The bearing points of No. 3 and No. 4 on both ends of the low-pressure outer cylinder of the induction unit are designed on the inner edge of the inner beam of the bearing base to form a cantilever support, which results in a softer stiffness. The bearing support of No. 3 and No. 4 is a flexible support. The design of the No. 4 bearing is too large, and the unit bearing pressure is about 24kg/cm2. The vacuum is used to change the bearing height. After the generator is charged with hydrogen, the bearing's elevation also sinks, directly affecting the load of the No. 4 bearing. It shows that the vertical direction dynamic stiffness of the No. 4 bearing seat is significantly smaller than that of the No. 3 bearing seat. Therefore, the manufacturer has improved the No. 4 bearing seat to improve the support stiffness, but the effect is not obvious, especially when the second-order unbalance of the low-pressure rotor is large, 4 The abnormal vibration of the bearing is very prominent. The second-order critical speed of the low-pressure rotor support system of the unit is close to the working speed, which makes the vibration sensitive to the unbalanced excitation. The low-pressure No. 4 bearing of the Dongfang 300MW steam turbine also has similar anomalies. Common problem of vibration.
The abnormal vibration treatment method caused by this type of fault is mainly based on the characteristics of the flexible support and the vibration characteristics of the rotor to accurately and high-speed dynamic balance of the low-pressure rotor, so that the vibration can reach an excellent level. Unstable three-bearing rotor imbalance The abnormal vibration caused by this type of fault often occurs in the startup of new machines or after the overhaul of the unit, and it is also the most difficult to handle. Because the unbalanced distribution of the generator rotor and the alignment of the shafting are different, the vibration performance characteristics of the unit are different and the processing methods are different.
With the continuous development of drilling production, the use conditions of drilling rigs have become more and more diversified, and various types of drilling rigs have appeared accordingly. Factors affecting the type and composition of drilling rigs include drilling method, drilling depth, borehole size and drilling tool size, and drilling area conditions (such as electricity or fuel, transportation, and meteorological conditions).
1. According to drilling method
(1) Impact drilling rigs, such as wire rope impact drilling rigs (drilling rigs), vibration drilling rigs, etc.
(2) Rotary drilling rigs, such as those used in rotary drilling.
(3) Downhole power drilling tools, such as rotary drilling tools, turbo drilling tools, screw drilling tools, electric drilling tools, etc.
2. Divided by drilling depth
(1) Ultra-deep well drilling rig. It adopts a drilling rig with a diameter of 114 mm drill pipe, a nominal drilling depth range of more than 7000 meters, and a maximum hook load of more than 4,500 kN.
(2) Deep well drilling rig. The drill rod is 114 mm in diameter, the nominal drilling depth is 4000-7000 meters or more, and the maximum hook load is 2250-4500 kN or more.
(3) Drilling rigs for medium and deep wells. It adopts a drilling rig with a diameter of 114 mm drill pipe, a nominal drilling depth range of 1500-4000 meters or more, and a maximum hook load of 900-2250 kN or more.
Three, according to power equipment
(1) Diesel Engine-driven drilling rigs, which use diesel engines as power through mechanical transmission or hydraulic transmission.
(2) AC driven drilling rig, suitable for use in oil fields with industrial power grids.
(3) The drilling rig is driven by direct current, and the working unit is driven by a direct current motor.
Fourth, according to the driving mode
(1) Drive alone. Each working machine is driven by generators of different sizes, which are mostly used for electric drive. The transmission is simple and easy to install, but the power utilization rate is low and the total equipment mass is large.
(2) Unified drive. The three working units of drawworks, drilling Pump and turntable are driven by the same power unit. Most drilling rigs use this scheme. The unified drive can also include only one drilling pump, and the other drilling pump is driven separately. The unified drive drilling rig has high power utilization and can be adjusted mutually when the engine fails, but the transmission is complicated, installation and adjustment are troublesome, and the transmission efficiency is low.
(3) Group drive. The combination of power is between individual drive and unified drive. There are two options for three working machines. The power utilization rate of this kind of drilling rig is higher than that of a single drive, and the transmission ratio is simple to drive in a unified manner. Two sets of working machines can also be installed on different heights and scattered sites.
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