Mactenn Systems - Specialist Valves and Advanced Materials Handling

Mactenn Systems Ltd. is a member company of the Macawber Engineering USA group of companies. The group is a world leader in the design and manufacture of special low-velocity dense-phase pneumatic conveying systems and inflatable seat valves for chemicals, minerals, plastics, food, pharmaceutical and other process industries.

LOW-VELOCITY DENSE-PHASE PNEUMATIC CONVEYING

Mactenn has introduced the advantages of very low-velocity pneumatic conveying to many plants throughout Europe. The advantages of the unique conveying process are the ability to avoid particle degradation during the conveying process. The low velocity conveying process provides major savings in power cost with exceptional mass ratios. This has been widely used for polymer handling requirements to avoid dust generation and particle extrusion into unwanted strings of material.

The system design approach is to carefully examine the material characteristics and the system design objectives before selecting a suitable pneumatic conveying regime and desired efficiency level. The company has a range of system types available for almost all system requirements, from short to long distance conveying, up to 1,500m.

CONTROLLED INJECTION RATE OF MATERIALS INTO PRESSURISED PROCESSES

The continuous development of material injection processes has achieved notable unique installations where the chemical process requires a continuous feed of materials controlled to high levels of injection rate. This is achieved with the Dosamatic injection process, where a materials feeding device operates within a pressure vessel.

This process allows a pressure potential for materials rate injection control and reliable performance against the chemical process pressure. Flow accuracies of up to ±1% of flow rate, independent of backpressure variations, are available. Also a flow rate turn-down of better than 20:1 without loss of flow accuracy is available.

The process considerably improves on-line control of pressure or vacuum processes where dynamic balance of the reaction is required. It is also possible to link the process parameters with the injection rate control to eliminate certain variations.

INFLATABLE SEAT VALVES FOR RELIABLE PROCESS CONTROL

The group pioneered the Dome Valve (Inflatek valve in Europe), inflatable seat valve more than 20 years ago. Continuous development has achieved advances in operating reliability and valve life. The valve has been widely applied throughout industry where there is a need for leak proof closure when handling abrasive bulk materials where there is a pressure differential across the valve. The level so far is for applications to 43Barg and temperatures to 380°C and sizes to 600mm. In 2000 the group re launched the Dome Valve, now designated Dome Valve II, to introduce advanced features. The developments have made the valve maintenance free, even in the most arduous applications.

The closing and sealing process allows the closing member to cut through a static column of abrasive material and in the same action achieve a pressure tight seal across a very high-pressure differential. The seal member is able to compensate for gradual wear and therefore achieve extremely long valve lifetime.

There are more than 30,000 valves in service throughout the world. The valve is available from the group factories in the UK, USA, India and China.

PRESSURE OR VACUUM LET-DOWN SYSTEMS

The inflatable Dome (Inflatek) Valve has been heavily used for continuous pressure let-down applications where it is necessary to introduce a processed material into atmosphere from a continuous pressure or vacuum process. Two valves are used between a pressure or vacuum lock vessel together with a control facility that allows correct pressure or vacuum relief. This arrangement has been used with high volume requirements such as Teraphalic acid powder at high temperature and moisture content, with rates up to 50t/h.

The group has grown steadily since 1977 and now has four strategically located factories and more than 25 associated companies worldwide. Factory support is available from the USA, UK, India, China and Brazil. The considerable knowledge and experience of the specialised field of material handling, together with knowledge of associated processes has been a primary contribution to the success of the group.