CZ5638U1 - Air exhaustion device - Google Patents

Abstract

An operating device contains a binary flow sensor (SE) that generates a binary sensor signal (BS) when the speed (V) of the exhaust air flow (LS) in the exhaust air equipment (AA) falls below or exceeds a lower threshold value (Vmin). A programme-controlled computer (SPS) influences controllable or adjustable operating means of the exhaust air equipment depending on said sensor signal, for example closing flaps (VS1, VS2, VS3) or a ventilating unit (AG) with an adjustable speed of rotation, so that the speed (V) of the exhaust air flow (LS) does not fall below the lower threshold value (Vmin). The flow sensor (SE) preferably has a rotary lock (R) which closes (P1) an exhaust air collecting pipe (AR) when no exhaust air flow (AB) is present and is automatically held open (P2) by a flow of exhaust air (LS). A binary sensor element (B), preferably a proximity switch, generates a binary sensor signal (BS) when the rotary lock (R) enters the sensor detection range.

Description

The invention relates to an air exhaust device comprising an exhaust air collection tube with connected exhaust ports of machine tools, a ventilation unit for generating an exhaust air flow, and operating means for influencing the exhaust air flow rate.

BACKGROUND OF THE INVENTION

Extraction equipment used for ventilation of craft or industrial production facilities must in many cases extract air that is more or less contaminated by particulate matter. Thus, e.g. For woodworking or stone processing, heavy cutting of wood chips or sawdust may occur in machine tools. of dust. Such clouds of particulate matter particles must be sucked out, as far as possible at the place of origin, by means of an air extraction device, especially for reasons of labor protection (eg Technical Rules for Hazardous Materials).

Z pat. GB 2 136 560 A discloses an exhaust air device for enclosed spaces or air ducts. chambers, in particular for multiple outlet boxes. In this case, it may be the case that the pressure in the exhaust air manifold drops sharply due to the connection of several suction boxes. This condition is detected by a pressure sensor. As a result, the speed of the ventilation unit is reduced in order to avoid excessive energy consumption of the ventilation unit and, on the other hand, to undesirably cool the outlet boxes.

Finally, pat. CA 1 273 524 discloses an air exhaust device having a safety switch for evaluating the exhaust air flow, which switches off the ventilation unit in the case of insufficient intake air flow.

In order to maintain the functional capability of the air extraction device, the speed of the exhaust air flow within the device must not fall below a certain minimum value. Otherwise there would be a risk of dirt accumulating inside the device. Furthermore, the transport performance could be affected due to the reduction of the cross-section, and in the worst case, clogging could occur so that the necessary exhaust of the contaminated air of the machine tools could not be ensured. For example, in accordance with the Technical Regulations for Hazardous Areas in Air Extraction Plants, it is necessary to provide for the removal of wood dust or dust. wood sawdust (p. 553), the lowest air speed> 20 m / sec for dry sawdust and> 30 m / sec for wet sawdust.

The problem is that the correct measurement of the analogue actual value of the exhaust air flow velocity, e.g. elsewhere in the pipe system of the air suction device is not possible for various reasons as a rule. The sensor integrated into the guide tube system would become unnecessary and costly after a short period of operation due to contamination or even mechanical damage

-1GB 5638 Ul Not Applicable. Furthermore, both the installation costs and the maintenance costs for the removal of air equipment equipped with a high-quality functional exhaust air velocity measuring device could be so high that the construction and operation of such a device would become particularly small or small. medium-sized craft and industrial plants under heavy load.

On the other hand, it is the task of the technical solution to design a simple and structurally robust and possibly retrofitly retrofit operating air extraction device, which can also be maintained in advance at a given minimum value for the current velocity without direct online detection of the analog actual instantaneous flow rate. exhaust air.

