Why are environmental controls valuable on Series 4300 VIL but not on other pumps, such as Series 4030 & 4280 end suction and Series 4380 VIL?
Series 4300 split coupled Vertical In-Line pump is designed with a throttle bushing beneath the seal cavity. The seal cavity is flushed from the pump discharge on the Series 4300 unit, and the throttle bushing is designed to “back up” the flush liquid by allowing a measured amount of fluid into the pump area, through machined grooves. This ensures that the mechanical seal is properly pressurized with sufficient liquid for lubrication and cooling. The throttle bushing also effectively isolates the seal cavity from the pump hydraulic area. As the mechanical seal can be sensitive to soluble and non-soluble abrasives in the system, the isolation of the seal cavity allows a very convenient opportunity to clean the liquid before it enters the mechanical seal area. The flush liquid may be cleaned up effectively by installing abrasive separators or filters in the seal flush line. The Series 4600 HSC design offers similar environmental control advantages, because the mechanical seal cavities ar
