EP3442713B1 - Valve device and valve gun for a high-pressure cleaning device - Google Patents

Description

The invention relates to a valve device for a high-pressure cleaning device for controlling the flow of a cleaning liquid, in particular for the controlled delivery of a cleaning liquid, with a valve housing which has a passage channel extending from a valve inlet to a valve outlet and in which a valve seat element is arranged which forms a valve seat , and in which a closing body is arranged, which is acted upon by a closing spring with a closing force in the direction of the valve seat and bears against the valve seat in a closed position and can be moved into an open position spaced apart from the valve seat by displacing a valve tappet.

In addition, the invention relates to a valve gun for a high-pressure cleaning device with such a valve device.

With the help of a high-pressure cleaning device, a cleaning liquid can be pressurized and directed at an object to be cleaned. Water is usually used as the cleaning liquid, to which a cleaning chemical can be added. The control of the flow of the cleaning liquid takes place by means of at least one valve device, with the aid of which the delivery of cleaning liquid can be controlled in particular. The valve device has a valve housing with a through channel extending from a valve inlet to a valve outlet. A valve seat element, which forms a valve seat, is arranged in the through-channel. In addition, a closing body is arranged in the through-channel, which is acted upon by a closing spring with a closing force in the direction of the valve seat. By moving a valve tappet of the valve device, the closing body can be moved into an open position spaced apart from the valve seat, in which it establishes a flow connection from the valve inlet to Valve outlet releases. In the closed position of the valve body, the flow connection between the valve inlet and the valve outlet is interrupted.

Pressurized cleaning fluid is often dispensed with the aid of a valve gun which has such a valve device. For example, a pressure hose can be connected to the valve inlet of the valve device, via which the cleaning liquid can be supplied to the valve device, and a spray lance can be connected to the valve outlet, for example, via which the cleaning liquid can be directed onto an object to be cleaned.

The valve seat element and the closing body are often subjected to high loads, since the pressure of the cleaning liquid can be more than 100 bar, in particular more than 150 bar. In addition, the cleaning liquid has a high temperature in many cases, for example a temperature of more than 70 ° C. During the transition from the open position to the closed position, the closing body suddenly exerts a high mechanical load on the valve seat.

In order to withstand the high loads, the DE 89 12 046 U1 mentions the possibility of using a ceramic as the material for the valve seat element and / or for the closing body. However, since in many cases the cleaning liquid contains limescale or rust particles or abrasive particles which are pressed against the valve seat with high energy when the closing body changes from the open position to the closed position and which in the open position of the closing body due to the usually high flow velocity , which has the cleaning liquid in the area of the valve seat, has a grinding effect on the valve seat element, in the DE 89 12 046 U1 proposed to design the valve seat as an elastic sealing member made of an abrasion-resistant material. However, the use of such elastic sealing elements increases the assembly costs of the valve devices. In addition, such elastic sealing members can the high Loads that occur when using strongly heated and high-pressure cleaning fluid often do not withstand for too long.

A manually operable valve with a valve seat element, which forms a valve seat, and with a closing body, which is acted upon by a closing spring with a closing force in the direction of the valve seat, is shown in FIG GB 513 013 A. disclosed. The closing body rests on the valve seat in a closed position and can be moved into an open position spaced apart from the valve seat by moving a valve tappet.

From the EP 2 602 518 A1 A check valve with a spherical closing body and a valve seat element with a valve seat designed complementary to the outer surface of the closing body is known. Ceramic materials such as aluminum oxide or zirconium oxide are proposed for producing the valve seat element and the closing body.

The object of the present invention is to further develop a valve device of the type mentioned at the outset in such a way that it has an improved service life even when using highly heated and high-pressure cleaning fluid.

This object is achieved by a valve device with the features of claim 1.

In the valve device according to the invention, at least the valve seat region of the valve seat element which forms the valve seat consists of an aluminum oxide ceramic which has a very high degree of purity, namely a degree of purity of at least 99.8%, or of a dispersion ceramic based on aluminum oxide with dispersed zirconium oxide. It has been shown that the use of such ceramic materials means that the valve device can withstand the stresses that occur when a strongly heated and high-pressure cleaning fluid is used can withstand reliably without having to use an additional, energy-absorbing elastic material. When using an aluminum oxide ceramic, however, a degree of purity of at least 99.8% is required. Instead of an aluminum oxide ceramic with such a high degree of purity, a dispersion ceramic based on aluminum oxide reinforced with zirconium oxide can also be used. Dispersion ceramics of this type are also referred to as ZTA ceramics, the abbreviation ZTA standing for "Zirconia Toughened Aluminum Oxide".

The ceramic materials used have a high hardness and high impact strength and can therefore withstand the loads which occur when the valve device is used in a high-pressure cleaning device, in particular in a valve gun of a high-pressure cleaning device.

The valve seat element has a conical sealing surface which forms the valve seat. A sealing surface designed in this way can be produced inexpensively and, in particular, also machined inexpensively in order to improve the surface quality.

If the closing body assumes its closed position, the cleaning liquid upstream of the closing body and the valve seat often has a high pressure. The movement of the closing body from the closed position into the open position preferably takes place against the pressure of the cleaning liquid and also against the closing force exerted by the closing spring on the closing body. In order to facilitate the transition of the closing body from the closed position into the open position, the valve seat element has a flow guide surface which is immediately upstream of the sealing surface in the flow direction of the cleaning liquid and which tapers in the flow direction of the cleaning liquid. The sealing surface forms the valve seat against which the closing body rests in the closed position. If the closing body lifts off the sealing surface, cleaning liquid can reach the sealing surface via the flow guide surface and from there through a through opening of the valve seat element Flow through to the valve outlet. It has been shown that the transition of the closing body from the closed position into the open position can be facilitated by the provision of the flow guide surface, which is immediately upstream of the sealing surface in relation to the direction of flow of the cleaning liquid, with a slight lifting of the closing body from the sealing surface the pressure of the cleaning liquid acting on the closing body can be reduced.

It is advantageous if the closing body also consists of an aluminum oxide ceramic with a degree of purity of at least 99.8% or of a dispersion ceramic based on aluminum oxide with dispersed zirconium oxide, at least in a contact area in the closed position on the valve seat. This gives the valve device a particularly high load capacity.

It can be provided that only the valve seat area of the valve seat element and / or the contact area of the closing body in contact with the valve seat in the closed position consist of the ceramic materials mentioned. However, it is advantageous if the valve seat element and / or the closing body consist entirely of an aluminum oxide ceramic with a degree of purity of at least 99.8% or of a dispersion ceramic based on aluminum oxide with dispersed zirconium oxide.

The valve seat element and / or the closing body can be produced from the ceramic materials mentioned in a sintering process. Conveniently, only the valve seat element in the area of the valve seat is subjected to post-processing in order to give the valve seat a high surface quality. For post-processing, the area of the valve seat can be ground or lapped, for example.

It is advantageous if the valve seat element and the closing body consist of the same ceramic material. In such a configuration, either the same aluminum oxide ceramic comes for the valve seat element and for the closing body with a purity of at least 99.8% or the same dispersion ceramics based on aluminum oxide with dispersed zirconium oxide.

The proportion of zirconium oxide in the dispersion ceramics mentioned is advantageously a maximum of 25%.

For example, it can be provided that the sealing surface is ground or lapped in order to improve the surface quality.

The sealing surface preferably has a mean roughness value of at most 1.0 μm, in particular a mean roughness value of at most 0.8 μm. The mean roughness value is understood to mean the arithmetic mean of the deviations from a center line.

The closing body is advantageously spherical.

The flow guide surface is advantageously conical.

The opening angle of the conically shaped flow guide surface is preferably larger than the opening angle of the conically shaped sealing surface. The opening angle here is understood to mean twice the angle between the surface lines and the central axis of the flow guide surface or the sealing surface.

The opening angle of the conical sealing surface can be, for example, approximately 65 ° to 68 °.

The opening angle of the conical flow guide surface can be at least 69 °, for example.

In a preferred embodiment of the invention, the valve seat element is designed to be rotationally symmetrical to a central axis of the valve seat element. The rotationally symmetrical design of the valve seat element facilitates its manufacture. As already mentioned, for example, a sintering process can be used to manufacture the valve seat element.

The valve seat element preferably has a support surface facing away from the valve inlet, by means of which it bears against a narrowing of the diameter of the through-channel assigned to the valve seat element. Which is from the valve inlet The passage channel extending to the valve outlet thus has a diameter constriction on which the valve seat element is supported.

In an advantageous embodiment of the invention, the narrowing of the diameter of the through-channel associated with the valve seat element forms a radially inward step.

In order to seal the valve seat element with respect to the through-channel, it is advantageous if the valve seat element has a recess which surrounds the support surface in the circumferential direction and in which a sealing element is arranged, for example a sealing ring. The recess can, for example, form a step change in the outer diameter of the valve seat element.

The valve seat element can be configured, for example, as a hollow cylinder, the outer diameter of which decreases in stages in the direction of the support surface, the region with the reduced outer diameter being surrounded by a sealing ring.

