Mixing head small size

In anticipation of the above considerations, a small size RIM mixing head was developed, suited for small capacity operation. 

Figure 2 shows the specifically developed small size custom RIM machine for this application, including the metering unit, electrical controls, fixture for the vertical arrangement of the baseball bats to be filled, and also an up and down moving support on which the mixing head is installed. The operation of the machine is semiautomatic. 

Other uses of the new mixing head include the production of small size test samples on laboratory RIM machines for the development and evaluation of foam and non-foam RIM materials of different nature, encapsulation of electronic components, production of small size technical parts and the fill of small quantities of insulation foam in plastic picnic jars. 

Figure 1. Small size RIM impingement mixing head type "A/2". Diameter of mixing chamber 1/8" (3.175 mm).

Various rules of thumb exist for standard water filtration rates and cycle time before backwashing. Higher filtration rates may appear to be economically justified, however, when the filter loading is within conventional limits. In this example, we examine the issues involved for constant-rate filtration for a dual-media bed. Dual- and mixed-media beds result in increased production of water in a filter for two reasons. First, the larger grains (say charcoal approximately 1-mm size) as a top layer help reduce cake formation and deposition within the small (150-mm) top layer of the bed. Second, the head loss in the region of significant filtration is reduced. 

The last two free-energy contributions involve only the surfactant heads. The steric contribution, gst, accounts for steric interactions between the surfactant heads at the micellar interface. This contribution can be responsible for synergism in mixed micelle formation if the heads of the two-surfactant types have different sizes, as illustrated by the large grey heads and small black heads ii Figure 12.14. The steric contribution depends only on the size of the surfactant heads. 

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