Suction header

Suction header below compressor level

As already recommended for single compressors (Suction gas line), the suction header should also preferably be fed to the compressors from below in the case of parallel compounding, so that the compressors are not flooded with oil when they are at a standstill.

For systems with potentially stronger liquid surges (e.g. hot gas defrosting, systems with long standstill under pressure difference), the suction header must also be able to take over the function of a suction accumulator. A radial inlet with baffle plate and a blunt pipe outlet to the top with separate oil return is recommended (see the following figure, part A).
Alternatively, a vertically arranged vessel with a blunt pipe outlet and separate oil return can be used (suction gas inlet from above). The pipe lengths to the compressors may be different. This design is also suitable for use on ships – with regard to inclinations.

Guidance of the suction header in parallel compounding with the suction header below the compressor level. The picture shows HS. compressors, but applies analogously to OS. compressors – but not for R717 applications, see Technical Information AT-640.
A: Blunt pipe outlet with separate oil return
B: Bevelled dip tubes
C: Parallel distribution (limited to two compressors)
D: Lateral pipe outlet – pipe exit downwards is not permitted.

Suction header above compressor level

This arrangement should only be chosen if there is no space for pipe layout from below. It requires a special pipe layout as shown here.

Guidance of the suction header in parallel compounding with the suction header above the compressor level. This arrangement is generally not recommended – for R717 systems, see Technical Information AT-640.