Brooks Instrument BM02 - Manual (Page 19)

3-3
Installation and Operation Manual
X-PD-BM01-02-eng
Part Number: 541B042AHG
March, 2008
Operation
Brooks ® Models BM01 and BM02
Operating the meter at flowrates in excess of the maximum allowable
flowrate will nullify the guaranteed accuracy, reduce the meter life and
may result in faulty conditions, such as seizure of bearings or rotor-to-
measuring chamber contact.
2. Where the temperature of metered fluid changes
Avoid rapid temperature changes in the meter. Temperature changes of
the fluid in the meter should be held within 3° C, 37° F per minute.
Extra care should be used particularly when making a flow measure-
ment in batch operation without the provision of heat tracing of the
piping where the fluid temperature differs from atmospheric temperature.
NOTE: If rapid temperature changes are anticipated, heat trace the piping
assembly as well as the meter.
3. Liquids of low steam pressure
Liquids with low viscosity and low steam pressure are prone to vaporize
and their temperature and pressure should, therefore, be strictly
controlled. During operation, the temperature of bearings in the meter is
usually higher than that of the metered fluid. Vapors around the bear-
ings can be causes of faulty conditions, including generation of unusual
noise and bearing seizure.
4. Corrosive liquids
When you make a measurement of highly corrosive liquids, appropriate
materials should be used for tanks and piping assembly. Heteroge-
neous materials originally contained in the metered fluid or corrosive
substances liquated out from tanks and pipes of inappropriate materials
may lock the rotors in the measuring chamber and lead to costly
downtime.
3-6 Precautions at Operation Shutdown
1. Valves should be closed progressively.
Rapid valve closure could, under certain piping conditions, cause a
sharp pressure rise by water hammer, or hydraulic shock, resulting in
damage to the meter.
2. Precautions against pressure buildup on closure.
Complete closure of valves upstream and downstream of the meter
produces a totally enclosed space between the valves. A pressure
buildup relative to a rise in atmospheric temperature could lead to
damage to the meter.
3. Liquids that readily adhere or gel.
Liquids that tend to adhere and solidify or gel at flow velocities around
zero must thoroughly be washed away from the meter interior with
running cleaning fluid before shutdown. Negligence of this precaution
could produce an immovable mass of components when the operator
attempts to resume meter operation.
NOTE: Turn pump off at end of each day.
After the flowmeter has been installed, slowly allow the liquid to flow in
bypass section of a horizontal installation or the main line of a vertical
installation. This will clear the line of any foreign particles.