# Non-standard Valve Modeling

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about START-PROF pipe stress analysis software

## Angular Valve With Equal Legs

If angular valve has equal legs, then it can be modeled using ordinary
valve element. Just put it into node between
two pipes. Pipes can have a different diameter. One half of valve length
will be placed through first pipe direction and one half through another.

## Angular Valve With Unequal Legs

If valve have unequal leg lengths, then it can be modeled using rigid
elements. The total weight of rigid elements should be equal to valve
weight. To model temperature expansion the temperature and material should
be specified in rigid element. Also flanges can
be added into end nodes of valve to check leakage.

## Three Way Valve

Three-way valve can be modeled just using 3 rigid
elements.

## Four Way Valve

START-PROF does not allow four elements
crossing in one node. A cross
can be modeled by moving the node of one of connecting elements by 1mm.
Three-way valve can be modeled using 4 rigid
elements. The total weight of rigid elements should be equal to valve
weight.

## Valve with Heavy Wheel, or Actuator Modeling

Heavy wheel or drive can be modeled as node weight load at the drive
center of gravity. This mass should be connected to valve using rigid
elements with zero weight to consider eccentricity. Proper modeling
of drive eccentricity is especially important for seismic analysis of
piping systems, because the eccentric mass will produce a great additional
torsion and bending moments on the piping system.