WO1996017740A2

WO1996017740A2 - Floor conveying system with individual drive vehicles and electrolyte capacitor-type storage battery

Info

Publication number: WO1996017740A2
Application number: PCT/DE1995/001735
Authority: WO
Inventors: Martin Rosenau
Original assignee: Rosenau, Viktor
Priority date: 1994-12-07
Filing date: 1995-12-06
Publication date: 1996-06-13
Also published as: DE19545544A1; DE9419568U1; WO1996017740A3

Abstract

In conveyor systems comprising individual vehicles equipped with electric drive motors and in which the current is supplied via sliding contact lines laid in the floor, for safety reasons, only a very low voltage can be applied to the sliding contact lines. This frequently leads to breakdowns owing to the fact that the film of corrosion and dirt which builds up on the sliding contact lines is not destroyed to a sufficient extent owing to the intensity of the electric field being too weak in this film, which then acts as an insulating layer between the current collector and sliding contact line. These breakdowns only occur in places but have a serious effect on the operation of the system (the vehicles stop at the wrong time or move in jerks). In order to overcome this problem, the vehicles are provided with energy storage batteries whose storage components consist of electrolyte capacitors or gold caps with an energy supply sufficient for the vehicles to pass over the critical locations.

Description

Description of the patent application

Title:

Floor conveyor system with single drive vehicles with

Electrolytic capacitor storage

Field of application: conveyor technology

Note: The term "hallway" is to be understood in the present case in terms of conveyor technology: it means that it is a conveyor system with vehicles (and not a roller conveyor), in which the wheels attached to the vehicle (1) and carrying the vehicle ( 8) Roll on a surface (4 or 10) under the vehicle (1 and not over the vehicle (as with overhead conveyors, overhead overhead conveyors, etc.).

This surface can be the floor (4) directly or a substructure above the floor, an intermediate floor in the building or a protective grid web (Fig. 2) etc., even if these are built hanging from the ceiling and / or provided with an additional substructure (9) are. description

Different systems of industrial conveyors in which loads are transported by individual vehicles are known, and the advantages and disadvantages of each system are also well known due to the many years of experience.

For example, in the case of floor conveyor systems in which the vehicles are moved by mechanical towing means (e.g. ropes or chains), the effort associated with the towing means is generally very high. In addition, with systems of this type, the requirements regarding operation in workshops

Noise levels are not always maintained.

Laying the towing equipment for floor vehicles over their route (on the ceiling) is rarely practiced because the conveyor system has to be sacrificed too much space in the building.

When laying the entraining agent in the ground, the setting up of pits for the relatively voluminous drive and economy stations, deflection devices and switches, and the establishment of the channel for the entraining agent along the conveying route are associated with problems such as alterations to the building and its foundations .

Consequence: High investment costs, long construction times, high maintenance costs and very little flexibility when modernizing (if the route layout has to be changed).

Systems with vehicles with electric single drive are free from most of the disadvantages mentioned above, but the big problem here is the energy supply of the drives.

In the known driverless transport systems (AGVs), this problem is solved in that the vehicles are equipped with rechargeable batteries. The vehicles are guided to their central stations by an electronic guidance or navigation system. The known disadvantages of these systems are:

High susceptibility to faults; In the event of an accident, the use of highly qualified personnel is often necessary; the large quantities of acids (or alkali solutions) contained in the batteries are a source of danger in the event of accidents; Disposing of the heavy, bulky batteries, which often have to be replaced due to their limited lifespan, is a costly and environmentally damaging affair.

The disadvantages include the high purchase costs (per vehicle). In order to keep these within tolerable limits, reltivally cheap batteries are mostly used, the weight of which is very high per energy unit and which emit significantly less energy than they consume when charging (especially if they are no longer brand new).

The consequences are further evils: a very low overall efficiency of the system, frequent recharging of the batteries and their short lifespan.

Attempts to equip industrial vehicles with relatively simple individual electric drives and to supply the electrical current required for the drive via conductor rails have so far not led to any significant breakthrough.

The installation of the conductor rail above the route (e.g. under the ceiling of the building) is rarely practiced with industrial trucks in buildings, mainly because of the problems that arise with the mechanical guidance (steering) of the vehicles and also from

Space constraints.

For safety reasons, only a very low voltage may be used when laying the conductor rails in the floor (protective voltage, in Germany e.g. 60V for DC voltage - see reference 1: DIN VDE 0100, part 410). At this voltage, the contact problems known in electrical engineering occur at low voltages: Even a small amount of corrosion film or dirt on the contact line's grinding surface leads to disruptive interruptions in the power supply (vehicles run jerkily or stop completely).

Contact interruptions at low voltage are mainly caused by the fact that the electrical "breakdown", which is important for maintaining contact, of the continuously forming corrosion film (or also a layer of dirt) from the contact point is often absent because the field strength of the electrical field is too low.

In addition: Low voltage means high current, which leads to increased electrical erosion (through sparking) and thus to the progressive destruction of the conductor line and the contact problem on the conductor problem being constantly aggravated in the event of contact interruptions.

The known solution to the contact problem on the conductor rails is that you do not use conductor rails with a low voltage in harsh industrial or operating conditions, the following applies to conductor rails in such conditions: from 380V upwards, with electric locomotives - up to 30,000V.

If people are at risk of being touched, contact-protected conductor lines are used.

But even at high voltages there may be interruptions in the power supply from the conductor rail, but for other reasons than the above, e.g. B. Iron leap in electric locomotives or passing a junction of the conductor rail.

The solutions to the problem known in technology (at high.

Voltages) can be divided into 2 groups: - First group: The drive motors are not supplied with electricity for moving the vehicle, the section without energy supply from the conductor rail is overcome by the kinetic energy (momentum) of the vehicle. Only the most important small energy consumers (especially the on-board electronics and the braking system) are supplied with energy. For this purpose, either the drive motors are used in the function of generators, or energy is taken from any rechargeable energy storage device whose energy supply is sufficient for the small consumer (e.g. smaller batteries) for the duration of the interruption of the power supply from the conductor line but no power is supplied to the drive motors for moving the vehicle.

Example for this group: - Site 5 (see directory of sites):

P. 15, 1st column, 3rd paragraph;

Here the drive motors are used in the function of generators (to maintain the normal functions of the on-board electronics and above all the braking ability of the system).

Very often z. E. In the case of electric locomotives, the combination of drive motors as generators with a "buffer" battery is used.

Attempts to apply this method, which is suitable for railroad locomotive operation, to conveyor vehicles and locations where the power supply is interrupted have been unsuccessful with industrial vehicles to date, firstly because of a too small supply of kinetic energy of the moving vehicle, because mostly the vehicles move at a speed significantly below

60 m / min (under 3.6 km / h), and secondly because you are not dealing with individual interruptions, but with the mentioned contact problem at low voltages, which is a different behavior of the drive than with individual interruptions Rim. Second group: The drive motors are supplied with electricity for the locomotion of the vehicle by an energy store, which can supply sufficient energy for this purpose.

Examples of this group:

A). with rechargeable battery as buffer storage:

- Reference 2: U.S. Patent No. 4,129,203, item 78;

- Location 3: PCT / US92 / 07443, item 42;

- Reference 4: Patent DE2912558C2, claim 6,

and Fig. 1, item 26. The use of "giro" energy storage devices for the purpose of bridging energy supply gaps is known in particular in electric road vehicles with overhead lines (for example in some trolleybuses) stored in the form of kinetic energy of a flywheel rotating at high speed.

C). with power condensers (or capacitors for energy electronics) as buffer storage:

- Reference 6: U.S. Patent No. 4,145,618, description,

Column 1, from line 36; Claim 1; Fig. 1, 2 and 3. Through the low pass LC (see Fig. 1 to 3 of the site) at the input of the electronic converter (static inverter) short voltage interruptions, z. B. by sparking on the bracket (pantograph), balanced (smoothed).

In the event of a long interruption in the power supply from the conductor rail, e.g. B. when passing a catenary separation point or with a larger iron jump, the drive system from the supply of irr. Capacitor -C1 stored energy. Since the inertia of the drive system cannot be influenced by this capacitor when starting, its capacity is only limited by the space available in the vehicle, its weight and from the point of view of its acquisition costs.

