API 685, 3rd Edition – Sealless Centrifugal Pumps for Petroleum, Petrochemical, and Gas Industry Process Service

API 685 covers the minimum requirements for sealless centrifugal pumps for use in petroleum, heavy-duty petrochemical, and gas industry services. Refer to Annex O for application information. Notes following a clause are informative.

API 685 is applicable to single-stage overhung pumps of two classifications, magnetic drive pumps (MDPs) and canned motor pumps (CMPs). 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 the purchaser and the supplier. Considerations for multistage sealless pumps are given in Annex Q.

If application of sealless pumps is indicated, relevant industry operating experience suggests that sealless pumps produced to this standard should be considered for pumping liquids at conditions exceeding any of the following:

— discharge pressure 1900 kPa (275 psig);

— suction pressure 500 kPa (75 psig);

— pumping temperature 150 °C (300 °F);

— rated total head 120 m (400 ft).

NOTE For sealed pumps, refer to API 610.