Cell Covers/Hoods

Acid Aerosol Control

Designed by EXPERIENCED PROFESSIONALS for Real World OPERATORS !

Desom has been involved in the design and implementation of cover systems for the Electrowinning industry since the mid 1970’s. Desom has designed and installed numerous types of covers depending on the particular process application:

  1. Fixed ventilated cell covers
  2. Flexible unventilated cell covers
  3. Flexible ventilated cell covers
  4. Porous membrane cell covers
  5. Anode covers
Desom’s VentiCover©
Desom has used its experience and extensive physical and computational modeling expertise to develop the proprietary VentiCover© System. VentiCover© overcomes the following problems that have been historically associated with ventilated covers on production Electrowinning Cells:

  • Build up and plugging within the cover
  • Build up and plugging of the exhaust ducting
  • Handling of covers during harvesting
VentiCover© Design Features

The Desom VentiCover© is unique to the industry:

  • Low Profile
  • Flat Top — Anti-skid Surface
  • Single Piece Construction — No “Wings”
  • Optimized Fluid Flow Design
  • Self Cleaning

Superior Design

Extreme environments present challenges for all types of systems, often creating the need for additional temperature regulation practices.

Desom’s Close Capture Ventilation System was developed as an alternative option to our Cross Flow Ventilation System for plants in cold weather climates.

Requiring reduced air volumes, higher capital costs are easily offset by lower air heating and cleaning costs.

  • Designed to minimize exhaust volumes required to control in-plant conditions.
  • Provides maximum control of acid contamination above the cells.
The VentiCover© System allows:
  • Unlimited man access to the top of the cells
  • Full visibility of the critical hanger bar, contact areas of the cells
  • Complete access to the cells for cell cleaning
  • Self-cleaning without dilution of the cell electrolyte
  • No restrictions on production rate
  • No requirement to add additional crane height
  • Simple design not requiring elaborate control and monitoring systems
  • Full automation of cathode harvesting
  • No manual labour involved in retrieving or positioning covers
  • Solid Fiberglass Reinforced Plastic (FRP) Construction for long service life

Liberator Cells

In the Electrorefining of Copper, it is necessary to deplete the copper from the spent electrolyte. This is typically done in a two stage ElectroWinning process called the “Liberator Section”.

As Arsine gas can be generated in the Liberator Section, it is necessary to cover the cells and exhaust the aerosols and gases through a scrubber which is typically monitored for the presence of Arsine Gas.

Desom has developed a number of hood designs for use in Liberator Cells.

  • Fixed, Ventilated Hoods (shown here) which are moved by the overhead crane and stacked on adjacent covers during cathode harvesting.
  • Fixed Anode Hoods (not shown) fixed to the anode and exhausted through scrubbers.

Steel Pickling Line

For extreme environments where reduced ventilation volumes are needed to control the acid emissions from process operations, the Desom VentiCover© System provides the most efficient control of secondary contaminant emissions from the process. In hot HCl Steel Pickling Lines, the FRP VentiCover© System provides 100% capture of the acid mist and moisture emissions from the horizontally fed pickling operation.

In this sheet steel pickling operation, the pickling tanks are provided with a Desom VentiCover© System. Slip joints on the exhaust duct system and an overhead crane allow quick and easy access to the process for inspection and maintenance.

Chloralkali Cells

In the Chloralkali Process, Chlorine gas is generated from the electrolysis of Sodium Chloride. Desom’s VentiCovers© provide the non-corrosive, tight fitting seal that is required over each cell which allows the collection of the Chlorine gas from the electrolysis process.

The Chloralkali VentiCover© System includes covers, sealing clamps, ducting, scrubbers and fans for a totally integrated chlorine recovery system.

Push Pull VentiCover© System
In some process applications, access is required for the process operations. In such an instance, it is not always possible to enclose the offending process. Desom’s Push Pull VentiCover© System is the answer.

This installation demonstrates a Push Pull VentiCover© System on a batch operation steel pickling line. Steel coils are lowered by crane into each successful pickling bath. Before the installation of the Desom Push Pull VentiCover© System the whole area was contaminated with HCl mist with resulting high corrosion of the material handling systems, service equipment and building steel.

High Speed Continuous Pickling Line

In high production continuous steel pickling lines, Desom’s FRP VentiCovers© have found a natural home. Rugged, corrosion resistant FRP construction provides for low maintenance and long service life.

In the installation shown here each 2.5m X 6m VentiCover© is hinged on the backside of the production line. With the VentiCover© in the raised position, quick and easy access is provided to the production line for inspection and maintenance personnel. An exhaust system mounted on the underside of the VentiCover© support provides the exhaust volume necessary to control the HCl mist emitted from the high speed production process.

Molten Metal Launders

In the Copper Smelting Process, copper and slag are tapped from continuous Smelting and Converting furnaces. Desom developed a High Temperature (HT) VentiCover© System to control the heat and fume losses from the tapping process. With the installation of the HT VentiCover© System, heat and fume losses were eliminated; launder maintenance was reduced; worker heat stress was eliminated.

With the HT VentiCover© system in place, productivity increased, accidents were reduced and worker turn-over decreased! These Before and After photographs tell it all!

All Desom VentiCover© Systems start out as a need to improve the in-plant working environment surrounding a particular process. From this need definition, Desom develops a project goal and through the use of Physical and Computational modeling a VentiCover© System is designed which is uniquely optimized to meet the required project goals.

For the EW Tankhouse environment, the need for an improved Acid Aerosol Control system became clear when the emission rates of high production EW Cells exceeded the cost/benefit ratio of ventilation systems to control the in-plant environment. This was particularly true for Magnesium Dioxide EW process operations which due to the high electrolyte temperatures and gassing rates associated with this particular EW process prevented the use of dilution ventilation.

The evolution of VentiCovers© for use in high production Copper EW Cells only required that operators accept the restrictions imposed with the use of covers. With this acceptance, Desom has adapted its proven VentiCover© System to provide the most cost effective, least restrictive and lowest maintenance cell cover system for the efficient capture of acid aerosols from EW Cells.