In 2009, the National Commission on Teaching and America's Future reported that in 18 states, including Connecticut, more than an half of the public school teachers were 50 or older, with the average teacher retirement age that year at 59.
Leaf Blower Types. Handheld: Handheld leaf blowers are the most common type for people interested in cleaning up leaves around a home. Backpack: Backpack leaf blowers are ideal for commercial or heavy-duty uses. Blowers with leaf vacuums: Some types of leaf blowers can convert into vacuums. This gives people the option to pick up and mulch light debris. Walk-behind blowers: Walk-behind blowers are ideal for heavy-duty cleanup jobs.
Figure I: Roots blowers have higher efficiency at moderate compression ratios. ratios. They are either of centrifugal types, axial flow types or regenerative types. As their internal clearances are relatively high, the discharge pressures are limited to few inches of water only. These types are generally used for applications requiring high volumes but low pressures - such as in air-conditioning, in furnaces, low pressure cooling, dust or fume extraction systems, lean phase pneumatic conveying etc. Positive displacement blowers (Roots blowers) Twin lobes and three lobes type blowers fall under this category.