EP1384554A1 - Sand blasting device - Google Patents

Abstract

The mixing chamber (30) for particles and air lies below the centrifugal rotor (2) axis in the operational position of the blasting unit (1). The introduction channel slants up towards the axis from below, into the rotor chamber (22). The compressed air is blasted into the mixing chamber, essentially in the direction of the introduction channel (31). The introduction channel section (31') inside the casing is slightly curved such that its free end terminates just ahead of the radially inner edge of the rotor blades.

Description

The present invention relates to a jet device for the machining of workpiece surfaces by means of a granular blasting medium, with a drivable, um an axis of rotation rotatable impeller with centrifugal blades, with a blast wheel housing surrounding the blast wheel with a blast media ejection port, with, a Blasting medium supply line for the supply of the blasting medium, with one in front of the blast wheel in the area of one Blasting medium-air mixing chamber in the blasting medium supply line einmündenden compressed air supply line and with a s.den Mixing chamber subsequent. Introductory channel for the Blasting medium-air mixture, whose inner end is inside the spinner radially inward of the spinner blades lies and in the radial direction of the spinner has.

A jet device of the type mentioned is from the US-PS 6,126,516 known. In this known jet device the longitudinal direction of the blasting medium-air mixing chamber runs substantially coaxial with the axis of rotation the blower wheel. The blasting medium supply leads from coming up at an oblique angle into the mixing chamber one. The compressed air supply also runs approximately coaxial with the axis of rotation of the blast wheel and true in its longitudinal direction with the longitudinal direction of the mixing chamber match. In the center of the blast wheel is a deflecting body arranged within which the in the Mixing chamber produced blasting agent-air mixture a deflection experiences about 90 °. This will be the from the Mixing chamber initially in a direction parallel to the Rotary axis of the blast wheel moving abrasive-air mixture deflected by 90 ° and in the radial direction of the Blower wheel in the spaces between the Skimming blades transferred.

A disadvantage is in this known jet device considered that in the center of the blast wheel within the deflection arranged there a sharp deflection of blasting medium-air mixture with a small Curve radius is done. This sharp diversion will the surface of the deflecting body, in particular on the outer side of the deflection curve, heavily loaded and in the ongoing operation of the blasting device severely worn. Therefore, it is necessary here to achieve at least sufficient service life a particularly hard material to use for the deflecting body. As a result, the Production of the deflection by high material costs and high processing costs more expensive, reflecting the overall cost the jet device noticeably breaks through. In addition, there is a further disadvantage of the known jet device in that through the deflecting the jet center-air mixture in the axial direction of the blast wheel seen is not evenly distributed. Rather, it comes it means that a larger proportion of the blasting agent in Axial direction of the spinner seen in the area passes, which faces away from the blasting agent supply lies. This effect is caused by the sharp Deflection of the blasting agent-air mixture acting strong centrifugal forces, in particular the heavier abrasive particles towards the outside of the bend to move the diversion. This will cause an uneven Spray pattern on the workpiece to be machined causes what is not wanted. In addition, will the spreader blades in the axial direction of the spinner wheel Seen unevenly and accordingly worn unevenly, so that here is no optimal Service life of the centrifugal blades is achieved. Finally, it should be mentioned as a disadvantage that the known Radiation device an external compressed air supply needed for their operation.

For the present invention, the task arises a jet device of the type mentioned above create that avoids the disadvantages listed and in particular a heavily loaded deflecting body in the center of the blast wheel is no longer needed, in which the spinner blades of the spinner wheel uniform subjected to the blasting agent-air mixture and optionally also without external compressed air supply is operational.

• daß die Strahlmittel-Luft-Mischkammer in Betriebslage der Strahleinrichtung unterhalb der Drehachse des Schleuderrades liegt,
• daß der Einführungskanal schräg zur Drehachse von unten nach oben in das Schleuderradgehäuse geführt ist,
• daß die Druckluft in einer im wesentlichen in Richtung des Einführungskanals weisenden Richtung in die Mischkammer einblasbar ist und
• daß der im Inneren des Schleuderradgehäuses liegende Teil des Einführungskanals bis zu seinem freien Ende eine solche flache Krümmung aufweist, daß das freie Ende in Radialrichtung der Schleuderschaufeln weisend unmittelbar vor deren radial innerer Kante endet.

