|
| | A natural choice for natural stone processing |
|
|
| 
|
|
ITT Flygt's range of submersible, heavy-duty pumps are specially designed for pumping extremely abrasive slurries. Below, we describe two installations in natural stone processing plants, where pumps in the 5500 series are helping to keep production running smoothly, thanks to their high operating reliability and unsurpassed wear resistance.
United kingdom
Marshalls natural stone processing
Although more widely known for its clay brick and precast concrete products, Marshalls in the UK is also very firmly established in the natural stone industry. The company's origins were in the quarrying of natural stone paving and walling back into the 19th century.
Today, the Marshalls Group employs approximately 3,000 people and has sales in the region of 180 million pounds. The company exports its specialist clay brick products to over 40 countries.
Marshalls Natural Stone Processing is located in Southowram, near Halifax, in West Yorkshire. Stone blocks suitable for sawing into paving are quarried locally and transported to the processing factory in weights ranging from about four to 12 tons.
The stone blocks are sawn using powerful saws with diamond-tipped blades. The processing factory, which operates around 100 hours per week, has three eight-blade gang saws, three single-blade cross-cut saws and one two-blade block cutter. These saws receive a constant feed of water for cooling. The stone slurry from the sawing process gravity feeds down channels into a receiving sump approximately 6m x 4m x 2m deep. The inflow into the sump will depend on the number of saws operating at any time, but can reach a maximum of 20 liters/second.
|
Decantation filter press plant eliminates vaccum slurry tankers
Saws in the Marshalls plant receive a constant feed of water for cooling purposes. Stone slurry gravity feeds into channels into a receiving sump.
Until quite recently, the stone slurry was passed through settlement sumps and the resultant settled slurry was pumped out by vacuum slurry tankers.
The slurry, still in a fluid state, had to be discarded, which was not particularly acceptable from an environmental point of view. Marshalls decided to install a decanting/filter press plant to eliminate the slurry tanker process.
The filter press system incorporates a sedimentation cone standing approximately 15 m from ground level. When the system was first installed, the feed to the cone was achieved using a 15.5 kW submersible pump, but the pump lasted only around 12 weeks between major overhauls.
Abrasion-resistans HS 5540
It was decided to try out a pump that was more suitable for operating in the highly abrasive application. An ITT Flygt HS 5540, high-chrome 13.5 kW abrasion-resistant pump was installed, which operates for about five minutes every 15 minutes to deliver around 40 liters/second to the sedimentation cone.
To aid settlement of the slurry, flocculant is dosed into the rising main before the slurry is discharged into the sedimentation cone. Slurry is drawn off from the bottom of the cone into a high-pressure ram pump delivering the slurry into the filter press.
About 15 tons of sandstone slurry filtercake can be produced over a 24-hour period and is now easily discarded.
The 5540 pump was examined after 12 weeks and no visible signs of wear, except for a polished appearance, could be detected on the impeller and wear linings.
In addition to operational gains, the ITT Flygt 5540 has a lower power consumption than the previously installed pump.
Germany
Arca granit und steindesign
The small German town of Brück is located in the new federal state of Brandenburg.
Like many new states in Germany, Brandenburg offers a very favorable investment climate for trading and industry. The region is situated only 30 km from Potsdam, outside the gates of Berlin.
One of the companies attracted to the area was ARCA Granit und Steindesign, which built one of Europe's most modern production plants for granite products in Briick.
Production was started up in March 1993. Marble and granite blocks are cut by six saws with diamond-tipped blades. After cutting, the blocks are processed into tiles, base plates or offcuts for steps, window sills and tabletops.
About 300 square meters of tile are processed during an eight-hour work day. After about 20 hours of operation, more than ten tons of very fine and extremely abrasive solids are produced that have to be continuously collected, flushed with water and pumped away as slurry.
Ten tonsof solids per day
The slurry, consisting of water, quartz sand, diamond grinding dust and marble, is drained into a common receiving sump. From the sump, a submersible ITT Flygt HS 5560 pump delivers the highly abrasive slurry to a settling cyclone, where up to ten tons of solids are collected per day. After settling, the slurry is returned to the flushing and cooling circuit.
The abrasion-resistant HS 5560 is specially designed for high wear applications and is submerged hanging on a chain on the sump floor, requiring no installation work, since the pump is simply lowered into the liquid. The medium is discharged through a hose.
At Arca, the HS 5560 has been in operation ever since the start of production, with virtually no visible signs of wear on the impeller and wear linings.
Reliable slurry seal system
Like all ITT Flygt pumps, the HS 5560 at ARCA and the HS 5540 at Marshalls have two sets of mechanical face seals operating independently of each other in an oil bath.
When pumping slurries, the outer seal is protected from the most severe wear problems. Several design features prevent particles from abrasive liquids from finding their way into the seal:
|
| an isolation zone separates the seal from the wet end, relieving it from pressure created by the impeller. | | | | | any particles entering the isolation zone are expelled by a high-speed rotation plate. | | | | | The mating rings of the seals are of tungsten carbide in a special solid construction for greater abrasion resistance. The rings are also kept working closely together by an encased and protected spring system. | | | | | The isolation zone is flushed with clean water, preventing contaminated liquid from coming into contact with the seals. |
|
A. Before processing, marble and granite blocks are cut by six saws with diamond-tipped blades.
B. Pump sump in which all flushing and cooling water is collected and delivered by a heavy-duty ITT Flygt 5560 pump to the settling cyclone
C. Settling cyclone where solids are separated from the flushing and cooling water.
D. Collecting container where up to ten tons of solids are deposited daily.
|
|
|
|
|
| ![]()
| ![]()
|
|
Home
