American Petroleum Institute: Standard 682, 4th Edition Shaft Sealing Systems for Centrifugal and Rotary Pumps
Part 5 – Piping Plans
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This Fluid Sealing Association Knowledge Series training presentation introduces the American Petroleum Institute: Standard 682, 4th Edition. This is part of a series of presentations of this industry standard.
This presentation describes API-682 piping plans:
▪ Seal support piping plans and auxiliary hardware
▪ New piping plans in API-682 4th Edition
▪ This FSA training material is made available for informational purposes only and is made available “AS IS.” It is intended to serve only as a summary of the content of the API-682 standard and not as a substitute for or to replace or supersede the actual language of the API standard.
▪ For the full language of the API-682 standard, please refer to the actual standard and/or refer to API’s website for further information: https://www.api.org/products-and-services/standards. FSA disclaims any and all liability for any injuries or damages to persons or property resulting from reliance upon this informational summary.
Seal Support Piping Plans and Auxiliary Hardware
"Annex G"
▪ This annex contains drawings, descriptions, and tutorials of standard piping plans and auxiliary hardware that have regularly been used in industry. While not all of these plans are referenced in this standard, they may have applications in special cases with purchaser approval.
▪ The purpose of the piping plan is to control the environment in which the seal operates with respect to temperature, pressure, and cleanliness of the fluid.
▪ Dual Unpressurized Seals (outboard seal support only)
▪ Plans 52, 72, 75, 76
▪ Dual Pressurized Seals
▪ Plans 53 (A, B, and C), 54, 74
Further on these piping plans may be found via FSA knowledgebase: http://fsaknowledgebase.org
New 4th Edition Seal Support Piping Plans
▪ Plans 03, 55, 65A, 65B, 66A, 66B, 99
New Piping Plans to API-682 4th
Plan 03 - Seal chamber with built in flow modifiers
▪ Flow enhancement features built into the seal chamber geometry
▪ Generates or promotes circulation of seal chamber fluid
▪ Where it's used...
▪ Low duty Category 1 seals
▪ Applications with solids
▪ Pumps with tapered bores and no throat bushings
New Piping Plans to API-682 4th Edition
Plan 55 - External circulation of buffer fluid through arrangement 2 liquid seal
▪ Buffer fluid pressure maintained less than the process pressure
▪ Buffer fluid flow is created through external pump or pressure system
▪ Where it's used...
▪ Services where process fluid leakage to atmosphere should be minimized or contained
▪ Applications where the process may solidify in contact with atmosphere
▪ Applications where additional heat removal from the inner seal is required
New Piping Plans to API-682 4th Edition
Plan 65A - Collection and rate detection for condensing atmospheric leakage
▪ Orifice used to restrict flow rate of liquid leakage from collection reservoir
▪ Liquid leakage flow rates exceeding the orifice flow rate collects in the reservoir
▪ Liquid level sensor in reservoir alarms when excess liquid leakage flow fills the reservoir
▪ Where it's used...
▪ If pumped fluid condenses at ambient temperatures
▪ Typically, with Arrangement 1 seals utilizing a gland bushing or other containment device
New Piping Plans to API-682 4th Edition
Plan 65B - Collection and accumulation detection for condensing atmospheric leakage
▪ Valve used to keep flow of liquid leakage into the collection reservoir
▪ Liquid level sensor in reservoir alarms when reservoir is full
▪ Reservoir must be routinely drained
▪ Where it's used...
▪ If pumped fluid condenses at ambient temperatures
▪ Typically, with Arrangement 1 seals utilizing a gland bushing or other containment device
New Piping Plans to API-682 4th Edition
Plan 66A - Detection and monitoring of liquid atmospheric leakage
▪ Two (gland) throttle bushings on the atmospheric side of the seal
▪ Inner throttle bushing restricts liquid leakage flow rate from the inner bushing chamber
▪ Outer throttle bushing directs liquid leakage to collection system (I.E. plan 65A/B)
▪ Pressure sensor monitors changes in liquid leakage into inner bushing chamber
▪ Where it's used...
▪ Intended for use with Arrangement 1 seal applications
▪ Applications requiring leakage monitoring
▪ Commonly used on pipeline applications
New Piping Plans to API-682 4th Edition
Plan 66B - Detection and monitoring of liquid atmospheric leakage
▪ Single (gland) throttle bushing creates chamber on the atmospheric side of seal
▪ Orifice used to restrict flow rate of liquid leakage from the bushing chamber to a collection system (I.E. Plan 65A/B)
▪ Pressure sensor monitors changes in liquid leakage into bushing chamber
▪ Increased liquid leakage will fill the bushing chamber, generating pressure
▪ Where it's used...
▪ Intended for use with Arrangement 1 seal applications
▪ Applications requiring leakage monitoring with limited axial space
▪ Commonly used on pipeline applications
New Piping Plans to API-682 4th Edition
Seal Support Piping Plans
99
▪ Engineered piping plan not defined by other existing plans.
▪ In some challenging seal applications, it is necessary to design a piping plan for the specific characteristics of the seal, arrangement, process conditions or operating practices. The requirements for these applications may require modifications to existing piping plans or the creation of a new and unique plan.
▪ Piping Plan 99 defines an engineered piping plan. The description and requirements for this piping plan shall be clearly defined in specifications outside of this standard. Wherever possible though applicable requirements within this standard should be applied to the new piping plan.
▪ The decision to use a Piping Plan 99 may be made by either the purchaser or the supplier with purchaser’s approval.
Further Information
American Petroleum Institute Standard 682
For further information and detail please review the API 682 standards document.
Request a copy of the “API Std 682” from the API Publication
