Siemens LMV3 series, Технические инструкции

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Technical Instructions LMV Series
Document No. LV3-1000
Appendix A Page 14 SCC Inc.
Pilot Valve Proving
Introduction
Valve proving detects if the main gas valves in a gas train are leaking. In addition to checking
the main gas valves, the pilot valves may be tested for leakage as well. There are three options
for performing pilot valve proving:
•
Option 1: On Startup with SKP25’s on both the Pilot and Main Gas Trains
•
Option 2: On Startup, SKP25 on the Main Gas Train, Solenoid Valves on the Pilot Train
•
Option 3: Pilot Valve Proving on Startup and Main Valve Proving on Shutdown
On the LMV3, valve proving of the main gas valves can be performed during startup, during
shutdown, or during both startup and shutdown of the boiler. If pilot valve proving is added
using Option 1 or Option 2, valve proving must be performed during startup of the boiler only.
If pilot valve proving is added using Option 3, valve proving must be performed during both
startup and shutdown of the boiler.
Pilot valve proving can be performed on any LMV3.
Procedure
1. The valve proving type can be set in the LMV3 using parameter 241. For Option 1 or
Option 2, this must be set to a 1 (valve proving on startup only). For Option 3, this must
be set to a 3 (valve proving on both startup and shutdown).
2. The times for each of the four stages of valve proving need to be set. To do so, use the
following parameters in the LMV3:
Parameter 242 is the time that the downstream valve is energized in order to evacuate
the chamber between the upstream and downstream valves (phase 80). This is typically
set to 3 seconds, but should not be set any less than the opening time of the valves.
Parameter 244 is the time that the upstream valve is energized in order to pressurize
the chamber between the upstream and downstream valves (phase 82). This is typically
set to 3 seconds, but should not be set any less than the opening time of the valves.
Parameter 243 is the time that both the upstream and downstream valves are closed to
test the leakage rate of the upstream valve (phase 81). Parameter 245 is the time that
both the upstream and downstream valves are closed to test the leakage rate of the
downstream valve (phase 83). Both of these times should be set to the same value.
These times can be calculated using the following equation: