Innovative alternative to picking in the central area of cities--ecological technology.

Braun, Alfons ; Dumitrescu, Constantin Dan ; Lammer, Brigitte 等

1. INTRODUCTION

Although the cable owners like Telecom, electricity and gas suppliers, municipal sewage and heating suppliers, energy supplying companies, refineries, oil, gas, petrol and chemicals distributing companies recommend the manual uncovering of underground installations, damage is still caused to them, which can produce massive pollution on wide areas.

Remedy costs affect not only those who have caused damage, but customer services. Thus, in 1998 in Karlsruhe Langensteinbach the telephone system fell because of a disruption by a cable excavator. No manual drilling can meet the quality requirements because labour productivity is very low, the quality of work is inappropriate and particularly the price/ quality ratio is totally inappropriate.

Taking into consideration that the market share is relatively low reported to costs incurred in the design and manufacture of specialized equipment on these functions, equipment manufacturers also have sought of a compromise solution: to use common components for certain structures (motor, the structure of resistance system running, etc.) that adapt to new functions and then to implement specific functions required by the new product (Pride, 1997). This ensures a manufacturing costs reduction, while ensuring the minimum necessary indicators to ensure that the product quality is achieved. Taking into account the globalization of the European countries economies, the manufacturing process can develop by using a project management at the European level, with an impact and conclusive on the direction of reducing the manufacturing costs. (Grigorescu, 2008)

The development of a strategy of this type requires prior calculation of a global economic efficiency indicator to motivate the new management model and a design, a collaborative project management, which includes all employees, with a clear indication of "chain activities", of the products that are taken into consideration- time of delivery, of the delivery costs, of the technical characteristics of components that are the project's objects, of the suitable logistics system and the quality conditions imposed to components (Yvan, 1998).

Although from some literature approaches (Taroata, 2000) the industrial production is necessary as a "total system"; the approach of horizontal cooperation strategy at a European/ international level highlights that each production system needs to be considered as an individual. A process of continuous restructuring is taking place at the macroeconomic level, the structures of production, economic efforts being directed towards an efficient and stable market economy; This is possible only by creating new structures of production, new mechanisms operating in the economy and even more, changing the human mentality and components at all levels of the society (Negrila, 2003).

2. THE SUCTION TECHNIQUE

The element that provides the basic technical characteristics of the excavator with suction aspiration equipment is the high suction volume. It is taken from the supplier, as is constructive, for use on a lorry chassis, the training system is done from the gear box of a truck through an especially built power plug and a system with training wheels toothed belt in order to retrieve the vibration transmitted by the training engine.

Excavators by suction are over dimensioned dust vacuums mounted on truck chassis. They may suction sand, water, mud or rocks up to a maximum diameter of 25 cm and a weight of 20 kg. The suction of the material is done by vacuuming using a hose. It is operated using a hydraulic system. The Inside diameter of the hose is of 25 cm. With the help of extension tubes it can dig holes to a depth of 10 m from surface.

The transportation environment of the vacuumed material is the very strong air current which is produced by a system of fans involved in the secondary outlet power propulsion engine of the car. Couplings help to a smooth and continuous increase of fans speed in order to achieve the desired parameters. A hydraulic system consisting of two circuits provide consumers with energy. Control of the office equipment is assured from a panel or a remote control. This allows servicing the equipment directly from the suction area. Aspirated material is deposited into a container. With a noise emission of 82 dB the vacuum excavator is below the limit of 85 dB allowed in the central part of the city. An integrated compressor allows the vacuum excavator to work independently with different tools. By tilting, the side of the container is completely empty. If damage is done to water pipes or gas, contaminated soil can be vacuumed without auxiliary aggregates to be used. Due to current strong air, equipment can work at uncovering the damaged gas pipes without any danger of an explosion. In the container and filtration compartment here is a high performance filtration system composed of three steps. The filtration unit with the latest generation, made of self-cleaning and renewable filters, ensures an air free of dust discharged in accordance with the TA Air regulations. Noise dampers allow the operation of the gear in residential neighbourhoods. By the intake hose the material and the air get sucked into the container. By reducing the flow velocity and assuring a system of cyclone air, heavy particles are separated due to the centrifugal force and due to the gravity (1st step). The air that is still containing impurities is led through a channel connecting to the 2nd step filtration. At this point another quantity of particles is dispensed in the air flow. This is achieved by increasing the empty bag's volume leading to a reduction in the rate of air flow.

The 3rd filtration step presumes that the air flows through the channel to the five batteries filters so that it arrives absolutely clean to the fans, complying with the TA Air regulations. The materials used in the manufacturing filters are allowed by the Entertainment German Federal Institute for Labour Safety. With the automatic cleaning filters system the air pulses by counter clockwise direction (Jet Pulse). The filters are cleaned at regular intervals during work. The possibility of initiating separately a cleaning cycle exists.

