ATEX Drum Wash System
ATEX Drum Wash System Description
The ATEX Drum Wash System was designed to wash both Drums and Pallets that had become
contaminated with a flammable and explosive chemical. The ATEX Drum Wash System
was required to operate in a hazardous environment designated as ATEX Zone 21 T135
ºC explosive environment. All equipment and materials used were therefore suitable
and certified for use in this ATEX Area.
ATEX Drum Wash System Washing Booth
The wash water used within the ATEX Drum Wash System was heated to 80ºC to ensure
the removal of the chemicals involved and it was therefore essential that the washing
operation be entirely contained. It was also a pre-requisite to minimise the quantity
of water used for two reasons, firstly it is expensive to heat the water to 80ºC
and secondly the water contaminated with the explosive material had to be filtered
to permit the waste water to be disposed of. The Washing Booth was manufactured
from stainless steel box section base frame with the main section manufactured from
3mm stainless steel sheet. After a drum or pallet was loaded into the Wash Booth,
the safety interlocked enclosure door was closed and latched. Once this door was
latched closed, this enabled the wash process to be started in a completely contained
environment
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ATEX Drum Wash System with Safety Interlocked Enclosure
Door open to show spray nozzles
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ATEX Drum Wash System Filtration & Pumping System
The pump used to feed the spray nozzles contained within the wash booth was capable
of delivering 500 Litres of water per minute at 80ºC. The total cycle time to thoroughly
clean the most contaminated item could be as long as 10 minutes which would give
a total water usage per wash cycle of 5000 Litres. The number of items to be cleaned
per week was approximately 50 giving a weekly heated water usage of 25000 Litres
which would be prohibitively expensive and unviable. As a result of this, the water
was passed through an extremely effective filtration system which reduced the total
weekly water usage to 500 Litres. The 500 Litres of water used by the ATEX Drum
Wash System was stored in a stainless steel storage tank mounted beneath the filtration
system platform. The four stage filtration system was easily accessible via the
platform for regular maintenance and replacement of filter cartridges as required.
On initiation of a wash cycle the water is pumped from the storage tank by a Pneumatically
Operated Double Diaphragm Pump and sprayed at high pressure through Rotary Jet Heads
and fixed spray nozzles onto the item being washed.
The used wash water drained very quickly into a wash chamber sump and from there
was pumped via a second Diaphragm Pump through the filtration and heating system.
The first filter was a cyclonic separator unit, which extracted the bulk of the
solids from the contaminated water. The wash water then passed through progressively
finer bag filters which removed the remaining contaminants. To ensure maximum filtration
efficiency and to maintain the water temperature the wash water was circulated through
the heat exchanger and filters during the loading and unloading of the wash chamber.
ATEX Drum Wash System Heat Exchanger
To maintain the wash water at its optimum wash temperature, the water was passed
through a Spriax Sarco Heat Exchanger. The Heat Exchanger used heat from the customers
2 bar steam supply, which provided sufficient heat input for the water as well as
providing heating for the hot air drying unit. The Heat Exchanger could not meet
the requirements of ATEX Zone 21 T4 and is therefore in a separate room.
ATEX Drum Wash System Chamber Extraction & Hot Air Drying System
The effect of spraying the drums and pallets with high pressure hot water to clean
them was the creation of a considerable amount of mist, which was extracted from
the wash chamber. Once the extraction was complete, the same system was used to
blow hot air, created by the heat exchanger, over the washed drum or pallet so that
it was dry when removed from the wash chamber. The Hot Air Drying Unit was mounted
remotely from the main wash system.
ATEX Drum Wash System Electrical Control System
The whole Electrical Control System for the ATEX Drum Wash System is PLC controlled,
permitting the operator to select different wash cycles for the various items to
be processed. The washing machine can be programmed to carry out a self washing
process and can dump the filtered water to drain as required. In this instance the
wash water was changed once a week, even though no trace of the chemicals being
removed from the drums and pallets could be found in the wash water. The quality
of the used water was such that it was despatched directly into the normal sewage
system for disposal without further treatment. These options were selected and controlled
via a very simple ATEX approved push button station. The main control panel was
mounted remotely.
ATEX Drum Wash System Specification
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DESCRIPTION
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ATEX DRUM WASH SYSTEM |
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DRUM DESCRIPTION
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1100mm HIGH x 630mm DIAMETER |
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ROTARY JET HEADS
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TOFTEJORG TJ20
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WASH PUMPS
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BLAGDON DOUBLE DIAPHRAGM AIR OPERATED
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BASE ARRANGEMENT
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BOLTED TO THE FLOOR
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ELECTRICAL SUPPLY
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415V, 3 PHASE, 50Hz |
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COMPRESSED AIR SUPPLY
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5.5 BAR MINIMUM
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STEAM REQUIREMENT
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2 BAR MAXIMUM
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WATER SUPPLY
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NON-POTABLE (FIRE WATER) @ 6 BAR MAXIMUM |
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CONTROL CIRCUIT
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24Vac (STANDARD)
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ELECTRICAL RATING
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IP65
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