Crankcase ExplosionWritten by Thomas Yoon
One of most frightening phenomenon for operators of diesel engines is crankcase explosion. Although many force-lubricated, totally enclosed, reciprocating machines like diesel engines, steam engines, air compressors and many others had been running for many hours without any such problems, still problem of crankcase explosion is ever present and we cannot forget about it. In order to understand phenomenon of crankcase explosion, we have to understand nature of fire, because, after all, an explosion is a very rapid propagation of fire. A fire will only start whenever three conditions are met: fuel, oxygen, and heat. A fire can very well start inside crankcase of a diesel engine when conditions are just right. For all recorded occurrences of crankcase explosions, one factor is common, namely a hot spot. That is heat source. Now, let us take a look inside crankcase. It houses crankshaft, connecting rod, piston rod, cylinder liner, piston, drive gears or chains and lubrication oil. To prevent lubrication oil loss, protect persons from moving mechanical parts, prevent contamination of oil, and many other reasons crankcase is totally enclosed and separated from external environment. First, let us look at moving parts. There is reciprocating mechanism consisting of crankshaft, journal bearings, and connecting rod. If it is a crosshead engine, crosshead sliding and reciprocating mechanism. For trunk type engine, there is piston and small end bearings. There are also gears or chains to drive camshaft. For reversible engines, reversing drive mechanisms. There is also thrust bearings at end of crankshaft to take up driven load. There may also be cooling oil pipes, or cooling water pipes sliding inside crankcase for piston cooling. The piston rod itself may also be sliding through a gland assembly at under piston space.
| | Satellite Radio: XM and Sirius Battle for Your $$$Written by Dale L
Satellite Radio is future of broadcastingSatellite Radio, in short, can be described as commercial-free music, news, sports and talk shows. Many of biggest players and events are now available from Sirius radio and XM radio like Howard Stern, Fred Schneider (the B52s), NFL, English Soccer, NBA, NASCAR, NHL, Major League Baseball, INDY, and PGA. Satellite radio began in 1992, when ‘S’ spectrum was allocated by FCC to four companies. The two main ones, Sirius and XM paid a pretty penny (in fact almost $80 million dollars worth) to buy a license. Satellite-based radio began on May 15th, 2001 when XM Radio completed their satellite system. Sirius followed shortly when they launched in July, 2001. Since then, expanded products and competition has changed radio landscape. While automobile manufacturers started installing satellite radio in 2001 and 2002, most new vehicles come equipped with one now. XM has two satellites (called ‘Rock’ and ‘Roll’) in parallel orbits to cover mainland US market, while Sirius has three. Both have recently been awarded licenses for Canadian market. So what are differences between two providers? XM has a flat $9.99 a month fee with no contracts to sign. They have latest portable equipment. XM offers some of best varieties of programming available today. They offer 68 commercial-free music channels; 32 channels of News, Sports, Talk & Entertainment; and 21 channels of instant Traffic & Weather in major metro areas. Here's latest information of channels: 15 channels of Rock music 11 News channels (Fox, CNN, ABC, CNBC, MSNBC, BBC, C-SPAN, Bloomberg) 11 Talk & Variety channels (Discovery, E!, Experts & advice, African American Talk, Christian Talk) 10 channels of Pop music & Top Hits 7 Country music choices 7 channels of Blues & Jazz music 7 Hip Hop and Urban music choices
|
