Industrial Overview
Calculating **Abrasive Consumption** is vital for project bidding and logistics planning in shipyards and refineries. Media usage is determined by two primary technical variables: **Nozzle Orifice Diameter** and **Operating Pressure (PSI)**. As a nozzle wears and its bore increases, abrasive consumption rises exponentially, impacting the project's bottom line.
Hourly Consumption (Kg/Hr)
| Nozzle Size | 80 PSI | 100 PSI | 120 PSI |
|---|---|---|---|
| 5 mm (#3) | 120 kg/hr | 150 kg/hr | 185 kg/hr |
| 6.5 mm (#4) | 210 kg/hr | 260 kg/hr | 310 kg/hr |
| 8 mm (#5) | 340 kg/hr | 420 kg/hr | 500 kg/hr |
| 9.5 mm (#6) | 510 kg/hr | 630 kg/hr | 750 kg/hr |
| 11 mm (#7) | 720 kg/hr | 890 kg/hr | 1050 kg/hr |
| 12.5 mm (#8) | 950 kg/hr | 1180 kg/hr | 1400 kg/hr |
*Values based on Garnet (Mesh 30/60). Usage will vary for Steel Grit and Aluminum Oxide (+/- 15%).
The Pressure Factor
Increasing pressure from 100 to 125 PSI can increase cleaning speed by 25%, but it also increases abrasive consumption and nozzle wear. High-pressure blasting requires precision **Abrasive Metering Valves** to maintain the technical air-media ratio.
Nozzle Wear Impact
A nozzle that has worn just 1.5mm larger than its original bore will consume 30% more abrasive per hour. For continuous projects, switching to **Boron Carbide (B4C)** nozzles is the primary strategy for media cost control.
Frequently Asked Questions
How is abrasive consumption calculated for sandblasting?
Abrasive consumption (kg/hr) is calculated from nozzle orifice diameter and operating pressure. Formula: kg/hr = (D² × P × K) where D = nozzle bore in mm, P = pressure in bar, K = abrasive constant (copper slag: 0.27, garnet: 0.21, steel grit: 0.35). A #8 nozzle (12.7mm) at 7 bar consumes approximately 340 kg/hr of copper slag. Use actual consumption charts for accurate project estimation.
What is the cost per square meter for different abrasives?
Cost per m² = (Abrasive price per MT / Reuse cycles) / Coverage rate. Copper slag: ₹8-15/m² at zero reuse cycles. Garnet: ₹15-30/m² at 5-8 reuse cycles. Steel grit: ₹20-40/m² at 100+ reuse cycles in blast room. For large blast rooms (>500m²), steel grit and garnet are most economical. For field work, copper slag is most cost-effective.
How does nozzle wear affect abrasive consumption?
As a nozzle bore wears from new to 25% larger, abrasive consumption increases by 60-80% for the same pressure. A #6 nozzle worn to #8 bore consumes as much abrasive as a genuine #8 nozzle. This makes nozzle wear monitoring critical for abrasive economy. Replace nozzles when bore exceeds 125% of original size.