Motor pump unit for a high-pressure cleaning appliance

Abstract

The invention relates to a motor pump unit (10) for a high-pressure cleaning appliance, comprising an electric motor (12), which has a cooling duct (28), a pump (14) having a pump inlet (22) and a pump outlet (26) , and a suction connection (53) for providing pressurized cleaning liquid, wherein the pump inlet (22) is fluidically connected to the suction connection (52) via the cooling duct (28). In order to develop the motor pump unit (10) in such a way that, even in the suction mode itself, when a powerful pump is used, a stable running behaviour of the pump can be ensured and the electric motor (12) can be effectively cooled, it is proposed according to the invention that the motor pump unit (10) has a distributor device (38) arranged upstream of the pump inlet (22) for dividing up the cleaning liquid, wherein one part of the cleaning liquid can be supplied to the pump inlet (22) via the cooling duct (28) and the remaining part of the cleaning liquid can be supplied to the pump inlet (22) bypassing the cooling duct (28).

Description

[0001] MOTOR PUMP UNIT FOR A HIGH-PRESSURE CLEANER

[0002] The invention relates to a motor pump unit for a high-pressure cleaning device, comprising an electric motor having a cooling channel, a pump having a pump inlet and a pump outlet, and a suction connection for providing cleaning fluid to be pressurized, wherein the suction connection is in flow connection with the pump inlet via the cooling channel.

[0003] Using such motor pump units, a cleaning fluid, preferably water, can be pressurized and then directed onto an object to be cleaned. For this purpose, a high-pressure hose, for example, can be connected to the pump outlet, which carries a spray gun or spray lance at its free end.

[0004] A supply line, such as a suction hose, can be connected to the suction connection. Cleaning fluid can be supplied to the pump via the supply line and the suction connection. The cleaning fluid can be under a pre-pressurized pressure of just a few bar. This can be the case, for example, if water from a public water supply network is used as the cleaning fluid. An operating mode of the motor pump unit in which cleaning fluid under pre-pressurized pressure is supplied to the pump is usually referred to as "pressure operation." However, the pump can also draw cleaning fluid from a reservoir, such as a collecting tank or a body of water. This type of operation is usually referred to as "suction operation."

[0005] The suction connection is connected to the pump inlet via the electric motor's cooling channel. This allows the electric motor to be cooled by first directing cleaning fluid through the cooling channel and only then flowing into the pump. However, the cooling channel, as well as any couplings and connecting lines through which the cleaning fluid is supplied to the cooling channel, create a significant flow resistance. In suction mode, the flow resistance can lead to a bottleneck in the supply of cleaning fluid and, consequently, to unstable pump operation when using a powerful pump, for example, one with a flow rate of more than 1,000 liters per hour.

[0006] The object of the present invention is therefore to further develop a motor pump unit of the type mentioned at the outset in such a way that stable running of the pump can be ensured even in suction operation, even when using a powerful pump, and the electric motor can be effectively cooled.

[0007] This object is achieved according to the invention in a motor pump unit of the generic type in that the motor pump unit has a distributor device arranged upstream of the pump inlet for dividing the cleaning liquid, wherein a part of the cleaning liquid can be supplied to the pump inlet via the cooling channel and the remaining part of the cleaning liquid can be supplied to the pump inlet bypassing the cooling channel.

[0008] In the motor pump unit according to the invention, the distribution device arranged upstream of the pump inlet divides the cleaning fluid into a first part, which is initially used to cool the electric motor and then flows into the pump, and a second part, which flows directly into the pump, bypassing the cooling channel. With the help of the first part, the electric motor can be effectively cooled, even if the cooling channel forms a considerable flow resistance, and with the help of the second part, even a very powerful pump can be supplied with sufficient fluid not only in pressure mode but also in suction mode, without the second part having to overcome considerable flow resistance.This ensures both effective cooling of the electric motor and stable running of the pump during suction operation, even if the pump has a high flow rate.

[0009] The provision of the distribution device also has the advantage that the start-up behavior of the pump can be improved, since air bubbles present at the beginning of operation can be eliminated within a very short time without all air bubbles having to be passed through the cooling channel first.

