Single chamber shot blasting cum painting applications with climate control

With large jobs and critical applications of blasting, painting and/or metallising put together, industries dealing with ship sections, wind mill towers, nuclear/thermal/hydro power plants, tank farms, etc., face numerous bottlenecks in job handling, preventing in-situ corrosion and meeting stringent quality parameters in surface preparation. While it is critical to generate a good anchoring pattern thereby cleaning the surface to SA-2 ? standards such that the paint/protective coating may get properly anchored to the surface, it is equally critical to minimize the timeline between blasting and painting/coating to prevent surface deterioration resulting from oxidation, humidity, and settling of dust particles and other impurities. The conventional applications of separate blast room and paint/coating chambers however, suffer with numerous limitations, some of which are highlighted below.

Repeated Job Handling & Contamination Resulting Thereof

Large and difficult-to-handle jobs often mean a significant increase in timelines between blasting and painting/coating, manpower requirements, capital investments for job handling and yet repeated instances of corrosion in blaster surfaces for reasons stated above occur. Many organizations attempt to use jacks, trolleys and scaffolding to access all areas of the job while also attempting to carry out painting after blasting in in-situ conditions just after blasting, but still struggle against negative factors like evacuation of dust after completion of the blasting cycle, clearing the blast room and its floor of the abrasive media, requirement of multiple air changes, and quality of ventilation air, especially during rainy seasons resulting in high relative humidity.

All these factors lead to formation of mill scale on the blasted surface and therefore poor coating/painting results despite all efforts made.

Quality of Ventilation/Input Air & Difficulty with Curing

The second and one of the most pertinent issues with conducting blasting and painting/coating, especially when the blast room is also used as a make shift paint/coating chamber, is that of input air.

Due to lack of filtration facilities in blast rooms, suspended dust particles and other impurities entering the blast room tend to settle on the blasted surface. This problem is compounded in areas or seasons with high relative humidity, often bringing the production cycle to a standstill.

Also conducting curing at elevated temperatures in the blast room is mostly impractical. Separate blasting and painting facilities or using blast room as a painting facility thus often do not serve the purpose.

Volatile Organic Chemicals, Fume Extraction, Paint Spillage, etc

Some other typical bottlenecks result from painting/coating applications on unusually large surface areas/jobs. Generation of Volatile Organic Chemicals (VOCs) during painting cycle, which is both a safety and health hazard from paints in spite of use of airless painting systems, is a bottleneck for production managers in both meeting pollution control norms, which do not allow free release of these VOCs into the atmosphere as well as securing safety of workers. Similarly fume extraction during the painting cycle, especially when it is conducted on a makeshift basis in blast rooms along with paint spillage etc., agitate the executors of surface coating, so much so that this often compels them to stop their production line for want of cleanliness in this regard, for it is important for them to preserve surface quality as well.

The Solution: Synco Climate-Controlled Single-Chamber Blasting Cum Painting Cell

In order to overcome the aforementioned limitations and provide the perfect solutions for better productivity and unhindered operations, SyncoTM has come up with a specialized climate-controlled single-chamber blast room cum paint cells wherein blasting/painting/ coating are carried out in the same room customized to the user's requirement and with least hassles of job handling while maintaining environmentally friendly conditions. The parameters Synco requires to adjudge a user's requirements are:

• Object surface area before/after blasting
• Preferred abrasive media and desired surface finish
• Desired production rate for both blasting and painting
• Composition and quantum of paint applied per shift
• Desired temperatures during blasting, painting and curing cycles
• Relative humidity levels permissible
• Quantum of VOCs released
• Pollution norms for air, noise and water pollution, and
• Number of air changes required during blasting/painting/curing cycle

While conventional manufacturers and systems are designed to determine and execute basic parameters for blasting/painting, Synco has mastered the additional step of implementing and executing climate control systems for a blast room cum paint cell thereby managing not only blasting or painting parameters but also the requirement of clean and contamination-free high air volumes, large number of air changes, control of humidity levels and maintenance of comfortable temperatures and freshness of air for the operator's safety and comfort. Lastly, VOCs are also controlled to 10% of their lowest explosive levels and are discharged to the atmosphere only within permissible limits.

The achievement does not end here; a conventional technical person would feel that Synco systems achieve the aforementioned parameters by introduction of 100% fresh atmospheric air, its treatment for achieving desired conditions, passing it through the cell and thereafter completely evacuating it. This system however is very expensive in terms of capital cost, power consumption, maintenance, and manpower. Further, 100% VOCs cannot always be passed into the atmosphere. Synco thus has designed a system whereby 90% of the air can be recycled while trapping VOCs and micron-sized suspended dust particles, etc., from the recycled air. For instance, one such system designed by Synco meets the following parameters:

• Relative humidity - 50-55%
• Cell temperature - 26-28?C (50-55?C during curing cycle), and
• VOCs - below 10% of LEL
• All pollution control norms are being met

Benefits of Synco Systems

Reduced power consumption by use of a double-hulled blast room along with a good sealing arrangement and a self-contained fully insulated system. Good air quality and controlled climatic conditions since the input air is filtered and mixed with the recycled air that is all brought to the desired temperature, is washed off all micro particles and VOCs and then introduced to the room wherein two separate streams of air are created for blasting and painting cycles. During the blasting cycle, the air has to pass through the dust collectors; during the painting cycle, it passes through paint trap filters and fume extractors. Arrangement is made for not allowing the floor of the blast room to be contaminated by the unfixed paint material falling on the floor by separate foldable lining arrangement. Different duct sets for air movement with adequate controls are provided for movement of air during different cycles.

The climate of the entire cell is so managed that no outside ingress of atmospheric air takes place. Single room blasting/painting with no job deterioration since the design is such that after blasting, even if the job remains unattended for long durations, it will not deteriorate, being under controlled atmospheric conditions.

Also the system takes away the limitation of doing blasting and painting in patches repeatedly to avoid deterioration in surface quality after blasting, so that continuous blasting gets carried out prior to painting and productivity improves as the number of breaks resulting from change in cycles stands are reduced drastically. Curing is achieved using black sensitive air heaters that have low uptake time, little need for maintenance, easy replaceability and zero spot pollution.

Synco also takes up, if required, responsibility for designing and supply of water softening plants for the make-up water required for the cooling towers attached to the climate control unit and air washing units.

Synco takes consultancy assignments for designing such systems and also takes turn-key responsibilities for execution thereof and thus is probably the only or one of the few sources of providing such holistic solutions of blasting, painting, climate control, control of VOCs and compliance with pollution norms (noise/air pollution) with least power, space and manpower requirements at a substantial saving in capital cost with advanced PLC based controls and man-machine interface facility.

Incidentally, Synco was the only Indian company to technically quality for a major project of this type in India in a global tender, and the design proposed by the company was appreciated and acclaimed by the customer who proposed the same to other global participants in terms of achievement of parameters in terms of cost efficiency and technology, which resulted in most of the initial participants walking out, with a break-through and order for them. They believe the technology can be fruitfully used for achieving better quality and high productivity at lower cost.

Lastly, Synco integrates its system in terms of customized job handling, media recovery and recycling-mechanical, suction-based and vacuum recovery, supplying of all kinds of impact blasting systems-airless centrifugal mechanism and air assisted-pressure, suction, wet and vacuum type blasting processes, acoustic treatment wherever required, supply of air compressors, refrigerated air dryers, air-assisted and airless painting systems, ducting, piping, cabling, lighting etc. It provides construction in MS, SS and Mn Steel material as per needs with zinc/aluminium metallised fabrication if required.

Synco is thus the one-step solution for most blasting and painting requirements.