DK151565B - PLANT FOR PNEUMATIC TRANSPORT OF OBJECTS - Google Patents

Description

in 151565

The invention relates to a system for the pneumatic transport of crash goods as set out in the preamble of claim 1.

Such a plant is known from GB publication specification 2,038,750. The guide material is continuously introduced into the conveyor line at its front end, then divided into plugs by means of compressed air which is intermittently introduced into the conveyor line and then pressed in this plug form through the conveyor line, where necessary. energy is provided by the expansion of the transport gas between each two plugs, causing these 10 "compressed air pads" to be replenished at periodic intervals. This refilling is accomplished by means of the high-pressure transport medium sidewall over the valves, which are temporarily and sequentially opened for a fixed period of time by means of the electronic control unit. As a result, most of the transport medium 15 is supplied over the lateral line. In this mode of operation, no pressure detectors are in principle required in the main line, since the system is operated with purely empirically invented and values to the electronic control unit for the delay of opening a valve in relation to the opening time of the valve in the flow direction. Similarly, the duration of the opening and the repetition time (frequency) of the opening of each valve can only be invented experimentally. Apart from the disadvantage that this plant can only be used in a very particular, namely the short-sketched method of transport mentioned above, the experimental invention of the three parameters mentioned is hardly feasible in practice, 25 missing any feedback on a starting blockage, and there thus, while searching for the most advantageous values for each parameter, repeated blockages in the conduit must occur. Removing these blockages is a difficult task. Of course, the possibility of placing a pressure detector in the conveyor line is also mentioned. However, this gives a signal at a pressure drop in the transport line and thus is not suitable to warn in time for a starting blockage which causes a pressure rise. Presumably the pressure detector serves only to achieve a synchronization between the successive opening of the valves and the rate of flow of the individual plugs, and thus to deliver the starting pulse for the pulse sequence, namely when the air pad between each two plugs in the conduit is expanded so much that it can no longer supply any shear energy and therefore must be replenished.

In addition, from the journal "Verfahrenstechnik", 1978, booklet 4, page 151565 2 200, illustration 12, there is known a plant comprising a conveyor line with a parallel conveying medium side line from which additional transport medium flows into a conveyor section if the pressure drop in the relevant transport line section exceeds an adjustable value. To this end, membranes must be arranged on the conveyor tube at intervals, each acting over a piston on a common lever system, and each piston preceding the flow direction is simultaneously designed as a valve which, if exceeded by a spring, is predetermined 10 the desired value of the differential pressure opens a plug line connecting the lateral line to several air supply lines on the transport line. Except that this bulky mechanism precludes economically acceptable realization of such a plant, such a plant would have the disadvantage that the spring with which to adjust the differential pressure would have to have a considerable bias so that small pressure variations would not trigger unwanted valve vibration. Furthermore, in order for this biasing force to be overcome by the mechanically sensed differential pressure, the membranes must, in accordance with the ratio "force = pressure x area", be dimensioned with a particularly large area. This means that the pressure-sensing and pressure-transmitting elements must be large and thus become correspondingly expensive. For transport lines with a diameter up to approx. 80 mm they are too large because the pipes then have too strong curvature for the planar membranes.

Furthermore, the large membranes are too sensitive to pressure shocks and 25 to the wear caused by the solid flow. Furthermore, the large membranes impose large penetrations between the conveyor line and pressure sensor, which results in solid deposits on the membrane, which eventually deteriorate their pressure sensor function.

DE-patent specification 1,781,025 discloses a pneumatic conveying system with a conveying medium sideways extending parallel to the conveying line, from which additional conveying medium is introduced into the conveying line via controllable valves. In front of the controllable valves, measuring points are placed on the transport line. The controllable valves are adjusted by means of the signals emitted from these measuring points. The technical task of this known conveyor system is to move the bulk cargo through the transport conduit into individual plugs which are spaced apart by means of transport medium pads. In order to prevent the interconnection of the individual plugs, additional transport medium is introduced along the transport line into the pads of transport medium between the plugs. To this end, the milestones, whose mileage principle depends on light rays or radioactive rays, record whether there is a plug or cushion of transport medium at the site of the additional transport medium.

Further, from German Patent Specification No. 2,022,962, a conveyor system is known with a conveying medium siding running parallel to the conveyor line, from which additional conveying medium is introduced into the conveyor line along the conveying line via valves. The technical task of this conveyor system is to equalize the pressure drop across the conveyor section. However, since the supply valves at this known conveyor system are not controllable, it cannot be predicted at all how much additional transport medium flows into the individual conveyor sections along the conveyor line. Also, as long as the supply of extra transport medium cannot be controlled, it cannot be predetermined how the pressure flow in the transport line changes during the supply.

