CN110832200A - High pressure cleaning equipment - Google Patents

Abstract

The invention relates to a high-pressure cleaning appliance (10) having a pump (14) which has a suction line (24) and a pressure line (30), wherein a check valve (34) is arranged in the pressure line (30), and the pump has a relief valve (84) which releases a flow path through a relief line (74) as a function of pressure in order to let cleaning liquid flow out of the pressure line (30). The overflow valve (84) has a closing body (86) which rests in a liquid-tight manner against a valve seat (82) in a closed position, can be moved against a closing force of a closing spring (92) into an open position spaced apart from the valve seat (82), and is connected to a control piston (58) which is held in a movable manner in a control chamber (56) and can be charged with cleaning liquid under pressure. In order to reduce the size of the relief valve (84) without using an injector, the control piston (58) divides the control chamber (56) into a discharge pressure chamber (64) and a relief chamber (66). The outlet pressure chamber (64) is connected to a region of the pressure line (30) which is arranged downstream of the check valve (34) and has a first through-opening (96) which is penetrated by a piston rod (94) which is fastened to the control piston (58). The overflow chamber (66) is connected to a region of the pressure line (30) which is arranged upstream of the check valve (34) and has a second through-opening (80) which forms a valve seat (82). The through-openings (96, 80) are not equally large, and the control piston (58) can be loaded on its side facing the larger through-opening to close the closing force of the spring (92).

Description

High pressure cleaning equipment

technical field

The invention relates to a high-pressure cleaning device having a pump for delivering cleaning liquid, wherein the pump has a suction line and a pressure line, a non-return valve is arranged in the pressure line, and wherein the pump has an overflow valve, The overflow valve is dependent on the pressure of the cleaning liquid present in the pressure line to release the flow path through the overflow line in order to allow the cleaning liquid to flow out of the pressure line, wherein the overflow valve has a liquid-tight abutment in the closed position. A closing body on the valve seat, which can be moved against the closing force of the closing spring into an open position spaced from the valve seat, and which is displaceably held in the control chamber by means of the valve stem and can be loaded Connected with a control piston of cleaning liquid under pressure.

Background technique

With such a high-pressure cleaning device, a cleaning liquid, preferably water, can be brought under pressure and directed towards the surface to be cleaned. The high-pressure cleaning device has a pump, which can be driven by a motor, preferably an electric motor, and has at least one reciprocating piston, which sinks into the pump chamber. Preferably, the pump includes three reciprocating pistons, which are respectively sunk into the pump cavity. The cleaning liquid under pressure may be conveyed to the pump through a liquid delivery line, eg, a suction hose, and the cleaning liquid under pressure may be delivered by the pump through a liquid output line, eg, a high pressure hose, to the liquid output devices, such as spray guns or booms. The liquid output device has a valve that can be opened and closed by the user. Clean liquid under pressure can be delivered while the valve is open, and liquid delivery can be terminated by closing the valve.

The high-pressure cleaning device has an overflow valve which opens depending on the pressure present in the pressure line and releases the flow path so that cleaning liquid can flow out of the pressure line through the overflow line in order to reduce the pressure in the pressure line. If the valve of the liquid outlet means is closed, the pressure of the cleaning liquid in the pressure line is increased due to the continued activity of the pump. When a preset maximum value of the pressure is exceeded, the overflow valve releases the flow path so that cleaning liquid can flow out of the pressure line through the overflow line.

For example, it can be provided that the flow path extends from the pressure line through the overflow line to the suction line, so that when a preset maximum value of the pressure prevailing in the pressure line is exceeded, the overflow valve opens and the cleaning liquid can escape from the pressure line. The pressure line flows through the overflow line to the suction line. The pump can thus be cycled.

It can also be provided that the flow path extends from the pressure line through the overflow line to an outlet through which cleaning liquid can be discharged when a predetermined maximum value of the pressure prevailing in the pressure line is exceeded.

It can also be provided that the flow path extends from the pressure line to a collecting space which receives cleaning liquid from the pressure line when the pressure prevailing in the pressure line is exceeded.

It can be provided that the pump is switched off after opening the overflow valve.

The overflow valve has a closing body, which in the closed position bears against the valve seat in a liquid-tight manner and can be moved against the closing force of the closing spring into an open position, in which the closing body is spaced from the valve seat , and thereby frees the flow path from the pressure line through the overflow line. The closing body is actuated by means of a control piston, which is rigidly connected to the closing body via a valve rod and can be charged with cleaning liquid under pressure.

