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Operation
Test Procedures
Figure 11 - Test Gauge and Stem
Alignment
Figure 12 - Proximity Switch Location
Page 14
Stem Gauge
First confirm the proper location of the lower valve stem. Place a test gauge
(Figure 11, item A) as shown on the lower shoulder of the stem. The shoulder
should line up with the gauge.
Corrective Action: Check the stem assembly, ensuring that the lower stem is
fully turned in.
Confirm the yoke area proximity switch location for detection of upper stem
movement within 1/16". Insert a test gauge sideways between the detection cap
and the switch with the valve in the closed position.
The proximity switch (Figure 12, item C) should contact the gauge (item D, part
number 121672), without compressing the detection cap (item E).
Corrective Action: Loosen the proximity switch bolt and adjust the position.
Positive Fail-Safe Detection Test
Perform a test to verify the fully closed fail-safe position. Both the upper and
lower valve plugs are position-detectable via proximity switches. The valve plug
feedback proximity switches are to be set for the fully opened and fully closed
positions of the valve. See Figure 5 on page 11 for port and corresponding
chambers. See Figure 11 and Figure 12 on page 14 to confirm the stem and
switch positions using a stem gauge.
Decommission the system, drain the lines, and lock out the pumps.
1.
With the valve fully closed, confirm that the proximity switches conform to
Table 2 on page 12. Verify the switch status on the PLC control system.
2.
Pressurize chamber 1 to open the valve. Confirm that the proximity switches
conform to Table 2 on page 12.
3.
Vent chamber 1 to close the valve.
4.
Activate the upper seat lift either through the control system or manually by
supplying air to the air port in chamber 2.
5.
When the upper seat lifts, confirm that the proximity switches conform to
Table 2 on page 12. Verify the switch status on the PLC control system.
6.
Vent the air in chamber 2 to deactivate the seat lift.
7.
Activate the lower seat push either through the control system or manually
by supplying air to chamber 3 on the valve actuator.
8.
When the lower seat is pushed, confirm that the proximity switches conform
to Table 2 on page 12. Verify the switch status on the PLC control system.
9.
Vent the air in chamber 3 to deactivate the seat lift.
10. Disconnect the air from the valve actuator, placing the valve in the fail-safe
position. Verify that the proximity switches register that the valve is fully
closed.
Corrective Action
If the double seat mix proof valve fails to respond as indicated above,
immediately check the valve assembly and wiring to locate and correct the cause.
•
Check the proximity switch adjustment.
•
Check for the correct assembly and adjustment of the valve.
95-03076
Waukesha Cherry-Burrell
August 2008
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