Flowserve V-370 R3 Edward Valves - Manual (Page 20)

EDWARD UNIVALVE USER INSTRUCTIONS ENGLISH 12-13
20
Correct Use of Impactor Handles/Handwheels to Close Applicable Univalves (Sizes 1-1/4 Through 4)
IMPACTOR HANDLE/HANDWHEELS
Impactor handle/handwheels increase the closing
effectiveness and eliminate the need for cheater bars.
Impactor handles/handwheels used on Edward Univalves
have the proven ability to achieve tight sealing, eliminating
leakage past the seats.They allow the recommended stem
loads on pg. 19 to be easily achieved.
Since they are smaller in diameter than standard
handwheels, they must be impacted multiple times to
develop the required torque. The number of impacts
required depends upon the size of the handle/handwheel,
the stem and seat size, and the differential pressure against
which the valve is being closed.
The values listed in the chart below are based on a standard
rating for the ability of plant personnel to accelerate the
handle/handwheel against the the stem adaptor. In addition,
these values assume that all parts are in good working
order (no binding or heavy dirt build-up on stem). The
figures given represent the minimum number of required
impacts, and exceeding them will not damage valves.
Failure to close these valves tightly, on the other hand, will
cause leakage, with resulting degradation of the sealing
surfaces over time.
OPERATIONAL RECOMMENDATIONS (continued)
IMPACTOR HANDLE/HANDWHEEL PERFORMANCE CHART
Maximum Shut-Off Pressure < 1000 PSIG
Maximum Shut-Off Pressure < 1500 PSIG
Maximum Shut-Off Pressure < 2000 PSIG
Maximum Shut-Off Pressure < 2500 PSIG
Maximum Shut-Off Pressure < 3000 PSIG
Maximum Shut-Off Pressure < 3500 PSIG
Maximum Shut-Off Pressure < 4000 PSIG 3
1.) See pages 10–13 for identification of torque groups A through E.
2.) Number of impacts listed are “minimum” values for corresponding shut-off pressure range.
3.) For shut-off pressures greater than 4000 PSIG, double the number of impacts recommended at 4000 PSIG for the applicable valve group.
22
20
18
16
14
12
10
8
6
4
2
0
22
20
18
16
14
12
10
8
6
4
2
0
Torque Group A 1 Torque Group B 1 Torque Group C 1 Torque Group D 1 Torque Group E 1
Number of Impacts Required for
Tight Closure
2
Impactor