A high-pressure cleaning device of the type mentioned before is known from WO 2016/015763 A1. In this high-pressure cleaning device, the pressure present in the pressure line when the cleaning liquid is output acts on one side of the control piston, and on the opposite side the control piston is acted upon by the closing force of the closing spring. The closing force of the closing spring thus acts against the pressing force resulting from the pressure on the control piston of the cleaning liquid present in the pressure line. During the delivery of the cleaning liquid, the pressure of the cleaning liquid may be greater than 100 bar, especially at least 150 bar. It is therefore necessary to use a very strong closing spring whose closing force on the control piston must be carefully adjusted during assembly in order to ensure that the closing body connected to the control piston is opened when the liquid delivery means is open, ie during the delivery of cleaning liquid , which is securely held in its closed position by means of the closing spring and is moved into its open position against the closing force of the closing spring when the liquid outlet means is closed, ie when a predetermined maximum pressure is exceeded. The strong closing spring required for this results in a considerable size of the overflow valve, and the required adjustment of the closing body makes the assembly of the high-pressure cleaning device difficult.

A high-pressure cleaning device is known from DE 10 2009 049 096 A1, in which the overflow valve can be actuated in dependence on the flow rate of the cleaning liquid present in the pressure line. For this purpose, in the region of the pressure line which is arranged downstream of the non-return valve, a throttle element (in the form of an injector) is arranged, which has a through hole which first narrows and then widens in the flow direction, starting from the furthest point of the through hole. The narrow part shunts the transverse hole. The pressure of the cleaning liquid present in the transverse holes is related to its flow rate and is considered for controlling the overflow valve. In this design, the closing spring of the overflow valve can be constructed weaker and with a smaller overall size, however the use of the injector results in considerable flow losses, since the injector exhibits a non-negligible flow resistance . This in turn leads to higher energy consumption of the high-pressure cleaning device.

SUMMARY OF THE INVENTION

The task of the present invention is therefore to improve a high-pressure cleaning device of the type mentioned at the outset so that the overall size of the overflow valve can be reduced without the use of injectors and the assembly of the high-pressure cleaning device can be simplified.

This task is solved according to the invention in a high-pressure cleaning device of the generic type in that the control piston divides the control chamber into a discharge pressure chamber and an overflow chamber, wherein the discharge pressure chamber is connected by a pressure channel to a pressure line. The area arranged downstream of the non-return valve is connected and has a first through opening, which is passed through in a liquid-tight manner by a piston rod fastened to the control piston, and wherein the overflow chamber is routed through the overflow line The section is connected to the region of the pressure line which is arranged upstream of the non-return valve and has a second through opening which forms the valve seat, wherein the two through openings are not the same size and on which the control piston is located The closing force of the closing spring can be loaded on one side of the larger through-opening.

In the high-pressure cleaning device according to the invention, the control chamber is divided by the control piston into a discharge pressure chamber and an overflow chamber. Preferably, the control piston is surrounded in the circumferential direction by a sealing element, for example a sealing ring, which seals off the discharge pressure chamber with respect to the overflow chamber.

The discharge pressure chamber can be charged with the pressure prevailing in the pressure line downstream of the non-return valve. For this purpose, the outlet pressure chamber is connected via a pressure channel to a region of the pressure line which is arranged downstream of the non-return valve. The overflow chamber forms an area of the overflow line. The overflow chamber is connected by a line section of the overflow line to a region of the pressure line which is arranged upstream of the non-return valve. The overflow chamber can thus be loaded with the pressure prevailing upstream of the non-return valve in the pressure line.

During the delivery of cleaning liquid, the pressure present downstream of the check valve in the pressure line is the same as the pressure present upstream of the check valve in the pressure line, except that the cleaning liquid suffers as it flows through the check valve Except for a small pressure loss. During the discharge of cleaning fluid, therefore, virtually the same pressure exists in the discharge pressure chamber and the overflow chamber, wherein the first piston side of the control piston is acted upon by the pressure prevailing in the discharge pressure chamber, and wherein the pressure of the control piston is The second piston side facing away from the first piston side is acted upon by the pressure prevailing in the overflow chamber.

