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• Material Testing The most proven approach to predicting conveying system performance is empirical, where materials are conveyed in industrial size pilot plants. With the best empirical approach, the conditions of conveying can be varied, to develop a set of data that can be reliably applied within tested and understood boundaries. The empirical method works well with both lean phase and dense phase conveying.Tests at various airflows and over various distances are usually carried out to build a set of data that describes the limits of successful conveying, in such a way that the information can be scaled for predicting the performance of the material over shorter or longer distances (up to 2000m), or with different sized pipes (25mm to 400mm).The results of these tests are stored in a material testing database. This forms the foundation of the know-how that is applied to prevent material conveying problems within gypsum plants, and allows Clyde to call upon tests of over 2000 different materials, over 100 in the gypsum industry, to assist customers. Indeed, it is highly recommended that when projects for DSG conveying arise, that only suppliers with proven experience and know-how relating to DSG transport be considered. In a few cases, Clyde have seen contracts carried out by suppliers who believe DSG is similar to other fine powder minerals, only to have severe problems for many years afterwards. • Line pressure control – Self Adaptive Technology DSG exhibits a tendency to fill the dense phase pneumatic conveying pipeline almost completely. This means that, without sufficient control, it is very easy for the conveying pressures to fluctuate, causing reductions in the material transport speed and consequently the conveying rate, often leading to blockages. To combat this property of some grades of DSG, Clyde developed a method of adjusting the pipeline-loading rate in order to maintain a pre-set conveying pressure condition, using proprietary Clyde ‘D’ Pump technology.The position of Clyde Materials Handling’s, Dome Valve, a renowned material handling valve used to control the flow of material within all of Clyde’s dense phase conveying solutions, helps to maintain the pre-set conveying pressure. When the Dome Valve was in the fully open position, the flow of material into the conveying pipeline was too great, and therefore caused the conveying pressure to increase. By closing the Dome Valve partially, material flow and conveying pressure stabilised and helped to transport both DSG and mineral gypsum in an efficient manner.The combination of internal by-pass pipe work, the Clyde Dome Valve and line loading control, resulted in a conveying system that can dense phase convey all grades of dried DSG and mineral gypsum, without any adjustments to the machine configuration or software.

Reference Stories

Clyde Materials Handling has worked with a leading producer of gypsum plasters and plasterboard over recent years.This producer was considering using DSG for the manufacture of its plasterboard produce. The organisation had prior experience of using this material, which proved to be difficult to transport effectively.As a result, they approached Clyde in an effort to establish if they had a conveying solution that was capable of handling DSG in a reliable and economically beneficial manner.Clyde set about conducting a serious of material tests to establish and understand the material properties of DSG, which consisted of material characterisation tests, real life conveying tests, flow characteristics of the material and self inflicted failure tests, designed to replicate actual existing site system conditions and performance of other equipment. The result of these tests provided Clyde with the information they required to design and develop a solution. This solution was the Self Adaptive Dense Phase Conveying solution , which has been described in detail in this brochure.Once developed, Clyde built a life size system in their R&D test facilities in Doncaster and carried out replica conveying trials of their client’s future requirements. The results of these trials were demonstrated and a presentation was presented to the client’s senior engineering management.This provided the leading producer with the confidence to place a single contract, direct with Clyde Materials Handling, to design and supply a system for one of their UK plants. The system was commissioned in November 2004 and to date, has achieved outstanding results in operation, offering the highest availability and reliability possible. The success of this DSG conveying system provided another of the leading gypsum producer’s plants with the confidence to select Clyde Materials Handling as the preferred supplier for a similar DSG handling solution for their proposed expansion of their plant.The success of this second system has allowed the leading producer to maintain the highest system reliability and availability levels that is required in a modern plaster production facility.Clyde Materials Handling has been able to provide the following powerful benefits to the gypsum industry: • Increase in system reliability • Reduction in air usage and energy costs • Reduction in operational and power consumption compared with existing systems • Significant increase in system availability levels • Simplistic and flexible conveying pipeline design • Totally enclosed, dust and spillage free system, generating exemplary environmental benefits • Fully automated, helping to reduce operating costs and provide even greater availability
Schematic Layout of Clyde’s Research, Development and Test Facility Clyde 'D' Pump Technology Clyde DSG Handling Solution Clyde’s Dome Valve Operation Illustrated Clyde Conveying Solutions Testing Materials

CMH Gypsum Brochure - 32078 98