EP2227678A2

EP2227678A2 - Method for determining filling time

Info

Publication number: EP2227678A2
Application number: EP08864809A
Authority: EP
Inventors: Erhard Fux; Michael Graf
Original assignee: Wittmann Kunststoffgeraete GmbH
Current assignee: Wittmann Kunststoffgeraete GmbH
Priority date: 2007-12-21
Filing date: 2008-12-16
Publication date: 2010-09-15
Also published as: AT506278A2; CN101952692A; WO2009079675A3; US20100312503A1; AT506278B1; WO2009079675A2; AT506278A3; JP2011506227A; TW200927626A

Abstract

The invention relates to a method for determining the filling time for filling at least one material separator (1) provided with a fill level sensor (12) and a requirement sensor (11) in delivery systems made of at least one reservoir (4). In the beginning, with empty lines (3, 6) and an empty material separator (1), the bulk material is delivered out of the reservoir (4) from the time the requirement sensor (11) is triggered until the fill level sensor (12) is triggered, and said delivery time (T REF1) is measured and stored. If the requirement sensor (11) is triggered again, the delivery is carried out again until the fill level sensor (12) is trigged, and said delivery time (T REF2), which corresponds to the delivery time for filling the material separator (1), is measured and stored, wherein bulk material is present in the lines (3, 6) from the first delivery. The delivery time (T REF2) is subtracted from the delivery time (TREF1) in order to determine the emptying time (T LEER), which is equal to the intake time. The lines (3, 6) are emptied within the calculated emptying time (T LEER). If the requirement sensor (11) is activated again, the material separator (1) is triggered with the delivery time (T REF2) and emptied with the emptying time (T LEER), which both represent the filling time when added together.

Description

Method for determining the filling time

The invention relates to a method for determining the filling time for the filling of at least one, provided with a level and a demand sensor, Materialabscheiders in conveyors from at least one reservoir with bulk material, especially in suction conveyor systems preferably with plastic granules for plastic granules processing machines.

Such material separators, also referred to as bulk material separators, are combined either as a single unit or, if several are provided, in a conveyor system and are connected via lines to a storage container. The promotion of the bulk material by means of air flow, preferably via a suction air stream. Mostly all settings are done manually.

Such suction conveyor systems are known per se, as for example from DE 298 15 537 U1, in which the supply of conveying gas or conveying air via a rotatable adjusting sleeve is made.

Another conveyor system is known from EP 0 386 637 A1, which operates detergent dosing devices. In order to enable an automatic, particularly rapid dosing with such a device, a controllable by a control valve valve between the feed and the dosing tank for the compressed air for the pneumatic conveying of the powder is provided.

Furthermore, a device for conveying bulk material is also known from DE 100 39 564 A1. In this suction conveyor the conveying bulk material to be conveyed, a conveying gas is loaded in variable amount. In a conveying line of the already conveyed with the suction conveyor under loading of the conveying gas bulk material is by means of a pressure measuring arrangement of Negative pressure detected and a corresponding control signal is created. In a supply means of the conveying gas in the suction conveyor, a valve is installed, whose opening for the through-flowing carrier gas in dependence on the size of the negative pressure in the delivery line with a control arrangement can be regulated.

A disadvantage of all the above-cited known devices is that although the amount of admixing of air to the bulk material attention is paid, but the filling time is disregarded. This can lead to a poor utilization in too short delivery times and too long delivery times to deposits of bulk material in the lines.

The present invention has for its object to provide a method of the initially cited type, on the one hand avoids the above disadvantages and with the rational operation of such a conveyor system is made possible.

The object is achieved with the method according to the invention.

The inventive method is characterized in that - at the beginning, with empty lines and empty material, the

Bulk material from the reservoir is promoted from the response of the demand sensor to the response of the level sensor and this delivery time (T _R EFI) is measured and stored,

- Promotes the response of the level sensor again when the demand sensor responds again and measures and stores this delivery time (T _R EF2) _> which corresponds to the delivery time for filling the material separator, bulk material being located in the lines from the first delivery,

- the delivery time (T _REF 2) of the delivery time (T _REFI) is subtracted to determine the emptying time (t IDLE), which is equal to the suction time to determine

- the lines are emptied with the calculated emptying time (T EMPTY), - Upon renewed response of the demand sensor, the filling of the

Material separator with the delivery time (T REF2) and an empty suction with the empty suction time (T LEER), both of which add the filling time represent, is performed.

With the invention, it is possible for the first time, especially during a restart of the system or after a bulk material change, the filling time for the filling of material separators in conveyors from a storage container with bulk material, especially in suction conveyors with preferably plastic granules for plastic granulate processing machines automatically to investigate.

