Patent Application
20220080448
The disclosure relates to a sealing element for sealing a transition between a spray gun body, in particular a paint spray gun body, and an attachment of a spray gun; an attachment, in particular a paint nozzle arrangement for a spray gun, in particular a paint spray gun; and a spray gun, in particular a paint spray gun.
According to the prior art, a spray gun, in particular a paint spray gun, in particular a compressed air-atomizing paint spray gun, has on its head a paint nozzle also referred to as a material nozzle, which is screwed into the gun body. At its front end, the paint nozzle often has a hollow cylindrical cone, from whose front opening the material being sprayed emerges during operation of the spray gun. However, the nozzle can also be designed to be conical at its front area. The gun head generally has an external thread via which an air nozzle ring with an air cap arranged therein is screwed onto the gun head. The air cap has a central opening whose diameter is greater than the outside diameter the paint nozzle cone or the outside diameter of the front end of a conical paint nozzle. The central opening of the air cap and the cone or the front end of the paint nozzle together form an annular gap. The so-called atomizer air emerges from this annular gap, generating a partial vacuum on the front surface of the paint nozzle in the nozzle arrangement just described so that the material being sprayed is sucked out of the paint nozzle. The material being atomized is fed to the atomizer air and torn into filaments and strips. Because of their hydrodynamic instability, the interaction between the rapidly flowing compressed air and the surrounding air and because of aerodynamic disturbances, these filaments and strips disintegrate into droplets that are blown away from the nozzle by the atomizing air.
The air cap also often has two horns, which are diametrically opposite each other and extend in the outflow direction beyond said annular gap and the paint outlet opening. Two supply holes, i.e. horn air supply channels, run from the back of the air cap to the horn air holes in the horns. Generally, each horn has at least one horn air hole, but preferably each horn has at least two horn air holes from which the horn air exits. The horn air holes are generally oriented so that they point in the direction of the longitudinal axis of the nozzle, beyond the annular gap in the output direction so that the so-called horn air emerging from the horn air holes can influence the air that has already emerged from the annular gap or the already at least partially formed paint jet or paint mist. The paint jet or also the spray jet with an originally circular cross section (round jet) is thereby compressed on its sides facing the horns and lengthened in a direction perpendicular thereto. A so-called broad jet is thus formed, which enables a greater surface painting speed. In addition to deforming the spray jet, the horn air is intended to further atomize the spray jet.
The aforementioned paint nozzle often has a paint nozzle seal. Such a paint nozzle seal is disclosed, for example, in DE 10 2018 118 737 A1. The paint nozzle seal 44 shown therein, in particular in
Such a paint nozzle arrangement has proven itself over many years. However, there is potential for improvement with respect to tightness and manufacturability. High tightness is desirable, since with deficient sealing, for example between the body and the paint nozzle, the material being sprayed could leave the transition between the body and the paint nozzle in an undesirable manner and reach the air-guiding area of the spray gun. This could lead to contamination of the air channels and air outlets of the spray gun and to an adverse effect on spray quality.
One aspect of the disclosure is therefore to provide a sealing element by means of which better sealing of a transition between a body of a spray and an attachment of a spray gun can be ensured and which is easier to manufacture.
Another aspect of the disclosure is to provide an attachment, in particular a paint nozzle arrangement, for a spray gun, in particular a paint spray gun, and a spray gun, in particular a paint spray gun in which a transition between an attachment and a body of a spray gun is better sealed.
The first aspect is achieved by a sealing element for sealing a transition between the body of a spray gun, in particular paint spray gun, and an attachment of a spray gun, in particular a paint nozzle, in which the sealing element is configured so that, when the attachment is arranged in the body, it forms an axially acting sealing surface and a radially acting sealing surface with the body and/or the attachment.
The attachment is preferably a paint nozzle or a paint nozzle arrangement, but can also be another attachment, like a fan control, a material amount regulator, an air micrometer, a compressed air connection or a material supply, like a paint container or a hose.
A paint nozzle arrangement can be understood to mean, for example, an arrangement of a, in particular one-piece, paint nozzle and at least one additional component, like a throttle, a disk, a sealing element, in particular a sealing element described in more detail below, and/or another component.
The body preferably has a grip area and an upper body with a head area and a suspension hook. The body is preferably designed in one piece, but can also be made up of several parts.
In the present case, an axially acting sealing surface is understood to mean that a surface of the sealing element rests sealingly against a counter-sealing surface, in which case the surface of the sealing element and the counter-sealing surface, in the present case a counter-sealing surface on the body of a spray gun, rest against each other, in particular are pressed against each other, in the axial direction, i.e. along a longitudinal axis of the sealing element.
