OPERATION
Swivldisc Gate Valves are designed for on-off service and should normally be either fully opened or fully closed. The valve stems have single pitch left hand threads with clockwise rotation of the handwheel to close.
The Swivldisc Gate Valve has a backseat feature which, in the fully open position, isolates the packing from line pressure thereby increasing packing life. This backseat is pressure actuated and requires only a light torque to effect sealing.
The recommended assembly and operating torques for the Swivldisc Gate Valve are given in table 2.
NOTE: ALWAYS CHECK PACKING GLAND TIGHTNESS PRIOR TO TAKING VALVE OFF OF BACKSEAT.
|
VALVE |
YOKE |
BACKSEAT |
GLAND |
SEATING |
||
|
MAX |
MIN |
|||||
|
1/2 |
150 |
70 |
4 |
20 |
30 |
|
|
1 |
150 |
70 |
4 |
20 |
30 |
|
|
1 1/2 |
250 |
100 |
6 |
35 |
60 |
|
|
2 |
450 |
170 |
12 |
60 |
160 |
|
|
2 1/2 |
600 |
220 |
12 |
60 |
300 |
|
|
3 |
750 |
275 |
18 |
90 |
350 |
|
|
4 |
900 |
325 |
25 |
145 |
500 |
|