Bevel-helical gearboxes B4 ension The direction of rotation is determined b B4-FH21A

Flender/Flender Gear Units/Bevel-helical gearboxes B4

with the product.For most products, the threshold concentration is 0.1 LL /H1and the maximum effect is achieved at 1 LL/H1or less. However, some treatments may use up to 1 LL/H1to adjust for leaky rooms. The source of ethylene can vary. Bottled ethylene gas is relatively inexpensive, but other sources may be preferred when bottled gas is not available or there is safety concern (ethylene gas is explosive at concentrations between 2.7 and 3 kPa). Ethylene can begenerated from commercial liquids that contain ethanol and possibly other proprietaryproducts. Heating of the liquid breaks down the ethanol and ethylene is produced.Ethephon (2-chloroethane phosphonic acid), commercially available under various tradenames, such as Ethrel, Florel, Cerone, Prep, and CEPA, is available in liquid form.When the pH of the solution is raised above 5, the ethephon molecule is hydrolyzed, releasing several products, one of which is ethylene. The rate of hydrolysis increases as the pH increases. Calcium carbide (Ca 2C), which exists as grayish solid, produces acety- lene and trace amounts of ethylene when hydrolyzed (. Acetylene has ethylene-likeeffects but it takes much higher concentrations, which increases the possibility of an explo-sion. This method is still popular in parts of the world where the other sources of ethyleneare not available or are more expensive (.., India) ( Upadhaya, personal communica- tion). Perhaps the simplest and cheapest way to add ethylene is based on the fact that there is wide range in the rate of ethylene production in plant products (. Therefore,ethylene can be added to storage by adding ripe plant products generating ethylene. Thismethod may be appropriate in small-scale commercial operations or in the home. 4.5 Ethylene Removal In many storage situations, it is important to remove ethylene to slow ripening and senes- cence. The simplest method to remove ethylene is to remove the source() and/or to venti-late the storage area with ethylene-f