How to promote the innovation and development of production technology of fire door manufacturers

The speed ratio of low-speed diesel engine is generally, so when the fire door manufacturer adopts direct propulsion, it is not easy to obtain low speed. When the rated speed is, the stable low speed cannot be lower than. These ships have several loads with similar capacity but not used at the same time, such as the propeller and sludge pump of self-propelled dredger, the propeller and balance water pump of train ferry, etc. their driving motor armature is connected in series in a main circuit and powered by a public generator set, which can reduce the device capacity of the generator set. When the constant current system is adopted, it also has the points of fast motor transition process, reliable operation, flexible operation and no overload hazard of the system ⑤ locked rotor. When the propeller is stuck by rope, cable and ice, due to the use of electric propulsion, the system has locked rotor, and the motor is continuously switched on in a short time. When the reason for the jam is found, the propeller will quickly return to normal operation, The disadvantages of frequent disconnection and connection of the system are avoided. The total power of the propulsion device can be shared by several units, which increases the flexibility of equipment selection and improves the vitality of the ship. When direct propulsion is adopted, generally, one propeller is driven by two sets of diesel engines that provide the power required for ship propulsion.

When electric propulsion is adopted, the propeller can be powered by two or more prime movers: more than two diesel generator sets, which will bring some obvious benefits. For example, ① fire door manufacturers can use few types of diesel engines to obtain more power levels, thus increasing the flexibility of equipment selection; ② it is conducive to improving the vitality of the ship and the economy at intermediate navigation speed. When the sub units are damaged, other units can still work as usual and have strong vitality: when it is only necessary to sail at a lower speed, the sub units can be cut off to make the remaining units work at full load rate, obtain higher efficiency and improve the economy of operation. Medium and high speed non reversing prime mover can be adopted. The speed of propeller can not be too high, usually below, otherwise its efficiency will be reduced. Therefore, in direct propulsion, if the prime mover is a diesel engine, its speed can not be high. The so-called heavy-duty low-speed diesel engine has to be used, which is characterized by low power and speed. Due to the low speed, the quality is.

If the electric propulsion device is used, the light medium and high-speed diesel generator set can be used, and the reversible high-speed diesel engine is not used, which has light weight and small size, which is convenient for cabin layout; The non reversing diesel engine has the advantages of simple structure, reliable operation and long service life. When other conditions are the same, the service life of non reversing diesel engine is much longer than that of reversing diesel engine. According to relevant data, the wear of diesel engine every reverse rotation is equivalent to its working wear: the maintenance, management and overhaul of medium and high-speed diesel engine are relatively simple, and the replacement is also relatively convenient. Because the prime mover does not reverse, the electric propulsion device also creates a good environment for the wide application of gas turbine. There is no hard connection between the prime mover and the propeller. It can prevent shock and vibration and is conducive to noise reduction; The propeller speed can be selected without being affected by the prime mover speed; The diesel engine speed can also be selected, which is not affected by the propeller speed; The length of the main shaft can be shortened, which can make the arrangement of power equipment more flexible. The traditional electric propulsion device generally refers to the device that uses electric machinery to drive the propeller to drive the ship. Ships using electric propulsion devices are called electric propulsion ships or electric ships.