Motor pump unit for high-pressure cleaning device

Abstract

The invention relates to a motor pump unit (10) for a high-pressure cleaning device, comprising an electric motor (12) having a cooling channel (28), a pump (14) having a pump inlet (22) and a pump outlet (26), and a suction connection (52) for providing a cleaning liquid to be pressurized, the pump inlet (22) being in flow connection with the suction connection (52) via the cooling channel (28). In order to improve the motor pump unit (10) in such a way that a stable operating behavior of the pump can be ensured and the electric motor (12) can be effectively cooled during the suction operation itself when the power-efficient pump is used, according to the invention the motor pump unit (10) has a distribution device (38) arranged upstream of the pump inlet (22) for dividing the cleaning liquid, a part of the cleaning liquid can be fed to the pump inlet (22) via the cooling channel (28) and the remaining part of the cleaning liquid can be fed to the pump inlet (22) bypassing the cooling channel (28).

Description

Technical Field

[0001] The invention relates to a motor pump unit for a high-pressure cleaning device, comprising an electric motor with a cooling channel, a pump with a pump inlet and a pump outlet, and a suction connection for providing a cleaning liquid to be put under pressure, wherein the suction connection is in flow connection with the pump inlet via the cooling channel. Background Art

[0002] With this motor pump unit, cleaning fluid, preferably water, can be placed under pressure and then directed at the object to be cleaned. For this reason, for example, a high-pressure hose is connected to the pump outlet, which carries a spray gun or a nozzle at its free end.

[0003] A supply line, for example a suction hose, can be connected to the suction connection. The pump can be supplied with cleaning liquid via the supply line and the suction connection. The cleaning liquid can already be under a pre-pressure of several bars. This can be the case, for example, when water from a public water supply network is used as cleaning liquid. An operating mode of the motor pump unit, in which cleaning liquid under pre-pressure is supplied to the pump, is generally referred to as "pressure operation". However, the pump can also suck the cleaning liquid from a reservoir, for example from a collecting container or a body of water. This operating mode is generally referred to as "suction operation".

[0004] The suction connection is in flow connection with the pump inlet via the cooling channel of the electric motor. This allows the electric motor to be cooled in such a way that the cleaning liquid is first guided through the cooling channel and then flows into the pump. However, the cooling channel and any joints and connecting lines, via which the cleaning liquid is supplied to the cooling channel, also create a significant flow resistance. In suction operation, the flow resistance leads to insufficient supply of cleaning liquid and thus to unstable operating characteristics of the pump when using powerful pumps, for example when using pumps with a delivery rate of more than 1000 liters / hour. Summary of the invention

[0005] The object of the present invention is therefore to improve a motor pump unit of the type mentioned in the introduction in such a way that stable operating characteristics of the pump are ensured even when using powerful pumps during the suction operation itself and that the electric motor can be cooled very effectively.

[0006] According to the invention, this object is achieved in a motor pump unit of this type in that the motor pump unit has a distribution device arranged upstream of the pump inlet for dividing the cleaning liquid, wherein a portion of the cleaning liquid can be supplied to the pump inlet via a cooling channel and the remaining portion of the cleaning liquid can be supplied to the pump inlet bypassing the cooling channel.

[0007] In the motor pump unit according to the invention, the cleaning liquid is divided into a first part and a second part by means of a distributor arranged upstream of the pump inlet, the first part being used first to cool the electric motor and then flowing into the pump, and the second part flowing directly into the pump, bypassing the cooling channel. Even if the cooling channel forms a significant flow resistance, the electric motor can be cooled very effectively by means of the first part, and even a very powerful pump can be supplied with sufficient liquid both in pressure operation and in suction operation by means of the second part, without having to overcome a significant flow resistance by the second part. Thus, even in suction operation, very effective cooling of the electric motor and stable operating characteristics of the pump can be ensured, even if the pump has a high delivery rate.

[0008] The provision of a distributor device has the advantage, among other things, that the starting behavior of the pump can be improved, since gas bubbles present at the start of operation can be eliminated in a very short time without having to first conduct all of the gas bubbles through the cooling channel.

