Mud pump crankshaft connecting rod bearing design and installation
Published: 2015-01-16 09:57:23
During the installation process, machinery and equipments had usually single machine debugging, and debugging with other machines, its purpose is to verify the reliability of the equipment when working normally, but they often have to face a lot of unexpected anomaly in the practical work. In the actual work, we have to make effective analysis and processing for these "anomalies" and then make the operation of mechanical equipment installation works normally.
1. Brief introduction of mechanical equipment installation
The installation of mechanical equipments means that after they were transported to the construction site by the factory, installed correctly to a predetermined position with the aid of some tools and instruments, through necessary works, through the debugging and they can achieve the operation.
A mechanical device can smoothly be put on production or not, can give full play on its performance or not and prolong the service life of equipment or not and improve the quality of the product or not, it largely depends on the quality of the mechanical equipment installation .
(1) The general process of mechanical equipment installation
All kinds of mechanical equipment installation process generally must include: lifting transportation, unpacking inspection of equipment, pay-off in place, fixed, cleaning, assembly of parts and adjustment of parts, commissioning and acceptance of project etc. The difference is that the different mechanical equipment need to adopt different methods in the process of these woke.
For example, during the installation process, the large equipments take the method of fission installation, while for small equipments adopt the overall installation method.
(2) The content of mechanical equipment installation
It mainly includes hoisting and transportation of the equipment, the whole and parts assembly of machinery and equipments, the installation of pipe fittings, cutting and welding, the assembly of all kinds of container internal components, the installation of motor, installation and debugging of instruments and meters and automatic control equipment, testing start-up and commissioning work.
(3) Requirements of mechanical equipment installation
Firstly, we must strictly guarantee the quality of equipment installation and have a correct construction according to design drawings, equipment structure, installation instruction and acceptance standard of construction, quality inspection standards and procedures. Secondly we need to adopt scientific methods, speeding up the construction schedule, ensuring to product on schedule.
Design And Installation Of Mud Pump Crankshaft Connecting Rod Bearing
Second: Debugging in the process installation of mechanical equipment
1.Bearing Temperature is too high
There’s three reasons which lead high temperature of blower bearing: poor lubrication, cooling not enough, abnormal bearing. Centrifugal fan usually located out of the fan bearing,.If appears desquamate, hemp pit,it can lead high temperature. Generally it can be judged by listening to sound of bearing and measuring methods of vibration. If lubrication and cooling is not enough,it can be visually inspected such as fingerprint method of intuitive judgment. Axial flow fan bearing has focused on the bearing box, placed beneath the inlet chamber, the high bearing temperature at the time, because the fan running, it is difficult to judge bearing has a problem or lubrication, cooling problem. In the operation of the actual debugging should first solve the problem from the following several aspects.
First, if refueling is appropriate according to the manufacturers instructions and specified requirements. Sometimes also can appear high temperature after bearing oiling , mainly as oil too much. This phenomenon for temperature rising continuously, after reach a certain point (usually in higher than normal operating temperature 10 - l5 ℃) will remain unchanged, and then gradually decline.
Second, the cooling power is not enough. Smoke temperature in induced draft fan is 120-140 ℃.bearing box temperature will rise if there is no effective cooling. The solution of simple and economical is set up in lateral wheel hub bearing compressed air cooling. When the temperature is low can not open compressed air cooling, open the compressed air cooling at high temperature. Confirm there is no the problem then check the bearing box again.
Bearing Vibration
Fan bearing vibration is common faults in the operation. The vibration of fan will cause damage of bearing, blade, bolt looseness, chassis and wind damage, seriously endanger the safety running of fan.
Vibration fan caused by fan itself, in general the vibration source from itself. Such as inhomogeneity of moving parts material; rotor unbalance of quality caused machining errors; Bad quality of installation and maintenance; Fan running the unhealthy when load changes; Rotor, wear or damage to the front and back guide blade wear, deformation; The baffle opening adjustment does not reach the designated position; Bearing and bearing fault, and so on.
It can produce vibration in fan under the small disturbance force. In the operation process, it is necessary to taking a series of corresponding measures to reduce or eliminate vibration, such as taking wear processing of fan impeller and guide blade, bearing using high quality products, Bearing box and pipe end plate connection high strength bolt taking locking measures, taking process in support of core tube, increasing brace. Taking strict inspection and improving vibration inspection device of fan.
Air duct system vibration cause the vibration of the fan duct. This is an easy to overlook in production. Vibration will change as in and out air volume.The lower part of the general diffusion cell only 4 to stand, and on the other side of the joint asbestos canvas is soft joints. It makes the whole diffusion cell suspension is the 60% of the weight bearing. Aiming at this situation, under the diffusion tube outlet add a fulcrum, can rise to fall can move. When the load change, only need to fine-tune the fulcrum, can eliminate the vibration.
Mud pump crankshaft connecting rod bearing design and installation(3)
3.Surge
In the process of wind turbine, when flow reduced to Q min value, the flow entering the cascade separation occurs,it in the separation zone along the impeller rotation direction and moves at the rate of smaller than impeller rotating angular velocity, which is rotating.When rotating from spread to the whole passage, fan outlet pressure suddenly drops sharply, but the pressure in the pipe network don't reduce immediately, so the pressure of pipe network is greater than the fan outlet , the gas of pipe network pour into the fan, until the pressure fall below the fan outlet pressure of pipe network.Then the blower started to gas to the pipeline, the refluent gas press out, which in turn reduce the flow, the pressure of blower suddenly drops again.The gases in the network go back to the draught fan. Throughout the system it produces a cyclical low frequency and high amplitude of pressure fluctuation and flow oscillation phenomenon, that made a lot of noise, severe vibration of the machine till it not work, this is surging.
