Sand and gravel production line: flow analysis of screening and washing equipment

The screening and washing of the sand and gravel production line is to divide the sand and gravel materials into several grades according to their particle size, and to wash the soil mixed in them. There are two types of screening operations: manual screening and mechanical screening.

(1) Manual screening device for sand and gravel production line

The three-layer screen is hung on the screen frame with a suspension rod and a catenary, and the inclination of the screen can be changed by changing the length of the catenary. The aggregate is loaded from the hopper with the screen bar on the top of the rack, the oversize stone is removed, and the rest of the aggregate falls on the screen. Repeatedly step on the pedal of the rocker mechanism with both feet, the screen will be shaken back and forth, and the aggregate will be screened.

(2) Sand production line screening machinery

The widely used screening machine is the plane vibrating screening machine. Which has the advantages of high productivity, high classification accuracy, low energy consumption, and small equipment size. The plane vibrating screen can be divided into eccentric vibrating screen and inertia vibrating screen according to the different ways of generating vibration. The screen frame of the eccentric vibrating screen is mounted on the eccentric main shaft. And the eccentric shaft drives the screen frame to make a circular motion to generate vibration. Its characteristics are that the amplitude is stable. It does not change due to the amount of aggregate on the screen, and it is not easy to block the screen holes; it is suitable for the screening of large and medium stones. It uses the inertia centrifugal force generated by the eccentric weight on the rotating main shaft to cause the screen to vibrate. When the amount of aggregate on the screen changes. Its amplitude will change with the deformation of the vibration damping spring. The disadvantage is that it is easy to block the screen when the feed is too much. It is suitable for the screening of medium and small stones.

Several rows of pressure water pipes with water jet holes are installed on the screen surface of the plane screen. Which can wash the aggregates at the same time of screening.

(3) Sand washing equipment for Sand production line. The commonly used sand washing equipment is a spiral sand washing machine.

In the sand washing chute, one or two long rotating shafts with spiral blades are installed. The machine body is placed at an inclination angle of 18° to 20°. Due to the rotation of the screw blades, the washed sand is stirred and moved to the high-end discharge port. The washing water is fed through a hose, and the sewage is discharged from the drain at the lower end. The spiral sand washing machine has a simple structure, reliable operation and wide application.