It is for this reason that a considerable amount of conveying data for different materials is included in this Design Guide and that a lot of consideration is given to this topic throughout the book.
Availability of design data
Pneumatic conveying system design may be based upon previous experience or upon test results. Unfortunately commercial interests dictate that manufacturers of pneumatic con- veyors rarely publish information that could be of value in system design. A single value of material flow rate, conveying distance, and possibly pipeline bore and air supply pres- sure, is normally the extent of the information given. Even user companies, many of whom have had to ‘tune’ their own systems are generally reluctant to divulge detailed information on the performance of their conveying systems, for commercial reasons.
Different materials are quite likely to have totally different conveying properties and if a system has to be designed for a material for which no previous experience is available, it will be necessary to carry out pneumatic conveying trials. These will gen- erate the data upon which the design can be based.
In this Guide, conveying characteristics for a number of materials are presented which detail the relationship between the main conveying parameters for a material, over a wide range of conveying conditions, and the limits of conveying are clearly iden- tified. With data presented in this form system design is relatively straightforward.
This type of data also allows analysis of existing systems to be carried out. Checks can be made to determine whether a system is operating under optimum conditions and, if not, how this can best be achieved. Similar checks will enable an assessment to be made of the potential for up-rating a system.
Scope of the work
The Guide is intended to be used by both designers and users of pneumatic conveying systems. For those not familiar with pneumatic conveying it provides information on the types of system available and the capabilities of pneumatic conveying systems in terms of material flow rates, conveying distances and power requirements. This should enable a project engineer both to assess alternative tenders received for a pneumatic conveying system and to make comparisons with mechanical systems.
For the designer, data on a number of materials is presented which could be used for the design of systems to handle these materials. Where system design is based on results obtained from a test facility the actual plant pipeline will have a totally differ- ent configuration. To overcome this problem scaling parameters are presented for con- veying distance, pipeline bore, vertical sections and pipeline bends to enable the test data to be used reliably. For any given conveying duty a range of air supply pressures and pipeline bores will be capable of meeting the required duty. The design procedures outlined will allow selection of the combination that will give the lowest power requirement.
For users of systems the Guide will explain how to check whether an existing system is operating under optimum conditions. The possibilities of up-rating systems, extend- ing systems, and changing to a different material are also considered. Operational problems are featured with separate chapters devoted to an analysis of problems such as erosive wear, particle degradation, explosions, and moisture and condensation. The commissioning of systems and troubleshooting are also considered so that the cause of plant operating problems, such as pipeline blockage, can be determined and corrected.