In the present case, a radially acting sealing surface is understood to mean that a surface of the sealing element rests sealingly against a counter-sealing surface, in which case a surface on the inside and/or outside periphery of the sealing element and a counter-sealing surface on the inside and/or outside periphery of a component, in the present case on an inside and/or outside periphery in or on the body of a spray gun, rest against each other, in particular are pressed against each other, in the radial direction.
Due to the axially acting and radially acting sealing surface, the sealing element according to the disclosure provides a significantly improved sealing effect relative to sealing elements of the prior art. The material being sprayed would have to overcome two barriers in the form of sealing surfaces instead of only one, in order to leave the transition between the spray nozzle and the body of the spray gun in an undesirable manner and enter the air-guiding area of the spray gun. In addition, the material would also have to execute a change in direction, for example, from the radial direction to the axial direction. It is particularly advantageous that the axially acting sealing surface and the radially acting sealing surface are formed by the same sealing element. It is particularly advantageous that the axially acting sealing surface and the radially acting sealing surface are formed by the same sealing element. This means that a sealing element for radial sealing and an additional sealing element for axial sealing are not necessary, but that a single sealing element satisfies these objectives. The radial sealing surface and the axial sealing surface in the sealing element according to the disclosure can even be formed by the same part of the sealing element, for example, by a rear section of the sealing element configured as a hollow truncated cone, as described in more detail below, which simplifies manufacture of the sealing element. If necessary, of course, one or several additional sealing means can still be provided.
One advantage of expanding the sealing element to form a radial sealing surface, compared to the use of a sealing element introduced by force-fitting, lies in the fact that the expanding sealing element can be installed more easily and must satisfy less strict tolerance requirements than a sealing element introduced by force-fitting.
The second aspect is achieved by an attachment, in particular a paint nozzle arrangement for a spray gun, in particular a paint spray gun, in which there is at least one sealing element, as described in more detail above and below.
This attachment can also preferably be a paint nozzle or paint nozzle arrangement, but can also be another attachment, like a fan control, a material amount regulator, an air micrometer, a compressed air connection or a material supply, like a paint container or hose.
A paint nozzle arrangement can also be understood here to mean an arrangement of a, in particular one-piece, paint nozzle and at least one additional component, like a throttle, a disk, a sealing element, in particular a sealing element described in more detail below and/or another component.
The second aspect is also achieved by a spray gun, in particular paint spray gun, in which there is at least one sealing element described above and further below and/or an attachment described above and further below.
Comments concerning the sealing element according to the disclosure apply accordingly to the paint nozzle arrangement according to the disclosure and to the spray gun according to the disclosure.
Advantageous embodiments are also disclosed herein.
The sealing element is preferably configured so that when the attachment is arranged in the body, in particular when fastened therein, it expands at at least one end and thereby forms the radially acting sealing surface with the body and/or the attachment.
The attachment, in particular the paint nozzle or the paint nozzle arrangement, can be screwed into the body, for example. The sealing element can begin to expand from the beginning of the arrangement process, in particular at the beginning of screwing the attachment into the body, but preferably only expands toward the end of the arrangement process, in particular toward the end of screwing-in, i.e., when the attachment is tightened in the body. Expansion in the present case is understood to mean enlargement of a periphery and/or a diameter of the sealing element, preferably a part of the sealing element, with particular preference an end of the sealing element, in particular by material expansion. The sealing element preferably expands in the tightened state, preferably reversibly. In the untightened state, when the attachment is not arranged in the body of the spray gun, the sealing element does not expand and has a first outside diameter or outside periphery. If the attachment is fastened in the gun body, expansion occurs and the sealing element is present in its tightened state. In this state, at least part of the sealing element, in particular one end of the sealing element, has a second outside diameter or outside periphery that is greater than the first outside diameter or outside periphery. The second outside diameter or outside periphery is preferably the maximum outside diameter or outside periphery of the sealing element, i.e., the sealing element in no instance has a greater outside diameter or outside periphery than in the expanded state. Upon release and/or loosening, the sealing element ideally recovers its unexpanded state and the formerly expanded part of the sealing element again has the first outside diameter or outside periphery. In reality, a slight residual deformation of the expanded part can occur, i.e., the outside diameter or outside periphery of the previously expanded part of the sealing element may be somewhat larger than the first outside diameter or outside periphery before the first tightening of the sealing element, but will be much smaller than the second outside diameter or outside periphery of the expanded part of the sealing element.
