Components of drilling fluid centrifuge
Release time: 2015/11/26 Ai Yi NewsViews : 3194
Drilling fluid centrifuges are called horizontal spiral unloading sedimentation centrifuges and are widely used in industries such as oil drilling and drilling that require mud purification. The main structure of drilling fluid centrifuge is shown in Figure 1. There are two rotating parts concentrically mounted on the same bearing in the casing, the drum is on the outside, and the conveyor with spiral blades is interviewed on the inside. The motor drives the drum to rotate through the triangle pulley wheel. The drum is connected to the outer casing of the planetary differential through the left bearing. The screw conveyor and the drum are driven to rotate in the same direction by the output shaft of the drilling fluid centrifuge differential. , But the speed is different, there is a slip rate.
1. The main component of drilling fluid centrifuge-rotating drum <br /> The rotating drum of drilling fluid centrifuge is generally composed of a rotating drum body and a large and small end cover (also a regulating device). The tapered part of the rotating drum body is easy to wear. To reduce wear, several ribs are added along the line, as shown in Figure 2.
There is a pivot on the big end of the rotary drum of the drilling fluid centrifuge to support the main bearing. The pivot is connected to the rotary drum through a flange. The end cap is provided with an overflow port, and the other end has a small end cap connected to the small end and supported on the bearing.
The position of the overflow port at the large end of the drum is adjustable, thereby controlling the different depths of the liquid pool. It has a large impact on the production capacity and clarity of the drilling fluid centrifuge, and should be adjusted according to different process requirements. The distribution of overflow ports at the overflow end of the drum is shown in Figure 3.
There are various methods for adjusting the overflow port. An overflow baffle is usually installed at different positions to adjust the depth of the liquid pool. When it is required to increase the depth of the sedimentation pool, the shallow liquid layer and the medium liquid layer are blocked, at this time, the residence time of the drilling fluid in the pool in the sedimentation zone is extended, and the separation efficiency is improved. When the pool deepens, the dehydration zone is relatively shortened, which will cause the moisture content of the mud cake to rise. The screw conveyor of the drilling fluid centrifuge is driven by the output shaft of the differential. When the sedimentation load is excessive or the spiral blades are stuck, the differential will be damaged. For this reason, the spiral drilling fluid centrifuges of various structures are provided with overload protection devices, which can automatically cut off the power supply of the motor and stop feeding to prevent accidents.
The representative parameter of the drum of a drilling fluid centrifuge is its maximum inner diameter. The inner diameter of the drum has been serialized. The larger the diameter, the greater the production capacity of the drilling fluid centrifuge. For example, LW533 drilling fluid centrifuge indicates that the inner diameter of the rotating drum is 533mm. In addition, the drum length and drum diameter ratio (length-to-diameter ratio) determine the dehydration residence time of suspended particles of drilling fluid inside the centrifuge. The larger the ratio, the drier the solid particles separated.
In recent years, with the advancement of machinery manufacturing technology, the aspect ratio has gradually increased. The production of low-concentration suspensions that are difficult to separate mainly depends on the peripheral speed and the aspect ratio of the drum. Since the aspect ratio is greater than 4, it is difficult to manufacture In addition, it is necessary to increase the diameter at the same time, but increasing the diameter will affect the dynamic balance and other related characteristics of the drilling fluid centrifuge when it is working. Therefore, for suspensions that are difficult to separate, the best method is to increase the aspect ratio under the condition of small diameter. Only when the output cannot be guaranteed, can the diameter of the drum be increased.
2. The main component of drilling fluid centrifuge-screw feeder <br /> The screw feeder of drilling fluid centrifuge consists of rotating blades, inner cylinder, feeding compartment and left and right journals, as shown in Figure 4.
Wear-resistant measures are taken on the surface of spiral blades, such as spraying wear-resistant alloys and wear-resistant plastics. The screw pusher of the drilling fluid centrifuge produced by Aiyi Machinery is made of ceramic or high hardness wear-resistant alloy.
3. Main components of drilling fluid centrifuge-overload protection device <br /> The main motor of the drilling fluid centrifuge provides the separation power, and also provides the power of the screw conveyor. The planetary differential may be destroyed when the amount of sediment that is delivered exceeds the limit of the planetary differential, or metal foreign matter falls into the drum and jams the spiral. In order to prevent the screw and the differential from being damaged, the drilling fluid centrifuges produced by Ai Machinery are equipped with special overload protection devices. Overload protection devices include mechanical, mechanical hydraulic, electronically controlled mechanical and electrical overload protection devices. Among them, the most commonly used are mechanical.
4. Transmission device of drilling fluid centrifuge <br /> The transmission device of drilling fluid centrifuge generally adopts planetary gear transmission (Figure 5), and mainly uses involute planetary gear differentials, of which 2K-H Most applied.
The planetary gear train is composed of a sun gear, a planet gear and a planet carrier. In the planetary gear transmission shown in FIG. 5, gears 1 and 2 are sun gears, H is a planet carrier, and gears 3 and 4 are planet gears. On the one hand, the planetary wheel rotates (rotates) around its own geometric axis Q1Q2, and at the same time, it rotates (revolves) around the fixed geometric axis OO with the planet carrier H. If there is a central gear setting in this planetary gear, the degree of freedom is 1, it is a planetary gear train; if the central gears are not fixed, and its degree of freedom is 2, it is a differential gear train.
5. The main component of drilling fluid centrifuge-hydraulic coupling <br /> In order to effectively control the overload of drilling fluid centrifuge and make it start smoothly, run or meet the speed regulation requirements, therefore, the transmission system of drilling fluid centrifuge In the past, hydraulic couplings have been widely used.
Hydraulic coupling is a kind of night transmission, which uses hydraulic dynamic pressure to transmit power and torque. Figure 6 shows the basic mechanism of a fluid coupling. It consists of work wheels, housings, output shafts, bearings, seals and other parts. The case is filled with a working fluid (mineral oil). The work wheel connected to the motor shaft turns the input mechanical energy into liquid kinetic energy, which is equivalent to a centrifugal pump work wheel, commonly known as a pump wheel. It reduces the kinetic energy of the working fluid to mechanical energy and drives the load through the output shaft. The casing is connected to the pump wheel to form a container for the working fluid. The speed of the turbine is lower than that of the pump wheel, the relative slip ratio is 3% to 4%, and the efficiency is 96% to 98%.
However, with the increase of the rotating speed of the rotating drum, the hydraulic coupling can no longer meet the startup requirements of high-speed drilling fluid centrifuges. Therefore, the development trend of high-speed centrifuges is to use inverter control to truly achieve soft start, that is, frequency conversion drilling fluid centrifuge . The variable frequency drilling fluid centrifuge has the performance characteristics of small impact on the power grid and high degree of intelligence. The large-flow variable-frequency drilling fluid centrifuge can adjust different speeds according to demand, thereby generating different separation factors, so that the drilling fluid centrifuge can recover or remove the solid phase according to process requirements.