The essence of the technical solution

This object is solved in the air suction device according to the invention in that it comprises a binary minimum flow sensor which is arranged in the exhaust air collection tube and a software-controlled computer, in particular with a memory programmable controller, which has one input for supplying a binary sensor signal a minimum flow rate sensor and which is connected at one outlet to means for influencing the flow rate of the exhaust air flow, wherein the ventilation unit for generating the exhaust air flow is provided with speed control.

Advantageous developments of the technical solution are set forth in the subclaims.

Overview of the drawings

The invention and its preferred embodiments will be explained in more detail below with reference to the drawings.

FIG. 1 is a block diagram for an exemplary industrial manufacturing facility equipped with an air exhaust device.

FIG. 2 is a cross-sectional view of a first preferred embodiment for a binary minimum flow sensor in an operating device according to the present invention;

FIG. 3 is a cross-sectional view of a second preferred embodiment for a binary minimum flow sensor in an operating device according to the invention.

FIG. 4 is an exterior view of a binary sensor element for the embodiment of FIG. 3.

FIG. 5 shows a possible sequence of binary sensor signals at the output of the binary sensor of the minimum flow value of the process device according to the invention, with additional signal filtering.

-2GB 5638 Ul

Examples of technical solution

For example, the industrial production equipment shown in the block diagram of FIG. 1 has three BM1 machine tools. BM2. BM3. These may be, for example, planers, saws or saw blades. grinding machines in woodworking operation. Under certain circumstances, they emit clouds of particulate matter, which must be sucked out at the point of origin, especially in order to protect work.

An air suction device is provided for this purpose. According to the block diagram in FIG. 1 it consists, for example, of suction nozzles AB1. AB2. AB3. which are directly assigned to the respective machine tool. The suction nozzles open into the exhaust air collecting pipe AR, in which the exhaust air stream LS, formed by the solids particles, is created by the ventilation unit AG. It has a velocity V and is discharged via the outlet throat AS at the end of the exhaust air collecting tube AR, serving as an air outlet LE to the ambient atmosphere. Finally, the air suction device has controllable operating means, whereby the value of the velocity V of the exhaust air flow LS in the exhaust air collection tube AR is influenced.

In the embodiment shown in the block diagram of FIG. 1, electrically controllable shutter valves VSI are provided as operating means. VS2. VS3 for suction nozzles AB1, AB2, AB3. These are preferably arranged on the side of their suction end and can close when the respective machine tool is disconnected. By closing or opening the individual shutter flaps VSI. VS2, VS3 at the ends of the AB1 suction nozzles. AB2, AB3, the suction power of the air suction device at adjacent suction nozzles as well as the total value of the flow velocity V of the suction air stream LS can be easily influenced. As a further controllable operating means for influencing the instantaneous velocity value V of the exhaust air flow LS, the air suction device in the exhaust air collection tube AR of FIG.

The air suction device according to the invention comprises a binary sensor SE with minimum flow values. This sends a binary sensor signal BS when the flow rate V of the exhaust air flow LS falls below or exceeds a predetermined limit value Vmin. In the block diagram of FIG. 1, such a minimum flow rate binary sensor SE is arranged, for example, in the outlet throat AS at the end of the exhaust air collecting tube AR. The instantaneous lower limit value Vmin of the velocity V of the exhaust air flow LS is preferably preset from outside. The minimum flow rate binary sensor SE sends a binary sensor signal BS via the ML line.

This binary sensor signal BS is supplied to a program-controlled PSP, which is another essential element of the invention. In a program-controlled SPS computer, a low power range control and memory programmable control may be advantageous. The software-controlled SPS computer affects the controllable operating means of the air extractor by influencing the instantaneous value of the binary sensor signal BS on the ML signal line.

The speed V of the current flow LS does not fall below the predetermined lower limit value Vmin.

In the embodiment of FIG. 1, the SPS computer is connected to the electrically controllable shutter VSI via a control signal SL line. VS2, VS3 on the suction end side of the suction nozzles AB1, AB2. AB3. In the example of FIG. 1, the SPS computer is connected via a further SM measurement signal line to the AG speed control unit.

