unglehrt builds high-performance concrete paving stone … · 2020-05-08 · 148 cpi – concrete...

CPI – Concrete Plant International – 2 | 2016 www.cpi-worldwide.com148

CONCRETE PRODUCTS & CAST STONE

Mark Küppers, CPI worldwide, Germany

In the 125th year of its existence, Unglehrtcan also look back on 115 years of experi-ence in the production of concrete prod-ucts. In 1900, i.e. ten years after its estab-lishment as a building company, Unglehrthad already expanded its fields of businessand had begun with the fabrication ofcement pipes and concrete products. In theyears that followed the building companywas expanded by further fields of business- underground construction, road construc-tion and hydraulic engineering - beforeUnglehrt's product range pushed onwardsinto new dimensions with the commence-ment of precast concrete element produc-tion.

That marked the birth of a rapid develop-ment into one of the top suppliers in indus-trial and commercial turnkey construction.Today, project sizes of up to about €15 mil-lion are completed on time at fixed prices.Unglehrt stands for tailor-made conception,high quality of workmanship, adherence todelivery dates and cost-effective solutions.

Unreinforced and prestressed precast con-crete elements are produced today in theplant in Bad Grönenbach. The plant is oneof the most efficient works and is equippedwith modern formwork technology. Thecompany delivers and installs with its ownspecial vehicles and specialist freight for-warders as well as reliable fitting compa-nies.

Success with concrete paving stonesfrom the outset

Unglehrt has been producing concrete hol-low blocks and pavers since the 1950s, ini-tially on mobile block making machines,later on stationary multilayer machines. In1998, shortly before the turn of the millen-nium, Unglehrt put a fully automatic pro-duction line for concrete paving stones intooperation – a board circulation plant withhigh-bay warehouse. Manufacturing is sub-ject to very high quality standards.

Up to this point in time (65 years), the com-pany had its own secure supply of rawmaterials at the Darast site. Due to its highown requirements, however, the limits of the

Unglehrt builds high-performance concrete pavingstone production plant on green-field site

Unglehrt GmbH & Co. KG, 87700 Memmingen, Germany

The building contractor Unglehrt has undergone an impressive development in the 125 years that have passed since its founding inMemmingen in 1890 by the master builder Franz Unglehrt. The company, which was transformed into Unglehrt GmbH & Co. KG in 1979 andis still headquartered in Memmingen, is managed today in the 4th generation by Thomas and Jürgen Unglehrt. Apart from construction work,the name Unglehrt stands for high-quality concrete products. Concrete pavers, including kerbstones, gutters and edging, as well as concretemanhole systems and special articles are produced in the Bad Grönenbach plant, in the midst of the Darast superregional gravel quarryingregion. Unglehrt reacted to the growing demand for monolithic concrete manhole bottoms and a raised quality concept with the modernisa-tion of the manhole bottom and manhole ring manufacture with two new systems from the Italian company Colle (detailed report in CPI4/2014). The next step on the agenda was the modernisation of the concrete block making machine. The original plan was to replace theexisting block making machine, which has been in use at the Bad Grönenbach site since 1998. The outcome was, however, ultimately anentirely different one and a new plant was built on a green-field site in Aitrach, a few minutes by car from Bad Grönenbach. Unglehrt builtthe new production buildings itself. Frima of Emden supplied and installed the concrete block making machine as well as the main compo-nents of the plant equipment on the wet and dry sides. Kniele was commissioned to supply the complete mixing technology, while HSAnlagentechnik supplied the curing rack, complete with façade. The CDS Group from England supplied the associated air recirculation sys-tem. CDS also supplied the noise insulation enclosures for the concrete block making machine and the hydraulic unit.

Unglehrt's new concrete block plant in Aitrach Everything in view: a control panel for the entire mixing equipment islocated centrally in front of the concrete block making machine in theproduction hall

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gravel quarrying gradually came into view. This gave rise to theidea of investing in a long-term solution at a new site with a betterraw materials situation, rather than modernising the concrete blockproduction at the Bad Grönenbach site.

As the largest indirect shareholder of a gravel quarry in Aitrach, theobvious thing to do was to build a new site for the concrete blockproduction here. The relocation has meant a considerable reductionin the concrete consumption at the Bad Grönenbach site and the stillexisting raw materials will last for a much longer time. Unglehrt pur-chased a plot of land in Aitrach for the new concrete block pro-duction plant.