The object is achieved according to the invention with a jet device of the type mentioned, which is characterized

• that the blasting medium-air mixing chamber is in the operating position of the blasting device below the axis of rotation of the blast wheel,
• that the introduction channel is guided obliquely to the axis of rotation from bottom to top in the Raduderradgehäuse,
• in that the compressed air can be injected into the mixing chamber in a direction pointing essentially in the direction of the introduction channel, and
• in that the part of the introduction channel lying in the interior of the blasting wheel housing has such a flat curvature up to its free end that the free end ends in the radial direction of the spinning blades, pointing directly in front of its radially inner edge.

Due to the specified arrangement and design of said Components of the jet device will be advantageous achieved that a sharp deflection of the blasting agent-air mixture not in the center of the spinner more occurs. Rather, the blasting agent-air mixture in only a relatively small amount from the radial direction of the blast wheel deviating direction obliquely from below transported upwards into the center of the blast wheel. Finally, there is only a slight deflection the blasting medium-air mixture required to this in the radial direction of the spinner in this be reconciled. This only occurs in the introduction channel still a relatively small amount of wear on the production of the introduction channel of a less wear-resistant Material allowed or much higher Service life when using highly wear-resistant material leads. The desired and for the promotion of Blasting medium-air mixture advantageous fluidization of the mixture is in the jet device according to the invention achieved with high reliability and good effect, so that also a high and uniform abrasive flow rate and thus high performance the jet device are guaranteed. As for the feeder of blasting medium-air mixture into the interstices between the centrifugal blades only a flat Curvature in the region of the introduction channel go through will also affect the centrifugal forces on the Blasting agent particles barely, thereby achieving the desired uniform application of the centrifugal blades with the blasting agent and thus the desired uniform Blast image achieved on a workpiece to be machined become.

Preferably, it is further provided that the longitudinal direction of the leading into the blower wheel housing part of the introduction channel to the axis of rotation of the impeller one Angle α forms between about 30 and 60 °. Within the Introductory channel must then until the transfer of the blasting medium-air mixture at the blower wheel the mixture only still deflected by the residual angle, which remains up to 90 ° become. The larger the angle α, the smaller is the remaining required diversion. The maximum size of the angle α is technically limited by the free diameter in the center of the impeller between the radially inner edges of the centrifugal blades and the diameter of the introduction channel, which is a particular one Minimum size may not be lower.

As a particularly favorable compromise between the different Requirements has in practice an angle α exposed by about 45 °.

Next is for the jet device according to the invention provided that in the direction of the axis of rotation of the spinner seen the introduction channel in an angular range from ± 45 ° to the vertical direction upwards or obliquely to goes up. By selecting a specific angle within the specified angle range becomes the range set in the circumferential direction of the blast wheel, within which the transfer of the blasting medium-air mixture in the spaces between the centrifugal blades he follows. In this way can be also determine over which circumferential angle range the blasting medium-air mixture accelerated within the blast wheel is before the blasting medium is ejected. This allows the beam effect and the spray pattern different requirements of different applications to adjust.

To facilitate this mentioned adaptation is further provided that the introduction channel by means of a detachable Flange connection with the blower wheel housing or with a surrounding outer housing of the jet device connected is. The detachable flange connection offers the possibility of the introduction channel against a another introduction channel with a different angular position replace or the same insertion channel in one another angular position again with the rest of the jet device connect to. In this way, at least one graded change of said angle possible.

An even finer setting of said angle can be achieved in that the flange as rotatable and fixable in desired Verdrehstellungen Flange is formed. That way is one virtually stepless adjustment of the desired angle and its determination possible. In addition, so at Demand from the operator of the jet device with the least Cost of the angle individually depending on the application new be adjusted to always get the best possible beam result to achieve.

