(A) has been used for general overhead crane lifting molten metal should be replaced in order to comply B/T7688.15-1999 "metallurgical casting crane crane technical conditions" requirement casting crane. If the plant, infrastructure and other factors do not have the conditions for replacement casting crane units, in addition to general overhead cranes meet regulatory norms and standards, must be transformed to the original crane technical conditions and meet the following basic requirements:
1 using metallurgical lifting special motor, when the ambient temperature exceeds 40 ℃ occasions, should be used in Class H insulation of the motor;
(2) equipped with two sets of brakes independent role (dual braking);
3 must be installed from the weight limiter;
4 equipped with different forms (usually hammer and rotary and use) the rising limit position of the double stopper (double limit), and should control the different disconnect device, lifting height greater than 20m crane, also should be installed according to need down limit position stopper;
5 with SCR stator voltage, eddy current brakes, power brakes, SCR power supply, DC power supply units as well as other as governor overspeed governor may cause lifting mechanism for lifting and 20t molten metal above the common overhead crane must have overspeed protection;
6 hoisting mechanism should have a positive and negative contactor fault protection features to prevent loss of power while the motor is still energized leading to brake stall occurred;
7 All electrical equipment shall meet the protection requirements of the relevant standards;
Eight long-term work in high temperature environment lifting its electronic control device needs to take protective measures;
9 Select the rope for high temperature applications, and has sufficient safety factor;
10 Do not use cast iron pulleys;
11 cranes working level is below the original A6 (not including A6), should be down load use, a decrease should be based on the actual work situation may be, but after derating required from the weight of the original nominal weight does not exceed 80%.
(Two) has been adopted for the nominal weight of more than 10t with electric hoist as lifting mechanism of various types of lifting machinery, lifting the molten metal is not allowed.
(Three) has been adopted for the nominal weight of less than or equal to 10t electric hoist as lifting mechanism of various types of crane lifting the molten metal, the original crane must be replaced or modified to meet the following basic technical conditions and requirements:
1 shall not be used as ordinary electric hoist lifting mechanism;
(2) with support for brake and safety brakes;
3 with the rise of different forms of double stopper (lifting height greater than 20m crane down limit position should be fitted stopper);
4 has a starting weight limiter;
5 with high temperature insulation protection feature electric hoist;
6 with lifting molten metal working conditions sufficient safety factor, the working class to achieve M5 class (including M5 level) above;
7 Select the rope for high temperature applications, and has sufficient safety factor;
8 as far as possible away from heat sources such as remote control mode must be set for operator safety channels.
(Four) the transformation of the crane must be licensed qualified unit transformation, the transformation must fulfill the formalities, after the transformation of the crane, must be approved by a qualified inspection agencies in accordance with the "rules of supervision and inspection of lifting machinery" and claimed herein oversight examination, qualified only after put into use in accordance with regulations.
(Five) of molten metal crane lifting the transformation should be done in June 30, 2008 to complete, using the replacement unit should immediately formulate plans or rehabilitation programs, and carry out, or should stop using it. During the implementation of the transformation, the use of units shall monitor use, must take effective measures to ensure the safe operation of equipment.
(Six) of molten metal crane lifting periodic inspection cycle from two years to one year.