Also from German Patent Specification No. 2,219,199, a conveyor system with a conveying medium sideways extending parallel to the conveyor line is known, from which additional conveying medium flows into the conveyor line via pressure controlled valves. The valves placed in the transport medium side line force a defined pressure drop in the transport medium side line along the conveying section. The technical task of this conveyor system is to transport bulk goods in plug form with automatic regulation of the air supply in the event of transport disturbances. A serious disadvantage of this known conveyor system is that additional transport medium towards the end of the transport line is first blown from the transport medium side line into the transport line when the transport line is pumped up from its front end to that location (see column 4, lines 54-62).

30 However, this entails an unnecessarily high air consumption and thus an uneconomical operation and a slow dissolution of plugs in the transport line.

Also, from German Patent Specification No. 2,305,030, a pneumatic conveying system with a conveying medium sideways extending parallel to the conveying line is known, from which additional conveying medium flows into the conveying line over valves.

At this conveyor system, the side conduit seen in the flow direction is closed at the point where the pressure in the transport medium side conduit for the first time exceeds the pressure in the conduit, and at the applicable location, inflow of additional transport medium from the conduit into the conveyor conduit is possible. A disadvantage of this conveyor system is that during transport only additional transport medium can flow into the conveyor line at a single location of the entire pipeline at a time, which is not sufficient for an interruption-free and energy-saving operation of the conveyor system.

From German publication specification No. 2,403,533, a further pneumatic conveying system is known with a conveying medium sideways extending parallel to the conveying line, from which 10 additional valves flow into the conveying line over valves. The inflow of the auxiliary transport medium is controlled in such a way that, through the first valve seen in the flow direction, a compressed air shock is discharged into the transport conduit thereafter through the next and the subsequent, etc. with increasing faster discharged compressed air shock corresponding to the increased flow velocity along the transport route. When the compressed air pulse has reached the end of the transport medium side line, a pressure sensor ensures that the cycle is repeated. This transport system also has the disadvantage that, at a certain point in time, only at a single point on the transport section is affected by the transport process by means of additional transport medium.

German publication specification No. 2,412,142 discloses a conveyor system having a conveying medium siding running parallel to the conveyor line, from which 25 additional conveying mediums are injected into the conveyor line. At this transport facility, the load to be transported is introduced into portions in the transport line. In this way, the individual batches of bulk cargo must allegedly move momentarily forward, the material being alternately moved and stopped. In accordance with this state of oscillation in the conveyor line 30, additional air mediums must be flowed over the air injectors in phase or phase shift into the conveyor line over the entire conveying route. The injectors are controlled either via transport medium intermediate containers along the transport route or over a time control. Apart from the fact that the print in question does not contain any 35 references at all to the difference in effect between a phase opening and a phase-shifted opening of the air injectors, and what is to be understood by the concept of phase, this control of the air injectors has the serious disadvantage, that at different locations of the conveyor line no sensing of the instantaneous vibration state is sensed, nor is there any feedback to the control on the effect of the additional supply of transport medium.

However, this is an absolute prerequisite for the oscillation of the transport tube, which, due to friction, is attenuated towards the end of the transport section, is continuously restored and maintained. Thus, at this known transport system, one must expect that the desired oscillation is further attenuated and eliminated entirely by air supply at the wrong time or at the wrong places, respectively.

Finally, from DE-patent 2,550,164 a pneumatic conveying system is known, in which an additional conveying medium flows into the conveying line, passing parallel to the conveying line, passing through valves. This conveyor system is very similar in its design and task position to the conveyor system known from German Patent Specification No. 2,305,030 and differs from this only in that between each two valves serving to close the lateral line, several inflow points from the lateral line are arranged. to the transport line. This plant also has the disadvantage that at a defined time, only extra transport medium can flow into the transport line in a single section of it.

20 Before and after this section, sections of the transport line cannot be affected by the system at this time.

The object of the invention is to improve a plant of the kind mentioned in the first place in such a way that it can be used for both continuous and non-continuous transport methods and can be easily adapted to different load cargo and allows transport with the greatest possible safety against disturbances and under low energy demand and wear and tear on the plant.

This task is solved according to the invention by the properties of the characterizing part of claim 1.

30 In summary, it can be said of this solution that, in contrast to all known plants, the principle proposed here is the use of the principle of feedback to the control of the change in the transport process caused by an additional supply of transport medium, thereby providing an adapted regulation of the transport process. the transportation process simultaneously over the entire transport route.

Certain powdered materials can be transported slowly and without clogging danger by imparting a vibration to the gas / solid flow which ensures that the interconnection forces of the particles are overcome for the most part, thus eliminating clumping of the product and depositing it in the transport line. However, the vibration applied at the front end of the conveying section is attenuated due to internal friction as well as friction to the pipeline over the conveying section. This disadvantage is eliminated according to the invention in that the control unit is arranged to open the individual valves in dependence on the pressure fluctuations of each of two successive pressure sensors in such a way that the vibrations which are assigned to the goods at the beginning of the transport line are maintained throughout its length. Thus, by means of the system according to the invention, it is possible to maintain the oscillation at the appropriate rate at the appropriate rate at the appropriate locations of the conveyor line.

