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Trends

Trends

Trends

Development is driven by the continuing growing possibilities of theoretical simulations of  those physical processes in compressor intallations, which reduce their life expectancy and efficiency. Thereby methods are being developed to improve the design and monitoring of parts, machines and installations , which are of advantage to the user of such machines. In the following two problem areas are discussed as typical examples:

Compressor valves and sealing elements

Compressor valves are being developed, which combine the efficient flow characteristics of shaped ring type valves with the safe kinematics of plate type valves. The fact that these valve types achieve a long operating life even under difficult operating conditions is due to the optimised shape and material selection of both sealing element and springs. [23]

 Electromagnetically influencing valve motion over several working cycles in order to control  the volume flow can  be done in such a sophisticated way, that the influence on valve life and efficiency is reduced to a minimum. [24]

As the design of the cylinder has a substantial influence on the operation of the compressor valve, a design method of the cylinder has proven to be of advantage, which comprises the influence of geometry and flow via a 1D –model. Subsequently the layout is checked via a 3-D flow-structure model, so that expensive rectifications  after trial runs can be avoided. [25]

In order to increase the life of packing rings a theoretically based design method is being used, which renders possible reduced contact pressures and minimal leakage gaps.[26]

Through the development of suitable sensors  systematic monitoring of guide ring wear [5] and oscillations of the piston rod [27] can be achieved .

Pulsation- and low loss interstage systems

For medium and large size compressor stations a calculation according to API 618 is carried out in order  to forecast pressure pulsations and mechanical vibrations in the inter stages. The deviations from the calculations on the finished product can be diminished, if the method of calculation is improved.

Thereby methods are being used, which work not only in the frequency area but in the time area [29]. The 1D calculation which is normally used is then supplemented by a 3D model, which takes into account the shape of components which deviate strongly from the pipe shape [30,31]. Also, the modelling of pressure losses at non stationary flow is being continuously improved, so that predictions on the amplitude of pressure pulsations become more accurate. Thereby the strong increase of pressure losses close to resonance frequency can only be explained by energy dissipation in the pipe wall [32]. Nearly always the calculations are complemented by measurements on the completed  installation, which could lead to further dampening measures [33].