Screw conveyor - assembly drawing

Contents

PAPER

The course design contains 45 pages of text material, assembly drawing and detail of the designed screw conveyor

INTRODUCTION

1. ANALYSIS OF MODERN SCREW CONVEYORS

1.1. Stationary and mobile conveyors

1.2. Horizontal and inclined conveyors

1.3. Vertical Conveyors

1.4. Conveying pipes

1.5. Forced and Free Loading Conveyors

1.6. Technical specifications of screw conveyors

2. DESCRIPTION OF SCREW CONVEYORS

2.1. Purpose and Scope

2.2. Description of design and principle of action

2.3. Technical characteristics

3. CALCULATIONS

3.1. Screw diameter

3.2. Screw Pitch

3.3. Actual Pipeline Performance

3.4. Power required for drive

3.5. Required Motor Power

3.6. Torque on screw shaft

3.7. Diameter of output end of trunnion

3.8. Screw shaft diameter

3.9. Bearing seat diameter

3.10. Forces acting on the screw

3.11. Angle of helical line lifting

4. INSTALLATION, OPERATION, REPAIR OF SCREW CONVEYORS

CONCLUSION

LIST OF LITERATURE USED

Introduction

Several millennia BC, in ancient China, India, chain pumps were used to continuously supply water from reservoirs to irrigation systems, which can be considered prototypes of scraper conveyors; in Mesopotamia and ancient Egypt, multi-oar and screw water lifts were used - the predecessors of modern bucket elevators and screw conveyors. The first attempts to use scraper and screw conveyors to move bulk materials (for example, in the flour mill) belong to XVIXVII centuries. At the end of XVIII in. conveyors began to be systematically used to transport light bulk materials over short distances. In the 30th century XIX in. for the same purpose, conveyors with strands of strong fabric were first used. In the 2nd half of the XIX century. the industrial use of conveyors for the delivery of heavy bulk and piece cargoes began.

Since the 80s XIX in. the manufacture of conveyors in industrialized countries gradually separated into a separate field of mechanical engineering. In modern types of conveyors, the main structural elements have been preserved, which were improved in accordance with the achievements of science and technology (replacing the belt drive with electric, using vibration technology, using compressed air energy ).

An auger or screw conveyor is a device that moves a load along a trough by means of a rotating shaft equipped with blades located along a screw line. The simplicity of construction, high productivity, reliability and unpretentiousness of screw conveyors make them widely used in various areas of production activities related to the movement of large volumes of bulk cargoes.

As the screw rotates, the blades push the weight along the chute. Screw conveyors consist of sections 2-4 m long, the total length of which does not usually exceed 60 m, the diameter of the trough is 100600 mm. Screw conveyors are simple in design, easy to use, especially when transporting dust loads. However, the blades and the chute wear relatively quickly, the load is ground and abraded, in addition, increased energy consumption is required..

Nowadays, screws are very often used simultaneously both for moving the load and for performing technological operations, for example, mixing, drying, cooling. Therefore, the design of screws, their calculation and study are very important, especially in relation to food engineering.

Purpose and Scope

Screw conveyors are used for transportation over short distances (3040 m) of loose and fine pieces (cement, gravel, sand, slag, etc.), as well as viscous and dough-like (wet clay, concrete, dough, mince, etc.) materials. It is not advisable to transport sticky and strongly compacted, as well as highly abrasive weights with screw conveyors.

Screw conveyors are quite widespread due to the fact that they have a closed transport path and are suitable for the movement of dust, toxic and hot materials. Screws are used mainly in the food industry, the construction materials industry (for transporting cement), in the chemical industry (for transporting dust and toxic products), in power plants (for transporting coal dust). Screw conveyors are used on elevators and in granaries, in feed mills, farms as a dosing device and in many branches of the food industry.

Screw conveyors that transport materials horizontally or at a small angle to the horizon have become most widespread. Sometimes special vertical screw conveyors are used that carry out the vertical transportation of materials. These conveyors have little distribution and are not mass-produced.

A special case of using vertical screw conveyors (with a very small screw diameter and low productivity) is the use of them as installations for drilling vertical wells and holes.

Conclusion

In the course of work on the course project, various mechanisms, devices and installations of screw conveyors were considered and analyzed. With regard to the food industry, screw conveyors (screws) are very widely used in the meat and bakery industries, and are an integral part of technological equipment. The design and calculation of screws is a fundamental part of the lifting and transportation plants of the food industry.

This course design shows the positive and negative aspects of using different types of screw conveyors.

The advantages of the screws include simplicity of the device and ease of maintenance, small overall dimensions, convenience of intermediate unloading, tightness, which is especially important when moving dust, hot and sharp loads.

Disadvantages of screw conveyors are the high specific energy consumption associated with the transfer method, significant attrition and grinding of the load, increased wear of the screw and trough, as well as sensitivity to overloads, leading to the formation of a cluster of weights inside the trough (especially at intermediate bearings).

Currently, equipment including screws is popular and popular, so the calculation and design of various screw conveyors with new specified parameters plays a large role. An example of such a design calculation is presented in this work.