The valve seat element has a through opening which adjoins the valve seat in the flow direction of the cleaning liquid and extends coaxially to a central axis of the valve seat element and through which the cleaning liquid can flow to the valve outlet when the closing body assumes its open position. It is advantageous if the through opening has an end section facing away from the valve seat, which extends continuously in the direction of flow of the cleaning liquid. It has been shown that the flow resistance of the valve seat element can be reduced as a result, and this in turn has the consequence that the load exerted by the cleaning liquid on the valve seat element can be reduced. The end section can, for example, be conical.

It is expedient if the diameter of the through-channel which extends from the valve inlet to the valve outlet in that in the flow direction of the cleaning liquid directly adjoins the valve seat element The area is larger than the largest diameter of the end section of the through opening of the valve seat element. In such an embodiment, the through opening of the valve seat element preferably forms the region with the smallest flow cross section through which the cleaning liquid flows on the way from the valve inlet to the valve outlet. This area can be kept very short, so that the cleaning liquid is only subject to relatively small flow losses when flowing through the valve device.

A spring holder, on which the closing spring is supported, is preferably fixed in the passage channel, based on the direction of flow of the cleaning liquid, upstream of the valve seat element.

The spring holder is advantageously pressed into a receiving section of the through-channel, the valve seat element, the closing body and the closing spring being arranged in the receiving section. In such a configuration, the spring holder has a press-in area which forms an interference fit with the receiving section of the through-channel, which ensures that the spring holder is held immovably and non-rotatably in the through-channel, and therefore does not move unintentionally under the action of the force exerted by the closing spring.

In an advantageous embodiment of the invention, the receiving section of the through-channel is straight, cylindrical and stepless. This facilitates the manufacture of the valve housing and the assembly of the valve seat element, the closing body and the closing spring as well as the pressing of the spring holder into the receiving section.

It is particularly advantageous if the through-channel has a diameter narrowing associated with the spring holder, on which the spring holder is preferably supported with a support flange. The receiving section of the through-channel can vary, for example, from the narrowing of the diameter associated with the spring holder to that associated with the valve seat element Extend diameter narrowing. When installing the valve device, the valve seat element can be inserted into the receiving section to such an extent that its support surface comes to rest against the constriction of diameter associated with the valve seat element. Subsequently, the closing body and the closing spring can be inserted into the receiving section, and after inserting the closing body and the closing spring, the spring holder with its press-in area can be pressed into the receiving section until it rests with its support flange on the narrowing diameter of the through-channel associated with the spring holder reached. In this position, the spring element is at a predetermined distance from the valve seat element, and this in turn has the consequence that the closing spring, which is supported on the spring holder, exerts a predetermined closing force on the closing body.

The narrowing of the diameter of the through-channel assigned to the spring holder is advantageously designed in the form of a radially inward step.

In an advantageous embodiment of the invention, a force transmission element is arranged between the closing spring and the closing body. With the help of the force transmission element, the closing force exerted by the closing spring can be uniformly transmitted to the closing body, so that in the closed position it lies close to the valve seat, the closing body being subjected to a closing force practically only coaxially to the direction of flow of the cleaning liquid and forces oriented transversely to the direction of flow can be kept low. The force transmission element forms a guide for the closing body.

The force transmission element advantageously consists of a non-ceramic material. For example, it can be provided that the force transmission element consists of metal, in particular brass or steel, or also of a plastic material.

The force transmission element preferably has a spring receiving section for receiving an end region of the closing spring facing the force transmission element and a closing body receiving section for receiving an end region of the closing body facing the force transmission element.

The closing spring is expediently designed as a helical spring which surrounds the spring receiving section with its end region facing the force transmission element or dips into the spring receiving section.

The closing body receiving section preferably forms a depression, for example a pan-like depression, into which the closing body is immersed.

It is particularly advantageous if the spring holder has a longitudinal channel oriented in the flow direction of the cleaning liquid, which extends over an outwardly directed step, the closing spring being supported on the step and at least one bypass channel, based on the flow direction of the cleaning liquid, upstream of the Step, branches off from the longitudinal channel. The bypass channel enables the cleaning liquid to flow around the end region of the closing spring arranged on the spring holder. The flow losses suffered by the cleaning liquid can thereby be kept low.

The at least one bypass channel can be oriented obliquely or perpendicular to the longitudinal channel.

It is advantageous if the at least one bypass channel is designed as a groove which is molded into the end surface of the spring holder facing the closing spring. The closing spring can be supported on the end face of the spring holder, and at least a part of the cleaning liquid can flow around the outside of the region of the closing spring resting on the end face via the groove formed in the end face.

The end surface of the spring holder facing the closing spring preferably has two cross-shaped grooves, each of which form bypass channels.