For further explanation, it is assumed that in the example of FIG. 1, the machine tools BM1, BM2 are in operation and thus the electrically controllable shutter VSI. VS2 suction nozzles AB1, AB2 open. On the other hand, it is assumed that the machine tool BM3 is disconnected and the shutter VS3 is closed at the respective suction branch AB3. If, in this operating state, the minimum flow rate binary sensor SE is detected by the binary sensor signal BS a drop in the flow rate V of the exhaust air flow LS below the permissible lower limit value Vmin, the controllable operating means are activated. In the example of FIG. 1, for example, the shut-off flap VS3 at the suction branch AB3 of a BM3 machine tool which is not in operation can be opened by means of a control signal SL. If this measure alone is not sufficient to increase the flow velocity V of the exhaust air flow LS so that it exceeds a predetermined lower limit value Vmin, in the example of FIG. 1, the SPS computer can increase the speed of the ventilation unit AG via SM measurement signals. .

Giant. 2 shows in cross-section a first preferred embodiment of the binary sensor SE of the minimum flow value. It has a swinging flap R, which is connected to the rotary shaft DP in the exhaust air collecting tube AR, and is arranged such that in the absence of the exhaust air flow LS the exhaust air collecting tube AR is closed in almost all cross section and air is automatically opened and kept open. Accordingly, FIG. 2 shows the starting position P1 of the swinging flap R almost completely enclosing the exhaust air collecting tube AR and the operating position P2 in which the swinging flap R held by the exhaust air flow LS in the open state is shown.

A stable initial position PI at a flow velocity of approximately 0 m / sec can be achieved either by the inherent weight of the swiveling flap R or by means of a return spring with low tractive force. In the embodiment according to FIG. 2, the swinging flap R by means of a rotary shaft DP is arranged in a separate storage box K in the region of the exhaust air outlet LE of the collecting tube AR. At the outlet of the exhaust air flow LS, the rocker lever R is swiveled from the initial position P1, and each swiveling stage of the rocker valve R can be associated with a certain value of the flow velocity V.

According to the technical solution, the binary sensor SE has minimum flow values of the binary sensor element B, which transmits the binary sensor signal BS when the rocker flap R in the open position P2 enters or exits the sensor sensed area. By means of additional adjustment means, a binary sensor can be used

Adjust element B so that the swinging flap R held in the open position P2 then enters or exits the sensor-sensed area if the exhaust air flow velocity LS exceeds or falls below a predetermined lower limit value Vmin. drops.

In the example according to FIG. 2, the binary sensor element B of the binary sensor SE of the minimum flow value is, for example, an inductive proximity switch or a light barrier embedded in the wall of the housing K containing a swiveling flap R. the exhaust air collector pipe AR, or in the storage box K arranged in the collector pipe AR. With sufficient swiveling to the operating position P2, i.e. at a sufficiently high velocity V of the exhaust air flow LS, the swiveling flap R approaches so close to the binary sensor element B that the entire sensor-sensed area is encompassed and the SPS computer is activated. the level of the binary sensor signal BS on the ML measurement signal line. Adjustment of the binary sensor element B, ie tuning its initiation threshold to the lowest suction air flow velocity LS, for example> 20 m / sec, is performed in the example of FIG. 2 by changing the screw-in depth of the binary sensor element B into the wall of the housing K containing a swinging flap R .

The adjustment of the binary sensor element B is preferably carried out when commissioning the process device, for example by measuring the flow velocity with an enometer and detecting the respective positions of the swinging flap R. Preferably, the swinging flap R has an angle at flow rates> 20 m / sec. a pivot greater than 70 ° to the starting position. By means of an aenometer, the binary sensor element B in the primary sensor SE of the minimum flow value can be easily adjusted so that the swinging flap R, reaching the lower limit value Vmin of the exhaust air flow rate LS, enters the area sensed by the binary sensor element B. during the commissioning of the air suction device, the suction air stream LS is still not loaded with solids. Finally, in the example of FIG. 2, a stop AN is provided to limit the opening angle of the swinging flap R, which also serves to mechanically protect the binary sensor element B protruding into the interior of the storage box K.