According to the invention, the discharge pressure chamber has a first through opening through which the piston rod fastened to the control piston passes in a liquid-tight manner. A piston rod extends from the control piston through the discharge pressure chamber to the first through opening. As a result, in the discharge pressure chamber, the area of the control piston that can be acted on by pressure in the direction of the overflow chamber is reduced. The larger the first through opening, the smaller the area that can be loaded with pressure, since this area is reduced due to the piston rod passing through the first through opening. This in turn results in a reduction in the pressing force directed in the direction of the overflow chamber, which acts on the control piston in the discharge pressure chamber.

The overflow chamber likewise has a through opening, which is currently referred to as a second through opening. The second through opening forms the valve seat of the overflow valve. During the delivery of cleaning liquid, the closing body of the overflow valve rests on the valve seat. The closing body is connected to the control piston via the valve stem. The valve stem extends from the control piston through the overpressure chamber to the closing body which rests on the valve seat of the second through-opening. As a result, the area of the control piston that can be acted upon with pressure in the direction of the discharge pressure chamber is reduced in the overflow chamber, and therefore also the pressure acting on the control piston in the overflow chamber in the direction of the discharge pressure. The direction of the cavity points to the extrusion force.

One of the two through openings is larger than the other through opening, according to the invention, for example, the second through opening is larger than the first through opening. The side of the control piston facing the larger through-opening is subjected to a lower pressure load than on the side facing the smaller through-opening.

The resultant pressure load, which acts on the control piston and causes the control piston to move, results from the difference in the pressure loads acting on the control piston in the discharge pressure chamber and the overflow chamber. The different sizes of the two through-openings result in a resultant pressure load which causes the control piston to move in the direction of the larger through-opening. This combined pressure load acts against the closing force of the closing spring, which acts on the control piston on the side facing the larger through opening.

The closing force required to reliably hold the closing body in its closed position during the delivery of cleaning liquid can therefore be kept low. What is decisive for the strength of the required closing force is only the difference between the pressing forces acting on the control piston in the discharge pressure chamber and the overflow chamber. Important for this difference is again the size difference between the two through-openings. The smaller the size difference, the smaller the closing force required.

The squeezing force is related to the pressure of the cleaning liquid present in the pressure line. The greater the pressure, the greater the squeezing force acting on the control piston. Unlike the squeezing force, the closing force exerted by the closing spring on the control piston is independent of the pressure of the cleaning liquid. If the pressure in the pressure line exceeds a preset maximum value, the closing force exerted by the closing spring on the control piston is not sufficient to hold the control piston firmly, instead the control piston moves under the pressure load and communicates with the valve stem via the valve stem. The closing body of the control piston connection lifts from the valve seat and releases the flow path from the pressure line through the overflow line, so that the cleaning liquid flows out of the pressure line and thereby the pressure in the pressure line can be reduced.

In order to hold the closing body in its closed position, the closing spring only has to act on the control piston, which is rigidly connected to the closing body via the valve rod, with a closing force corresponding to the difference between the pressing forces acting on the control piston. This allows the use of a closing spring with a relatively small overall size without having to arrange an injector in the pressure line for this purpose. Due to the absence of an ejector, flow losses of the cleaning liquid under pressure can be kept small in the high-pressure cleaning device according to the invention.

The closing spring is preferably arranged in the overflow chamber.

In an advantageous embodiment of the invention, the closing spring is sandwiched between the control piston and the valve seat element, wherein the valve seat element forms the second through opening and the valve seat.

In a preferred embodiment of the invention, the control piston carries a valve stem on its side facing the second through opening, the valve stem passing through the overflow chamber and the second through opening, and on its side from the overflow A closing body is mounted on the area of the chamber protruding, and wherein the valve seat is arranged on the side of the valve seat element facing away from the overflow chamber, and the closing body can be acted upon against the closing force of the closing spring to be in the overflow chamber the pressure of the cleaning fluid present in it. In this embodiment of the invention, the closing body is arranged on the side of the valve seat element facing away from the overflow chamber and in the closed position is acted upon by the pressure prevailing in the overflow chamber through the second through opening. The compressive loading acts against the closing force of the closing spring. The pressure acting on the closing body acts on the control piston through the valve stem, so that the control piston not only bears the pressing force acting directly on the control piston but also the pressing force acting on the closing body.

Advantageously, the closing spring is configured as a helical spring surrounding the valve stem.

In an advantageous embodiment of the invention, the piston rod and the valve rod are designed cylindrically and have different diameters. In particular, it can be provided that the diameter of the piston rod is larger than the diameter of the valve rod.

