Electrostatic powder coating gun.

The invention relates to an electrostatic powder-Beschich processing pistol according to the preamble of claim 1.

Electrostatic powder coating guns with this Basic construction have long been known and in different Embodiments in the market.

In these known coating guns is generally the powder-air mixture through the handle or adjacent to the supplied handle, in which case the powder duct through the entire Length of the gun barrel is performed. The high-voltage generator is seated parallel to the powder duct, whether in or on the handle or in or on the gun barrel. However, this results in the Powder-air mixture within the gun a long flow away, so that for the powder promotional air, a high pressure is required to the flow resistance in the gun to overcome. In addition, results from the flow of long powder channel, a comparatively high wear parts by abrasion. Finally, the juxtaposition of leads Powder channel and high-voltage generator to the fact that either the Handle or the pistol barrel comparatively large dimensio must be defined.

Object of the present invention is to provide an electrostatic to provide powder-coating gun, wherein the Stromungsweg of the powder-air mixture within the gun is comparatively short, so that flow resistance and abrasion are reduced, and their handle and pistol tube slim can be designed. The solution of this object, from the characterizing features of claim 1.

In powder-coating gun according to the invention is thus the powder duct very short and requires only the frontmost Area of ​​the gun barrel. The formation of the powder duct as a torus with itself followed it diffuser tube piece arising beyond particularly favorable flow Behaves results. The result of these actions is that with a comparatively manage as low pressure of the conveying air and abrasion on the channel wall is extremely low. The space in the gun tube behind the powder duct is fully high voltage generator for Available, so that the gun barrel formed very slim can be; the same is true if it is a hand gun These, for the pistol grip. In addition, the surface of the Walls, on which the powder can be deposited, reduced and the Tangentialstromung with oblique appointing the deposition of powder additionally minimized.

A particularly advantageous development of the invention is in Claim 2 in. Here, the high voltage is producers of compressed air flows around, so as not to static Boots comes, and this purge air is then used to yet Keeping the electrode of powder deposits.

In the drawing embodiments of the invention are Example as illustrated. It shows

<b>Fig.</b> 1 is a longitudinal section through the front region of the Powder-coating gun,

<b>Fig.</b> 2 is a cross section along the line II-II of <b>Fig.</b> 1 and

<b>Fig.</b> 3 is a partial longitudinal section of a modification, the Powder-coating gun of <b>Fig.</b> 1.

The in <b>Fig.</b> 1 illustrated front portion of the gun barrel <b>10</b> Electrostatic powder-coating gun according to the Invention consists of the barrel main body <b>10</b>A and on its Mouth part screwed Run extension <b>10</b>b. Of the Running main part <b>10</b>a is at its mouth end by the Overflow pipe-piece lid wall <b>12</b> completed, the cover wall <b>12</b> a central bore <b>12</b>A has, in the one according to forward projecting electrode support tube <b>13</b> is inserted tightly. in the Running main part is located centrally, a high voltage generator <b>14</b>Whose outer diameter is slightly smaller than the Inner diameter of the tubular barrel main body <b>10</b>a, in such a way that an annular gap <b>15</b> remains free. The high-voltage generator<b>14</b> has spacer feet <b>14</b>a to that ensure that between Front end of the high-voltage generator <b>14</b> and top panel <b>12</b> on gap <b>16</b> remains free on the one hand with the annular space <b>15</b> and on the other hand with the interior <b>13</b>a of the electrode support tube <b>13</b> is in open communication.

The run-extension <b>10</b>b has substantially the form of a Cylinder whose rear part than the run-main part <b>10</b>a cross pipe section is formed; it has this Pipe section has an internal thread that allows the barrel extension <b>10</b>b on the external thread of the barrel main body <b>10</b>a screwed is. Furthermore, the run-extension<b>10</b>b a central Inner bore, through which the electrode-holder tube <b>13</b> after is forward guided axially. In the central region of the Run extension <b>10</b>b is in this one the electrode carrier tube <b>13</b> concentrically surrounding torus powder channel <b>17</b> cut, the in forward direction in a ring-powder channel <b>18</b> continues, the under diffuser-like enlargement at the front end of the extension <b>10</b>b opens to the outside. In the Torus powder channel <b>17</b> opens tangentially and with bias in employment Forward direction one inlet connection <b>19</b>To which a not lined feeding tube for the powder-air mixture to closable.

Before the mouth of the electrode support tube <b>13</b> is a located baffle <b>20</b> with protruding forward needle electrode <b>21</b>. wherein the baffle <b>20</b> by transverse pins in Electrode support tube <b>13</b> is supported. In baffles<b>20</b> extend to electrode <b>21</b> parallel air channels <b>22</b>, Which with the interior of Electrode support tube <b>13</b> keep in touch. electrode<b>21</b> itself is a high voltage cable <b>23</b>Which by the Interior of the electrode carrier tube <b>13</b> is guided through, with the high voltage output of the voltage generator <b>14</b> connected. With <b>24</b> finally, is a on the front region of the Run extension <b>10</b>b plugged orifice ring called.

The powder-coating gun operates as follows. On the not-drawn delivery tube is a Powder-air mixture in the direction of arrow B through the connector <b>19</b> through spirally-tangentially into the toroidal powder duct <b>17</b> initiated, by which the mixture in the annular channel <b>18</b> reaches and flows therethrough to the outside. By diffuser like expansion of the annular channel <b>18</b> and the effect of impact body <b>20</b> is a very early rising powder cloud produced what both the charging and the transport of Powder favored. The charging of the powder is carried out by the electrode <b>21</b>Which, as mentioned, is indeed at high voltage. From non-subscribed rear portion of the coating gun ago is supplied as scavenging air pressure, in the direction of the Arrows A. This purge air passes through the annular gap <b>15</b> and arrives over the end gap <b>16</b> and the interior of the electrode carrier tube <b>13</b> in the channels <b>22</b>That it as fine, the electrode <b>21</b> surrounding air jets leaving. This air wash system keeps the area the column <b>15</b>. <b>16</b> for the discharge of static charges and in Area of ​​the electrode <b>21</b> for their pollution.

<b>Fig.</b> 3 shows a modification, for achieving a Powder-flat jet. In this case, compared with the embodiment of<b>Fig.</b> 1 of the orifice ring used therein <b>24</b> by a cap <b>30</b> With slit <b>31</b> replaced by which the electrode needle <b>21</b> protrudes. Of course, in this embodiment also the impact body <b>20</b> omitted. Especially with this off is the lead shape of the interior of the electrode support tube <b>13</b> emerging and the electrode needle <b>21</b> compressed air flowing around of great importance, because this not only a contami tion of the electrode needle, but also clogging of the die slot <b>31</b> prevented.

The illustrated embodiments, numerous Abwandlun gen out without departing from the scope of the invention. So is it is of course not mandatory, that the gun barrel <b>10</b> of two mutually separable parts, namely the Bulk <b>10</b>a and the extension <b>10</b>b, is; against a However, one-piece gun barrel resulting from the Darge presented division of the advantages of easier production and above all the easier separation and purification of Pistol. Also, the annular channel<b>18</b> over its entire length have constant diameter, even towards the mouth narrow. Finally it should be noted that the high-voltage producer <b>14</b> Also, only the final stage (cascade) of producers may be circuit.