In other types of impact goods, a pneumatic transport with vibration of the gas / solid flow is not possible or disadvantageous.

Also, for such species of cargo, a uniform transport with a low transport speed and as high loading of the transport medium with transport goods as possible is sought. The closer the transport speed and loading of the transport medium with the cargo approach the clogging limit, the more economical and product-friendly the transport is.

A threatening clogging of the conveyor line is manifested by a local increase in the load concentration and thus by an increased pressure drop in this area of the conveyor line. The danger of clogging the conveyor line according to the invention is eliminated in that the control unit is arranged so that it will check the pressure difference between the pressure sensed by each two consecutive pressure sensors, compare the pressure difference with a predetermined maximum value for this pressure difference and open the associated valve. if the maximum value is exceeded. This allows for a high charge of the transport medium with transport goods and low transport speed, while eliminating the danger of clogging, with the electronic control unit, in which the maximum permissible pressure drop for each transport line section is programmed, by a signal from the pressure detectors that it the maximum permissible pressure drop is exceeded in a transport line section, immediately the controllable valve belonging to the transport line section opens, which is kept open until the pressure drop is again reduced to below the maximum permissible value by means of the additional transport medium flowing in that transport section. Furthermore, the electronic control unit can easily be converted to the most advantageous values, and at the same time they are e.g. in connection with the known constructional and mechanical conditional disadvantages described from the journal "Verfahrenstechnik" eliminated. Furthermore, according to a further design using a recording apparatus or an optimization program, the optimal value of the differential pressure can be found for each transport line section during the transport process.

To obtain the most energy-efficient transport relative to the load flow rate, the control unit may be connected to at least one electrical measuring device disposed at the beginning of the transport medium side conduit for measuring the flow amount of transport medium through the transport medium side conduit and delivering the measured value in the form of an electric signal. .

An embodiment of the conveyor system is schematically shown in the drawing.

Guide material is passed over a pressure vessel 2 which, via a supply line 3, is fed to a transport medium, into a transport line 1. The guide material is pneumatically transported to a separator 4. A transport medium side line 5, connected via a connection 6 to a transport medium source, runs parallel to the conveyor line 1. The conduit lines 7 in which the electrically controlled valves V1, V2, V3, V4 are located are provided from the transport medium side line 5.

Following the controllable valves, the plug lines over check valves lead to transport medium supply points 9, in each of which a filter is not shown. As shown in the drawing, several transport medium blow-in locations may be assembled in a group provided with an additional transport medium over a common controllable valve. Between the groups of blow-in points and in front of the first and after the last transport medium blow-in place, electric pressure detectors S1, S2, S3, S4, S5 are arranged. From these pressure sensors, signal lines 10 lead to an electronic control unit 11, where the in-signal signals are evaluated as input signals. From this control unit, signal lines 12 lead to the electrically controlled valves V1-V4, which are set by the output signals of the control unit. For certain transport tasks, it may be convenient to place a gas flow meter 13 at the front end of the transport medium side line. This meter also transmits the measured value electrically over a signal line 14 to the control unit 11. As additional input signals, the electronic control unit 11 can be supplied with freely selectable parameters or initial parameters.

A transport cycle begins with the filling of the pressure vessel with the load. Thereafter, the pressure vessel at the closed outlet valve (not shown in the drawing) is inflated with pressure gas over the supply line 3. Then the actual transport process is opened by opening the outlet valve with continued supply of transport medium over the supply line 3 to the pressure vessel and to the front end of the transport line.

In the case of vibration transport, the transport medium over the supply line 3 is introduced shock-wise into the pressure vessel 2 and at the front end of the transport line. The resulting pressure oscillations cause the transported goods to oscillate movements, thereby eliminating the mutual adhesive forces between the particles, and thus, despite the large load of the transport medium with the impact load, no 15 plugs form in the transport line. Due to internal friction along the conveying line, the desired vibration in the conveyor pipe would disappear very quickly if it were not constantly restored by the delivery of periodic compressed air pulses into the conveyor pipe. In the short-term opening of the controllable valves V1-V4 20, vibration transport is applied over the supply points 9 at periodic intervals compressed air pulses in the transport line. In this way, the desired vibration in the transport line is maintained all the way to its end. In order for the vibration to be constantly restored and not lifted, it is necessary that the compressed air pulses enter the conveyor tube at the correct time at the various supply points. To this end, the electric pressure sensors S1-S5 give a signal to the operator or the electronic control unit about the pressure changes in the transport pipe. By systematically controlling the opening duration and switching on of the controllable valves V1-V4, the 30 optimal mode of operation is found. This is achieved when the pressure fluctuations in transport -c due to the compressed air pulses are amplified instead of decreasing. Once the optimum mode of operation of the controllable valves V1-V4 has been found, this setting of the conveyor system is maintained as long as the same kind of load is transported.

