EP4029649A1 - Device for treating a surface of a workpiece with a blasting agent - Google Patents

Abstract

The invention relates to a device for treating a surface of a workpiece with a blasting agent, comprising: a blasting room (1) with a blasting device (2) for accelerating the blasting agent onto the workpiece held in the blasting room (1), a first one leading away from the blasting room (1). Dust removal line (4a) for removing dust, an air sifting device (10) for separating dust and a fine fraction of the blasting agent, a second dust removal line (4b) leading away from the wind safety device (10) for removing the dust and the fine fraction of the blasting agent, one downstream of the main bunker (12) arranged downstream of the air sifting device (10) for receiving the blasting agent, a dosing bunker (13) connected to the main bunker (10) for replenishing unused blasting agent, a blasting agent supply line (15 ) for supplying the blasting medium to the blasting device (2).To increase the efficiency of the Vo According to the invention, it is proposed that at least one first measuring device (11) for measuring the wind speed or a parameter corresponding to the wind speed is provided in the second dust removal line (4b).

Description

The invention relates to a device for treating a surface of a workpiece with a blasting agent according to the preamble of patent claim 1.

Such a device is, for example, from WO 2018/065220 A1 known.

In the known device, the fill level in the main bunker is measured. As soon as the fill level falls below a specified level, unused blasting media is automatically refilled from a dosing bunker into the main bunker. From the subsequent quantities of unused blasting agent, an average blasting agent consumption of the device can be deduced. An operating time in the range of 48 to 96 hours is usually observed to determine the average consumption of abrasive. The efficiency of the device can be deduced from the average blasting agent consumption. For example, the average blasting agent consumption changes when a blasting agent acceleration device, for example a turbine, is worn out, or the blasting agent throughput on a turbine changes due to mechanical conditions.

According to the state of the art, the average abrasive consumption is always calculated retrospectively. Determining the average blasting abrasive consumption is therefore time-consuming and very imprecise in relation to short periods of time.

The object of the invention is to eliminate the disadvantages of the prior art. In particular, a device for treating a surface of a workpiece is to be specified, which can be operated with improved efficiency.

This object is solved by the features of patent claim 1. Expedient refinements of the invention result from the dependent patent claims.

According to the invention, it is proposed that at least one first measuring device for measuring the wind speed or a parameter corresponding to the wind speed is provided in the second dust removal line.

Surprisingly, it turned out that by measuring the wind speed or a parameter corresponding to the wind speed, a statement can be made about how efficiently the device works. The statement obtained advantageously enables a conclusion to be drawn about the current operating state of the device, i. H. any faults can be detected in real time or before they have a negative impact.

Within the meaning of the present invention, “a parameter corresponding to the wind speed” is understood to mean a parameter which is physically related to the wind speed. This can be, for example, a mass flow, a volume flow, a particle flow or the like.

According to an advantageous embodiment, the first measuring device includes a Prandtl probe and/or a hot-wire sensor and/or a laser Doppler anemometer.

The wind speed can be recorded reliably and with little wear, particularly with a Prandtl probe.

According to a further embodiment, the proposed first measuring device is a component of a wind speed or a corresponding one

Parameters regulating control circuit. The proposed control circuit always enables a largely complete separation of a fine fraction of the blasting agent or a so-called "undersize". The efficiency of the device can thus be improved in a particularly simple manner.

According to a further embodiment, a second measuring device is provided for measuring a current consumption of the blasting device. Instead of the current consumption, a corresponding parameter can also be measured, from which the current consumption can be inferred. From the measured power consumption, conclusions can be drawn about wear or a malfunction of the blasting device.

According to a further advantageous embodiment, the dosing bunker includes a new grain feed device for replenishing unused blasting agent to the main bunker. The new grain feed device expediently comprises a line connecting the dosing bunker to the main bunker. The line can, for example, connect the dosing bunker to a blasting agent return line, through which blasting agent is removed from the blasting room and fed to the air classification device. A bucket elevator can also be provided instead of the line. A snail may be provided in the conduit.

According to a further embodiment, the new grain feed device can comprise a valve and a valve control device for controlling the opening times of the valve. This makes it possible to supply the main bunker with a predetermined amount of unused blasting media. By controlling the opening times of the valve, a predetermined volume or mass of unused blasting media can be fed to the main bunker.