It is particularly advantageous if a sliding sleeve is arranged in the control chamber, in which the control piston is movably mounted. Preferably, the control piston has a sealing ring, which bears against the sliding sleeve in a fluid-tight manner. The sealing ring surrounding the control piston in the circumferential direction slides on it along the sliding sleeve when the control piston is moved, and the frictional force between the sealing ring and the sliding sleeve can be kept low by suitable material selection. In the event of wear, the sliding sleeve can be replaced in a simple manner.

The sliding sleeve preferably consists at least partially, in particular completely, of plastic material or of metal.

In a preferred embodiment of the invention, the control piston has a first piston part and a second piston part rigidly connected to the first piston part.

The two piston parts can advantageously be connected to one another in a releasable manner. In particular, it can be provided that the two piston parts can be screwed together.

The piston rod is advantageously arranged on the first piston part.

Preferably, the first piston part is integrally connected with the piston rod.

The first piston part and the piston rod are preferably constructed as a one-piece component of metal or plastic material.

The valve stem is advantageously arranged on the second piston part.

It can be provided that the second piston part is connected in one piece with the valve stem.

Alternatively, it can be provided that the second piston part is releasably or non-releasably connected to the valve stem. In particular, it can be provided that the second piston part can be screwed to the valve stem.

It is particularly advantageous if a pressure relief valve is integrated in the control piston, which releases the discharge as a function of the pressure difference between the pressure of the cleaning liquid present in the discharge pressure chamber and the pressure of the cleaning liquid present in the overflow chamber The flow path between the pressure chamber and the overflow chamber. If the pressure difference reaches a preset limit value, pressure compensation can be performed via the pressure relief valve by opening the pressure relief valve. If the pressure difference is less than the preset limit value, the pressure relief valve is closed.

The outlet pressure chamber is connected via a pressure channel to a region of the pressure line which is arranged downstream of the non-return valve. The overflow chamber is connected to a region of the pressure line arranged upstream of the non-return valve via a first line section of the overflow line. Preferably, a second line section of the overflow line is connected to the valve seat of the overflow valve, and the flow connection between the overflow chamber and the second line section of the overflow line can depend on cleaning by means of the overflow valve The pressure of the liquid comes to release and interrupt. The cleaning liquid placed under pressure can be conveyed to a liquid output device, such as a spray gun or a spray boom, via a pressure line and a liquid output line coupled to a pressure connection of the high-pressure cleaning device. If the liquid outlet means is open, the cleaning liquid under pressure flows through the pressure line, wherein the non-return valve is open and the overflow valve is closed. If the liquid output device is closed, the pressure of the cleaning liquid increases based on the pump action in the pressure line. If the pressure of the cleaning liquid exceeds a preset maximum value, the overflow valve opens and the cleaning liquid can flow out of the pressure line through the overflow line, eg to the suction line. The non-return valve is here transferred into its closed position and thus interrupts the flow connection between the region of the pressure line arranged upstream of the check valve and the region of the pressure line arranged downstream of the check valve. In order to ensure that the area of the pressure line arranged downstream of the non-return valve also experiences a pressure drop, a pressure relief valve is preferably integrated into the control piston, which is transferred to it due to the high pressure present downstream of the non-return valve in the pressure line The open position and thus release the flow connection between the discharge pressure chamber and the overflow chamber. As a result, the pressure of the cleaning liquid present downstream of the non-return valve can be reduced in that the cleaning liquid can flow from the region of the pressure line downstream of the non-return valve through the pressure channel, the outlet pressure chamber and the open pressure relief valve to The overflow chamber and the flow from the overflow chamber through the second circuit section of the overflow circuit, for example, to the suction circuit. Therefore, when closing the liquid outlet means, the pressure in the liquid outlet line, eg the high-pressure hose, is reduced. This makes it easier for the user to subsequently open the liquid delivery device again.

The pressure relief valve integrated into the control piston preferably has a valve body, which can be loaded with a closing force by a valve spring, under the action of which the valve body rests on the valve seat. If the pressure of the cleaning liquid present downstream of the non-return valve in the pressure line exceeds a preset value, the valve body of the pressure relief valve is transferred against the action of the valve spring into an open position, in which the valve body releases the Flow path between discharge pressure chamber and overflow chamber.

It is particularly advantageous if the pump has a valve chamber into which the overflow device with the overflow valve can be inserted in the form of a preassembled component. This facilitates the assembly of the high-pressure cleaning device. The preassembled assembly preferably has the valve seat element and closing body of the overflow valve, the control piston and piston rod, the valve rod and the closing spring, which is supported on the one hand on the control piston and on the other hand on the valve seat element superior. As already mentioned, the pressure relief valve can be integrated into the control piston.

