so as to be uniformly distributed about the longitudinal pump axis (64) and three pressure valve seats (52) arranged so as to be uniformly distributed about the longitudinal pump axis (64).
5. Piston pump in accordance with any one of the preceding claims, characterized in that the piston pump (10) comprises a pump block (18) and a pump head (12), the pump head (12) comprising the suction inlet (14) and the pressure outlet (16), and the pump block (18) comprising the pump chambers (20) and accommodating the suction valves and the pressure valves (24, 26), and the pump head (12) being fitted on a triangular rim (70) of the pump block (18), the suction valves (24), in a plan view of the pump block (18), being arranged in the corner areas of the rim (70), and the pressure valves (26), in a plan view of the pump block (18), being surrounded by a cylindrical inside wall (72) within the rim (70).
6. Piston pump in accordance with any one of the preceding claims, characterized in that the suction valves (24) each comprise a suction valve passage (32) which is closable by the suction valve closing member (28), and a suction valve closing spring (46) which acts upon the suction valve closing member (28) with a spring force in the direction of the suction valve passage (32), the suction valve closing spring (46) being positioned at an axial distance from the suction valve passage (32).
7. Piston pump in accordance with claim 6, characterized in that the suction valve closing spring (46) is arranged in a suction valve chamber (34) which is in flow connection with a pump chamber (20) via the suction valve passage (32), a retaining arm (36), on which the suction valve closing spring (46) is supported, projecting into the suction valve chamber (34) at an axial distance from the suction valve passage (32).
8. Piston pump in accordance with claim 7, characterized in that the retaining arm (36) forms a guide for the suction valve closing member (28).
9. Piston pump in accordance with claim 7 or 8, characterized in that the retaining arm (36) comprises a through-opening (38) through which the suction valve closing member (28) passes.
10. Piston pump in accordance with claim 9, characterized in that the suction valve closing spring (46) is clamped on the side of the retaining arm (36) that faces away from the suction valve passage (32) between the retaining arm and the suction valve closing member (28).

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