[0009] In a preferred design of the present invention, the distribution device provides a flow path, and the suction connection is in flow connection with the pump inlet via the flow path bypassing the cooling channel, wherein a throttling element is arranged in the flow path and a branch line is branched from the flow path upstream of the throttling element, and the branch line is in flow connection with the channel inlet of the cooling channel, and wherein, downstream of the throttling element, a return line is introduced into the flow path, and the return line is in flow connection with the channel outlet of the cooling channel. A part of the cleaning liquid can flow directly from the suction connection to the pump inlet through the flow path, and the remaining part of the cleaning liquid can be branched from the flow path upstream of the throttling element and first flow through the cooling channel of the electric motor, so as to be subsequently led back to the flow path downstream of the throttling element through the return line, so that this part of the cleaning liquid can also reach the pump inlet. The amount of the two parts of the cleaning liquid can be predetermined by the strength of the throttling effect of the throttling element. The smaller the throttling effect, the more cleaning liquid flows through the flow path and reaches the pump inlet bypassing the cooling channel.

[0010] Advantageously, the distribution device has a distributor housing, and the suction connection leads into the distributor housing, wherein the flow path extends through the distributor housing and the throttling element is arranged in the distributor housing, wherein the distributor housing has a liquid outlet upstream of the throttling element, and the liquid outlet is in flow connection with the channel inlet of the cooling channel via a branch line, and wherein the distributor housing has a liquid inlet downstream of the throttling element, wherein the channel outlet of the cooling channel is in flow connection with the liquid inlet via a return line, and wherein the distributor housing has a collecting outlet downstream of the throttling element, and the collecting outlet is in flow connection with the pump inlet. Providing a distributor housing enables a very compact design of the distribution device to be realized. The flow path extends through the distributor housing, and the suction connection is in flow connection with the pump inlet via the distributor housing bypassing the cooling channel. The suction connection leads into the distributor housing, so that the cleaning liquid can flow into the distributor housing via the suction connection. In the distributor housing, the throttling element is arranged in the flow path. Upstream of the throttling element, the distributor housing has a liquid outlet, and the branch line is connected to the liquid outlet. The first part of the cleaning liquid can reach the cooling channel of the electric motor via the liquid outlet and the branch line, flow through the cooling channel and then enter the distributor housing again downstream of the throttle element via the channel outlet of the cooling channel, the return line and the liquid inlet. The remaining part of the cleaning liquid can flow through the throttle element in the distributor housing and then reach the pump inlet together with the first part of the cleaning liquid via the collection outlet of the distributor housing.

[0011] Advantageously, the distributor housing has an input chamber and an output chamber, between which a partition wall is arranged, the partition wall having a through opening constituting a throttling element, wherein the suction connection leads into the input chamber and the input chamber has a liquid outlet, and wherein the output chamber has a liquid inlet and a collecting outlet. In this design of the distributor housing, the throttling element is designed in the form of a through opening of the partition wall, which is arranged between the input chamber and the output chamber of the distributor housing. Cleaning liquid can flow into the input chamber via the suction connection. A portion of the cleaning liquid can flow from the input chamber via the liquid outlet and the branch line to the cooling channel and the remaining portion of the cleaning liquid can flow from the input chamber via the through opening of the partition wall to the output chamber. Via the return line and the liquid inlet, the output chamber also accommodates that portion of the cleaning liquid used to cool the electric motor, so that all the cleaning liquid can then reach the pump inlet via the collecting outlet of the output chamber.

[0012] Advantageously, the collecting outlet can be connected to the pump inlet in a detachable manner. This facilitates the assembly of the motor pump unit and also facilitates possible maintenance work.

[0013] In an advantageous embodiment of the invention, the outlet chamber forms an outlet connection, the free end of which forms the collecting outlet and which can be detachably connected to the pump inlet with a sealing element interposed therebetween. This allows a particularly compact embodiment of the motor pump unit, in which case a connecting line between the collecting outlet and the pump inlet is omitted.

[0014] It is particularly advantageous if a filter device is arranged in the inlet chamber upstream of the liquid outlet and the throttle element. The filter device can be used to filter the cleaning liquid before it can reach the cooling jacket of the electric motor and the pump inlet.

[0015] Advantageously, the inlet chamber has an assembly opening that can be closed by the housing cover for inserting the filter device into the inlet chamber. The assembly opening forms access to the inlet chamber. The filter device can be inserted into the inlet chamber through the assembly opening and removed from the inlet chamber when necessary, for example for maintenance work.

[0016] The suction connection is advantageously arranged on the housing cover. This makes it possible to separate the suction connection together with the housing cover from the inlet chamber in a structurally simple manner when necessary.

[0017] In an advantageous embodiment of the invention, the suction connection is formed by a suction pipe which passes through the housing cover.