Unglehrt set about looking for suppliers in 2014. Numerous con-crete block plants were visited in Germany and abroad. The overallimpression and the suitability of the package on offer were impor-tant to Unglehrt. By the turn of the year 2014/2015 the suppliershad been finalised. Kniele was awarded the contract for the mixingequipment.

Complete mixing technology from a single source

The building project commenced in May 2015. By August the hallwas far enough advanced for the assembly of the plant componentsto begin. The first tests were already running in November.

Kniele installed conical mixers for the core and facing concretes inthe new plant in Aitrach. The mixers produce a homogeneous mix-ing quality and are also suitable from the production of small quan-tities. Furthermore, the fast, complete discharge and the simple, fastcleaning, which is important above all when changing colour, wereproperties that appealed to Unglehrt.

The automatic mixer cleaning enables colour changes within a veryshort time. According to the supplier it is only important that clean-ing takes place regularly. The washing water is automaticallydrained away and the cleaning water can be reused for the nextmixer rinsing procedure. As a result, very little fresh water is requiredfor the cleaning.

Unglehrt built two concrete silo rows for the storage of the aggre-gates. These are set into the ground and can thus be filled easilyand directly from the truck. This means that the aggregates can bestored virtually frost-free. The aggregates are protected by hydrauli-

All control cabinets are grouped together in one room




cally operated covers. In addition, there isa possibility to load special aggregates forthe facing concrete.

The facings are dosed using vibratingchutes in order to achieve the required dos-ing accuracy. Both in-line silos areequipped with mobile aggregate weighingbatchers.

The aggregates run off the belt directly intothe two lifting buckets that feed the two mix-ers at the higher level. The lifting bucketsare equipped with a rubber lining and aspecial fall protector (double rope drumwith suspension and safety rope).

The cement is stored in the cement silos. Adouble-chamber cement weigher is in -

stalled here to prevent any undesirable con-taminants getting into the facing concretemixer. The controller, including the waterdosing system, comes from Biko tronic.

The concrete mixers empty downwardsdirectly onto discharge belts that transportthe concrete into the silos of the block mak-ing machine. The belts reciprocate so thatthe concrete is distributed better in the feed-ing silo and there is less segregation.

Frima HP1200 block making machinewith core and facing part and boardfeeder

The main component of the new concreteblock manufacturing is the block makingmachine itself, the Frima HP1200 with coreand facing part and board feeder.

As a static board machine, the HP1200was conceived in terms of both its perform-ance range and its functional equipment forvery high production outputs. The mainfocus during the development was on indus-trial suitability and ease of operation. Theresults are a very stable frame constructionas well as components that are easy toinstall and maintain. A further advantage ofthis flexibility concerns the control technolo-gy. Whether central or local automationstructures - extensions can always be adapt-ed accordingly.

The HP1200 can be used for the produc-tion of numerous concrete building materi-als such as pavers, kerbstones, concreteslabs, hollow masonry blocks or gardenelements.

Facing concrete mixer from Kniele; it empties onto a conveyor belt below the mixer

Core concrete mixer from Kniele A board buffer served by a board stack conveyor is arranged in front of the concrete block making machine

Central control station for all system components in front of the CDSnoise insulation enclosure for the Frima block making machine

Windows in the noise insulation enclosure allow a very good view ofthe Frima HP1200 while the production can be followed in real-timeon the monitor.




Unglehrt selected several additionaloptions for the machine equipment, such asthe Frima servo vibration for a further opti-mised compaction of the products.

Frima servo vibrationIn the vibration system, which consists offour vibration-proof synchronous motors,four imbalanced weights are driven perservo converter. A positioning program per-manently synchronises the current positionsof the motors with the positions of the othermotors in the virtual group.

Due to the mass distribution in the drive, thevibrating table is virtually free from vibra-tion at full drive speed. If a vibrationimpulse is required, the mass ratios arechanged by shifting the imbalance posi-tions in relation to one another within aspace of milliseconds.

The vibration system allows very highrepeatability of the force and duration ofthe vibration. The individual setting of thespeed between 2500 rpm and maximum3800 rpm as well as the vibration force of

The concrete mixers empty onto dischargebelts that transport the concrete into the silosof the block making machine.

Frima HP1200 block making machine inoperation

The HP1200 can be used for the production of numerous concrete building materials such aspavers, kerbstones, concrete slabs, hollow masonry blocks or garden elements.


The fresh products are transported by a walking beam conveyor on the wet side to the elevator with 23 levels

Once the elevator is completely filled, the Frima finger car takes over the freshproducts on the 23 production boards.



up to 250 kN make this system very flexi-ble. Through the mass distribution in thevibrating table, as well as the synchronisedcontrol of the mass imbalances, themechanical vibration (amplitude) requiredfor the vibration is aligned linearly and ver-tically.

