As more and more stringent environmental policies adopted by various agencies a need for an Environment friendly blasting is a must. In order to have a good manual blasting operation a neat and clean blast room is required. CLEANBLAST with its years of experience in design and installation of various Blast Rooms in India and Middle East is a trusted partner for your return on investment.
Typical enclosure of a blast room will be made out of m. s. folded and bolted panels or PU form sandwich panels duly supported with formed structural members. Booth will have option of semi-automatic or full automatic recovery system ﬁtted. The internal walls of a blasting booth are protected by abrasion resistant rubber sheets. Proper illumination using blast proof LED lighting are necessary for a higher produc- tivity. ‘Man Door will be provided on the sidewall of the booth. Air inlet louvers and exhaust hoods are provided on the front and rear wall of the booth respectively for ventilation and dust extraction. The jobs can be handled in and out of the blast room manually, by fork lift or in trolleys. Generally, Steel Grit and Garnet are widely used as preferable abrasive in a blast booth.
After placing the job in the blast room the operator should enter the blasting Booth, through the ‘Man Door’, fully protected with operator’s gear. The dust collector, grit recovery system and the lights put ‘ON’. The operator should connect the air supply to air regulating valve ﬁtted at operator’s waist belt. Open this valve for breathing air supply to the helmet.The operator should operate the remote control provided on blast hose directing the blast nozzle on the job. The abrasive gushing out of blast nozzle would clean the job. The operator should observe and clean the complete job. Put another job for blasting and repeat the process.During blasting operation, the abrasive falls on the ﬂoor and should be collected sieved, air washed and segregated and then feed to the blast hopper/storage cum feed hopper for re-circulation.
Recycling system is provided to reclaim the useful abrasive from the spent abrasive . The spent abrasive is mixture of broken abrasive , dust , useful abrasive and other contaminants . The proportion of useful abrasive reclaimed depends on the initial size and type of abrasive used . In case of steel abrasive the brake - down rate is nominal, whereas expandable abrasive has very high rate of brake-down.
Totally enclosed sheet steel fabricated motor control center is provid- ed with desk type design for front operation and access to interior from front hinged door. The panel is coated with anti-corrosive paint after pre-treatment and stowing enamel. The panel is complete with all internal wiring and connections and generally comprises:-
1. TPN fuse switch unit
2. Supply "ON" indicating lamps
3. Voltmeter with selector switch and back-up fuses
4. Ammeters for all motors above 15 HP
5. A set of 3 ½ bus bars
6. DOL starters for all motors with necessary back-up fuses.
7. Star delta starters for all motors from 10 HP onwards
8. Sequential locking system for abrasive conveying drives
9. Defeat sequence system for maintenance purpose
10. Various interlocking and safety system
11. Emergency stop push button.
In order to ensure fairly uniform cross draft across the blast room particularly at the level of operation, extraction hood is essential. By providing small resistance across the perforated plate, the extraction is spread over larger area thus ensuring fairly uniform cross draft. The extraction hood is also expected to trap useful abrasive escaping to the dust collector. The extraction hoods are strategically located inside the blast room opposite fresh air supply louvers so that most of the air extracting the dust will blow across the operating area.
The function of the Fresh Air Supply Louvers is to allow outside air to enter the room for extracting the dust and getting exhausted after ﬁltration. The fresh air supply louvers are expected to trap any abrasive trying to escape during blasting and admit only outside air. The Exhaust hood and fresh air supply louvers are the most important features of the blast room ventilation system, which are ignored by many manufacturers.
Rolled M.S. sheet 10/12 swg ducting with dampers elbows & expansion joints connect the various dust extraction points with ﬁlter bag chamber. The dust collector unit is generally placed just near or behind the shot blasting plant. The length of intermediate ducting will depend on the general layout and location of the Dust Collector and hence the same is not considered in our present scope of supply.
For prevention of scoring of room enclosure walls, rubber sheets of low shore hardness are ﬁxed in a loosely hung manner. Abrasive particle hitting the rubber sheets looses its energy rapidly and falls down with minimum breakage and less scoring in the rubber sheet. The rubber sheet ﬁxing hardware includes specially formed 'Z' sections, and 'C' shaped ﬂat. The 'Z' member is ﬁxed to the wall through anchor bolts. Elongated punched holes in 'Z' section and 'C' channel make the ﬁxing of the rubber sheet with nuts and bolts very convenient. The 'C' Channel provides uniform pressure along the width of the rubber sheet and reduces chances of tear at the punched holes.