Actually the structural design of straw briquetting machine comes from pellet mill. In china, there are three kinds of straw briquetting machine—-mechanical press, Hydraulic press and screw press type.  

Mechanical press: it contains compression roller briquetting machine (belong to cold extrusion) and mechanical stamping briquetting machine( also have hydraulic press combined with stamping press which partial belong to hot extrusion) and so on. Diameter of briquetting is between 30mm to 80mm, and the density is between 0.8/m³ to 1.3/m³.   Mechanical stamping briquetting machines (or press briquetting machine, briquetting machine) adopts big press force with high speed and high frequency, press ratio is 300 per minutes. According to different density of straw, output is 0.8-1.2/ton every hour, and the finished products are 70mm or 80mm in diameter and the density is 1-1.25 g/cm3. Shape of straw stick is various, like round, quadrate and hexagonal. And that the finished products have holes in the center. Also we could produce according to clients’ requirements. 

Hydraulic briquetting press is comparatively simple, it is also called tying machine. Most of the materials are in the pattern of large bunch and has large size, the smallest is about 40cm*20cm*20cm, and the density is 0.4-0.7 mostly. Screw press briquetting machine (belong to hot extrusion) is mainly used to produce the charcoal bar with a hole in the center. Compressing roller die could be divided into ring die, flat die and ring&flat die( ring die with vertical shaft).

Ring die briquetting machine could be divided into: ring die briquetting machine with single roller and ring die briquetting machine with multiple rollers（ generally has two rollers and more than two individually）. Die of ring die briquetting machine is generally arranged the shape of “gong” modules into a round shape, most of the ring die hole is square shape, and also could be produced by customer’s requirements; the die could be integral with the round shape hole in the center mostly.

Flat die briquetting press machine are all vertical type, which has many holes on the round die ( also could be squared shaped). There are two or four compression rollers with this machine.  Ring & flat die ( vertical shaft briquetting machine) is actually means the direction of main shaft is perpendicular to the ground, that is vertical ring die briquetting machine, the other components are the same like ring die briquetting machine. Finished products of compression roller type is small in volume, and the transversal surface is usually about 30mm*30mm.