Description of drawings

The subsequent description of advantageous embodiments in conjunction with the drawings serves to explain the invention in detail. in:

Figure 1 shows a schematic side view of a high-pressure cleaning device;

Figure 2 shows a partial cross-sectional view of the pump of the high pressure cleaning apparatus of Figure 1;

FIG. 3 shows an enlarged view of the overflow device of the pump of FIG. 2 , wherein the overflow device is constructed with pre-assembled structural components and has an overflow valve.

Detailed ways

In the drawings, an advantageous embodiment of the high-pressure cleaning device according to the invention is shown schematically and generally designated by the reference numeral 10 . The high-pressure cleaning device 10 has a motor 12 which drives a pump 14 and is designed as an electric motor in the exemplary embodiment shown. The pump 14 has a cylinder head 16 , which forms a plurality of pump chambers, wherein in the figures, for a better overview, only one of the three pump chambers in total is shown schematically and designated with the reference number 18 To represent. A piston 20 sinks into the pump chamber 18 and is driven by the motor 12 for reciprocating motion. The pump chamber 18 is connected to a suction connection 26 via an inlet valve 22 and a suction line 24 , and the pump chamber 18 is connected to a pressure connection 32 via an outlet valve 28 and a pressure line 30 .

In a conventional manner, a liquid delivery line known per se and therefore not shown in order to obtain a better overview, for example a suction hose, can be coupled to the suction connection 26 , by means of which the pump 12 can be delivered to the pump 12 . Cleaning liquid under pressure, preferably water. In a conventional manner, a liquid outlet line known per se and therefore not shown in the figures for a better overview, eg a high-pressure hose, can be connected to the pressure connection 32 at its free end. Have liquid output devices that can be closed, such as spray guns or booms. The liquid delivery device can be supplied with cleaning liquid through the liquid delivery line, which is brought under pressure by the pump 14 .

Arranged in the pressure line 30 is a non-return valve 34 which is preferably designed without a spring and has a non-return valve body 36 . The non-return valve body 36 can be placed in a liquid-tight manner on the non-return valve seat 40 with the sealing ring 38 interposed therebetween, and in order to output the cleaning liquid which is placed under pressure, the non-return valve body can occupy the position in the drawing. In the open position, not shown, the non-return valve body is arranged at a distance from the non-return valve seat 40 .

The cylinder head 16 has a valve chamber 42 of stepped design, which can be closed off in a liquid-tight manner by means of a closing plug 44 , and an overflow device 46 is inserted into the valve chamber in the form of a preassembled structural unit.

The valve chamber 42 has a first inwardly directed step 48 at a distance from the closing plug 44 , and at a distance from the first step 48 the valve chamber 42 has a second inwardly directed step 50 .

The valve chamber 42 is of cylindrical design and accommodates in the region between the closing plug 44 and the first step 48 a sliding sleeve 52 which abuts against the valve chamber 42 with the sealing ring 54 interposed therebetween. on the wall. In the embodiment shown, the sliding sleeve 52 is made of plastic material. The sliding sleeve can also be made of metal.

The sliding sleeve 52 encloses a control chamber 56 in the region between the closing plug 44 and the first step 48 , the control chamber extends to the second step 50 , and the control piston 58 is able to be parallel to the longitudinal axis 60 of the valve chamber 42 . The way of ground movement remains in the control chamber. The control piston 58 has an annular groove extending in the outer circumferential direction of the control piston 58 , in which is arranged a second sealing ring 62 , which bears against the sliding sleeve 52 in a fluid-tight manner.

The control piston 58 divides the control chamber 56 into a discharge pressure chamber 64 and an overflow chamber 66 . The outlet pressure chamber 64 is arranged between the control piston 58 and the closing plug 44 and is connected via a pressure channel 68 to a region of the pressure line 30 arranged downstream of the non-return valve 34 .

The overflow chamber 66 is arranged between the control piston 58 and the valve seat element 70 arranged on the second step 50 and through the arrangement of the first line section 72 of the overflow line 74 and the pressure line 30 at the check valve 34 Upstream zone connections. The second line section 76 of the overflow line 74 is connected to the second step 50 of the valve chamber 42 and opens into the suction line 24 .