A further embodiment of the jet device according to Invention is characterized in that for blowing the compressed air into the mixing chamber at least one in provided a wall of the mixing chamber built-in nozzle is. By using this nozzle becomes a special achieved high exit velocity of the compressed air, the a particularly intensive fluidization of the blasting agent caused by generating the jet center-air mixture. Preferably, the nozzle is also damaged or Wear easily replaceable.

To the fluidization of the abrasive in the field of Mixing chamber and the introduction of the blasting agent-air mixture through the introduction channel into the blast wheel to be able to influence, the invention further proposes that the axial position of the nozzle in the wall of the Mixing chamber and / or the discharge direction of the nozzle relative adjustable to the longitudinal direction of the introduction channel and can be fixed in desired positions.

To the jet device according to the invention optionally also without being able to operate an external compressed air supply, proposes an embodiment of the jet device, that this has a drive motor through which the Impeller is rotatably driven, that by the same drive motor at the same time a compressor wheel of a part the jet device forming air compressor rotatably drivable is and that a compressed air line from an output of the air compressor to the blasting medium supply line merging compressed air supply line is guided. By the part of the jet forming air compressor the jet device is independent of one external compressed air supply. At the same time, the for the drive of the blast wheel existing drive motor also for the drive of the compressor wheel of the air compressor used. Thus, the jet device only needs a single drive motor, even if in addition equipped with the air compressor.

In a first embodiment of the jet device with Air compressor is further provided that an output shaft the drive motor at a first end of the Drive motor led out of this and with the Impeller, the front of the first end of the drive motor is arranged, connected and that the same or a second output shaft of the drive motor on a second front end of the drive motor led out of this and with the compressor wheel of the air compressor, arranged in front of the second front end of the drive motor is connected. With this execution becomes a particularly clear arrangement of the individual components reaches the blasting device, with a disassembly and assembly on the one hand of the impeller and on the other of the air compressor in each case as a result of spatial separation is easily possible.

See an alternative embodiment in this regard in that the air compressor is transverse to the axis of rotation of the drive motor offset added to the rest of the jet device is and that the compressor wheel of the air compressor rotatably driven by a drive gear from the drive motor is. This embodiment of the jet device has the particular advantage that the air compressor with a deviating from the speed of the impeller Speed is operable. In particular, hereby is the Possibility created the compressor wheel of the air compressor at a higher speed than the spinner drive.

The mentioned transmission gear is preferably a belt transmission or a gear transmission. The belt transmission has the advantage of a simple construction and a most maintenance free. The gear transmission offers the special advantage that within a given Space higher translations can be achieved.

The drive motor of the jet device is preferably a Electric motor, preferably with variable speed. The Jet device then needed for their drive motor only an electrical power supply, for example 220 or 380 volts AC from a public Supply network. By varying the speed of the Drive motor can increase the speed of the blast wheel and optionally the compressor wheel of the air compressor to be influenced. This change in the speed causes at the same time a change in the beam effect of the jet device.

Further measures to influence the function and effect the jet device consist in that the air compressor and / or in the course of the compressed air line at least an adjustable organ for influencing Pressure and / or amount of introduced into the mixing chamber Compressed air is provided.

Another measure for influencing function and Effect of the jet device according to the invention exists Finally, that in the Strahlmittelzuleitung for the supply of the blasting medium to the mixing chamber at least an adjustable organ for influencing the pro Time unit introduced into the mixing chamber amount of Blasting agent is provided.

Figur 1

eine Strahleinrichtung in einer ersten Ausführung in einem Längsschnitt, teils in Seitenansicht,

Figur 2

die Strahleinrichtung aus Figur 1 in einer Stirnansicht gemäß der Blickrichtung II in Figur 1, und

Figur 3

die Strahleinrichtung in zwei geänderten Ausführungen in Seitenansicht.

In the following, embodiments of the jet device according to the invention will be explained. The figures of the drawing show:

FIG. 1

a jet device in a first embodiment in a longitudinal section, partly in side view,

FIG. 2

the jet device of Figure 1 in an end view according to the viewing direction II in Figure 1, and

FIG. 3

the jet device in two modified versions in side view.