The sealing element preferably has a front section with at least one device for arrangement of the sealing element on an attachment, in particular a snap-in tab, in particular a circumferential snap-in tab, and a rear section, the rear section being designed as a truncated hollow cone.
The sealing element can be designed essentially as a hollow cylinder, i.e., in the form of a sleeve. In the present case, the front section is understood to mean the side of the sealing element facing the paint nozzle, in particular the paint outlet opening of the paint nozzle. The sealing element has the above-mentioned snap-in tab or at least a preferably circumferential hook on this front section, preferably on its outer periphery, by means of which the sealing element can be arranged on the paint nozzle, preferably releasably. These snap-in tabs can engage an undercut on the inside periphery of the paint nozzle. The sealing element, however, can also have a preferably circumferential groove, with which a protrusion on the inside periphery of the paint nozzle can engage. Naturally, the paint nozzle can have the snap-in tab and the sealing element can have the undercut or the paint nozzle can have the groove and the sealing element the protrusion. Other types of connection are also conceivable, for example, a screw connection or also a permanent connection, such as an adhesive bond. However, a releasable connection is preferred in order to permit replacement of the sealing element when worn.
In the present case, the rear section is understood to mean the side of the sealing element facing away from the paint nozzle, in particular the paint outlet opening of the paint nozzle. This section is preferably designed as a truncated hollow cone, i.e., the section widens rearward. With particular preference, the rear section or the rear part of the rear section is the expanding part of the sealing element.
A substantially cylindrical section can be arranged between the front and rear section of the sealing element. This can have a preferably circumferential collar on its outer peripheral surface, which can function as a stopper for positioning the sealing element on the paint nozzle.
The sealing element preferably consists at least partially of a flexible material, in particular plastic or a plastic mixture, preferably HDPE. In particular, the part of the sealing element forming an axially acting sealing surface and a radially acting sealing surface should consist of a flexible material, in particular plastic or a plastic mixture, preferably HDPE, in order to ensure the functionality of the sealing element, in which case said part of the sealing element expands sufficiently. The sealing element is preferably made entirely of such a material.
The attachment according to the disclosure, which is preferably a paint nozzle arrangement, also preferably has at least a front end with a paint outlet opening, a rear end with a paint inlet opening and a substantially hollow cylindrical section in between, in which the sealing element at least in some areas has essentially the same inside diameter as the substantially hollow cylindrical section. A particularly undisturbed flow of the material being sprayed form the sealing element into the substantially hollow cylindrical section of the paint nozzle is thereby possible. With particular preference, the sealing element at least in some areas has essentially the same inside diameter as a paint channel located behind the sealing element in the body of the spray gun, which enables an unimpeded flow of the material being sprayed from the paint channel into the sealing element. Stages in which paint collects, dries up, and could adversely affect the material flow and material quality, in particular the material purity, can also thereby be avoided.
The spray gun according to the disclosure preferably also has at least one body, in which the body has at least one area for accommodating an attachment, in particular a paint nozzle and/or a paint nozzle arrangement, the area having at least one essentially cylindrical wall section, in particular a wall section having at least partially a thread, preferably an internal thread, with a shoulder arranged on one end of the wall section, in particular a circumferentially configured shoulder.
By means of the thread on the essentially cylindrical wall section in the body, the paint nozzle arrangement, which has a thread corresponding to this thread [on the essentially cylindrical wall section], and which can consist in particular of a paint nozzle and the sealing element according to the disclosure, can be screwed into the body of the spray gun. Since the outside diameter or outside periphery of the sealing element is at most as large as the inside diameter of the cylindrical wall section, but preferably somewhat smaller, the sealing element and the cylindrical wall section do not initially touch or at most slightly brush against each other. Toward the end of the screwing-in process, the rear end of the rear section of the sealing element touches the shoulder arranged on one end of the wall section, which is preferably configured circumferentially. If the paint nozzle arrangement is further screwed into the body, in particular tightened, the rear section is forced increasingly more strongly against the shoulder so that the axially acting sealing surface is formed between the sealing element and the body. Owing to the special configuration of this part of the sealing element, in particular the configuration as a truncated hollow cone, the part is widened, i.e., expands. The outside diameter or outside periphery of this part of the sealing element becomes larger until it is forced increasingly more strongly against the cylindrical wall section in the body, with which it was scarcely in contact at the beginning of the screwing-in process. The radially acting sealing surface is thus formed between the sealing element and the body. As already described above, the fact that both an axially acting sealing surface and a radially acting sealing surface are present reduces the risk that the material being sprayed from the paint channel in the body of the spray gun will flow between the body and the paint nozzle and into the air-guiding area of the spray gun.