[0010] In a preferred embodiment of the invention, the distributor device provides a flow path via which the suction connection is in flow connection with the pump inlet, bypassing the cooling channel, wherein a throttle element is arranged in the flow path and upstream of the throttle element a branch line branches off from the flow path, which is in flow connection with a channel inlet of the cooling channel, and wherein downstream of the throttle element a return line opens into the flow path, which is in flow connection with a channel outlet of the cooling channel.A portion of the cleaning fluid can flow from the suction port directly to the pump inlet via the flow path, while the remaining portion of the cleaning fluid can branch off from the flow path upstream of the throttle element and first flow through the electric motor's cooling channel. The remaining portion can then be returned to the flow path via the return line downstream of the throttle element, allowing this portion of the cleaning fluid to also reach the pump inlet. The size of the two portions of cleaning fluid can be determined by the strength of the throttle element's throttling effect. The smaller the throttling effect, the more cleaning fluid flows through the flow path and reaches the pump inlet, bypassing the cooling channel.It is advantageous if the distributor device has a distributor housing into which the suction connection opens, wherein the flow path extends through the distributor housing and the throttle element is arranged in the distributor housing, wherein the distributor housing upstream of the throttle element has a liquid outlet which is in flow connection with the channel inlet of the cooling channel via the branch line, and wherein the distributor housing downstream of the throttle element has a liquid inlet, wherein the channel outlet of the cooling channel is in flow connection with the liquid inlet via the return line, and wherein the distributor housing downstream of the throttle element has a collecting outlet which is in flow connection with the pump inlet. The provision of the distributor housing enables a very compact design of the distributor device.The flow path, via which the suction port is in flow connection with the pump inlet, bypassing the cooling channel, extends through the distributor housing. The suction port opens into the distributor housing, allowing the cleaning fluid to flow into the distributor housing via the suction port. The throttle element is arranged in the flow path within the distributor housing. Upstream of the throttle element, the distributor housing has a fluid outlet to which the branch line is connected. Via the fluid outlet and the branch line, a first portion of the cleaning fluid can reach the cooling channel of the electric motor, flow through it, and then return to the distributor housing via the channel outlet of the cooling channel, the return line, and the fluid inlet downstream of the throttle element.The remaining part of the cleaning fluid can flow through the throttle element within the distributor housing and then, together with the first part of the cleaning fluid, reach the pump inlet via the collecting outlet of the distributor housing.

[0011] It is advantageous if the distributor housing has an inlet chamber and an outlet chamber, between which a partition wall with a through-opening forming the throttle element is arranged, wherein the suction port opens into the inlet chamber and the inlet chamber has the liquid outlet, and wherein the outlet chamber has the liquid inlet and the collecting outlet. In such a configuration of the distributor housing, the throttle element is designed in the form of a through-opening of a partition wall, which is arranged between an inlet chamber and an outlet chamber of the distributor housing. Cleaning fluid can flow into the inlet chamber via the suction port.Part of the cleaning fluid can flow from the inlet chamber through the fluid outlet and the branch line to the cooling channel, while the remaining part of the cleaning fluid can flow from the inlet chamber through the through-opening of the partition wall to the outlet chamber. The outlet chamber also collects the portion of the cleaning fluid used to cool the electric motor via the return line and the fluid inlet, allowing the entire cleaning fluid to then flow to the pump inlet via the outlet chamber's collecting outlet.

[0012] It is advantageous if the collector outlet can be detachably connected to the pump inlet. This facilitates the installation of the motor pump unit and any maintenance work.

[0013] In an advantageous embodiment of the invention, the outlet chamber forms an outlet nozzle, the free end of which forms the collecting outlet and which, with the interposition of a sealing element, can be releasably connected to the pump inlet. This enables a particularly compact design of the motor pump unit, eliminating the need for a connecting line between the collecting outlet and the pump inlet.

[0014] It is particularly advantageous if a filter device is arranged in the inlet chamber upstream of the fluid outlet and the throttle element. The filter device can be used to filter the cleaning fluid before it reaches the cooling jacket of the electric motor and the pump inlet. It is advantageous if the inlet chamber has a mounting opening, which can be closed by a housing cover, for inserting the filter device into the inlet chamber. The mounting opening provides access to the inlet chamber. The filter device can be inserted into the inlet chamber via the mounting opening and removed from the inlet chamber as needed, for example, for maintenance work.

[0015] The suction port is conveniently located on the housing cover. This allows for a simple design that allows the suction port and the housing cover to be separated from the inlet chamber if necessary.

[0016] In an advantageous embodiment of the invention, the suction connection is formed by a suction nozzle which passes through the housing cover.

[0017] In an advantageous embodiment of the invention, the filter device has a filter carrier on which a filter member for filtering the cleaning liquid is held, wherein the filter carrier rests liquid-tight on the suction nozzle with the interposition of a first sealing element and liquid-tight on a sealing surface of the inlet chamber with the interposition of a second sealing element.

[0018] The design of the throttle element in the form of a through-hole in the partition wall of the distributor housing has the advantage that the throttling effect of the throttle element can be easily specified by the size of the through-hole. The larger the through-hole, the lower the throttling effect and the greater the proportion of cleaning fluid that can be supplied to the pump inlet, bypassing the electric motor's cooling channel.

