Aludur® grid bar systems, developed by Saint-Gobain NorPro over 60 years ago, include the following benefits:
- excellent thermal stability
- lower pressure drop or greater hydraulic capacity
- exceptional mechanical strength
- resist all alkalis, solvents, and acids (except hydrofluoric acid)
- maintains its excellent chemical resistance at temperatures well beyond the limits of standard ceramic (it should not be used in systems where the bars will be exposed to superheated steam for an extended period of time)
The superior qualities of Aludur® formulation permit the use of thinner bars and greater center-to-center spacing. At 83% open area, our grid bar systems far exceed that of typical supports and work equally well with stacked or dumped packing. When used with dumped packing, a secondary layer of grid blocks or cross partition rings on top of the primary support bars is recommended. While maximum individual bar length is limited to 84 in. (2.13m), grid bars may be used in towers of any diameter through the use of mid-span supports. Bars are factory-cut to custom lengths to create the complete grid bar support assembly.
Grid bar support assemblies can be designed for two standard installations: 8 in. centerline bar spacing for use with Proware™ grid blocks as secondary packing support, or 6 in. centerline bar spacing for use with Proware™ cross partition rings as secondary packing support. At 83%, the open area of an Aludur® grid bar system far exceeds that of typical dome supports. This greater open area means lower pressure drop or greater hydraulic capacity.
Aludur® Typical Physical Properties
| Acid Resistance | < 3.0 wt% |
| Water Absorption | < 0.4 wt% |
| Flexural Strength (10-in. bar) | 8000 psi |
Nominal 8-in. bars -- properties
|
8.3 in. (210mm) |
Nominal 10-in. bars -- properties
|
10.4 in. (264mm) 1.4 in. (35mm) 84 in. (2134mm) max 10-in. bars on 8-in. spacing (122 kg/m2)
|
Aludur® Typical Chemical Composition
| Al2O3 | 76% |
| SiO2 | 20% |
| Balance | MgO, CaO, TiO2, Na2O, Fe2O3, K2O |
Saint-Gobain NorPro’s Grid Blocks and Cross Partition Rings are made with our Proware™ ceramic formulation ensuring superior performance with Aludur® support assemblies.
Proware™ Grid Blocks should be used for secondary support with bars placed on 8 in. centers. Grid bars with NorPro® grid blocks also have 15% more free space than a conventional 6 in. center installation using cross partition rings. The square stacking pattern of Proware™ grid blocks layered above Aludur® grid bars provides 72% open area. Proware grid blocks will retain 50mm (2 in.) saddles.
Proware™ Cross Partition Rings should be used as secondary support with bars placed on 6 in. centers. An additional layer of 4 in. rings is required to ensure retention of 2 in. saddles above. Proware cross partition rings are manufactured in 3 in. (80mm), 4 in. (100mm) and 6 in. (150mm) diameters.
Grid Block Typical Physical Properties
| Block Dimensions | 8.5 in. L x 5.75 in. W x 3.5 in. H (216mm L x 146mm W x 89mm H) |
| Weight per Tower Area | 94 kg/m2 |
| Acid Resistance | < 4.0 wt% |
| Water Absorption |
< 0.4 wt% |
| Leachable Iron | < 0.01 wt% |
Each block typically weights 6.1 lbs. (2.77kg) and when installed occupies an area of approximately 46 in.2 (297cm2). Generally, 5-8% spares are recommended to allow for cutting at the tower wall.
