American Petroleum Institute

Sealless Centrifugal Pumps for Petroleum, Petrochemical, and Gas Industry Process Service - SECOND EDITION
 N STD 685

Annotation

This standard specifies the minimum requirements for sealless centrifugal pumps for use in petroleum, heavy duty petrochemical and gas industry services. Refer to Annex A for application information. Notes following a clause are informative.

This standard is applicable to single stage overhung pumps of two classifications, Magnetic Drive Pumps (MDP) and Canned Motor Pumps (CMP). Sections 2 through 8 and Section 10 cover requirements applicable to both classifications. Section 9 is divided into two subsections and covers requirements unique to each classification.

NOTE: Extension of applicability to other designs such as multistage will need additional input and agreement between Purchaser and Supplier.

When application of sealless pumps is indicated, relevant industry operating experience suggests sealless pumps produced to this Standard may be used for many applications and should be applied when conditions exceed any of the following:

— Discharge pressure 1900 kPa (275 psig)

— Suction pressure 500 kPa (75 psig)

— Pumping temperature 150 °C (300 °F)

— Rotative speed 3600 r/min

— Rated total head 120 m (400 ft)

— Impeller diameter 330 mm (13 in.)

NOTE: For sealed pumps, refer to ISO Standard 13709 (API 610).