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This Fluid Sealing Association Knowledge Series training presentation introduces API Piping Plan 62. A description is provided on:
▪ What is an API Plan 62?
▪ How an API Plan 62 works
▪ What does an API Plan 62 do?
▪ What an API Plan 62 cannot do
▪ Optional Features for an API Plan 62
▪ Cost to Operate an API Plan 62
▪ How to Size an API Plan 62
▪ How to Install an API Plan 62
▪ General API Plan 62 Commissioning Guidelines
▪ How to Operate an API Plan 62
▪ General Troubleshooting of an API Plan 62
▪ Alternatives to an API Plan 62
What Are Piping Plans?
▪ Piping plans collectively are different piping arrangements of fluid used to improve the conditions the mechanical seal operates in with the objective of improving the mechanical seal’s life.
▪ The American Petroleum Institute adopted numbers and created definitions for each piping plan configuration, thereby allowing a common language across the industry to simply describe a particular configuration.
▪ The American Petroleum Institute standard API-682 is where the definition of each piping plan can be found and where they may periodically be updated.
What
is an API Plan 62?
Plan 62 options
Quench media
▪ Gas
> Please visit FSA’s Knowledgebase for more details
▪ Liquid > Described in this document
▪ Multi-phase (Steam)
> Please visit FSA’s Knowledgebase for more details
What is an API Plan 62? (Liquid Quench)
API Plan 62 is the most common atmospheric flush plans in use across the industry.
This flush plan provides a delivery of quench liquid (typically water) to the atmospheric side of a mechanical seal, typically injected between the mechanical seal and an atmospheric bushing.
Valve
Variable Area Flow Meter
Valve Check Valve
Isolation
Needle
How an API Plan 62 Works (Liquid Quench)
An API Plan 62 works by injecting an external quench liquid to the atmospheric side of a mechanical seal. The quench liquid is contained within the atmospheric quench cavity by a containment device, typically a lip seal, close clearance bushing, or other device. The flow and pressure of the external quench liquid is controlled through
auxiliary devices. Pressure is regulated to within a few fractions of an atmosphere and is always less than the seal chamber pressure. The quench liquid exits the atmospheric chamber via an atmospheric drain port and via leakage past any quench containment device.
Quench liquid entry to atmospheric side of the seal
How an API Plan 62 Works (Liquid Quench)
An API Plan 62 support system is often a panel mounted group of instruments and valves that regulates the flow of liquid to the quench port on the mechanical seal. Typically, water is used as the quench medium since it is readily available at most facilities.
Following the flow path of the liquid through the API Plan 62 system:
Isolation valve – Isolates the liquid source from the mechanical seal to allow for maintenance.
Check valve – Prevents back flow of process fluid in the event of an abnormal process upset or catastrophic seal failure.
How an API Plan 62 Works (Liquid Quench)
Pressure regulator – Reduces the liquid supply pressure to being delivered to the mechanical seal.
Needle Valve – Used to make fine adjustments to the quench liquid flow rate.
Flow Meter – Provides an indication of the quench liquid flow rate.
What
does an API Plan 62 do? (Liquid Quench)
An API Plan 62 with a liquid quench media, typically water, is used to:
▪ Dissolve and remove crystallization resulting from evaporation of pump fluid leakage.
▪ Wash away solids and debris from seal leakage.
▪ Provide cooling to the mechanical seal environment.
An API Plan 62 liquid quench is commonly used in fluids with dissolved inorganic chemicals, suspended solids, and slurries.
What an API Plan 62 cannot do (Liquid Quench)
An API Plan 62 with a liquid quench media does not:
▪ Remove atmospheric coking deposits as the result of seal leakage in hot services.
▪ Prevent the formation of ice in cold or cryogenic pumping applications.
▪ Function correctly when freeze risks are present.
▪ Eliminate atmospheric emissions.
API Plan 62 with gaseous or steam quench media may provide solutions to the above limitations of an API Plan 62 with liquid quench media.
Optional Features for an API Plan 62 (Liquid Quench)
In-line Filter - A filter/strainer to trap particles that potentially can damage the mechanical seal and containment seal.
Pressure Gauge – Can be provided to indicate the supply pressure and/or downstream pressure of the regulator.
Pressure Transmitters - Can be used to provided local and remote indication of the supply pressure and/or downstream pressure of the regulator.
Flow Transmitter – Can be used to provided local and remote indication of the quench flow rate.
