Product category:
Hazardous area interfaces, Enclosures
News Release from: Cooper Crouse-Hinds | Subject: Explosion-proof controls
Edited by the Processingtalk Editorial
Team on 26 May 2008
Explosion-proof controls for loading dry
materials
A range of hazardous area equipment for use on loading systems for handling dry, potentially-explosive bulk materials, including cement, alumina, sugar, petroleum coke, grain and sulphur
Cooper Crouse-Hinds (CEAG) manufacture terminal boxes, control stations, emergency stop controls and enclosures that enable dust-free loading of dry bulk materials Based in Stockton-on-Tees, Cleveland Cascades designs and manufactures a range of custom-designed, retractable loading chutes for the handling of dry bulk materials Using its patented Cascade system, the company has more than 400 systems in operation around the world in various ship, silo, rail and road tanker loading applications
This article was originally published on Processingtalk on 23 Sep 2008 at 8.00am (UK)
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The company is considered to be a market leader in its field and its product the industry standard.
Ray Ollis, Electrical Design Engineer at Cleveland Cascades comments: "We've been purchasing CEAG equipment for many years now, via Scattergood and Johnsons, our local distributor in Leeds.
When it comes to offering loading chutes for hazardous environments, we provide a detailed design specification to Scattergoods, who would then source the required control stations and terminal boxes from CEAG.
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Up to now, the CEAG equipment has been very reliable and we've never had a single problem from the customer once we've installed the system".
All other dry bulk loading systems currently available on the market enable bulk material to freefall and in doing so, pull volumes of air down with the falling material.
This air needs to escape at the base of the chute and when doing so, carries the separated material particles, causing highly visible dust emissions, which is not only a nuisance to the local environment but which also creates a potentially explosive atmosphere.
These systems would require dust extraction to attempt to recover this dust-laden air.
As Ollis explains: "Unlike free fall chutes, the Cleveland Cascade chute gently supports the material being loaded all the way down the vertical length of the chute and in doing so, maintains a constant and low velocity, which together with the cone shape, keeps the material in mass flow form.
The low velocity means the material does not pull air down with it and so if there is no air to escape, there is no dust generated".
The Cleveland Cascade system constrains the material to flow in a zigzag path through inclined cones to limit the flow velocity and therefore prevent particulate separation, material degradation and segregation.
In this way, dust generation is virtually eliminated at source, without the need for expensive and energy-intensive dust extraction and filtration systems.
The Cleveland Cascade system is so successful that Cleveland Cascade is the only company in the world who can currently guarantee dust emission levels down to less than 5mg/m3.
Ollis continues: "We normally have to retrofit our loading chute to the ship or tanker.
This involves a lot of engineering effort, both mechanical and electrical.
For example, if the customer needs to load 200 tonnes an hour of cement to a tanker, we have to design our chute and associated control equipment to cater for this.
This means we sometimes have to use customised control stations and junction boxes".
According to Ollis, chute controls can be integrated with the existing PLC equipment or operated independently with a dedicated controller.
The controls for the chute would normally be located in a gallery, close to the conveyor, or remotely.
In either situation, especially when ATEX certification is required, CEAG control stations are used, which typically comprise emergency stop-start controls, reset and raise controls, stainless steel or plastic enclosures (depending on the application) and terminal boxes.
In order to monitor the loading of dry bulk materials, a pair of level probes are located at the bottom of the loading chute, terminated to a CEAG junction box.
If the job requires full installation, Cleveland Cascade would then provide full chute controls.
"People are starting to wake up to the ATEX regulations and more jobs are now including this type of hazardous area equipment.
Out of the nine enquiries currently on my desk, three require ATEX approved control equipment.
We're currently tendering for a contract in Spain with the oil company Repsol, which involves a lot of ATEX Zone 21 control equipment.
It's for a loading system for filling open road wagons and we will use CEAG controls and terminal boxes for this application," says Ollis. Request a free brochure from Cooper Crouse-Hinds ...
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