4.3 Fills or Packs

Cooling tower fills or packs have been developed from the simple timber or bamboo splash bar to the modern vacuum formed or injection molded plastic fills now in common use according to Mirsky. Fills should be structurally strong, chemically inactive, fire resistant, resistant to fouling and erosion, and have a low airflow resistance. A critical comparative study is presented by Monjoie. His main objective is to identify the deficiencies of seven different plastic fill materials. Among others, properties concerning forming, assembly, fire, chemical, thermal, recycling, and environmental impact are evaluated. Examples of some plastic fills are shown in Figure 4.3.1.

Figure 4.3.1: Plastic Fills and Spray Nozzles (1) Film (2) Trickle Grid (3) Film (4) Splash (5) Spray Nozzles

Further examples of fills are shown in Figure 4.3.2 from Lowe and Figure 4.3.3 from Johnson. Many other configurations find application in practice according to Dumitru. PVC can be used as fill material up to a water temperature of about 50 C, chlorinated PVC (CPVC) up to 65 C, while Burger finds higher temperatures require polypropylene or stainless steel.

Figure 4.3.2: Fills (a) (b) and (h) Splash, (c) (d) (e) (f) (g) and (i) Film

Figure 4.3.3: (a) Fills

Figure 4.3.3: (b) Fills

In some applications, fill materials that can be recycled may be preferred. Many of the deficiencies of plastic fills may be avoided by employing stainless steel fills, an example is shown in Figure 4.3.4.

Figure 4.3.4: Expanded Metal Fill

The water distribution system for...