[0019] Advantageously, the diameter of the passage opening of the partition wall is 30% to 70% of the inner diameter of the fluid outlet and the fluid inlet, in particular 40% to 60%, preferably 50%. It is advantageous if the distributor housing can be detachably connected to the pump. This facilitates the assembly of the distributor housing to the pump. For example, it can be provided that the distributor housing can be screwed to the pump.

[0020] In a preferred embodiment of the invention, the pump has a cylinder head, and the distributor housing is arranged below the cylinder head in a horizontal operating position of the motor pump unit. This enables a particularly compact design of the motor pump unit.

[0021] It is advantageous if the longitudinal axis of the distributor housing is aligned parallel to the longitudinal axis of the cylinder head.

[0022] The following description of an advantageous embodiment of the invention serves to explain it in more detail in conjunction with the drawings. They show:

[0023] Figure 1: a perspective view of a motor pump unit;

[0024] Figure 2: a perspective view of a distributor housing of the motor pump unit from Figure 1;

[0025] Figure 3: a longitudinal sectional view of the distributor housing;

[0026] Figure 4: a side view of the motor pump unit cut open in the area of ​​the distributor housing.

[0027] The drawing schematically shows an advantageous embodiment of a motor pump unit according to the invention for a high-pressure cleaning device. The motor pump unit is designated overall by the reference numeral 10 and has an electric motor 12 and a pump 14 driven by the electric motor 12. In the illustrated embodiment, the pump 14 is designed as a crankshaft pump having a pump block 16 and a cylinder head 18 laterally adjacent to the pump block 16. Such pumps are known to those skilled in the art, for example, from WO 2016 / 015763 A1. The pump block 16 accommodates, in a known manner, a crank drive with a crankshaft, with the aid of which pistons known to those skilled in the art and therefore not shown in the drawing can be driven in a reciprocating movement. The cylinder head 18 has a pump inlet 22 on an underside 20 and a pump outlet 26 on an end face 24.Pressurized cleaning fluid can be supplied to the pump 14 via the pump inlet 22, and the pressurized cleaning fluid from the pump 14 can then be discharged via the pump outlet 26. A high-pressure line can be connected to the pump outlet 26 in a known manner, which line can carry, for example, a spray gun or a spray lance at its free end.

[0028] The electric motor 12 has a cooling channel 28, which in the illustrated embodiment is designed as a cooling coil 30 that circumferentially surrounds a motor housing 32 of the electric motor 12. Alternatively, the cooling channel 28 could also be designed, for example, as a cooling jacket that circumferentially surrounds the motor housing 32. 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.

[0029] The motor pump unit 10 also has a distributor device 38 with a distributor housing 40, the interior of which is divided by a partition wall 42 into an inlet chamber 44 and an outlet chamber 46. This is clearly shown in Figures 3 and 4.

[0030] The inlet chamber 44 accommodates a filter device 48, which is held on a suction nozzle 50 projecting into the inlet chamber 44 and forming a suction connection 52 at its end protruding from the inlet chamber 44. A suction line known per se to those skilled in the art, for example, a suction hose, can be connected to the suction connection 52.

[0031] The inlet chamber 44 has, on its side opposite the partition wall 42, a mounting opening 54 that can be closed by 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 opening 60 through which the suction nozzle 50 passes.

[0032] The filter device 48 has a filter carrier 62 which carries a filter member 64, for example a sieve member, and, with the interposition of a first sealing element in the form of a first sealing ring 66, lies in a liquid-tight manner on the end of the suction nozzle 50 projecting into the inlet chamber 44 and, with the interposition of a second sealing element in the form of a second sealing ring 68, lies in a liquid-tight manner on a sealing surface 70 of the inlet chamber 44 arranged adjacent to the mounting opening 54.

[0033] In the area 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.

[0034] 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.

[0035] A 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 a return line 82.

[0036] The outlet chamber 46 forms an outlet connection 84 facing the pump inlet 22, which forms a collecting outlet 86 at its free end and is connected to the pump inlet 22 in a fluid-tight manner with the interposition of a third sealing element in the form of a third sealing ring 87. On its outer side, the distributor housing 40 has two screw bosses 88, 90, each of which can be penetrated by a connecting screw 92, with the aid 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 is visible in the drawing.

[0037] With respect to the horizontal operating position of the motor pump unit 10 shown in Figures 1 and 4, the distributor housing 40 is arranged below the cylinder head 18, with a longitudinal axis 94 of the distributor housing 40 aligned parallel to a longitudinal axis 96 of the cylinder head 18. This gives the motor pump unit 10 a particularly compact design.