Individual settings made via the visualisa-tion system ensure an effective forcedosage in the vibrating table, which can beprecisely tuned to the product.

Other additional features include the trans-verse cleaning of the tamper and the cen-tral lubrication. The downtime when chang-ing the product is reduced by the automaticmould change lifting device and mouldintake.

The complete concrete block machine ishoused in a noise insulation enclosuremade of acoustic panels by CDS. Thisreduces the noise level in the productionhall to approx. 85 dB. The Frima HP1200

can be fully observed during productionfrom the control station outside the cabinthrough glass panes in the enclosure. Theprocesses are also all visualised on screens.

A board buffer served by a board stackconveyor is located in front of the concreteblock making machine. This conveyor alsoautomatically supplies the destacker, fromwhich the production boards are fed indi-vidually and cyclically to the concreteblock making machine. Unglehrt produceson softwood boards.

The fresh products are transported by awalking beam conveyor on the wet side tothe elevator with 23 levels. The productsare brushed off with a stone brush if neces-sary.

All Frima components on the wet and drysides are supplied by the central hydraulicsystem.

ProfiNet

The entire Frima system is networked viaProfiNet, allowing a detailed diagnosis ofall local modules up to the displacementmeasuring systems and the individual sen-sors in the system. Networked power sup-plies and circuit breakers provide accurateinformation about the current state, such asthe current load and voltage of individualpotentials and the states of the circuit break-ers.

Specially galvanised curing rack from HS Anlagentechnik for 4186 production boards



Messages for safe functions spanning theentire system such as emergency stop or therelease of safety zones are also handled bythe network function, as is the system-widecommunication, including communication

with external control systems, as well as theremote serviceability of all assemblies suchas frequency controllers, position measur-ing systems and control components.

Energy

Unglehrt has taken a step towards savingenergy costs by installing photovoltaic sys-tems on the hall roof and on a large openspace, with which up to 50 % of therequired energy is produced by regenera-tive means for the company's own con-sumption.

Specially galvanised curing racks fromHS Anlagentechnik for 4186 productionboards

Once the elevator is completely filled, theFrima finger car takes over the fresh prod-ucts on the 23 production boards. The fin-ger car, which features a turntable and sup-port arm adjustment, then takes the freshproducts to the designated location in therack of the drying chamber for curing.

The finger car controller is located next tothe operating console for the concreteblock making machine and is similarlyequipped with a visualisation. One can thussee at a glance the current occupancy ofthe rack and the current activity of the fin-ger car.

Large-chamber air circulation system from CDS

The entire interior air is recirculated bythree main fans arranged laterally




The HS rack system is designed as a free-standing hall with roof and wall claddingand, together with the partition to themachine area, forms a large-chamber sys-tem.

A special feature from HS Anlagentechnikis the special support profile, which not onlymakes the overall design very stable with alength of up to 9 m, but also offers a highlevel of safety during production with inte-grated lateral board guidance right to theend of the chamber.

The spacious rack system consists of spe-cially galvanised steel profiles, HSAnlagentechnik's core product.

ZM300 special galvanisationProtection against corrosion is generallyachieved through the ZM300 special gal-

vanisation. With smaller layer thicknessesthis ternary alloy of zinc, magnesium andaluminium promises at least double the cor-rosion protection offered by conventionallyapplied piece galvanisation (practical testby an accredited testing laboratory accord-ing to ISO 17025, May 2010), while at thesame time exhibiting a much betterdeformability behaviour. The cathodic pro-tective effect of the cut and punch edgeshas also proven to be much better; the inter-metallic connection MgZn2 is available asa sacrificial anode.

Apart from the special galvanisation, theHS rack systems are also characterised bythe fact that they are always free-standing.They therefore form a statically closed sys-tem that doesn't require additional stabilisa-tion.

CDS rounds off the product range forcuring

In the field of air recirculation and curingsystems, HS Anlagentechnik entered into aclose and successful cooperation with therenowned CDS Group from England tenyears ago. As a result, the customer can beoffered the full range of products for curing,with long-proven and continuously im -proved systems. CDS was responsible for the installation ofthe large-chamber air circulation system.With three main fans arranged at the sides,the entire interior air is recycled in order tomaintain a uniform temperature and humid-ity with a condensation-free environment.With a sensor-controlled exhaust fan, theair humidity or temperature can be limitedto an arbitrary maximum value from whichfresh air is added.