As already mentioned, an inside diameter of the area for accommodating an attachment, in particular an inside diameter of the essentially cylindrical wall section, is with particular preference at least in some areas greater than or equal to an outside diameter of the sealing element. As a result, an easier arrangement is possible, in particular screwing-in the paint and nozzle arrangement with the sealing element into the area for accommodating an attachment, since very little or no friction resistance need be overcome between the sealing element and the cylindrical wall section of the receiving area. Furthermore, wear of the sealing element, which in the case of a larger outside diameter of the sealing element would result from friction of the sealing element on the cylindrical wall section, can also be avoided.
As already described above, the sealing element is preferably arranged between the body and the attachment and, when the attachment is arranged in the body, forms a radially acting sealing surface with the wall section and an axially acting sealing surface with the shoulder.
With particular preference, the spray gun has a stop for an attachment, which also defines the maximum expansion of a sealing element. The stop for an attachment means in particular a stop that forms a stop for insertion, in particular screwing, of the attachment into the body. For example, a surface of the attachment can encounter a stop in the gun body or a thread end forms the stop. When an ongoing arrangement process, for example, continued screwing-in of a paint nozzle arrangement into the body of a spray gun, entails an increasingly greater expansion of a sealing element, the maximum expansion of the sealing element can be defined via the stop for the attachment. If the attachment can no longer be further introduced, in particular screwed into the body, the sealing element in this case also cannot further expand.
In all cases the sealing element can also naturally be arranged in or on the gun body and the attachment pressed onto the sealing element in or on the gun body, thereby forming the axially acting sealing surface and the radially acting sealing surface.
The disclosure is explained in more detail below, by way of example and with reference to six figures. In the figures:
The sealing element 44 in the screwed-in paint nozzle arrangement 24 is pressed against a counter-sealing surface 84 and seals off the material-guiding area of the spray gun 1, in particular the transition area between the paint channel in the body 2 and the hollow section of the paint nozzle 40 for passage of the material being sprayed relative to the air-guiding area of the spray gun 1. The sealing element 44 then forms only an axially acting sealing surface with the body 2, namely against the counter-sealing surface 84.
The sealing element 440 has a device on the front section for arrangement of the sealing element 440 on a paint nozzle 40, which in the present case can be the same paint nozzle 40 as the paint nozzle 40 shown in the previous figures, and the device for arrangement of the sealing element 440 in the present case is configured as a circumferential snap-in tab 442. An essentially cylindrical section located between the front and rear section of the sealing element 440 has a circumferential collar 443, which in the present case functions as a stop for positioning the sealing element 440 on the point nozzle 40. The sealing element 440 also has a rear section configured as a truncated hollow cone 441.
The inside diameter of the essentially cylindrical center section of the sealing element 440 and the inside diameter of the front section of the sealing element 440 are essentially the same as the inside diameter of the hollow cylindrical section 402 of the paint nozzle 40. A particularly undisturbed flow of the material being sprayed from the sealing element 440 into the essentially hollow cylindrical section 402 of the paint nozzle 40 is thus possible.
An area for accommodating an attachment for a body 20, in the present case the paint nozzle arrangement 240 of
The inside diameter of the essentially cylindrical middle section of the sealing element 440 is essentially the same as the inside diameter of the paint channel 201 located upstream of the sealing element 440. As a result, in addition to the above-described undisturbed flow of the material being sprayed from sealing element 440 into the essentially hollow cylindrical section 402 of the paint nozzle 40, a particularly undisturbed flow of the material being sprayed from the paint channel 201 into the sealing element 440 is also possible. In addition, stages in which paint accumulates, dries out and can adversely affect the material flow and material quality, in particular the material purity, can thus be avoided.
The inside diameter of the essentially cylindrical wall section 50 in the present illustrative embodiment is somewhat larger than the outside diameter of the unexpanded sealing element 440 at its largest location. As already mentioned above, an easier arrangement is thereby possible, in particular screwing-in the paint nozzle arrangement 240 with the sealing element 440 into the body 20, since very little or no friction resistance need be overcome between the sealing element 440 and the cylindrical wall section 50. Wear of the sealing element 440, which in the case of a larger outside diameter of sealing element 440 would result from friction of the sealing element 440 on the cylindrical wall section 50, can also be avoided.
Apart from the sealing element 440, the components shown in
The above illustrative embodiment describes only a limited selection of possible implementations and therefore does not represent a restriction of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102020123769.3 | Sep 2020 | DE | national |