Giant. 3, 4 show a second preferred embodiment of the binary sensor SE of the minimum flow value. 3 shows the swinging flap R, which is made in the same manner as in the example of FIG. 2. In contrast, however, in the second embodiment, seen from the outside of FIG. 4, a binary sensor element B of the binary sensor is arranged. In this embodiment, there is provided a signaling device which is rigidly connected to the rotary shaft DP of the swinging damper R and whose one end, connected to the signaling device, is led out through the storage wall. Skříně K.

In the example of FIG. 4, the signaling device consists of a signal rod ST which is connected to a swinging flap R by means of a rotary shaft DP, which is led out through the wall of the housing K via one end. The same movement as the swivel flap R is located therein, so that the degree of opening can be sensed in the same way as in the embodiment of FIG. 2. The free end of the signal rod ST is free. which is not connected to the protruding end of the rotary shaft DP, provided with a flag F which, when entering the area sensed by the binary sensor element B, causes a defined activation of the active signal level of the binary sensor signal BS. Advantageously, the flag F is extended in the closing direction of the swinging flap R. According to another embodiment, shown in Fig. 4, the binary sensor element B is displaceably mounted on an adjusting arch JB mounted on the outside of the storage box K. element B of the sensing area with instantaneous deflection of the swinging flap R and the corresponding signal bars ST. Oscillations of the swinging flap R, which can be caused, for example, by the impact of larger particles of solid matter, can be captured by mechanical damping of the swinging flap R, or made ineffective by filtering the binary sensor signals BS. For this purpose, in the diagram of FIG. 1, a filter device L, for example a timer having an adjustable filter time TF, is arranged in the ML signal line between the binary sensor SE of the minimum flow value and the program-controlled SPS computer. see Fig. 6. The FL filter device can also be integrated into the software of a PLC programmed computer. The filter device FL delays at least one alternation of the binary sensor signal S with the active signal level, which indicates that the instantaneous flow velocity V has exceeded the lower limit value Vmin. An inactive signal level indicates that the instantaneous flow velocity V has fallen below the lower limit value Vmin.

FIG. 5 shows an exemplary waveform of binary sensor signals. In this case, the signal level at time S1 changes, for example, from inactive signal level 0 to the active signal level

Thus, the swinging flap R has entered the sensing area of the binary sensor element B, again indicating that the current flow rate has exceeded the lower limit value Vmin in the desired manner. At time S2, the exhaust air flow velocity LS falls again below the lower limit value Vmin. so that the binary sensor signal BS drops from active to inactive signal level 0. FIG. 5 also shows the waveform of the binary sensor signal BS occurring at the output of the filtering device FL. It can be seen that signal 1 changes to 0 at time S2 only after the filter time TF has elapsed.

At time point S3, the binary sensor signal BS acquires the active signal level Ia for a short period of time. At that time, at time point S4, it returns to the inactive signal level 0. During the intermediate filtered binary sensor signal BS, it can be recognized that the transition from inactive to the active signal level level at time point S3 is further passed unfiltered, while a new drop to the inactive signal level only appears at time point S4 after the filter time TF has elapsed. This function of the filter device has the advantage that transient deflections caused, for example, by the impact of solid particles on the swinging flap R can be suppressed during the binary sensor signal BS. This can be clearly seen on the right edge of FIG. 5. In FIG. 5, successive transitions KP in the manner of oscillations between the levels of the binary sensor signal BS are shown for a short time. These oscillations are not reflected in the filtered binary sensor-BS 5638 UI signal that keeps the active signal level 1 unchanged. Then, the filtered binary sensor signal BS follows at time S5 by transitioning the filtered binary sensor signal BS from inactive to the active signal level. Immediately thereafter, at time S6, the decrease to the inactive level becomes during the filtering time TF into an asset level signal. This remains ineffective since the binary sensor signal BS in Fig. 5 again changes to the active level at the time S7 before the filtering time TF has elapsed.