Quench containment options
▪ Fixed bushing ▪ Floating bushing
Segmented bushing
Lip Seal Optional Features for an API Plan 62 (Liquid Quench)
Optional Features for an API Plan 62 (Liquid Quench)
Drain options
▪ Low point drain to prevent bearing contamination/corrosion
Optional Features for an API Plan 62 (Liquid Quench)
Bearing isolators
▪ Install robust bearing isolator (such as labyrinth or face seal style) to prevent contamination of bearings
Image courtesy of Sepco
Cost to Operate an API Plan 62 (Liquid Quench)
There is a cost associated with operating an API Plan 62 as the quench liquid is constantly being consumed whether the pump is operating or not. The operating costs can vary as the cost of the liquid, carbon footprint of producing the liquid, and the flow regulation settings, will govern the actual operating costs.
Cost to Operate an API Plan 62
With adequate flow control instrumentation, the cost to operate an API Plan 62 is relatively low.
Refer to the Fluid Sealing Association’s Lifecycle Cost Calculator (LCC) for a more detailed analysis.
How to Size an API Plan 62 (Liquid Quench)
The flow rates required for an API Plan 62 with a liquid quench can vary from as low a 60 ml/hr (1 GPH) to 1 l/min (0.25 GPM). The delivery pressure to the seal for the quench liquid is typically in the range of 0.3 to 0.6 Barg (5 to 10 psig) or less.
Consideration needs to be made to the pumping fluid temperature and seal face heat generation to ensure the quench fluid remains in the liquid state.
The Fluid Sealing Association recommends working with your mechanical seal vendor whenever a more precise minimum quench flow rate is required.
How To Install an API Plan 62 (Liquid Quench)
API Plan 62 instrumentation is typically panel mounted on a stand that can be placed in a position near the pump that allows sufficient space for maintenance and inspection activities. It does not need to be mounted immediately adjacent to the mechanical seal.
The instrumentation panel is commonly constructed using tubing components but may also be constructed from pipe components or a combination of tube and pipe components. The instrument panel and stand should be grounded to earth.
The instrument panel delivering the quench liquid is connected to the mechanical seal quench connection, typically labeled “Q” or “Quench”.
When present, connect a drainpipe to the drain connection, typically labeled “D” or “Drain” to direct the quench liquid to a closed sewer or recovery system.
General API Plan 62 Commissioning Guidelines (Liquid
Quench)
To commission an API Plan 62:
1) Using the mechanical seal assembly drawing, verify that the quench and drain piping are connected to the correct ports in the mechanical seal.
2) Open the pressure and/or flow control valve(s) and adjust to achieve the target flow rate.
3) Check all the connections on the API Plan 62 piping for leaks. Correct any if found.
4) The API Plan 62 must be operational before starting the equipment.
5) Ensure any drain ports are unplugged, and quench flow is directed to a closed sewer or recovery system.
How to Operate an API Plan 62 (Liquid Quench)
Operation of an API Plan 62 requires maintaining a continuous flow of quench liquid to the mechanical seal.
During operation:
▪ Periodically check the quench liquid flow rate.
▪ Periodically check for leaks at the connections.
During routine maintenance of the mechanical seal, inspect the overall condition and function of the quench system and replace or repair any defective components found.
General Troubleshooting of an API Plan 62 (Liquid Quench)
Extended operation of a mechanical seal with low or no quench flow can cause premature seal failure and excessive leakage to atmosphere.
There are three main events that can reduce or eliminate the effectiveness of an API Plan 62:
1) Loss of source liquid pressure
2) Blockage or fail-closed of any flow control component
3) Clogging of the drain connection
A local flow meter or remote indicating flow transmitter can detect these events indicating a flow below the target flow rate. When detected, the control components should be diagnosed and replaced or repaired as required.
Alternatives to API Plan 62 (Liquid Quench)
Alternative piping plans that are similar:
API Plan 62 Summary (Liquid Quench)
An API Plan 62 with a liquid quench flowing on the atmospheric side of a mechanical seal will:
▪ Dissolve and remove crystallization resulting from evaporation of pump fluid leakage.
▪ Wash away solids and debris from seal leakage.
▪ Provide cooling to the mechanical seal environment.
Flow to the mechanical seal is controlled by a series of flow control devices and regulated to low pressure. These instruments can be conveniently panel mounted and installed near the pumping equipment.