1, Listen to the air blower noise of gas pipeline.When approaching surge condition, the noise from the air in the vent pipe is high low, and produce periodic changes.When entering the surge condition, noise increase immediately, even has blown.
2, the observed changes in fan outlet pressure and inlet flow.When the normal work, outlet pressure and inlet flow change is not big, when entering surge, the changes are very big.
3, observing the vibration of the body.When entering the surge, the body strong vibration and bearing will occur. The main method to prevent surging is adopt the bleed air duct.Setting the by-pass pipe on the duct, once air volume reduced to Q min value, the by-pass pipe valve automatically open air.At the same time the import traffic increase, working point can be made of surge area to the stable work, thereby eliminating the inlet flow rate is small, Angle of attack is too large to cause the possibility of stall and surge.When using the inlet guide blades adjust air volume, as the condition change, guide vane rotation change channel area to meet the requirements of new conditions and to avoid airflow stall, which can effectively prevent the fan surge.
4.the move leaves unsmooth
Axis wind flow regulation of motor leaf is through the drive mechanism drives the slide valve to change the hydraulic cylinder oil pressure difference on both sides.In the operation of the axial flow fan, can appear the phenomenon of moving blade adjustment difficulties or not adjustment. Appear this kind of phenomenon is usually considered to be fan regulation oil system failure and the adjusting mechanism for the wheel hub internal damage, etc.But in practice often is another reason, in the wind has a certain gap between blades and hub in order to realize the moving blade Angle adjustment, but scale caused by incomplete combustion of carbon or dirt jam gap formation dynamic adjustment difficulties. Moving blade unsmooth phenomena is common in fuel boiler and the water film dust removal of boiler ,mainly measures are:
(1).In the operation of the debug make fuel oil or coal combustion fully reduce the carbon black, raise the temperature of exhaust smoke and inlet air, avoid the sulfur in flue gas condensation in the air pre-heater.
(2).In the impeller import setting steam purging pipes, when fan downtime to sweep of the impeller, keep the impeller cleaning, steam pressure ≤0.2Mpa steam temperature ≤200℃
Modern industry development is rapid and have many special condition soneed to use all kinds of non-standard bearings. Our company designed for a mud pump crankshaft connecting rod bearing is a kind of special structure. Mud pump work by gear transmission, the crankshaft rotates.By means of the connecting rod connected to the crankshaft and the piston,driving a piston reciprocating motion,and realizing the pump work.
The design and installation of mud pump crankshaft rod and crankshaft bearing (4)
Crankshaft bearing
It can be seen that when the piston is having the reciprocating motion, there is a larger radial impacting load, thus cylindrical roller bearing is needed on the crankshaft , which can withstand the bigger radial impacting load. Due to the limitation of the crankshaft structure, the whole bearing can't be installed, so we need to adopt the bearing with dissection structure or adapter sleeve. We can see from figure 1, there is no positioning device in bearing cooperation to position bearing and also it is unable to tighten bearing, so the four row cylindrical roller bearing is needed. Bearing diameter is increased, and made of cone hole structure for easy installation. Adapter sleeve is two-body structure, after it puts successively bearings components into the matching surface of crankshaft assembling into bearing, the two half - adapter sleeve is put into crankshaft bearing inner cone cooperating with it, with a lock nut locking, fixing bearing on the crankshaft. The whole installation is easy and simple.
The mud pump works after a period of time, sleeve will be meshed with bearing inner surface. When repairing or replacing bearings of equipment, it is difficult to remove the bearing. so we need to add oil access in the design of adapter sleeve, ( chart 2), high pressure oil was pressed in from the oil inlet, forming hydraulic oil film in the mating surfaces through oil access, reducing friction resistance, bearing removal easily, so tight sleeve can be used as withdrawal sleeve.
2. The piston bearing
In the joint where piston and piston rod are connected, radial section is small. not only bearing can be demanded to withstand the bigger radial load, but also have a simple structure, be compact, be convenient to be disconnected, so the four row cylindrical roller bearings are needed. Seeing from figure 3, outer steel ring and roller are treated as outer components. Cylindrical pin is treated as a bearing inner ring. This can save a space, increase the diameter of roller, improve the bearing capacity. Cylindrical roller bearing has a low friction coefficient in another way, the high manufacture precision, convenient disassembling, easy maintenance and replacement.
Due to the serious environmental pollution bearing working in, we want to prevent sand and dust from being into mud bearing and affecting its service life. So we need a dust cover on both ends of the bearing, forming a closed sealing, to ensure the normal working of bearing.
The results of user's actual application show that the two types of bearings are accorded with the usage of the scene and has a good reliability and can satisfy completely the requirements of production. Third, timely adjust the opening of the moving blade to prevent blade causing the scale formation in an opening degree for a long time. After motor shut down, the moving blade should have a activity continuously in 0 ~ 55 °. Fourth, check rotor drive mechanism often and add lubricating oil appropriatly.
All in all, with the improvement of China's machinery manufacturing level, the performance, efficiency and reliability of all kinds of mechanical equipments are catching up with or exceeding similar foreign products, but there is still more trouble s in the practical test and operation situation. Perfecting the system design, ready for all kinds of woke before debugging, paying close attention to mechanical equipments and the anomaly in the operational process, strengthening the maintenance work is the key to enhance the reliability of mechanical equipment.
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