As mentioned at the outset, the invention also relates to a valve gun for a high-pressure cleaning device with a valve device of the type explained above. The valve gun has a trigger lever which is mechanically coupled to the valve tappet and is pivotally mounted about a pivot axis. The release lever can be pivoted back and forth between a rest position and a release position. When the trigger lever is pivoted from the rest position into the release position, the valve tappet mechanically coupled to the trigger lever is displaced in the direction of the valve inlet, and this in turn has the consequence that the closing body moves from its closed position into its open position. If the release lever is pivoted back from its release position into its rest position, the closing body moves back into the closed position under the action of the closing force acting on it, whereby it moves the valve tappet back into its starting position.

Figur 1:

eine schematische Schnittansicht einer Ventilpistole;

Figur 2:

eine vergrößerte Darstellung einer Ventileinrichtung der Ventilpistole aus Figur 1;

Figur 3:

eine vergrößerte Darstellung von Detail A aus Figur 2;

Figur 4:

eine vergrößerte Schnittansicht eines Ventilsitzelements der Ventileinrichtung aus Figur 2.

The following description of an advantageous embodiment of the invention serves in conjunction with the drawing for a more detailed explanation. Show it:

Figure 1:

a schematic sectional view of a valve gun;

Figure 2:

an enlarged view of a valve device of the valve gun Figure 1 ;

Figure 3:

an enlarged view of detail A. Figure 2 ;

Figure 4:

an enlarged sectional view of a valve seat member of the valve device Figure 2 .

In Figure 1 An advantageous embodiment of a valve gun according to the invention is shown schematically and overall designated by reference number 10. The valve gun 10 comprises a gun housing 12 which is formed in the usual way by a first housing shell 14 and a second housing shell, not shown in the drawing. The gun housing 12 has a central housing region 16 which is arranged between a front housing region 18 and a rear housing region 20.

The front housing area 18 accommodates an advantageous embodiment of a valve device 22 according to the invention. The valve device 22 has a valve housing 24 with a valve inlet 26 and a valve outlet 28. The valve inlet 26 is in flow connection with the valve outlet 28 via a through-channel 30.

In the embodiment shown, the valve outlet 28 protrudes from a front side 32 of the gun housing 12. A liquid discharge line, for example a spray lance, can be connected to the valve outlet 28. In the embodiment shown, the valve inlet 26 protrudes from an underside 34 of the gun housing 12. A liquid supply line can be connected to the valve inlet 26. In the illustrated embodiment, a pressure hose 36 is connected to the valve inlet 26. The pressure hose 36 has a hose nipple 38 which is inserted into the valve inlet 26 of the valve housing 24 and is fixed on the valve housing 24 by means of a union nut 40. The union nut 40 is surrounded by a kink protection 42 in the illustrated embodiment.

A handle 44 protrudes from the rear housing area 20 of the gun housing 12, from the free end area 46 of which, in the embodiment shown, a protective bracket 48 extends to the front housing area 18. The protective bracket 48, the central housing area 16 and the handle 44 surround an engagement opening 50 into which the user can engage with his fingers.

The valve device 22 is in Figure 2 shown enlarged. As can be seen, the through-channel 30 has a straight first channel section 52 which adjoins the valve inlet 26 in the flow direction 54 of the cleaning liquid. At a distance from the valve inlet 26, the first channel section 52 has a first radially inwardly directed step 56, and in the flow direction 54 at a distance from the first step 56, the first channel section 52 has a second radially inwardly directed step 58. Downstream of the second stage 58, the first channel section 52 forms an end region 60. A second channel section 62 adjoins the end region 60, which is aligned at an angle to the first channel section 52, that is to say the longitudinal axis 64 of the second channel section 62 is aligned at an angle to the longitudinal axis 66 of the first channel section. In the embodiment shown, the angle between the longitudinal axis 64 and the longitudinal axis 66 is more than 90 °, in particular approximately 115 °.

In the embodiment shown, a third duct section 68 of the through duct 30 adjoins the second duct section 62. The third channel section 68 extends from the second channel section 62 to the valve outlet 28 of the valve housing 24. The longitudinal axis 70 of the third channel section 68 is oriented at an angle to the longitudinal axis 64 of the second channel section 62. In the embodiment shown, the longitudinal axis 70 of the third channel section 68 runs perpendicular to the longitudinal axis 66 of the first channel section 52.

In addition to the through-channel 30, the valve housing 24 has a stepped tappet channel 72 which is aligned with the first channel section 52 and adjoins the end region 60 of the first channel section 52. The tappet channel 72 extends to an upper side 74 of the valve housing 24 facing away from the valve inlet 26. Starting from the upper side 74, the tappet channel 72 has an input section 76, at which a step-widening 78 opens into the end region 60 of the first channel section 52 Output section 80 connects.

