螺旋挤压脱水机(Screw extrusion dehydrator)是一种用于凝聚、脱水的主要设备。主要由螺杆、圆筒形笼式外壳和锥体三部分组成，由挠性联轴节将螺杆轴与减速器的输出轴连接起来。
Screw extruder is a main equipment used for coagulation and dehydration. It is mainly composed of screw, cylindrical cage shell and cone. The screw shaft is connected with the output shaft of reducer by flexible coupling.
Main Structure and Function of Each Component
The dehydrator is mainly composed of screw, cylindrical cage shell and cone. The screw shaft is connected with the output shaft of the reducer by flexible coupling.
The screw is composed of a screw thread and a shaft ring alternately sleeved on the screw shaft. Each thread and shaft ring are fixed on the screw shaft with keys. Except for the first section (feeding area) which is three-circle continuous threads with equal distance, the other sections are single-circle open type. The pitches of each section are different. The pitches of each section are gradually reduced from the low pressure side to the high pressure side, while the diameter of the hub is gradually increased to increase the pressure so as to extrude the moisture in rubber.
2. cylindrical energy shell
It is made of castor plates made of cage bars fixed on the skeleton. The castor plate is divided into 8 sections with different lengths. The inner diameter of the cylinder is 18 inches and is bolted in two halves along the vertical center line for easy removal during cleaning and maintenance. The cage bar consisting of castor plates is separated by springs to form longitudinal joints to cause water to flow out. A scraper is arranged on the skeleton of the upper and lower sides of the cylinder, which corresponds to the position of the axle ring on the screw. Its function is to prevent the rubber from rotating with the screw, force the rubber to change the direction and position of propulsion, and make it porous, so as to facilitate drying. There are four jackets outside the cylinder for heating or cooling, which can control the temperature in the machine according to the process requirements. In the production of styrene butadiene rubber, it is used only when steam is preheated before starting up the machine.
This is a conical cylinder located in the discharge area, which can be moved back and forth to match the ring fixed on the screw shaft. The front and back movement of the cone is driven by the gears composed of four jacks of the speed governing motor, and at the same time there is a manual adjusting mechanism. By moving the cone back and forth, the area of the sharp hole at the outlet is increased and reduced, so as to change the pressure in the machine, thus adjusting the dehydration rate of rubber. After extrusion of the rubber cone, the cutter is cut into small pieces on the screw shaft. Because rubber is heated by shearing force and compression inside the machine, water in the rubber flash evaporated when passing through the sharp hole of the cone, which makes the rubber porous.
1. Rotary filtration: sludge is flocculated by flocculant to form a certain strength flocculent. Solid-liquid mixture containing a large amount of free water enters the rotary filter through the overflow port of vertical reactor. Sludge moves forward under the impetus of the helical shaft blade. Because of gravity, it is dewatered freely, and the drum turns opposite to the helix. Sludge rolls continuously in the drum, and the free water in the floc is filtered out continuously. The concentrated sludge is pushed to the outlet through the spiral blade and enters the next dewatering process.
2. Screw extrusion: After the pre-dewatered sludge enters the screw extruder through the feed hopper, the sludge is compressed in volume under the action of taper helix axis and diameter-changing helix, so that the moisture in the sludge is quickly separated through the porous filter, while the moisture content of solid gradually decreases under the action of constant compression to become the filter cake we need, and finally discharge it out under the action of screw transportation.
For example, the dehydration of distiller's grains, fruit dregs, medicine dregs and cassava dregs can greatly reduce the burden of dryer, greatly increase the output and reduce the energy consumption. It is an indispensable treatment equipment before drying of high-humidity materials. The dehydrated materials can directly enter the drying equipment.