The valve seat element 70 is surrounded by a third sealing ring 78 which bears against the wall of the valve chamber 42 in a liquid-tight manner.

On its side facing the discharge pressure chamber 64 , the control piston 58 has a piston rod 94 , which is oriented coaxially to the longitudinal axis 60 of the valve chamber 42 . The closing plug 44 has a first through opening 96 oriented coaxially to the longitudinal axis 60 . The piston rod 94 passes through the discharge pressure chamber 64 and the first through opening 96 , wherein the piston rod is surrounded by a fourth sealing ring 98 . The piston rod 94 projects from the discharge pressure chamber 64 with a free end 100 facing away from the control piston 58 .

The valve seat element 70 has a second through opening 80 oriented coaxially to the longitudinal axis 60 of the valve chamber 42 , the second through opening forming an overflow at its end facing the second line section 76 of the overflow line 74 . Valve seat 82 of flow valve 84 . In the closed position shown in FIGS. 2 and 3 , the closing body 86 of the overflow valve 84 , which expands conically in the direction of the second line section 76 , bears against the valve seat 82 in a liquid-tight manner. The closing body 86 is rigidly connected to the control piston 58 via a valve rod 88 . The valve rod 88 is aligned coaxially to the longitudinal axis 60 , passes through the overflow chamber 66 and the second through opening 80 , and projects with its free end 90 facing away from the control piston 58 into the second line section of the overflow line 74 . 76.

The valve rod 88 is surrounded by a closing spring 92 designed as a coil spring, which is clamped between the control piston 58 and the valve seat element 70 and acts on the control piston 58 with a closing force.

The piston rod 94 is of cylindrical design like the valve rod 88 , wherein the diameter of the piston rod 94 is greater than the diameter of the valve rod 88 . The first through opening 96 is of cylindrical design like the second through opening 80 . The diameter of the first through opening 96 is only slightly larger than the diameter of the piston rod, whereas the diameter of the second through opening 80 is significantly larger than the diameter of the valve rod 88 . In the region of the second through-opening 80 , the valve stem 88 is surrounded by an annular space 89 through which the annular surface 91 of the closing body 86 can be acted upon with the pressure of the cleaning liquid present in the overflow chamber 66 . The diameter of the first through opening 96 is smaller than the diameter of the second through opening 80 and therefore also smaller than the diameter of the valve seat 82 . The diameter of the first through opening 96 may be, for example, 4.0 mm, and the diameter of the second through opening 80 and the valve seat 82 may be, for example, 4.3 mm.

The control piston 58 has a first piston portion 102 and a second piston portion 104 . The first piston part 102 is connected in one piece with the piston rod 94 and together with the piston rod 94 forms a one-piece component made of metal or of plastic material. The second piston part 104 forms an annular piston section 106 which has a second sealing ring 62 on its outer side and to which the piston skirt 108 is integrally connected. The piston skirt 108 is rigidly connected to the valve stem 88 by means of a screw connection 110 .

The first piston part 102 has a piston sleeve 112 , which sinks into the annular piston section 106 of the second piston part 104 and is connected to the second piston part by means of a screw connection with a fifth sealing ring 114 interposed therebetween. 104 is detachably connected.

Integrated into the control piston 58 is a pressure relief valve 116 which has a spherical valve body 118 which is pressed against a valve seat 122 by a valve spring 120 .

The first piston part 102 has a first radial bore 124 to which a stepped axial bore 126 , which axially passes through the piston sleeve 112 , is coupled, the axial bore forming the valve seat 122 . Via the first radial bore 124 , the axial bore 126 and the second radial bore 128 of the second piston part 104 , the outlet pressure chamber 64 is in flow connection with the overflow chamber 66 , the flow connection being possible by means of a spring-loaded valve body 118 . , is released and interrupted depending on the pressure difference between the pressure of the cleaning liquid present in the discharge pressure chamber 64 and the pressure of the cleaning liquid present in the overflow chamber 66 .