As a result, there are no controllable and controllable FL filter devices, no disturbing short-term connections of the exhaust air device operating means by the programmed SPS computer,

It is particularly advantageous to use the minimum flow value of FIG. 4 as a swinging flap R to form the binary sensor SE, in many cases arranged in the area of the exhaust air outlet LE at the end of the exhaust air collecting pipe AR. The device thus allows a continuous control of the flow rate V of the exhaust air flow LS, whether the lower limit value Vmin is observed. simple and robust technical solution. The plant can be built at low cost, or it can also be equipped with existing air exhaust systems without much cost.

Claims (11)

PROTECTION REQUIREMENTS An air extractor comprising an air intake manifold with connected extractor nozzles of machine tools, a ventilator for generating an intake air flow, and operating means for influencing the exhaust air flow rate, characterized in that it comprises a minimum value binary sensor (SE) a flow which is arranged in the exhaust air collection tube (AR) and a programmable computer (SPS), in particular with a memory programmable controller, which has one input for supplying a binary sensor (BS) binary sensor (SE) minimum flow rate and at one outlet connected to operating means for influencing the flow rate (V) of the exhaust air flow (LS). Suction device according to claim 2, characterized in that the ventilation unit (AG) for producing the exhaust air flow (LS) is provided with speed control. Extraction device according to claim 1, characterized in that it comprises, as operating means, electrically controllable shut-off flaps (VS1, VS2, VS3), which are arranged in the extraction necks (AB1, AB2, AB3) of machine tools (BM1, BM2, BM3). ). -7GB 5638 U1 Suction device according to one of the preceding claims 1 to 4, characterized in that the minimum flow rate binary sensor (SE) consists of a swiveling flap (R), which is arranged in the exhaust air collection tube (AR) and connected to a rotatable a shaft (DP) disposed within the collector tube wall (AR) and a binary sensor element (B), comprising, for example, an inductive proximity switch and provided with adjusting means (H), eg a screw thread for positioning in the collector tube wall (AR), inside the manifold (AR), a stop (AN) is arranged next to the binary sensor element (B). Suction device according to claim 4, characterized in that the binary sensor element (B) of the minimum binary flow sensor (SE) is embedded in a wall of the housing (K) comprising a pivoting flap (R), which housing (K) it is arranged in the exhaust air collection tube (AR). Suction device according to claim 4 and 5, characterized in that the binary sensor element (B) of the binary minimum flow rate sensor (SE) is arranged on the outside of the storage box (K), comprising a pivoting flap (R) mounted on the rotary shaft (DP). ), one end of which is led out of the housing wall (K) and is rigidly connected to a signaling device arranged on the outer wall of the housing (K). Suction device according to claim 6, characterized in that the signaling device consists of a signal rod (ST) connected at one end to the rotary shaft (DP) of the pivoting flap (R), at whose other end a flag (F) is arranged. Suction device according to claim 6, characterized in that the binary sensor element (B) is displaceably arranged on an adjusting arc (JB) which is fixed on the outside of the storage box (K). Suction device according to one of the preceding claims 1 to 8, characterized in that a filter device (FL) is arranged downstream of the binary minimum flow sensor (SE). A suction device according to claim 9, characterized in that the filter device (FL) is integrated in a program-controlled computer (SPS). The suction device according to any one of the preceding claims 1 to 10, characterized in that a swinging flap (R) is provided as a swinging flap (R) located in the region of the exhaust air outlet (LE).