| 摘要 |
PROBLEM TO BE SOLVED: To provide a screed heater which can reduce working load and worker's load and prevent overheat of a screed and also prevent acceleration of wear of the screed due to overheat and hence, prolong the life of the screed and always obtain a uniform leveled face until a work is completed as the temperature of the screed can be continuously kept in an optimum value even if an operator does not always pay his attention regarding the temperature control of the screed. SOLUTION: When a time preset in a timer of an electric source-on delay timer has elapsed, as a b-contact is opened and an electromagnetic opening/ closing valve 2 is closed, and supply of fuel passing a passageαis suspended, the fuel supply to a combusters 5a-8a is reduced to a specified volume passing a passageβand heated air volume is decreased. After a time elapses, a-contact is closed and a resistance is electified. the rotational frequency of fans 5c-8c is reduced and the blast quantity decreases proportional to decrease of the heated air volume. That is, when a time which has been preset in a timer has passed, the blast quantity decreases together with generation of heated air volume and the screed is automatically changed over from a heated condition to a heat-retaining condition.
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