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Transcript of Smoke Detector
A smoke detector is a device that senses the presence of smoke in a building and warns the occupants, enabling them to escape a fire before succumbing to smoke inhalation or burns.
If you are indoors, raise your head
and you can find it.
In the late 1930s the Swiss physicist Walter Jaeger tried to invent a sensor to detect the poison gas, but he failed.
Frustrated, Jaeger lit a cigarette
A meter on the instrument had registered a drop in current. Smoke particles had apparently done what poison gas could not.
The detector really worked. The simple SD emerged at that time.
However, the smoke detector was so expensive on account of the restriction of materials. Although a large amount of public places demanded the SD to avoid fire, and to prevent the unnecessary loss, only the rich one could afford them.
After 30 years, it was 1960s, home smoke detectors were available, though the price
were still rather high. So only rich people can use them to warn the fire, and minimize their losses.
How did it emerge?
Only rich people were
able to have a SD
Everyone can have a SD now!
After the application in Skylab, a big progress in the solid-state circuitry emerged, the size of the detectors and their cost were significantly reduced. The first truly affordable home smoke detector was invented by Duane D.Pearsall in 1965. Design refinements, including more energy-efficient alarm horns, also enabled the use of common available sizes of batteries rather than the hard-to-find specialty batteries that had to be required previously.
Do you know some products
we use today that came from
Today we will talk about such a product --The Smoke Detector.
Do you know Chang'e-2?
China's second moon probe.
It was launched at 1, Oct.
The lab also need SD.
In 1970s, NASA engineers designed a space laboratory--SkyLab, but if the lab on fire, it would be a big trouble. As a result, NASA and Honeywell joint study for the space lab, and invented an adjustable sensitivity smoke detectors for fire alarm.
SMOKE DETECTORS FOR LIFE!
So, if one's house is equiped with smoke detector, then it may protect his/her assets, even save his/her life. It can make our life more secure, and we won't always worry about the fire.
Since 1991, the losses have risen slightly. Why?Experts say there are two reasons for losing so many lives. First, even though 7 out of 8 American homes has a smoke detector, it is believed that one fourth of them do not work, most because of dead or missing batteries. Second, those detectors installed in the 70's and 80's are aging. Detectors over 10 years old may not function correctly, even if they sound when tested.
Over and over each year, the tragic scene is played out: a fire often takes place in a house while the occupants are sleeping. Then, one or more people died because they failed to wake up in time to get out.In 1968, U.S. home fire deaths peaked at more than 6,000 lives lost.
Engineers can use the new energy such as Solar Energy to take place of the battery, then we don't need to change the battery for a long time. The sensitivity of the SD are also needed to develop according to the video.
New property of SD
Society changes every day, now in China, most people want to have a healthy life. So, the government of Shanghai decided to ban smoking in the public places from 1,Mar,2009. Then, some companies, restaurants begin to buy some SD to detect the smoke. It's an effective method to ban smoking. The new function of the SD are really useful.
Unfortunately, once a room suddenly gets on a big fire in accident, and the big fire created a large amount of smoke , the Ionization smoke detector wasn't work at all. It caused huge loss. Then, people wanted to have a new kind of SD. So a photoelectric smoke detector came out with its function that was able to detect a large amount of smoke. A photoelectric smoke detector measures the smoke of a confined space and activates an alarm in response to relatively large smoke particles generated by smoldering fires.
There are still many potential functions we haven't discovered.
And we can create more kinds of SD.
The development of SD won't stop!
Thank you for watching.
During the late 70's and the early 80's, more and more families began to install smoke detectors in their homes. Then, the numbers of death declined, to a low of 3,500 in 1991. The most recent figures available are for the year 1995, when 3,695 non-firefighters lost their lives in home fires in the USA, and at least 80% of those people were in homes without a working smoke detector.
Such as the famous theatre
Sometimes we thought that the cheap SD came from the 'Space'!
Protect their own assets, and lives.
Using the affordable SD
Using a SD
The engineers and the equipments in the Skylab.
If the lab is on fire,it'll loss a lot.Using an
adjustable sensitivity smoke detectors
Protect their own
assets,even their lives.
Using the less
They should avoid fire, and the customers demand a save environment.
Using the expensive SD