Condensate pots play a key role in maximising the accuracy of differential pressure flow measurement on steam or vapour applications. When installed correctly, these simple devices can significantly improve flow measurement accuracy in differential pressure measurement systems by providing an interface between the vapour and liquid phases.
Condensate pots also prevent flashing of liquid in the impulse line, which can occur if there is a sudden change in the temperature of the steam.
As a result, condensate pots are widely used in applications such as refineries, power generation plants, chemical and petrochemical, steel plants and other process industries as they provide an interface between the vapour phase and the condensed phase in the impulse lines. They also facilitate the minimisation of gauge line error caused by pressure differences in pairs of impulse lines.
Parker’s condensate pots are suitable for use either on vertical or horizontal lines, between the primary (Flow Meter) and the secondary (transmitter/gauge) to act as a barrier to the line fluid, allowing direct sensing of the flow conditions.
The correct installation of condensate pots, however, is really important to ensure long service life and maximum efficiency.
Make sure you evaluate the number of connections required on the condensate pot before ordering (for example, inlets, outlets, fill port, drain port, gas vent port.) This ensures that the Condensate pot meets your specific application requirements.
Carefully define the condensate pot volume in litres, system pressure, and temperature requirements. This is important as the size of the pot needs to relate to the volume of steam passing through the steam pipeline.
It may be necessary to trace heat and insulate all impulse lines. This ensures that the vapour phase is maintained in the tube lines between the pipeline and the condensate pot. It may also be required to prevent freezing in the liquid lines between the condensate pot and the transmitter.
Consider adding an anti-freeze media, such a glycol, to the water lines. This may be essential in climates where below-freezing temperatures are reached.
Keep vapour impulse lines as short as practicably possible. This ensures that the steam can remain in this state and requires minimal or no heating.
Ensure both condensate pots are mounted at the same level, minimising possible errors that could arise due to an unequal head of fluid in the connecting pressure lines. This should take into account both vertical and horizontal steam pipelines. The higher connection point should be the reference.
The differential pressure measuring device (DP) should be mounted below both the condensate pots and the steam pipeline.
It is recommended that both impulse lines from the condensate pot to the DP include the facility for ‘blowdown’. Blowing down these lines periodically prevents the collection of debris, which could impact on measurement accuracy.
Ensure both the high pressure (HP) and low pressure (LP) impulse lines are the same length, which should eliminate pressure head errors. The theory of operation for condensate pots is that between the process taping and the pot is steam vapour. Between the pot and the differential pressure transmitter is water (liquid) thus eliminating any measurement errors due to a liquid/vapour mix at the measurement device.
It is advisable to select condensate pots as part of a complete Parker instrumentation solution. We can supply all associated valves, manifolds, tubing, and fittings alongside condensate pots, ensuring that all components work together and providing added reassurance about accuracy and safety. This also includes providing tube line heating and insulation to ensure performance is maximised.
Parker's condensate pot pressure ratings are for temperatures up to 100°C. We can also supply condensate pots to meet other pressures and temperatures. The most commonly used materials to manufacture condensate pots are steel, 316, 304, 6MO stainless steel and monel.
For more product details visit our online ecommerce website or view our condensate pot brochure.
Article contributed by Graham Johnson, small-bore product marketing manager - EMEA, Instrumentation Products Division Europe.