A noteworthy disadvantage of the system is the energy loss in the resistor R and in the varistor Z when charging the capacitor Cl (see FIG. 3 of the site).

Capacitor memories are rarely used as a bridging power source to power the vehicle because of a number of problems that are encountered.

One of them is that because of the steep drop in voltage at

Discharging the capacitor only a relatively small part of the stored energy can be used because the voltage for the normal function of the vehicle drive a certain

Must not fall below the minimum value. By using an additional voltage converter system, the part of the stored energy that is being used could be increased.

However, this solution is too expensive (and too voluminous).

The use of the capacitor as an energy store often fails due to the large volume per stored energy unit (especially in systems with a relatively low operating voltage).

The higher the working voltage of a capacitor, the larger its volume. However, since the amount of energy stored in the capacitor increases proportionally to the square of the voltage, capacitors can be used for voltages that are typical for electric locomotives (12,000 V or even 25,000 V), in which sufficient amounts of energy can be stored with a relatively small volume. A capacitor with a volume of 3 or 5 cubic meters can usually be easily accommodated inside an electric motor. At low voltages and less spacious vehicles, a memory made of power capacitors can be large

Space requirements are often not accommodated.

Electrolytic capacitors, which can store a multiple of energy at the same volume (compared to power capacitors), can solve the volume problem in vehicles with energy supply via conductor rails such as locomotives, trams, and the like. not be used because the high power requirement of these vehicles means that high voltages (up to 30,000 V) are used to keep the current size and thus the heat losses in the conductor rail and the arcing on the pantograph within reasonable limits.

The highest working voltage for which electrolytic capacitors can still be manufactured is 500V (because of the special properties of their dielectric and because of the electrochemical processes that only take place in this type of capacitor - see reference 8). Gold caps are only known for voltages up to a maximum of 75V.

So there are very different areas of tension.

The situation is different for conveyor vehicles if they are to be supplied with electrical energy via conductor rails installed in the floor or directly above the floor.

The classic solution of using higher voltages and using contact-protected conductor lines cannot be accessed here, because without special protective measures, such as demarcation by fences along the entire length of the route, contact-protected conductor lines with a voltage higher than the protective voltage may not be laid in this area .

To an appreciable amount of energy for bridging purposes for the drive in the voltage range below the protective voltage in a capacitor bank, which are designed from power capacitors for heavy current technology, to be able to store here, the memory would have to be several times larger than the vehicle - see reference 9 (power and energy requirements of driverless transport systems). It is about battery-powered vehicles, but with

same energy requirement as for industrial trucks with power supply via conductor rail.

The solution to the problem, especially for industrial trucks with energy supply via conductor rails for voltages in the protective voltage range:

Electrolytic capacitor storage or gold caps storage (5, Fig. 1), whose energy supply in the event of interruptions in the power supply from the conductor line (3) not only to supply the vehicle electronics (and other small consumers), but mainly as an energy source for the drive motor 2 (or drive motors) is used.

The energy supply in the storage tank is replenished when the power supply from the conductor rail is intact.

Modern electronics and electrical engineering offer the option of designing the energy store by expanding the circuit so that it can also be used as a spark-suppressing device (in the event of contact interruptions on the conductor line). This can cause electrical erosion at the

Conductor line to a low (long life of the

Conductor) ensuring dimension are suppressed.

Modern electrical engineering also offers the possibility of designing the drive unit in such a way that the drive speed remains constant given the sizes of the voltage fluctuations that occur in practice due to the discharge and charging of the storage capacitor. The conductor rail channel (7), which can also serve as a guide channel for the vehicle, can be designed to be very compact, so that only a small groove has to be milled out to lay this channel in the floor. In addition, the conductor rail duct can be laid on the parts of the route where it is permissible for reasons of space, on the floor (without sinking) or also above the floor. When introducing the system, there are no high construction costs, there are only short construction times for the

Conveyor system required. And in the case of modernizations, the route layout can be changed with little effort (compared to systems with mechanical towing equipment).

