FI125540B - Procedure for improving the pressing and quality of pellets - Google Patents

Description

The present invention relates to a process according to claim 1 for enhancing the process of pelleting loose materials such as woodworking waste, etc., and for improving the density, strength and quality of the compression.

Known piston-based pelletizing or briquetting machines provide the counter-force required to produce a compression, with the length and diameter of the compression channel being correct with respect to the material to be extruded. Often, separate replaceable nozzle elements are also used to change the cross-sectional area of the channel and to adjust the clamping force. Other means of improving the strength and quality of the press include at least the use of external heat, such as electric steam or additives mixed with woodworking waste, such as starch, molasses or plastic mill. The lignin, which is central to the formation of the molding, melts at about 80 ° C, which requires a pressure of about 120 N / mm 2 in the pressing channel.

The desired bulk density of the pellet or briquette is about 1-1.2 g / cm3. The compression underneath it is not strong enough to withstand the stresses of transport and other handling steps, while the compression above easily easily overloads the machine, causing malfunctions. The production of good quality, sufficiently dense and durable pellets or briquettes depends on the characteristics of the technology used, the control it provides, the raw material to be squeezed, and the humidity and temperature.

The object of the present invention is to provide a process which is capable of improving the density, strength, uniformity and general quality of pellets or briquettes produced from bulk material such as woodworking waste, etc. additional heat or substance. The invention is generally suitable for use in piston operations more preferably pat. hak. Machines according to FI20040412.

The method and apparatus of the invention are characterized by exactly what is claimed.

According to the invention, this object can be achieved by providing a reciprocating adjustment movement of the entire compression duct assembly in the direction of movement of the wood pulp pelletizing piston.

According to the invention, this purpose can be achieved by supplying compressed air to the compression chamber at the beginning of the compression movement of the pelletizing piston, whereby the volume temperature decreases and the pressure increases (Boyle's Law).

The invention will now be described in more detail with reference to the accompanying drawings, which show, in partial sectional views, one device according to the invention and method.

Figure 1 shows a known device.

Figure 2 shows a top view of a known device.

Figure 3 is a cross-sectional view of a known device.

Fig. 4 is an enlarged view of a compression duct assembly.

Figure 5, shows an enlarged view of the air channel.

Figure 6 shows a nozzle element.

Figure 7 is a side view of the nozzle element.

Figure 8 shows a top view of a nozzle element.

Figure 9 shows a cross-section of the nozzle element.

Figure 1 shows the pat. A pelleting machine according to hak FI20040412 wherein a hydraulic pre-press member 1 pushes material to be pelleted by means of a pre-compression piston 16 into a pre-compression passage 3 and further into a pre-compression chamber 15 against a piston 17 and a pre-compression chamber 15. The desired pre-compression pressure is measured electronically from the hydraulic medium and transmitted to a control unit which locks the pre-compression member and transmits the pelletizing piston 11 pushed by the hydraulic pelletizing member 5 to push the pelletable material into the compression passage 8 and further through the nozzle element 10.

The pelletizing piston 11 cuts an opening corresponding to its diameter in its pre-compression mass during its movement. The length is formed by the distance between the rear end of the pelletizing piston 11 and the opening of the compression channel 8. The density and length of the pellet blank cut by this pelletizing piston 11 into the pre-press depends on the length and weight of the resulting pellet.

In accordance with the inventive idea, the length of the pellet blank can be influenced by providing a reciprocating adjustment movement of the entire compression duct assembly 6, (including parts 8, 9, 10, 12, 13 and 14) in the direction of compression movement. The distance between the opening of the compression channel 8 and the pelletizing piston 11 in its rear position can then be varied according to the need for adjustment within the range of movement 9 of the adjustment. Advantageously, this adjustment method can be used to obtain a suitable length of pellet or briquette for various pelletizing materials which affects the back pressure generated in the press passage 8 on the density, strength and uniformity of the press and prevents the press from jamming into the press passage 8 or nozzle element 10.

In accordance with the inventive idea, pellet strength, quality uniformity, and pellet mobility can be influenced by timed supply of compressed air 20 through block 4 air passage 18 and compression passage air passage 19 to compression passage 8 and pre-compression chamber 15. rise (Boyle's Law). The compressed warm air, in turn, heats the compressed pulp, thus promoting the lignin melting and pelletizing process. This method affects the strength of the pellet as well as its release from the previous pellet as it discharges from the cooling passage 14.

Reference Numbers 1. Pre-press member (Figure 1).

2. Feed hopper (Figure 1).

3. Pre-compression channel (Figure 1).

4. Block (Figure 1).

5. Hydraulic pelletizing element (Figures 1 and 2).

6. Compression duct assembly (Figures 1,2,4).

7. Compensator (Fig. 1).

8. Compression channel (Figure 4).

9. Adjustment travel limit (Figure 4).

10. Replaceable nozzle element (Figure 4).

11. Pelletizing piston (Figure 4).

12. Component of compression duct assembly (Figure 4).

13. Compression Duct Assembly Nut (Figure 4).

14. Cooling duct (Figure 4).

15. Pre-compression chamber (Figure 4).

16. Pre-compression piston (Figure 4).

17. Piston of pre-compression compensation member (Figure 4).

18. Block air channel (Figures 4, 5).

19. Compression duct air channel (Figures 4, 5).

20. Compressed air (Figure 5).

The invention can be applied not only within the skill of the art but above all within the scope of the claims.

Claims (2)

1. A method for improving pellet or briquette density, strength, length, pelletizing pressure and temperature control, as well as quality uniformity, in piston-driven, two-stage separate pre- and pellet-pressing cross-compression machines with pre-extrusion (pre-compression) (15), to a variable volume between opposing directions of movement of the pressing members (7,16), characterized in that the length of the pre-press cut by the pelletizing piston (11) and the final pellet can be varied by adjusting the distance of the pressing channel in the compression direction with respect to the pelletizing piston (11). A method for improving pelletizing pressure and temperature control in a compression passage (8) according to claim 1, characterized in that the compression passage (8) and the pre-compression chamber (15) are controlled by compressed air (20) which compresses when heated to increase the temperature of the resulting compression. the molding.