Approximately midway between the valve inlet 26 and the first step 56, the first channel section 52 has a conical narrowing 82, via which the diameter of the first channel section 52 is reduced. The hose nipple 38 is inserted in the region of the first channel section between the valve inlet 26 and the first stage 56. The hose nipple 38 has an annular groove in which a sealing ring 86 is arranged, which seals the hose nipple 38 in a region downstream of the conical constriction 82 against the wall of the first channel section 52.

The area of the first channel section 52 extending from the first step 56 to the second step 58 is linear, cylindrical and stepless and forms a receiving area 88. A spring holder 90 is supported with a support flange 92 on the first step 56 and is pressed into the receiving area 88 with a press-in area 94 adjoining the support flange 92 in the flow direction 54. The first stage 56 forms a narrowing of the diameter of the through-channel 30 associated with the spring holder 90. The press-in area 94 thus forms a press fit together with the receiving area 88. The press-in area 94 is cylindrical. An outlet area 96 of the spring holder 90 adjoins the press-in area 94 in the flow direction 54. The outside diameter of the exit area 96 is smaller than the outside diameter of the press-in area 94. The exit area 96 extends up to an end face 98 of the spring holder 90 facing the second step 58. Two grooves 100, 102 aligned perpendicular to one another and a central one are formed in the end face 98 Depression 104. The grooves 100, 102 have a greater depth than the central depression 104.

In the longitudinal direction, that is to say in the flow direction 54, the spring holder 90 is penetrated by a longitudinal channel 106, from which the grooves 100, 102 branch off in the radial direction.

A valve seat element 108 made of a ceramic material is supported on the second stage 58, which is designed as a stepped hollow cylinder and forms a valve seat 110 facing the spring holder 90. The second stage 58 forms a narrowing of the diameter of the through-channel 30 associated with the valve seat element 108. The valve seat 110 is adjoined coaxially to the longitudinal axis 66 of the first channel section 52 by a passage opening 112 which extends through the valve seat element 108 in the longitudinal direction and widens conically in the direction of the end region 60 of the first channel section 52. The valve seat element 108 is designed to be rotationally symmetrical with respect to a central axis 115. This is particularly apparent from Figure 4 clear.

In the embodiment shown, the valve seat element 108 consists of an aluminum oxide ceramic which has a degree of purity of at least 99.8%. Alternatively, the valve seat element 108 could also consist of a dispersion ceramic based on aluminum oxide with dispersed zirconium oxide, i.e. made from a ZTA material.

The ceramic valve seat element 108 has an area with a reduced outer diameter in the form of a collar 114, which is surrounded by a sealing ring 116 and which bears against the second step 58 with a support surface 118. Contrary to the direction of flow 54 of the cleaning liquid, the collar 114 is adjoined by a radially outwardly directed shoulder 120, via which the outer diameter of the valve seat element 108 widens in stages. By means of the sealing ring 116, the valve seat element 108 is held sealed in the first channel section 52 both in the axial direction and in the radial direction with respect to the longitudinal axis 66 of the first channel section 52.

How out Figure 4 becomes clear, the valve seat 110 is formed by a conical sealing surface 111. The valve seat element 108 was produced in a sintering process and the sealing surface 111 was subsequently machined so that it has a high surface quality. In the exemplary embodiment shown, the sealing surface 111 was ground, for example it could also be lapped. The mean roughness of the sealing surface 111 is at most 1.0 μm, in particular at most 0.8 μm.

In relation to the direction of flow 54 of the cleaning liquid, the sealing surface 111 is immediately upstream of a likewise conical flow guide surface 113. In contrast to the sealing surface 111, the flow guide surface 113 was not ground and was also not subjected to any other post-processing.

The opening angle β of the flow guide surface 113 is greater than the opening angle α of the sealing surface 111. In the exemplary embodiment shown, the opening angle α is approximately 65 ° to 68 ° and the opening angle β is at least approximately 69 °.

In relation to the flow direction 54 upstream of the valve seat element 108, a closing body 122 is arranged in the receiving area 88 of the through-channel 30, which is spherical in the exemplary embodiment shown. In the exemplary embodiment shown, the closing body 122 consists of the same aluminum oxide ceramic as the valve seat element 108 and was likewise produced in a sintering process. Alternatively, a dispersion ceramic based on aluminum oxide with dispersed zirconium oxide could also be used for the closing body 122.