The outlet pressure chamber 64 and thus also the first piston side 132 of the control piston 58 facing the outlet pressure chamber 64 can be acted upon via the pressure channel 68 with the pressure of the cleaning liquid present in the pressure line 30 downstream of the non-return valve 34 . . The overflow chamber 66 and thus also the second piston side 134 of the control piston 58 facing the overflow chamber 66 can be charged with the cleaning liquid present upstream of the non-return valve 34 via the first line section 72 of the overflow line 74 . pressure. The pressure of the cleaning liquid on the first piston side 132 exerts a first pressing force oriented parallel to the longitudinal axis 60 and directed opposite the closing force of the closing spring 92 on the control piston 58 and the effect of the cleaning liquid on the first pressing force. The pressure on the second piston side 134 exerts a second pressing force oriented parallel to the longitudinal axis 60 and directed opposite the first pressing force on the control piston 58 . In addition, the control piston 58 is acted upon in the closed position of the closing body 86 with a pressing force resulting from the action of the pressure which acts on the annular surface 91 in the closed position of the closing body 86 and is transmitted via the valve rod 88 . to the control piston 58 .

If cleaning liquid under pressure is output from the high-pressure cleaning device 10 , the check valve 34 opens and the pressure of the cleaning liquid present upstream of the check valve 34 in the pressure line 30 and the check in the pressure line 30 The pressure of the cleaning liquid present downstream of the valve 34 is just as great, except for the small pressure loss that the cleaning liquid suffers in the pressure flow of the springless check valve 34 . Therefore, virtually the same pressure exists in the discharge pressure chamber 64 as exists in the overflow chamber 66 , and the pressing force acting on the control piston 58 is determined by the magnitude of the first piston side 132 and the second piston side 134 and the The size of the annular surface 91 of the closing body 86 results in that the annular surface is loaded with the pressure prevailing in the overflow chamber 66 . The diameter of the valve seat 82 of the relief valve 84 is greater than the diameter of the first through opening 96 , whereas the two piston sides 132 , 134 are of the same size. The result of this is that the control piston 58 is acted upon by a resulting differential pressure, which is directed against the closing force of the closing spring 92 . The closing spring 92 acts in the opposite direction of the applied differential pressure, so that the closing body 86 reliably assumes its closing position during the delivery of the cleaning liquid put under pressure and thus interrupts the passage from the pressure line 30 through the overflow line 74 to the suction Flow connection for line 24. The closing force of the closing spring 92 required for this is relatively low, so that the closing spring 92 can have a small overall size.

If the output of the cleaning liquid put under pressure is interrupted, an increased pressure will develop in the pressure lines upstream and downstream of the check valve 34 as long as the pump 14 is not switched off. The increased pressure of the cleaning fluid acts on the first piston side 132 via the pressure channel 68 and the discharge pressure chamber 64 and on the second piston side 134 via the first line section 72 of the overflow line 74 and the overflow chamber 66 . and on the annular surface 91 of the closing body 86 which can be acted upon with the pressure of the cleaning liquid present in the overflow chamber 66 . The increased pressure of the cleaning liquid results in an increased differential pressure, which acts in opposition to the closing force of the closing spring 92 . If the pressure in the pressure line 30 exceeds a preset maximum value, the control piston 58 moves against the closing force of the closing spring 92 in the direction of the valve seat element 70 so that the closing body 86 lifts off the valve seat 82 and takes over the opening Location. Therefore, starting from the region of the pressure line 30 which is arranged upstream of the non-return valve 34 , the flow connection to the suction line 24 is released via the overflow line 74 and the opened overflow valve 84 . The pressure of the cleaning liquid present in the pressure line upstream of the check valve 34 is significantly reduced. Due to the pressure drop in the region upstream of the non-return valve 34 , the non-return valve 34 is closed, so that a higher pressure acts in the discharge pressure chamber 64 than in the overflow chamber 66 . This results in the opening of the pressure relief valve 116 in that the valve body 118 is lifted from the valve seat 122 against the force of the valve spring 120 and thereby passes through the first radial bore 124 , the axial bore 126 and the second The radial holes 128 free the flow path from the discharge pressure chamber 64 to the overflow chamber 66 . Consequently, the pressure can also be reduced in the region of the pressure line 30 which is arranged downstream of the non-return valve 34 . This makes it possible, in particular, to reduce the pressure in the liquid outlet line connected to the pressure connection 32 .

Since only a springless check valve 34 is arranged in the pressure line 30 , but no further throttle points in the form of injectors are arranged, the cleaning liquid experiences only a small pressure loss when flowing through the pressure line 30 . This reduces the power consumption of the high pressure cleaning device 10 when outputting cleaning liquid.

As already mentioned, the closing spring 92 can have a small overall size. This makes it possible to keep the overall size of the overflow device 46 small, wherein the overflow device 46 can be inserted into the valve chamber 42 in the form of a preassembled structural unit. This likewise simplifies the assembly of the high-pressure cleaning device 10 .