The valve can be a slide, a perforated plate that can be closed with a closure plate, a funnel with a closure body, or other valve devices suitable for replenishing the blasting agent.

Such a valve device or such a valve is expediently connected to the line. In particular, it can be switched into the line.

Furthermore, a third measuring device can be provided for measuring a weight and/or volume of the blasting agent located in the dosing bunker. Instead of the weight or the volume, another parameter can also be measured from which the weight and/or volume of blasting agent in the dosing bunker can be deduced, e.g. B. a fill level or the like. The first measuring device and / or the second measuring device and / or the third measuring device are expediently connected or can be connected to a computer for the transmission of measured values. This makes it possible to display the measured values supplied by the measuring devices individually or optionally in combination, for example over time on a screen. From the measured values displayed over time, a user can immediately identify faults and initiate countermeasures. This makes it possible to always operate the device efficiently.

• G_n das in einem vorgegebenen Zeitintervall aus den Dosierbunker nachgesetzte Gewicht an Strahlmittel, und
• T_s die Strahldauer im vorgegebenen Zeitintervall ist.

The computer can be set up to determine an average abrasive consumption V _m according to the following formula: V _m = G _n /T _s ,
whereby

• G _n is the weight of blasting agent added from the dosing bunker in a specified time interval, and
• T _s is the beam duration in the given time interval.

If, for example, a predetermined volume of unused blasting agent is added by controlling the opening times of a valve, this volume can be converted into the added weight G _n to determine the average blasting agent consumption V _m . In this case, the respective volume must be multiplied by a bulk density of the blasting agent used.

The average blasting agent consumption V _m can also be displayed as an additional measured value over time, either individually or in combination with the aforementioned measured values. This provides the user with further information on how efficiently the device is operating.

The computer is expediently set up to display at least two of the following measured values in a time-correlated manner: wind speed, power consumption, weight, average blasting medium consumption V _m . Instead of the aforementioned measured values, a corresponding parameter can also be displayed. In particular, the proposed temporally correlated display of the measured values or the corresponding parameters enables faults to be recognized quickly and thus efficient operation to be maintained.

According to a further embodiment, a device for separating a dust fraction and/or a fine fraction of the blasting agent is provided. The blasting room is connected to the device for separating the dust fraction and/or the fine fraction of the blasting agent via a first dust removal line, a T-piece and a third dust removal line. A first flow control valve can be switched on in the first dust removal line. The air sifting device can be connected to the device for separating the dust fraction and/or the fine fraction of the blasting agent via a second dust removal line, the T-piece and the third dust removal line. A second flow control valve can be switched into the second dust removal line. By controlling the flow valve or valves, a volume or mass flow into the device for separating the dust fraction and/or a fine fraction of the blasting agent can be controlled. This makes it possible to influence the separation rate of the dust fraction and/or the fine fraction of the abrasive. The at least one flow control valve can be controlled or also regulated by means of the control loop.

Fig. 1

Ein Blockschaltbild einer Vorrichtung,

Fig. 2

Erste Messwerte zum mittleren Strahlmittelverbrauch und der Windgeschwindigkeit über der Zeit,

Fig. 3

Zweite Messwerte zum mittleren Strahlmittelverbrauch und der Windgeschwindigkeit über der Zeit, und

Fig. 4

Dritte Messwerte zur Stromstärke und der Windgeschwindigkeit über der Zeit.

Advantageous configurations of the invention are explained in more detail below with reference to the drawings. Show it:

1

A block diagram of a device,

2

First measured values for the average consumption of abrasive and the wind speed over time,

3

Second measured values for mean abrasive consumption and wind speed over time, and

4

Third readings of amperage and wind speed over time.

