Operating Conditions, Fluid Compatibility & Pressure/Temperature
Flow Meter Fill Rite TN 740 Operating the flow meter in excess of its maximum design capacity, can cause excessive wear or premature failure.
In many cases it is necessary to consider all operating conditions in combination.
In addition to liquid, pressure & flow rate, correct material/seal selection often depends upon % concentration, pH value & operating temperature.
If in doubt about compatibility of a specific fluid, please refer to the Chemical Compatibility List, or consult with Customer Care to verify compatibility of chemicals with the wetted materials.
The flow meter should not be operated in excess of pressure rating. Care should be taken to eliminate the possibility of thermal or hydraulic shock conditions.
At elevated temperatures (> 120°F = 50°C), meter pressure rating is reduced. Please consult with Customer Service for pressure rating at higher operating temperatures.
All TN700 & TN800 Series models are factory calibrated for service on liquids with viscosity within a specific range.
To use a flow meter on a another liquid with different viscosity characteristics, will typically require a different set of gears in the ratio gear plate, plus calibration.
When designing the pipe system, it is important to include following considerations:
• Flow Meter Fill Rite TN 740 How to keep air out of the system once operating. PD meters will run on air, but air is recorded as liquid and it may result in damage to flow meter. Presence of air is a contributing factor to ‘water hammer’ conditions.
• Hydraulic shock can damage system components, either directly or as cumulative effect of many small shocks. Design the system to avoid excessive liquid velocity, long supply lines & sudden valve closure.
• Liquid expansion due to minor temperature changes can result in line pressure many times normal, if relief valves are not installed. A thermal relief valve is required in any system segment, where the meter can be trapped between two closed valves.
• Direction of flow can be Left-to-Right, Right-to-Left or Up. The flow meter can face either up or out. However, do NOT run this flow meter backwards (see “Flow Direction Arrow” on meter case).
• In critical process service, block valves and a bypass are recommended. This allows the flow meter to be serviced without interruption of flow.
• Means for flow meter calibration should be included. This can be:
• A single connection to divert liquid into a proving can.
• A dual connection separated by a valve, to permit hook-up of a master meter.
• Future maintenance and service for both flow meter & strainer; both components can be serviced in-line, provided that there is room to work.