Operation

Development is driven by the constantly growing possibilities of theoretical simulations of those physical processes in compressor installations, which reduce their reliability, lifetime, and efficiency. Thereby methods are being developed to improve the design and the condition 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 they are typical examples.

Compressor valves are being developed, which combine the efficient flow characteristics of ring 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 [22].

Electromagnetically influencing the 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 [23].

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 3D flow structure model, so that expensive revisions after trial runs can be avoided [24].

In order to increase the lifetime of packing rings a theoretically based design method is being used, enabling reduced contact pressures and minimal leakage gaps [25].

Through the development of suitable sensors systematic monitoring of guide ring wear [5] and oscillations of the piston rod [26] can be achieved.

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

Thereby methods are being used, which work not only in the frequency area but also in the time area [28]. The 1D calculation, which is normally used, is then supplemented by a 3D model, which takes into account the shape of components that deviate strongly from the pipe shape [29], [30]. In addition, 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, [31]. Usually, the calculations are complemented by measurements on the final installation, leading to further dampening measures [32].