An advantage of the filtration system used until now is that the filtering patrons are uniformly cleaned due to the horizontal flow of air motion. The full empty of sediment is very important in order to preserve the filtering ability of fine filters. In this way the vacuum is always ready to work. After it passes though the coolers, the air is discharged into the environment through the noise mitigation system. It uses a backstage and resonance absorption in a well-established proportion. Noise dampers are optimized using specific computer programs, which take into account not only the quantity of air, but absorption parameters such as loss of hydraulic power and air speed.

3. ADVANTAGES OF VACUUMING WITH A MAJOR IMPACT ON THE ENVIRONMENT

Doubling the aspiration capacity is useful for users who heavily need to dig in the metropolitan area or far beyond. The technology corresponds to the principles of nature, without affecting the environmental quality: Time saving of approx. 500% compared to the manual unfolding; Decline by more than 50% of the area for the unfolded intervention; Less excavated material and thereby reducing transportation costs and a minimum volume of removed material; Complete solutions with a single equipment (air compressor, water tank, equipment for excavation and transport of removed material), thereby diminishing the collateral effects, such as blocking the street because of large areas of the site and requires a single parking place for the excavator; Immediate intervention without the need for site plans of underground facilities; Removing the excavated organic material; The area of work remains clean; Earth can replace the roots of trees without affecting them.

4. FIELDS OF USE

MTS Company of Germersheim, a manufacturer of excavators geared with coolers offers a safer alternative method of unfolding by suction.

Suction excavators equipped with several fans at MTS permit to solve the problems of daring aspiration. I.e. the use of suction excavator finds its applicability in damage to pipelines or gas and water transport systems. Unexpected damage caused to water pipes can be removed using the suction excavator in a very short time. The aspiration of the wet or contaminated land can be done without problems. This is particularly important damage to gas pipelines. The excavated material is sucked into the container truck and can be transported immediately after the drill ends. With specially equipped vacuum excavators, tubes with diameters up to 5m can be unclogged in short time periods. The tubes are up to 2.5 m clogged with contaminated material. Removing the material is done up to depths of 8 m and 80 m lengths. At the same time waste water flowing through the channel is permanently aspirate and separated within the equipment. To maintain the excavator sucking as much in service, once the container is filled with material excavate, it may be tiled in a separate pail transport.

The new machine filtration system ensures suction devoid of danger, even for contaminated materials.

An integrated lifting system on the equipment allows raising and lowering the inspection or aspiration vehicle, and the hoses in the extension of sewerage.

Bringing the material to the suction mouth was resolved through various systems. In addition to the vehicles of inspiration and ejection on caterpillar tracks ordered by distance, mills or small excavators with suction devices are used. The energy of these devices is ensured by the sucking excavator.

5. EXCAVATIONS IN THE METROPOLITAN AREA

Vacuum drillers are effective in places where there is or is alleged that cables, pipes or other are buried.

If an excavation is needed in a "critical" area then the following rules apply: Information about the location of underground facilities has two aspects. The executants must be documented regarding the site and other restrictions and must take care not to damage these or themselves On the other hand the responsibility lies with the underground facility owners.

In practice, however information about the location of cables is insufficient or simply does not exist. Then there remains nothing to do than to measure or draw them. Information is obtained by consulting the DIN 1998 norm.

6. CONCLUSIONS

Given the annual increase in the length of utility lines within the perimeter of cities, the need to replace them, to change defective valves, has increased. The vacuum excavator can be used in all these works, particularly in the perimeter of cities where land has already been out once.

The use of suction excavators creates both an interesting alternative to the executor and the owner of the underground installations.

The excavations may be done without danger of damage to exist, at much lower costs (i.e. with a time saving of 500%) compared to manual digging.

Suction excavators are built in a variety of sizes. Depending on the size of the collection container they can be mounted on truck chassis with two, three or four axes.

Despite the duplication of suction power and efficient energy the suction system patented by MTS and the development training managed to maintain the same size of the intake. This concept is characterized by a high durability in service and reduced maintenance costs.

The product is a part of the European project that has the following objectives:

* The jointure and interaction of the best technical and technological solutions that are produced by European specialized companies.

* The final product's assembly involving minimal costs, conditioned by a project imposed reliability.

* The assurance of available market segments in Europe, Asia and USA for this family of products.

7. REFERENCES

Grigorescu, A. (2008). Practica managementului proiectelor (Project Management Practice), Uranus Publishing, ISBN: 978-973-7765-68-0, Bucharest

Pride, W. (1997). Business- ; Houghton Mifflin Company Publishing, ISBN: 973-590-049-1, Boston

Negrila, A. (2003). Restructurarea intreprinderilor aflate in dificultate (Restructuring of companies in dificulties), MIRTON Publishing, ISBN:973-661-000, Timisoara

Taroata, A. (2000). Managementul si ingineria sistemelor de productie (Management and Manufacturing Systems' Engineering), SOLNESS Publishing, ISBN 973-99226-8, Timisoara

Yvan, A. (1998). Management strategic, Economica Publishing, ISBN 973-590-040-8, Bucharest