Mud recycling plant uses screens to direct, separate, and control drilling fluid flow in the process. The heart of Mud recycling system is the shale shaker. This vital piece of equipment filters out the gritty pieces of the Barnett Shale from the drilling fluid (or “mud”), so that the fluid can recirculate and thus continue the recycling process. The two main purposes for screening the mud recycling plant are to remove oversize material from the shaker or undersize solids from the mud recycling plant and completely size the solids produced. a mud recycling plant must perform both functions.
The feed may contain mud solids that does not have to be crushed and which should be removed from the input to the primary crusher. A scalping shaker is frequently used between the feeder and the primary crusher to remove from the feed material that is smaller than the setting of the crusher. It may be a grid, grate, or screen, and it may be stationary or it may vibrate. Solids removed from the feed is directed to finish screens and reduction crusher.
The grizzly is the most commonly used scalping shaker. It consists of evenly spaced. Parallel, tapered, and inclined bars running in the direction of the feed to the crusher. Undersize material (solids) in the feed drops through the bars and oversize material is stored on the bars and discharged at the end of the grizzly. Therefore, the spacing of the bars is determined by the desired size of feed.
Design Features Of Screens
Screens are made of perforated steel plates or wave wires which form a mesh of square or rectangular openings between adjacent screen material. The three basic types of screens used for mud recycling processing are known as:
- inclined vibrating screen.
- horizontal screens.
- revolving screen.
Mud recycling plant normally uses horizontal screen to remove and recycle materials. The horizontal screen is a modern vision of the shaker screen for improved effectiveness caused by higher speed motion and a shorter stroke. It is similar to the inclined vibrating screen but it requires less headroom. Since it is held in a horizontal position, this screen is not used for scalping.
Protect the Investment
Operators must think about how to protect their investment beyond purchasing durable screens. Proper maintenance will affect all screens’ quality. On the job site, screens should be kept in their boxes and stacked flat (or in accordance with the manufacturer’s recommendations). Mishandling panels, especially during storage and installation, may cause premature screen failure. Operators should also ensure that screens are always properly mounted, check for proper tensioning and replace worn deck and crown (channel) rubbers as soon as possible. Personnel should never walk on screens when working on shakers. They should also avoid dropping tools on screens. After service each day, screens should be washed down, especially if drilling is occurring in sticky solids such as clay. Periodically, screens should be carefully inspected for tears and holes. If unresolved, these issues will lead to a major mud weight problem and may cause a heavy buildup of solids being returned to the active mud tank. Monitoring for extremely high mud weights will also help extend screen life. All personnel must be cognizant of the proper operation, installation, storage and maintenance of shaker screens.