With this permanent and performance-oriented conveying and emptying time control according to the invention, the times for filling the system parameters are adjusted fully automatically. As is well known, these parameters are known to drift and are never constant. Due to the fully automatic adjustment according to the invention, these deviations are detected and compensated.

Without the method according to the invention, the values must be adjusted manually, practically without interruption. An advantage of the method according to the invention is that manual adjustments no longer need to be made which require long-serving employees with experience. Furthermore, it is advantageous that no material dwells in the lines due to the empty suction, which can lead to blockages and operational interruptions of the entire system. Such blockages can occur relatively quickly when rewetting the material.

According to a development of the invention, the actual delivery time in the cyclical filling operation is estimated to be shorter, preferably with 2/3 of the delivery time (T REF2). It has been shown in experiments of the prototype plant with the method according to the invention that such a shortened delivery time is sufficient for a rational operation. According to a particular feature of the invention, when the level sensor is _{activated, the delivery} time, preferably the _delivery time 2/3 (T _REF2 ), is shortened by a fixed time unit or, if it is not _{activated, the delivery} time is extended by a defined time unit. This provides the advantage that an automatic stabilization of the delivery time to an operating value for optimum operation is ensured.

According to one embodiment of the invention, a second empty suction is carried out in response to the level sensor during the empty suction. This ensures that no bulk material stays in the pipes for a longer period of time. A bulk-free line is ensured after the filling process.

According to a further feature of the invention, the time (to) from the response of the level sensor to the end of the emptying time (T EMER) is measured and stored during the empty suction. As a result, the emptying time can be adjusted depending on the amount of bulk material supplied to the system-specific conditions, such as pipe lengths or the like.

According to a further special feature of the invention, a calculation of the actual emptying time (T _t EMPTY) is performed, wherein the time (To) is subtracted from the emptying time (T EMER). This actual emptying time is then set automatically during operation of the system and the rational operation can expire.

According to a particular embodiment of the invention, the calculation of the actual emptying time (T _t EMPTY) is performed only after several, in particular five, cyclic filling operations. This ensures that practically the optimum value has already been determined for the funding period. The emptying time adjustment is thus virtually superimposed on the delivery time control.

The invention will be explained in more detail with reference to exemplary embodiments, which are illustrated in the drawing. Show it:

Fig. 1 is a schematic representation of a plant with material separators and Fig. 2 is a flowchart of the method.

1, a suction conveyor for material separator 1 for plastic granulate processing machines 2 is shown schematically. These material collectors receive the plastic granules via lines 3, 6 from the storage containers 4. In order to supply the appropriate plastic granules from the various storage containers 4 to the designated material separator 1, a dome station 5 is provided. In this coupling station leading to the material separator 1 line 6 can be connected to the coming of the reservoir 4 lines 3. The reservoir 4 are connected to a dry air dryer 7.

The reservoir 4 in turn relate the plastic granules from collecting containers 13, wherein the filling of the reservoir can be carried out analogously to the material separators 1.

The suction air necessary for a suction conveyor is sucked in via corresponding fittings 8 with valves which are provided on the material separators 1. This suction air is supplied via a central suction line 9 a two-stage filter system 10 for cleaning.

The material separator 1 has for its filling a demand sensor 11 and a level sensor 12.

Referring to FIG. 2, a flow chart of the method is shown. This method is used to determine the filling time for the filling of a material separator 1 in conveyors from a reservoir 4 with bulk material. The conveyor system is designed in particular a suction conveyor and preferably for plastic granules for plastic granulate processing machines 2. As already indicated in the course of FIG. 1, the material separator 1 is provided with a fill level 12 and a demand sensor 11.

The filling time is determined on the premise that the lines 3, 6 are empty and no other or further material separator 1 from the same line 3 is operated until completion of the filling.

At a start - partial step 20 - or restart - under the above conditions - is at the beginning, with empty lines and empty material separator 1, the bulk material from the reservoir 4 from the response of the demand sensor 11 is promoted to the response of the level sensor 12 and this delivery time (T _REFI ) - substep 21 - measured and stored.

When renewed response of the demand sensor 11 is promoted again until the response of the level sensor 12 and this _{delivery time} (T _REF2 ) - sub-step 22 - which corresponds to the _{delivery time} for the filling of the material _separator 1, measured and stored. Well aware that in the lines 3, 4 of the first promotion bulk material is located.

The _{delivery time} (T _REF2 ) is subtracted - in sub-step 23 - from the delivery time (T _REF -ι) to determine the empty suction time (T LEER), which is equal to the intake time. If, for example, the _{delivery time} (T _REF2 ) is greater than the _{delivery time} (T RE _FI ), then there is an error 24 and an empty suction 25 of the system is carried out. Thereafter, a restart takes place.

