Figure 7-1: Load Cell Performance Comparison | |||||
TYPE OF LOAD CELL | WEIGHT RANGE | ACCURACY (FS) | APPLICATIONS | ADVANTAGES | DISADVANTAGES |
Mechanical Cells | |||||
Hydraulic | Up to 10,000,000 lb | 0.25% | Tanks, bins and hoppers. Hazardous areas. |
Takes high impacts, insensitive to temperature. |
Expensive, complex. |
Pneumatic | Wide | High | Food industry, hazardous areas | Intrinsically safe. Contains no fluids. |
Slow response. Requires clean, dry air |
Strain Gage Cells | |||||
Bending Beam | 10-5,000 lb | 0.03% | Tanks, platform scales, | Low cost, simple construction | Strain gages are exposed, require protection |
Shear Beam | 10-5,000 lb | 0.03% | Tanks, platform scales, off- center loads |
High side load rejection, better sealing and protection |
|
Canister | to 500,000 lb | 0.05% | Truck, tank, track, and hopper scales | Handles load movements | No horizontal load protection |
Ring and Pancake | 5- 500,000 lb | Tanks, bins, scales | All stainless steel | No load movement allowed | |
Button and washer | 0-50,000 lb 0-200 lb typ. |
1% | Small scales | Small, inexpensive | Loads must be centered, no load movement permitted |
Other Types | |||||
Helical | 0-40,000 lb | 0.2% | Platform, forklift, wheel load, automotive seat weight |
Handles off-axis loads, overloads, shocks |
|
Fiber optic | 0.1% | Electrical transmission cables, stud or bolt mounts |
Immune to RFI/EMI and high temps, intrinsically safe |
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Piezoresistive | 0.03% | Extremely sensitive, high signal output level |
High cost, nonlinear output |