Data Sheet

EH and EHA Valves
D100042X012
Product Bulletin
51.2:EH
April 2015
14
Figure 18. Bore Seal
FLOW DOWN
FLOW UP
PLUG
RETAINER
BORE SEAL
PISTON RING
CAGE
RETAINER
CAGE
BORE SEAL
PLUG
SEATING AREA
PISTON RING
SEATING AREA
A
VIEW A
BORE SEAL
CAGE
SEATING AREA
Bore Seal Description
The Bore Seal (figure 18) is available for the EHD only
and employs a variation of the proven Cseal trim with
enhancements for use with the larger port EH hung
cage. The Bore Seal is required for Class V shutoff
applications where the service temperature exceeds
316_C (600_F). See table 3 for availability and
temperature limits.
The Bore Seal employs a metal Cshaped seal ring that
is secured to the outside diameter of the valve plug.
When the valve plug comes into contact with the seat
ring to close the valve, the Bore Seal is compressed
against the cage wall, thereby blocking a secondary
leakage path that exists between the plug and cage
wall. When the valve plug is not in contact with the
seat ring (i.e. valve open), the Bore Seal is not engaged
and the piston rings that are also secured to the
outside diameter of the plug assume the role of
blocking this secondary leakage path.
Table 3. Bore Seal Availability and Temperature Limits (EHD only)
VALVE
(PRESSURE
CLASS)
VALVE SIZE, NPS
TRIM
DESIGNATION
(1)
VALVE BODY
MATERIAL
TEMPERATURE LIMIT
ANSI/FCI/IEC
SHUTOFF CLASS
_C _F
EHD
(CL1500 - CL2500)
8, 10, 12, and 14
75 WCC/WC9 29 to 427 20 to 800
V95
WCC 315 to 427 600 to 800
WC9 315 to 593 600 to 1100
96 WCC/WC9 29 to 427 20 to 800
1. See tables 11 and 13 for materials.