4230 Flow Meter
Section 3 Installation
3-8
3.3.6 Effects of Changing the
Bubble Rate
Changing the bubble rate may cause a change in the indicated
level. Air flow through the relatively small diameter bubble line
generates a frictional back pressure or head in the bubble line.
For a given bubble rate, this frictional head is constant and
creates a fixed level offset for which level calibration automati-
cally compensates. However, increasing the bubble rate a signif-
icant amount (for example, from one to two bubbles per second)
will cause an increase in the frictional head and a consequent
increase in the indicated liquid level.
• Always set the bubble rate before you adjust the liquid
level reading on the flow meter.
• If you change the bubble rate for any reason, check and
compare the readings between the real level in the flow
stream and the indicated levels on the flow meter.
Adjust the indicated level if necessary. Since the friction head
generated at a given flow rate is a function of the bubble line
length and ID, you can minimize these frictional effects by using
the shortest length of bubble line possible.
3.3.7 Super Bubble The 4230 features an electronic “Super Bubble” feature that
detects a rapidly-rising liquid level and temporarily increases the
bubble rate to respond correctly to the rising level. Due to a
higher friction head generated by the increased bubble rate
during this operation, the flow meter will hold the indicated
liquid level constant until the bubble rate returns to normal.
3.4 4230 Mounting and
Installation
Because the 4230 Flow Meter is a portable device, it may or may
not be permanently installed. You can suspend the flow meter in
temporary installations, such as sewers, or mount it perma-
nently in other installations, such as treatment plants, at your
option.
3.4.1 Carrying Handle To assist in carrying the flow meter, a handle is provided in the
instrument's accessory package. To use the handle, snap the
hooks at both ends into the two metal brackets at the top of
either side of the flow meter case.
3.4.2 Location of the Flow
Meter
Because it uses a bubble line, the 4230 Flow Meter does not have
to be mounted directly above the primary device, or particularly
close to the flow stream. You will need to mount the unit within
25 feet (7.6 m), or 50 feet (15.3 m) if you are using the 50 foot
bubble line. Distances greater than 50 feet are not recommended.
The 4230 does not have any special requirements for mounting.
It may be located on any relatively flat surface either horizon-
tally, supported by the two mounting pads and the stainless steel
mounting bracket, or vertically, supported by the two plastic rails
on the bottom of the case. The flow meter may also be panel
mounted, using the mounting bracket on the top rear of the case
or suspended from a ladder rung or hook using the optional
handle.
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