[0018] In an advantageous embodiment of the invention, the filter device comprises a filter carrier on which a filter element for filtering a cleaning fluid is held, wherein the filter carrier abuts against the suction nozzle in a liquid-tight manner with a first sealing element interposed therein and abuts against a sealing surface of an inlet chamber in a liquid-tight manner with a second sealing element interposed therein.

[0019] The embodiment of the throttling element in the form of a through-opening of the partition wall of the distributor housing has the advantage that the throttling effect of the throttling element can be predetermined in a simple manner by the size of the through-opening. The larger the through-opening, the smaller the throttling effect and the greater the proportion of cleaning fluid that can be fed to the pump inlet bypassing the cooling channel of the electric motor.

[0020] The diameter of the through-opening of the partition wall is advantageously 30% to 70%, in particular 40% to 60%, preferably 50%, of the inner diameter of the liquid outlet and the liquid inlet.

[0021] Advantageously, the distributor housing can be connected to the pump in a detachable manner. This facilitates the installation of the distributor housing at the pump. Thus, it can be provided, for example, that the distributor housing can be screwed to the pump.

[0022] In a preferred embodiment of the invention, the pump has a cylinder cover and the distributor housing is arranged below the cylinder cover in the horizontal operating position of the motor pump unit. This enables a particularly compact embodiment of the motor pump unit.

[0023] Advantageously, the longitudinal axis of the distributor housing is oriented parallel to the longitudinal axis of the cylinder head. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following description of advantageous embodiments of the present invention is intended to be explained in more detail in conjunction with the accompanying drawings. In the drawings:

[0025] Figure 1 A perspective view showing a motor pump unit;

[0026] Figure 2 Show Figure 1 A perspective view of a distributor housing of a motor pump unit;

[0027] Figure 3 A longitudinal sectional view of a dispenser housing is shown;

[0028] Figure 4 The motor pump unit is shown in a disassembled side view in the region of the distributor housing. DETAILED DESCRIPTION

[0029] In the figure, a favorable embodiment of the motor pump unit according to the present invention for a high-pressure cleaning device is schematically shown. The motor pump unit is generally marked with reference numeral 10 and has an electric motor 12 and a pump 14, which is driven by the electric motor 12. In the illustrated embodiment, the pump 14 is designed as a crankshaft pump, which has a pump body 16 and a cylinder head 18 that is laterally attached to the pump body 16. Such a pump is known to those skilled in the art, for example, from WO 2016 / 015763 A1. The pump body 16 accommodates a crankshaft transmission mechanism with a crankshaft in a known manner, by means of which a piston known to those skilled in the art and therefore not shown in the drawings can be driven to reciprocating motion. The cylinder head 18 has a pump inlet 22 at the bottom 20 and a pump outlet 26 at the end side 24. The cleaning liquid to be placed under pressure can be supplied to the pump 14 via the pump inlet 22, and the cleaning liquid placed under pressure by the pump 14 can be discharged immediately via the pump outlet 26. A high-pressure line can be connected to the pump outlet 26 in a known manner, and at its free end the high-pressure line can carry, for example, a spray gun or a nozzle.

[0030] The electric motor 12 has a cooling channel 28, which is designed as a cooling coil 30 in the embodiment shown, and surrounds the motor housing 32 of the electric motor 12 in the circumferential direction. Alternatively, the cooling channel 28 can also be designed as a cooling jacket that surrounds the motor housing 32 in the circumferential direction. Such cooling coils and cooling jackets are known to those skilled in the art, for example, from DE 81 11 792 U1 and DE 38 17 641 A1. The cooling channel 28 has a channel inlet 34 and a channel outlet 36.

[0031] The motor pump unit 10 further comprises a distributor device 38 with a distributor housing 40, the interior of which is divided into an inlet chamber 44 and an outlet chamber 46 by means of a partition wall 42. Figure 3 and 4 Indicated in.

[0032] The inlet chamber 44 accommodates a filter device 48, which is held on a suction pipe 50 that projects into the inlet chamber 44 and forms a suction connection 52 at its end that projects from the inlet chamber 44. A suction line known per se to a person skilled in the art, for example a suction hose, can be connected to the suction connection 52.

[0033] The inlet chamber 44 has, on its side opposite the partition wall 42, an assembly opening 54 which can be closed by means of a housing cover 56. The housing cover 56 is detachably connected to the distributor housing 40 via a screw connection 58 and has a central aperture 60 through which the intake nozzle 50 passes.

