What’s the differences between desanders, desilters and vibrating screen?

• Desander

The desander is a secondary solid control equipment in the drilling fluid solid control equipment system. Its main function is to remove solid particles larger than 47 microns in the drilling fluid, in order to protect subsequent solid control equipment, especially the mud remover, from being damaged by large particles. The working principle of the sand remover is to use centrifugal force and gravity to settle and discharge sand particles in the drilling fluid, in order to achieve the purpose of purifying the drilling fluid.

Desander usually includes parts such as inlet pipe, cyclone, underflow port, and sand discharge port. The drilling fluid enters the cyclone through the inlet pipe and generates high-speed rotation inside the cyclone, causing solid particles to move outward under centrifugal force, while gravity also causes particles to settle downwards. These particles are ultimately discharged through the bottom flow port and sand discharge port, while clean drilling fluid flows out from the upper part of the cyclone and enters the subsequent processing flow.

Desander plays an important role in the drilling process. It can effectively reduce the content of solid particles in the drilling fluid, reduce the wear of drilling tools, improve drilling efficiency, and also help protect the environment and reduce the pollution of drilling fluid to the environment. Therefore, the selection and use of sand removers are very important in drilling operations.

• Desilter

The desilter is a three-stage solid control equipment used in the drilling fluid solid control system, mainly composed of a vibrating screen, a diversion manifold, a cyclone, and so on. It is designed based on the principle of particle settling and generates a certain pressure and velocity through a sand pump, allowing drilling fluid to spiral into the inner wall of the cyclone. In the cyclone, coarser particles spiral down the inner wall of the cyclone under the action of centrifugal force and gravity, are discharged from the bottom flow port, and fall on the fine vibrating screen below for separation. The remaining medium rises along the spiral of the cyclone.

The desilter has high separation capacity and a wide range of separation particle sizes, and is commonly used to treat wastewater or sewage containing a large number of small particles, such as urban sewage treatment plants, industrial wastewater treatment, etc. Its cyclone has a pressure umbrella shaped "wet bottom" sand discharge at the bottom flow port, allowing particles in the separation zone to be quickly discharged and reducing the probability of blockage at the bottom flow port. In addition, the desilter also has a symmetrical liquid inlet mechanism, which makes the swirl distribution reasonable and the operation stable.

In drilling operations, the desilter is usually installed after the sand remover to further remove solid particles from the drilling fluid and improve its cleanliness. Its installation, debugging, maintenance, and upkeep all need to be carried out according to specific specifications to ensure its normal operation and extend its service life.

• Vibrating screen

A vibrating screen is a screening equipment that operates by utilizing the reciprocating rotary vibration generated by the vibration of the oscillator. It mainly consists of a sieve and a shaker, with the thickness of the sieve expressed in mesh. Generally, a coarse sieve is used for screens below 50 mesh, and a fine sieve is used for screens above 80 mesh. The oscillator is an eccentric wheel that rotates under the drive of an electric motor, causing the screen frame to vibrate. When the material flows onto the sieve surface, coarser solid particles will remain on the sieve surface and be discharged from one end along the inclined plane, while finer solid particles and liquids will flow out through the sieve holes.

The vibration trajectory of a vibrating screen is a complex spatial curve, with a circular projection on the horizontal plane and an elliptical projection on the vertical plane. By adjusting the excitation force of the rotating heavy hammer up and down, the amplitude can be changed; By adjusting the spatial phase angle of the upper and lower weights, the curve shape of the screen surface motion trajectory can be changed and the material motion trajectory on the screen surface can be altered.

There are various types of vibrating screens, such as linear vibrating screens, circular vibrating screens, high-frequency vibrating screens, etc. They have wide applications in different fields, such as mining, construction, chemical, pharmaceutical, food processing, etc. In these fields, vibrating screens are used to screen various materials, ensuring the quality and purity of the materials.

What’s the difference between them?

Desander:

The sand remover is mainly used to remove solid particles with a particle size greater than 47 microns from drilling fluid. Its working principle is based on the effects of swirling flow and centrifugal force. When drilling fluid passes through the cyclone of the sand remover, rotational motion occurs, causing solid particles to deposit towards the wall of the cyclone under the action of centrifugal force, while cleaner liquid flows inward and is discharged from the outlet. Desander is usually used as a secondary solid control equipment in the solid control system to reduce the load of downstream desilters.

Desilter:

The mud remover is used to further remove solid particles with particle size less than 25 microns from drilling fluid. Similar to a desander, a desilter also utilizes the effects of swirling flow and centrifugal force to achieve solid-liquid separation. However, compared to the sand remover, the mud remover needs to handle finer solid particles, thus requiring higher accuracy and more complex separation techniques. The mud remover is an important three-level solid control equipment in the solid control system, used to improve the cleanliness of drilling fluid.

Vibration screen:

A vibrating screen is a device that works by utilizing the reciprocating rotational vibration generated by oscillator excitation. It is mainly used for solid-phase treatment of mud, which separates solid particles from drilling fluid through the vibration of the sieve. There are various types of vibrating screens, and different specifications and types of screens can be selected according to needs. The vibrating screen has the advantages of high efficiency, light weight, complete and diverse series, and is widely used in industries such as coal, petroleum, and chemical industry.

In the solid-phase control system of drilling fluid, the sand remover, mud remover, and vibrating screen are usually used in conjunction to achieve cleaning and solid-phase control of drilling fluid. Firstly, the drilling fluid removes larger solid particles through a sand remover; Then, fine solid particles are further removed through a sludge remover; Finally, the final solid-liquid separation is carried out through a vibrating screen. This combination can greatly improve the cleanliness of drilling fluid, reduce the impact of solid particles on the drilling process, and improve drilling efficiency and safety.

Unidrill desander combines the functions of desander and vibration screen, which take better performance in solid liquid separation of drilling fluid and realize the recycling of drilling fluid.