Pressure Blast versus Suction Blast
In the majority of applications, the Pressure Blast is favoured because of it's speed and versatility. The pressure blast is a system in which the abrasive is in a closed pressuresed vessel (blast pot) with one hose carrying a mixture of compressed air and abrasive from the blast pot to the nozzle. The suction blast is a system in which two hoses, one for compressed air and one for the abrasive, are connected to a gun which has a nozzle and an air jet.
Advantages of Pressure Blast:
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Faster - about 3 times faster than suction blast. |
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Particle velocity range - many pressure blasts are designed to operate from 15 to 125 psi. |
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Control of abrasive flow rate - the abrasive valve and the choke valve permit accurate control of the abrasive flow rate. |
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Operator fatigue - Reduced pressure blast nozzles are more compact and lightweight. |
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Maintenance - There are no air jets or gun bodies to wear out. |
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Longer abrasive life - Blast cleaning at high pressure greatly reduces abrasive life. |
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Pressure blasts throw more abrasive but at low pressure. |
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The abrasive breakdown per unit cleaned is reduced. |
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Can clean cored spaces. |
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Higher particle velocity - Critical in getting "bite" on a blast cleaned metal surface. |
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Nozzle Variety - Can use special nozzles such as angle nozzles |
Advantages of Suction Blast:
Lower price - Pressure blast cabinets usually cost more than suction blast cabinets of similar size.
Shorter Abrasive Change Time - Most suction blast cabinets are designed so the abrasive can be changed in 1 or 2 minutes. Most pressure blast cabinets require 5 to 10 minutes.
Quicker recycling of Abrasive - In suction blast cabinets, the abrasive is continuously re-cycled without interrupting the blast. In a pressure blast cabinet, the spent abrasive in the hopper will re-charge into the blast pot via the automatic fill valve after blasting stops, about 20 seconds.
In a choice between pressure blast and suction blast where pressure blast can give 3 time faster production, profit argues very strongly in favour of pressure blast.
