morning edit

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Robin Clark 2011-02-11 10:41:41 +00:00
parent e1d190178a
commit 2e2d7492d7
2 changed files with 39 additions and 6 deletions

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@ -271,24 +271,32 @@
howpublished = "http://www.cmis.bton.ac.uk/research/vmg/papers/", howpublished = "http://www.cmis.bton.ac.uk/research/vmg/papers/",
year = "2007" year = "2007"
} }
@MISC{en161,
author = "E N Standard",
title = "EN161:2007 Automatic shutoff valves for gas burners and gas appliances"
howpublished = "British standards Institution http://www.bsigroup.com/",
year = "2003"
}
@MISC{en298, @MISC{en298,
author = "E N Standard", author = "E N Standard",
title = "Gas Burner Controllers with forced draft", title = "EN298:2003 Gas Burner Controllers with forced draft",
howpublished = "EN298", howpublished = "British standards Institution http://www.bsigroup.com/",
year = "2003" year = "2003"
} }
@MISC{en60730, @MISC{en60730,
author = "E N Standard", author = "E N Standard",
title = "Automatic Electrical controls for household and similar use", title = "EN60730: Automatic Electrical controls for household and similar use",
howpublished = "EN60730", howpublished = "British standards Institution http://www.bsigroup.com/",
year = "1994" year = "1994"
} }
@MISC{en61508, @MISC{en61508,
author = "E N Standard", author = "E N Standard",
title = "Functional safety of electrical/electronic/programmable electronic safety related systems", title = "EN61508:2002 Functional safety of electrical/electronic/programmable electronic safety related systems",
howpublished = "EN61508", howpublished = "British standards Institution http://www.bsigroup.com/",
year = "2002" year = "2002"
} }

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@ -58,6 +58,31 @@ slowly when voltage too low
\section {Four Current Failure Mode Analysis Methodologies} \section {Four Current Failure Mode Analysis Methodologies}
\subsection{Working Example: Gas Valve Proving}
For each methodology outlined in the following sections,
an example will be provided using an industiral safeguard
used in the combustion industry. This example is
the arrangement of three valves~\cite{en161} to the gas supply to the burner.
The first two valves in the chain are emergency shutdown valves.
These are mains (line voltage) powered devices, that
raise the valve opening against a strong spring. If the
power is removed, they snap shut. The third valve
regulates the flow of fuel into the burner.
Between valve 1 and 2 there is a length of pipe,
of a given volume.
At start up
this is tested, by opening valve
2 and checking the pressure reading is ambient pressure.
Valve 2 is then closed and valve 1 is opened
allowing gas to enter the volume.
At start up gas is allowed to enter the first valve and presurises
the space between it and valve 2. The pressure is monitored for a given time
to ensure that valves 1 and 2 are not leaking.
\subsection { FTA } \subsection { FTA }
\glossary{name={FTA},description={Fault Tree Analysis}} \glossary{name={FTA},description={Fault Tree Analysis}}