separation

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Oilfield screen shaker separator normally called oilfield shale shaker or screen separator. It is the first step solids control equipment used in oil field and other drilling activities. It is the necessary solids control equipment for mud systems, no matter for oil and gas drilling, HDD, CBM, TBM, or piling.

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Per the motion type of screen shaker separator, there are linear motion screen shaker separator and balance elliptical motion screen shaker separator.  
Oilfield screen shaker separator is normally linear motion type. And linear motion screen shaker separator is the most popular and long history type. Linear motion is more reliable. It can suits more kinds of jobsite condition.
While Balance elliptical screen shaker separator is very limited with jobsite and mud condition. When there are big load of mud, or the mud fall onto screen shaker deck unequally, the motion will be damaged and the BEM shaker cannot be working well. Mud will be over flow.

Per shaker deck quantity, there are single deck screen shaker separator and double deck screen shaker separator. Double deck screen shaker separator can be used for scalping shaker separator. The top deck use coarse mesh screen for pre-separation, while the bottom deck use normal mesh wire screen per jobsite condition.

Per the difference of applications and G force, screen shaker separator can be divided into solids control screen shaker separator and drilling waste management high G screen shaker separator. Beside the application G force is different, for solids control screen shaker separator and drilling waste high G force screen shaker separator, the feeding type of the 2 screen shaker separator is also different.
Solids control screen shaker separator is normally use top type or back type weir feeder, or box feeder, while drilling waste screen shaker separator is use hopper feeding.
Solids Control screen shaker separator can be fed by slurry pump or fed directly from the rig manifold under gravity. While drilling waste screen shaker separator can be fed by screw conveyer or cuttings transfer pump.  

Functions of decanter centrifuge speed for VFD and PLC system

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Decanter centrifuge is widely used for drilling rig mud system; it can be used from barite recovery, fine solids separation, as well as for waste management. It is utilizing different speed to vary G force and to separate different size solid particles from drilling fluids. In this case, centrifuge G force is very important for the performance.  

How to change decanter centrifuge speed for VFD and PLC system

It is actually differential speed what decides G force. Differential speed have relationship with bowl speed, gearbox input speed and the gearbox ration. Gearbox ration is usually a fixed figure for a certain decanter centrifuge model. Below is the relationship of them:

Differential Speed = ( Bowl speed – Gearbox input speed) / Gear Box Ration

 Take GNLW363VFD decanter centrifuge as an example, Gear Box Ration=57. Blow speed and gearbox input speed (conveyor speed) is changeable; they can be set on the PLC touch screen of the VFD centrifuge.  

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So Gearbox input speed=Bowl Speed – 57×Differential Speed= Small Motor Speed transferred to gearbox by belt, in some occasions, it is also called conveyor speed.

 Below we see 2 examples

Case 1) Bowl speed=3200RPM, and Differential Speed=30RPM

Gearbox Input speed=3200-57×30=1490RPM ,

Case 2) Bowl speed=1200 RPM, differential speed=35 RPM

Gearbox Input Speed= 1200-57×35= -795RPM it is a negative number.

Above situation, you can see, sometimes the gear box speed is  a positive number, that means small motor running according to the Arrow on the belt cover. Watching from feeding tube side the small motor rotation is Anticlockwise.

The motor speed is changed for some condition. GN brand VFD centrifuge have program to control the motor speed and motor direction. It can changed automatically when necessary.

 

 

Conveyor, also called screw propeller. It is the most important part of waste management decanter centrifuge. We can also see it as the core of decanter centrifuge.

For different conveyor speed, the separation performance is different. For different drilling fluids, the centrifuge conveyor should defer. Professional users know how to change for a suitable speed for a better performance.

GN variable speed centrifuge (VFD), conveyor speed can be changed during centrifuge running. Customer can change the conveyor speed per different drilling fluids type.

For GN decater centrifuge, main motor is connected directly with bowl. Back motor is connected with gearbox and then connect with centrifuge screw propeller. When change the frequency of the motor, customer can get the different conveyor speed.

GN Solids Control manufactures customized dewatering units.

GN design dewatering unit is complete containerized unit with various pump and decanter centrifuges.

20’ Containerized Dewatering Unit is a smaller size dewatering unit, GN have big size 40ft for option.

GN provide optimum performance when combined with GN proprietary dewatering centrifuge. with PLC control. It is easy for operation and reliable for running.

GN 20’ mobile dewatering unit can be transported as a standard container for overseas and land shipping. The system includes all the standard dewatering components with the centrifuge mounted on a separate telescoping skid or on your own mud tank.