The dry side is served from the drying chamber by two lowerators.A special feature from HS Anlagentechnik isthe special support profile with a length ofup to 9 m

The production boards from the two lowerators are merged via a bypass onto a common transport line, a slideway.

Visualisation of the dry side on the monitorat the control station

The stone releaser pushes the stones together, thus releasing them from the production board




This system forms the basis that can be extended if necessary to theCDS EnviroCureSystem. The latter system also allows the activeincrease of humidity and temperature. CDS doesn't work with steamhere, but with diffusers that spray atomised water directly into the airstream. Concrete products can thus be cured all year round underidentical conditions, regardless of the outside temperature.

Two lowerators on the dry side

The dry side is served from the drying chamber by two lowerators.The production boards from the two lowerators are merged via abypass directly behind the drying chamber onto a common trans-port line, a slideway. On the one hand, the use of two loweratorscreates a large buffer on the dry side, while on the other the bypassallows the simple mixing of different batches.

First of all, the boards with the cured products pass through a stonereleaser, which is also designed as a transfer device. This transferdevice can be used at a later date to serve a parallel finishing sys-tem, which is to be installed in the next step. Currently, the stonereleaser pushes the stones together, thus releasing them from theproduction board.

The production boards with the released concrete blocks movecyclically via the slideway to the cuber. If the product allows, twolayers are doubled up first. To do this the cuber picks up a completelayer from the production board and sets this stone layer down ontop of the stone layer on the next production board that drives in.

If the product allows, the cuber first doubles up two layers. The cuberthen picks up the double layer and places it on a wooden pallet ona further conveyor.




The cuber then picks up the double layerand places it on a wooden pallet on a fur-ther conveyor. As soon as the desired pack-et height has been reached, the packetmoves via a roller conveyor to the coversheet feeder and the strapping machinefrom Cyklop.

Once a packet leaves the packet assemblystation on the wooden pallet, a new wood-en pallet is provided from the wooden pal-let magazine.

The production boards are automaticallybrushed off directly behind the cuber andthen turned by the board turner to ensureeven loading of both sides. The productionboards are then automatically collectedand stacked by the board stacker.

The complete production board stack ispicked up by the board stack conveyor andeither placed in the board buffer in front ofthe block making machine and thus feddirectly back into the circulation, or tem-porarily stored in the spacious board bufferrack with three levels - also built by HSAnlagentechnik - until the next use.

Like the controller for the wet side, the con-troller for the complete dry side is alsoequipped with the Frima 3D visualisation.

Ambitious project with strong partners

"In terms of the schedule, everything wentaccording to plan in all aspects", saidManaging Director Jürgen Unglehrt, who isvery satisfied with the implementation of theproject. Unglehrt was able to complete theproduction buildings on time and the sup-pliers all met the deadlines. Trial operationwas thus able to begin as planned at theend of 2015.

"Despite the variety of the technology, pro-duction started up smoothly", said MrUnglehrt, describing the commissioning ofthe new production line and praising thegood partnership with the suppliers.

The concrete block production is to run inboth plants in future. Unglehrt's intentionwith the new plant is to increase capacities.The stated goal is four shifts of concreteblock production per day. �

UNGLEHRT GmbH & Co. KG Allgäuer Str. 31 87700 Memmingen, Germany T +49 8331 1070 F +49 8331 [email protected]

CDS GroupCinderhill Industrial EstateWeston Coyney RoadLongton, Stoke-on-TrentStaffordshire ST3 5JU, EnglandT +44 1782 336666F +44 1782 599279 [email protected] www.cds-group.co.uk

FRIMA GmbH & Co. KGStedinger Straße 1226723 Emden, Germany T+4949215840F+494921584128 [email protected]

HS Anlagentechnik C.V.Veldkuilstraat 536462 BB Kerkrade, The NetherlandsT +31 45 5671190F +31 45 5671192 [email protected]

KNIELE Baumaschinen GmbHGemeindebeunden 6D-88422 Bad Buchau, Germany T + 49 7582 93030F + 49 7582 [email protected]

FURTHER INFORMATION

Stand B1.144

Stand C1.238

Stand B1.144

Stand C1.404

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The finished stone packets move via a rollerconveyor to the cover sheet feeder and thestrapping machine from Cyklop.

The fully packaged stone packets stand onthe buffer conveyor awaiting removal by thefork-lift truck

The boards are automatically brushed,turned by the board turner and automatical-ly collected and stacked by the board stacking device.


unglehrt builds high-performance concrete paving stone … · 2020-05-08 · 148 cpi – concrete...

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