Process pump for chemical plants: a single-stage end-suction centrifugal pump built to ISO 2858 dimensions and the ISO 5199 Class II specification

01

ISO 2858 size code: inlet, outlet and nominal impeller diameter at a 16 bar rating

ISO 2858:1975, End-suction centrifugal pumps (rating 16 bar) — Designation, nominal duty point and dimensions, specifies the main parameters and a pump designation of three numbers, with a table covering flange sizes from 50 mm up to 200 mm; ISO last reviewed and confirmed it in 2017. [1] Convista's CH pump code follows the same pattern: in CH250-200-500, 250 is the inlet diameter, 200 the outlet diameter and 500 the nominal impeller diameter. [3]

MST describes its IH series as single-stage end-suction (axial suction) cantilever centrifugal pumps for corrosive liquids with water-like viscosity and without solid particles, designed jointly by the national industry using the ISO international standard, and lists other chemical process pumps whose size and performance comply with DIN 24256/ISO 2858. [4]

Editorial calculation: a CH250-200-500 has a 250 mm inlet, larger than the 200 mm top of the ISO 2858 flange table, so sizes above that range follow the same code but not the standard's dimension table; ask the supplier which sizes are dimensionally interchangeable to ISO 2858. [1] [3]

Give the supplier the liquid and its concentration, temperature, solids and viscosity, the duty point (flow and head) and NPSH available, suction and discharge pressure, the ISO 2858 size if replacing an existing pump, the specification to build to (ISO 5199 or other), the seal type and flush plan, and materials of construction.

02

ISO 5199 Class II build: CH-series impeller and seal variants and their operating limits

ISO 5199:2002, Technical specifications for centrifugal pumps — Class II, is the current edition, last reviewed and confirmed by ISO in 2018. [2] Convista builds its CH horizontal single-stage single-suction cantilever pump to GB/T 5656-2008, which it states is equal to ISO 5199:2002, for 2–2,000 m³/h, heads up to 160 m, operating pressure up to 2.5 MPa and temperatures below 150 °C, with a heavier shaft, larger shaft diameter and bearing spacing, and four variants. [3]

Convista lists its mechanical seals in regular and particle versions, and names duties including ionic-membrane caustic soda, salt making, chemical fertiliser, reverse osmosis, seawater desalination and MVR evaporation, where liquids may be clean or carry particles, and be corrosive, toxic, flammable or explosive. [3]

Editorial calculation: 2.5 MPa is 25 bar, above the 16 bar rating in the ISO 2858 title; confirm the casing pressure rating and hydrostatic test pressure for your discharge pressure rather than relying on the dimensional standard. [3] [1]

03

Send the liquid, duty point and build standard together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Liquid: [name; concentration; temperature; solids; viscosity]
Duty: [flow; head; NPSH available]
Pressure: [suction; discharge; casing rating]
Standard: [ISO 2858 size; ISO 5199 or other]
Build: [impeller type; seal and flush; materials]
Drive: [motor; baseplate; coupling guard]

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