. As the vehicle speed approaches 60 km/h the governor pressure rises sufficiently to force back the 3–2 control valve piston, thus causing the wasted (reduced diameter) part of the control valve to complete the exhaustion of oil.
lowered, the hydraulic pump is applied to bring the bottom plate of the mould to the lower limit. The separator is then lowered into the mould and fed with the shell and the inner core materials. The vibrator is switched on for 5 s to consolidate the content. The space created by consolidation is topped up. The vibrator is switched on again while the separator is extracted from the moulds. The top of the content of mould is flattened, and the mould lid closed and clamped. With the
raised, the hydraulic pump is engaged to stress the content to the desired compaction pressure, which was readable on the gauge. The mould lid is opened and with the control valve raised, the block is ejected from the mould.
arrangement (Fig. 4) used here together with the 3% cavitation criterion in Fig. 2 is considered to be an industry-based and reliable method for determination of NPSHR in the pump best efficiency region, ISO .