Page 140 - Introduction to Marine Engineering
P. 140
126 Pumps and pumping systems
Handwheel
Cover
Split ring
Figure 6.12 Globe valve
Cover
Body
/ / / / /A Figure 6.13 N on-return valve
Non-return or check valves are arranged in various pipelines to
prevent reverse flow. Where the valve disc is not attached to the spindle
it is known as screw-down non-return (SDNR). The valve disc in such a
valve must have some form of guide or wings to ensure it can reseat
correctly when screwed closed. Non-return valves are sometimes
arranged without spindles, in which case they are liquid operated and
