Cement Bulk Trailer Working Principle

Cement bulk trailer (hereinafter referred to as “cement trailer” or “powder tank semi-trailer” in this section) is generally discharged by compressed gas pneumatic discharge.

1. Fluidization principle

When a certain pressure and velocity of the gas is introduced into the stack of powder material, the stack of powder material will have some liquid-like characteristics and can flow to the lower and low-pressure areas, which is called fluidization of powder material.

This phenomenon is called fluidization of powdery materials, as shown in Fig. Figure (a) shows that the large and light materials in the powdered material are bouncy and will float upwards when the powdered material is blown by the compressed gas. Figure (b) shows that the powder material is fluid when it is blown by compressed gas at a certain pressure and speed, and the upper edge of the support body remains horizontal when it is tilted. (d) shows that after the powder material is fluidized, when a small hole appears on the side of the support body, it can be ejected from the small hole on the side of support body.

cement trailer makes use of this characteristic of powder material to realize pneumatic transportation.

 

2. Types of cement trailer

2.1 Classification according to the form of cylinder structure

cement trailer according to the cylinder structure type, not a cylinder, can be divided into the following categories.

1)Horizontal cement trailer

The horizontal cement trailer cylinder axis is horizontally arranged, or with the horizontal direction into a small angle of inclination. The structure of a horizontal cement trailer is relatively simple, easy to operate, low center of gravity and is relatively lightweight, but the scope of application receives certain restrictions, generally used for the transport of powdered solid materials with good fluidization performance. As shown in the figure, it is a powder tank semi-trailer.

2)Vertical cement trailer

The vertical cement trailer’s cylinder body is vertical in the middle axis, and the vehicle can be composed of a single or several vertical cylinders. A vertical cement trailer can transport a wide range of materials, and the residual rate is very low, but the manufacturing process is complicated, the center of gravity of the vehicle is high, and the volume is small under the same length.

3)Lifting type cement trailer

In the process of operation and loading, the central axis of the cylinder is generally in the horizontal direction. When the unloading operation is carried out, the front part of the cylinder is lifted up by the lifting device, and the cylinder as a whole becomes a certain angle with the horizontal surface, and the angle is greater than the static resting angle of the loaded medium, as shown in Figure 2-4. Lifting cement trailer only in the tank at the end of the discharge port laid fluidization device, discharging state powder material under the action of gravity to slide to the discharge port. Lifting type cement trailer has a simple structure and a wide range of media, but it is costly because of the additional lifting device, and the center of gravity is higher when discharging, which requires high requirements for the use of the site.

4)Bucket type cement trailer

The tank part of bucket type cement trailer consists of a straight cylinder arranged horizontally and a conical bucket arranged vertically, as shown in the figure. Its structural characteristics are between a horizontal cement trailer and a vertical cement trailer.

 

3. Density division

Divided according to the density of shipped powdered solid materials

According to the density of the shipped powdery solid materials, it can be divided into the following three types.

• (1) low densitycement trailer: special tank-type transport vehicle for transporting powdered solid materials with loose density less than or equal to 700kg/m3.
• (2) medium density cement trailer: used to transport the loose density between 700kg/m3 to 1200kg/m3 of powdered solid materials tank-type special transport vehicles.
• (3) High-density cement trailer: A tank-type special transport vehicle for transporting powdered solid materials with a loose density of more than 1200kg/m3.

 

4. Cement tanker’s unloading capacity

At a distance of 5m in the horizontal direction, a height of 15m in the plumb direction, and a discharge pressure of 0.2MPa, the average discharge speed of the cement trailer should be greater than or equal to 1.2t/min, and the residual rate of powder material should not be greater than 0.3%.