MIDTERM Flashcards
THE LAST ACTIVE ELEMENT OF A CONTROL LOOP
FINAL CONTROL ELEMENT
DEVICE THAT RECEIVES A CONTROL SIGNAL AND REGULATES THE AMOUNT OF MATERIAL OR ENERGY IN A PROCESS
FINAL ELEMENT
MOST COMMON FINAL ELEMENT
CONTROL VALVE
A VALVE BODY AND ACTUATOR THAT IS ABLE TO CONTROL FLUID FLOW AT ANY POSITION BETWEEN FULLY OPEN AND FULLY CLOSED
THROTTLING CONTROL VALVE
THE PATH THROUGH THE VALVE BODY FROM THE INLET TO THE OUTLET PORT
WAY
THE LOCATION WITHIN THE VALVE BODY WHERE INTERNAL PARTS ARE PLACED TO DIRECT FLUID FLOW THROUGH THE VALVE
POSITION
THE VALVE DOES NOT ALLOW THE PRESSURIZED FLUID TO FLOW OUT OF A VALVE IN THE SPRING ACTUATED POSITION.
NORMALLY CLOSED (N/C)
THE VALVE DOES ALLOW THE FLUID TO FLOW OUT OF A VALVE IN THE SPRING ACTUATED POSITION.
NORMALLY OPEN (N/O)
VALVE PLUG STEM
VALVE PLUG
CAGE
SEAT RING
PRIMARY TRIM COMPONENTS
PACKING
PACKING FLANGE
PACKING GLAND
FLUSHING RING
SECONDARY TRIM COMPONENTS
THE HOUSING COMPONENT OR SHELL OF THE VALVE. CONNECTED TO PROCESS VIA FLANGED OR THREADED PIPING CONNECTIONS
BODY
THE SEAL AREA AROUND RHE SLIDING STEM.
PACKING AND PACKING BOX
THE MOVING ASSEMBLY CONNECTED TO THE SLIDING STEM, MOVES IN AND OUT OF VALVE SEAT. ALSO REGULATES FLOW
DISC OR PLUG
THE PART OF THE VALVE THAT PROVIDES THE MOVEMENT OF THE STEM ASSEMBLY.
ACTUATOR
THE PUSHING AND PULLING ROD THAT TRANSFERS MOTION FROM THE ACTUATOR TO THE PLUG
STEM (SHAFT)
STATIONARY RECEIVER FOR THE PLUG
SEAT
FORCES THE VALVE STEM IN THE OPPOSITE DIRECTION OF THE DIAPHRAGM ASSEMBLY.
SPRING
FLEXIBLE DISK THAT TRANSFERS THE PNEUMATIC FORCE TO MOVE THE VALVE STEM
DIAPHRAM
MANUAL OVERRIDE THAT LIMITS THE MOTION OF THE VALVE, FORCES IT TO STAY OPEN, CLOSED, or THROTTLED
HANDWHEEL
CONVERTS AN ELECTRICAL SIGNAL TO PNEUMATIC SIGNAL
I/P TRANSDUCER
THREE FAIL SAFE MODES:
- F/C
- F/O
- FAIL LAST POSITION
2 ANSI EMERGENCY CLASSES
V & VI
WHAT IS THE EMERGENCY CLASS ?
ANY CLASS PAST VI
3 REQUIREMENTS FOR FIRESAFE SHUTOFF:
- WITHSTAND 45 MIN. OF DIRECT FLAME IMPINGEMENT
- ELEMENT AND SEAT MADE FROM DIFF. MATERIALS
- SEATS ARE SPRING LOADED TO PUSH INTO ELEMENT FOR COMPLETE SHUTOFF
TO ACHIEVE THE DESIRED SHUTOFF FOR A PARTICULAR APPLICATION.
VALVE LAPPING
IS APPLIED TO SEATING AREA OF ELEMENT CREATE AS TIGHT A SEAT TO ELEMENT MATCH AS POSSIBLE
LAPPING COMPOUND
50% = 80%
MAX FLOW WITH MINIMAL TRAVEL
QUICK OPENING CAGE
50% = 50%
EQUAL INCREMENTS OF TRAVEL
EQUAL PERCENTAGE
MINIMUM CROSS-SECTIONAL AREA OF THE FLOW STREAM AND OCCURS JUST DOWNSTREAM OF THE ACTUAL RESTRICTION
VENA CONTRACTA