In the in the Figures 1 , 2nd and 3rd In the closed position shown, the closing body 122 bears against the valve seat 110. A closing force is applied to the closing body 122 by means of a closing spring 124, so that it is pressed against the valve seat 110. In the exemplary embodiment shown, the closing spring 124 is designed as a helical spring. With its end facing away from the closing body 122, it is supported on the spring holder 90, wherein it dips into the central recess 104 thereof. With its end region facing the closing body 122, the closing spring 124 surrounds a cylindrical spring receiving section 126 of a force transmission element 128, via which the closing force exerted by the closing spring 124 on the closing body 122 is transmitted. The force transmission element 128 has a closing body receiving section 130 facing the closing body 122 in the form of a recess into which the closing body 122 is immersed with its end region facing away from the valve seat 110.

The tappet channel 72 is penetrated by a valve tappet 132, which extends as far as the closing body 122 and with its free end 134 protrudes from the upper side 74 of the valve housing 24. In the area of the output section 80 of the tappet channel 72, the valve tappet 132 is surrounded by a sealing ring 136, which is positioned between a support ring 138 which rests on the stepped extension 78 of the tappet channel 72 and a scraper ring 140 arranged at a distance from the support ring 138. The support ring 138 avoids a gap extrusion of the sealing ring 136, i.e. it ensures that the sealing ring 136 is not squeezed into the gap between the valve tappet 132 and the wall of the inlet section 76 of the tappet channel 72 under the action of very high liquid pressures.

As explained in more detail below, the valve tappet 132 can be moved colinearly to the longitudinal axis 66 of the first channel section 52, its outside being stripped off by the scraper ring 140 and any limescale deposits and other deposits of abrasive particles thereby being removed. The support ring 138, the scraper ring 140 and the sealing ring 136 are held in the outlet section 80 of the tappet channel 72 by means of a clamping disk 142 pressed into the outlet section 80.

The valve tappet 132 can be displaced in the direction of the valve inlet 26 by pivoting a release lever 144, so that the closing body 122 lifts against the closing force of the closing spring 124 from the valve seat 110 and thereby releases the flow connection between the valve inlet 26 and the valve outlet 28. The release lever 144 is arranged in the handle 44 and is mounted on the first housing shell 14 and the second housing shell (not shown in the drawing) so that it can pivot about a pivot axis 146. He can use the heel of his hand from the user Figure 1 shown Rest position in the direction of the front housing area 18 are pivoted. The pivot axis 146 is arranged in the free end region 46 of the handle 44. In its rest position, the trigger lever 144 protrudes with an actuating surface 148 from the rear of the handle 44 facing away from the front housing area 18.

The release lever 144 is acted upon by a first restoring spring 150 with a resilient restoring force. Under the action of the first return spring 150, the trigger lever 144 automatically assumes its rest position when the user releases the trigger lever 144.

In the rest position, the release lever 144 is automatically locked by means of a first locking member 152. For this purpose, the first locking member 152 is essentially L-shaped and is pivotably mounted in the handle 44. In the rest position of the release lever 144, a first leg 154 of the first locking member 152 protrudes from the front of the handle 44 facing the front housing area 18. A second leg 156 of the first locking member 152 facing the release lever 144 lies in the rest position of the release lever 144 with its free end 158 on the release lever 144 and prevents the latter from pivoting. By means of a second return spring 160, the first locking member 152 is inserted into its Figure 1 shown locking position pressed. If the user grips the handle 44 with his hand, he intuitively pivots the first locking member 152 with his fingers against the spring force of the second return spring 160 into a position in which the second leg 156 can dip into a recess 162 of the release lever 144 and thereby the Release lever 144 can be pivoted freely about the pivot axis 146 by the first locking member 152. If the user releases the handle 44 again, the release lever 144 is automatically pivoted into its rest position by the first return spring 150 and the first locking element 152 is automatically pivoted into the locking position by the second return spring 160, in which it locks the release lever 144.

A pivoting movement of the release lever 144 in the direction of the front housing area 18 is transmitted to the valve lifter 132 via a coupling lever 164 arranged in the central housing area 16. In the exemplary embodiment shown, the coupling lever 164 is mounted on the valve housing 24 so as to be pivotable about a coupling axis 166. The coupling axis 166 is aligned parallel to the pivot axis 146. At a short distance from the coupling axis 166, the coupling lever 164 has an adjustable force application element 168 which bears against the free end of the valve lifter 132. At its rear end facing the release lever 144, the coupling lever 164 is spaced apart from one another by a first coupling roller 170 and a second coupling roller 172 which, when the trigger lever 144 is pivoted in the direction of the front housing region 18, successively slide along a region of a guideway 174 which extends from an end face 176 of the release lever 144 facing the coupling lever 164 is formed. If the trigger lever 144 is pivoted in the direction of the front housing region 18, the first coupling roller 170 first slides along a rear end region of the guide track 174 and the coupling lever 164 is pivoted such that the force application element 168 pushes the valve tappet 132 in the direction of the inlet 26 of the valve housing 24 shifts. When the trigger lever 144 is pivoted further in the direction of the front housing region 18, the first coupling roller 170 lifts off the guide track 174 and the second coupling roller 172 slides along a front end region of the guide track 174, so that the coupling lever 164 is pivoted further and thereby the valve tappet 132 is moved further in the direction of the inlet 26 until the closing body 122 reaches its open position.