[0038] Pressurized cleaning fluid, preferably water, can be sucked in by means of the pump 14 during suction operation of the motor pump unit. The sucked-in cleaning fluid first reaches the inlet chamber 44 via the suction port 50, where it is filtered by the filter device 48. Within the inlet chamber 44, the sucked-in cleaning fluid is divided, with a portion of the fluid being able to reach the channel inlet 34 of the cooling channel 28 via the fluid outlet 72 and the branch line 74, so that it can then flow through the cooling channel 28 and then flow into the outlet chamber 46 via the channel outlet 36 and the return line 82. This portion of the cleaning fluid is thus used to cool the electric motor 12.

[0039] The remaining part of the 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. Starting from the outlet chamber 46, the entire sucked-in cleaning fluid can then flow via the collecting outlet 86 to the pump inlet 22 in order to be pressurized by the pump 14. The distributor device 38 thus forms a flow path by means of the distributor housing 40, which extends from the suction connection 52 via the inlet chamber 44, the throttle element 78, the outlet chamber 46 and the collecting outlet 86 to the pump inlet 22, bypassing the cooling channel 28. Upstream of the throttle element 78, the branch line 74 branches off from this flow path and carries a portion of the sucked-in cleaning fluid to the cooling channel 28, from which the cleaning fluid then flows back into the flow path via the return line 82 downstream of the throttle element 78.

[0040] The proportion of cleaning fluid used to cool the electric motor 12 can be specified by selecting the diameter of the through-opening 76. The larger the diameter of the through-opening 76, the smaller the proportion of cleaning fluid used to cool the electric motor 12.

[0041] To ensure effective cooling of the electric motor with stable running behavior, even for a very powerful pump, even in suction mode 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. A diameter of the through-opening 76 that is 40% to 60% of the inner diameter of the liquid outlet 72 and the liquid inlet 80 has proven particularly advantageous. In particular, it can be provided that the diameter of the through-opening 76 is half the size of the inner diameter of the liquid outlet 72 and the liquid inlet 80.

Claims

PATENT CLAIMS Motor pump unit 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 cleaning fluid to be pressurized, 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 distributor device (38) arranged upstream of the pump inlet (22) for dividing the cleaning fluid, wherein a part of the cleaning fluid can be fed to the pump inlet (22) via the cooling channel (28) and the remaining part of the cleaning fluid can be fed to the pump inlet (22) bypassing the cooling channel (28).Motor pump unit according to claim 1, characterized in that the distributor 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 throttle element (78) is arranged in the flow path and upstream of the throttle element (78) a branch line (74) branches off from the flow path, which is in flow connection with a channel inlet (34) of the cooling channel (28), and wherein downstream of the throttle element (78) a return line (82) opens into the flow path, which is in flow connection with a channel outlet (36) of the cooling channel (28). Motor pump unit according to claim 2, characterized in that the distributor device (38) has a distributor housing (40) into which the suction connection (52) opens, wherein the flow path opens. extends through the distributor housing (40) and the throttle element (78) is arranged in the distributor housing (40), wherein the distributor housing (40) upstream of the throttle element (78) has a liquid outlet (72) which is in flow connection with the channel inlet (34) of the cooling channel (28) via the branch line (74), and wherein the distributor housing (40) downstream of the throttle element (78) has a liquid inlet (80), 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) downstream of the throttle element (78) has a collecting outlet (86) which is in flow connection with the pump inlet (22).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) with a through-opening (76) forming the throttle element (78) is arranged, 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). Motor pump unit according to claim 4, characterized in that the collecting outlet (86) is detachably connectable to the pump inlet (22). Motor pump unit according to claim 5, characterized in that the outlet chamber (46) forms an outlet nozzle (84), the free end of which forms the collecting outlet (86) and which can be detachably connected to the pump inlet (22) with the interposition of a sealing element (87). 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). Motor pump unit according to claim 7, characterized in that the inlet chamber (44) has a mounting opening (54) that can be closed by a housing cover (56) for inserting the filter device (48) into the inlet chamber (44). Motor pump unit according to claim 8, characterized in that the suction connection (52) is arranged on the housing cover (56). Motor pump unit according to claim 9, characterized in that the suction connection (52) is formed by a suction nozzle (50) that passes through the housing cover (56).Motor pump unit according to claim 10, characterized in that the filter device (48) has a filter carrier (62) on which a filter member (64) is held, wherein the filter carrier (62) rests in a liquid-tight manner on the suction nozzle (50) with the interposition of a first sealing element (66) and in a liquid-tight manner on a sealing surface (70) of the inlet chamber (44) with the interposition of a second sealing element (68). Motor pump unit according to 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 diameters of the liquid outlet (72) and the liquid inlet (80). Motor pump unit according to one of claims 3 to 12, characterized in that the distributor housing (40) is detachably connectable to the pump (14). Motor pump unit according to 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 position of use of the motor pump unit (10). Motor pump unit according to claim 14, characterized in that a longitudinal axis (94) of the distributor housing (40) is aligned parallel to a longitudinal axis (96) of the cylinder head (18).

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