[0034] The filter device 48 has a filter carrier 62, which carries a filter element 64, for example a sieve element, and abuts in a liquid-tight manner on the end of the suction pipe 50 that extends into the inlet chamber 44 with a first sealing element in the form of a first sealing ring 66 interposed therein, and abuts in a liquid-tight manner on a sealing surface 70 of the inlet chamber 44 that is arranged adjacent to the assembly opening 54 with a second sealing element in the form of a second sealing ring 68 interposed therein.

[0035] In the region between the sealing surface 70 and the partition wall 42 , the inlet chamber 44 has a liquid outlet 72 which is in flow connection with the channel inlet 34 of the cooling channel 28 via a branch line 74 .

[0036] The partition wall 42 has a through-opening 76 which forms a throttle element 78 and via which the inlet chamber 44 is in flow connection with the outlet chamber 46 .

[0037] The liquid inlet 80 opens into the outlet chamber 46 . The outlet chamber 46 is in flow connection with the channel outlet 36 of the cooling channel 28 via the liquid inlet 80 and the return line 82 .

[0038] Facing the pump inlet 22 , the outlet chamber 46 forms an outlet connection piece 84 which forms a collecting outlet 86 at its free end and is connected to the pump inlet 22 in a fluid-tight manner with an interposed third sealing element in the form of a third sealing ring 87 .

[0039] The distributor housing 40 has two spiral domes 88, 90 on its outer side, which can each be penetrated by a connecting screw 92, by means of which the distributor housing 40 can be detachably connected to the cylinder head 18. Only one of the two identically designed connecting screws 92 can be seen in the figure.

[0040] Reference motor pump unit 10 in Figure 1 and 4 In the horizontal position of use shown in FIG, the distributor housing 40 is arranged below the cylinder head 18, wherein the longitudinal axis 94 of the distributor housing 40 is oriented parallel to the longitudinal axis 96 of the cylinder head 18. This gives the motor pump unit 10 a particularly compact design.

[0041] The cleaning liquid to be put under pressure, preferably water, can be sucked in during the suction operation of the motor pump unit by means of the pump 14. The sucked cleaning liquid first enters the inlet chamber 44 via the suction connection 50, wherein the cleaning liquid is filtered by means of the filter device 48. The sucked cleaning liquid is divided in the inlet chamber 44, wherein a part of the cleaning liquid can reach the channel inlet 34 of the cooling channel 28 via the liquid outlet 72 and the branch line 74, so that the cleaning liquid can then flow through the cooling channel 28, in order to then flow into the outlet chamber 46 via the channel outlet 36 and the return line 82. This part of the cleaning liquid is therefore used to cool the electric motor 12.

[0042] The remaining cleaning fluid flowing into the inlet chamber 44 flows directly into the outlet chamber 46 via the through-opening 76 forming the throttle element 78. From the outlet chamber 46, all the sucked cleaning fluid can flow via the collecting outlet 86 to the pump inlet 22 to be put under pressure by the pump 14.

[0043] The distributor device 38 thus forms a flow path with the distributor housing 40, which extends from the suction connection 52, bypassing the cooling channel 28, via the inlet chamber 44, the throttle element 78, the outlet chamber 46 and the collecting outlet 86 to the pump inlet 22. The branch line 74 branches off from this flow path upstream of the throttle element 78 and guides part of the sucked cleaning fluid to the cooling channel 28, from which the cleaning fluid then re-enters the flow path downstream of the throttle element 78 via the return line 82.

[0044] The proportion of the cleaning fluid used for cooling the electric motor 12 can be predetermined by selecting the diameter of the through-opening 76. The larger the diameter of the through-opening 76 is selected, the smaller the proportion of the cleaning fluid used for cooling the electric motor 12.

[0045] In order to ensure very effective cooling of the electric motor even with the stable operating characteristics of the very powerful pump itself during the suction operation of the motor pump unit 10, it is advantageous if the diameter of the through-opening is 30% to 70% of the diameter of the liquid outlet 72 and the liquid inlet 80. It has proven to be particularly advantageous if the diameter of the through-opening 76 is 40% to 60% of the inner diameter of the liquid outlet 72 and the liquid inlet 80. In particular, it can be provided that the diameter of the through-opening 76 is half as large as the diameter of the liquid outlet 72 and the liquid inlet 80.