As the figure 1 of the drawing shows, this has here illustrated first embodiment of a jet device 1 a blast wheel 2 inside a Impeller housing 22 rotatably mounted about a rotation axis 24 is. On the outside, the blower wheel housing 22 surrounded by an outer housing 10. The outer housing 10 comprises a base plate 11, two left and right of Impeller 2 and the Bluderradgehäuse 22 lying End walls 12, 12 'and a peripheral wall thirteenth

Left in front of the left end wall 12 is a Strahlmittelzuleitung 3, here the shape of an upward down open pipe socket has. At this the blasting medium supply line 3 forming pipe socket can become another Supply line or a storage hopper or an allocation device for the abrasive to be added, as is usual with relevant jet devices is. Downwards, the blasting medium supply line 3 goes in a blasting agent-air mixing chamber 30 via. This mixing chamber is well below the axis of rotation 24 about Half the height of the radius of the spinner 2.

In a wall of the mixing chamber 30, a nozzle 4 is inserted, for blowing compressed air into the mixing chamber 30 serves. When viewed in the blowing direction of the nozzle 4 closes an introduction channel 31 to the mixing chamber 30, by the blasting agent-air mixture produced by means of the compressed air diagonally from bottom to top in the center of the impeller 2 is feasible.

The mixing chamber 30 is well below the axis of rotation 24 of the impeller 2 and accordingly runs the Introductory channel 31 of the mixing chamber 30 obliquely at the top into the interior of the outer housing 10, the blower wheel housing 22 and the spinner 2 itself. The upper End region 31 'of the introduction channel 31 lies in the Inside of the blast wheel 2. The blast wheel 2 is off a flat base plate 20 and a plurality of attached thereto, Radially pointing centrifugal blades 21 formed. The upper end portion 31 'of the introduction channel 31 terminates immediately before the radially inner edges 21 'of the centrifugal blades 21 and points there in the radial direction of the blast wheel 2.

In the operation of the jet device 1 is by the blasting medium supply line 3 a blasting agent, e.g. small steel wheels Glass balls, led into the mixing chamber 30. By the Nozzle 4, compressed air is injected into the mixing chamber 30, causing fluidization of the blasting agent through Formation of a blasting medium-air mixture comes. This Blasting medium-air mixture is made by the compressed air the nozzle 4 through the introduction channel 31 obliquely upward promoted. In this case, the introduction channel 31 forms with the Rotary axis 24 of the centrifugal wheel 2 in the present example an angle α of about 45 °. In the inside of the Impeller 2 lying end portion 31 'of the introduction channel 31 is a gentle deflection of the blasting agent-air mixture by about 45 °, so that ultimately the blasting agent-air mixture in the radial direction in the Gaps between the centrifugal blades 21 of the Blower wheel 2 passes. By rotation of the blower wheel 2, the blasting agent in the circumferential direction of Blower wheel 2 accelerates and down through one pointing blast media ejection opening 23 on a not here represented, to be machined by blasting workpiece ejected.

As Figure 1 further shows, in the present example the jet device 1, the introduction channel 31 in the left end wall 12 of the outer housing 10 by means of a Flange 32 is supported. This flange 32 is as rotatable and fixable in desired Verdrehstellungen Flange formed. In this way, the Direction of the introduction channel 31 relative to the vertical direction be adjusted. This adjustment is later illustrated and described with reference to FIG 2.

To drive the impeller 2 here is an electric motor 5, by means of a flange 51 with the Outer housing 10, here the right end wall 12 ', connected is. A led out to the left from the drive motor 5 Output shaft 52 is rotationally fixed to the Impeller 2, here with the base disk 20, connected.

Furthermore, the embodiment shown in Figure 1 includes the jet device 1 an air compressor. 6 This air compressor 6 is opposite to the impeller 2 Flanged front end of the drive motor 5. For this purpose, a second flange connection is at this point 55 provided. The drive of a in the air compressor. 6 rotatably mounted, not visible here compressor wheel via a second output shaft 56, the after right out of the drive motor 5 is led out and the rotationally fixed there with the compressor wheel of the air compressor 6 is connected. This drives the drive motor 5, which is preferably a variable speed electric motor is, at the same time and at the same speed both the blast wheel 2 and the air compressor 6 at.