If the user releases the release lever 144 again, the actuating force acting on the coupling lever 164 from the release lever 144 is eliminated, so that the closing body 122 resumes its closed position under the action of the closing force exerted by the closing spring 124, the valve tappet 132 in the valve inlet 26 shifted away is and thereby also the coupling lever 164 is pivoted back into its original position.

The trigger lever 144 takes its in Figure 1 shown rest position, the coupling lever 164 can be locked with the aid of a second locking member 178. The second locking member 178 forms a sliding body 180 which is displaceably mounted on the first housing shell 14 and on the second housing shell Figure 1 illustrated blocking position with a projection 182 facing the coupling lever 164 directly abuts the top of the coupling lever 164 facing away from the first coupling roller 170 or is arranged at a short distance from the top of the coupling lever 164. A pivoting movement of the coupling lever 164 and thus also a pivoting movement of the trigger lever 144 is thus reliably prevented with the help of the sliding body 180 when the sliding body 180 is in its Figure 1 shown locked position occupies. From this locked position, the sliding body 180 can be moved rearward in the direction facing away from the front housing area 18 into a parking position, not shown in the drawing, so that the projection 182 releases the coupling lever 164 and this from the release lever 144 via the first coupling roller 170 and the second Coupling roller 172 can be pivoted. Both in the locked position and in the park position, the sliding body can be locked with the gun housing 12 by means of suitable locking elements.

Due to the use of an aluminum oxide ceramic with a high degree of purity (at least 99.8%) or alternatively a dispersion ceramic based on aluminum oxide with dispersed zirconium oxide for the valve seat element 108 and the closing body 122, the valve device 22 and the valve gun 10 have a high load capacity and a long service life .

The valve device 22 and the valve gun 10 are inexpensive to manufacture. To assemble the valve device 22, the support ring 138 and the wiper ring 140 together with the sealing ring 136 can be via the valve inlet 26 and the first channel section 52 are inserted into the output section 80 of the tappet channel 72. The clamping disk 142 can then be pressed into the output section 80 of the tappet channel 72 via the valve inlet 26 and the first channel section 52. In a subsequent assembly step, the valve seat element 108, which is made of a ceramic material, can be inserted together with the sealing ring 116 into the receiving area 88 via the valve inlet 26 until the end face 118 of the collar 114 bears against the second step 58 of the first channel section 52. In a subsequent assembly step, the closing body 122, which is also made of a ceramic material, and the closing spring 124, together with the force transmission element 128, can be inserted into the receiving area 88 via the valve inlet 26, and in a further assembly step, the spring holder 90 with its press-in area 94 can be inserted so far into the Receiving area 88 are pressed in that the support flange 92 abuts the first step 56 of the first channel section 52. Finally, the valve tappet 132 can then be inserted into the tappet channel 72 from the top 74 of the valve housing 24, reaching through the support ring 138, the sealing ring 136, the scraper ring 140 and the clamping disk 142 and finally coming into contact with the ceramic closing body 122.

Claims (23)

