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 blowers are available in cordless, gas, and electric-powered models. Cordless Featuring rechargeable batteries, cordless models are ideal for use in tight spaces where you need freedom to move or for small yards.
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.