1 shows a block diagram of a device according to the invention. A blasting room 1 is provided here with two blasting devices 2 for accelerating a blasting agent against a workpiece (not shown here) held in the blasting room 1 . A blasting agent return line for removing used blasting agent from the blasting room 1 is designated by the reference number 3 . The blasting agent return line 3 opens into an air sifting device 10. A first dust removal line leading away from the blasting chamber 1 is designated by the reference number 4a. A first flow control valve 6a is connected upstream of a T-piece 5 in the first dust removal line 4a. Reference numeral 7 designates a dedusting system provided downstream of the T-piece 5 . The T-piece 5 is connected to the dedusting system 7 via a third dust removal line 8 . A chimney 9 is located downstream of the dedusting system 7. A first measuring device 11 for measuring the wind speed or a parameter corresponding thereto is provided in a suction or second dust removal line 4b leading away from the wind sifting device 10. The first measuring device 11 can be a Prandtl probe, for example. The second dust removal line 4b can also open into the T-piece 5. A second flow control valve 6b can be switched on in the second dust removal line 4b.

Numeral 12 designates a main bunker provided downstream of the wind classifier 10 . Reference number 13 designates a dosing bunker, which is connected to the blasting agent return line 3 by means of a new grit feed device 14 for replenishing unused blasting agent new grit into the main bunker 12 . The new grain feed device 14 can be, for example, a line, a chute or a pneumatic conveying device.

The new grain feed device can include a valve 14a, which can be controlled with a valve control device 14b for controlling the opening times of the valve (likewise not shown here). The valve may be on-line or connected to the line, chute or pneumatic conveyor. By controlling the opening times of the valve, it is possible to feed the main bunker 12 with a predetermined volume of unused blast media.

The reference number 15 designates a schematically indicated blasting medium supply line for supplying blasting medium to the blasting device 2 .

The reference number 16 designates a second measuring device or current measuring device for measuring the current consumption of the blasting device 2.

Reference number 17 designates a third measuring device or weight measuring device, for example a weight load cell, for measuring the weight of the dosing bunker 13.

The function of the device is as follows:
The blasting agent is fed from the main bunker 12 to the blasting device 2 via the blasting agent supply lines 15 . The blasting agent is accelerated onto a workpiece (not shown here) by means of the blasting device 2 . It will Workpiece superficially worn away. Part of the abrasive is destroyed and forms a fine fraction of abrasive and dust. The used blasting agent is withdrawn from the blasting room 1 via the blasting agent return line 3 and fed to the wind sifting device 10 . In particular, a dust fraction and/or a fine blasting agent fraction are separated by means of the wind sifting device 10 . The remaining fraction of the blasting agent is in turn fed from the wind sifting device 10 to the main bunker 12 arranged downstream.

A fill level in the main bunker 12 is constantly monitored by means of a fill level sensor (not shown here). As soon as the fill level falls below a predetermined level, unused blasting agent is fed from the dosing bunker 13 to the main bunker 12 via the new grain feed device 14, preferably via the blasting agent return line 3, until the predetermined level is reached again. As a result, the weight of the dosing bunker 13 decreases. The change in the weight of the dosing bunker 13 is z. B. measured by the weight measuring device 17 and registered by means of a computer (not shown here) over time. Instead of the weight of the dosing bunker 13, a volume of unused blasting agent removed from the dosing bunker 13 can also be determined. The volume can be determined via a measurement or via the opening times of the valve used in each case. In the case of an observation of the volume of subsequently added blasting media, this can be converted into a corresponding weight.

A wind speed or a parameter corresponding thereto is measured using the first measuring device 11 . The wind speed or the corresponding parameter is also recorded and registered over time by the computer.

Furthermore, the current consumption of the blasting device 2 is measured by means of the current measuring device 16 . The measured values are in turn recorded and registered by the computer.

the Figures 2 to 4 show registered readings over time.

2 shows the first measured values for the average consumption of abrasive over time and the wind speed over time. Both the average abrasive consumption and the suction speed hardly change in the example shown. The device works efficiently.

3 shows second measured values for average abrasive consumption and wind speed, each over time. In the second example shown, the average abrasive consumption increases over time. The initially strong increase in the mean abrasive consumption is due to excessive wind speed. After the wind speed was reduced by the user around the time "12:00", the average abrasive consumption increases more slowly.

It has been shown that a method carried out with the device runs correctly under given boundary conditions if the wind speed has a specific correlation in relation to the mean consumption of blasting media. Expediently, a corresponding mean consumption of blasting agent is registered for different wind speeds if the method is running properly. A disruption can be recognized by the fact that, at a given wind speed, a currently observed mean consumption of blasting media deviates from the registered mean consumption of blasting media.