Claims (12)

1. A high-pressure cleaning device (10) having a pump (14) for conveying cleaning liquid, wherein the pump (14) has a suction line (24) and a pressure line (30), and in A non-return valve (34) is arranged in the pressure line (30), and wherein the pump (14) has a relief valve (84) which is dependent on the pressure in the pressure line (30) The pressure of the cleaning liquid present is relieved through the flow path of the overflow line (74) for the outflow of cleaning liquid from the pressure line (30), wherein the overflow valve (84) has a liquid seal in the closed position a closing body (86) resting on the valve seat (82), the closing body being movable against the closing force of the closing spring (92) into an open position spaced from the valve seat (82), and The closing body is connected via a valve rod (88) to a control piston (58) which is movably held in the control chamber (56) and can be loaded with cleaning liquid under pressure, characterized in that the control The piston (58) divides the control chamber into a discharge pressure chamber (64) and an overflow chamber (66), wherein the discharge pressure chamber (64) communicates with the pressure line (30) through a pressure channel (68). The area arranged downstream of the non-return valve (34) is connected and has a first through opening (96) which is fastened in a liquid-tight manner to a piston rod ( 94) through and wherein the overflow chamber (66) is arranged at the check valve (34) through the arrangement of the line section (72) of the overflow line (74) and the pressure line (30) ) upstream area is connected and has a second through opening (80), which forms the valve seat (82), wherein the two through openings (96, 80) are not the same size, and the The control piston (58) can be acted upon on its side facing the larger through opening with the closing force of the closing spring (92). 2. The high-pressure cleaning device according to claim 1, characterized in that the closing spring (92) is arranged in the overflow chamber (66). 3. The high-pressure cleaning device according to claim 1 or 2, characterized in that the closing spring is clamped between the control piston (58) and the second through opening (80) and the valve seat ( 82) between the valve seat elements (70). 4. High-pressure cleaning device according to claim 3, characterized in that the control piston (58) carries the valve stem (88) on its side (134) facing the second through opening (80) ), wherein the valve stem (88) passes through the overflow chamber (66) and the second through opening (80), and the valve stem protrudes from the overflow chamber (66) The closing body ( 86 ) is carried on the area of the valve seat ( 86 ), and wherein the valve seat ( 82 ) is arranged on the side of the valve seat element ( 70 ) facing away from the overflow chamber ( 66 ), and the valve seat ( 82 ) is The closing body (86) can be loaded against the closing force of the closing spring (92) with the pressure of the cleaning liquid present in the overflow chamber (66). 5 . The high-pressure cleaning device according to claim 1 , wherein the piston rod ( 94 ) and the valve rod ( 88 ) are cylindrical in design and have different diameters. 6 . 6 . The high-pressure cleaning device according to claim 1 , wherein a sliding sleeve ( 52 ) is arranged in the control chamber ( 56 ), the control piston ( 58 ) being movable in a movable manner. 7 . is supported in the sliding sleeve. 7 . The high-pressure cleaning device according to claim 1 , wherein the control piston ( 58 ) has a first piston part ( 102 ) and a rigid connection to the first piston part ( 102 ). 8 . The second piston portion (104). 8. The high-pressure cleaning apparatus according to claim 7, wherein the first piston part (102) is integrally connected with the piston rod (94). 9. The high-pressure cleaning device according to claim 7 or 8, characterized in that the second piston part (104) is connected with the valve stem (88) in a releasable manner or in a non-releasable manner , especially screw connections. 10 . The high-pressure cleaning device according to claim 1 , wherein a pressure relief valve ( 116 ) is integrated in the control piston ( 58 ), the pressure relief valve being dependent on the discharge at the outlet. 11 . The pressure difference between the pressure present in the pressure chamber (64) and the pressure present in the overflow chamber (66) releases the pressure between the discharge pressure chamber (64) and the overflow chamber (66). flow path. 11. The high-pressure cleaning device according to claim 10, characterized in that the pressure relief valve (116) has a valve body (118), which can be loaded by a valve spring (120) under its action to make the valve body (118) The closing force of the valve body (118) against the valve seat (122). 12 . The high-pressure cleaning device according to claim 1 , wherein the pump ( 14 ) has a valve chamber ( 42 ), an overflow device ( 46 ) with the overflow valve ( 84 ). 13 . It can be inserted into the valve chamber in the form of a pre-assembled structural component.

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