Page 63 - Valve Selection Handbook

50 Valve Selection Handbook

rating of welding end valves corresponds frequently to the rating of
flanged valves. However, standards may permit welding end valves to be
36
designed to special ratings that meet the actual operating conditions. If
the valve contains components made of polymeric materials, the pressure-
temperature relationship is limited, as determined by the properties of the
polymeric material. Some standards for valves containing such materials
as ball valves specify pressure-temperature limits for the valve. Where
such standards do not exist, it is the manufacturer's responsibility to state
the pressure and temperature limitations of the valve.

Valve Selection Chart

The valve selection chart shown in Table 3-1 is based on the foregoing
guidelines and may be used to select the valve for a given flow-regulat-
ing duty. The construction material of the valve is determined on one

Table 3-1
Valve Selection Chart
Valve Mode of Flow Regulation Fluid

Free of Solids in Suspension
Group Type On-Off Throttling Diverting solids non-abrasive abrasive Sticky Sanitary
Closing Globe:
down -straight pattern Yes Yes Yes
-angle pattern Yes Yes Yes special special
-oblique pattern Yes Yes Yes special
-multiport pattern Yes Yes
Piston Yes Yes Yes Yes special
Sliding Parallel gate:
-conventional Yes Yes
-conduit gate Yes Yes Yes Yes
-knife gate Yes special Yes Yes Yes
Wedge gate:
-with bottom cavity Yes Yes
-without bottom Yes moderate Yes Yes
cavity (rubber seated)
Rotating Plug:
-non-lubricated Yes moderate Yes Yes Yes Yes
-lubricated Yes Yes Yes Yes Yes
-eccentric plug Yes moderate Yes Yes Yes
-lift plug Yes Yes Yes Yes Yes
Ball Yes moderate Yes Yes Yes
Butterfly Yes Yes special Yes Yes Yes
Flexing Pinch Yes Yes special Yes Yes Yes Yes Yes
Diaphragm:
-weir type Yes Yes Yes Yes Yes Yes
-straight-through Yes moderate Yes Yes Yes Yes