The boundary conditions mentioned above can be the following parameters: type of system, type of blasting agent, particle size distribution of the blasting agent and the like.

In order to be able to recognize a fault quickly and easily, in addition to the currently measured average blasting agent consumption, the registered average blasting agent consumption can be displayed in the graphic, which was previously used for a proper execution of the procedure for the respective wind speeds has been determined.

At the in 4 The third measured values shown are the amperage of the jet device and the wind speed, each shown over time. In the marked section, the amperage or power consumption of the blasting device is zero. At the same time, the wind speed of the wind sifting device remains at the original high level. In the third example shown here, the unnecessary operation of the wind sifting device could have been avoided to improve efficiency.

Reference List

1

blast room

2

blasting device

3

Abrasive return line

4a

first dust discharge line

4b

second dust discharge line

5

tee

6a

first flow valve

6b

second flow valve

7

dedusting system

8th

third dust discharge line

9

Chimney

10

wind sifting device

11

first measuring device

12

main bunker

13

dosing bunker

14

New grain feed device

14a

Valve

14b

valve control device

15

Abrasive supply line

16

current measuring device (second measuring device)

17

Weight measuring device (third measuring device)

Claims (14)

Device for treating a surface of a workpiece with a blasting medium, comprising: a blasting room (1) with a blasting device (2) for accelerating the blasting medium onto the workpiece accommodated in the blasting room (1), a first dust removal line (4a) leading away from the blasting chamber (1) for removing dust, an air sifting device (10) for separating dust and a fine fraction of blasting agent, a second dust removal line (4b) leading away from the wind safety device (10) for removing the dust and the fine fraction of the blasting agent, a main bunker (12) downstream of the wind sifting device (10) for receiving the blasting medium, a metering bunker (13) connected to the main bunker (12) for replenishing unused blasting media, a blasting medium supply line (15) connecting the main bunker (12) to the blasting device (2) for supplying the blasting medium to the blasting device (2), characterized in that at least one first measuring device (11) for measuring the wind speed or a parameter corresponding to the wind speed is provided in the second dust discharge line (4b). Device according to Claim 1, in which the first measuring device (11) comprises a Prandtl probe and/or a hot-wire sensor and/or a laser Doppler anemometer. Device according to one of the preceding claims, in which the first measuring device (10) is part of a control loop which regulates the wind speed or a parameter corresponding thereto. Device according to one of the preceding claims, wherein a second measuring device (17) is provided for measuring a current consumption of the jet device (2) or a parameter corresponding thereto. Device according to one of the preceding claims, wherein a new grain feed device (14) is provided for replenishing a predetermined quantity of unused blasting agent from the dosing bunker (13) to the main bunker (12). Device according to one of the preceding claims, wherein the new grain feed device (14) comprises a line connecting the dosing bunker (13) to the main bunker (12). Device according to one of the preceding claims, wherein the new grain feed device (14) comprises a valve (14a) and a valve control device (14b) for controlling the opening times of the valve (14a). Apparatus according to any preceding claim, wherein the valve (14a) is connected to the conduit. Device according to one of the preceding claims, wherein a third measuring device (16) is provided for measuring a weight and/or a volume of the blasting agent located in the dosing bunker (13). Device according to one of the preceding claims, wherein the first measuring device (11) and/or the second measuring device (16) and/or the third measuring device (17) is or can be connected to a computer for the transmission of measured values. Apparatus according to any one of the preceding claims, wherein the computer is arranged to determine an average abrasive consumption V _m according to the following formula: V _m = G _n /T _s , whereby G _n is the weight of blasting media added from the dosing bunker (13) at a predetermined time interval, and T _s is the beam duration in the given time interval. Device according to one of the preceding claims, wherein the computer is set up for the time-correlated display of at least two of the following measured values or one parameter corresponding thereto: wind speed, power consumption, weight G _n , average blasting agent consumption V _m . Device according to one of the preceding claims, wherein a device (7) for separating the dust and/or the fine fraction of the blasting agent is provided, which is connected by means of a T-piece (5) to the first (4a) and second dust removal line (4b) associated third dust discharge line (8) is connected. Device according to one of the preceding claims, wherein a further computer, in particular a mobile phone, with which the computer can be connected via the Internet for the transmission of the measured values and/or the time-correlated display.

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