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9. Other Instructions for Use
This section gives instructions for use and installation.
Follow these instructions to fit the pipes correctly and use the equipment safely.An example
of piping is shown below. Lay the lines appropriately to the conditions of use.
9.1 Entry of air bubbles into liquid supply line
If air bubbles enter the MV and the LF or XF for detecting the flow rate, the air bubbles can
cause fluctuation of output and variation of vaporization flow rate. Therefore, check the
liquid supply line taking the following points into consideration.
(1) The liquid supply tank (pressure tank for supply) and MV are different in installation level.
If the supply tank is installed at a lower level, the gas (pressure gas) dissolved in the
liquid in the supply tank is supplied to MV while the gas is in the saturated state. The
gas dissolved in the liquid in the saturated state reduces in pressure by gravity with rise
of the liquid level, and the gas dissolved in the saturated state is supersaturated and
turned into air bubbles in the liquid. The amount of gas dissolved in the liquid material
changes depending on the applied pressure, kind of pressure gas, kind of liquid material
and temperature. In this case, it is necessary to install an air bubble removing device
in the supply unit or install an air bubble separating device just before the LF or XF.
When an air bubble separating device is installed just before the LF or XF, reduce the
difference of level between the LF or XF and MV and the pressure loss of the piping to
prevent occurrence of air bubbles after the LF or XF.
(2) If the liquid is supplied at a dash into the piping under vacuum from the tank under pressure
to fill the piping at the beginning of liquid feeding, part of vapor and dissolved gas in the
liquid released into the vacuum piping becomes air bubbles. In this case, gradually
increase the tank supply pressure from the state close to vacuum after supplying the liquid
into the vacuum piping, or, if an air bubble separating device is installed on the MV side,
first feed the liquid to up to the air bubble separating device, and supply the liquid to MV, so
that air bubbles are not generated in the piping.
PF
MV
LF or XF
MFC