The system contains no highly sensitive sensitive components and no dangerous chemicals, it is robust and easy to maintain and can also be controlled very easily in larger, branched systems (compared to the complicated, sensitive and fault-prone control of the battery-powered vehicles, which is caused by electromagnetic field or laser beam pulses the route).

A major advantage of the system is, among other things, that the vehicles can move easily on different levels (E1 and E2, Fig. 6) in workshops. This makes it possible to use a process that is often used in power-and-free conveyors and monorails:

The vehicle is loaded on the floor level, then it is z. B. raised by a hoist (12) and moves as an overhead transporter z. B. on the protective grid level. Around the pantograph (6) does not necessarily have to be removed from the guide channel (3). It remains in a sliding line and guide channel piece (14) attached to the lifting carriage (13) of the lifting mechanism.

The vehicle can be brought down to the floor level for unloading.

In this way, space can be kept free in workshops, where it is valuable - on the floor level, and used where there is usually a lot of space wasted - at overhead level.

Claims

Claims =================

1. Industrial conveyor system, in which the individual vehicles (1) are equipped with drive motors (2) and are steered by mechanical guidance and in which the power supply is effected via conductor rails (3), the voltage applied to the conductor rail being the value prescribed for safety reasons the so-called protective voltage does not exceed and where "hallway" in terms of conveyor technology is to be understood as a floor (4) or substructure (9) on which the conveyor vehicles roll, characterized in that for the purpose of overcoming the difficulties known in electrical engineering with the electrical contact at low voltages; Difficulties, which are mainly caused by the fact that the electrical "breakdown" required to maintain contact with the continuously formed corrosine film and possibly also a layer of dirt due to too low a field strength of the electric field in the corrosion film (or layer of dirt) often fails with every vehicle an electrolytic or gold capsule capacitor store, in which a supply of electrical energy is stored in one or more capacitors, mainly for the purpose of supplying the drive motor (or the drive motors) with current for moving the vehicle, but also for supplying other energy consumers on the vehicle if the power supply via the conductor rails is interrupted due to contact faults on the pantograph.

The energy supply of this storage is filled up when the energy supply from the conductor rail is intact.

2. Conveyor system according to claim 1 or 2,

characterized in that a chemical electrical energy source (e.g. battery) is used for energy storage together with the capacitor.

3. conveyor system according to the above claims,

characterized in that, in addition to its storage function, the energy store is also used to suppress spark formation in the event of contact interruptions on the conductor line (for example by expanding the circuit).

4. conveyor system according to the above claims,

characterized in that the version of the conductor rails (conductor rail channel 7) is used for mechanically guiding the vehicles (with or without servo assistance on the vehicle).

5. conveyor system according to the above claims,

characterized in that the wheels (8) of the vehicles do not run directly on the floor, but on profiles (10) which serve as running surfaces for the wheels or as guide profiles.

6. conveyor system according to the above claims,

characterized in that the conductor rail channel (7) is sunk in the floor, its upper edge being flush (Fig. 1) or not flush with the surface of the floor.

7. conveyor system according to the above claims,

characterized in that the conductor rail duct (7) is laid on the entire route or only on parts of the route directly on the floor (without sinking) or above the floor.

8. Conveyor system according to claim 7,

characterized in that the conductor rail duct (7) laid on the floor is provided with ramps (11, Fig. 5) on the side, mainly to make it easier for all kinds of vehicles (e.g. forklift trucks) to drive over it.

9. conveyor system according to the above claims,

characterized in that a conductor line (3, Fig. 3) in the interior of the conductor line channel (7) is covered and arranged with the opening in a horizontal direction, so that the associated sliding contacts (6) can be pivoted sideways into the opening (Fig. 3 ).

10. Conveyor system according to the above claims, characterized in that two conductor lines (3, Fig. 4) in the interior of the conductor rail channel (7) are covered and arranged with their openings in a horizontal direction, so that the associated

Sliding contacts (6) can be pivoted laterally into the openings (Fig. 4).

11. Conveyor system according to the above claims, characterized in that the vehicles move on different levels (E1, E2, Fig. 6), for. B. on the floor and on a protective web (Fig. 6 and Fig. 2).

The change from one level to the other can e.g. B. by lifting or lowering by a lifting and lowering mechanism (12).