An output 64 of the air compressor 6 is here via one only shown as a dotted line compressed air line connected to a compressed air supply line 40, in turn is connected to the nozzle 4. This will be the for required the fluidization of the blasting medium-air mixture Compressed air generated within the jet device 1 and an external compressed air supply is not required.

FIG. 2 of the drawing shows the jet device 1 Figure 1 in front view according to the viewing direction II in FIG 1. In the center of Figure 2 is the blasting medium supply line 3 with the down to this subsequent Mixing chamber 30 recognizable. The nozzle 4 with its compressed air supply line 40 is here for clarity not shown. Starting from the mixing chamber 30 extends upwards and into the interior of the outer housing 10 in the introduction channel 31. The introduction channel 31 is, as previously mentioned, by means of a rotatable and fixable in desired Verdrehstellungen Flanged connection 32 facing the viewer End wall 12 of the outer housing 10 is connected. hereby there is the possibility of the introduction channel 31 in one Angle range of about ± 45 ° to Vertikalrichtüng 33 too adjust. The two extreme twist positions are additionally shown by dashed lines in Figure 2.

As Figure 2 illustrates, arrive depending on the respective adjusted rotational position of the introduction channel 31 relative to the vertical direction 33, the particles of Blasting agent in different positions in the Impeller 2. Accordingly, the circumferential angle, over which the blasting agent from the blast wheel. 2 is accelerated, different sizes. It is this Circumferential angle the greater, the more the introduction channel 31 is rotated counterclockwise to the left, and the smaller, the more the introduction channel 31 after Turned right clockwise.

The discharge of the blasting agent takes place downwards by the there in the base plate 11 recessed abrasive ejection opening 23. The coverable beam area on the surface of a workpiece, not shown here is through a bunch of dotted beam arrows illustrated.

FIG. 3 of the drawing shows two in a side view possible modifications of the jet device 1 according to the FIG. 1

The arrangement of blast wheel 2, outer housing 10, Blasting medium supply line 3, blasting medium-air mixing chamber 30, nozzle 4, compressed air supply line 40 and drive motor 5 corresponds to the jet device 1 according to Figure 3 the previously described embodiment according to FIG. 1

It is different that the air compressor 6 not now more arranged on the right front end of the drive motor 5 is, but to two of them, optional possible positions.

A first position in which the air compressor 6 alternatively can be arranged over the left side of the Drive motor 5, as shown in dashed lines there is. The drive of belonging to the air compressor 6, invisible compressor wheel takes place here over a transmission gear 65, which is a belt transmission with two V-belts is. The output shaft 52 of the drive motor 5, which is connected to the blast wheel 2, points here additionally one or more pulleys, which together with a rotationally connected to the fan second pulley and on the pulleys guided V-belt form the transmission gear 65.

Alternatively, the air compressor 6 above the right Half of the drive motor 5 may be arranged as there also indicated in dashed lines. The drive the fan of the air compressor 6 takes place here in the example shown also via a belt transmission trained transmission gear 65th

The output 64 of the air compressor 6 is in each case again via a compressed air line 41 with the compressed air supply line 40 and the nozzle 4 connected. Due to the transmission gear 65 may be the air compressor 6, more precisely Fan wheel, to be driven at a speed that deviates from the speed of the impeller 2. expedient is in particular a drive of the fan wheel at a speed greater than the speed of the 2. Impeller in this way will be sufficient Quantity and a sufficiently high pressure of the compressed air for the production of the blasting medium-air mixture in the Mixing chamber 30 provided so that an external Compressed air supply is not necessary. At the same time comes also the jet device 1 in their versions according to Figure 3 with a single drive motor 5 from.

