1. Application

QJZ-300 type mud cleaner (Hereinafter called cleaner ) is a new solid control equipment which our company use high technology to design. It is used to remove 20~120μm drilled solids for saving mud and preparing for centrifuge to remove smaller the particle, thus you can effectively control the quality of mud to speed up drilling well, particularly in drilling deep oil well.

2. Technical data

 QJZ-300 type mud cleaner consists of shale shaker, desiliter, desander, its technical data to see table 1, table 2, table3.

Table 1  Shale Shaker Technical Data

Item	Data
Screen area     mm2	1050×700×3
Screen type     mesh	40~300
Amplitude      mm	>5.5
Adjusting angle	-3°~+6°
Type of flame-proof vibrating motor	YZB30-4
Ex-mark	dⅡBT4
Power         kw	1.5×2
Rated voltage   V	380
Frequency      Hz	45~60
Speed-RPM	1440

Table 2  Desilter Technical Data

Item	Data
Diameter of hydrocyclone   mm	Φ100
No. of hydrocyclones	16
Handling capacity         L/S	22~56
Remove size of the solid    μm	20~40
Range of pressure          Mpa	0.20~0.40

Table 3  Desander Technical Data

Item	Data
Diameter of hydrocyclone   mm	Φ250
No. of hydrocyclones	3
Handling capacity         L/S	35~55
Remove size of the solid    μm	68~120
Range of pressure          Mpa	0.1~0.3

3. Construction and principle

  QJZ-300 mud cleaner consists of shale shaker, desilter desander. The desilter and desander are above the shaker. They are united in the mud pan. There are two outlets of the mud pan, one is for shaker, another one is for discard in side of the mud pan. When you use a outlet, another one must be sealed.

  Desilter and desander are made up different hydrocyclones. Desilter is round construction. There are 16 hydrocyclones whose diameter is 100mm, they are averagely set around flow feeder. The round desilter is designed for maximum performance by providing exactly the same pressure (0.2~0.4 Mpa) to each cone. The hydrocyclones are made from lightweight, abrasive resistant polyurethane, for long life and easy maintenance. Shut-off valves (2″) on each cone inlet permit individual cone removal and inspection without interrupting operation of the desilter. They are also easier to operate and unplug if oversized solids plug the underflow. Simply unscrew the replacable wear section clean and replace. The inlet of mud is on the desilter top, its direction may be adjusted according to your requirement. There are two outlets of mud on side of the desilter. One is for use, another one must be sealed.

  The desander consists of inlet, outlet and hydrocyclones. The hydrocyclone is made up of top cover, top cone, bottom cone and nut. They are integrated by clamp bands. There is a discharge insert in bottom of the hydrocyclone. Weir pipe, inlet pipe and outlet pipe are also connected by clamp bands. You may adjust discard inlet through bottom cone nut according to the mud condition. When you use mew bottom cone, it is necessary for you to draw the bottom cone nut. There are two inlets of mud side of the desander, one is for use, another one must be sealed.

  The desilter and the desander may be operated in their range of the pressure. During operation, a feed slurry of solids and liquid is fed through the inlet at a high velocity obtained by steady pressure or feed head as recommended. A centrifugal pump is used to obtain the desired head. The high velocity into the feed chamber creates a spinning velocity and resulting centrifugal forces. The vortex finder causes the stream to spiral downward toward the underflow solids discharge. Centrifugal force and inertia cause the solids to settle outward toward the hydrocyclone wall, in the downward spiraling stream. As the cone section narrows, inner layers of the downward spinning liquid turn back toward the overflow because of the increasing centrifugal forces near the center. In this balanced design cyclone, as the last of the liquid moves to the center and back upward toward the overflow, the doward spiraling solids. Continne out the underflow, unable to turn back because of their greater inertia and high downward velocity. The discharge solids are discarded into the mud pan, then separated by shale shaker.

4. Installation and maintenance

4.1 The installation of the mud cleaner should be complied with relevant code and requirements. Lift the entire mud cleaner and place in position on the support structure. Four lift points at the lower corners of the machine are provided. The mud cleaner is lifted from the corner points, use spreaders to avoid distorting the unit.

4.2 The connecting of the desilter and desander should be used hard pipe and/or soft pipe. They are shorter as soon as possible.

4.3 The screen should be at the correct tension for use. It is excellent for uniform tension over the surface of the entire screen.

4.4 The vibrating motor and control box are both explosion-proof electric equipment, therefore, their installations should be in accordance with relevant National Electrical Code.

5. Operating

5.1 Before operating mud cleaner, you should inspect the unit thoroughly, such as mechnical system, electrical system, desilter, desander, connection of pipe.if there is any trouble or fault, you must repair and adjust.

5.2 The desilter and desander should be operated in range of their rated pressure. In the working of the mud cleaner, the stability of the pressure-metre, weir flow of discharge, sand should be often inspected.

5.3 In working of the shale shaker, you meed to be careful of the remove of the solids on the screen. When the screen blinding occurs, you should wash it down by spraying wate, don’t use spade to clean, otherwise the screen would be damaged.

5.4 When being changed screen, screen selection should be made on the basis of mud flow rate, type, weight and the anticipated behavior of the formation to be drilled. The screens are installed on the mud cleaner by the simple and effective method of engaging the hook strips of the screen panels into the drawbars provided and making up the rapid change bolt assemblies on the outside of the unit using spinner wrench, then, you fasten them well.

6. Maintenance

6.1 The wear-and-tear of hydrocyclones should be checked. If wearing capacity of any parts is 50% you should use mew parts. Particularly discharge insert, bottom cone nut. When the hydrocyclones are in condition not to be used. Open the feed header, rake out the material inside and wash it down.

6.2 Attention should be given to the condition of loosing of vibrating motor and screens. Once the problems occur, you should tighten the vibrating motor and screen properly, thus, the tension checked periodically may maximize screen life.

6.3 You should lubricatd and maintain vibrating motor on time. Adding oil (grease) in the oil orific of the vibrating motor a time once three months, the quantity is 30~40g per oil hole.

6.4 Easily and quickly raise or lower the screen basket from--3°to +6° by rotating spiral shaft.