In principle, when the demand _{sensor 11 responds again,} the filling of the material _separator 1 - sub-step 30 - with the _{delivery time} (T _REF2 ) and an empty suction with the empty suction time (T LEE _R ), both of which represent the filling time, could be carried out.

On the basis of experience in prototype operation, the actual delivery time in cyclic filling operation - in sub-step 26 - may be shorter, preferably with 2/3 of the delivery time (T _R EF2), estimated. The emptying time (T LE _E R) corresponds to the _{conveying time} (T _REFI ) minus 2/3 of the _{conveying time} (T _REF 2).

In the next partial step 27 it is checked whether the delivery time is smaller than the empty suction time (T EMER). If the empty suction time (T EMPTY) is actually smaller, only one empty suction with the calculated empty suction time (T EMPTY) takes place - partial step 28 - otherwise a second empty suction - partial step 29 - would have to be carried out. So if the level sensor 12 speaks during the empty suction, a second empty suction is performed.

When the demand _{sensor 11 responds again} , the filling of the material _separator 1 - sub-step 30 - is carried out with the shortened _{delivery time} (T _REF2 ) and an empty suction with the extended empty suction time (TL _EER ), which both add up the filling time.

In step 31, it is checked whether the level sensor 12 responds. When the level sensor 12 responds, the delivery time, preferably the delivery time 2/3 (T _R EF2), is shortened by a fixed time unit - partial step 32 - or, if it is not responding, the delivery time is extended by a specified time unit - partial step 33.

In the next sub-step 34, the negative pressure is checked via a pressure switch. When the pressure switch responds, ie at high negative pressure, a blockage is assumed. The system needs to be cleaned and a reboot is required.

In the case of empty suction, the time (T ₀ ) from the response of the level sensor 12 to the end of the empty suction time (T _LE ER) is measured and stored. Furthermore, a calculation of the actual emptying time (T _t L _E ER) is carried out, wherein the time (T ₀ ) is subtracted from the emptying time (T LEE _R ) - sub-step 35.

The calculation of the actual emptying time (T _{t L} EER) is performed only after several, in particular five, cyclical filling operations - substep 36. In sub-step 37, the filling of the material separator 1 is operated with the optimum delivery time and the optimal emptying time.

With this permanent and performance-oriented conveyor and emptying time control, the times for filling the system parameters are set fully automatically. Continuous operation is thereby ensured and any human imperfections are eliminated.

Claims

claims:

1. A method for determining the filling time for the filling of at least one, provided with a level and a demand sensor, Materialabscheiders in conveyors from at least one reservoir with bulk material, especially in suction conveyor systems preferably with plastic granules for plastic granulate processing machines, characterized that

- At the beginning, with empty lines (3, 6) and empty Materialabscheider (1), the bulk material from the reservoir (4) from the response of the demand sensor (11) to the response of the level sensor (12) promoted and this delivery time (T _R EFI ) is measured and stored

(Sub-step 21),

- When renewed response of the demand sensor (11) again promoted to the response of the level sensor (12) and this delivery time (T REF2), which corresponds to the delivery time for the filling of the material separator (1) is measured and stored, wherein in the lines (3,

6) from the first bulk material feed (substep 22),

- The delivery time (T _REF 2) is subtracted from the delivery time (T REFI) to determine the empty suction time (T LE _ER ), which is equal to the intake time (sub-step 23), - the lines (3, 6) with the calculated Emptying time (T _LEE R) are sucked empty (sub-step 28),

- When renewed response of the demand sensor (11), the filling of the material _separator (1) with the _{delivery time} (T _REF2 ) and a vacuum with the emptying time (T EMPTY), both of which add the filling time represent is performed (sub-step 30).

2.Verfahren according to claim 1, characterized in that in the cyclic filling operation actual delivery time is shorter, preferably with 2/3 of the delivery time (T REF2), estimated (sub-step 26).

3. The method according to claim 1 or 2, characterized in that when response of the level sensor (12) the _delivery time, preferably the _delivery time 2/3 (T _REF2 ), shortened by a predetermined time unit or at a non-response, the _delivery time by a fixed time unit (sub-step 32, 33).

4. The method according to any one of claims 1 to 3, characterized in that in response of the level sensor (12) during the empty suction, a second empty suction is performed (sub-step 29).

5. The method according to any one of claims 1 to 4, characterized in that during the empty suction, the time (T ₀ ) from the response of the level sensor (12) to the end of the emptying time (T EMPTY) measured and stored (sub-step 35).

6. The method according to any one of claims 1 to 5, characterized in that a calculation of the actual emptying time (T _t EMPTY) is performed, wherein the time (T ₀ ) from the emptying time (T EMPTY) is subtracted (substep 35).

7. The method according to any one of claims 1 to 6, characterized in that the calculation of the actual emptying time (T _t LEE _R ) is performed only after several, in particular five, cyclic filling operations (substep 36).