35 In many products, vibration transport is not possible or not advantageous. Nevertheless, in order to protect the product to be transported and to reduce the wear and tear on the plant, special attention can be given to as slow transport as possible. There is a constant danger of plug formation in the transport line. An imminent blockage at a location in the transport line causes an increased pressure drop in the transport medium at that location. The electric pressure sensors S1-S5 signal to the electronic control unit about the pressure at the relevant points in the transport line. If the maximum permissible pressure drop which is programmed in the electrical control unit for each transport line section is exceeded in one section of the transport line between two pressure sensors, the controllable valve belonging to that transport line section is opened until the pressure drop via the additional transport medium entered in this transport line section again is reduced to below the maximum permissible value.

The transport medium quantity measuring apparatus 13 gives a signal about the consumption of extra transport medium through the transport medium side line, so that one can conclude the energy consumption for certain transport modes.

The operation of the electrically controlled valves is done by logically linking the input signals to the electrical or electronic control according to optimization criteria that have been programmed or determined by the operator according to the task positions described above. For checking the operation of the conveyor system after manual changes to the setting of the electronic control unit, the input signals, i.e. the pressures in the conveyor line and, optionally, the transport medium consumption in the transport medium sideline, upon request or continuously on suitable recording apparatus, such as an oscillograph, line printer, Braille or print shop. In this way, not only an adjustment of the optimal transport condition of the transport system but also the continuous monitoring of the transport system during operation is possible.

When switching to the transport of other load goods, both the control algorithms and the freely selectable input parameters can be quickly replaced by program change. Thus, according to the various optimization criteria (eg, an energetically advantageous or slowest possible transport), the different types of bulk cargo can be transported without disturbance with one and the same transport system. The ideal setting of the conveyor system can be conveniently made from a control panel because all information about the current state of the system is constantly or on demand displayed on the control panel. In this connection, it is also appropriate to place feedback or acknowledgment lines (not shown in the drawing) from valves V1-V4 to control unit 11, which reports the actual operating path I of each valve so that this actual operating position f .g. signal lamps can also be displayed on the control panel. This makes it possible to detect and locate incorrectly functioning valves, as well as any other disruptions in operation, particularly quickly.

As valves, in the case of regulation, valves with only two positions, i.e. “Open11 and“ closed ”completely adequate. However, to further minimize the clean air requirement, if a correspondingly more complicated control unit is accepted, valves can be used which can either be brought into a defined intermediate or throttle position or be opened or closed, respectively, by means of suitable electrical control signals.

The check valves and filters in the supply system for supply of extra transport medium prevent the transport of goods from entering this system and thus ensure the absolute functional safety of the system.

Claims (5)

151565 Patent Claims. An installation for pneumatic conveying of bulk cargo with a transport medium side conduit (5) extending parallel to the conveyor line (5) arranged over valves 5 (V1-V4), which are controlled by means of an electronic control unit (11), is connected to the conveyor line (1) and at least one pressure detector (S1-S5) located in the conveyor line (1) connected to the electronic control unit, characterized in that several pressure detectors (S1-S5) are arranged at intervals in the conveyor line 10 (1) and that the control unit (11) is arranged to combine the pressure signals (S1-S5) output signals logically with parameters set as desired values, such as pressure, pressure differences, time intervals and frequencies which characterize the transport state and in deviations between the actual transport state and the desired transport mode electrically sets the controllable valves (V1-V4). System according to claim 1 for vibration transport, characterized in that the control unit is arranged to open the individual valves (V1-V4) in dependence on the pressure fluctuations sensed by each two successive pressure sensors (S1-S5) in such a manner. 20 that the vibrations imparted to the goods at the beginning of the conveyor line are maintained throughout its length. System according to claim 1 for continuous transport, characterized in that the control unit is arranged so that it will check the pressure difference between the two pressure sensors (S1-S5) followed by each pressure, compare the pressure difference with a predetermined maximum value for this pressure difference and open the associated valve (V1-V4) if the maximum value is exceeded. System according to any one of claims 1-3, characterized in that the control unit (11) is connected to at least one measuring device (5) arranged at the beginning of transport medium side lines (13) for measuring the flow rate of transport medium through the transport medium side line and transmitting the measured value in the form of an electrical signal to the control unit (11). System according to any one of claims 1-4, characterized in that for each electrically controlled valve (V1-V4), there are several transport medium injection sites (9) on the transport line (1).