Liquid Controls MA4 Meter - Manual (Page 5)

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• The meter must always be securely bolted to a
platform or supporting member, regardless of the
mounting position of the meter. Never “hang” a meter
on the connecting pipe.
! ! ! ! ! WARNING
When a Back Check Valve is used, an automatic safety
valve must be installed to prevent pressure build-up in
excess of rated working pressure in the meter housing.
One automatic safety valve should be installed in each
meter. Remove the pipe plug from the front cover or
rear cover and insert the appropriate automatic safety
valve.
• Position the meter with service in mind. Provide
ample work space. Removing covers can be difficult
when work space is not available. Always supply a
platform or support for the meter mounting.
• A meter is metallurgically designed to be physically
compatible with a given type of liquid, as originally
specified by the customer, and as indicated on the
Serial Number Plate. A meter should not be used
with a liquid different from the liquid originally
specified, unless the physical characteristics and pH
rating are similar and the application has been
checked with Liquid Controls Sales or Engineering.
Installation & Operation Requirements
Operation Requirements
The meter must remain full of product at all times. An
easy way to accomplish this is to put the meter assembly
in the line below the piping center-line (a sump position).
This requires adding elbows and flanges prior to installing
the meter. The meter should be installed in a bypass loop,
below the pipe center-line, with block valves upstream
and downstream. A block valve should be located in the
mainstream, labeled as the bypass valve. A word of
caution: any portion of pipe system that might isolate or
block flow should be provided with a pressure relief to
prevent damage from thermal expansion. There are
excellent benefits to this type of installation. First, the
meter is kept full. Second, this type of installation allows
the meter to be isolated for servicing and calibration while
continuing flow through the bypass valve.
Upstream lines must be maintained full to prevent air
from entering the meter. If the upstream or inlet lines are
constructed in a manner which allows reverse flow, foot
valves or back checks must be installed.
Position the meter with service in mind. Make sure there
is ample work space. Removing the meter covers can
be difficult when ample work space is not available.
Always supply a platform or support for the meter
mounting.
Every meter should be calibrated under actual service
and installation conditions per the API Manual of
Petroleum Measurement Standards:
Chapter 4 - Proving Systems
Chapter 5 - Metering
Chapter 6 - Metering Assemblies
Chapter 11 Section 2.3 - Water Calibration of
Volumetric Provers
Chapter 12 Section 2 - Calculation of Petroleum
Quantities
These chapters of the API Manual of Petroleum
Measurement Standards supersede the API Standard
1101.
Provide a means of conveniently diverting liquid for
calibration purposes.
Give careful attention to your system’s pumping
equipment and piping because of their influence on liquid
being measured as it enters the meter assembly. Systems
should be made free of conditions that cause or introduce
entrained air or vapor.
Follow the manufacturer’s recommendations fully when
installing pumps. Give particular attention to factors like:
use of foot valves, pipe size to the inlet and conformance
to net positive suction head (NPSH) conditions when
suction pumping is required. Following the manufacturer’s
recommendations will minimize air and vapor elimination
problems.
For liquids such as light hydrocarbons that tend to flash
or vaporize easily at higher ambient temperatures, it is
desirable to use flooded suctions and piping sized larger
than the normal pump size.
Hydraulic shock is harmful to all components of an
operating system including valves, the meter and the
pump. In particular, meters must be afforded protection
from shock because of their need to measure with high
precision. Generally the best protection is prevention,
which can be readily accomplished by adjusting valve
closing rates in such a manner that shock does not occur.
Thermal expansion like hydraulic shock is a phenomenon
that can easily damage meters and systems in general.
Care should be taken in designing the system to include
pressure relief valves in any portion or branch of the
system that might be closed off by closure of operating
valves or block valves.