Claims (15)

A blasting device (1) for machining workpiece surfaces by means of a granular blasting medium, comprising a drivable blast wheel (2) with spinning blades (21) rotatable about an axis of rotation (24) with a blast wheel housing (22) surrounding the blast wheel (2) with a blast media ejection opening (23), with a Strahlmittelzuleitung (3) for the supply of the blasting agent, with a front of the blast wheel (2) in the region of a blasting medium-air mixing chamber (30) in the blasting agent supply line (3) opening into the compressed air supply line (40) and with a the mixing chamber (30) subsequent introduction channel (31) for the blasting medium-air mixture, the inner end of the inside of the impeller (2) radially inwardly of the centrifugal blades (21) and points in the radial direction of the impeller (2),
characterized, that the blasting agent and air mixing chamber (30) located in the operating position of the jet device (1) below the axis of rotation (24) of the impeller (2), that the introduction channel (31) is guided obliquely to the axis of rotation (24) from bottom to top in the blower wheel housing (22), in that the compressed air can be blown into the mixing chamber (30) in a direction pointing essentially in the direction of the introduction channel (31), and that the lying inside the Schleuderradgehäuses (22) part of the introduction passage 'up to its free end has such a shallow curvature, that the free end in the radial direction of the blasting blades (21) pointing immediately before their radially inner edge (21 (31)') ends. A blasting device according to claim 1, characterized in that the longitudinal direction of the part of the introduction channel (31) leading into the blast wheel housing (22) forms an angle α between about 30 and 60 ° with respect to the axis of rotation (24) of the blast wheel (2). Radiation device according to claim 2, characterized in that the angle α is about 45 °. Radiation device according to one of the preceding claims, characterized in that viewed in the direction of the axis of rotation (24) of the centrifugal wheel (2) seen the insertion channel (31) in an angular range of ± 45 ° to the vertical direction (33) upwards or obliquely upwards. A jet device according to claim 4, characterized in that the introduction channel (31) is connected to the blast wheel housing (22) by means of a detachable flange connection (32) or to a surrounding outer housing (10) of the blasting device (1). Radiation device according to claim 5, characterized in that the flange connection (32) is designed as a rotatable and fixable in desired rotational positions flange. Radiation device according to one of the preceding claims, characterized in that at least one nozzle (4) built into a wall of the mixing chamber (30) is provided for blowing in the compressed air into the mixing chamber (30). A jet device according to claim 7, characterized in that the axial position of the nozzle (4) in the wall of the mixing chamber (30) and / or the discharge direction of the nozzle (4) relative to the longitudinal direction of the introduction channel (31) is adjustable and fixable in desired positions , Beam device according to any one of the preceding claims, characterized in that it comprises a drive motor (5) is driven in rotation by the impeller (2), that by the same drive motor (5) at the same time a compressor wheel of a part of the abrasive blasting device (1) forming the air compressor ( 6) is rotatably drivable and that a compressed air line (41) from an output (64) of the air compressor (6) to the in the Strahlmittelzuleitung (3) opens out compressed air supply line (40) is guided. A blasting device according to claim 9, characterized in that an output shaft (52) of the drive motor (5) at a first end of the drive motor (5) led out of this and with the impeller (2) arranged in front of the first end face of the drive motor (5) is connected, and that the same or a second output shaft (56) of the drive motor (5) at a second front end of the drive motor (5) led out of this and with the compressor wheel of the air compressor (6), in front of the second front end of the drive motor (5 ) is connected. Radiation device according to claim 9, characterized in that the air compressor (6) is mounted transversely to the rotation axis of the drive motor (5) offset to the rest of the jet device (1) and that the compressor wheel of the air compressor (6) via a transmission gear (65) from the drive motor (5) is rotary drivable. A jet device according to claim 11, characterized in that the transmission gear is a belt transmission or a gear transmission. Radiation device according to one of claims 9 to 12, characterized in that the drive motor (5) is an electric motor, preferably with variable speed. Radiation device according to one of Claims 9 to 13, characterized in that at least one adjustable element for influencing the pressure and / or quantity of the compressed air introduced into the mixing chamber (30) is provided on the air compressor (6) and / or in the course of the compressed air line (41) is. Radiation device according to one of the preceding claims, characterized in that at least one adjustable element for influencing the quantity of the blasting medium introduced into the mixing chamber (30) per unit of time is provided in the blasting agent supply line (3) for supplying the blasting medium to the mixing chamber (30).

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