Claims

1. A motor pump unit for a high-pressure cleaning device, comprising an electric motor (12) with a cooling channel (28), a pump (14) with a pump inlet (22) and a pump outlet (26), and a suction connection (52) for providing a cleaning liquid to be put under pressure, wherein: The suction connection (52) is in flow connection with the pump inlet (22) via the cooling channel (28), characterized in that the motor pump unit (10) has a distribution device (38) arranged upstream of the pump inlet (22) for dividing the cleaning liquid, wherein a portion of the cleaning liquid can be supplied to the pump inlet (22) via the cooling channel (28) and a remaining portion of the cleaning liquid can be supplied to the pump inlet (22) bypassing the cooling channel (28).

2. The motor pump unit according to claim 1, characterized in that The distribution device (38) provides a flow path, via which the suction connection (52) is in flow connection with the pump inlet (22) bypassing the cooling channel (28), wherein a throttling element (78) is arranged in the flow path and upstream of the throttling element (78), a branch line (74) branches off from the flow path, the branch line being in flow connection with the channel inlet (34) of the cooling channel (28), and wherein downstream of the throttling element (78), a return line (82) opens into the flow path, the return line being in flow connection with the channel outlet (36) of the cooling channel (28).

3. The motor pump unit according to claim 2, characterized in that The distributor device (38) comprises a distributor housing (40) into which the suction connection (52) opens, wherein the flow path extends through the distributor housing (40) and the throttling element (78) is arranged in the distributor housing (40), wherein the distributor housing (40) has a liquid outlet (72) upstream of the throttling element (78), the liquid outlet being in flow connection with a channel inlet (34) of the cooling channel (28) via the branch line (74), and wherein the distributor housing (40) has a liquid inlet (80) downstream of the throttling element (78), wherein the channel outlet (36) of the cooling channel (28) is in flow connection with the liquid inlet (80) via the return line (82), and wherein the distributor housing (40) has a collecting outlet (86) downstream of the throttling element (78), the collecting outlet being in flow connection with the pump inlet (22).

4. The motor pump unit according to claim 3, characterized in that The distributor housing (40) has an inlet chamber (44) and an outlet chamber (46), between which a partition wall (42) is arranged, the partition wall having a through opening (76) forming the throttling element (78), wherein the suction connection (52) opens into the inlet chamber (44) and the inlet chamber (44) has the liquid outlet (72), and wherein the outlet chamber (46) has the liquid inlet (80) and the collecting outlet (86).

5. The motor pump unit according to claim 4, characterized in that The collecting outlet (86) is detachably connectable to the pump inlet (22).

6. The motor pump unit according to claim 5, characterized in that The outlet chamber (46) forms an outlet connection piece (84), the free end of which forms the collecting outlet (86) and which can be detachably connected to the pump inlet (22) with a sealing element (87) interposed therebetween.

7. The motor pump unit according to claim 4, 5 or 6, characterized in that A filter device (48) is arranged in the inlet chamber (44) upstream of the liquid outlet (72) and the throttle element (78).

8. The motor pump unit according to claim 7, characterized in that The inlet chamber (44) has an installation opening (54) which can be closed by a housing cover (56) for inserting the filter device (48) into the inlet chamber (44).

9. The motor pump unit according to claim 8, characterized in that The suction connection (52) is arranged on the housing cover (56).

10. The motor pump unit according to claim 9, characterized in that The suction connection (52) is formed by a suction connection piece (50) which passes through the housing cover (56).

11. The motor pump unit according to claim 10, characterized in that The filter device (48) has a filter carrier (62) on which a filter element (64) is held, wherein the filter carrier (62) bears against the intake nozzle (50) in a liquid-tight manner with a first sealing element (66) interposed therebetween and bears against a sealing surface (70) of the inlet chamber (44) in a liquid-tight manner with a second sealing element (68) interposed therebetween.

12. The motor pump unit according to any one of claims 4 to 10, characterized in that The diameter of the through opening (76) of the partition wall (42) is 30% to 70% of the inner diameter of the liquid outlet (72) and the liquid inlet (80).

13. The motor pump unit according to any one of claims 3 to 12, characterized in that The distributor housing (40) is detachably connectable to the pump (14).

14. The motor pump unit according to any one of claims 3 to 13, characterized in that The pump (14) has a cylinder head (18), and the distributor housing (40) is arranged below the cylinder head (18) in a horizontal operating position of the motor pump unit (10).

15. The motor pump unit according to claim 14, characterized in that A longitudinal axis (94) of the distributor housing (40) is oriented parallel to a longitudinal axis (96) of the cylinder head (18).

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