1. Valve device for a high-pressure cleaning appliance for controlling the flow of a cleaning liquid, in particular for dispensing a cleaning liquid in a controlled manner, having a valve housing (24) that comprises a through-channel (30) extending from a valve inlet (26) to a valve outlet (28), in which a valve seat element (108) that forms a valve seat (110) is arranged and in which a closing body (122) is arranged that is applied with a closing force in the direction of the valve seat (110) by a closing spring (124) and abuts against the valve seat (110) in a closing position and is movable into an open position at a distance from the valve seat (110) by displacing a valve plunger (132), characterized in that the valve seat element (108) consists, at least in a valve seat region forming the valve seat (110), of an aluminum oxide ceramic with a degree of purity of at least 99.8% or of a dispersion ceramic on the basis of aluminum oxide with dispersed zirconium oxide, and in that the valve seat element (108) has a conical sealing surface (111) that forms the valve seat (110), as well as a flow-guiding surface (113) which is arranged directly upstream of the sealing surface (111) in the flow direction (54) of the cleaning liquid and tapers in the flow direction (54) of the cleaning liquid.
2. Valve device in accordance with Claim 1, characterized in that the closing body (122) consists, at least in an abutment region adjoining the valve seat (110) in the closing position, of an aluminum oxide ceramic with a degree of purity of at least 99.8% or of a dispersion ceramic on the basis of aluminum oxide with dispersed zirconium oxide.
3. Valve device in accordance with Claim 1 or 2, characterized in that the valve seat element (108) and/or the closing body (122) consist entirely of an aluminum oxide ceramic with a degree of purity of at least 99.8% or of a dispersion ceramic on the basis of aluminum oxide with dispersed zirconium oxide.
4. Valve device in accordance with Claim 3, characterized in that the valve seat element (108) and the closing body (122) consist of the same ceramic material.
5. Valve device in accordance with any one of the preceding Claims, characterized in that the sealing surface (111) is ground or lapped.
6. Valve device in accordance with any one of the preceding Claims, characterized in that the flow-guiding surface (113) is of conical configuration.
7. Valve device in accordance with Claim 6, characterized in that the opening angle (β) of the flow-guiding surface (113) is greater than the opening angle (α) of the sealing surface (111).
8. Valve device in accordance with any one of the preceding Claims, characterized in that the valve seat element (108) is configured rotationally symmetrical to a middle axis (115).
9. Valve device in accordance with any one of the preceding Claims, characterized in that the valve seat element (108) comprises a supporting surface (118) remote from the valve inlet (26), with which it abuts against a diameter constriction of the through-channel (30) associated with the valve seat element (108).
10. Valve device in accordance with Claim 9, characterized in that the diameter constriction associated with the valve seat element (108) forms a radially inwardly directed step (58).
11. Valve device in accordance with Claim 9 or 10, characterized in that the valve seat element (108) comprises a recess (120) which surrounds the supporting surface (118) in the circumferential direction and in which a sealing element (116) is arranged.
12. Valve device in accordance with Claim 9, 10, or 11, characterized in that the valve seat element (108) comprises a through-opening (112) which adjoins the valve seat (110) in the flow direction (54) of the cleaning liquid, extends coaxially to a middle axis (115) of the valve seat element (108), and continuously expands in the flow direction (54) of the cleaning liquid in an end portion remote from the valve seat (110).
13. Valve device in accordance with Claim 12, characterized in that the diameter of the through-channel (30) in the region directly adjoining the valve seat element (108) in the flow direction (54) of the cleaning liquid is greater than the greatest diameter of the end portion of the through-opening (112) of the valve seat element (108).
14. Valve device in accordance with any one of the preceding Clams, characterized in that a spring holder (90) is fixed in the through-channel (30) upstream of the valve seat element (108) in relation to the flow direction (54) of the cleaning liquid, on which spring holder (90) the closing spring (124) is supported.
15. Valve device in accordance with Claim 14, characterized in that the spring holder (90) is pressed into a receiving portion (88) of the through-channel (30), wherein the valve seat element (108), the closing body (122), and the closing spring (124) are arranged in the receiving portion (88).
16. Valve device in accordance with Claim 15, characterized in that the receiving portion (88) is of rectilinear, cylindrical, and stepless configuration.
17. Valve device in accordance with Claim 14, 15, or 16, characterized in that the through-channel (30) comprises a diameter constriction associated with the spring holder (90), on which the spring holder (90) is supported.
18. Valve device in accordance with Claim 17, characterized in that the spring holder (90) comprises a supporting flange (92) which abuts against the diameter constriction associated with the spring holder (90).
19. Valve device in accordance with Claim 17 or 18, characterized in that the diameter constriction associated with the spring holder (90) is configured in the form of a radially inwardly directed step (56).
20. Valve device in accordance with any one of the preceding Claims, characterized in that a force-transmission element (128) is arranged between the closing spring (124) and the closing body (122).
21. Valve device in accordance with Claim 20, characterized in that the force-transmission element (128) consists of a non-ceramic material.
22. Valve device in accordance with Claim 20 or 21, characterized in that the force-transmission element (128) comprises a spring receiving portion (126) for accommodating an end region of the closing spring (124), which faces the force-transmission element (128), and a closing body receiving portion (130) for accommodating an end region of the closing body (122), which faces the force-transmission element (128).
23. Valve gun for a high-pressure cleaning appliance having a valve device (22) in accordance with any one of the preceding Claims and having a triggering lever (144) which is mechanically coupled to the valve plunger (132) and is mounted so as to be pivotable about a pivotal axis (146).

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