Azbil Micro Flow MQV0005, User Manual

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3-1
Chapter 3. MOUNTING AND WIRING
WARNING
Never allow gases that are within explosion limits (in particular, mixed gases within
explosion limits that contain hydrogen) to pass through this device. Doing so might
result in an explosion accidents.
When using this device for gases that contain hydrogen, be sure to purge the device
with an inert gas (such as nitrogen or argon) before use. Use without purging may
cause an explosion.
CAUTION
Check the product connections and pipe connections for leakage before use.
Also, check the connections for leakage regularly after the start of use.
It is the user’s responsibility to ensure that gas leaks can be reliably detected.
This is especially important if a dangerous gas is used.
Prevent foreign matter from entering the device. If rust, water droplet, oil mist, or
dust in the pipes enters the device, measurement or control error or damage might
occur.
If there is a possibility of foreign matter entering the device, provide a filter, strainer
or mist trap capable of eliminating foreign matter 0.1 μm or greater in diameter at the
upstream. Be sure to inspect and replace the filter at regular intervals.
This device is exclusively for hydrogen and helium gases. It cannot be used for control
or measurement of gases other than hydrogen, helium, and hydrogen-helium mix-
tures (excluding mixed gases within explosion limits). Oxygen cannot be measured
even if gascontacting sections of this device are oil-inhibited.
This device is set initially for hydrogen gas use at the factory. To use it for helium
gas or mixed gases, change the gas type setting. The use of this device for helium or
mixed gases without changing the gas type setting will result in a measurement error.
Use the device within the operating differential pressure range. Also, do not subject it
to pressure beyond the rated pressure resistance range. Doing so might damage it.
The valve on this device cannot completely shut a flow off. If complete shutoff is
required, provide a shutoff valve separately. When the external valve is closed, it
is necessary also to fully close the valve of the device using either of the following
methods:
• Set the flow rate setpoint to zero.
• Make the valve operation mode to fully closed.
If this valve remains in normal control status when the external shutoff valve is
closed (zero flow rate), there will be an excessively large flow as soon as the external
shutoff valve is opened. This excessive flow rate could activate the
AL83
alarm (op-
erated by the sensor safety circuit). If the sensor safety circuit is activated, flow rate
measurement and flow control are not possible until the power is turned off and
back on again.